Photocatalytic TiO2 incorporated PVDF-co-HFP UV-cleaning mixed matrix membranes for effective removal of dyes from synthetic wastewater system via membrane distillation

We report membranes with UV-cleaning properties by incorporating photocatalytic porous TiO2 sheets (PTS) (0-5 wt%) in the PVDF-co-HFP matrix. PTS were synthesized using controllable large-scale synthesis protocols by spray drying followed by calcination. These membranes were assessed for the removal of Congo red (CR) and methylene blue (MB) from synthetic textile industry wastewater system (CR: 100 mg l(-1) + MB: 100 mg l(-1) + 4% NaCl) via direct contact membrane distillation (DCMD) configuration and their UV-cleaning properties. The PTS were characterized by FE-SEM, TEM and different spectral techniques, while membranes were assessed by surface morphology (FE-SEM, AFM), thermal stability, hydrophobicity, permeate flux, and dye rejection performance. The surface morphology study of PTS revealed its micro-sized sheet with the porous surface. With increased PTS concentration in the membrane matrix, the flux and dye rejection of mixed matrix membranes improved. Suitably optimized PT3 (3 wt% PTS in PVDF-co-HFP matrix) membrane showed similar to 100% dye removal efficiency (MB and CR) and 6.1 kg m(-2) h(-1) vapour flux. Long run (5 days) DCMD experiments showed >91% flux recovery ratio (FRR) after UV-cleaning. This study suggests the suitability of the prepared membranes to treat textile wastewater and their UV-cleaning properties.

Automated summary

Membranes with UV-cleaning properties were prepared by incorporating photocatalytic porous TiO2 sheets (PTS) into the PVDF-co-HFP matrix, showing great potential for treating textile wastewater. The optimized membrane exhibited excellent dye removal efficiency and vapor flux.