掺杂水铁矿对黄河表层沉积物吸附Cd的影响

The Effect of Ferrihydrite Doping on Adsorption of Cd onto Sediments from Yellow River

以人工合成的水铁矿作为掺杂吸附剂,分析了掺杂水铁矿前后黄河乌拉特前旗段表层沉积物对重金属Cd的吸附特性,探讨了吸附时间、pH、温度和Cd初始浓度对沉积物吸附Cd的影响.结果表明:沉积物对Cd的热力学吸附过程可以用Langmuir吸附等温式描述;掺杂水铁矿3%、pH=6.5、25℃、振荡120min为最佳吸附条件.在此条件下,沉积物对Cd的吸附量达到2.15mg/g;温度对吸附效果有影响,18℃下沉积物对Cd的吸附量总体高于25℃和30℃下的吸附量,说明该吸附反应是放热反应;掺杂水铁矿比例越高,沉积物对Cd的吸附能力越强.

The adsorption characteristics of Cd onto sediments doped with ferrihydrite from Wulateqianqi of Yellow River were investigated. The effects of adsorption time, pH,temperature and concentration of Cd onto sediments were discussed. The results illustrated that the adsorption processes of sediments with doping ferrihydrite to Cd were consistent with Langmuir adsorption isotherm curves; under the reaction condition of pH=6.5,25℃ and reaction time of 120 min,the adsorption capacity of Cd onto sediments with 3% doping ferrihydrite was 2.15 mg/g; the adsorption capacity under 18℃ was higher than that of at 25℃ and 30 ℃ ,indicating the adsorption is exothermic reaction; the adsorption capacity of Cd onto sediments increased with the increase in proportion of ferrihydrite doping.