Adsorption of Cu2+ From Aqueous Solution onto Agricultural Solid Waste-Mentha: Characterization, Isotherms, and Kinetic Studies

The present study explores the adsorption potential of Mentha piperita (an agricultural solid waste) to remove Cu2+ from aqueous solution. Different operational parameters such as the effect of pH, surfactant, equilibrium time, temperature, and initial metal ion concentrations were studied. Maximum adsorption of Cu2+ took place at pH range 5.0. Nearly 180 minutes are required to gain sorption equilibrium. The maximum adsorption capacity of mentha was 72.0 mg g(-1) for Cu2+. FTIR analysis pointed out the involvement of amine (-NH2) and carboxylic (-COOH) groups in the adsorption process. Simple Langmuir and Freundlich isotherm models were used to explain the sorption phenomenon. The adsorption dependence of Cu2+ on temperature was investigated and the thermodynamic parameters Delta S-0, Delta H-0, and Delta G(0) were calculated. The activation energy of the Cu2+ adsorption was calculated using the Arrhenius equation. The desorption of the adsorbent was found to be more than 90% by 0.1M NaCl.