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1.	Jareman, Fredrik, et al. (författare) Effects of aluminum content on the separation properties of MFI membranes 2003 Ingår i: Separation and Purification Technology. - 1383-5866 .- 1873-3794. ; 32:1-3, s. 159-163 Tidskriftsartikel (refereegranskat)abstract MFI membranes with almost identical film thickness and defect distribution but different Si/Al ratio were evaluated by separation of butane and hexane isomers. Film thickness was evaluated by SEM and defect distribution by porosimetry. When the temperature was varied, the membranes showed similar separation trends for butanes, but clear differences were observed for hexane separation. The hexane separation factor varied with temperature for the silicalite-1 membrane but was constant for the ZSM-5 membrane. It is believed that this difference may be a result of differences in adsorption properties.
2.	Privalova, E., et al. (författare) CO2 removal with 'switchable' versus 'classical' ionic liquids (vol 97, pg 42, 2012) 2013 Ingår i: Separation and Purification Technology. - Amsterdam : Elsevier. - 1383-5866 .- 1873-3794. ; 107, s. 340-340 Tidskriftsartikel (refereegranskat)
3.	Ahmad, Arslan, et al. (författare) Impact of phosphate, silicate and natural organic matter on the size of Fe(III) precipitates and arsenate co-precipitation efficiency in calcium containing water 2020 Ingår i: Separation and Purification Technology. - : ELSEVIER. - 1383-5866 .- 1873-3794. ; 235 Tidskriftsartikel (refereegranskat)abstract Removal of arsenic (As) from water by co-precipitation with Fe(III) (oxyhydr)oxides is a widely used technique in water treatment. Nevertheless, As removal efficiency appears to be sensitive to the composition of the water matrix. The aim of this study was to gain a deeper understanding of the independent and combined effects of silicate (Si), phosphate (P), natural organic matter (NOM) and calcium (Ca) on arsenate [As(V)] co-precipitation efficiency and the size of Fe(III) precipitates. We found that, in complex solutions, containing multiple solutes and high levels of Ca, (variations in) Si and P concentrations reduce As(V) removal to some extent, mainly due to a decreased adsorption of As(V) onto Fe(III) precipitates. On the other hand, NOM concentrations reduced As(V) removal to a much greater extent, due to possible formation of mobile Fe(III)-NOM complexes that were difficult to remove by filtration. These findings have a great significance for predicting As(V) removal as a function of seasonal and process-related water quality changes at water treatment plants.
4.	Ahmad, Arslan, et al. (författare) Mechanisms of arsenate removal and membrane fouling in ferric based coprecipitation-low pressure membrane filtration systems 2020 Ingår i: Separation and Purification Technology. - : ELSEVIER. - 1383-5866 .- 1873-3794. ; 241 Tidskriftsartikel (refereegranskat)abstract Ferric based coprecipitation-low pressure membrane filtration is a promising arsenic (As) removal method, however, membrane fouling mechanisms are not fully understood. In this study we investigated the effect of feed water composition and membrane pore size on arsenate [As(V)] removal and membrane fouling. We observed that As removal efficiency was independent of the membrane pore size because the size of the Fe(III) particles was larger than the pore size of the membranes, attributed to a high calcium concentration in the feed water. Arsenic coprecipitation with Fe(III) (oxyhydr)oxides rapidly reached equilibrium before membrane filtration, within 1 min. Therefore, As removal efficiency was not improved by increasing residence time before membrane filtration. The removal of As(V) was strongly dependent on feed water composition. A higher Fe(III) dose was required to reduce As(V) to sub-mu g/L levels for feed water containing higher concentration of oxyanions such as phosphate and silicate, and lower concentration of cations such as calcium. Cake-layer formation was observed to be the predominant membrane fouling mechanism.
5.	Ahmad, Sheikh Asrar, et al. (författare) Use of digital thruster to separate the cadmium and lead metals from mixture sample 2008 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 63:1, s. 101-106 Tidskriftsartikel (refereegranskat)abstract The present work deals with the use of a digital thruster (DT) for the separation of cadmium and lead metals from mixture samples. Mixtures of lead and cadmium salts with varying concentrations were injected into a free electrolytic diffusion apparatus (FEDA). The microcathodes surrounding the central anode were programmed witha DT. The DT distributed the charge over the microcathodes at time intervals of 100-900 mu s or at the frequency of 625-70 Hz. The microcathodes become electrodeposited with lead and cadmium metals, showing both separation and co-deposition. The purity of deposited metals was analyzed by Atomic Absorption Spectroscopy (AAS) using PerkinElmer and Aldrich AAS standards. (C) 2008 Elsevier B.V. All rights reserved.
6.	Al-Rudainy, Basel, et al. (författare) From lab-scale to on-site pilot trials for the recovery of hemicellulose by ultrafiltration: Experimental and theoretical evaluations 2020 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 250 Tidskriftsartikel (refereegranskat)abstract Spent sulfite liquor (SSL) is a byproduct of the sulfite pulping process of wood. SSL usually contains monosugars and lignosulfonates, which are fermented to produce ethanol and dried to generate lignosulfonate salts. However, the SSL that was used in this work was derived from the first step of a 2-step sulfite pulping process of softwood under mild pulping conditions in the first stage of cooking. The resulting SSL contained polymeric hemicelluloses, which are not used today but have many potential applications. The up-concentration of this SSL had been performed on a lab scale by ultrafiltration. However, the pilot-scale ultrafiltration of hemicellulose-rich sodium-based SSL has not been reported. In this study, the operating conditions for the lab-scale concentration of hemicellulose-rich, sodium-based SSL were examined in a pilot-scale membrane filtration unit. The permeate flux and retention of products were lower in the pilot equipment compared with the lab-scale setup, perhaps related to the lower Reynolds number and shear rate in the former, as indicated by simulations of computational fluid dynamics. The pilot equipment also ran at a higher volume reduction compared with the lab-scale system, which could explain the difference in flux and retention. The effects of fouling and cleaning were also determined, wherein an alkaline cleaning step (pH 11) for 1 h was sufficient to remove foulants and maintain a stable average flux of 88 L/m2h and the nonchanging retention of products.
7.	Arkell, Anders, et al. (författare) Evaluation of membrane performance and cost estimates during recovery of sodium hydroxide in a hemicellulose extraction process by nanofiltration 2013 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 118, s. 387-393 Tidskriftsartikel (refereegranskat)abstract The recovery the alkaline solvent from of a residual stream after the extraction of hemicelluloses in wheat bran was investigated. The solution was withdrawn from an ultrafiltration (UF) process in which hemicelluloses were recovered. The UF permeate, containing mainly NaOH, lignin and mono- and oligosaccharides, was treated by nanofiltration (NF). Seven NF membranes were tested in a parametric study, and the two membranes showing the best performance were further evaluated in a concentration study. The mean flux of a Koch SelRO MPF 36 and a Microdyn-Nadir NP010 membrane was about 200 l/m2 h during concentration to a volume reduction of 0.75. The retention of NaOH was <20%, while the retention of lignin and sugars was about 70% and >95%, respectively. Cost estimates for a NaOH recovery process indicated that an NF plant would have a pay-back time of less than 2 months if the plant was run continuously, and 7 months if it was used 25% of the time.
