磁性羟基氧化铝的制备及对水体中Cu^(2+)的吸附性能研究

Preparation of γ-AlOOH@SiO_2/Fe_3O_4 and its adsorption performance for Cu^(2+) from aqueous solution

采用水热法制备磁性羟基氧化铝(γ-AlOOH@SiO_2/Fe_3O_4),使用透射电子显微镜、X射线衍射、比表面积分析对其进行形貌表征,并研究了其对水体中Cu^(2+)的吸附性能。结果表明:γ-AlOOH@SiO_2/Fe_3O_4对水体中Cu^(2+)的吸附性能受pH、Cu^(2+)初始浓度、接触时间和温度的影响;γ-AlOOH@SiO_2/Fe_3O_4对Cu^(2+)的吸附符合Freundlich等温线方程,最大吸附量可达284.77mg/g;热力学分析表明,γ-AlOOH@SiO_2/Fe_3O_4对水体中Cu^(2+)的吸附过程是自发和吸热过程;动力学分析说明,该吸附过程遵循准二级动力学反应模型,该吸附过程为化学吸附,内扩散是整个吸附过程的限速步骤;Cu^(2+)吸附率随循环使用次数的增加稍有下降,吸附的Cu^(2+)可通过乙二胺四乙酸二钠(EDTA-2Na)脱附。

Magnetic adsorbentγ-AlOOH@SiO 2/Fe 3O 4 was synthesized via hydrothermal method.The structural and composition characteristics were analyzed using transmission electron microscope(TEM),X-ray diffraction(XRD),and brunauer emmet teller(BET)analysis.In the meantime,its adsorption performance for Cu 2+from aqueous solution was investigated.The results showed that the adsorption performance ofγ-AlOOH@SiO 2/Fe 3O 4 for Cu 2+from aqueous solution was affected by pH,initial Cu 2+concentration,contact time and temperature.The equilibrium data was best described by Freundlich multilayer adsorption isotherm model,and the maximum adsorption capacity was 284.77 mg/g.The thermodynamic analysis showed that the adsorption was a spontaneous and endothermic process.Theγ-AlOOH@SiO 2/Fe 3O 4 exhibited rapid adsorption rate,and the kinetic data followed the pseudo-second order model,indicating it was a chemical adsorption process,and intraparticle diffusion was the rate limiting step.Adsorption-desorption experiment showed that Cu 2+adsorption rate decreased slightly with the recycling use of the adsorbent,and the Cu 2+adsorbed could be desorbed by EDTA-2Na.