DEGRADATION OF M-CRESOL WITH Mn DOPED ZnO NANOPARTICLES UNDER VISIBLE LIGHT IRRADIATION

摘要

The effective removal of m-cresol is currently both an environmental problem and economic challenge. ZnO removed several organic contaminants under UV irradiation; however, UV equipment can be very expensive to operate on a large scale. Therefore, using a sunlight photocatalyst offers a way to overcome both problems. This paper shows how degradation of m-cresol was carried out, in the presence of visible light (46% sunlight); by a 1.0 wt% Mn doped ZnO as photocatalyst. To measure the efficiency of photodegradation, different variables including amount of photocatalyst, concentration of m-cresol and pH were studied. The residue of m-cresol and mineralization were measured using UV-VIS spectrophotometer and TOC analyzer, respectively. The intermediate was detected by Ultra Performance liquid Chromatography (UPLC). The results showed that m-cresol has high stability in the presence of visible light but absence of photocatalyst, and adsorption of m-cresol over photocatalyst was 5%. In optimum conditions, the amount of photocatalyst and concentration of m-cresol were 1.5 g/L and 35 ppm, respectively. M-cresol photodegradation was favorable in the pH range of 6-9. TOC studies showed that 68% of total organic carbon was excited from solution during irradiation time. The detected intermediates were 2,5-hydroxy-benzalde-hyde and 3,5-hydroxytoluene. Reusability showed no significant reduction in photocatalytic performance/m-cresol photodegradation. This study indicates that 1.0 Mn-doped ZnO can remove m-cresol from wastewater under visible light irradiation, being more economic than UV light, and this methodology could be applied on an industrial scale.