Laboratory of Research: Process Engineering and Industrial Systems (LR11ES54), National School of Engineers of Gabes, University of Gabès, 6026, Gabès, Tunisia.
Environ Sci Pollut Res Int. 2016 Aug;23(16):15852-61. doi: 10.1007/s11356-015-4330-0. Epub 2015 Mar 21.
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.
最近，为了提高活性炭对特殊污染物的吸附性能，对活性炭表面结构进行修饰引起了广泛关注。含氧官能团被认为是活性炭表面吸附重金属的主要原因；其引入或增强需要特定的修饰和浸渍方法。在本工作中，采用臭氧（O3）气相和硝酸（HNO3）液相对橄榄石活性炭（COSAC）进行表面改性。采用 N2 吸附-脱附等温线、SEM、pHpzc、FTIR 和 Boehm 滴定对活性炭样品进行了表征。活性炭母体（COSAC）具有 1194 m²/g 的高比表面积，表现出主要的微孔结构。用硝酸和臭氧进行氧化处理会导致比表面积和微孔体积的降低，而这些酸性处理导致表面氧官能团的固定量增加，从而使碳表面更亲水。活性炭样品被用作从水溶液中去除 Co(II)、Ni(II)和 Cu(II)重金属离子的吸附剂基质。在 30°C 下获得吸附等温线，数据很好地符合 Redlich-Peterson 和 Langmuir 方程。结果表明，氧化后的 COSAC，特别是 COSAC(HNO3)，能够从水溶液中去除更多的 Co(II)、Cu(II)和 Ni(II)。硝酸氧化橄榄石活性炭的能力被测试用于从二元体系中去除金属离子，与单一体系相比，结果表明其具有重要的最大吸附量。
