Photooxidative removal of Hg° from simulated flue gas using UV/H_2O_2 advanced oxidation process: Influence of operational parameters

摘要

Element mercury (Hg~0) from flue gas is difficult to remove because of its low solubility in water and high volatility. A new technology for photooxidative removal of Hg° with an ultraviolet (UV)/H_2O_2 advanced oxidation process is studied in an efficient laboratory-scale bubble column reactor. Influence of several key operational parameters on Hg° removal efficiency is investigated. The results show that an increase in the UV light power, H_2O_2 initial concentration or H_2O_2 solution volume will enhance Hg~0 removal. The Hg~0 removal is inhibited by an increase of the Hg~0 initial concentration. The solution initial pH and pH conditioning agent have a remarkable synergistic effect. The highest Hg~0 removal efficiencies are achieved at the UV light power of 36 W, H_2O_2 initial concentration of 0.125 mol/L, Hg~0 initial concentration of 25.3 μg/Nm~3 solution initial pH of 5, H_2O_2 solution volume of 600 ml, respectively. In addition, the O_2 percentage has little effect on the Hg~0 removal efficiency. This study is beneficial for the potential practical application of Hg~0 removal from coal-fired flue gas with UV/H_2O_2 advanced oxidation process.