Synergistic influence of hydrophilicity and photocatalysis of bio-TiO2@ZIF-8/PVA-PVDF membrane on high-performance treatment of antibiotic-contaminated water.

Abstract

The menace of antibiotic contamination of water bodies has highlighted the need to develop efficient strategies to effectively remove them from contaminated water for safe discharge. In this study, a high-performance bio-TiO 2 @ZIF-8/PVA-PVDF membrane was developed to effectively remove cefixime, which is a commonly used antibiotic, from contaminated water. Through harnessing the hydrophilicity and photocatalytic capability of the membrane, significant improvements in the membrane’s permeability, CFX removal, and self-cleaning propensity were achieved. Analysis of the bio-TiO 2 @ZIF-8/PVA-PVDF membrane’s hydrophilicity indicates that the water contact angle (WCA) was reduced to 61.00±4.59 o , as compared to the 88.56±2.79 o WCA of the pristine PVDF. The band gap energy (E g ) of the bio-TiO 2 @ZIF-8 composite was narrowed to 2.96eV from 3.25eV obtained for the bio-TiO 2 , which infused the bio-TiO 2 @ZIF-8 modified membrane with photocatalytic ability in the visible light range. The pure water flux (PWF) of the bio-TiO 2 @ZIF-8/PVA-PVDF membrane was 246.50±3.11 L/m 2 h, and the long-term filtration of the CFX-contaminated water demonstrated that the membrane could maintain a stable CFX flux for 78 hrs, while being able to remove up to 99.5% CFX from the wastewater. This notable performance of the bio-TiO 2 @ZIF-8/PVA-PVDF membrane is attributed to the enhanced hydrophilic and photocatalytic capacity of the membrane, which contributed to increasing the membrane’s water affinity and its CFX degradation under visible light. Absorbed CFX on the membrane surface, due to the saturation of the feed solution and CFX blockage of the membrane’s photoactive sites, was noted after the long filtration. However, the absorbed CFX on the membrane was self-cleaned within 1 hr. • A bio-TiO 2 @ZIF-8/PVA-PVDF membrane was developed for the high-performance treatment of cefixime (CFX) contaminated water. • The membrane was modified with hydrophilic and photocatalytic materials. • Integration of hydrophilicity and photocatalysis in the separation process. • Membrane achieved steady CFX flux for 78 hr and 99.5% CFX removal under long-term filtration. • The bio-TiO 2 @ZIF-8 composite is stable in the membrane and there was no notable leaching.