Investigation of Aqueous Cr(VI) Adsorption Characteristics of Orange Peels Powder

Abstract

This study deals with the application of orange peels powder (OPP) for Cr(VI) adsorption from aqueous solutions at room temperature. The OPP was prepared and then characterized by FTIR and SEM for various functional groups and surface morphology, respectively. The powder surface contains different functional groups necessary for adsorption. The powder was of highly porous nature which is a prerequisite for sorption. The variation of adsorption efficiency of the adsorbent with different influencing parameters like pH of solution, contact time, adsorbate concentration and adsorbent dose was studied. The maximum adsorption was achieved at interaction time of 50 min and pH 7 of solution. The data obtained at equilibrium best fitted into Langmuir adsorption isotherm as compared to Freundlich adsorption isotherm. The maximum value of monolayer adsorption capacity was 4.69 mg g^–1. The Langmuir separation factor “r” was from 0.193 to 0.0383 for all the initial concentrations suggested favorable adsorption of Cr(VI) on OPP. The adsorption process was found to occur via pseudo-second order equation as revealed from kinetic studies.