砷(Ⅲ)离子印迹聚合物的制备及吸附性能研究

Preparation and adsorption characteristics of arsenic (Ⅲ) ion-imprinted polymer

以磁性氧化石墨烯为载体,砷离子(As(Ⅲ))为模板离子,3-巯基丙基三甲氧基硅烷(MPTS)为功能单体,正硅酸乙酯(TEOS)为交联剂合成了As(Ⅲ)离子印迹磁性氧化石墨烯纳米材料(MGO-IIP),并使用扫描电子显微镜、傅里叶变换红外光谱(FTIR)、X-射线衍射仪(XRD)和振动样品磁强计对合成材料进行了表征.同时,考察了MGO-ⅡP对As(Ⅲ)的吸附特性.结果表明:318 K下MGO-ⅡP对As(Ⅲ)的最大吸附量为148.1 mg·g^-1,仅20 min即可达到吸附平衡,印迹因子为2.35;吸附过程服从Langmuir模型和准二级动力学模型,说明是自发的吸热过程;在其他干扰离子存在的情况下,MGO-ⅡP对As(Ⅲ)仍然具有良好的吸附效果,且能够重复使用4次,在含砷废水处理中具有应用价值.MGO-ⅡP材料对As(Ⅲ)的吸附机制为表面络合作用及物理吸附.

In this study,arsenic(Ⅲ)ion-imprinted magnetic graphene oxide composite(MGO-ⅡP)was prepared with MGO as the supporter,As(Ⅲ)ion as the template,(3-mercaptopropyl)trimethoxysilane(MPTS)as the functional monomer and tetraethylorthosilicate(TEOS)as the crosslinking agent.The MGO-IIP was characterized by using scanning electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction and vibrating sample magnetometer.The adsorption properties of MGO-IIP for As(Ⅲ)ion were investigated,and the results show that the maximum adsorption capacity was 148.1 mg·g^-1 at 298 K.The adsorption equilibrium could be achieved only within 20 minutes with the imprint factor of 2.35.Further,the adsorption was a spontaneous endothermic process,and followed the Langmuir isotherm model and the pseudo-second-order kinetic model.More importantly,the MGO-ⅡP still had an excellent adsorption efficiency for As(Ⅲ)in the presence of some interfering anions.In addition,the resultant MGO-ⅡP shows high stability and could be reused for 4 times.Therefore,the resultant MGO-ⅡP can be potentially used to purify the arsenic-containing wastewater.The adsorption mechanism of MGO-ⅡP for As(Ⅲ)ion was surface complexation and physical adsorption.