Preparation of Nano-SiO2 Modified PA66 Microfiltration Membrane and Treatment of Oily Wastewater

Abstract

With the development of industry, more and more oily wastewater is discharged into the water, which brings great harm to the ecological environment and human health. Membrane separation technology is a very promising technology for oily wastewater treatment. In this experiment, a 1:1 mixed solution of formic acid and dichloromethane (FA/DCM) was used as a solvent to prepare a PA66 microfiltration membrane by evaporation method, and nano-SiO2 was used to modify the PA66 with the determined formula. The apparent morphology, hydrophilicity and mechanical properties of the membrane were characterized by scanning electron microscopy, contact angle test and tensile test, and the effect of treating oily wastewater by microfiltration membrane before and after modification was analyzed. The results show that the mechanical strength and hydrophilicity of the microfiltration membrane are improved after modification by SiO2, and the sewage treatment effect is better. The removal rates of unmodified microfiltration membrane to total suspended solids, chemical oxygen demand and oil concentration are 55%~96%, 50%~85% and 55%~92%; the removal rates of modified microfiltration membrane to total suspended solids, chemical oxygen demand and oil concentration are 98%~99%, 91%~95% and 95%~99%.