Abstract:

A novel functionalized SBA-15 material (N-SBA-15) was synthesized via Schiff's base reaction of 2-pyridinecarboxaldehyde with amino modified SBA-15 mesoporous material for adsorption of Cr(Ⅲ) ions from aqueous solution. The organic functional groups, morphology, pore structure and chemical property of N-SBA-15 were determined by FTIR, XRD, EDX, SEM, TEM, XPS, TGA and N₂ adsorption-desorption. Moreover, the adsorption performance of N-SBA-15 adsorbent on Cr(Ⅲ) ions in aqueous solution was investigated. The adsorption capacity of 84.3mg/g toward Cr(Ⅲ) ions was obtained. The kinetics analysis and adsorption isotherms revealed that the adsorption process of Cr(Ⅲ) ions by N-SBA-15 was consistent with pseudo-second-order kinetic model and Langmuir isotherm model. The thermodynamic parameters showed that Cr(Ⅲ) adsorption onto N-SBA-15 was spontaneous, endothermic and entropy-increasing process (?G<0, ?S>0, ?H>0). The adsorption mechanism analysis indicated that Cr(Ⅲ) adsorption onto N-SBA-15 was mainly based on the chemical combination of N atoms on the organic functional groups of N-SBA-15 through coordination bond. Furthermore, N-SBA-15 still kept high adsorption capacity after five adsorption–desorption cycles.

Key words: SBA-15, 2-pyridinecarboxaldehyde, Schiff's base, adsorption, Cr(Ⅲ)

摘要：

通过席夫碱反应将2-吡啶甲醛成功嫁接到氨基化的SBA-15介孔分子筛上，本文获得了一种新型功能化SBA-15吸附剂（N-SBA-15）。采用傅里叶变换红外光谱、X射线衍射、元素分析、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、热重分析和氮气吸附-脱附等手段对N-SBA-15的表面官能团、形貌、孔道结构和表面化学性质进行了详细的表征分析。利用N-SBA-15对水溶液中的Cr(Ⅲ)进行了吸附实验，其最大吸附容量为84.3mg/g。动力学分析和等温吸附研究结果表明，N-SBA-15对Cr(Ⅲ)的吸附过程符合准二级动力学模型和Langmuir模型。吸附热力学分析表明，该吸附过程是自发的吸热过程（?G<0、?S>0、?H>0）。吸附机理分析表明该吸附过程主要是由N-SBA-15表面有机官能团与Cr(Ⅲ)的配位作用实现的。而且，N-SBA-15吸附剂经过5次吸附-脱附测试，仍然对Cr(Ⅲ)具有较高的吸附容量。

关键词: SBA-15, 2-吡啶甲醛, 席夫碱, 吸附, Cr (Ⅲ)