SI-2树脂对镍离子的静态吸附动力学

Static adsorption kinetics of nickel ions on SI-2 resin

为了研究电镀废水中镍的去除方法,采用离子交换树脂法吸附镍离子.首先对SI-2树脂的结构进行能谱分析和红外表征,然后探讨p H、初始浓度、温度和时间对镍离子吸附量的影响,在此基础上研究SI-2树脂对镍离子的等温吸附动力学特性.结果表明,SI-2树脂是无机硅胶型树脂,交联反应发生在树脂中的羟基上;p H=5时吸附最佳,树脂的最大吸附容量为3 000 mg/g;吸附过程中吉布斯自由能为-24.21 k J/mol,说明吸附过程是自发进行的;SI-2树脂对镍离子的吸附符合Langmuir和Freundlich模型;吸附过程符合拟二级动力学方程,吸附活化能为1.532 k J/mol.液膜扩散和颗粒内扩散是整个吸附过程的主要速率控制步骤.

To remove nickel from the electroplating waste water, the adsorption of nickel ions with ion exchange resin was investigated. First, the structure of SI-2 resin was characterized by energy disperse spectroscopy and infrared spectroscopy. Then the effects of p H, initial concentration, temperature and time on the adsorption of nickel ions were discussed and the isothermal adsorption and adsorption kinetics were studied.The results show that SI-2 resin is inorganic silicon and the reaction of crosslinking is on the hydroxyl of the resin;the maximum adsorption capacity of SI-2 resin is 3 000 mg / g when p H is 5; the gibbs free energy in the course of adsorption is-24.21 k J / mol, which demonstrates that the adsorption of nickel ions is a spontaneous adsorption process; the adsorption isotherm of nickel ions on the resin fits the model of Langmuir and Freundlich; the adsorption kinetics fits the pseudo-second-order equation well, and the activation energy is1.532 k J / mol. The adsorption process is controlled by film diffusion and intra particle diffusion.