Crushed peach stone shells were impregnated with H3PO4 of increasing concentrations (30-70%) followed by heat treatment at 773 K for 3 h. Produced carbons (ACs) were characterized by N2 adsorption at 77 K using the BET-equation and the α-method. High surface area microporous ACs were obtained, with enhanced internal pore volume, as function of % H3PO4. Adsorption isotherms from aqueous solution were determined for methylene blue (MB) and p-nitrophenol (PNP), as representatives for dye and phenolics pollutant molecules. Application of the Langmuir model proved the high limiting capacity towards both solute molecules, MB was uptaken in increasing amounts as function of H3PO4 concentration and generated porosity. High removal of PNP was almost the same irrespective of porosity characteristics. Competitive adsorption of H2O molecules on the hydrophilic carbon surface seems to partially reduce the available area to the PNP molecules. Application of the pseudo-second order law described well the fast adsorption (≤ 120 min) at two initial dye concentrations.

• Amina A. Attia(National Research Centre)
• Badie S. Girgis(National Research Centre)
• Nady A.F. Tawfik(National Research Centre)