Oxidation Absorption of Hg⁰ in the Gas Phase Using a Double Catalyzers–Double Oxidants Coactivation Technology

Abstract

An oxidation absorption technology of Hg0 in the gas phase using double metal catalyzers–double oxidants coactivation was developed. Several experiments were performed to study the main influencing factors, key reactive species, oxidation products, and mechanism of Hg0 oxidation absorption. It was found that higher concentration of Fe2+ and Cu2+ led to an increase in Hg0 removal efficiency. The removal efficiency of Hg0 was declined through increasing the reagent pH value, flue gas flow rate, Hg0 inlet concentration, and inlet content of NO/SO2. Changing the removal temperature and concentrations of PMS (peroxymonosulfate) and H2O2 resulted in a dual influence on Hg0 oxidation absorption. Under the optimized experimental conditions, the maximum removal efficiency of Hg0 is up to 97.5%. Due to the significant synergistic activation effect, bigger reactive species yield and higher Hg0 removal efficiency were obtained in the double metal catalyzers–double oxidants coactivation system than those in the other contrasted systems, which were caused by the redox cycling by double metal catalyzers and the free radical capture intermediate formed between double oxidants. The Hg0 oxidation absorption was mainly achieved by the oxidation of •OH and SO4 –•, and Hg2+ was confirmed to be the main products of Hg0 oxidation absorption in the developed coactivation system.

Wet Catalytic Oxidation of a FeMnCe-Activated Semi-Coke Catalyst for Treating Piperazine Wastewater

“…The peaks at 711.50 and 724.00 eV are attributed to the characteristic peaks of the Fe 2p 3/2 and Fe 2p 1/2 spin orbitals, respectively, and the peak at 718.20 eV corresponds to the satellite peak of the Fe 2p 3/2 orbital. The peak area percentage of Fe 3+ accounts for 82.90% after the reaction, which is 21.43% higher than that before the reaction, and the Fe 3+ content increases, indicating that the catalyst still shows high activity after the reaction . The XPS spectra and fitted curves of the 2p orbitals of Mn are shown in Figure e.…”

“…The peak area percentage of Fe 3+ accounts for 82.90% after the reaction, which is 21.43% higher than that before the reaction, and the Fe 3+ content increases, indicating that the catalyst still shows high activity after the reaction. 20 The XPS spectra and fitted curves of the 2p orbitals of Mn are shown in Figure 10e. The spectral peaks at 642.3 and 652.6 eV correspond to the Mn 2p 3/2 and Mn 2p 1/2 orbitals of Mn 4+ in the FeMnCe/ASC catalyst, respectively.…”