磷酸作用下土壤砷的变化特征研究

Study on the Variation Characteristics of Soil Arsenic under the Action of Phosphoric Acid

为了探明磷酸洗脱剂作用下土壤砷的变化特征,在不同的萃取剂浓度、液土比条件、萃取时间下,对萃取后土壤总砷和各形态砷含量变化进行研究。结果表明:对于砷含量为98.53 mg·kg^-1的土壤,随着磷酸浓度的升高,对土壤砷的萃取率呈先增加后基本不变的趋势,磷酸萃取土壤砷的最佳浓度为1.5 mol·L^-1;土液比对磷酸萃取土壤砷的影响较小;随着萃取时间的增加,磷酸对土壤砷的萃取量变化较小,变幅在9.3%以内,萃取效率最高的时间为1 h;在浓度为1.5 mol·L^-1、土液比为1∶3、萃取时间为1 h的条件下,磷酸对土壤中各形态砷的去除量特征为:铝结合态>铁结合态>交换态>水溶态>钙结合态>残渣态。

In order to ascertain the variation characteristics of soil arsenic under the action of phosphoric acid eluent,the changes of total arsenic and various forms of arsenic in the soil after extraction were studied under different ex⁃tractant concentrations,soil-liquid ratio conditions and extraction time.The results showed that for the soil with 98.53 mg·kg^-1 arsenic content,with the increase of phosphoric acid concentration,the extraction rate of arsenic in⁃creased first and then remained unchanged.The best concentration of arsenic extracted by phosphoric acid was 1.5 With the increase of extraction time,the amount of extraction of arsenic from soil by phosphoric acid changed little,the range was within 9.3%.Under the conditions of 1.5 mol·L^-1 concentration,1∶3 ratio of soil to liquid and 1 h ex⁃traction time,the removal of various forms of arsenic in soil by phosphoric acid was:aluminum-bound state>ironbound state>exchange state>water-soluble state>calcium-bound state>residue state.