Affecting factors, equilibrium, kinetics and thermodynamics of bromide removal from aqueous solutions by MIEX resin
Affecting factors, equilibrium, kinetics and thermodynamics of bromide removal from aqueous solutions by MIEX resin
复制标题
DOI：
10.1016/j.cej.2011.11.096
复制
发表时间：
2012-02-01
影响因子：
15.1
通讯作者：
Han, Xu
中科院分区：
文献类型：
--
作者：
Ding, Lei;Deng, Huiping;Han, Xu
在饮用水消毒过程中，由于溴离子直接导致溴化消毒副产物的产生，因此有必要对原水中的溴离子进行去除。在间歇实验中研究了MIEX树脂对溴离子的吸附特性。溴离子初始浓度、接触时间、吸附剂用量、溶液pH值、共存阴离子等因素对溴离子的去除有显著影响。采用Langmuir、Freundlich、Temkin、Dubininin-Radushkevich和Redlich-Peterson五种等温模型对303 K时溴离子在MIEX树脂上的平衡数据进行了拟合。结果表明，吸附等温线可用Freundlich和Redlich-Peterson模型拟合。采用准一级和准二级动力学模型对溴离子在MIEX树脂上的吸附动力学过程进行了拟合。结果表明，MIEX对溴离子的吸附符合准二级动力学模型，表明MIEX对溴离子的吸附为化学吸附。采用颗粒内扩散模型进一步分析了溴离子在吸附过程中的扩散机理。结果表明，颗粒内扩散不是唯一的速率限制步骤。负Δ G值表明溴离子在MIEX树脂上的吸附在热力学上是可行的，并且是一个自发的过程。负的Δ H度和Δ S度表明吸附本质上是一个放热过程，吸附后固/液界面的无规度降低。(C)2011 Elsevier B. V.保留所有权利。
It is necessary to remove bromide from raw water owing to the fact that bromide directly leads to the brominated disinfection byproducts during the disinfection process for drinking water. The adsorption characteristics of bromide by MIEX resin are investigated in a batch mode. Some factors such as initial bromide concentration, contact time, adsorbent dosage, pH of solution and coexistent anions, have significant effect on bromide removal. Five isotherm models, namely, Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Redlich-Peterson, are used to fit the equilibrium data of bromide on MIEX resin at 303 K. The results show that the adsorption equilibrium can be well fitted by the Freundlich and Redlich-Peterson isotherm models. The pseudo first-order and second-order kinetics models are used to fit the kinetics process of bromide adsorption on MIEX resin. The results demonstrate the adsorption kinetics agree with the pseudo second-order model, indicating the adsorption of bromide on MIEX is chemical sorption. The intra-particle diffusion model is used to further analyze the diffusion mechanism of bromide during the adsorption process. The results imply that the intra-particle diffusion is not the only rate limiting step. The negative Delta G degrees values indicate that the adsorption of bromide on MIEX resin is thermodynamically feasible and is a spontaneous process. The negative Delta H degrees and Delta S degrees show that the adsorption is an exothermic process in nature and the randomness degree at the solid/liquid interface decreases after adsorption. (C) 2011 Elsevier B.V. All rights reserved.