Removal of sulfamethoxazole and tetracycline in water using polyvinylidene fluoride membrane modified with polyethyleneimine

Abstract

With the increasing impact of antibiotics on the environment, membrane separation technology has been widely used to treat antibiotics in water environment. The poor hydrophilicity of poly - vinylidene fluoride (PVDF) membrane leads to the problems of low water flux and easy surface pollution during membrane separation. In this study, the surface of PVDF base film was modi - fied by polyethyleneimine (PEI). The influence of modified membrane on the retention capacity, anti-fouling property and operation characteristics of sulfamethoxazole (SMX) and tetracycline (TC) was investigated. The effect of PEI concentration on the comprehensive performance of pure water flux and antibiotic rejection was investigated by changing the molecular weight of PEI. The results showed that the comprehensive performance was relatively best when the molecular weight of PEI was 10,000 Da (P-10K). It could remove 57.5% and 30% of SMX and TC from the simulated water samples, and 88.2% and 62.4% of SMX and TC from the actual river water samples. However, it is also accompanied by a large degree of membrane fouling, resulting in a decrease in membrane separation performance. After the rotation test of single factor variables, it was found that the cat - ion strength and humic acid concentration had the greatest influence on the flux and antibiotic retention of the modified membrane through the steric hindrance effect. In the anti-fouling per - formance test, the membrane flux can be restored to 85% and 92.3% of the initial flux after acid washing and alkali washing, indicating that the anti-fouling performance of the PVDF membrane after surface cross-linking modification is improved.