砂壤中铜的吸附行为及其影响因素研究

研究了果园附近砂壤中Cu的吸附行为，并探讨了pH值及土壤有机质对吸附的影响。结果表明，供试土壤对Cu的吸附行为可用Freundlieh方程拟合，电性吸附态Cu较易解吸；而专性吸附态Cu较难解吸。动力学实验表明，最初4h内的吸附量占总吸附量的60％以上，8h后达到平衡；而解吸在最初30min内占了近80％，2h后可达平衡。低pH值时，H^＋和Cu发生竞争吸附，可明显抑制土壤对Cu的吸附；随pH值的升高，抑制作用减弱，其logKd与pH呈线性正相关；在中性和偏碱性范围，pH值对土壤吸附Cu的影响不大。原土去除有机质后对Cu的分配系数降低了10倍。

ADSORPTION BEHAVIOR OF Cu IN SANDY LOAM AND ITS AFFECTING FACTORS

Effects of pH and organic matter on Cu adsorption in a sandy loam near orchard were studied.Results showed that i)the isotherm of Cu adsorption could be described by Freundlich equation and ii)statically adsorbed Cu was easier to get desorbed than specifically adsorbed one.Kinetic experiments demonstrated that up to 60% of the Cu adsorption occurred within the initial 4 h,and equilibrium was reached after 8 h,while up to 80% of the Cu desorption did within the initial 30 min, and equilibrium was reached after 2 h.Cu adsorption rate was lower at low pH than at higher pH,which was a result of competitive adsorption of H⁺,and logK_d showed a positive linear correlation with pH while in neutral and alkali condition,the effect of pH on adsorption could be neglected.The removal of organic matter from the soil reduced the distribution coefficient K_d 10 times as compared to the natural soil.