Oxalic acid and UV enhanced arsenic leaching from coal in flue gas desulfurization by coal slurry

被引：0
|
作者：
Li J. [1 ]
Qiu S. [1 ]
Sun W. [1 ]
机构：
[1] College of Environmental Science and Engineering, Qingdao University, Shandong, Qingdao
来源：
Huagong Xuebao/CIESC Journal | 2023年 / 74卷 / 08期
关键词：
arsenic; free radicals; kinetic model; oxalic acid; oxidation; sulfur dioxide; ultraviolet light;
D O I：
10.11949/0438-1157.20230513
中图分类号：
学科分类号：
摘要：
Currently, coal is still the main energy source in our country. During coal combustion, arsenic will be discharged into the atmosphere with flue gas. Arsenic is highly toxic and harmful to the environment and human health. Therefore, it is of great practical significance to study the arsenic removal technology from coal. Using N2, O2 and SO2 to simulate flue gas, the effects of main factors on arsenic leaching from coal, As(Ⅲ) oxidation and SO2 removal were studied in a 1 L photoreactor. The process mechanism was analyzed, and the rate control step of the leaching process was determined. The results showed that both ultraviolet(UV) irradiation and oxalic acid could effectively increase the extraction ratio of arsenic. At 180 min, under pH 2.5 and dark conditions, adding 1.0 mmol/ L oxalic acid could increase the arsenic extraction ratio by 32.9%. Under UV irradiation, the arsenic extraction ratio could be further increased by 21.3%, and the ratio of As(Ⅲ) in the leaching solution to the total arsenic was less than 13%, and the SO2 removal efficiency could also be improved. Low pH was beneficial for arsenic leaching from coal, but unfavorable for SO2 removal. Both arsenic extraction ratio and SO2 removal efficiency increased significantly with the increase of temperature. The apparent activation energy for process of arsenic leaching from coal was calculated to be 4.9 kJ/mol, indicating that the arsenic leaching process was controlled by the diffusion process in the reacted solid layer. The free radical quenching experiments showed that sulfate radical and hydroxyl radical were the main free radicals in the oxalic acid-enhanced coal arsenic leaching system under UV irradiation. ATR-FTIR and XPS characterization results further confirmed the measured results of the leaching solution. © 2023 Materials China. All rights reserved.
引用
收藏
页码：3522 / 3532
页数：10
相关论文
共 45 条
  • [1] Wang C B, Liu H M, Zhang Y, Et al., Review of arsenic behavior during coal combustion: volatilization, transformation, emission and removal technologies, Progress in Energy and Combustion Science, 68, pp. 1-28, (2018)
  • [2] Liu H M, Wang C B, Sun X, Et al., Volatilization of arsenic in coal during isothermal oxy-fuel combustion, Energy & Fuels, 30, 4, pp. 3479-3487, (2016)
  • [3] Lopez-Anton M A, Diaz-Somoano M, Fierro J L G, Et al., Retention of arsenic and selenium compounds present in coal combustion and gasification flue gases using activated carbons, Fuel Processing Technology, 88, 8, pp. 799-805, (2007)
  • [4] Zhang Y, Wang C B, Li W H, Et al., Removal of gas-phase As<sub>2</sub>O<sub>3</sub> by metal oxide adsorbents: effects of experimental conditions and evaluation of adsorption mechanism, Energy & Fuels, 29, 10, pp. 6578-6585, (2015)
  • [5] Kang Y, Liu G J, Chou C L, Et al., Arsenic in Chinese coals: distribution, modes of occurrence, and environmental effects, Science of the Total Environment, 412, 413, pp. 1-13, (2011)
  • [6] Sundaram H P, Cho E H, Miller A., SO<sub>2</sub> removal by leaching coal pyrite, Energy & Fuels, 15, 2, pp. 470-476, (2001)
  • [7] Black A, Craw D., Arsenic, copper and zinc occurrence at the Wangaloa coal mine, southeast Otago, New Zealand, International Journal of Coal Geology, 45, 2, pp. 181-193, (2001)
  • [8] Sun W S, Liu J C, Wang L C, Et al., Aluminum-enhanced coal pyrite leaching during SO<sub>2</sub> removal with coal slurry, Water, Air, & Soil Pollution, 227, 7, (2016)
  • [9] Moses C O, Kirk Nordstrom D, Herman J S, Et al., Aqueous pyrite oxidation by dissolved oxygen and by ferric iron, Geochimica et Cosmochimica Acta, 51, 6, pp. 1561-1571, (1987)
  • [10] Lu Z Z, Sun W S, Guo Y F, Et al., Effects of O<sub>2</sub> mole fraction and ultraviolet irradiation on arsenic leaching from coal with flue gas, Journal of Chemical Engineering of Chinese Universities, 33, 4, pp. 989-997, (2019)
12345