Jaslin Ikhsan, Siti Sulastri, Sunarto
Sugarcane bagasse contains silica, which was separated and modified in this investigation. The silica was reacted by 3-(trimethoxysilyl)-1-propanethiol, and the product was oxidized to produce sulfonate-modified silica (SMS). The result of modification was accomplished by spectroscopic analysis of FTIR, XRD, and SEM-EDX. The SMS was used as adsorbent for adsorption kinetic and equilibrium of Ca2+ and Mg2+. The mechanism of the adsorption can be proposed from these experiments. Adsorption kinetic studied the adsorption of the cations as the function of contact time, and the data were evaluated by intra-particle diffusion model, Boyd equation, and Lagergren pseudo kinetic model. The calculated model fitted well to the experimental data and suggests that both Ca2+ and Mg2+ were adsorbed by SMS through external mass transfer, and were pseudo-second ordered. Adsorption equilibrium was evaluated using proton stoichiometry, and adsorption isotherms, the adsorption as the function of cation concentration, and the data were analysed using Dubinin-Radushkevich (DR)-Raduskovich. The results showed that the adsorption of Ca2+ onto SMS was through cation exchange and, that of Mg2+ onto SMS was via physisorption. © 2017 JPR Solutions.
Department of Chemistry Education, FMIPA, Universitas Negeri Yogyakarta, Jl. Colombo No. 1, Yogyakarta, Indonesia
