咖啡渣对铅锌矿山酸性废水中Pb2+和Zn2+的吸附

Adsorpting Pb2+ and Zn2+ from Acid Mine Drainage by Coffee Grounds

摘要:

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20 g·L-1时，咖啡渣对Pb2+和Zn2+的吸附量最大，分别为5.49，12.38 mg·g-1；吸附反应在4 h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.

Abstract:

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.