title: Improvement of oxygen-containing functional groups on olive stones activated carbon by ozone and nitric acid for heavy metals removal from aqueous phase.
abstract: Recently, modification of surface structure of activated carbons in order to improve their adsorption performance toward especial pollutants has gained great interest. Oxygen-containing functional groups have been devoted as the main responsible for heavy metal binding on the activated carbon surface; their introduction or enhancement needs specific modification and impregnation methods. In the present work, olive stones activated carbon (COSAC) undergoes surface modifications in gaseous phase using ozone (O3) and in liquid phase using nitric acid (HNO3). The activated carbon samples were characterized using N2 adsorption-desorption isotherm, SEM, pHpzc, FTIR, and Boehm titration. The activated carbon parent (COSAC) has a high surface area of 1194 m(2)/g and shows a predominantly microporous structure. Oxidation treatments with nitric acid and ozone show a decrease in both specific surface area and micropore volumes, whereas these acidic treatments have led to a fixation of high amount of surface oxygen functional groups, thus making the carbon surface more hydrophilic. Activated carbon samples were used as an adsorbent matrix for the removal of Co(II), Ni(II), and Cu(II) heavy metal ions from aqueous solutions. Adsorption isotherms were obtained at 30 °C, and the data are well fitted to the Redlich-Peterson and Langmuir equation. Results show that oxidized COSACs, especially COSAC(HNO3), are capable to remove more Co(II), Cu(II), and Ni(II) from aqueous solution. Nitric acid-oxidized olive stones activated carbon was tested in its ability to remove metal ions from binary systems and results show an important maximum adsorbed amount as compared to single systems.
authors: Laboratory of Research: Process Engineering and Industrial Systems (LR11ES54), National School of Engineers of Gabes, University of Gabès, 6026, Gabès, Tunisia. bohlithouraya@gmail.com.
authors: Thouraya
authors: http://orcid.org/0000-0002-0583-6435
authors: T
authors: Bohli
authors: Laboratory of Research: Process Engineering and Industrial Systems (LR11ES54), National School of Engineers of Gabes, University of Gabès, 6026, Gabès, Tunisia.
authors: Abdelmottaleb
authors: A
authors: Ouederni
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry*; D017942:Nitric Acid / Q000032:analysis / Q000737:chemistry*; D031658:Olea; D010100:Oxygen / Q000737:chemistry*; D010126:Ozone; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002606:Charcoal; D017942:Nitric Acid; D010126:Ozone; D010100:Oxygen
keywords: Adsorption; Heavy metals; Olive stones activated carbon; Oxygen functional groups; Surface modification