Application of Calophyllum Inophyllum Seed Husk as a Low-cost Biosorbent for Efficient Removal of Heavy Metals from Wastewater for a Safer Environment

Abstract

Background: Effective treatment of wastewaters for potentially toxic metals especially at affordable cost is critical to the well-being of man and the environment. Objective: This study optimized the conditions for the application of Calophyllum inophyllum seed husk as biosorbent for simultaneous removal of heavy metals from aqueous solutions and investigated the removal efficiencies of the biosorbent for Pb2+ and Cd2+ in wastewater samples. Methods: The dependence of the adsorption process on pH, adsorbent dosage, temperature, initial metal ions concentration, and contact time was evaluated in a batch system by determining the degree of adsorption of Pb2+ and Cd2+ in simulated industrial wastewater before application of the biosorbent for metals cleanup in industrial and domestic wastewater samples. Results: The results showed that charring and microwave irradiation of the biosorbent produced the best performance. The pH of the aqueous solution played a crucial role in the performance of the biosorbent. Optimum adsorption for both metals occurred within the first 60 minutes of the process at pH value around 9. Kinetic studies of the process gave good correlation coefficients for a pseudo-second order kinetic model with adsorption data that fitted well into the Freundlich and Langmuir models but with Freundlich isotherm displaying better fitness. The adsorption capacities of the biosorbent were 42.19 and 22.47 mg/g for Pb2+ and Cd2+, respectively. Conclusion: The study concluded that the good adsorption capacities of Calophyllum inophyllum seed husk for the metals is an indications of its considerable potential as a low-cost biosorbent for simultaneous removal of potentially toxic metals from wastewaters.