A high performance of polyvinylidene fluoride membrane modified with vanilin for humic acid removal

Abstract

The presence of humic acid in surface water poses a challenge to water treatment processes. Furthermore, membrane fouling induced by humic acid is facilitated by the hydrophobic nature of the membrane material. In response, this study explores the use of hydrophilic additives, specifically vanillin, to modify the properties and performances of polyvinylidene fluoride (PVDF) membranes. Four different types of membrane flat sheets were prepared by non-solvent induced phase method. The modification of the membrane was carried out by blending vanillin (at a concentration of 0–5% w/w) with PVDF polymer. The results show that the incorporation of 3% w/w vanillin has a positive influence, increasing membrane hydrophilicity, porosity, and pore number and size. As a result, the permeate performance of the PVDF-vanillin membrane showed a significant improvement, with an increase in water flux to 30.9 Lm−2h−1, a humic acid rejection of 81.78%, and a high flux recovery ratio (FRR) of 108.68%. Adverse side effects were observed beyond the optimal concentration of 3% w/w vanillin. In conclusion, this study provides valuable insights for the development of PVDF membranes tailored for humic acid removal and organic fouling reduction.

Keywords

• Polyvinylidene fluoride membrane
• Vanillin
• Humic acid removal
• Hydrophilic
• Fouling