牡蛎壳粉对水体中低浓度重金属离子的吸附性能研究

The study on adsorptive capability of oyster shell powder on low concentration of heavy metal ions in water

为研究牡蛎壳粉对水体中常见重金属离子的吸附性能,实验中分别探讨了牡蛎壳粉在不同添加量、重金属离子浓度、吸附温度、酸碱环境、吸附时间下对水体中Cu2+、Zn2+、Pb2+、Cd2+、Cr(Ⅵ)的吸附情况;并进行牡蛎壳粉吸附动力学、热力学实验研究和SEM图谱分析。结果显示,牡蛎壳粉的最适宜吸附条件为常温下,添加量1 g/L,溶液初始pH值为5.5,吸附时间为24 h,此时其对水体中浓度分别为1mg/L的Cu2+、Zn2+、Pb2+、Cd2+、Cr(Ⅵ)等5种重金属离子的去除率分别为84.96%、76.77%、78.57%、51.99%和41.39%,且随着溶液初始浓度的上升,牡蛎壳粉对5种重金属离子的吸附量呈上升趋势,饱和吸附量分别为9.43、9.65、9.03、4.67、1.83 mg/g;牡蛎壳粉对5种重金属离子的吸附符合准二级动力学方程和Langmuir等温模型;SEM图谱表明吸附Cu2+、Zn2+、Pb2+的牡蛎壳粉表面均有二次固体生成,吸附Cd2+、Cr(Ⅵ)的牡蛎壳粉表面无明显现象。

In order to study the adsorptive capability of oyster shell powder on low concentration heavy metal ions in water, five kinds of heavy metal ions Cu^（2＋） , Zn^（2＋） , Pb^（2＋） , Cd^（2＋） , Cr（ VI ） had been added in the water, the influence of different adding amount, adsorption temperature, pH value, adsorption time and initial concentration of solution had been discussed. And it also carried out dynamics research, thermodynamic study and SEM analysis. Results showed that Cu^（2＋） ,Zn^（2＋） ,Pb^（2＋） had good removal capacity, but Cd^（2＋） ,Cr（VI） was relatively weak. The adsorption by oyster shell powder was in line with the pseudo - second - order model and the Langmuir isotherm model. The SEM maps indicated that secondary solid was built on the oyster shell powder surface after adsorbing Cu^（2＋） , Zn^（2＋） , Pb^（2＋） and no obvious phenomena on the surface after adsorbing Cd^（2＋） , Cr （VI）.