Surface complexation of nickel on iron and aluminum oxides: A comparative study with single and dual site clays

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• 作者：Anushka Upamali Rajapaksha^a ; Meththika Vithanage^a ; ^{meththikavithanage@gmail.com} ; R. Weerasooriya^c ; C.B. Dissanayake^b
• 关键词：Diffuse double layer model ; Gibbsite ; Laterite ; Goethite ; Natural red earth
• 刊名：Colloids and Surfaces A ; Physicochemical and Engineering Aspects
• 出版年：2012
• 期刊代码：22_09277757
• 类别：ch
• 出版时间：5 July, 2012
• 卷：405
• 期：Complete
• 页码：79-87
• 文件大小：1056 K

摘要

Ni adsorption on various single and dual site clays (gibbsite, goethite, natural red earth and leterite) was determined using batch experiments as a function of pH, background electrolyte concentration and adsorbate loading. The experimental data was quantified by 2-pK surface complexation modeling using monodentate and bidentate surface reactions. Gibbsite and laterite showed higher retention of Ni compared to natural red earth (NRE) and goethite indicating high affinity to AlOH surface sites of all clays. The maximum adsorption density of 9.0 脳 10^鈭? mol m^鈭? was reported for gibbsite. All four sorbents showed a negligible variation with ionic strength. The Ni adsorption capacity, i.e., 螕Ni, varied with the type of sorbents used in accordance with the following order: 螕_Gibbsite Ni > 螕_Laterite Ni > 螕_NRE > 螕_Goethite Ni. In all cases, the estimated Gibb's free energy parameter showed that the Ni(II) adsorption was spontaneous.