土壤中价态砷的浸取方法研究

RESARCH ON SOAK METHOD OF VALENCE FORM OF ARSENIC IN SOIL

土壤砷的价态分析一直是个比较困难的问题，其主要原因是尚未找到行之有效的、不改变砷价态的土壤样品预处理方法。本文针对土壤砷主要以Ｆｅ、Ａｌ、Ｃａ、Ｍｇ盐的沉积物形态吸附于土壤中，选取柠檬酸铵－ＨＣｌ（ｐＨ＝５）的混合体系作浸取剂，利用络合和离子交换原理转换出沉积物中的金属阳离子，从而释放出Ａｓ（Ⅴ）．用超声波作震荡、萃取温度４０℃、时间５ｈ，即可达到９０％以上的萃取率。在此条件下，经各价态砷的回收试验，浸取方法的精密度试验，均取得了满意的结果。无论是浸取率、浸取时间，还是价态影响上都大大优于已有的类似研究工作。

Valence form analysis of soil As is a Knottoy problem all along.The main reason is effective pretreatment of soil sample that do not change As valence form is not found. Since soil As is absprbed in the siol under thesediment state of Iron,Aluminum,Copper and Magnesium salt,we choose the mixture of ammonium citrate-HCl(ph=5) as infusion and make use of exchanging principle of complex and ion to converce the mental cation in sediment,thus release As.We will get over 90 percent of extraction rate after 5 hours by use of ultrasonic waves shake,40℃ extraction temperature.Under such conditions,we get satisfying conclusion after receivetext of all sorts of valence form As,precision text of soak methods.No matter soak rate.Soak time or effection of valence form are more excellent than that of other similar research work.