Mg-Al/Biochar Composite with Stable Structure for Malachite Green Adsorption from Aqueous Solutions
Arini Fousty Badri, Patimah Mega Syah Bahar Nur Siregar, Neza Rahayu Palapa, Risfidian Mohadi, Mardiyanto Mardiyanto, Aldes Lesbani
Abstract
Mg-Al-layered double hydroxide (LDH) was fabricated using a coprecipitation method at pH 10. Thereafter, Mg-Al-LDH was impregnated with biochar to manufacture a Mg-Al/Biochar composite. The composite was characterized using powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, N2 adsorption—desorption, thermogravimetry-differential thermal analysis (TG-DTA), and scanning electron microscopy (SEM) experiments, and was subsequently used for malachite green (MG) adsorption. MG adsorption experiments were performed in a batch system, and the effects of temperature and adsorption kinetic and isotherm parameters on the adsorption process were analyzed. The stability of Mg-Al/Biochar was evaluated using regeneration experiments over three cycles. The peaks at 11.47° (003), 22.86° (002), 34.69° (012), and 61.62° (116), in the XRD profile of Mg-Al/Biochar suggested that Mg-Al/Biochar was successfully fabricated. The surface area of Mg-Al/Biochar was up to five times larger than that of pristine Mg-Al-LDH. The adsorption of MG on Mg-Al/Biochar was dominated by interactions at the surface of the adsorbent and was classified as physical adsorption; moreover the maximum adsorption capacity ofMg-Al/Biochar was 70.922 mg/g. Furthermore, the MG removal of Mg-Al/Biochar during three successive adsorption cycles (i.e. 66.73%, 65.57%, and 65.77% for the first, second, and third adsorption cycle) did not change significantly, which indicated the stable structure of the adsorbent. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).