Preparation and Cr (VI) Removal Performance of a New Positively Charged PVC Microfiltration Membrane

Poly (vinyl chloride co dimethyl aminoethyl methacrylate) (PVD) and polyvinyl chloride (PVC) were blended, and then the tertiary amine groups of PVD in the casting solution were quaternized in situ with methyl iodide (CH₃I) at 60. A new strongly charged positive PVC/PVD (M1) microfiltration membrane was prepared by non solvent induced phase transformation (NIPS), and PVC (M0) microfiltration membrane was prepared and compared with it. The membrane performance parameters such as morphology, pore size, charge, hydrophilicity and pure water flux of M0 and M1 were characterized. The cationic surfactant Octadecyltrimethylammonium chloride (STAC) micelle enhanced filtration was used to remove trace Cr⁶⁺(Cr₂O₇^2-) from the solution. The effects of Cr⁶⁺ concentration, pH value and sodium chloride (NaCl) concentration on the interception performance were investigated. The results show that the rejection rate of Cr⁶⁺ removal by M1 membrane micelle enhancement is close to 100%. When the mass ratio of Cr⁶⁺/STAC is greater than 0.478, the rejection rate of Cr⁶⁺ removal by M1 decreases with the increase of Cr⁶⁺ concentration; PH value has little effect on the retention of Cr⁶⁺ by M1; High concentration of NaCl reduced the rejection rate of Cr⁶⁺ by M1. M1 microfiltration membrane has potential development prospects in the treatment of wastewater containing Cr⁶⁺.