Cobalt Ion Removal by Activated Carbon and Biochar Derived from Sargassum sp.

Activated carbon (AC) and biochar (BC) are porous substances derived from any carbonous material known to be highly effective adsorbents, making them valuable for removing pollutants like heavy metals. This study evaluated and compared the potential of AC and BC produced from <i>Sargassum</i> sp. by chemical activation and pyrolysis process for heavy metal removal, specifically Co²⁺ ions, to commercial AC (COMAC). Various techniques were employed to characterize these samples including FTIR, zeta potential, and surface area. Additionally, considering parameters such as pH, initial solution concentration, and the effect of AC/BC dose were investigated. The adsorption isotherm was also assessed. The results showed that a strong dependence of the adsorption capacity on pH was observed with optimal performance at ~6.8. Additionally, the optimal initial solution concentration was determined to be ~2 mmol/L. According to the Langmuir isotherm model, AC derived-<i>Sargassum</i> sp. exhibited maximum uptakes of 468.97 mg/g, higher than COMAC and BC. The experiment at different adsorbent dosages revealed that AC from <i>Sargassum</i> sp. outperformed other samples, with adsorption capacity observed at 94.94% as the dosage increased.