Feasibility of H_2O_2 cleaning for forward osmosis membrane treating landfill leachate

摘要

This study reports landfill leachate treatment by the forward osmosis (FO) process using hydrogen peroxide (H_2O_2) for membrane cleaning. Although chemical cleaning is an effective method for fouling control, it could compromise membrane integrity. Thus, understanding the impact of chemical cleaning on the forward osmosis membrane is essential to improving the membrane performance and lifespan. Preliminary results revealed a flux recovery of 98% in the AL-FS mode (active layer facing feed solution) and 90% in the AL-DS (draw solution faces active layer) using 30% H_2O_2 solution diluted to 3% by pure water. The experimental work investigated the effects of chemical cleaning on the polyamide active and polysulfone support layers since the FO membrane could operate in both orientations. Results revealed that polysulfone support layer was more sensitive to H_2O_2 damage than the polyamide active at a neutral pH. The extended exposure of thin-film composite (TFC) FO membrane to H_2O_2 was investigated, and the active layer tolerated H_2O_2 for 72 h, and the support layer for only 40 h. Extended operation of the TFC FO membrane in the AL-FS based on a combination of physical (hydraulic flushing with DI water) and H_2O_2 was reported, and chemical cleaning with H_2O_2 could still recover 92% of the flux.