咖啡渣对铅锌矿山酸性废水中Pb^(2+)和Zn^(2+)的吸附

Adsorpting Pb^(2+) and Zn^(2+) from Acid Mine Drainage by Coffee Grounds

以咖啡渣为原料,结合电子扫描显微镜、红外光谱分析仪和Zeta电位仪等研究吸附条件对吸附效果影响及吸附机理.结果表明:pH值为4、咖啡渣投加量为20g·L-1时,咖啡渣对Pb2+和Zn2+的吸附量最大,分别为5.49,12.38mg·g-1;吸附反应在4h后达到平衡,用拟二级动力学模型和Freundlich方程拟合效果较好;咖啡渣的电负性随pH值增加而增大,吸附Pb2+和Zn2+后表面变平整且出现白色颗粒;红外光谱图结果发现咖啡渣中参与吸附反应的基团主要有酰胺基、酯基、酮基.

Scanning electron microscope, infrared spectrum analyzer and Zeta potentiometer are used to explore the mechanism about the adsorption and the parameters effecton the adsorption rate of Pb2＋ and Zn2＋ by coffee grouds. Test results show that the maximum adsorption quantity appears when pH value is 4 and also 20 g · L-1 adsorbent is added into the aqueous solution. The maximum adsorption quantity of Pb2＋ and Zn2＋ by coffee grouds is 5.49 and 12.38 mg · g-1. The adsorption process reaches equilibrium after 4 hours. And the adsorption process accords with the second order kinetics model and Freundlich equation. The electronegativity of coffee grouds increase while pH value raises and it reduces after adsorpting Pb2＋ and Zn2＋ . White particles appear on the surface of coffee grouds after the adsorption process. FT-IR spectrum indicates that the main functional groups includes amide, ester and keto in the adsorption process.