海藻酸钙-二氧化硅杂化材料的制备及对Cu(Ⅱ)吸附性能

Preparation of Calcium Alginate-SiO2 Hybrid Materials and Adsorption Properties for Cu(Ⅱ)

利用海藻酸钠(SA)、正硅酸四乙酯(TEOS)为原料,通过反应制备海藻酸钙/二氧化硅(CA/SiO2)杂化材料,利用傅里叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)对材料的结构以及表面、断面进行表征,采用原子力发射光谱仪测试杂化材料作为吸附剂对Cu2+吸附性能,并从吸附动力学和热力学角度分析吸附机理。结果表明,红外光谱证实杂化材料制备成功;扫描电子显微镜观察到杂化材料表面趋于平整,断面结构看到材料的内部孔洞较多。吸附实验结果表明,杂化材料对Cu2+去除率较CA提升67.01%,最佳吸附条件为温度为55℃、pH处于中性条件;同时吸附过程符合拟一阶动力学模型及Freundlich等温吸附模型,Langmuir模型计算得到对Cu2+最大吸附容量为129.6 mg/g,Freundlich常数0<1/n=0.4672<0.5,吸附过程容易进行;并且材料具备多离子同时吸附能力,重复使用5次仍有优异去除率。

A calcium alginate/silica(CA/SiO2) hybrid adsorbent was prepared using sodium alginate(SA) and tetraethyl orthosilicate(TEOS) as raw material. The structure, surface and section of the material were characterized by FT-IR and SEM. The adsorption performance of Cu2+ as adsorbent was tested by atomic force emission spectrometer, and the adsorption mechanism was analyzed through the viewpoint of adsorption kinetics and thermodynamics. The results show that the hybrid material was successfully prepared from FT-IR;SEM show that the surface of the hybrid material tends to be flat, and the cross-sectional structure shows more internal pores of the material. The results of adsorption experiments show that the removal rate of Cu2+ by CA/SiO2 is 67.01% higher than that of CA, and the optimal adsorption conditions are t=55 ℃ and pH=6~7;it is consistent with the quase first-order kinetic model and the Freundlich isotherm adsorption model. According to the Langmuir model, the maximum adsorption capacity of Cu2+ is 129.6 mg/g, and the Freundlich constant is 0<1/n=0.4672<0.5, the adsorption process is easy to occur. CA/SiO2 has the ability to simultaneously adsorb multiple ions, and the removal rate is excellent after repeated use for 5 times.