Performance Evaluation of Hierarchically Structured Superhydrophobic PVDF Membranes for Heavy Metals Removal via Membrane Distillation.

Heavy metal contamination in water sources is a widespread global concern, particularly in developing nations, with various treatment approaches under extensive scientific investigation. In the present study, we fabricated electrospun composite polyvinylidene fluoride (PVDF) nanofibrous membranes exhibiting hierarchical surface roughness and superhydrophobicity for the removal of heavy metal ions via vacuum membrane distillation (VMD) process. The membranes were prepared by incorporating optimized dosing of silica nanoparticles, followed by a two-step membrane modification approach. These membranes exhibited notable characteristics, including elevated water contact angle (152.8 ± 3.2°), increased liquid entry pressure (127 ± 6 kPa), and reduced average pore size (0.28 ± 0.03 μm). The study demonstrated the efficacy of fabricated membranes in VMD process, specifically for the removal of heavy metals such as arsenic and iron from aqueous solutions. The membrane produced stable permeate flux of 12.7 kg·m−2·h−1 for arsenic-containing feed and 13.2 kg·m−2·h−1 for iron-containing feed, and excellent rejection of >99.9% over a 12-h testing period without any observed wetting of membrane pores. These performance results were compared with those of typical commercial PVDF and pristine electrospun PVDF membranes. Consequently, the developed membrane demonstrated high efficiency and scalability as a water treatment option, showing significant potential for industrial heavy metal removal and the treatment of contaminated groundwater. [ABSTRACT FROM AUTHOR]