Current Environmental Engineering Send Orders for Reprints to reprints@benthamscience.net Current Environmental Engineering, 2019, 6, 159-172 RESEARCH ARTICLE Application of Calophyllum inophyllum Seed Husk as a Low-Cost Biosorbent for Efficient Removal of Heavy Metals from Wastewater for a Safer Environment 159 Adeniyi A. Adenuga * , John Adekunle O. Oyekunle, and Olufemi D. Amos Department of Chemistry, Obafemi Awolowo University, Ile Ife, 220005, Nigeria 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 in- ophyllum seed husk as biosorbent for simultaneous removal of heavy metals from aque- ous solutions and investigated the removal efficiencies of the biosorbent for Pb 2+ and Cd 2+ in wastewater samples. Methods: The dependence of the adsorption process on pH, adsorbent dosage, tempera- ture, initial metal ions concentration, and contact time was evaluated in a batch system by determining the degree of adsorption of Pb 2+ and Cd 2+ 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 adsorp- tion 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 Pb 2+ and Cd 2+ , 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. A R T I C L E H I S T O R Y Received: April 17, 2019 Revised: May 16, 2019 Accepted: May 17, 2019 DOI: 10.2174/2212717806666190611150136 Keywords: Agricultural waste, seed husk, adsorption Isotherms, wastewater, Lead, cadmium. 1. INTRODUCTION Water, a basic necessity of life, becomes pollut- ed when potentially toxic foreign matters are di- rectly or indirectly introduced into it at levels that deteriorate its quality and compromise its *Address correspondence to this author at the Department of Chemistry, Obafemi Awolowo University, Ile Ife, 220005, Nigeria; Tel: +234 811 264 5950; E-mail: adenugaa@oauife.edu.ng usefulness for specified purposes [1-3]. Over the years, the discharge of untreated metal- contaminated wastewater, as a result of rapid in- dustrialisation and urbanisation, has been on the rise and this has made the levels of metallic xeno- biotics become an issue of immense concern glob- ally. The issue of indiscriminate discharge of un- treated or inadequately treated wastewater by in- dustries into the already fragile environments is on the rise in many developing countries, partly due 2212-7186/19 $58.00+.00 © 2019 Bentham Science Publishers