2,4-D 对铜在乌栅土胶体和红壤胶体上吸附的影响

应用批平衡法研究了农药2,4-D对Cu在乌栅土胶体和红壤胶体上吸附的影响。结果表明,Cu在两种土壤胶体上的吸附等温线均符合Langmuir方程,Cu在乌栅土胶体上的吸附量较其在红壤胶体上的吸附量要高;在pH3.0～6.7范围内,两种土壤胶体对Cu的吸附量均随溶液pH的升高而升高。2,4-D增加了Cu在土壤胶体上的吸附,2,4-D的浓度越高,Cu的吸附量越大,这主要是由于2,4-D的存在显著增加了平衡液的pH,从而增加了土壤胶体表面所带负电荷量。

Adsorption of Cu on Wushan and red soil colloid as affected by 2,4-D

Adsorptions of Cu on a Wushan soil colloid (WS) and a Red soil colloid (RS) with and without 2,4-D were studied by batch equilibrium experiments. The results indicated that Cu adsorption isotherms fit Langmuir equations well, with high correlation coefficient (R2 = 0.93 ~ 0.98). The WS had higher adsorption capacity for Cu than the RS. Cu adsorption quantities on the two soil colloids increased with the increase of solution pH values within the range from 3.0 to 6.7. The presence of 2,4-D increased Cu adsorption quantity on both of the soil colloids. The higher the solution 2,4-D concentration, the more Cu adsorbed on the soil colloids. It can be attributed to pH-increase induced by 2,4-D which resulted in the increase of the negative surface charges of soil colloids.