8.	Arkell, Anders, et al. (författare) Influence of heat pretreatment on ultrafiltration of a solution containing hemicelluloses extracted from wheat bran 2013 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 119, s. 46-50 Tidskriftsartikel (refereegranskat)abstract Hemicelluloses extracted from wheat bran can be concentrated and purified by ultrafiltration. However, the viscosity of the process solution is rather high (about 5 mPa s at 80 C and a shear rate of 100 s1), which results in a relatively low flux. The solution was subjected to heat pretreatment in an attempt to decrease the viscosity and increase the flux. Pretreatment of the solution at 80 C for 72 h was found to reduce the viscosity by 25%. The flux during ultrafiltration with a 10 kDa ceramic membrane increased from 48 l/m2 h, for the untreated solution, to 62 l/m2 h. The increase in flux was lower than expected, and this was attributed to the formation of a fouling layer of acid-insoluble compounds on the membrane. Both hemicelluloses and lignin were partly degraded. The retention of lignin was reduced from about 30% to 18%, whereas the retention of hemicelluloses was above 95%, and was not affected by heat pretreatment. The decrease in lignin retention after heat pretreatment results in improved separation of hemicelluloses and lignin, facilitating the purification of hemicelluloses.
9.	Bergström, Jonas, et al. (författare) Literature review of experimental hydrocyclone flow field studies 2007 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 53:1, s. 8-20 Tidskriftsartikel (refereegranskat)abstract The complex flow field of hydrocyclones has been experimentally investigated on several occasions. Most studies present similar results for the tangential velocity component. In the inner part of the cyclone, it resembles a solid-body rotation, while it typically has a free-vortex-like behavior in the outer part. When looking at the axial velocity component, the results are more diversified. Most studies show a downward velocity close to the wall and an upward velocity in the center. However, some studies report a heavily varying axial velocity over short radii close to the centerline. The radial velocity component appears to be the most problematic one to measure. Dissimilarities in measurement results between the studies are often greater than similarities. However, later studies agree on an increasing inward radial velocity towards the hydrocyclone center. Despite the obvious relationship, extremely little experimental research work can be found in the literature where changes to the flow field are connected to changes in separation efficiency.
10.	Butylina, Svetlana, et al. (författare) Separation of nucleoprotein complexes with antioxidant activity from yeast Saccharomyces cerevisiae 2007 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 53:1, s. 64-70 Tidskriftsartikel (refereegranskat)abstract In this study, complexes of nucleic acids and acidic nuclear proteins were isolated from baker's yeast cells of Saccharomyces cerevisiae by mild alkaline extraction followed by precipitation with acetic acid. The optimal composition of the buffer applied for extraction of nucleoprotein complexes was determined. The high and low molar mass fractions of the nucleoprotein complexes were separated using cross-flow microfiltration through track-etched membranes. The molar masses were determined by intrinsic viscosity measurements and the molar mass distribution in nucleoprotein complexes was studied by gel permeation chromatography. The protein component of the nucleoprotein complexes was purified on a strongly basic anion exchange resin. The high molar mass nucleoprotein complexes could induce the growth of culture cells of S. cerevisiae exposed to ultraviolet irradiation or treated with hydrogen peroxide
11.	Chen, Lan, et al. (författare) Innovative aryl-based hydrophobic deep eutectic solvent for efficient removal of dyes and nanoplastics 2023 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 308 Tidskriftsartikel (refereegranskat)abstract Efficient absorption is a highly important strategy to remove environmental pollutants (i.e., dyes and nano plastics), which relays on the development of innovative and sustainable absorbents. Herein, we designed an innovative aryl-based deep eutectic solvent (DES) using diphenylamine (DPA) and benzophenone (BZP) as the component at a molar ratio of 1:1, and this novel DES was denoted as DPA:BZP-1:1. The developed DPA:BZP-1:1 could efficiently adsorb RhB and PS nanoparticles from their aqueous solution/suspension, and the absorption efficiency could reach up to 97.3% and 80%, respectively. Notably, DPA:BZP-1:1 showed a higher absorption efficiency than commercial activated carbon. Experimental and computational results revealed that hydrogen bonding and 7C-7C stacking synergistically contributed to the excellent absorption ability of DPA:BZP-1:1 on dye Rhodamine B (RhB) and polystyrene (PS) nanoplastics. To the best our knowledge, this is the first study on efficient absorption of dye and nanoplastics by aryl-based DESs.
12.	Chen, Yifeng, et al. (författare) Developing aqueous porous carbons for biogas upgrading 2024 Ingår i: Separation and Purification Technology. - : Elsevier B.V.. - 1383-5866 .- 1873-3794. ; 329 Tidskriftsartikel (refereegranskat)abstract Developing novel sorbents is essential for biogas upgrading. In this study, mixed sorbents of aqueous porous carbons were developed to separate CO2 from the biogas, where the porous carbon with the developed micropore structure was identified as the most desirable constituent. Both thermodynamics and kinetics were studied experimentally, and Henry’s constant (KH) and the liquid-side mass-transfer coefficient (kL) of CO2 in the mixed sorbent as well as the selectivity of CO2/CH4 were obtained accordingly. Furthermore, the CO2 separation performance was evaluated with a proposed index, and the cost of biogas upgrading using the mixed sorbent was estimated and compared. The results showed that the porous carbon with the developed micropore structure led to better performance on KH and kL of CO2 in the mixed sorbent, and the mixed sorbent with 3.03 wt% porous carbon exhibited the best CO2 separation performance, reducing 36.2 % in cost compared to the current technologies.
13.	Chen, Yuran, et al. (författare) In-depth purification of spent pot-lining by oxidation-expansion acid leaching: A comparative study 2022 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 303 Tidskriftsartikel (refereegranskat)abstract Spent pot lining (SPL) is a hazardous solid waste generated after overhauling the aluminum electrolytic cell. SPL contains carbon resources with high graphitization and toxic impurities, such as NaF, Na3AlF6, and CaF2. These toxic substances are difficult to remove from graphite completely. This study introduces an innovative method of oxidation-expansion acid leaching (OEAL) to eliminate impurities inside the graphitized carbon. For such a purpose, typical purification methods (conventional leaching, flotation-acid leaching) were investigated and compared to OEAL. The experimental outcomes indicated that the process efficiency for removing SPL impurities by various methods had the following sequence from high to low: OEAL > flotation-acid leaching > conventional leaching. The maximum SPL impurities removal rate by conventional leaching and flotation-acid leaching was 89.65 %, while it was 99.36 % with the OEAL method. For understanding fundamental aspects of the SPL impurity removal, their rejection mechanisms in the examined methods were systematically studied by different instrumentals and chemical analysis techniques. As a result of the reaction between H+ and residuals during OEAL process, the distance between graphitized carbon layers expands. This expansion resulted in a qualitative improvement in the SPL impurity removal by OEAL, making SPL one of the graphite or graphene oxide resources.
14.	Chen, Yifeng, et al. (författare) Kinetics study and performance comparison of CO2 separation using aqueous choline-amino acid solutions 2021 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 261 Tidskriftsartikel (refereegranskat)abstract The thermodynamic and kinetic properties of CO2 in aqueous choline-amino acids ([Cho][AA]s) are important information to demonstrate their performance. In this study, the apparent kinetic properties of CO2 in the five aqueous [Cho][AA]s, including the liquid-side mass-transfer coefficients, enhancement factor, and reaction rate constant, were systematically studied. Furthermore, a new ‘‘absorption ability’’ (AA) index was proposed, combining the apparent kinetic properties determined in this study and thermodynamic properties determined in our previous study. The CO2 separation performance using aqueous [Cho][AA]s was evaluated based on the AA and CO2 desorption enthalpy values. The results show that 30 wt% aqueous choline-serine is a promising absorbent for CO2 separation, and it is comparable to aqueous monoethanolamine.
