Preparation of hydrophilic PVDF membrane via blending with Fe3O4 nanoparticles and PVA for improved membrane performance in BTEX removal from wastewater

Abstract

The recurring cases of the presence of organic contaminants, which include benzene, toluene, ethylbenzene, and xylene (denoted as BTEX) in our water bodies, have reaffirmed the need for continuous development of new strategies for proper BTEX wastewater treatment before discharge. In this study, biogenic-synthesized iron oxide nanoparticles (Fe₃O₄-NPs) and polyvinyl alcohol (PVA) were utilized as hydrophilic modifiers to mitigate the non-specific hydrophobic interaction of BTEX and polyvinylidene fluoride (PVDF) membrane to improve membrane performance. Chemical compositional analysis of the membrane confirmed that hydrophilic functional groups were infused into the membrane due to blending the Fe₃O₄-NPs and PVA into the PVDF membrane. The PVA-Fe₃O₄-PVDF membrane displayed improved hydrophilicity as indicated by its water contact angle (WCA) of 40.5°. Consequently, its anti-fouling performance was enhanced. The total fouling ratio (R_t) of the pristine PVDF was 0.48, of which 0.25 and 0.23 are irreversible (R_ir) and reversible (R_r) fouling, respectively. This was reduced to an R_t of 0.18 for the modified membrane, and the irreversible fouling declined to 0.02, while 0.16 of the fouling is reversible. The porosity of the modified membrane was also enhanced, resulting in the pure water flux of the membrane improving from 165.3 Lm⁻²h⁻¹ (pristine membrane) to 313.7 Lm⁻²h⁻¹ (modified membrane). With the Fe₃O₄-NPs acting as nanofillers in the modified membrane matrix, the enhanced membrane porosity did not adversely affect its rejection efficiency. The test of the stability of the modified membrane under long-term filtration revealed that the membrane has good and improved operational stability compared to the pristine membrane.