Jaslin Ikhsan, Seti Fani
The abundant sugarcane bagasse from the sugar mills can be a waste that endangers the environment. In fact the sugarcane bagasse contains silica that is useful as an adsorbent. This research is focused on the synthesis of silica from sugarcane bagasse and its application as an adsorbent of nitrate ions in view of the binding process between silica and nitrate ions. The silica from the baggase is characterized by FTIR and XRD. It is compared to Kiesel gel type 60 (Merck). The adsorption data is collected by varying the nitrate ions concentration. The proton stoichiometry (χ) and the amount of the added H+ or OH- required to maintain a constant pH value of 7.0 during the adsorption experiments are calculated. All experiments are conducted at a room temperature within an equilibrium time of 30 min. The results obtained are described by the isotherm equations of Langmuir, Freundlich, and Dubinin-Radushkevich. It is found that they fit very well the Freundlich isotherm, which in turn indicates the formation of a multilayer coverage of the silica surface sites by nitrate ions. The energy involved in the adsorption process calculated by the Dubinin-Radushkevich model amounts to 5.61 kJ/mole. The χ value obtained shows that the adsorption process does not involve a significant amount of protons. The three models used in this research provide the conlcusion that the nitrate ions adsorptioon is a physical one. © 2019 University of Chemical Technology and Metallurgy.
Chemistry Education Department, Universitas Negeri Yogyakarta, Jl. Colombo No. 1, Yogyakarta, 55281, Indonesia
