الملخص الإنجليزي
Textile wastewater is considered as a potential source of aquatic pollution because of the presence of large concentration of toxic dyes. In this study, acidic, basic and hydrophobic activated carbons are prepared and tested for dye removal. Activated carbon (AC) was prepared from date palm leaflets using phosphoric acid activation and was oxidized using nitric acid to produce oxidized activated carbon (OAC). OAC was functionalized via amide coupling to produce hydrophobic activated carbons (HAC) and basic activated carbon (BAC) using n-propyl amine surfactants and propylene diamine, respectively. AC possesses high surface area (373 m~/g). It possesses less carbon-oxygen functional groups on its surface with slightly higher mesoporosity. Upon oxidation and surface functionalization, the surface area tremendously decreased and microporosity diminished. Two dyes brilliant cresyi blue (BCB) and alizarin yellow gg (AY gg) were tested for their removal from aqueous solution at different initial pH, time, concentration, temperature. Optimum adsorption took place at initial pH 6-7 for most of the carbons, thus, kinetic and equilibrium studies were carried out at initial pH of 6-7. Equilibrium time varies between 6 hours for HAC and 35 hours for AC. Adsorption data were found to follow the pseudo second order kinetic model. Adsorption rate was found to increase as temperature increases with the activation energy ranging between 10.5 - 27.6 kJ/mol for BCB and between 10.6 -23,1 kJ/mol for AY gg indicating the physical nature of dyes adsorption. The equilibrium studies show a better fitting to the Langmuir isotherm when compare to the Freundlich isotherm. Equilibrium adsorption was found to increase with the increase in temperature. Maximum sorption for BCB from solution were OAC (196 mg/g) and HAC (199 mg/g) at 45 °C. For AY gg, maximum adsorption took place for AC (192 mg/g) and HAC (185 mg/g) at 45 °C. Thermodynamic parameters show that the removal of both dyes is spontaneous and endothermic in nature with physical adsorption dominating removal from aqueous solution. The different carbons possess different dominating adsorption forces for dye removal
