RAW COCONUT SHELL AS ADSORBENT FOR THE REMOVAL OF CONGO RED DYE FROM AQUEOUS SOLUTION

This research investigates the adsorption efficiency of coconut shell as a low-cost adsorbent for the removal of Congo red dye, an azo anionic dye, from aqueous solutions. The study evaluates the effect of adsorbent dosage, initial dye concentration, and contact time on the adsorption process. Adsorption isotherms were analyzed using Langmuir and Freundlich models, and kinetic studies were conducted to understand the adsorption mechanism. The results revealed that increasing the adsorbent dosage improved dye removal efficiency up to 0.8 g, beyond which a decrease was observed. The removal efficiency increased with initial dye concentration, reaching a peak at 40 ppm before a slight decrease. Langmuir isotherm analysis provided Q m = 1.3744 mg/g and R² = 0.3999, while Freundlich isotherm analysis yielded K f = 0.0112 and R² = 0.8471, indicating a better fit to the Freundlich model. Kinetic analysis showed that the adsorption followed the pseudo-second-order model with R² = 0.9259. These findings suggest that coconut shell is an effective and environmentally friendly adsorbent for removing Congo red dye from wastewater, with potential applications in industrial effluent treatment.