Reduction of Iron (Fe) in Environmental Engineering Chemistry Laboratory Liquid Waste Using Membrane Distillation

Abstract

Laboratory wastewater generated from chemical analysis activities contains hazardous pollutants that require proper treatment before discharge. Preliminary analysis of wastewater from the Environmental Engineering Chemistry Laboratory, Universitas PGRI Adi Buana Surabaya, indicated that the iron (Fe) concentration exceeded the maximum permissible limit specified in the Indonesian Minister of Health Regulation No. 2 of 2023 concerning Environmental Health. This study aimed to evaluate the effectiveness of vacuum membrane distillation technology in reducing Fe concentration using different membrane materials and pore sizes. Three membrane configurations were investigated: (A) Polytetrafluoroethylene (PTFE) with a pore size of 0.22 µm, (B) PTFE with a pore size of 0.45 µm, and (C) Polyvinylidene fluoride (PVDF) with a pore size of 0.45 µm. The experimental results demonstrated that both PTFE membranes exhibited superior performance, achieving Fe removal efficiencies of 75.4% and 74.6% for the 0.22 µm and 0.45 µm membranes, respectively. These treatments reduced the initial Fe concentration of approximately 0.4 ppm to 0.10–0.12 ppm, meeting the maximum allowable concentration of 0.2 ppm established by the Indonesian Minister of Health Regulation No. 2 of 2023. In comparison, the PVDF membrane showed a lower removal efficiency of 50.5%, producing a final Fe concentration of 0.215 ppm, slightly above the regulatory limit. These findings indicate that PTFE membranes, particularly the 0.22 µm membrane, are more effective than PVDF membranes for Fe removal and demonstrate the potential of vacuum membrane distillation as an environmentally friendly technology for treating laboratory wastewater.