Biosorption of astrazon red dye by the bacterium Rhodopseudomonas sp. strain 51ATA

Abstract

Astrazon red azodye that is still widely used in Turkey is released into the aquatic environment. Since these dyes are degradable into the toxic aromatic amines, they have become a public health and environmental concern. In this study, the biosorption of the Astrazon red dye from aqueous solutions on dehydrated cells of Rhodopseudomonas sp. 51ATA was studied as a function of each pH, temperature and initial dye concentration. Rhodopseudomons sp. 51ATA strain belongs to the Rhodopseudomonas species which is an eco-friendly photosynthetic and facultative anaerobic bacterium. The best uptake of Astrazon red was observed at pH 2.0 and the data obtained were applied to both Freundlich and Langmuir adsorption isotherms. The adsorption data provided an excellent fit to both isotherms and showed good agreement to Scatchard analysis at various temperatures. Freundlich isotherm showed good fit to the data at low temperatures while Langmuir model was suitable for describing the adsorption at higher temperatures. Therefore, from these data, we could report that Rhodopseudomonas sp. 51ATA strain is very efficient bacterium for the removal of dyes from wastewater.