【摘要】 为探索咖啡渣的资源化利用途径，通过L-半胱氨酸接枝改性咖啡渣制备出一种新型吸附剂，用于去除水溶液中的重金属铅（Pb）。研究发现，L-半胱氨酸修饰的咖啡渣对铅具有较好的吸附性能，吸附剂投加量2 g/L,pH为4,吸附时间为1 h,平衡吸附时的吸附量为47.53 mg/g, Pb²⁺的去除率达到95.06%。研究表明，准二级动力学模型对L-半胱氨酸改性咖啡渣吸附Pb²⁺的描述更加吻合，表明其吸附过程以化学吸附为主导机制。通过热力学分析发现，该吸附过程为自发的吸热反应。等温吸附实验数据与Freundlich模型具有良好拟合度，证实吸附发生在非均质表面，且以多分子层吸附形式进行。通过全自动比表面及孔隙度分析仪（BET）、扫描电子显微镜（SEM）、傅里叶红外光谱（FTIR）和X射线荧光光谱（XRF）分析仪等表征对材料进行分析，结果表明，经改性的咖啡渣具有较大的比表面积和较高的表面粗糙度，同时含巯基团和含氧基团被成功负载，可以与铅离子进行络合，生成稳定的配合物。更多还原

【Abstract】 To explore the resource utilization approach of coffee grounds, a novel adsorbent was prepared via the graft modification of coffee grounds with L-cysteine and applied to the removal of heavy metal lead（Pb） from aqueous solutions. The research shows that L-cysteine-modified coffee grounds exhibit excellent adsorption performance for lead. Under the condition of adsorbent dosage of 2 g/L, initial pH of 4 and adsorption time of 1 h, the equilibrium adsorption capacity reaches 47.53 mg/g with a Pb²⁺ removal rate of 95.06%. Kinetic studies indicate that the pseudo-second-order kinetic model provides a better fit for the adsorption of Pb²⁺ by L-cysteine-modified coffee grounds, demonstrating that chemical adsorption dominates the entire adsorption process. Thermodynamic analysis reveals that the adsorption is a spontaneous endothermic reaction. The isothermal adsorption experimental data are well fitted with the Freundlich model, confirming that the adsorption occurs on a heterogeneous surface and follows a multimolecular layer adsorption pattern. The adsorbent was characterized by Brunauer-Emmett-Teller（BET） surface area and porosity analyzer, scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FTIR） and X-ray fluorescence spectroscopy（XRF）. The characterization results show that the modified coffee grounds possess a larger specific surface area and higher surface roughness. Meanwhile, thiol-containing and oxygen-containing functional groups are successfully grafted onto the surface of coffee grounds, which can complex with lead ions to form stable coordination complexes.更多还原