Optimization and Modelling of Adsorption of Heavy Metals from Wastewater using Telfairia occidentalis and brewer's spent grain eco-friendly adsorbents

Abstract: In this work, the adsorption of heavy metal ions on Brewers' spent grain adsorbent (BSGA) and Telfairia occidentalis seed adsorbent (TOSA) was optimized and modelled kinetically. In a batch system, aqueous solutions were used to study the adsorption isotherms and kinetics of lead (Pb) and arsenic (As) ions onto TOSA and BSGA with reference to pH, adsorbent concentration, and settling time. The Design Expert version 12 was utilized in the response surface methodology (RSM) design of the experiment. According to experimental findings, the adsorption process was favoured by an acidic pH, increasing initial TOSA and BSGA concentrations, and longer settling times. For BSGA, the ideal dosage, pH, and settling time were found to be 4.12 g/l, 2.60, and 40.35 Min; for TOSA, they were 4.00 g/l, 4.00, and 40-min, respectively. The best removal efficiencies with BSGA were 63.33 per cent As and 83.37% Pb, and with TOSA, 86.36 per cent As and 85.37% Pb. The pseudo-first-order, pseudo-second-order, Elovich kinetic, and intra-particle diffusion model equations were applied to fit the experimental datasets for the adsorption of lead and arsenic ions under various conditions. From the model results, the rate constants of the first-order adsorption model (k1), the second-order kinetic model (k2), and the intra-particle diffusion rate constants (kint.) were determined. The experimental data fitted both the pseudo-second-order kinetic models and the Langmuir isotherm model very well, indicating that chemisorption is the adsorption mechanism. It also followed the intra-particle diffusion model for 20 minutes, after which it deviated indicating that intra-particle diffusion was not the sole rate-controlling step. Keywords: Adsorption, heavy metals, pollution, optimization, wastewater. Title: Optimization and Modelling of Adsorption of Heavy Metals from Wastewater using Telfairia occidentalis and brewer’s spent grain eco-friendly adsorbents Author: Harriet Ifeoma Anyaene, Dominic Okechukwu Onukwuli, Nkiruka Justina Edeani International Journal of Novel Research in Interdisciplinary Studies ISSN 2394-9716 Vol. 12, Issue 4, July 2025 - August 2025 Page No: 8-29 Novelty Journals Website: www.noveltyjournals.com Published Date: 23-July-2025 DOI: https://doi.org/10.5281/zenodo.16370573 Paper Download Link (Source) https://www.noveltyjournals.com/upload/paper/Optimization%20and%20Modelling-23072025-6.pdf