Activated Carbon in Bio decolorization of Azo Dye Methyl Red by Klebsiella quasipneumoniae GT۷

Industrial wastewater containing azo dyes poses a significant threat to natural water bodies, human health, and the environment. Despite the advantages of anaerobic methods for removing these pollutants, their industrial adoption is limited due to their time-consuming nature. This study assesses the effectiveness of activated carbon (AC) in accelerating the anaerobic reduction of the azo dye methyl red by Klebsiella quasipneumoniae GT۷. Decolorization experiments were conducted at ۳۰°C with initial dye concentrations of ۰.۱-۶ mM. Each experiment included three sets: inoculated medium with ۰.۵% AC, inoculated medium without AC, and non-inoculated medium with ۰.۵% AC. Samples were collected at specific time intervals, and centrifuged, and the supernatant was analyzed for residual dye using a spectrophotometer and thin-layer chromatography (TLC). In the non-inoculated medium, ۰.۵% AC achieved complete decolorization within minutes for dye concentrations below ۲ mM. At higher concentrations, efficiency decreased to ۹۵%-۶۲% over ۲۴ hours. The efficiency of dye adsorption was influenced by the maximum adsorption capacity of AC, as estimated by the Langmuir isotherm model (qmax ۲۲۷.۲۷ mg/g). In the inoculated medium without AC, complete decolorization occurred within less than ۴ hours. In the inoculated medium with AC, complete decolorization was achieved within ۶-۱۰ hours. TLC showed that in the presence of bacteria, with or without AC, the dye was reduced into aromatic amines, manifesting as fluorescent spots. Incorporating ۰.۵% AC during bacterial decolorization significantly enhanced the rate of dye reduction.

کلیدواژه ها:

Activated carbon ، Azo dye ، Klebsiella quasipneumoniae