Abstract

Biosorption is a cheaper and more eco-friendly process for the removal of dyes from the aqueous media than filtration, chemical oxidation/reduction, electrochemical action, color irradiation, membrane technology, ozonation, etc. In this study, we have evaluated the efficiency of the fibers of Luffa cylindrica sponge for removing Alizarin Yellow-R dye from water. The fibers were chemically treated with NaOH for enhancing their sorption capacity. The sorption experiments were conducted batch wise and the following optimized conditions were recorded: 6.0 ppm initial concentration of the dye, 0.125 g biosorbent dosage, 100 minutes contact time, pH 3.0, 25 rpm speed and 20°C temperature. The equilibrium study was also conducted by fitting the sorption data to Langmuir and Freundlich isotherms. The maximum biosorption capacity of alkali treated Luffa cylindrica fibers was 3.59 mg/g, which was thrice to that with the non-treated one’s (1.07 mg/g). The kinetic studies manifested that the pseudo second order rate of reaction was applicable in the biosorption process. The FT-IR study of the biosorbent confirmed the presence of functional groups such as hydroxyl, carboxylic, etc. At low pH these functional groups became protonated and, through hydrogen bonding, more dye molecules were attached to the biosorbent surface. The SEM represented an etched and porous structure after alkali treatment with large surface area. Thus the following study revealed that the alkali treated fibers of Luffa cylindrica sponge can be used efficiently for removing Alizarin Yellow-R dye from the waste water.