Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China.
Bull Environ Contam Toxicol. 2021 Jan;106(1):126-133. doi: 10.1007/s00128-020-02925-7. Epub 2020 Jul 6.
Adsorption of arsenate, a common soil contaminant, on natural occurring iron oxides controls arsenate adsorption on soils, especially on iron rich soils. However, soils contain multiple iron minerals and their contributions for arsenate adsorption on the bulk soil are unclear. In this study, Wenzel's sequential extraction procedure (SEP) was used to characterize different fractions of iron oxides in the paddy soils from Guangxi, China. Soils treated with different extractants in the SEP (i.e. soils contained different iron fractions) were used to study arsenate adsorption on different iron fractions in the soil. Langmuir model was used to assess arsenate adsorption capacities of those iron fractions. The results showed that though amorphous iron made up only 16% of the total iron in the soil, it accounted for 82% of the soil adsorption capacity. Besides, arsenate adsorption capacity on the soils could be estimated by linear addition of arsenate adsorption capacity on the amorphous iron oxides fraction and that on the other iron oxides fraction. This study implied a possibility to use iron fractions characterized by Wenzel's SEP to evaluate arsenate adsorption on the bulk soils.
砷酸盐是一种常见的土壤污染物，其在天然存在的氧化铁上的吸附控制着砷酸盐在土壤上的吸附，特别是在富铁土壤上。然而，土壤中含有多种铁矿物，它们对土壤中砷酸盐吸附的贡献尚不清楚。本研究采用温泽尔连续提取程序（SEP）来表征来自中国广西的稻田土壤中不同形态的氧化铁。用 SEP 中的不同提取剂（即土壤中含有不同的铁形态）处理土壤，用于研究砷酸盐在土壤中不同铁形态上的吸附。采用 Langmuir 模型评估了这些铁形态的砷酸盐吸附容量。结果表明，尽管无定形铁仅占土壤总铁的 16%，但它却占土壤吸附容量的 82%。此外，土壤对砷酸盐的吸附容量可以通过无定形氧化铁分和其他氧化铁分的砷酸盐吸附容量的线性加和来估算。本研究表明，用温泽尔 SEP 表征的铁形态来评估土壤对砷酸盐的吸附是有可能的。
