Evaluation on adsorption characterization of Cr3+, Ni2+, Pb2+, Cd2+, Fe3+, and Zn2+ materials using delonix regia impacted by tannery effluents

ABSTRACT The extensive discharge of tannery effluents containing heavy metals into the environment severely threatens ecosystems and public health. This study assesses the adsorption efficiency of Delonix regia as a sustainable adsorbent for removing heavy metals from tannery effluents. Operating conditions, including pH, interaction time, adsorptive dosage, and preliminary metal attentions, were systematically enhanced to enhance the adsorption process. Analytical results reveal that heavy metals such as Chromium (Cr3+), Nickel (Ni2+), Lead (Pb2+), Cadmium (Cd2+), Iron (Fe3+), and Zinc (Zn2+) frequently exceed permissible limits set by WHO and US-EPA standards in effluents, with Cr and Cd surpassing limits in 75% and 50% of studies, respectively. The adsorption experiments demonstrate that Delonix regia effectively reduces metal concentrations to acceptable levels under optimal conditions, with higher adsorption capacities for Cr and Pb. The adsorbent’s recovery potential was assessed using desorption techniques, ensuring its reusability and economic feasibility. Furthermore, the study highlights the influence of effluents’ physicochemical properties (e.g., temperature, turbidity, conductivity) on adsorption efficiency, providing insights into real-world application scenarios. Comparative research with present adsorbents confirms the viability of Delonix regia as an ecological and profitable replacement for heavy metal cleanup. This paper underlines the importance of including recovery mechanisms and maximising operational parameters to improve the sustainability of effluent treatment systems. By offering scalable solutions for companies wishing to follow rigorous environmental policies, findings help to raise knowledge of green remedial tactics.