Optimization of the electro-photocatalytic process for the removal of formaldehyde from water using the Taguchi model

The most significant environmental issue in many nations across the world is industrial wastewater contamination with formaldehyde (a priority pollutant). Any natural water that has had industrial effluent discharged into with formaldehyde concentrations between 100 and 1000 mg/l is deemed toxic to humans. This is an applied analytical research project aimed at examining formaldehyde removal from urban drinking water using a batch electro-photocatalytic (EPC) reactor that uses ultraviolet-A (UV-A) lamp dynode and immobilized ZnO NPs on a zinc sheet-copper electrode. pH, formaldehyde content, lamp intensity, radiation duration, lamp-electrode distance, ZnO NP stacking, and current density are the factors under investigation. They were found to be in the ranges 3-11, 110-330 mg/l, 480-720 mW/cm², 8-32 min, 1.5 cm, 1-3, and 4-12 mA/cm², respectively. The findings demonstrate the relationship between UV-A lamp intensity, radiation duration, and current density with the elimination of formaldehyde. The experimental data better fit a first-order reaction (R² = 0.9982). The most optimal conditions elimination (0 mg/l) of formaldehyde are achieved at pH = 11, radiation period = 8 min, two layers of ZnO NPs, and current density = 8 mA/cm² by the Taguchi model. The results show that increasing pH, radiation period, lamp intensity, and current density all increase removal efficiency. The results show that EPC is a practical and efficient method for treating formaldehyde-contaminated drinking water at high concentrations.