Abstract

The objective of this study was to investigate the use of manganese oxide nanocomposite to remove Cd(II) ions from aqueous phase. The adsorption behavior was studied as a function of adsorbent mass, solution pH, and contact time. The response surface methodology (RSM) by Box–Behnken design (BBD) was employed to evaluate the effects of these three parameters on the removal ratio of the Cd(II) ions. In process optimization, maximum removal of Cd(II) ions was achieved as 100% with adsorbent mass 1g, solution pH of 8.0, and contact time of 27 min. The kinetics of adsorption process by comparative analyses of the applicability of four kinetic models, pseudo-first-order, pseudo-second-order, intraparticle diffusion and Elovich kinetic model was investigated. The adsorption kinetics of Cd(II) ions was well fitted with the pseudo-second order kinetic model. Equilibrium isotherm studies revealed that Langmuir and Redlich–Peterson isotherm models fitted better with the adsorption data in describing the adsorption behavior. Adsorption of Cd(II) ions on adsorbent is favorably influenced by an increase in the temperature of the operation. Values of the change in standard heat of adsorption (ΔH°), and entropy (ΔS°) were positive. The negative value of change in standard Gibbs free energy (ΔG°), indicates the feasible and spontaneous of Cd(II) ions on manganese oxide nanocomposite.

中文翻译：

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用于从水相中吸附 Cd(II) 离子的氧化锰纳米复合材料：通过实验设计优化

摘要

本研究的目的是研究使用氧化锰纳米复合材料从水相中去除 Cd(II) 离子。吸附行为被研究为吸附剂质量、溶液 pH 值和接触时间的函数。采用 Box-Behnken 设计 (BBD) 的响应面方法 (RSM) 来评估这三个参数对 Cd(II) 离子去除率的影响。在工艺优化中，吸附剂质量为 1g，溶液 pH 值为 8.0，接触时间为 27 分钟时，Cd(II) 离子的最大去除率达到 100%。通过比较分析四种动力学模型的适用性，即拟一级动力学模型、拟二级动力学模型、颗粒内扩散模型和Elovich动力学模型，研究了吸附过程的动力学。Cd(II) 离子的吸附动力学与准二级动力学模型非常吻合。平衡等温线研究表明，Langmuir 和 Redlich-Peterson 等温线模型在描述吸附行为时更符合吸附数据。Cd(II)离子在吸附剂上的吸附受到操作温度升高的有利影响。标准吸附热的变化值 (ΔH °) 和熵 ( ΔS °) 为正。标准吉布斯自由能 (Δ G °)变化的负值表明 Cd(II) 离子在氧化锰纳米复合材料上的可行性和自发性。