Abstract

This article reports batch adsorption of Eriochrome Black-T (EBT) dye from an aqueous solution onto NaOH Treated Rice Husk (TRH). The morphology of untreated and treated rice husk was studied by Scanning Electron Microscopy (SEM). Adsorption of EBT from an aqueous solution onto TRH was demonstrated by using Fourier Transform Infrared (FTIR) spectroscopy. The effect of operational parameters on the percentage removal of EBT from an aqueous solution and adsorption capacity was investigated in detail. The adsorptive removal of EBT from aqueous solution was increased with contact time, mass of TRH and temperature while declined with initial concentration of EBT aqueous solution. Similarly, adsorption capacity was enhanced from 0.71 to 1.61mg/g, 1.61 to 17.0mg/g and 1.41 to 1.68mg/g with increase in contact time, initial concentration of EBT aqueous solution and temperature respectively while decreased from 6.17 to 1.61mg/g with increase in mass of TRH. Adsorption kinetic study showed that adsorption of EBT onto TRH fitted well to pseudo-second-order kinetics because the value of correlation coefficient (R2= 0.996) was close to unity. Adsorption isotherms including Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Tempkin were applied to experimental data. Results suggested that experimental data fitted well to Freundlich adsorption isotherm. Adsorption thermodynamics study indicated that adsorption of EBT onto Treated Rice Husk (TRH) was endothermic process because the value of enthalpy (ΔHo= 20.57KJ/mol) was positive for it. Moreover, the negative values of Gibb’s free energy indicated that adsorption of EBT onto TRH was spontaneous process.

Keywords:Eriochrome Black-T (EBT); Endothermic process; Treated Rice Husk (TRH); Adsorption; Pseudo-second-order model