Evaluation of the efficiency of the TiO۲/UV nano-photocatalytic process in the removal of humic and fulvic acids from aqueous solutions

Background: Removing natural organic substances from drinking water sources is necessary to prevent the formation of toxic and carcinogenic disinfection by-products (DBPs). The nano-photocatalytic oxidation process to remove these substances is easier, faster, cheaper, and more efficient than other methods. Methods: This study investigated the efficiency of the TiO۲/UV nano-photocatalytic process in removing humic acid (HA) and fulvic acid (FA) from aqueous solutions. Batch tests were performed to investigate the effect of various parameters such as contact time (۱۵, ۳۰, ۴۵, ۶۰, and ۷۵ minutes), initial pH (۴, ۷, and ۹), initial HA and FA concentration (۰.۵, ۱, ۲, ۵, and ۷ mg/L-۱), TiO۲ dose (۵, ۱۰, ۱۵ and ۲۰ mg/L-۱), and different UV irradiation (۸ W and ۱۶ W) for the removal of HA and FA from aqueous solutions using TiO۲/UV at room temperature (۲۰ ± ۳ °C). The equilibrium adsorption data and the standard parameters were evaluated. Data were analyzed using SPSS version ۲۵. Results: The efficiency of this process in optimal conditions (pH: ۴, anatase TiO۲: ۱۰ mg/L-۱, irradiation time: ۶۰ min, UV = ۱۶ W) for removing humic and fulvic (initial HA concentration: ۲ mg/L-۱ and initial FA concentration: ۵ mg/L-۱) was ۸۹% and ۹۲%, respectively. The analysis of the experimental isotherm data showed that in the adsorption process of HA and FA on TiO۲/UV, the Langmuir isotherm and the first-order reaction had the best fit with the experimental data. Conclusion: TiO۲/UV nano-photocatalytic process is suitable for the photo-degradation and removal of HA and FA in aqueous solutions.

کلیدواژه ها:

Humic substances ، Titanium dioxide ، Photocatalysis ، Water purification ، Water pollutants