蚓粪腐殖酸对Cd2+的吸附作用研究

Study on the adsorption of Cd2+ by vermi-compost humic acid

以蚯蚓粪中提取到的腐殖酸为研究材料,采用傅里叶变换红外光谱仪分析了蚓粪腐殖酸的功能基团组成,考察了pH、Cd^2+初始浓度和吸附时间对蚓粪腐殖酸吸附Cd^2+的影响,得到蚓粪腐殖酸对Cd^2+的最佳吸附条件。研究结果表明:蚓粪腐殖酸的红外光谱特征吸收峰主要位于3300~3600 cm-1,主要功能基团为羧基、羟基和胺基;pH小于4.0时,蚓粪腐殖酸对Cd^2+的吸附效果较差,近中性条件下吸附效果最佳;Cd^2+初始浓度对吸附效果影响较大,Langmuir模型模拟得到Cd^2+的最大饱和吸附量为4.47 mg/g;蚓粪腐殖酸对Cd^2+的吸附作用较为稳定,吸附40 min后基本达到饱和;蚓粪腐殖酸对Cd^2+有较强的吸附能力,为土壤Cd^2+污染修复提供参考。

The humic acid extracted from vermi-compost was selected as study materials,the composition of functional group in vermi-compost humic acid was analyzed by Fourier transform infrared spectroscopy.The effect of pH,initial Cd^2+concentration and adsorption time on the adsorption process was investigated,then optimal adsorption conditions were obtained.The results showed that the characteristic infrared peak of vermi-compost humic acid was mainly located at 3300-3600 cm-1,and the main functional groups were carboxyl,hydroxyl and amine groups.When pH was less than 4.0,the vermi-compost humic acid had a poor adsorption effect on Cd^2+,and the adsorption effect was the best under nearly neutral conditions;initial Cd^2+concentration had a great effect on the adsorption,and the maximum saturated adsorption capacity was 4.47 mg/g simulated by Langmuir model;the adsorption of Cd^2+by vermi-compost humic acid was stable,and the adsorption reached saturation after 40 min;the vermi-compost humic acid had a strong adsorption capacity for Cd^2+,which could be used for repair of Cd^2+pollution soil.