Preparation of magnetite coated humic acid (Fe3O4-HA) as malachite green dye adsorbent

Abstract

Magnetite (Fe3O4) coating using humic acid (HA) to form Fe3O4/HA as malachite green dye adsorbent has been carried out. Humic acid was obtained from the isolation of peat soil from Rawa Pening, Ambarawa, Central Java, using the conventional alkaline extraction method. Synthesis of magnetite and Fe3O4/HA by coprecipitation method under alkaline conditions using NaOH. The characterization using Fourier Transform Infrared (FTIR) shows a bond between carboxylate groups in HA and Fe on magnetite, which proves that HA coating on magnetite surfaces has been successfully carried out. The characterization results using X-Ray Diffraction (XRD) showed that the coating of HA on magnetite did not change its phase shape but decreased its peak intensity. The results of characterization using a Surface Area Analyzer (SAA) showed that HA coating increased the surface area of Fe3O4. The optimum adsorption of malachite green by HA occurred at pH 3 for 60 minutes, with a concentration of 96.95 mg/L. Magnetite adsorbs optimally at pH 7 for 90 minutes and a concentration of 83.48 mg/L, while Fe3O4/HA occurs at pH 3 for 90 minutes with 104.15 mg/L.