Fabrication of novel carboxybetaine zwitterionic copolymer modified membrane applied for oil/water mixtures
摘要
Oily wastewater is increasingly affecting the earth’s ecological environment upon which human beings depend for survival. Membrane separation is an environmentally friendly, energy-saving and highly efficient separation method. In the work, one novel carboxybetaine zwitterionic monomer (CAC) were synthesized and characterized. The suspension was composed of a copolymer (P(CAC-co-HEA)) made by 2-hydroxyethyl acrylate and CAC, tetraethyl silicate, and nano-silica was employed for the dip-coating treatment of a 400-mesh stainless steel mesh (SSM). The modified SSM exhibits outstanding superhydrophilicity and underwater superoleophobicity. It can separate various kinds of oily wastewater with more than 99.96% separation efficiencies. Its separation water flux for mixture of petroleum ether and water reaches up to 230,000 L m−2 h−1. When the modified membranes had been successively immersed for seven days in acidic (pH 1) and 3.5% (wt.%) NaCl solution, respectively, they can still effectively separate oil/water mixtures with more than 180,000 L m−2 h−1 water flux and with a separation efficiency over 99.95% even if two membranes carried out 50 cycles of separation. The simple and facile preparation method is especially suitable for large-scale practical industrial applications.