UV-Activated and Fe2+-Catalyzed H2O2 for the Treatment of Dye-Contaminated Water: Kinetics, Mechanism and Toxicity Investigations
Wisal Ahmad, Roman Shah, Hameed Ul Haq, Dilaram Khan, Shahab Khan, Abdulaziz Al‐Anazi, Javed Ali Khan, Nusrat Rezwana Binte Razzak, Changseok Han
Abstract
This study investigated the removal of methylene blue (MB) by different UV, UV-catalyzed H2O2 (UV/H2O2) and UV-and-iron-catalyzed H2O2 (UV/H2O2/Fe2+)-based advanced oxidation processes. At pH 6.0, the removal of MB (15 mg/L) was found to be 6.31% at 60 min for UV only. However, the combination of H2O2 (5 mM) with UV greatly enhanced the removal efficiency as 96.44% degradation of MB was found in the UV/H2O2 process at 60 min. Furthermore, the UV/H2O2/Fe2+ process was observed to be even more efficient than UV/H2O2, achieving 99.11% MB degradation at 30 min of treatment under the experimental conditions of [MB]0 = 15 mg/L, [H2O2]0 = 2 mM, [Fe2+]0 = 0.5 mg/L, and pH0 = 3.0. Furthermore, the removal of TOC was found to be 59 and 71% for UV/H2O2 and UV/H2O2/Fe2+, respectively. The pH did not change the efficiency of the UV/H2O2 process significantly; however, it greatly affected the efficiency of the UV/H2O2/Fe2+ system. The results demonstrate that both UV/H2O2 and UV/H2O2/Fe2+ could be used for the effective degradation and mineralization of MB.