Optimization of phenolic removal using oil palm empty fruit bunch (OPEFB) biosorbent

Abstract

This study investigates the optimization of biosorption of phenolic compound using treated OPEFB biosorbent. The surface of biosorbent was modified by physical or chemical treatment. The biosorption capacity for 2,3-dichlorophenol (2,3-DCP) are higher than 2-chlorophenol. Therefore, 2,3-DCP was chosen as adsorbate and 0.1M HCl treated OPEFB biosorbent was chosen as biosorbent in optimization. Full 2k factorial design and central composite design were carried out. A full 25-1 factorial design with five factors and two levels was used to screen the significant factor that influence the biosorption process. These results were applied in the optimization using Central Composite Design under Response Surface Design with three factor (initial 2,3-DCP concentration, pH of solution and OPEFB biosorbent dosage). The result of experiment gave the optimun condition for 2,3-DCP biosorption, where: initial concentration, pH and biosobent dosage were 200ppm, 5 and 0.1g, respectively). The maximun biosorption capacity was 13.65 mg/g. Langmuir biosorption isotherm was found to describe the biosorption of 2,3-DCP onto OPEFB biosorbent well at different initial concentration of 2,3-DCP solution. The Langmuir model described the system due to the monolayer coverage assumption on this model. Pseudo-second order was found fitted for the biosorption of 2,3-DCP onto OPEFB biosorbent. Thermodynamic constants of biosorption (ΔG°, ΔH° and ΔS°) were also evaluated, it indicated that biosorption of 2,3-DCP was exothermic and not spontaneous process.