Jurnal Kimia Sains dan Aplikasi (May 2020)
Stability Improvement of Humic Acid as Sorbent through Magnetite and Chitin Modification
Abstract
Stability improvement of humic acid (HA) through modification of HA by chitin (HA-chitin) followed by a coating of HA-chitin on magnetite has been successfully performed. The coated magnetite (magnetite/HA-chitin) was conducted by the co-precipitation method, and the synthesized magnetite/HA-chitin was characterized by FT-IR, XRD, SEM-EDX, and VSM. The successful coated-magnetite by HA-chitin was proved by the appearance of a new band at 1627 cm-1 (FT-IR), the formation of a crystalline phase with characteristic 2θ of magnetite: 30.259° [220]; 35.64° [311]; 42.590° [400]; 57.280° [511]; and 62.896° [440] (XRD), an increasing of carbon content in magnetite/HA-chitin (SEM-EDX), and the ease of magnetite/HA-chitin being attracted to external magnetic fields with magnetic saturation strength 29.3 emu/g (VSM). Stability tests at pH 2.0 - 10.0 prove that magnetite/HA-chitin remains stable as a solid sorbent on average above 80%. Its application to Hg (II) sorption occurred optimum at pH 7.0, where 75.89% Hg (II) is sorbed on 0.1 g of sorbent and agreed well to the pseudo-second-order kinetics model of Ho.
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