Efficiency Rate of Photocatalytic UV/ZnO in Removing Humic Acid from Aqueous Solution

Humic substances belong to a group of micro molecular of organic substance with different molecular weight produced by reaction of biological and geochemical process. They are known as one of the main prefabrications of disinfection byproducts. This study aimed at investigating the efficacy of (ZnO) nanoparticle under UV/ZnO radiation in removing humic acid. This study was conducted under laboratory condition. An interval reactor was used to eliminate humic acid by (ZnO) nanoparticle and UV lamp (125 W Philips HPLN). The humic acid was considered in 2, 5, 7 and 10 mg/lit concentrations. To measure the residue of humic acid after radiation of photo Photocatalytic, Spectrophotometer model (UV/VIS Lambda 25 Perkin Elmer, Shelton) was used. The results showed a decrease in efficiency rate when humic acid concentration and pH increased. By increasing the time of photocatalytic activity the removal effect increased. Also, we observed that single-step process and two-step process with higher removal efficiency at Zno concentration of 0.2 mg/l and 0.5 mg/l, respectively. The two-step process was found more capable of removing humic acid with 98.95% efficiency at the concentration of 0.5 mg/l ZnO, detention time of 30min, and at pH 4. This study suggests the use of UV/ZnO process as a suitable method in removing humic acid from aqueous solutions.