Removal of Zn(II) Ions Using an Adsorbent Derived from Aegle marmelos Correa (Bael) Shells

Zn(II) ions were adsorbed from a water-based solution using a thermally treated Aegle marmelos Corre shell referred to as Bael shell biochar (BSB), with a size range of 125 to 425 µm. The Aegle marmelos Correa (Bael) shell was thermally treated at 300 °C to prepare biochar. The experiment’s findings indicate that a pH of 7 with equilibrium duration of 180 min was ideal for removing Zn(II) from metal-contaminated water. Batch kinetic analysis revealed that the pseudo-second-order model preceded the adsorption. The Langmuir isotherm, which depicts monolayer adsorption, was found to better fit the metal adsorption at all tested temperatures. The results showed that BSB eliminated zinc ions as much as possible through adsorption, with a capacity of 16.28 mg/g at 303 K. After conducting desorption experiments with various effluents, it was found that 1.0 M HCl had the highest desorption percentage (93%). The thermodynamic values are approximate, 303 K is the optimal temperature among the tested temperatures, and zinc adsorption was exothermic and spontaneous. The BSB adsorbent was characterized before and after adsorption using FT-IR, FESEM and EDX studies, and the results showed that various functional groups present in the adsorbent were favorable for the removal of Zn(II) from water-based solutions.