Adsorption of Au(III) ions on xanthated crosslinked chitosan resin in hydrochloric acid medium
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Rare Met. DOI 10.1007/s12598-014-0279-2
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Adsorption of Au(III) ions on xanthated crosslinked chitosan resin in hydrochloric acid medium Miao Zeng, Ting-An Zhang*, Guo-Zhi Lv, Zhi-He Dou, Yan Liu, Ying Zhang
Received: 28 April 2013 / Revised: 9 September 2013 / Accepted: 10 April 2014 Ó The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg 2014
Abstract Xanthated crosslinked chitosan (XCCS) resin prepared under microwave irradiation were used for adsorbing Au(III) ions in hydrochloric acid medium. The influence of pH and temperature on the adsorption capacity of XCCS was investigated. The original XCCS and the loaded XCCS were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The results indicate that the XCCS has ability to adsorb Au(III) ions and the maximum adsorption capacity of Au(III) ions on XCCS is observed at pH 1 and 20 °C. The data of batch adsorption tests are fitted to kinetic models and isotherm models, respectively. The kinetics of adsorption process is found to follow pseudo-second-order kinetic rate model, and equilibrium data agree very well with the Langmuir model. Thermodynamic calculation of the Au(III) ions adsorption process indicates that the adsorption process is spontaneous and endothermic. Keywords Xanthated crosslinked chitosan; Adsorption; Au(III) ions
1 Introduction Precious metals which are always named as the vitamin of temporary industry play a significant role in many fields such as catalysts in various industrial processes including electronic industry, aerospace industry, and communication
M. Zeng, T.-A. Zhang*, G.-Z. Lv, Z.-H. Dou, Y. Liu, Y. Zhang Key Laboratory of Ecological Utilization of Multi-metal Intergrown Ores of Ministry of Education, School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China e-mail: [email protected]
and national defense industry [1–3]. With the rapid development of world economics, the demand and consumption of precious metals are continuously increasing [4]. Since the world’s precious metal resources are limited, the recovery from secondary resources such as the precious metal manufacturing industry production and those effluents arising from their production processes is becoming more and more important. As an effective recovery method, the adsorption technique is commonly used for the removal of precious metals from aqueous solutions with low concentration due to high economic benefits and no secondary pollution. Chitosan is a natural biopolymer, which can adsorb heavy metals from ground water and industrial effluents due to its ability of forming complexes with transition metal ions [5, 6]. According to the soft hard acid–basic (SHAB) theory [7, 8], the precious metal ions such as Au(III), Ag(I), Pt(IV), and Pd(II), belong to soft acid and tend to form stable chelate with ligands contained N/S atoms such as thiol, thiocarbamate, thiourea, thioether, azo, nitrile, amide, amino, and other soft bases. The research on using th
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