JOURNAL OF ENVIRONMENTAL PROTECTION SCIENCE (2007), Vol. 1, pp. 62 – 74. Improved Adsorption Capacity of Commercially Available Activated Carbon Norit ROW 0.8 Supra with Thermal Treatment for Phenol Removal Marlistya Citraningrum, Gunawan, Nani Indraswati, Suryadi Ismadji* Department of Chemical Engineering, Widya Mandala Surabaya Catholic University Kalijudan 37, Surabaya 60114, Indonesia __________________________________________________________________________________ Abstract In this study, NORIT granular activated carbon was modified by thermal treatment in order to increase the adsorption capacity of activated carbon. The treatment was done under nitrogen flow at various temperatures, and caused the amount of surface basic groups of the carbon increased significantly. Boehm titration, FTIR, pH DRIFT, N 2 adsorption isotherm, DFT, SEM, and XRD were used to characterize the activated carbons. The adsorption capacity was studied by phenol adsorption in different pH of solutions. It was found that the higher the treatment temperature is, the more basic the surface of activated carbon becomes, and the more phenol is absorbed. The adsorption is generally better at pH solution above the pH pzc . The Langmuir, Freundlich, and Dubinin-Raduskevich isotherm models were used to describe the equilibria data, and the Dubinin-Raduskevich isotherm model agrees with the experimental data well. Keywords: Activated carbon, surface chemistry, thermal treatment, phenol. JEPS (2007), Vol. 1, pp. 62 – 74. __________________________________________________________________________________ Introduction Activated carbon (AC) is a porous material prepared by several activation methods and used for adsorption due to its high surface area. It is a collective name for a group of porous carbon manufactured either by treatment of carbon with gases, or by carbonization of carbonaceous materials with simultaneous activation by chemical treatment [1]. AC can be subdivided into two broad categories – liquid- phase carbons used for removal of impurities from solution, and vapor-phase carbons used for the removal of gaseous contaminants and condensable vapors from gas streams [2]. According to its pore size, activated carbon can be classified as follows: 1) macropores, with diameter > 50 nm; 2) mesopores, with diameter between 2 and 50 nm; and 3) micropores, with diameter < 2 nm. All three pore sizes usually exist in activated carbons; the only difference is the distribution of these pores. Phenol belongs to a group of common contaminants found in wastewater. This toxic weak acid causes an unpleasant taste and odor even at low concentrations in water. Phenol is widely used in industry as an intermediate in chemical manufacturing, slimicide, disinfectant, and is used in the manufacture of resins, plastics, fibers, adhesives, iron, steel, aluminum, leather, and rubber [3,4]. It is also released from the decomposition of organic waste. Potential health impacts associated with phenols include cardiovascular or blood toxicity, developmental toxicity, gastrointestinal or liver toxicity, kidney toxicity, neurotoxicity, reproductive toxicity, respiratory toxicity, skin sensitivity, eye irritant, nausea, and even coma. Adsorption using activated carbon is one of the common procedures used to remove phenols in wastewater, but the adsorption capacity of activated carbons are influenced by many factors such as the pore size distribution and the surface chemistry [5]. For adsorption of organic compounds in aqueous phase, the surface chemistry and the *To whom all correspondence should be addressed: Tel: + 86-10- 62751923; Fax: + 86-10-62751923; E-mail: Email: suryadi@mail.wima.ac.id, suryadiismadji@yahoo.com, Tel: 62-31- 3891264, fax: 62-31-3891267 62