Department of Chemical Engineering, Center of Excellence for Petro-Chemistry, AmirKabir University of Technology, No. 424, Hafez Ave, P.O. Box 15875-4413, Tehran, Iran E-mail:
Water Sci Technol. 2014;69(3):546-52. doi: 10.2166/wst.2013.741.
As an inexpensive method for modification of activated carbons (ACs), sulfurization has attracted significant attention. However, the resulting sulfurized activated carbons (SACs) often are less porous than the original ACs. In this work, we propose a new method for concurrent sulfurization/activation that can lead to preparation of SACs with more porosity than the corresponding non-sulfurized ACs. By using scanning electron microscopy, nitrogen adsorption/desorption, and iodine number experiments, the porous structure of the SACs has been compared with that of non-sulfurized ACs. The specific surface areas of SACs are higher than the corresponding ACs, regardless of the type of activation agents used. For instance, the specific surface area of SAC and AC activated with phosphoric acid is 1,637 and 1,338 m(2)/g, respectively. Additionally, sulfur contents and surface charges (pHpzc) of the SACs and non-sulfurized ACs are compared. In fact, the SACs have higher sulfur contents and more acidic surfaces. Furthermore, the Hg(II) adsorption capacity of SACs has been compared with the corresponding non-sulfurized ACs. The Hg(II) adsorption isotherms on a selected SAC is measured at different pH values and temperatures. Hg(II) adsorptions as high as 293 mg/g are observed by using SACs prepared by the method proposed in this study.
作为一种廉价的活性炭（ACs）改性方法，硫化已引起了广泛关注。然而，所得的硫化活性炭（SACs）通常比原始 ACs 的孔隙率更低。在这项工作中，我们提出了一种新的同时硫化/活化方法，可以制备比相应的未硫化 ACs 具有更多孔隙率的 SACs。通过使用扫描电子显微镜、氮气吸附/解吸和碘值实验，比较了 SACs 的多孔结构与未硫化 ACs 的多孔结构。无论使用哪种活化剂，SACs 的比表面积都高于相应的 ACs。例如，用磷酸活化的 SAC 和 AC 的比表面积分别为 1637 和 1338 m(2)/g。此外，还比较了 SACs 和未硫化 ACs 的硫含量和表面电荷（pHpzc）。实际上，SACs 的硫含量更高，表面酸性更强。此外，还比较了 SACs 和相应的未硫化 ACs 的 Hg(II)吸附能力。在不同 pH 值和温度下测量了选定的 SAC 上的 Hg(II)吸附等温线。通过使用本研究中提出的方法制备的 SACs，观察到高达 293 mg/g 的 Hg(II)吸附。
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