Utilization of Activated Carbon Produced from Agricultural Waste for Congo Red Adsorption

Abstract

This study investigates the preparation and application of activated carbon derived from almond seed shells (ASSAC), an agricultural waste material, for the removal of Congo Red (CR) dye from aqueous solutions. The activated carbon was characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-ray Spectroscopy (EDX), and Thermogravimetric Analysis (TGA). SEM images revealed a rough, porous structure in the activated carbon, indicating an increase in surface area and available adsorption sites after activation. FTIR analysis confirmed the presence of functional groups such as hydroxyl, carboxyl, and carbonyl, which enhance dye-adsorbent interactions. EDX analysis showed a high carbon content, suggesting successful carbonization, while TGA results indicated improved thermal stability of the activated material. Adsorption studies were carried out by varying parameters such as contact time, pH, adsorbent dosage, dye concentration, and temperature. The adsorption equilibrium data were best described by the Langmuir isotherm model, indicating monolayer adsorption, with a maximum adsorption capacity of 65.3 mg/g. The Freundlich model also showed a reasonable fit, suggesting surface heterogeneity. These findings highlight the potential of ASSAC as a low-cost, efficient, and sustainable adsorbent for the remediation of dye-contaminated wastewater.