Calcium Sulfite Solids Activated by Iron for Enhancing As(III) Oxidation in Water

Desulfurized gypsum (DG) as a soil modifier imparts it with bulk solid sulfite. The Fe(III)–sulfite process in the liquid phase has shown great potential for the rapid removal of As(III), but the performance and mechanism of this process using DG as a sulfite source in aqueous solution remains unclear. In this work, employing solid CaSO3 as a source of SO32−, we have studied the effects of different conditions (e.g., pH, Fe dosage, sulfite dosage) on As(III) oxidation in the Fe(III)–CaSO3 system. The results show that 72.1% of As(III) was removed from solution by centrifugal treatment for 60 min at near-neutral pH. Quenching experiments have indicated that oxidation efficiencies of As(III) are due at 67.5% to HO•, 17.5% to SO5•− and 15% to SO4•−. This finding may have promising implications in developing a new cost-effective technology for the treatment of arsenic-containing water using DG.

Study of oxidation of calcium sulfite in flue gas desulfurization by pore-type surface dielectric barrier discharge

Novelty: a new pore-type surface dielectric barrier discharge (PSDBD) reactor was first applied in the oxidation of calcium sulfite in flue gas desulfurization.

The Study on Thermal Stability of Hg and S Element in Semi-Dry Flue Gas Desulfurization Ash

The semi-dry flue gas desulfurization technology is widely used by coal-fired power plant. Desulfurization ash produced by semi-dry flue gas desulfurization, which consist CaSO3, CaCO3, Ca (OH) 2, CaSO4 and so on. It will bring new environment pollution if not been disposed properly. Building material industry is the main field in terms of the comprehensive utilization of desulfurization ash. While hazardous elements especial S and Hg may be released in the condition of temperature changes in the process of desulfurization ash utilization, causing second environment pollution. Combined with the research achievement of preparing autoclaved brick before, the content of S and Hg in raw materials and autoclaved brick were studied during the thermal utilization process in this article. The thermal stability of calcium sulfite was analyzed by the chemical reagent calcium sulfite. The results shown that calcium sulfite only lost crystal water whether in oxygen or air when the temperature is below 450°C, calcium sulfite was completely oxidized to calcium sulfate when the temperature is 475 °C in oxygen or 515°C in air. The contents of S and Hg which existed in desulfurization ash were 7.03%wt and 460μg/kg, respectively. The contents of S and Hg in autoclaved brick which made by desulfurization ash mainly were 5.16%wt and 450μg/kg, respectively. The results shown that the content of elements S and Hg in raw materials and autoclaved brick were roughly the same, which indicated that S and Hg no escape in the process of preparing autoclaved brick. The research provided a certain references for the comprehensive utilization of semi-dry flue gas desulfurization ash in the condition of heat and humid.