ABUAH IKECHUKWU VALENTINE

This study assesses the efficiency of activated carbon in treating copper nitrate contaminated borehole water for domestic and irrigation purposes. The increasing contamination of groundwater by heavy metals and nitrates poses serious environmental and public health concerns, particularly in developing regions. The aim of this research was to evaluate the ability of activated carbon to reduce copper and nitrate concentrations in borehole water and to determine its suitability for sustainable water reuse. Borehole water samples contaminated with copper ions (Cu²⁺) and nitrate were treated with activated carbon at different contact times under laboratory conditions. Physicochemical parameters such as pH, electrical conductivity, turbidity, copper concentration, and nitrate concentration were analyzed before and after treatment using standard laboratory methods. Adsorption behavior was evaluated using Langmuir and Freundlich isotherm models, while adsorption kinetics were investigated using pseudo-first-order and pseudo-second-order kinetic models to understand the mechanism of adsorption. The results showed a significant reduction in copper and nitrate concentrations after treatment with activated carbon. The Langmuir isotherm model showed the best fit with correlation coefficients (R²) of 0.9949 for copper and 0.9861 for nitrate, indicating monolayer adsorption on a homogeneous surface. The Freundlich model also showed good correlations (R² = 0.9500 for copper and 0.9624 for nitrate). Kinetic analysis revealed that the pseudo-second- order model better described the adsorption process, with R² values of 0.9824 for copper and 0.8049 for nitrate. The treated water quality improved and was suitable for irrigation and moderately improved for domestic use, confirming that activated carbon is an effective and low-cost adsorbent for reducing copper nitrate contamination in borehole water