| 1. |
- Battestini Vives, Mariona, et al.
(författare)
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Low-Molecular-Weight Lignin Recovery with Nanofiltration in the Kraft Pulping Process
- 2022
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Ingår i: Membranes. - : MDPI AG. - 2077-0375. ; 12:3, s. 310-310
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Tidskriftsartikel (refereegranskat)abstract
- Kraft lignin is an underutilized resource from the pulp and paper industry with the potential of being a key raw material for renewable fuels and chemicals. The separation of high-molecular-weight lignin from black liquor by ultrafiltration has been widely investigated, while the permeate containing low-molecular-weight lignin has received little attention. Nanofiltration can concentrate the low-molecular-weight lignin. This work, therefore, evaluates nanofiltration for the separation and concentration of low-molecular-weight lignin from the ultrafiltration permeate. For this study, eight flat polymeric sheet membranes and one polymeric hollow fiber membrane, with molecular weight cut-offs ranging from 100 to 2000 Da, were tested. A parametric study was conducted at 50 °C, 2.5–35 bar, and crossflow velocity of 0.3–0.5 m/s. At a transmembrane pressure of 35 bar, the best performing membranes were NF090801, with 90% lignin retention and 37 L/m2·h, and SelRO MPF-36, with 84% lignin retention and 72 L/m2·h. The other membranes showed either very high lignin retention with a very low flux or a high flux with retention lower than 80%. Concentration studies were performed with the two selected membranes at conditions (A) 50 °C and 35 bar and (B) 70 °C and 15 bar. The NF090801 membrane had the highest flux and lignin retention during the concentration studies. Overall, it was shown that the nanofiltration process is able to produce a concentrated lignin fraction, which can be either used to produce valuable chemicals or used to make lignin oil.
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| 2. |
- Battestini Vives, Mariona, et al.
(författare)
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Recovery and Characterization of Low-Molecular-Weight Lignin from Ultrafiltered Kraft Black Liquor
- 2022
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Ingår i: <em>10<sup>th</sup> Nordic Wood Biorefinery Conference</em>. - Helsinki. - 9789513887728 ; , s. 218-219
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Kraft lignin is an aromatic polymer found in black liquor, a side stream of the kraft pulping industry.Usually, lignin is burned in the recovery boiler of the pulp mill as a fuel for energy generation. However,lignin has great potential as a raw material for the production of fossil-free fuels, chemicals, andmaterials. Membrane filtration has been studied in the last decades as a key separation method torecover lignin from black liquor. Further studies to concentrate lignin using membrane filtration arerequired, as well as characterization of the resulting lignin fractions for the development of moleculartailored lignin-based applications.In the present work, nanofiltration (NF) was used to concentrate and recover the low-molecularweightlignin obtained from the permeate of ultrafiltration of kraft black liquor. The concentration wasperformed using a NF090801 polymeric NF membrane (SolSep) with a molecular weight cut-off of 350Da. A transmembrane pressure of 25 bar and 50 °C during the filtration increased the lignin contentfrom 27 to 52 g/l, whereas a transmembrane pressure of 15 bar and 70 °C gave an increase from 18 to45 g/l in lignin content. The lignin fraction recovered in the retentate of the NF step was analyzed bysize-exclusion chromatography to ascertain the molecular weight of the lignin. Moreover, Fouriertransform infrared spectroscopy and thermogravimetric analysis were carried out to evaluate thethermal properties and functionalities of the obtained fractions.
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| 3. |
- Bildyukevich, Alexandr V., et al.
(författare)
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Correlation between membrane surface properties, polymer nature and fouling in skim milk ultrafiltration
- 2020
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757. ; 605
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Tidskriftsartikel (refereegranskat)abstract
- The fouling of the membranes in skim milk ultrafiltration with the nominal molecular weight cut-off (MWCO) of 100 kDa fabricated from different polymers (polysulfone (PSF), polysulfonamide (PSA), aromatic polyamide (PA), polyacrylonitrile (PAN), cellulose acetate (CA) and regenerated cellulose (RC)) was studied. The membrane structure and physical-chemical properties of the selective layer were analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle (θ, °) measurements, free surface energy measurements and bovine serum albumin (BSA) adsorption. Additionally, the flux of the skim milk at the constant product concentration, protein adsorption, resistance of the gel layer of the membranes were determined. It was found that according to the decrease in water contact angle of the membrane selective layers membranes can be arranged in the series as follows: PSF > PSA > PA > PAN > CA > RC. It was revealed that there was no direct correlation between the membrane hydrophilicity and the protein adsorption. It was noted, that the studied membranes featured significantly different hydraulic resistances of the protein gel-layer, which can be considered as a secondary dynamic membrane. Comparison of the parameters – water contact angle and polar component of the free surface energy of the membrane selective layer, and normalized dipole moment of the membrane polymers - with the adsorption values of the proteins during ultrafiltration proves that the protein adsorption to the membrane surface increases with an increase in hydrophobicity and polarity of the membrane. The high protein adsorption by the moderately hydrophilic PAN membrane is due to the contribution of the high normalized dipole moment of the polymer. In the case of the polar RC-100 membrane, the influence of the membrane polarity was shown to be counter-balanced by its high hydrophilicity. The study highlights the impact of the physical-chemical properties and structure of the membrane on the protein gel-layer and thus their importance in membrane fouling control in dairy applications.
