Effect of crosslinking on organic solvent nanofiltration performance of cellulose membranes

Konca, Kübra
Nanofiltration is a membrane process capable of separation of small molecules and multivalent ions due to their size and/or charge. NF is mainly used in aqueous applications. However, there are many processes that can take advantages of NF in molecules separation dissolved in organic solvents. Main challenge in Organic Solvent Nanofiltration is the limited number of membranes which can withstand a wide range solvents and have stable, predictable separation performance. Cellulose is an alternative polymer that can be used in OSN membranes as it is stable in many organic solvents due to its inter- and intra- molecular hydrogen bonds. Cellulose membranes were fabricated via phase inversion. Solutes used in tests are Bromothymol Blue (neutral,624 Da,=251.1cm3/mole), Cresol Red (neutral,382 Da,=140.1cm3/mole), Rose Bengal (anionic,1017 Da,=241.0cm3/mole) and Brilliant Blue R (anionic,826 Da,=421.3cm3/mole) and Crystal Violet (cationic,407 Da,=253.7cm3/mole). Membranes were crosslinked using two crosslinking agents: glutaraldehyde and 1,2,3,4-butanetetracarboxylic acid. Cellulose membranes was tested with five different solutes.Molecular size is a determining factor for separation of neutral dyes since BTB rejection is higher ratio than CR. BTB and CV rejections are quite close to each other while RB is retained much less than these dyes although molecular size of them are similar. GA-crosslinking did not change solvent permeance and solute rejection. After BTCA-crosslinking, CV rejection decreases slightly while RB rejection increases significantly. Amount of sorbed RB during filtration decreases significantly whereas sorbed CV increases, which may explain increased RB rejection, decreased CV rejection.


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Citation Formats
K. Konca, “Effect of crosslinking on organic solvent nanofiltration performance of cellulose membranes,” M.S. - Master of Science, Middle East Technical University, 2018.