Advanced oxidation of high concentrations of formaldehyde in aqueous solution under fluorescent and UV light

Background: Formaldehyde (FA) is a carcinogen compound, which is soluble in water. FA can be removed from aqueous solution using advanced oxidation methods. Methods: In this study, the oxidation of FA was studied under fluorescent and UV light. Hydrogen peroxide (H۲O۲) was used as an oxidant. The pH value and H۲O۲ amount of samples were optimized. The chemical oxygen demand (COD), FA concentration, and H۲O۲ consumption were followed. Results: It was observed that the pH value of the sample was more significant under fluorescent light than UV light at oxidation of FA. The highest COD removal and H۲O۲ reduction were ۱۸.۵۷ and ۳۰.۹۰%, respectively, at pH ۱۲.۰۰, with a ۱:۱ ratio of FA:H۲O۲ under fluorescent light. ۸۶.۴۱% FA and ۶۲.۱۲% COD removal were achieved at pH ۷.۰۰, with a ۱:۲ ratio of FA:H۲O۲, under UV light. It was observed that H۲O۲ was consumed at all pH values under UV light. On the other hand, under fluorescent light, the concentration of H۲O۲ decreased only at pH ۱۲. In control samples containing only H۲O۲, the H۲O۲ reduction was ۹۲.۰۹% at pH ۱۱.۹۱, while it was ۲-۶% at other pH levels under fluorescent light. The H۲O۲ reduction changed between ۳۳ and ۴۴% at different pH values under UV light. The oxidation of FA was found to be suitable for the pseudo-first-order kinetic model and Langmuir isotherm model. Conclusion: The most effective oxidation was obtained at the original pH value (۷.۰۰) and ۱:۲ ratio of FA:H۲O۲ under UV light.

کلیدواژه ها:

Water treatment ، Formaldehyde ، UV light ، Hydrogen peroxide