Construction of Renewable Porous Nanofiltration Membrane by Amino Cyclodextrin for the Treatment of High Salinity Textile Wastewater

The discharge of textile wastewater containing pollutants could cause serious environmental pollution. The use of loose nanofiltration membranes(LNF) to separate dyes and salts from textile wastewater had great significance. A dense surface layer was produced by traditional piperazine(PIP) monomer undergo interfacial polymerization(IP) reaction on membrane surface, which not only reduced the water flux of membrane but also reduced the selectivity of salts and dyes. Therefore, this study used β-cyclodextrin(β-CD-AAm) as a novel porous aqueous monomer for IP reaction, and prepared a novel membrane for filtering textile wastewater. Due to the porous structure of β-CD-AAm, it could separate dyes and salts, increase water flux and mechanical property. Additionally, azobenzene was added to the bowl like structure of β-CD-AAm to endow the nanofiltration membrane with renewable functions. The permeability increased from 27 L/m2·h to 75L/m2·h, and increased by 177.8%. It also increased the retention rate of methyl blue from 95.9% to 98.9%, and decreased the rejection rate of Na2SO4 from 22.3% to 10.1%, the separation selectivity a of dye and salts increased from 35.2 to 82.7. The effects of porous aqueous phase monomer β-CD-AAm on diffusion speed of aqueous phase was demonstrated via ultraviolet light test and mean square displacement (MSD), demonstrating the influence of β-CD-AAm on the polyamide layer structure and property of the membrane. This provides a new approach for using new aqueous monomers to produce porous nanofiltration membranes for the treatment effect, recover the high salt textile wastewater, and promote the green development of dye industry.