Ligand adsorption on an activated carbon for the removal of chromate ions from aqueous solutions
Ligand adsorption on an activated carbon for the removal of chromate ions from aqueous solutions
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DOI：
10.1021/la050549h
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发表时间：
2005-07-19
期刊：
影响因子：
3.9
通讯作者：
Carrasco-Marín, F
中科院分区：
文献类型：
--
作者：
García-Martín, J;López-Garzón, R;Carrasco-Marín, F
在这项工作中提出的结果是相关的设计的指导方针，以开发特定的性能在活性炭（AC）的表面。为此，合成了两种模型芳香族化合物，用电位滴定法研究了它们在水溶液中的电解行为。用孔隙率法测定了活性炭的结构特征。用程序升温脱附法和电位滴定法分别对活性炭表面的载氧功能和酸碱性进行了表征。测定了水溶液中芳香族化合物在活性炭上的吸附和脱附平衡，并根据前线轨道理论讨论了吸附和脱附之间的滞后现象。计算了吸附剂和吸附质的HOMO和LUMO轨道，认为芳香族吸附质和吸附剂的HOMO和LUMO能量差较小是吸附不可逆的原因。K2 CrO 4在水溶液中的AC单独和AC-芳族配体吸附剂上的吸附平衡，分别证明了由吸附的芳族化合物提供的碳表面的特定化学功能的有效发展。
The results presented in this work are related to the design of a guideline to develop specific properties at the surface of an activated carbon (AC). For this, two model aromatic compounds have been synthesized and their electrolytic behavior in aqueous solutions was studied by a potentiometric method. The textural characteristics of the activated carbon were determined by porosimetry methods. The nature of oxygen-carrying functions and the acid-base behavior of the AC surface were characterized by TPD and potentiometric titration methods, respectively. The adsorption and desorption equilibria of the aromatic compounds on activated carbon were measured in aqueous solutions, and the hysteresis between adsorption and desorption, which reveals irreversible adsorption, was discussed on the basis of the frontier orbital theory. HOMO and LUMO orbitals of the adsorbent and adsorbates were calculated, and irreversible adsorption was attributed to the small energy difference between HOMO and LUMO of the aromatic adsorbates and the adsorbent. Adsorption equilibria of K2CrO4 in aqueous solution on the AC alone and on the AC-aromatic ligand adsorbents, respectively, prove the efficient development of specific chemical functions at the carbon surface provided by the adsorbed aromatic compounds.