APTES改性羧甲基壳聚糖微球对铅离子吸附性能及机理研究

以羧甲基壳聚糖(CMCS)为基体,3-氨基丙基三乙氧基硅烷(APTES)作为改性剂,制备了用于吸附铅离子的改性羧甲基壳聚糖微球(A-CMCS)。使用扫描电子显微镜(SEM)、能谱仪(EDS)、傅里叶红外光谱仪(FT-IR)对吸附剂的表面形貌以及化学组成及结构进行了表征。研究了初始溶液的pH值、吸附温度以及铅离子的初始浓度对A-CMCS吸附性能的影响,结果表明当pH值为5、吸附温度为303 K时吸附剂对铅离子的吸附浓度达到最大为275.2 mg/g,比未改性之前的交联微球的吸附量提升43%。并使用吸附动力学以及等温吸附模型、FT-IR和X射线光电子能谱(XPS)对吸附机理进行了探究,其结果发现A-CMCS微球对铅离子的吸附过程是一个以化学吸附为主的单分子层吸附过程,其中氨基基团在整个吸附过程的起主导作用。

Adsorption properties and mechanism of APTES modified carboxymethyl chitosan microspheres for lead ion

APTES modified carboxymethyl chitosan microspheres(A-CMCS) for adsorption of lead ions were prepared by 3-aminopropyltriethoxysilane(APTES). The surface morphology, chemical composition and structure of the adsorbent were characterized by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and Fourier transform infrared spectroscopy(FT-IR). The effects of initial solution pH, adsorption temperature and initial concentration of lead ions on the adsorption performance of A-CMCS were studied. The results showed that when the pH was 5 and the adsorption temperature was 303 K, the adsorption concentration of the adsorbent on lead ions reached 275.2 mg/g, and the adsorption amount of the crosslinked microspheres before unmodified was increased by 43%. The adsorption mechanism was studied by adsorption kinetics and isothermal adsorption model, FT-IR and X-ray photoelectron spectroscopy(XPS). The results showed that the adsorption process of lead ions by A-CMCS microspheres was a chemical adsorption-based single molecular layer adsorption process, in which the amino group played a leading role in the entire adsorption process.