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应用模拟试验方法,研究了外源As(Ⅲ)在第四纪红土、紫色砂页岩和花岗岩3种母质发育土壤中的老化过程,并分析了该过程中砷的有效性、结合态等的变化.结果表明:经过120 d老化后,3种土壤中均只能检测到As(Ⅴ)的存在;伴随老化过程的进行,土壤中有效态砷的含量均呈下降趋势,且下降幅度为:紫色砂页岩发育土壤(RS2)>花岗岩发育土壤(RS3)>第四纪红土发育土壤(RS1).应用准二级动力学方程可以较好地模拟3种土壤中有效态砷含量的变化(P<0.05),土壤p H、有机质及铁铝锰氧化物是影响砷老化的主要因素,且锰氧化物的影响大于铁铝氧化物(P<0.05).相关分析表明,非专性吸附态砷和专性吸附态砷是构成土壤有效砷的主要形态.
The aging process of exogenous As (Ⅲ) in soils developed from Quaternary laterite, purple sandstone and granite was studied by means of simulation test. The effects of As The results showed that As (Ⅴ) could only be detected in all three soils after 120 days of aging. With the progress of aging, the content of available arsenic in soil decreased, and the decreasing range was: Purple sand shale developed soil (RS2)> granite developed soil (RS3)> Quaternary red clay developed soil (RS1). The application of pseudo second-order kinetic equation can well simulate the change of available arsenic in three soils P <0.05). Soil p H, organic matter and ferro-alumino-manganese oxide were the main factors affecting the aging of arsenic, and the influence of manganese oxide was greater than that of ferro-aluminum oxide (P <0.05) .The correlation analysis showed that the non-specific adsorption state Arsenic and specifically adsorbed arsenic are the main forms of soil available arsenic.