Amino Acid Adsorption on Mesoporous Materials: Influence of Types of Amino Acids, Modification of Mesoporous Materials, and Solution Conditions

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• 作者：Qiang Gao ; Wujun Xu ; Yao Xu ; Dong Wu ; Yuhan Sun ; Feng Deng ; Wanling Shen
• 刊名：Journal of Physical Chemistry B
• 出版年：2008
• 出版时间：February 21, 2008
• 年：2008
• 卷：112
• 期：7
• 页码：2261 - 2267
• 全文大小：137K
• 年卷期：v.112,no.7(February 21, 2008)
• ISSN：1520-5207

文摘

In order to disclose the dominant interfacial interaction between amino acids and ordered mesoporous materials,the adsorption behaviors of five amino acids on four mesoporous materials were investigated in aqueoussolutions with adjustable amino acid concentration, ion strength, and pH. The selected amino acids wereacidic amino acid glutamic acid (Glu), basic amino acid arginine (Arg), and neutral amino acids phenylalanine(Phe), leucine (Leu), and alanine (Ala), and the selected mesoporous materials were SBA-15, Al-SBA-15,CH₃(10%)-SBA-15, and CH₃(20%)-SBA-15. The adsorption capacities of Glu and Arg were stronglydependent on pH and surface charge of the mesoporous adsorbent. The adsorption of Phe showed pHinsensitivity but depended on the surface organic functionalization of mesoporous adsorbent. On the basis ofthe theoretical analysis about the interaction between amino acid and adsorbent, such a remarkable differencewas attributed to the different nature of the interaction between amino acid and adsorbent. Arg could bereadily adsorbed on the surface of SBA-15, especially Al-SBA-15, under appropriate pH in which theelectrostatic interaction was predominant. The driving force of Phe adsorption on mesoporous adsorbent mainlycame from the hydrophobic interaction. Therefore, the adsorption capability of Arg decreased with increasingion strength of solution, while the adsorption capability of Phe increased with the increasing degree of CH₃functionalization on SBA-15. For neutral amino acid Phe, Ala, and Leu, the adsorption capability increasedwith the increase of the length of their side chains, which was another evidence of hydrophobic effect. Thus,all the adsorption of amino acids on mesoporous silica materials can be decided by the combined influenceof two fundamental interactions: electrostatic attraction and hydrophobic effect.