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以磷酸锡晶体作为吸附剂,应用批量吸附法,研究了pH值、吸附时间、初始浓度、温度、离子强度等因素对去除水溶液中Cu2+的影响,通过热力学分析及电位滴定实验探讨了吸附机理.结果表明:磷酸锡对Cu2+的吸附量随着pH(3～6.5)以及吸附时间的增加而增大,吸附动力学过程符合准二级动力学模型.等温吸附数据用Langmuir方程拟合效果最好,20℃时饱和吸附量达到48.69mg/g.根据吸附自由能Es(kJ/mol)可知,吸附机理属于化学离子交换,即磷酸锡中的H+与溶液中的Cu2+发生了离子交换反应.该反应是一个自发的、吸热的过程,升温有利于吸附.在模拟海水中,高盐强度对磷酸锡吸附Cu2+有一定的不利影响,但幅度不大.当NaCl浓度达到0.6mol/L时,吸附量为21.87mg/g,是淡水介质时的93.3%,表明磷酸锡适用于去除养殖海水中的Cu2+.
The effects of pH value, adsorption time, initial concentration, temperature, ionic strength and other factors on the removal of Cu2 + in aqueous solution were studied by batch adsorption method. The adsorption mechanism was discussed by thermodynamic analysis and potentiometric titration experiments. The results show that the adsorption capacity of Cu2 + increases with the increase of pH (3 ~ 6.5) and adsorption time, and the adsorption kinetics follows the quasi-second order kinetic model. The Langmuir equation is best for isothermal adsorption data , The saturated adsorption capacity reaches 48.69mg / g at 20 ℃ .According to the adsorption free energy Es (kJ / mol), the adsorption mechanism belongs to chemical ion exchange, that is, H + ions in the tin phosphate react with Cu2 + in the solution. The reaction is a spontaneous and endothermic process, and the warming is favorable for the adsorption.In the simulated seawater, the high salt intensity has a certain adverse effect on the adsorption of Cu2 + by tin phosphate, but the magnitude is not significant.When the NaCl concentration reaches 0.6mol / L, The adsorption capacity was 21.87mg / g, which was 93.3% when freshwater medium, indicating that tin phosphate was suitable for removing Cu2 + in the cultured seawater.