Synthesis of Tender Coconut Waste-Derived Biochar for The Adsorption of Cadmium Ions from an Aqueous Solution

Abstract

Waste generation from the agricultural and forest processing sectors impacts macro- and micro-ecosystems. Utilization of waste for the synthesis of new products leads to sustainable waste management. By thermal degradation in an anoxic environment, these wastes are converted into a stable form of carbon termed biochar. Biochar is a carbon-rich, porous structure product that is inexpensive to produce and can be utilized for the adsorption of heavy metals from wastewater. Coconut (Cocos nucifera L) is the fruit of the coconut palm tree and is considered one of the most important crops. The production of biochar from the tender coconut waste using slow pyrolysis and its application for the removal of heavy metals (Cd2+) from wastewater. The analytical characterization was carried out with SEM, FTIR, XRD, BET, contact angle, electrical charge, and Raman spectra. Morphological analyses revealed that the biochar possesses a macro-mesoporous structures adsorption potential. XRD analysis revealed that increasing the crystallinity and graphitization of biochar, with sharp peaks around 22-26° indicating the formation of graphitic (002) planes. These structural investigations reveal that the produced biochar has adsorption capacity for heavy metals and dyes. The effect of contact time, metal concentration, and concentration of biochar has been investigated to understand the adsorption efficiency of biochar for the removal of Cd2+ in aqueous solution, utilizing the batch adsorption method. This research focuses on the adsorption of Cd²⁺ from aqueous solutions to advance sustainable water purification technologies and mitigate risks to environmental and human health.