15.	Chen, Yifeng, et al. (författare) Kinetics study and performance evaluation of a hybrid choline-glycine/polyethylene glycol/water absorbent for CO2 separation 2023 Ingår i: Separation and Purification Technology. - : Elsevier B.V.. - 1383-5866 .- 1873-3794. ; 304 Tidskriftsartikel (refereegranskat)abstract Thermodynamic and kinetic properties of absorbents are beneficial in evaluating their CO2 separation performance. In this study, the kinetic properties of CO2 in a hybrid choline-glycine/polyethylene glycol/water absorbent, including the liquid-side mass-transfer coefficient, enhancement factor, and reaction rate constant, were systematically determined through experimental measurements and data processing. Furthermore, an index referred to as “absorbility” was proposed to combine the kinetic properties determined in this study with the thermodynamic properties obtained in our previous study to evaluate the CO2 separation performance. Additionally, the regeneration performance of the hybrid absorbent was also conducted. The results show that the performance of the hybrid absorbent (30 wt% [Cho][Gly] + 10 wt% PEG200 + 60 wt% H2O) is comparable to that of aqueous monoethanolamine, and is thus promising for CO2 separation, considering its low regeneration temperature and low environmental impact.
16.	Chen, Yuran, et al. (författare) Resource utilization strategies for spent pot lining: A review of the current state 2022 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 300 Forskningsöversikt (refereegranskat)abstract During a long-term operation of the aluminum electrolysis cell, the molten salts continuously infiltrate and corrode the pot lining, resulting in a huge amount of hazardous waste after the overhaul. The first cut of spent pot linings (SPL) contains several carbon-rich materials with potential economic value and hazardous matters such as soluble fluorite and cyanide. The continuous accumulation and disposal of SPL in depots or landfills have created a severe challenge to the aluminum industry. Nowadays, the technologies of harmless disposal and resource utilization of SPL have been paid more attention. This work has explored and presented the properties of SPL (including chemical, physical, and thermodynamic properties, etc.) and methods for its detoxification and purification. In this regard, the resource utilization strategies of SPL are systematically sorted out from three aspects: traditional, co-processing, and high-value technologies. In the end, the current challenges and future perspectives for the environmental recycling of SPL have been analyzed and summarized.
17.	Chipakwe, Vitalis, et al. (författare) Exploring the effect of a polyacrylic acid-based grinding aid on magnetite-quartz flotation separation 2023 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 305 Tidskriftsartikel (refereegranskat)abstract It is well documented that the use of grinding aids (GAs) can reduce milling energy consumption. However, the impact of GAs on downstream processes must be addressed in view of complex processes such as froth flotation separation. This study investigates the effects of polyacrylic-based grinding aids (Zalta™ GR20-587: AAG) on the grinding performance and quartz flotation from magnetite. Various AAG dosages and conditions were examined. The grinding results showed lower energy consumption and a finer, more uniform product size with roughened surfaces for AAG compared to grinding without the grinding aid. Flotation tests of single pure minerals showed that AAG enhanced quartz collection with minimal effect on magnetite. Mixed mineral flotation showed that by using AAG, Fe recovery of 92.1 % and 64.5 % Fe grade could be achieved with a lower collector dosage of 100 g/t compared to 200 g/t in the absence of AAG. Zeta potentials and stability measurements showed that AAG shifts the potential, thus improving the stability and dispersion of the suspension. Adsorption tests illustrated that AAG adsorbed on both quartz and magnetite, the former having a higher capacity. FTIR indicated the physisorption interaction between AAG and the minerals. Therefore, the presence of AAG not only improved grinding efficiency but could potentially decrease the amount of collector required to achieve comparable metallurgical performance.
18.	del Pozo, David Fernandes, et al. (författare) A novel CFD model to predict effluent solids concentration and pressure drop in deep bed granular filters for water treatment 2022 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 295 Tidskriftsartikel (refereegranskat)abstract Rapid sand filtration is a widely used technology to remove suspended solids in drinking water and wastewater treatment plants. One of the challenges of the rapid sand filtration is to reliably predict the removal efficiency of suspended solids and pressure drop as a function of filtration time. In this study we put forward a novel CFD model to simultaneously predict the solids concentration in the effluent and hydraulic resistence build-up in rapid sand filters. The CFD model is assessed against lab scale filtration data at different filter media grain sizes and filtration velocities. Our results show an overall satisfactory agreement with the observations. Finally, we highlight the complexity and need for further work in developing general CFD models for rapid sand filtration.
19.	Durruty, Julie, 1988, et al. (författare) Local filtration properties of Kraft lignin : The influence of residual xylan 2017 Ingår i: Separation and Purification Technology. - : Elsevier B.V.. - 1383-5866 .- 1873-3794. ; 179, s. 455-466 Tidskriftsartikel (refereegranskat)abstract The influence of lignin and xylan interactions on the filtration properties of precipitated LignoBoost lignin was investigated. LignoBoost lignin was (i) suspended in acid water with xylan added and (ii) dissolved together with xylan and then re-precipitated. The resulting lignin-xylan mixtures were more difficult to filter than the original LignoBoost lignin, although the formed filter cake was also found more porous in the case of re-precipitated solids. Furthermore, the pressure dependency of the filtration properties was shown to increase after the addition of xylan. One possible explanation based on the findings presented in this paper is that xylan is sorbed at the surface of the lignin agglomerates: it increases the contact area between solid and liquid, thus making the particle structure more porous. The influence of ionic strength was also investigated through the addition of sodium sulphate: it was found that increasing the ionic strength of the slurries made the solids easier to separate, possibly due to a decrease in electrostatic repulsive interactions between the solids and the formation of a denser solid structure.
20.	Essalhi, Mohamed, et al. (författare) Development of a Lycopodium powder-based superhydrophobic nanofiber membrane suitable for desalination 2023 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 323 Tidskriftsartikel (refereegranskat)abstract A biobased, green, inexpensive additive, Lycopodium particles, which are spores of the “Lycopodium clavatum” plant, were incorporated in the poly(vinylidene fluoride) PVDF electrospun nanofiber membranes (ENMs) for desalination by direct contact membrane distillation (DCMD). Superhydrophobic ENMs were prepared using this additive (PVDF-ENMs-Lyc). Thanks to their morphological structure and their prominent surface superhydrophobicity (anti-wetting) character, the resulting PVDF-ENMs-Lyc exhibited an improved liquid entry pressure (LEP), a high void volume fraction (greater than 87.2%), a good salt rejection factor (greater than 99.93%) and a reasonably high permeate flux (greater than 51.76 kg·m-2·h-1) at 80 °C, which are of great practical importance for water desalination by DCMD. The optimum membrane prepared with 3 wt% Lycopodium in the dope solution demonstrated a stable permeate flux of 52.4 ± 0.6 kg·m-2·h-1 with an electrical conductivity around 4.76 ± 0.46 μS/cm (NaCl rejection factor of 99.998 ± 0.036%) during 25 h DCMD desalination experiment using 35 g/L NaCl aqueous solution (similar to seawater concentration). The presented results pave the way for superhydrophobic nanofibrous membrane engineering suitable for membrane contactors by electrospinning in a single step without surfactants, organic additives, or chemical post-treatments, just by the incorporation of a green additive like Lycopodium powder.
