Informatics Publishing Limited

Ming Chen ¹, Qingyunq Cai ¹, Jinxia Nie ¹, Qinghua Zeng ²

Affiliations
1 School of Resource and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, CN
2 University of Western Sydney, Sydney, AU

Abstract

Eight bacterial strains were isolated from lead-cadmium contaminated soil samples obtained from a Tungsten mine. Pb²⁺ and Cd²⁺ adsorption abilities of the isolated strains were screened. One isolate, referred to as Strains S, was selected for further study because of its relatively high adsorption ability. Five factors affecting adsorption of Pb²⁺ and Cd²⁺ were studied, namely, the initial concentration of Pb²⁺ or Cd²⁺, temperature, pH, biomass of Strains S, and adsorption time. Results indicated that Strains S best adsorbed Pb²⁺ when the initial concentration of Pb²⁺ was 100 mg/L, temperature was 35°C, pH was 6.5, dosage was 0.1 g, and adsorption time was 20 min. In contrast, Strain S best adsorbed Cd²⁺ at an initial Cd²⁺ concentration of 100 mg/L, temperature of 40°C, pH 6.5, dosage of 0.1 g, and adsorption time of 20 min. The experimental data were fitted to the Langmuir and Freundlich adsorption isotherm models, and the results indicated that the Langmuir model better fitted the experimental data. The results of infrared spectroscopy revealed that the functional groups involved in adsorption of Cd²⁺ and Pb²⁺ were -OH, -NH₂, -S=O and -P=O. Using 16S rDNA sequencing and phenotypic properties test, Strains S was identified as Enterobacter sp.

Keywords

Lead, Cadmium, Adsorption Characteristics, Tungsten Mine.

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