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

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 - g/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