21.	Feldt, Emma, 1995, et al. (författare) Temperature and concentration dependence of the electrochemical PtHg4 alloy formation for mercury decontamination 2023 Ingår i: Separation and Purification Technology. - 1873-3794 .- 1383-5866. ; 319 Tidskriftsartikel (refereegranskat)abstract New and improved methods to remove toxic mercury from contaminated waters and waste streams are highly sought after. Recently, it was shown that electrochemical alloy formation of PtHg4 on a platinum surface with mercury ions from solution can be utilized for decontamination, with several advantages over conventional techniques. Herein, we examine the alloy formation process in more detail by mercury concentration measurements using inductively coupled plasma mass spectrometry in batch measurements as well as electrochemical quartz crystal microbalance analysis both in batch and in flowing water with initial mercury concentrations ranging from 0.25 to 75000 µg L−1 Hg2+. Results show that mercury is effectively removed from all solutions and the rate of alloy formation is constant over time, as well as for very thick layers of PtHg4. The apparent activation energy for the electrochemical alloy formation was determined to be 0.29 eV, with a reaction order in mercury ion concentration around 0.8. The obtained results give new insights that are vital in the assessment and further development of electrochemical alloy formation as a method for large scale mercury decontamination.
22.	Flyborg, Lena, et al. (författare) A PLS model for predicting rejection of trace organic compounds by nanofiltration using treated wastewater as feed 2017 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 174, s. 212-221 Tidskriftsartikel (refereegranskat)abstract In this study a Partial Least Squares Projection of Latent Structures (PLS) model has been developed for predicting the rejection of pharmaceutical residuals by nanofiltration (NF) using treated municipal wastewater as feed. The objective was to provide a practical tool for wastewater reuse facilities for estimating the rejection of emerging organic contaminants based on their physiochemical characteristics. The model was developed by identifying the important physiochemical properties of pharmaceutical residuals for rejection by NF. The investigated pharmaceuticals were those present in the effluent from Henriksdal wastewater treatment plant (WWTP), Sweden. The rejection, at volume reduction factors (VRF) ranging from 2 to 20, was examined in a NF pilot plant at two occasions. The important variables for rejection by NF were, in descending order: polarizability, globularity, ratio hydrophobic to polar water accessible surface area and compound charge. Two studies were performed with a time interval of about a year with different wastewater matrices and age of membranes. For different VRFs, but in the same study, the model produced consistent predicted rejections. For the same VRF, but in the different studies, the regression lines were almost parallel, but with a deviation of about 7% for the predicted values. Most of the compounds were within the 95% prediction interval. The model also proved to be able to predict rejection using data from the literature. This confirms that the predictive PLS model can estimate the rejection albeit, with limitations. Generally the proposed predictive rejection model is most likely valid but the model coefficients need to be determined for each individual WWTP or wastewater reuse facility.
23.	Foorginezhad, Sahar, et al. (författare) Development of Monoethanolamine Chloride-Ethylene Diamine Deep Eutectic Solvent for Ffficient Carbon Dioxide Capture 2024 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 347 Tidskriftsartikel (refereegranskat)abstract Deep eutectic solvents (DES) emerge as a compelling class of ionic liquids, with distinct advantages over traditional solvents, particularly in the realm of CO2 capture. In the present study, [MEACl][EDA] is synthesized across various molar ratios (1:3 to 1:10) and combined with the results of Differential Scanning Calorimetry (DSC) to identify DESs. The DESs are further characterized using Fourier Transform Infrared Spectroscopy (FTIR), and the properties and performance of the DESs with diverse water contents (30–60 wt%) are systematically studied for CO2 capture. The optimal aqueous solution is identified based on the CO2 uptake and viscosity, followed by the evaluation of the cyclic absorption experiments. Results demonstrate that 40 wt% of [MEACl][EDA] DES with (1:5) molar ratio exhibits higher CO2 uptake (22.09 wt%) and comparable viscosity (4.401 mPa·s before and 13.330 mPa·s after CO2 capture at 25 °C) compared to aqueous 40 wt% MEA (15.74 wt% CO2 capture capacity, viscosity of 3.318 mPa·s before and 8.413 mPa·s after CO2 capture), and its absorption rate is also more favorable than the aqueous MEA. Furthermore, recycling studies reveal ∼ 88 % regeneration of the aqueous DES solution at 100 °C.
24.	García-Martín, Noemi, et al. (författare) Sugar reduction in musts with nanofiltration membranes to obtain low alcohol-content wines 2010 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 76:2, s. 158-170 Tidskriftsartikel (refereegranskat)abstract Our aim here is to study the sugar reduction in musts to obtain wines with a slight alcohol reduction by nanofiltration. Specifically, sugar reduction is achieved by two successive nanofiltration steps. To test the method, we have worked with two types of musts: a white must from Verdejo grapes and a red one from Tinta de Toro grapes. The musts obtained from the nanofiltration treatment have been mixed with untreated must or with the retentate of the first nanofiltration stage in a proportion adequate to reduce the alcohol content of the resulting wines by 2 degrees.To verify the effectiveness of the process, each of these musts has been fermented along with an untreated control sample of the same must. The alcohol reduction in the wines has been satisfactory. However, a slight loss in the color and aroma of some compounds has been detected. (C) 2010 Elsevier B.V. All rights reserved.
25.	Gentili, Francesco (författare) Chitosan-β-cyclodextrin composite flocculants dual-drive for efficient microalgae harvesting: Structural evidences, dehydration process, E-DLVO model behavior and biomass utilization 2024 Ingår i: Separation and Purification Technology. - 1383-5866 .- 1873-3794. ; 339 Tidskriftsartikel (refereegranskat)abstract Flocculation is one of the promising methods for harvesting microalgae. In this study, a series of grafted cationic chitosan-cyclodextrin composite flocculants (CTS/beta-CDs) with different structural properties were prepared from chitosan and cyclodextrin. The results showed that the harvesting efficiency of CTS/beta-CD-1 for C. vulgaris reached 99.91%. The chain type of polymeric flocculants with moderate graft chain lengths (L = 10-20) and tighter branched chain density distribution (D = 1.0-1.8) was favorable for C. vulgaris harvesting. The addition of CTS/ beta-CDs caused the discrete C. vulgaris cells to be flocculated and aggregated, and the reorganization of particles resulted in larger particles after flocculation, improving the dewatering performance of microalgae flocs. CTS/ beta-CDs had no significant inhibitory effect on the extraction of lipids, proteins and carbohydrates, and did not affect the extraction and quality of fatty acid methyl esters, and the re-cultivation experiments of the harvested water showed that chitosan-based flocculant was able to effectively reduce the cost of microalgae harvesting. Electrostatic interactions and bridging were the main harvesting mechanisms between CTS/beta-CD-1 and C vulgaris. E-DLVO modeling suggested that flocculation is mainly a result of electrostatic and acid-base interactions when the distance between particles is small. At higher pH, the harvesting efficiency of CTS/beta-CD-1 with C. vulgaris decreased. The study contributes to a better understanding of the structure-activity relationship between the structural characteristics of flocculants and the harvesting performance.
