分子遺伝医学

Evaluation of the Potential of Cadmium and Dyes Removal by Chitosan Obtained from Zygomycetes

Abstract

Freitas JHES, Mahnke LC, Estevam-Alves MHM, Santana KV, Campos-Takaki GM and Nascimento AE

Background: Treatment process for heavy metal and dye removal is a worrying factor in environmental health because it can contribute to the formation of new contaminants.

Objectives: To obtain and use chitosan from Zygomycetes for removal process of heavy metal (cadmium) and azodyes (Reactive Black and Remazol Red).

Methods: Chitosan was obtained by Rhizopus arrhizus UCP 402 and Mucor javanicus UCP 69 following the described method of Synowiecki and Al-Khateeb (1997) and submitted to removal tests for 18 h, with different concentrations of Cadmium (0.5-4 mM), Reactive Black (B) and Remazol Red (1-1000 mg/L) in orbital shaker under 150 rpm at 28°C. Then, the samples were submitted to spectrophotometry and chitosan exposed to the contaminants were submitted to electronic microscopy analysis.

Results: The efficiency of cadmium removal by Rhizopus arrhizus chitosan showed data of 92% (0.5 mM), 92.8% (1 mM), 75.9% (2 mM), 54% (3 mM) and 54.5% (4 mM) at pH 6.0. The efficiency of dyes removal by Mucor javanicus chitosan was about 100% (1 mg/L), 100% (10 mg/L), 100% (50 mg/L), 98% (100 mg/L), 55% (1000 mg/L) for Reactive Black (B) and 100% (1 mg/L), 100% (10 mg/L), 100% (50 mg/L), 98% (100 mg/L), 59% (1000 mg/L) for Remazol Red.

Conclusion: Chitosan obtained by the strains was capable of removing cadmium and the reactive dyes: Reactive Black (B) and Remazol Red in all conditions tested.