Adsorption and removal of mercury ions from aqueous solution using raw and chemically modified Egyptian mandarin peel

In this study, the removal of mercury ions by Egyptian mandarin peel was investigated in aqueous solution. Three absorbents were derived from Egyptian mandarin peel, the first adsorbent was the raw peel (MP), the second one was pretreated mandarin peel with NaOH (MNa), and the third one was carbonized mandarin peel (MC). The extent of adsorption was studied as a function of pH, adsorbent dose, temperature, and contact time. Adsorption isotherms were modeled with Langnuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms. The data fitted well with the Langmuir isotherm and the maximum monolayer adsorption capacities were found to be 19.01, 23.26, and 34.84mg/g for MP, MNa, and MC, respectively. The kinetic data were analyzed using psudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The results indicated that Egyptian mandarin peel could be utilized as a low-cost adsorbent for mercury removal.