Degradation of formaldehyde from wastewater by batch re-circulation process using a photocatalytic reactor

The most abundant component in industrial effluent is the carcinogenic formaldehyde. The presence of formaldehyde in industrial waste water is increasing day by day. It can be removed by various processes viz., photocatalytic reaction, electrochemical methods, and biological methods. This study involves the degradation of formaldehyde by photo catalytic method. In the biological method, the maximum percentage reduction of formaldehyde was achieved at low initial formaldehyde concentration range of 100-300 mg/L. For higher concentration more than 300 mg/L, the most efficient method is the photo catalytic degradation. The experiments were conducted in a UV photo catalytic reactor and it was a batch reactor with recirculation process. It was carried out at various initial formaldehyde concentrations such as 500; 1,000; and 1,500 mg/L and the feed flow rate was adjusted 4, 8, and 12 LPH. The flow rate of the feed was controlled by using peristaltic pump. The pH of the feed solution maintained was 7 and the catalyst dosage was fixed to 0.3 g/L. The sample was collected at each 1 h interval and analyzed by UV-Visible spectrophotometer at 410 nm by using Hantzsch reagent method. For initial concentration of 1,000 mg/L at 8 LPH, the maximum efficiency of 76% was obtained when compared to other concentration. From the study, it was predicted that photo catalytic method is most feasible for higher concentrations.