الملخص الإنجليزي
Dehydrated carbon (DC) was prepared from date palm leaflets via phosphoric acid treatment at 170 °C in the presence of air. Acidified DC was converted to activated carbon (AC) at 500 °C under nitrogen atmosphere. DC shows very low surface area (4.45 mʻgʻ!) with high content of surface functional groups on its surface compared to activated carbon that have high surface area (764 mg) with low surface functional groups. Both carbons were tested for the adsorption of Ibuprofen (IBU) and Diclofenac (DIC) by varying contact time, initial pH, concentration and temperature. Optimal adsorption pH was found to be 4.5 for IBU and 8.0 for DIC adsorption. These pH values were selected for kinetic and equilibrium studies. Equilibrium was reached within ~ 24 hours for both drugs on the carbons under investigation. Adsorption kinetics was found to follow well pseudo second order kinetic model with increased adsorption as temperature increased. Activation energy, Ea, was 11.6-22.6 kJ mol"? indicating the physical adsorption nature of both drugs onto both carbons. Equilibrium was found to increase with temperature increase from 25 °C to 45 °C. The equilibrium adsorption fitted Langmuir isotherm more than Freundlich. Thermodynamic parameters showed that the adsorption of drugs is spontaneous and endothermic in nature with physical adsorption forces dominating the removal processes. AC showed ~100% removal of DIC and IBU using 9.6 and 6.4 g per 1 L of both drug (100 ppm), respectively. However, DC showed ~90% removal of DIC and IBU using 9.6 and 6.4 g per 1L of the drug solution (100 ppm), respectively. Even with its very low surface area, DC shows competitive adsorption capability to AC. Drug desorption from loaded carbons showed better performance for DC than AC. From this study, dehydrated carbon proved to be as efficient as activated carbon in removing pharmaceutical drugs from aqueous solution, however, with better desorption properties than activated carbons.
