Using Chemically Unprocessed Orange Peel to Effectively Remove Hg(II) Ions From Aqueous Solutions: Equivalent, Thermodynamic, And Kinetic Investigations

Abstract

This study looks at the capacity of raw orange peel (ROP) to adsorb Hg2+ ions from aqueous solutions. According to the results obtained, it is aimed at using ROPs more efficiently by recycling them. In this way, the usability of both ROP and other agricultural wastes in adsorption processes can be investigated. The effects of many variables on adsorption efficiency were investigated in the study, including initial metal ion concentration (MIC), contact time (CT), and pH. Under optimal operating conditions for Hg2+ ion adsorption, CT, solution pH, and initial concentration were determined to be 90 minutes, 3.08, and 180 mg/L, respectively. SEM, Fourier transform infrared spectroscopy (FT-IR), energy dispersion spectroscopy, and Brunauer, Emmett, and Teller (BET) analyses were used to examine the surface features of ROP. The isotherm values were found to be appropriate for the Langmuir isotherm model, indicating chemical absorption and likely process irreversibility. At 318, 308, and 298 K, the capacity of adsorption for the Hg2+ ion was calculated to be 66.225, 63.291 and 61.728 mg/g, respectively. The pseudo-second order (PSO), which exhibited the largest regression coefficient and best described the kinetic data for the removal of Hg2+ ions, according to thermodynamic studies, it was seen that the adsorption of Hg2+ ions on ROP is a natural and endothermic process. ROP, which is abundant throughout the world, can be used effectively in its natural state without any modification or chemical treatment, together with Hg2+ adsorption, to remove other heavy metals, dyestuffs, and toxic substances. ROP has been recognized as a potent and promising material for eliminating Hg2+ ions from the aquatic environment due to its characteristics such as high adsorption capability, cheap cost, and ease of availability.