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| 4. |
- Burts, Katsiaryna S., et al.
(författare)
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Development of Antifouling Polysulfone Membranes by Synergistic Modification with Two Different Additives in Casting Solution and Coagulation Bath: Synperonic F108 and Polyacrylic Acid
- 2022
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- This study deals with the development of antifouling ultrafiltration membranes based on polysulfone (PSF) for wastewater treatment and the concentration and purification of hemicellulose and lignin in the pulp and paper industry. The efficient simple and reproducible technique of PSF membrane modification to increase antifouling performance by simultaneous addition of triblock copolymer polyethylene glycol-polypropylene glycol-polyethylene glycol (Synperonic F108, Mn =14 × 103 g mol−1) to the casting solution and addition of polyacrylic acid (PAA, Mn = 250 × 103 g mol−1) to the coagulation bath is proposed for the first time. The effect of the PAA concentration in the aqueous solution on the PSF/Synperonic F108 membrane structure, surface characteristics, performance, and antifouling stability was investigated. PAA concentrations were varied from 0.35 to 2.0 wt.%. Membrane composition, structure, and topology were investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The addition of PAA into the coagulation bath was revealed to cause the formation of a thicker and denser selective layer with decreasing its pore size and porosity; according to the structural characterization, an interpolymer complex of the two additives was formed on the surface of the PSF membrane. Hydrophilicity of the membrane selective layer surface was shown to increase significantly. The selective layer surface charge was found to become more negative in comparison to the reference membrane. It was shown that PSF/Synperonic F108/PAA membranes are characterized by better antifouling performance in ultrafiltration of humic acid solution and thermomechanical pulp mill (ThMP) process water. Membrane modification with PAA results in higher ThMP process water flux, fouling recovery ratio, and hemicellulose and total lignin rejection compared to the reference PSF/Synperonic F108 membrane. This suggests the possibility of applying the developed membranes for hemicellulose concentration and purification.
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| 5. |
- Burts, K.S., et al.
(författare)
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Development of polysulfone ultrafiltration membranes with enhanced antifouling performance for the valorisation of side streams in the pulp and paper industry
- 2022
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757. ; 632
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Tidskriftsartikel (refereegranskat)abstract
- One-stage method of polysulfone (PSf) membrane modification by the addition of polyacrylic acid (PAA, Mn = 250 kg·mol−1) to the coagulation bath during membrane preparation via non-solvent induced phase separation (NIPS) was proposed. The effect of PAA concentration on the membrane structure, hydrophilicity, zeta potential, separation performance and antifouling stability in ultrafiltration of lysozyme, polyvinylpyrrolidone (PVP K-30, Mn = 40 kg mol−1) and humic acid model solutions as well as thermomechanical pulp mill process (ThMP) water was studied. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), measurements of the tangential flow streaming potential and water contact angle were used for membrane characterization. It was found that addition of PAA into coagulation bath resulted in decreasing pore size and porosity of the selective layer as well as the formation of a thicker and denser selective layer. Water contact angle of the modified membranes was found to decrease significantly and zeta potential of the selective layer was shown to become more negative in the studied pH range 3–10, all compared to the reference membrane. It was revealed that pure water flux (PWF) decreased and lysozyme and PVP K-30 rejection increased with the increase in PAA concentration in the coagulation bath. It was found that membranes modified with PAA demonstrated better antifouling stability in ultrafiltration of humic acid solution and ThMP process water. Modified membranes were found to have higher flux, fouling recovery ratio and hemicelluloses rejection in ThMP process water ultrafiltration compared to the reference PSf membrane that allows application of these membranes for hemicelluloses concentration and purification.
