Photooxidative removal of Hg0 from simulated flue gas using UV/H2O2 advanced oxidation process: Influence of operational parameters

Abstract

Element mercury (Hg0) from flue gas is difficult to remove because of its low solubility in water and high volatility. A new technology for photooxidative removal of Hg0 with an ultraviolet (UV)/H2O2 advanced oxidation process is studied in an efficient laboratory-scale bubble column reactor. Influence of several key operational parameters on Hg0 removal efficiency is investigated. The results show that an increase in the UV light power, H2O2 initial concentration or H2O2 solution volume will enhance Hg0 removal. The Hg0 removal is inhibited by an increase of the Hg0 initial concentration. The solution initial pH and pH conditioning agent have a remarkable synergistic effect. The highest Hg0 removal efficiencies are achieved at the UV light power of 36W, H2O2 initial concentration of 0.125 mol/L, Hg0 initial concentration of 25.3 μg/Nm3, solution initial pH of 5, H2O2 solution volume of 600 ml, respectively. In addition, the O2 percentage has little effect on the Hg0 removal efficiency. This study is beneficial for the potential practical application of Hg0 removal from coal-fired flue gas with UV/H2O2 advanced oxidation process.