26.	Habibi, Hossein, et al. (författare) Separation and recovery of titanium and scandium from the red mud 2023 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 317 Tidskriftsartikel (refereegranskat)
27.	Hafeez, Ainy, et al. (författare) Synergetic Effect of Packed-bed Corona-DBD Plasma Micro-Reactor and Photocatalysis for Organic Pollutant Degradation 2021 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 269 Tidskriftsartikel (refereegranskat)abstract A packed-bed Corona-DBD hybrid plasma micro-reactor is coupled with a novel heterogeneous photocatalyst-AgFeO2/CNTs/TiO2 for methyl orange degradation. The corona nature of the plasma produces a high concentration of active species, yet maintaining a homogeneous discharge owing to the dielectric barrier nature of the reactor. The submicron channels in the plasma reactor created by glass beads increased dielectric strength and simultaneously produced high energy streamers, which increased the ozone generation by 24%. The AgFeO2/CNTs/TiO2 photocatalyst gave stretched adsorption edge (400-500 nm), reduced bandgap energy (2.3 eV), facilitated degradation under visible light, and provided the additional advantage of the Fenton process, leading to the OH. formation. The three reaction systems were investigated and compared for MO degradation-photocatalysis, plasma reactor and integrated plasma photocatalysis reactor which gave 1.2%, 50.8%, and 95% removal in 2 minutes respectively. The solution pH, dosage, and loading of AgFeO2 in photocatalyst was investigated. The integrated plasma photocatalysis gave 95% degradation of 250 ml solution of 30 ppm methyl orange at pH 3 with 0.5 g/l of 2.5% AgFeO2/CNTs/TiO2 photocatalysis in 2 minutes. The integrated plasma photocatalysis reactor increased the number density of active species, particularly, OH. in wastewater which makes it a good choice for azo dyes degradation.
28.	He, Yingnan, et al. (författare) Separatable MoS2 loaded biochar/CaCO3/Alginate gel beads for selective and efficient removal of Pb(II) from aqueous solution 2022 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 303 Tidskriftsartikel (refereegranskat)abstract Centimeter-scale composite biochar-alginate gel beads (MoS2B/CaCO3/Alg) were designed for the adsorption of Pb(II) in water using MoS2 modified biochar as the filler, alginate as the matrix, and CaCO3 as the active additive component. The composite gel beads were characterized using scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and other techniques. MoS2B/CaCO3/Alg showed excellent adsorption capacity over a wide range of pH 4–7. The maximum adsorption capacities obtained using the Langmuir model were 769.2, 833.3, and 909.1 mg g−1 at 10, 25 and 40 °C, respectively. At a dosing rate of 0.4 g L−1, MoS2B/CaCO3/Alg was able to reduce the Pb(II) concentration to below 0.05 ppm in complex simulated lead battery wastewater. After 10 repeated cycles, MoS2B/CaCO3/Alg maintained a high removal rate of 98.4 %. This spherical adsorbent is simple to prepare and easy to recover, has an ultra-high adsorption capacity, and is mechanically stable and resistant to interference, thus it is expected to be suitable for application in industrial wastewater treatment.
29.	Hedlund, Jonas, et al. (författare) Microchannel Zeolite 13X Adsorbent with High CO2 Separation Performance 2021 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 277 Tidskriftsartikel (refereegranskat)abstract Uniform 13X films with thicknesses of 3 and 11 µm were grown on supports in the form of steel monoliths with a cell density of 1600 cpsi and microchannels width of 0.5 mm. Sharp breakthrough fronts and a dynamic uptake of 3.4 mmol CO2 g-1 zeolite were observed in the forwarding step of breakthrough experiments for a feed of 10 % CO2 in N2 with a high flow rate at 293 K and 1 bar. Numerical modeling showed that the adsorption process was very fast and that the transport of CO2 in the thin zeolite layer was the rate-limiting step, the mass transfer resistance for the 11 µm film is 2.2 times lower than zeolite 13X pellets and 100 times lower than zeolite 4A beads. Axial dispersion, pressure drop, and gas film resistance were shown to be negligible. The steel monolith support provides good mechanical strength and excellent thermal conductivity for the 13X films. The combination of properties makes this adsorbent a good performer when compared with other types of structured zeolite adsorbents in reported literatures. This microchannel adsorbent is a promising alternative to traditional adsorbents in processes of fast CO2 separation with short cycle times.
30.	Hu, Kaibo, et al. (författare) Highly selective recovery of rare earth elements from mine wastewater by modifying kaolin with phosphoric acid 2023 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 309 Tidskriftsartikel (refereegranskat)abstract Recovery of rare earth elements (REEs) from mine wastewater is essential for maintaining rare earth reserves and sustainable application of REEs. In the present study, we prepared a phosphoric acid modified kaolin (P-K) adsorbent by a simple mechanochemical process for the selective recovery of REEs from rare earth wastewater. The impacts of phosphoric acid dosage, milling duration, initial pH, temperature, initial ion concentration, and adsorbent dosage on the selective adsorption of REEs were investigated. The findings demonstrate that the adsorption of REEs by P-K follows pseudo-second-order kinetic model and the Langmuir isotherm model, and is dominated by chemical adsorption, with a maximum adsorption capacity of 19.82Â mg/g at 50 â„ƒ. Additionally, in an original mine wastewater, the recovery rate of REEs can reach more than 90%, whereas the adsorption rates of calcium, magnesium and, ammonia nitrogen (whose concentration is 18 times that of REEs) are nearly zero, indicating that P-K has extremely high selectivity for REEs. Furthermore, the feedstock solution containing 40Â mg/L of REEs may be concentrated to 3510Â mg/L following enrichment treatment, and 99.9% of the REEs are eluted using a low concentration of hydrochloric acid. The findings illustrate that P-K has a wide range of potential applications in the treatment of rare earth industrial effluents.
31.	Huang, Qi, et al. (författare) Effective photocatalytic sterilization based on composites of Ag/InVO4/BiOBr : Factors, mechanism and application 2023 Ingår i: Separation and Purification Technology. - 1383-5866 .- 1873-3794. ; 327 Tidskriftsartikel (refereegranskat)abstract We hypothesized that photocatalysts with a low band gap could be useful in the sterilization of ceramic tiles in the natural environments of toilets using natural light in those settings. Certain photocatalysts can produce reactive oxygen species (ROS) under light illumination, which in turn are bactericidal. The properties of the BiOBr-containing photocatalysts were tuned by creating junctions and heterostructures with Ag and InVO4 and studied with respect to their bactericidal effect in dispersion. The bactericidal mechanism was studied through experiments in which active species were captured and via electron paramagnetic resonance (EPR) spectroscopy. At an optimal dosage of 0.5 g/L, the Ag/InVO4/BiOBr composite had a sterilization efficacy of 99.9999 % in 30 min under visible light illumination of 1000 W. It retained a sterilization efficacy of 99.999 % after four cycles. Anions such as Cl−, SO42−, and NO3− were shown to have no negative impact on sterilization efficacy. It was shown that the holes in the composite photocatalyst and hydroxyl radicals (·OH) were mechanistically critical for the sterilization. The photocatalysts were also studied in the field in the natural environment of a restroom, where they were loaded on ceramic tiles. Samples were collected from the surface of the ceramic tiles and analyzed for bacterial cultures and microbial diversity. The results were compared in the scope of the sterilization ability of various agents at the microbial level. The ceramic tiles loaded with Ag/InVO4/BiOBr showed the least amount of bacteria on their surfaces, and the microbial community richness was also the lowest.
32.	Jamil, Tarek S., et al. (författare) Enhancement of TiO2 behavior on photocatalytic oxidation of MO dye using TiO2/AC under visible irradiation and sunlight radiation 2012 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 98, s. 270-279 Tidskriftsartikel (refereegranskat)abstract The activated carbon loaded TiO2 photocatalyst was prepared and characterized by FT-IR, scanning electron micrograph (SEM) and X-ray diffraction (XRD). The photocatalytic efficiency of activated carbon loaded TiO2 was evaluated by photocatalytic oxidation of Methyl Orange (MO) dye in aqueous medium using visible and solar light. TiO2/AC exhibited higher photocatalytic oxidation efficiency of MO than that of naked TiO2. The various experimental parameters like initial dye concentration, amount of catalyst and solution pH for efficient dye degradation are investigated. Activity measurements performed under visible light and solar irradiation have shown good results for the photo degradation of MO in aqueous solution. The higher efficiency of TiO2/AC is due to synergy effect of activated carbon. Addition of high adsorption capacity activated carbon to photoactive titanium dioxide in photocatalytic degradation of dyes improves the efficiency of dye mineralization. The present catalysts show high adsorptivity and high photoactivity for the degradation of the MO dye and can be very easily separated from the solution by sedimentation or simple filtration and it can be used repeatedly for MO removal with preservation of its photoactivity.
