| 1. |
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34th EMS Summer School : Membranes in Biorefineries
- 2017
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Proceedings (redaktörskap) (refereegranskat)abstract
- The EMS Summer School “Membranes in Biorefineries” is related to Annex XVII of the Industrial Energy Related Technologies and Systems (IETS)Implementing Agreement: “Membrane Filtration for Energy-efficient Separation of Lignocellulosic Biomass Components” co-ordinated by the Department of Chemical Engineering at Lund University, Sweden.The IETS Implementing Agreement is an initiative within IEA (International Energy Agency). The mission of IETS is to foster international co-operation among OECD and non-OECD countries for accelerated research and technology development of industrial energy-related technologies and systems. In doing so, IETS seeks to enhance knowledge of cost-effective new industrial technologies and system layouts that enable increase productivity and better product quality while improving energy efficiency and sustainability.
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| 2. |
- Al-Rudainy, Basel, et al.
(författare)
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Galactoglucomannan Recovery with Hydrophilic and Hydrophobic Membranes: Process Performance and Cost Estimations
- 2019
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Ingår i: Membranes. - : MDPI AG. - 2077-0375. ; 9:8
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we compared the GR51PP (hydrophobic/polysulfone) membrane with a series of hydrophilic (regenerated cellulose) membranes with the aim of increasing the retention of products and decreasing membrane fouling. The raw material used was a sodium-based spent sulfite liquor from the sulfite pulping process of spruce and pine. The results show that the hydrophilic membranes were superior to the hydrophobic membranes in terms of higher fluxes (up to twice the magnitude), higher product retentions and less fouling (up to five times lower fouling). The fouling was probably caused by pore blocking as observed in earlier studies. However, the hydrophilic membranes had a lower affinity for lignin, which was indicated by the lower retention and fouling. This also resulted in a separation degree, which was higher compared with the hydrophobic membrane, thus yielding a higher galactoglucomannan (GGM) purity. 2D HSQC NMR results show that no major structural differences were present in the hydrophilic and hydrophobic retentates. A techno-economical evaluation resulted in the RC70PP being chosen as the most cost-efficient membrane in terms of flux and product recovery.
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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- Bildyukevich, Alexandr V., et al.
(författare)
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Effect of molecular weight of polyacrylic acid (PAA) on polyethersulfone membrane structure and performance
- 2019
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Ingår i: ; , s. 88-88
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Konferensbidrag (refereegranskat)abstract
- The novel method of modification of polyethersulfone (PES) ultrafiltration membranes is proposed. This method involves the use of aqueous solutions of polyacrylic acid (PAA) of different molecular weights (Mn=5.1×103 g·mol–1, Mn=490×103 g·mol–1) as a coagulant in non-solvent induced phase inversion process (NIPS). Addition of PAA (0.05–1.5 wt%) to the coagulation bath leads to marked changes in permeability and hydrophilicity of the surface of membrane selective layer. When the coagulation bath contains 0.5 wt% of PAA (Mn=5.1×103 g·mol–1) the rejection coefficient for polyvinulpyrrolidone (PVP К-30, Mn=40 kDa) decreases from 95% (for pristine PES membrane) to 80% (for membrane modified by PAA) and pure water flux (PWF) increases from 55 to 150 l·m-2·h-1. The presence of 0.1 wt% PAA (Mn=490×103 g·mol–1) in the coagulation bath results in an increase in PWF up to 220 l·m-2·h-1 and a decrease in rejection coefficient down to 35%. Water contact angles of the surface of the selective layer of modified membranes decreased down to 33o, for membranes, modified with PAA of higher molecular weights, and down to 43o for for membranes, modified by PAA with lower molecular weight (Mn=5.1×103 g·mol–1). The presence of PAA on the surface of PES membranes is confirmed by the FTIR spectroscopy. The membranes obtained by using PAA solution were pH-sensitive and pH-reversible, while the PWF of the initial membranes did not respond to the pH of feed solution. The SEM analysis of the structure of the membranes reveals marked difference in the morphology along cross section between the pristine and modified membranes. The suppression of macrovoids formation in the supporting layer of membrane with an increase in the concentration of PAA in the coagulation bath was noted. Fouling resistance behavior was studied using bovine serum albumin (BSA) solution in phosphate buffer. It was found that PAA addition to the coagulation bath enhances the fouling resistance of the modified membranes. The best fouling resistance with respect to BSA fouling is observed for the membranes with maximum hydrophilicity.This work was supported by the Belarusian Republican Foundation for Fundamental Research, Grant No. X18MС-018 and STINT Grant no. IB 2017-7377.
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| 7. |
- 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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| 8. |
- 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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| 9. |
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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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| 10. |
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