Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065, China.
National Engineering Research Center of Clean Technology in Leather Industry, Sichuan University, Chengdu 610065, China.
J Hazard Mater. 2021 Mar 5;405:124699. doi: 10.1016/j.jhazmat.2020.124699. Epub 2020 Nov 28.
The kinetics and mechanisms of the oxidation of Cr(III) in soil contaminated by unsaturated oils were investigated. Batch experiments were performed with unsaturated oils, namely, fish oil, hydrogenated lard oil, rapeseed oil, and caster oil. Impacts of environmental parameters, including temperature, soil pH, UV irradiation, oil content, and soil moisture content were examined. Results showed that oxidation of Cr(III) in oil-treated soils was accompanied by the formation of Cr(VI), which first increased and then decreased. Changes in the peroxide values of oils and the production of hexanal in the soil indicated that hydroperoxide was closely related to the formation of Cr(VI). tert-Butylhydroperoxide, as a model molecule of hydroperoxide, significantly enhanced the oxidation of Cr(III) in water. This result further showed that hydroperoxides were responsible for the oxidation of Cr(III). Native soil substances, such as organic matter, Fe(II), and microbes, and the decomposition products of hydroperoxides, such as aldehydes, could reduce Cr(VI). The change in Cr(VI) content in the soil resulted from the competition between the oxidation of Cr(III) and the reduction of Cr(VI). High temperature, high soil pH, UV irradiation, and low soil moisture content could facilitate the oxidation of Cr(III), which is of environmental significance.
研究了不饱和油污染土壤中 Cr(III)的氧化动力学和机制。进行了批实验，使用不饱和油，即鱼油、氢化猪油、菜籽油和蓖麻油。研究了环境参数，包括温度、土壤 pH 值、紫外线辐射、油含量和土壤含水量对氧化的影响。结果表明，油处理土壤中 Cr(III)的氧化伴随着 Cr(VI)的形成，Cr(VI)先增加后减少。油的过氧化物值的变化和土壤中己醛的生成表明过氧化物氢与 Cr(VI)的形成密切相关。叔丁基过氧化物作为过氧化物的模型分子，显著促进了水中 Cr(III)的氧化。这一结果进一步表明过氧化物是 Cr(III)氧化的原因。天然土壤物质，如有机物、Fe(II)和微生物，以及过氧化物的分解产物，如醛类，可以还原 Cr(VI)。土壤中 Cr(VI)含量的变化是 Cr(III)氧化和 Cr(VI)还原竞争的结果。高温、高土壤 pH 值、紫外线辐射和低土壤含水量可以促进 Cr(III)的氧化，这具有环境意义。
