pH敏感型纳米粒子的制备及其对含油污水的净化

Preparation of pH-sensitive Nanoparticles and Their Purification of Oily Wastewater

摘要:

首先采用共同沉淀法制备Fe3O4磁性纳米粒子，再通过正硅酸四乙酯水解包覆在其表面形成SiO2壳层，最后将硅烷偶联剂KH-550在Fe3O4@SiO2上进行接枝改性，得到表面氨基功能化的磁性纳米粒子(A-MNPs)。通过TEM、FTIR、VSM对纳米粒子的微观形貌、化学组成、磁学性能进行了测试，并将其应用于油田含油污水的净化处理。结果显示：表面氨基化的结构使A-MNPs具有pH敏感性，因此可通过改变pH值实现A-MNPs的重复使用，当pH=4时A-MNPs达到最佳除油效果。当A-MNPs浓度为200 mg/L时便可将模拟含油污水透光度提高到99.4%； 500 mg/L的A-MNPs重复使用10次后仍可使净化后含油污水的透光度保持在80%以上；A-MNPs对由不同浓度的氯化钠、高岭土、乳化油、部分水解聚丙烯酰胺（HPAM）组成的多种模拟污水也有较好的净化效果，375 mg/L的 A-MNPs可使净化后复杂污水的透光度达到86.5%以上。

Abstract:

Fe3O4 magnetic nanoparticles were first prepared by chemical coprecipitation method, and then SiO2 was coated on Fe3O4 nanoparticles by hydrolyzation of tetraethyl orthosilicate. Subsequently, amino-functionalized magnetic nanoparticles (A-MNPs) were obtained by grafting KH-550 on the Fe3O4@SiO2. The microscopic morphology, chemical composition and magnetic properties of nanoparticles were tested by TEM, FTIR and VSM. Next, A-MNPs were applied to purify oily wastewater. It was found that surface amino-functionalization of A-MNPs can improve their pH-sensitivity, thus, the reuse of A-MNPs can be realized by changing pH value. When the pH value of solution was 4, A-MNPs exhibited the best oil removal effect. When the concentration of A-MNPs was 200 mg/L, the light transmittance of the simulated oily wastewater was 99.4%. However, when the concentration of A-MNPs was 500 mg/L, the transmittance could be kept above 80% even after 10 times of repeated use. In addition, A-MNPs had better purification effects for various simulated sewage composed of different concentrations of sodium chloride, kaolinite, emulsified oil and partially hydrolyzed polyacrylamide (HPAM). 375 mg/L A-MNPs could make the light transmittance of complex sewage reach more than 86.5% after purification.