33.	Jia, Xiuxiu, et al. (författare) Rod-shaped lanthanum oxychloride-decorated porous carbon material for efficient and ultra-fast removal of phosphorus from eutrophic water 2023 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 306 Tidskriftsartikel (refereegranskat)abstract Removal of excess phosphorus (P) from water systems can effectively prevent eutrophication and maintain the ecological balance. In this study, we used a novel freeze-drying thermal oxidation process to prepare a rod-shaped lanthanum oxychloride decorated porous carbon material, polyvinylpyrrolidone /LaOCl (PL). PL showed excellent performance in removing P from water; the preparation method had not been reported previously. Specifically, the adsorption capacity of PL for P was as high as 90.9 mg P/g, and the removal rate was greater than 92.0 % over a wide pH range (2.5–11). Fast adsorption kinetics is an important feature for P removal. The high removal rate of PL for P could be achieved in a short time; that is, more than 97.8 % of the P species could be removed in only 25 min (initial concentration: 20 mg P/L). For water samples from the natural Laoyu River (24 μg P/L), 0.01 g of PL could reduce approximately 53 L of water to below the eutrophication threshold value (20 μg P/L). Furthermore, after five repetitions of the adsorption–desorption process, no significant decrease in the P removal efficiency was observed. The high adsorption capacity, fast adsorption kinetics, and persistent cyclic stability of PL for P in water were attributed to the advanced preparation process, in which freeze-drying ensured the porosity of the adsorbent and the uniformity of LaCl3 distribution; and the subsequent heat treatment created conditions for the generation of LaOCl species with stable adsorption activity. The adsorption mechanism mainly involved ion exchange, electrostatic attraction, and hydrogen bonding. This study provides a theoretical basis for preparing new adsorbing materials of P and technical support for preventing water eutrophication.
34.	Karim, Zoheb, et al. (författare) Upscaled engineered functional microfibrillated cellulose flat sheet membranes for removing charged water pollutants 2022 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 289 Tidskriftsartikel (refereegranskat)abstract Polymeric composite membranes have shown great potential in removing pollutants from water. In the current study, flat sheet functional membranes of microfibrillated cellulose (MFC) with mixed and layered architectures are produced using the up-scaled Dynamic Sheet Former (Formette) in a fully water-based-system, and their potential for the removal of charged impurities is evaluated. The processing of composite membranes is unique in terms of their size (1 m × 20 cm), assembled MFC architectures, controlled/tunable porosity, functional groups densities, and free-standing at high water pressure. Such properties could be difficult to achieve with a lab-scale processing setup. It is shown that the MFC assembly has a direct influence on the pollutant removal efficiency, and again the layered architecture turns out to be a more efficient scavenger of the charged pollutants due to the combined actions of electrostatic interactions, hydrogen bonding, and size exclusion, which are responsible for an ultrafast separation of the impurities through the flat sheets membranes. These experimental results are supported by reactive molecular dynamics simulations of representative model systems that provided possible realistic scenarios at the atomic/molecular scale. All the data confirm the scalability and tunability of the produced MFC-based water cleaning membranes, which show high adsorption capacity, flexibility, hydrolytic stability, and mechanical robustness.
35.	Karimi, Somayeh, et al. (författare) Functionalization of silica membranes for CO2 separation 2020 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 235 Tidskriftsartikel (refereegranskat)abstract Five organic CO2-philic functional groups were incorporated in silica matrixes for preparation of functionalized silica membranes to explore the CO2 separation performance. Chemical groups including acetate, trifluoromethyl, methacrylate, urea and vinyl groups were anchored in the silica network using the co-condensation method.The information from 29Si solid-state NMR and FTIR analyses indicates the successful formation of a covalent bond between functional groups and the silica network. The thickness of the functionalized silica layers was measured by SEM and the thermal stability of the organic groups was determined by thermogravimetric analysis (TGA).The gas permeance and mixed gas selectivity of CO2/N2 was measured in the temperature range of 253–373 K with a feed pressure of 9 bar. A maximum selectivity of as high as 10 was observed for a trifluoromethyl functionalized silica membrane with a CO2 permeance of 5.5 × 10−7 mol s−1 m−2 Pa−1. Permporometry measurements indicated that the contribution of flow through micropores to the total flow for all the functionalized silica membranes varied between 62 and 82%. All membranes were CO2 selective.
36.	Kinnarinen, Teemu, et al. (författare) Local properties of filter cakes formed from pH-adjusted bauxite residue slurries 2018 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 194, s. 1-9 Tidskriftsartikel (refereegranskat)abstract Solid-liquid separation of bauxite residue is a topical issue in the alumina industry, not least due to the great quantity and problematic properties of this highly alkaline residue. The objective of this contribution is to provide deeper knowledge about the solid–liquid separation of pH-adjusted (pH 11) bauxite residue by investigating the local filtration properties of filter cakes produced with a piston press. Two bauxite residue samples having different particle size distribution were investigated. Measured local data of the hydrostatic pressure and solidosity was used together with flow rate data to calculate local specific filtration resistance as well as compressibility data. For the investigated pressure range (0.2–2 MPa) it was found that the residue formed slightly/moderately compressible filter cakes with a specific cake resistance between 5·1011 to 1.5·1012 m/kg. The sodium recovery and final cake solidosity were strongly dependent on the applied pressure, but only to a minor extent on the particle size reduction obtained by the applied mechanical treatment. The filter cakes formed from the mechanically treated samples did, however, display a somewhat higher pressure dependence for the local specific filtration resistance compared to the non-ground samples.
37.	Kinnarinen, Teemu, et al. (författare) The effect of pH adjustment on the properties and pressure filtration characteristics of bauxite residue slurries 2019 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 212, s. 289-298 Tidskriftsartikel (refereegranskat)
38.	Korkmaz, Kivanc, et al. (författare) Separation of Valuable Elements from NiMH Battery Leach Liquor via Antisolvent Precipitation 2020 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 234 Tidskriftsartikel (refereegranskat)abstract Rare earth elements (REE) have been selectively recovered from NiMH battery leach liquors by antisolvent precipitation. The active anode material was leached using sulfuric acid. The REE were then separated from the other elements by precipitation as sulfates after addition of either ethanol or 2-propanol (antisolvent). In a second step, Ni and Co are separated as sulfates by the same technique. The concentration of elements in different acid alcohol mixtures at 25 degrees C and -10 degrees C respectively are presented as a function of time after addition of the alcohol, and the optimum conditions for separation of the REE in pure form are presented. Under optimum conditions, 5.6 mol/L (Organic/Aqueous (O/A) volumetric ratio = 0.7) of 2-propanol at 25 degrees C, 82% of the REE have precipitated 3 h after addition of the antisolvent and the purity is 99.9%.
