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| Orange peel was used as raw material to prepare two novel orange peel adsorbents MgOP and KOP. FTIR and SEM were used to characterize the adsorbents. Effects of pH, solid/liquid ratio, time and metal ion concentration on the Cu2+ adsorption were investigated by these two adsorbents. The equilibrium data were analyzed by using Langmuir, Freudlich, Temkin and Dubinin-Radushkevich models. Langmuir model provides the best correlation for the adsorption of Cu2+ by both MgOP and KOP, and the mono-layer adsorption capacity for Cu2+ removal by MOP and KOP are 40.37 and 59.77mg/g, respectively. The adsorbed amounts of Cu2+ increased with the increase in contact time and reached equilibrium within 20min. Kinetics data were analyzed using four adsorption kinetic models: the pseudo-first and second-order equations, the Elovich equation and intraparticle diffusion equation. The experimental data fit well the pseudo-second-order equation, which indicates the adsorption of Cu2+ by MgOP and KOP may follow a chemisorption mechanism. Thermodynamic studies showed the spontaneous, exothermic nature of the adsorption of Cu2+ by MgOP and KOP. |
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| Keywords:Adsorption;Isotherm;Kinetics;Cu2+;orange peel adsorbent |
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