Management of cadmium contamination in water by biochar and hydrochar modified from <i>Chlorella vulgaris</i> (Beijerinck)

ABSTRACT There are serious environmental risks associated with water pollution from chemical wastewater. This study aims to evaluate the effectiveness of modified C. vulgaris-derived biochar and hydrochar as efficient adsorbents for the removal of cadmium from aqueous solutions. Biochar and hydrochar derived from C. vulgaris were used for this purpose. Both materials were activated with potassium hydroxide, enhancing their adsorption capabilities. The adsorption process was evaluated through batch and column studies, examining various parameters such as contact time, pH, and initial cadmium concentration. Results indicate that both biochar and hydrochar demonstrated high efficiency in cadmium removal, with optimum conditions identified. Additionally, thermodynamic analysis indicated the spontaneous and endothermic nature of cadmium adsorption onto both materials. The values of ΔHo and ΔSo were determined for modified biochar, yielding 15.1 and 46.7 kJ/mol respectively and also for modified hydrochar, resulting in 14.9 and 46.5 kJ/mol respectively. This research provides valuable insights into the potential application of C. vulgaris derived biochar and hydrochar in wastewater remediation, offering an eco-friendly and cost-effective solution for cadmium contaminated sites. Furthermore, the study contributes to advancing scientific knowledge on modified biomass-derived materials for heavy metal removal, opening new avenues for research and innovation in environmental remediation technologies.