39.	Krawczyk, Holger, et al. (författare) Impact of prefiltration on membrane performance during isolation of hemicelluloses extracted from wheat bran 2013 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 116, s. 192-198 Tidskriftsartikel (refereegranskat)abstract Hemicelluloses extracted from wheat bran have to be separated from impurities in order to obtain a valuable product at high concentration and purity. A previous investigation showed that separation by ultrafiltration is possible, but the flux was low due to the high viscosity of the solution and the presence of gel-forming substances in the solution. In this investigation the influence of prefiltration on solution viscosity and ultrafiltration performance was investigated. The viscosity of the hemicellulose solution after extraction was considerably reduced with both prefiltration methods tested, leading to a substantial increase in flux during ultrafiltration. The highest flux achieved without pretreatment was about 75 l/m2 h, and was increased to 225 and 440 l/m2 h after dead-end filtration and microfiltration, respectively. However, the loss of hemicelluloses was considerable during microfiltration, but <5% during dead-end filtration. After prefiltration by dead-end filtration, hemicelluloses could be successfully concentrated and purified by ultrafiltration. Eighty percent of the initial volume was removed during concentration at an average flux of 155 l/m2 h. At the same time, the concentration and purity of the hemicelluloses increased from 7.6 g/l and 15% to 31.6 g/l and 31%, respectively. The results obtained in this investigation indicate that dead-end filtration could be a useful form of pretreatment before ultrafiltration when recovering hemicelluloses extracted from wheat bran.
40.	Krawczyk, Holger, et al. (författare) Membrane performance during ultrafiltration of a high-viscosity solution containing hemicelluloses from wheat bran 2011 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 83, s. 144-150 Tidskriftsartikel (refereegranskat)abstract Hemicelluloses isolated from agricultural residues have the potential to replace fossil-based materials in high-value-added applications, provided that cost-efficient isolation processes are developed. In this study, a feed solution containing hemicelluloses extracted from wheat bran with a particular high viscosity was used to study the performance of ultrafiltration for hemicellulose isolation at various operating conditions. The operating parameters affected the flux significantly, but had no influence on the retention of the membrane. The flux was doubled by: (i) increasing the cross-flow velocity from 2 to 5 m/s, (ii) increasing the feed temperature from 60 to 80 degrees C and (iii) decreasing the concentration of the solution by half. The flux increase could mainly be attributed to a decrease in the apparent viscosity of the feed solution. This indicates that low feed viscosity is the key to good membrane performance. The limiting flux during ultrafiltration was reached at the low transmembrane pressure of 0.8 bar, even when the cross-flow velocity and feed temperature were as high as 5 m/s and 80 degrees C, respectively. Low transmembrane pressure is thus preferable during ultrafiltration of solutions similar to that used in the present investigation. The results of this study suggest that ultrafiltration could be a suitable method for the isolation of hemicelluloses from high-viscosity solutions. However, as the operating parameters affect the membrane performance significantly, they must be chosen with care to make the process cost-efficient. (C) 2011 Elsevier B.V. All rights reserved.
41.	Krawczyk, Holger, et al. (författare) Separation of dispersed substances and galactoglucomannan in thermomechanical pulp process water by microfiltration 2011 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 79:1, s. 43-49 Tidskriftsartikel (refereegranskat)abstract Several valuable substances are released from wood during the production of thermomechanical pulp. These substances can be isolated and purified for use as value-added chemicals. The hemicellulose galactoglucomannan (GGM) has attracted a great deal of interest because of its possible applications as an oxygen barrier film in packaging materials, as a hydrogel in biomedical products and as an emulsion stabilizer in food and feed. In order to exploit GGM in pulp mill process water, it must be recovered at a high concentration and high purity. The first step in the purification process is the separation of GGM and dispersed substances. In this work, the influence of membrane pore size, cross-flow velocity and backpulsing on membrane performance during the microfiltration of thermomechanical pulp process water was investigated. The flux of 0.4 and 0.8 mu m membranes was lower than the flux of a 0.2 mu m membrane, and it was not possible to recover the pure water flux of the 0.4 and 0.8 mu m membranes. Increased cross-flow velocity and backpulsing had a positive effect on the flux, but only a minor influence on the retention. The mean molecular mass of GGM in the process water was 9 kg/mol. The retention was therefore expected to be <10%. However, the retention of GGM was >50%, irrespective of the operating conditions. (C) 2011 Elsevier B.V. All rights reserved.
42.	Kullab, Alaa, et al. (författare) Membrane distillation and applications for water purification in thermal cogeneration plants 2011 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 76:3, s. 231-237 Tidskriftsartikel (refereegranskat)abstract Water treatment is an important auxiliary process in all thermal cogeneration plants. In this context membrane distillation (MD) is a novel technology that has potential advantages in: the ability to utilize low-grade heat instead of electricity; reduced sensitivity to fluctuations in pH or salt concentrations. This research is a continuation of a previously conducted theoretical study where the performance of MD-based water treatment was explored via laboratory testing, system simulations of thermodynamic performance, and economic evaluations. The current paper, encompassing field trials, contains details of a test rig deployed at Idbacken Cogeneration Facility (Nykoping, Sweden) with a five-module MD unit capable of producing 1-2 m(3)/day purified water. District heating supply line was employed for heating while municipal water was used for cooling; feed stocks include municipal water and flue gas condensate. A long-term performance evaluation including thorough chemical testing of product water quality is presented. (c) 2010 Elsevier B.V. All rights reserved.
43.	Lakic, Marijana, et al. (författare) Uptake and separation of rare earth elements and late transition metal cations by nanoadsorbent grafted with diamino ligands 2023 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 323 Tidskriftsartikel (refereegranskat)abstract Recycling of magnetic materials based on Rare Earth Elements (REE) is of major interest in the view of growing clean energy production and transportation. One of the major challenges in its realization is the need to separate smaller amounts of Late Transition Metals (LTM) from REE. Hybrid adsorbents are very attractive in finding such a solution. Here, novel silica-based nanoadsorbents were synthesized by grafting the surface of dense silica nanoparticles with a diamino functional ligand grafted via an arene linker to improve selectivity towards LTM. The produced adsorbent materials were characterized using SEM, TEM, AFM, XPS, FTIR, and TGA in its pure form and by DLS in suspension, and tested for the adsorption and separation of LTM (Co2+ and Ni2+) and REE (Sm3+ and Nd3+) in single and mixed solutions. Prepared organo-silica material showed rapid uptake of all tested cations with higher affinity towards LTM. Adsorption capacities reached values of 1.18-1.45 mmol/g for Co2+ and Ni2+, respectively, with a 1:1 metal-to-ligand stoichiometry for Ni cations. Investigation of reusability demonstrated the potential of the prepared materials as an environmentally friendly alternative in specific separation of LTM to conventional separation techniques. Investigations of the molecular structures of the Ni2+ complex with the selected molecular function and of Co3+ with a closely related tris-aminoethyl amine ligand in combination with XPS data for corresponding surface complexes helped explaining the molecular mechanisms for adsorption and desorption of the LTM cations.
44.	Li, Biao, et al. (författare) Thermodynamic study on carbon dioxide absorption in aqueous solutions of choline-based amino acid ionic liquids 2019 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 214, s. 128-138 Tidskriftsartikel (refereegranskat)abstract Five choline-based amino acid ionic liquids ([Cho][AA]s) are prepared by neutralization between choline hydroxide and amino acids with different molecular weight and alkalinity. Solubility of CO2 in 30 wt% aqueous solutions of these five [Cho][AA]s has been measured at temperatures from 303.15 to 333.15 K and pressures up to 7 bar. Based on the zwitterion mechanism, the solubility of CO2 in aqueous [Cho][AA]s solutions is correlated with a reaction equilibrium thermodynamic model (RETM). The corresponding thermodynamic parameters, such as Henry’s law constants, reaction equilibrium constants, and enthalpy of physical dissolution and chemical reaction are all calculated and compared to evaluate the CO2 absorption performance in aqueous solutions of five [Cho][AA]s. Meanwhile, the recyclability of the aqueous solution with 30 wt% [Cho][Lys] has been also investigated.
