(545ag) Appilcation of Polysaccharide Derivatives As Novel Draw Solutes in Forward Osmosis for Protein Concentration

In this study, a series of anionic polyelectrolytes, sodium carboxymethyl dextrans with different molecular weights (CM-dextran-1000/5000/20000), are facilely synthesized via a one-step reaction and employed as novel draw solutes in FO process. Various characterizations (FTIR, NMR, conductivity titration and cytotoxicity test) are conducted to confirm the chemical structure, substitution degree and toxicity of the synthesized CM-dextrans. Effects of the concentration, molecular weight and substitution degree on the physicochemical properties (solubility, relative viscosity, conductivity and osmotic pressure) of CM-dextrans as well as their corresponding FO performance are investigated systematically. Compared with 1 M NaCl draw solution, 40 wt% CM-dextran-1000 draw solution shows a higher FO water flux (24.9 LMH) and a much lower reverse solute flux (0.97 gMH) in PRO mode. The recyclability of the diluted CM-dextran draw solutions is evaluated by an ultrafiltration process. Furthermore, the developed CM-dextrans with low reverse solute diffusion and nontoxicity can be potentially employed as promising draw solutes for the protein concentration via FO.