Equilibrium, Thermodynamic and Kinetic studies for biosorption of Terasil Brown 2RFL from contaminated water using economical biomaterial

Abstract

The present study investigated the potential of native and modified sugarcane bagasse for the biosorption of Terasil Brown 2RFLfrom wastewater. The novelty of present work is the preparation of cost effective, efficient and eco friendly biosorbent for the removal of disperse dye  using  waste sugarcane bagasse after different simple and inexpensive physical and chemical treatments. The optimization of various physicochemical factors like pH, biosorbent dose, contact time, initial dye concentration and temperature was carried out in batch mode. It was observed that the biosorption capacity of native, CTAB treated and immobilized biosorbent was decreased from     54.78 to 34, 60.56 to 39.1 and 27.34 to 18.65 mg/g by decreasing pH from 2 to 9. The optimum pH was found to be 2. The reduction in biosorption of disperse dye from 75.4 to 12, 87.59 to 23.44 and 35.66 to 10.78 mg/g was found for native, pretreated and immobilized biosorbent by increasing the dose of  biosorbent from 0.05 to 0.3g.  Kinetic study showed the increase of dye removal by increasing the time from 5 to 90 min for native, CTAB treated and immobilized sugarcane bagasse respectively and there was not any effect on removal was observed after 90 min. At 90 min, the obtained biosorption capacities were 78.99, 89.22 and 38.99 mg/g for native, pretreated and immobilized biosorbent respectively. From the equilibrium study, it was found that the biosorption capacity was increased from 13.88 to 85.67, 20.88 to 94.65 and 10 to 56.77 mg/g by increasing the initial dye concentration from 10 to 100 mg/L. Thermodynamic study revealed the reduction in biosorption capacity from 76.55 to 49, 89.87 to 60 and 35 to 15 mg/g by increasing the temperature from 30 to 60 oC. The 0.05 g, 90 min, 100 mg/L and 30 oC were observed as optimum environmental conditions to attain the maximum removal of disperse dye from contaminated water using native, pretreated and immobilized sugarcane bagasse. The effect of salt, heavy metal ions was also studied on biosorption capacity to make this process more applicable on industrial scale because the contaminated water which discharged from industries mostly contained these ingredients in it. The well fitted equilibrium and kinetic models were found to be Langmuir and pseudo-second-order. Thermodynamic study showed the spontaneous and exothermic nature of biosorption process. The desorption study was also done to make this study more economical and environment friendly. From comparison of native and different modified forms of sugarcane bagasse, it was estimated that the CTAB treated sugarcane bagasse could be used as an efficient, environment friendly and cost effective biosorbent for the removal of Terasil Brown 2RFL from aqueous solution.