45.	Li, Changbai, et al. (författare) Separation and concentration of rare earth elements from wastewater using electrodialysis technology 2021 Ingår i: Separation and Purification Technology. - : ELSEVIER. - 1383-5866 .- 1873-3794. ; 254 Tidskriftsartikel (refereegranskat)abstract Rare earth elements (REEs) including Scandium (Sc) are critical raw materials which are greatly needed in the advancement of many modern technologies. Due to the problems associated with the primary extraction of mining ores, the procurement of Sc and REEs from the secondary resources are currently explored adopting the principle of sustainability and circular economy. Herein, for the first time, the Electrodialysis (ED) technology based on electrochemical membrane separation process is successfully applied to separate and concentrate REEs from the diluted aqueous system. The overall performance of ED process in the recovery of Sc3+ ions from the wastewater was assessed by applied current, voltage, feed concentration, feed pH, co-ion competition and the overall energy consumption of the process. The REE recovery using the ED process was subjected to systematic investigations using both chronopotentiometric and chronoamperometric analyses. The results showed that ED process could be very promising in the recovery of Sc3+ ions (similar to 99.52% removal) from the diluted wastewater, consuming the energy of only 0.26 kWh/m(3) when operated at constant voltage mode (Sc3+ concentration of 20 ppm, pH 4, 1 h).
46.	Li, Zhiyang, et al. (författare) Magnetic carbon nanotube modified S-scheme TiO2-x/g-C3N4/CNFe heterojunction coupled with peroxymonosulfate for effective visible-light-driven photodegradation via enhanced interfacial charge separation 2023 Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 308 Tidskriftsartikel (refereegranskat)abstract To remediate water bodies contaminated with organic micropollutants, recyclable and visible-light-driven coupled photocatalysis-peroxymonosulfate (PMS) activation systems were established by synthesizing magnetic-carbon-nanotubes (CNFe) modified TiO2-x/g-C3N4/CNFe (TCNCNFe) S-scheme heterojunction with oxygen vacancies (O-v) by a simple hydrothermal-calcination approach. The introduction of O-v and CNFe enhances the visible-light-harvesting efficiency and the internal electric field across the heterojunction accompanying favorable energy band bending could effectively migrate the photoexcited electrons along the S-scheme mechanism, thus highly suppressing in situ recombination and improving charge separation. Therefore the TCNCNFe-(30-500)/PMS/Vis system achieved 95.4% removal efficiency of atrazine after 30 min irradiation, meanwhile exhibited excellent recyclability without metal ion leaching due to the unique pod-like nanostructure of CNFe. Moreover, the impacts of certain various reaction variables on pollutant removal were explored to evaluate the practical application potential. Interestingly, the biotoxicity of the treated reaction filtrate was significantly alleviated compared to that of ATZ solution. Furthermore, the exploration of photocatalytic reaction mechanism revealed that the dominant reactive oxidizing species contributed in the following order: h(+) > (OH)-O-center dot > O-center dot(2)- > (SO4-)-S-center dot, and the feasible photodegradation pathway of atrazine was presented based on the determined in-termediates. Hence, this research work holds great promise in ecological environment protection using sustainable solar energy.
47.	Lidén, Anna, 1994, et al. (författare) Dewatering microcrystalline cellulose : The influence of ionic strength 2021 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 264 Tidskriftsartikel (refereegranskat)abstract This study investigates the influence of the ionic strength on the dead-end filtration of microcrystalline cellulose (MCC) suspensions in the range of 0.1–1 g/L NaCl, in altering the electrostatic interactions between particles. The formation of larger agglomerates of increasing ionic concentration was observed using Focused Beam Reflectance Measurement (FBRM®). Local filtration properties were investigated as the experimental set-up allowed for measurements of local hydrostatic pressure and solidosity to be made. The results show that the addition of ions decreases both the average and local filtration resistance. The formation of a resistant skin layer was observed for the suspension without the addition of NaCl but was counteracted when ions were added. Furthermore, the ionic strength did not seem to have any notable effect on the structure of the cake in the range 0.15–1.0 g/L NaCl. However, the pressure dependency of the solidosity at lower ionic concentration was higher. The local filtration properties were fitted to semi-empirical relations, which indicated the formation of moderately to highly compressible cakes when NaCl was added.
48.	Ma, Yiqian, et al. (författare) Eutectic freeze crystallization for recovery of NiSO4 and CoSO4 hydrates from sulfate solutions 2022 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 286 Tidskriftsartikel (refereegranskat)abstract In this study, eutectic freeze crystallization (EFC) was investigated to recover NiSO4 and CoSO4 hydrates from aqueous and dilute sulfuric acid solutions of metal sulfates. Binary phase diagrams were established using a combination of thermodynamic modeling and experimental data. The mixed-solvent electrolyte (MSE) model was employed to model solid–liquid phase equilibria. The predicted binary phase diagrams from the model were in good agreement with the experimental results. Experimental eutectic temperatures and eutectic metal sulfate concentrations for the NiSO4-H2O and CoSO4-H2O systems are −3.3 °C and 20.8 wt% and −2.9 °C and 19.3 wt%, respectively. For NiSO4-H2SO4-H2O and CoSO4-H2SO4-H2O systems, the eutectic temperature and eutectic metal sulfate concentration decrease with increasing H2SO4 concentration. Batch experiments were performed to study the EFC of different sulfate solutions, including 25- wt% NiSO4 in H2O, 20- wt% NiSO4 in 0.5 mol/kg H2SO4, 25- wt% CoSO4 in H2O, and 20- wt% CoSO4 in 0.5 mol/kg H2SO4. The results show that controlling the supersaturation allows high-quality ice and salt crystals to be recovered as separate phases under eutectic conditions, with the crystalline salts in the form of heptahydrates. This study shows that EFC can be a promising alternative to evaporative crystallization for recovering NiSO4 and CoSO4 hydrates from sulfate solutions.
49.	Marobhe, Nancy, et al. (författare) Purification of water from small man-made reservoirs by coagulation using purified proteins from Vigna and Parkinsonia seeds 2008 Ingår i: Separation and Purification Technology. - 1383-5866 .- 1873-3794. Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
50.	Matos, Tiago, et al. (författare) Isolation of PCR DNA fragments using Aqueous Two-Phase Systems 2014 Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 122, s. 144-148 Tidskriftsartikel (refereegranskat)abstract Aqueous two-phase systems have frequently been utilized as an efficient bioseparation tool in the downstream processing of different biomolecules. The poly(ethyleneglycol)/poly(acrylate)/salt system, already explored successfully for purification of proteins and plasmid DNA, is here presented as an alternative approach for the isolation of small DNA fragments generated during in vitro DNA polymerase chain reactions. The polymerase chain reaction (PCR) is one of the most versatile laboratory techniques, but the purification of the amplified fragments often represents a major bottleneck. In this work we describe a simple and cost-effective method for isolation of DNA fragments obtained from PCR mixtures. The composition of the aqueous two-phase system in this work has been chosen to precipitate DNA molecules larger than 5000–7000 bp in the interphase, while the PCR products are partitioned very strongly between the phases in a two-step extraction process. In the first step, the DNA is partitioned quantitatively to the poly(ethyleneglycol)-phase. In the second, i.e. the back-extraction step, the DNA is strongly partitioned to a salt-rich phase that contains only low amounts of polymer. This system promotes rapid and high yields of purified small DNA products, less than 4000 bp, without contamination of proteins or large DNA templates present in the reaction mixture.

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