土壤对硅的吸附与解吸特性研究

Study on Adsorption and Desorption of Silicon in Soils

对几种代表性土壤进行了硅的吸附———解吸试验，并用三种等温吸附方程对实验结果进行了拟合。结果表明：实测值与Ｌａｎｇｍｕｉｒ，Ｆｒｅｕｎｄｌｉｃｈ和Ｔｅｍｋｉｎ方程都有较好的相关性，相关系数０．９１９８～０．９９９４，达到显著或极显著水平，其中以简单Ｌａｎｇｍｕｉｒ等温式与本实验资料最为吻合。根据Ｌａｎｇｍｕｉｒ方程计算的最大吸硅量ｘｍ和最大缓冲容量ＭＢＣ与土壤物理性粘粒和活性氧化铁、铝含量有关，能较好反映土壤供硅特性。几种供试土壤ＭＢＣ大小排序为：湖泥田＞马肝泥田＞砖红壤＞青泥田＞粉砂泥田＞壤质潮土。土壤吸附硅的解吸受土壤粘粒和氧化铁、铝含量影响，也与土壤吸附位硅饱和度有关，供试土壤吸附硅解吸率在２６．６％～５２．７％之间。

The adsorption and desorption of silicon on six kinds of soils from different parent materials were studied.The results (1) The isothermal silicon sorption data obtained all fitted with Langmuir,Freundlich and Temkin equation ,and the conventional Langmuir equation seemed to be the best one to describe the sorption data as judged by its very significant correlaton coefficients.(2) The parameters in the single Langmuir equation,namely the adsorption maximum(x m) and Maximum Buffering Capacity(MBC),were good parameter to assess silicon sorption.x m and MBC were closely related to content of Soil clay(<0.01mm) and Fe 2O 3、Al 2O 3.(3) The silicon adsorbed by examined soils could not be completely desorbed by water,and its ratio varied with soil clay and concentration of added Si.The rate of Silicon desorbed in soils was about 26.2%～52.7%.