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| 6. |
-
Current Trends and Future Developments on (Bio-) Membranes
- 2024
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- Current Trends and Future Developments on (Bio-) Membranes: Engineering with Membranes discusses various aspects of membrane engineering. This includes, but is not limited to, the role of membranes in food production, treatment and recovery, their applications in electrochemical processes and devices, in drug delivery and in ionic materials, such as salts, acids and bases, recovery. In addition, this book approaches the above topics in a different angle than the existing publications, i.e., reviews technical difficulties, environmental challenges and economic analysis. Membranes are one of the technologies which can affect various aspects of engineering dealing with feeds and products. Membranes demonstrate selective purifying properties, hence, membranes can help in the removal of various pollutants onsite and without the need of adding extra units and apparatuses. Besides that, membranes help reactions shift forward and make the whole process more efficient.
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| 7. |
- Elhamarnah, Yousef, et al.
(författare)
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Investigating the impact of stormwater fouling on polysulfone ultrafiltration membranes modified with deep eutectic solvents
- 2023
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Ingår i: Journal of Water Process Engineering. - 2214-7144. ; 56, s. 104362-104362
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we evaluate the performance of modified polysulfone (PSF) ultrafiltration (UF) membranes, which incorporate deep eutectic solvents (DES), in treating stormwater laden with natural organic matter e.g. chemical oxygen demand (COD) and total suspended solids (TSS). We also aim to understand how these organic substances, e.g. COD, TSS, from the water source contribute to the fouling of the synthesized membranes. PSF membranes were synthesized using a non-solvent induced phase separation technique and integrated with varying concentrations of ChCl:FR (Choline Chloride: D-(−)-Fructose) 1:1 DES. The surface and porous structures of the membranes were characterized through Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), contact angle measurements, scanning electron microscopy (SEM), and mechanical testing. The UF performance of these membranes was assessed and compared with different commercially available UF flat sheet membranes in terms of pure water permeability and antifouling behavior against collected stormwater from a sedimentation pond. Furthermore, the study evaluated the quality of the permeate based on parameters such as COD, turbidity, TSS, pH, and conductivity and compared the permeate quality of a pilot-scale ceramic UF membrane unit. The findings indicate that the inclusion of DES in the polysulfone membrane structure enhances the membranes' antifouling properties and permeability. This research offers valuable insights into the role of DES in the formation of polysulfone UF membranes and their potential for practical use e.g. sedimented stormwater.
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| 8. |
- Essalhi, Mohamed, et al.
(författare)
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The potential of salinity gradient energy based on natural and anthropogenic resources in Sweden
- 2023
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Ingår i: Renewable energy. - : Elsevier. - 0960-1481 .- 1879-0682. ; 215
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents assessment of natural and anthropogenic sources of blue energy within Swedish territory to identify suitable spots for implementing new projects. The natural energy potential of salinity gradients was found to be higher in southwest Sweden, and a national energy resource potential of 2610.6 MW from seawater/river water mixing will be reduced to a technical potential ranging from 1044.3 MW to 1825.4 MW considering technical and environmental constraints. It has been found that the theoretical extractable energy potential in Sweden is equivalent to 13% of the total electricity consumption and 6.2% of the total final energy consumption by energy commodities.Anthropogenic water sources were also highlighted as promising low and high-concentration solutions for SGE extraction. Gotland was identified as an attractive location for generating salinity gradient power. The total salinity gradient power obtainable by mixing municipal wastewater with seawater in Sweden was estimated to be 11.8 MW. The most promising site for this process was determined to be Gryaab AB Ryaverket in Gothenburg, which accounted for 45.8% of the total national potential from anthropogenic sources.
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| 9. |
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| 10. |
- Hliavitskaya, Tatsiana, et al.
(författare)
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Development of antifouling ultrafiltration PES membranes for concentration of hemicellulose
- 2020
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 138:17
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Tidskriftsartikel (refereegranskat)abstract
- A new approach for one‐stage facile membrane modification during non‐solvent induced phase separation (NIPS)‐process is proposed. The novelty of this study is that cheap and commercially available anionic high molecular polyacrylamide‐based flocculant (AHMPF) is applied for the first time as an additive to coagulation bath (CB). The series of polyethersulfone membranes were prepared using 0.05–0.3 wt% AHMPF aqueous solution as CB at different temperatures (25–50°C) via NIPS. The effect of AHMPF concentration on the structure, composition and hydrophilicity of membranes was investigated. The separation and antifouling performance were evaluated during filtration of bovine serum albumin (BSA) solution and thermomechanical pulp mills process water (ThMP) in order to concentrate hemicellulose. The successful immobilization of AHMPF into the structure of membranes selective layer (not bottom layer) was confirmed by FTIR spectroscopy. It was established that despite the similar rejection of hemicellulose (88.8–93%) and lignin (20–21.4), modified membranes demonstrate 3–8 times higher flux and 2 times higher FRR (43.8% for reference membrane and 86.5% for modified one) in ThMP ultrafiltration. The developed membrane was found to be highly efficient in hemicellulose concentration and purification in pulp industry.
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