SBA-15纳米介孔分子筛对Cr(Ⅲ)的吸附性能研究

Adsorption Performance of SBA-15 Nano Mesoporous Molecular Sieve for Cr(Ⅲ)

研究了采用水热合成法以三嵌段表面活性剂P123和正硅酸乙酯(TEOS)为原料制备SBA-15纳米介孔分子筛,借助X-射线衍射、扫描电镜、透射电镜等表征其结构。考察了溶液酸度、吸附剂用量、Cr(Ⅲ)质量浓度、接触时间、温度等对SBA-15吸附Cr(Ⅲ)的影响。结果表明:所制备的SBA-15为直径333±10nm的纤维状晶粒;在适宜条件下,SBA-15对Cr(Ⅲ)的吸附容量为12.17mg/g,吸附过程符合Freundlich等温模型,为异相吸附,并可用准二级动力学模型描述;在25~55℃范围内,吸附过程可自发进行,吸附过程中放热,ΔG^0<0,ΔH^0=-28.329kJ/mol,ΔS^0=-47.454J/(mol·K)。

Nano mesoporous molecular sieve SBA-15 was prepared by hydrothermal synthesis using tri-block surfactant P123 and tetraethyl orthosilicate as raw materials.By means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy,SBA-15 structure was characterized. The effects of solution acidity,adsorbent dosage,Cr(Ⅲ)mass concentration,contact time and temperature on adsorption of Cr(Ⅲ) were examined.The results show that SBA-15 is a fiber particle with a diameter of 333±10 nm.Under the suitable conditions,SBA-15 adsorption capacity for Cr(Ⅲ) is 12.17 mg/g.The adsorption process accords with Freundlich isotherm model and is heterogeneous adsorption.And the pseudo-second-order kinetic model can be used to describe this adsorption process.At the range of 25~55 ℃,the adsorption process can occur spontaneously with Δ G^0 <0,Δ H^0 =-28.329 kJ/mol,Δ S^0 =-47.454 J/(mol·K).