Treatment of semiconductor-industry wastewater with the application of ceramic membrane and polymeric membrane

Abstract

There is an abundance of wastewater produced by the semiconductor industry. These wastewaters can be hazardous to the environment if they are discharged without treatment. Furthermore, they contain silicon residues that can be recovered and recycled. Though membrane technologies have the potential to recover the silicon while treating wastewaters, fouling remains a major obstacle. This study thus aims to evaluate the performance of commercial ultrafiltration (UF) ceramic and polymeric membranes in treating three types of semiconductor-industry wastewaters; diluted back grinding wastewater (DBGW), diluted chemical mechanical polishing wastewater (DCMPW), and collection tank wastewater (CTW). One type of ceramic membrane and two types of polymeric membranes were evaluated. The ceramic membrane achieved the highest permeate flux (131.23–308.98 L/m2h) for all three types of wastewaters and was least susceptible to fouling as indicated by the lowest relative flux reduction (RFR) (8.22–57.59%) due to its high porosity, hydrophilicity, and permeability. Irreversible fouling on the ceramic membrane can be mitigated by alkaline cleaning agents to regain flux during DCMPW (96.93%) and DBGW (53.80%) filtration. Acidic agents should be used to regain flux during CTW (79.54%) filtration. Silicon retained on the membrane had a high purity of 39.8 wt% as evidenced by the X-ray spectrometer (EDX) results. The long-term applications of ceramic and polymeric membranes for silicon recovery and wastewater treatment via various cleaning methods were therefore covered in this study.