一锅水热法制备全氟辛磺酸盐印迹碳微球及其吸附性能研究

Preparation of Molecularly Imprinted Carbon Microspheres by One-Pot Hydrothermal Method and Their Adsorption Properties to Perfluorooctane Sulfonate

采用废弃油茶籽壳生物质作为碳源,以全氟辛烷磺酸盐(PFOS)作为模板分子,间苯三酚为添加剂,通过一锅水热法制备了具有PFOS印迹的水热碳微球(PFOS-MIC)。采用扫描电镜(SEM)、透射电镜(TEM)、比表面积和孔径分布仪(BET)、傅里叶变换红外光谱仪(FT-IR)、热重/差热综合分析仪(TG/DTA)等对其进行了表征。PFOS印迹碳微球粒径约1.5 μm,内部由大量缔合氢键形成印迹位点。考察了此印迹碳微球对水中PFOS的吸附性能,如吸附动力学、pH值影响、吸附等温线及吸附选择性。结果表明,非印迹碳微球和印迹碳微球对PFOS的吸附动力学均符合拟二级动力学模型( R 2>0.994),在20℃,pH=3条件下,吸附平衡时间分别为1.5和3.0 h;酸性条件有利于PFOS的吸附;吸附等温线数据符合Langmuir吸附模型( R 2>0.993),20℃下最大吸附量分别为2930和5380 μg/g。选择性实验结果表明,在结构类似物共存的条件下,印迹碳微球对PFOS具有较好的吸附选择性。

Molecularly imprinted carbon microspheres (MIC) were synthesized by one-pot hydrothermal method with perfluorooctane sulfonate (PFOS) as template, camellia oleifera seed shell as carbon precursor and phloroglucinol as additive. The as-prepared PFOS-MIC was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area and pore size distribution analyzer (BET), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetry/differential thermal analyzer (TG/DTA). The results of SEM, HRTEM and FT-IR showed that the PFOS-MIC had a particle size of about 1.5 μm, the activated binding sites were formed by a large number of interconnected hydrogen bonds. The adsorption properties of PFOS on PFOS-MIC and the corresponding non-imprinted carbon microspheres (NIC) such as adsorption kinetics, pH effect and adsorption isotherms were investigated. Results showed that the adsorption kinetics of PFOS on both NIC and PFOS-MIC fitted well with the secondary-kinetic model ( R 2> 0.994 ). When the temperature was set at 20℃ and pH=3, the adsorption equilibrium time was 1.5 h and 3.0 h, respectively. The lower pH was positive to the adsorption. The adsorption isotherms data fitted better to the Langmuir model ( R 2>0.993) than that of Freundlich model, and the maximum adsorption capacity at 20℃ was 2930 and 5380 μg/g for NIC and PFOS-MIC, respectively. Adsorption selectivity results indicated that the PFOS-MIC had good adsorption selectivity for PFOS, even in coexistence with the structure analogue surfactants.