HENRY DAVID AJIBOYE

Heavy metal pollution has become a critical environmental challenge, particularly due to the persistence and toxicity of metals such as copper in aquatic ecosystems. Conventional treatment methods for metal removal, including chemical precipitation, ion exchange, and membrane filtration, are often costly, inefficient at low metal concentrations, and produce secondary waste. In response, biosorption has emerged as an eco-friendly and sustainable alternative. This study investigates the potential of corn cobs, an abundant agricultural by-product, as a low-cost biosorbent for the removal of Cu2+ ions from aqueous solutions. The biosorbent was prepared through collection, washing, drying, crushing, and sieving of corn cobs to obtain uniform particle sizes. A Box-Behnken Design (BBD) under the Response Surface Methodology (RSM) framework was employed to optimize process parameters such as adsorbent dosage, contact time, and metal concentration. Experimental data were fitted to a quadratic model, and statistical analysis through ANOVA revealed that the model was highly significant (F-value = 116.31 , P < 0 .0001) with strong correlation coefficients (R2 = 0.9934, Adjusted R2 = 0.9848, Predicted R2 = 0.9135). Optimization results indicated maximum copper ion removal of 94.73% at the optimal conditions of 5.5g/L adsorbent dosage, 67.5 minutes contact time, and 6 mg/L initial metal concentration. The model validation confirmed close agreement between predicted and experimental results, demonstrating the reliability of the developed model. Thermogravimetric and differential thermal analyses (TGA/DTA) suggested that the corn cob biosorbent possessed good thermal stability, which supports its suitability for adsorption applications. The study concludes that corn cobs are an effective, sustainable, and economical biosorbent for copper ion removal from wastewater. It further recommends their potential application in small- to medium-scale industrial effluent treatment systems. Future research should focus on kinetic and isotherm modeling, column adsorption studies, and biosorbent modification to enhance adsorption efficiency and extend applicability to other heavy metals.