Ivanets A I, Srivastava V, Kitikova N V, Shashkova I L, Sillanpää M
Institute of General and Inorganic Chemistry of National Academy of Sciences of Belarus, st. Surganova 9/1, 220072 Minsk, Belarus.
Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli, Finland.
Chemosphere. 2017 Mar;171:348-354. doi: 10.1016/j.chemosphere.2016.12.062. Epub 2016 Dec 20.
The aim of this work was to study the sorption kinetics and thermodynamics of Co(II) and Ni(II) from aqueous solutions by sorbents on the basis of hydrogen (PD-1) and tertiary (PD-2) Ca-Mg phosphates depending on the solution temperature and sorbents chemical composition. Kinetic studies of adsorption of Co(II) and Ni(II) ions onto samples of phosphate sorbents were performed in batch experiment at the temperatures 288, 303, 318 and 333 K. The sorbent dose was fixed at 10 g L, initial pH value 2.6, and contact time varied from 5 to 600 min. The kinetics of Co(II) and Ni(II) adsorption were analyzed by using pseudo-first order, pseudo-second order and intraparticle diffusion models. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) for the sorption of Co(II) and Ni(II) were determined using the Gibbs-Helmholtz equation. The calculated kinetic parameters and corresponding correlation coefficients revealed that Co(II) and Ni(II) uptake process followed the pseudo-second order rate expression. Thermodynamic studies confirmed the spontaneous and endothermic nature of removal process which indicate that sorption of Co(II) and Ni(II) ions onto both phosphate sorbents is favoured at higher temperatures and has the chemisorptive mechanism. The data thus obtained would be useful for practical application of the low cost and highly effective Ca-Mg phosphate sorbents.
本工作的目的是研究基于氢（PD - 1）和叔（PD - 2）钙镁磷酸盐的吸附剂对水溶液中Co(II)和Ni(II)的吸附动力学和热力学，该过程取决于溶液温度和吸附剂的化学组成。在288、303、318和333 K的温度下，通过间歇实验对Co(II)和Ni(II)离子在磷酸盐吸附剂样品上的吸附进行了动力学研究。吸附剂剂量固定为10 g/L，初始pH值为2.6，接触时间从5分钟变化到600分钟。使用准一级、准二级和颗粒内扩散模型分析了Co(II)和Ni(II)的吸附动力学。利用吉布斯 - 亥姆霍兹方程确定了Co(II)和Ni(II)吸附的热力学参数（ΔG°、ΔH°和ΔS°）。计算得到的动力学参数和相应的相关系数表明，Co(II)和Ni(II)的吸附过程遵循准二级速率表达式。热力学研究证实了去除过程的自发性和吸热性质，这表明在较高温度下，Co(II)和Ni(II)离子在两种磷酸盐吸附剂上的吸附是有利的，并且具有化学吸附机制。由此获得的数据将有助于低成本、高效的钙镁磷酸盐吸附剂的实际应用。
