Ahmadiansyah, Diah Mardiana, Akhmad Sabarudin
Coconut shells, one of the abundant organic wastes from agriculture and plantation systems, can be converted into biochar and used as high-efficiency materials for certain applications. In this work, we prepared biochar from coconut shells by the fast pyrolysis method at 700?°C for 3?h, which is further activated by KOH at a ratio of 0.75:1 (w/w). The composite MnO2/biochar was synthesized by the sonochemical-assisted co-precipitation method at various pHs (3, 5, 7, 9, and 11), temperatures (60 and 80?°C), and times (1, 2, and 3?h) using the fixed composition of MnO2 and Biochar (1:1, w/w). Higher pH (pH 11) and temperature (80?°C) accompanied with shorter reaction time (1h) resulted in the highest amount of Pb(II) adsorbed. Based on XRD results at angle positions 37.1°, 42.6°, and 56.2° with a wide band, it shows that the amorphous MnO2/Biochar composite compound was successfully synthesized. The composite was applied as an adsorbent for Pb(II) removal from aqueous solutions. The isothermal adsorption was studied by the Langmuir and Freundlich models with R2 yields of 0.9924 and 0.9943, respectively. Such results indicated that the MnO2/Biochar nanocomposite has good potential for environmental purposes as it has the adsorption capacity for Pb(II) ion of 104.38?mg/g under optimum conditions. © 2023 Author(s).
Department of Chemistry, Faculty of Science, Brawijaya University, Malang, 65145, Indonesia; Resesarch Center for Advanced System and Material Technology, Brawijaya University, Malang, 65145, Indonesia