An improved implementable process for the synthesis of zeolite 4A from bauxite tailings and its Cr3+ removal capacity

作者：Lei, Peng-cheng; Shen, Xian-jiang; Li, Yang; Guo, Min; Zhang, Mei^*

来源：International Journal of Minerals,Metallurgy and Materials, 2016, 23(7): 850-857.

DOI：10.1007/s12613-016-1300-6

• bauxite
• tailings
• zeolite
• trivalent chromium
• wastewater treatment

A simple and practical method for the synthesis of zeolite 4A from bauxite tailings is presented in this paper. Systematic investigations were carried out regarding the capacity of zeolite 4A to remove Cr(III) from aqueous solutions with relatively low initial concentrations of Cr(III) (5-100 mg center dot L-1). It is found that the new method is extremely cost-effective and can significantly contribute in decreasing environmental pollution caused by the dumping of bauxite tailings. The Cr(III) removal capacity highly depends on the initial pH value and concentration of Cr(III) in the solution. The maximum removal capacity of Cr(III) was evaluated to be 85.1 mg center dot g(-1) for zeolite 4A, measured at an initial pH value of 4 and an initial Cr(III) concentration of 5 mg center dot L-1. This approach enables a higher removal capacity at lower concentrations of Cr(III), which is a clear advantage over the chemical precipitation method. The removal mechanism of Cr(III) by zeolite 4A was examined. The results suggest that both ion exchange and the surface adsorption-crystallization reaction are critical steps. These two steps collectively resulted in the high removal capacity of zeolite 4A to remove Cr(III).

• 出版日期2016-7
• 单位北京科技大学