Evaluating the efficiency of formaldehyde degradation from aqueous environment by sonozone technique

Formaldehyde contamination in urban drinking water posed significant health and environmental risks, necessitating effective and sustainable elimination strategies. This applied research investigated the efficacy of the Sonozone process-a hybrid advanced oxidation technique combining ultrasound and ozone-for formaldehyde degradation in water. Laboratory-scale experiments were conducted under varying conditions of pH (3-11), contact time (0-32 min), formaldehyde concentration (110-330 mg/L), ozone dosage (0.2-0.6 mg/min L), and electrical power (50-150 W). Formaldehyde concentrations were measured using spectrophotometry at 400 nm via the chromotropic acid 6252 colorimetric method. The process followed first-order kinetics (R2 = 0.9839), and statistical analysis via one-way ANOVA (p < 0.05) confirmed the significance of operational parameters. Optimal elimination (100% efficiency) was achieved at 110 mg/L formaldehyde, pH 3, 32 min contact time, 0.6 mg/min·L ozone, and 150 W power. The Taguchi model identified formaldehyde concentration as the most influential factor. Energy consumption was calculated at 371 kJ total and 30,601 kJ/kg removed. The enhanced oxidation was attributed to ultrasound-induced cavitation, which promotes ozone decomposition and hydroxyl radical generation. Compared to other AOPs, Sonozone offered superior environmental compatibility and operational simplicity. Based on these findings, Sonozone was recommended as an effective and sustainable method for formaldehyde elimination in urban water treatment applications.