Arsenic removal in groundwater by UV based photocatalysis with immobilized ZnO-nanoparticle on ceramic plate

Abstract

Arsenic (As) is naturally present in the lithosphere (earth crusts, soil, rock and sediment) and hydrosphere (surface water, aquifers, deep wells, and oceans). It can exist in the groundwater from the weathering process of rocks which caused a high concentration of As in groundwater and increased risk of health when consuming the contaminated water. To reduce this risk, As standard in drinking water was set by WHO and Indonesia’s drinking water standard of 0,01 mg/L. In this study, arsenic contaminated water treatment is carried out using advanced oxidation process ZnO/UV photocatalytic. The immobilized ZnO nanoparticle catalyst coated onto a ceramic plate by dip coating method. Kinetic study was performed in a batch reactor with artificial ground water using sodium arsenite (NaAsO2) at pH 4, 7, and 10 with initial concentration of arsenic set aside at 1 mg/L, 3 mg/L, and 5 mg/L. ZnO was irradiated by UV-C light (λ = 265 nm) for photocatalysis of arsenite As (III) oxidation into arsenate As(V) for 2 hours. Removal efficiency using ZnO/UV photocatalysis for arsenic total (99,99% of 1 mg/L, 83,25% of 3 mg/L, and 51,82% of 5 mg/L) and for As (III) (99,99% of 1 mg/L, 96,34% of 3 mg/L, and 77,73% of 5 mg/L) in acidic condition. Data analysis in the study used the AAS method to calculate the value of the total arsenic concentration tested and the colorimetric spectrophotometer method to calculate the value of As (III) and to determine the absorb of ceramic plate coated ZnO. The characteristics of ceramic plate immobilized ZnO nanoparticles is analyzed by SEM-EDS. ZnO nanoparticles coated onto ceramic plate surfaces is 80,65% (5,5 mg/cm2). This study was conducted to determine the optimum dose of catalyst used to oxidize As (III) to As (V) and the capacity of the immobilized ceramic plate catalyst in adsorbing arsenic compounds in solution which was then presented in the final research report.