Characterization and Potential of Samanea saman-Activated Carbon on Adsorption of Copper from an Aqueous Solution

Abstract

The mining and electroplating industries have resulted in the contamination of the environment with heavy metal. This has resulted in a serious threat to the ecological environment and human health due to the presence of copper pollution. To address this issue, extensive efforts have been made to develop effective methods for removing contaminants, particularly heavy metal, and Samanea saman (SS) was selected as precursor production of activated carbon. Therefore, this study is aimed at investigating Samanea saman-activated carbon (SSAC) to remove copper from an aqueous solution. SS was chemically activated by potassium carbonate and carbonized at 600°C for 5 hours, while SSAC was characterized by scanning electron microscopy-energy dispersive X-ray (SEM-EDS), Fourier-transform infrared (FTIR), and proximate tests. Copper adsorption on SSAC was evaluated by the Langmuir, Freundlich, Langmuir, Freundlich, Redlich-Peterson, Harkin-Jura, and Jovanovic models. Pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models were used to identify adsorption process mechanism. SEM-EDS results presented that the pore of SSAC was heterogeneous, irregular in shape, and mesopore. In addition, FTIR analysis identified the main functional groups present in SSAC as C-H, C-O-C, and C-O. The proximate test conducted on SSAC determined the water content, volatile matter, ash content, and fixed carbon to be 0.61%, 22.26%, 9.77%, and 67.97%, respectively. The results showed that SSAC exhibited exceptional performance with copper removal efficiency of 99.49% under an adsorbent mass of 0.25 g, a reaction time of 30 minutes, and a concentration of 10 mg/L. Isotherm adsorption of SSAC followed the Redlich-Peterson model with an adsorption capacity (Qm) of 0.663 mg/g, correlation value ( $R^2$ ) of 0.9992, and pseudo-second-order pattern $R^2=0.9997$ . Therefore, SSAC can be proposed as a potential and economical biomaterial to treat heavy metal in wastewater.