Journal of Environmental Biology

Characterization of biological iron sulfide composites and its application in the treatment of cadmium-contaminated wastewater

Yang Yang^1,2,3, Yifei Xie^1,2* and Xudong Li^1,2

¹Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China

²Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China

³University of Chinese Academy of Sciences, Beijing 100049, China

*Corresponding Author E-mail : xieyf@cib.ac.cn

Publication Data

Paper received:

19 September 2013

Revised received:

31 January 2014

Accepted:

25 March 2014

Abstract

A strain of sulfate reducing bacteria, which could generate biological iron sulfide composites, was applied for Cd (Ⅱ) removal from wastewater. The influence of biological iron sulfide composites dosage, initial pH and temperature on the rate of Cd (Ⅱ) removal from wastewater by biological iron sulfide composites were investigated. The microscopic morphological characteristics and elemental composition changes of the biological iron sulfide before and after treatment was compared, using scanning electron microscopy and energy-dispersive spectrometry, then the mechanism of Cd (Ⅱ) removal was explored. The results showed that Cd (Ⅱ) reduction rate increased with increase in dosage of biological iron sulfide composites and initial temperature. At 25℃, pH 4.0, with dosage of sulfide and cadmium ions molar equal to 99.93% Cd (Ⅱ) was removed from cadmium wastewater (100 mg l^-1), and the residual concentration of cadmium reached Chinese Integrated Wastewater Discharge Standard (GB8978-1996). The present study revealed that bio-precipitation of FeS, the main component of biological iron sulfide composites, played leading role in the process of Cd (Ⅱ) reduction. Therefore, it is prospective to apply biological iron sulfide composites in the emergency treatment of cadmium-contaminated wastewater. ?? 

 Key words

Biological iron sulfide composites, Bio-precipitation, Bio-sorption, Cadmium-contaminated wastewater, Energy-dispersive spectrometry 

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