纳米二氧化钛在不同水溶液中的团聚及铅吸附效应比较

Comparative Study on Aggregation and Lead Adsorption Effect of Nano-TiO2 in Different Aqueous Solutions

目的研究并比较不同浓度纳米二氧化钛(titanium dioxide nanoparticles,nano-TiO2)在超纯水、DMEM培养基和水库水中的团聚效应及其对铅的吸附情况。方法用以超纯水、DMEM培养基和水库水为溶剂的1μg/ml乙酸铅溶液倍比稀释纳米二氧化钛溶液终浓度分别为0.001、0.01、0.1、1、10μg/ml。采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)检测分散状态和团聚状态纳米二氧化钛粒径,采用纳米粒度仪检测纳米二氧化钛在水溶液中团聚粒径,采用石墨炉原子吸收(GFAAS)法检测纳米二氧化钛对铅的吸附量。结果在分散状态下,纳米二氧化钛粒径约为20～30 nm。除在0.001μg/ml纳米二氧化钛和乙酸铅混合溶液中未检测到外,纳米二氧化钛与乙酸铅团聚体在纯水、DMEM培养基、水库水中的平均粒径分别为(297±16),(301±10),(302±19)nm。不同浓度纳米二氧化钛和乙酸铅混合溶液在同种水溶液中聚合物粒度大小无显著差异,相同浓度纳米二氧化钛和乙酸铅混合溶液在不同水溶液中团聚物体粒径大小亦无显著差异。纳米二氧化钛对铅的吸附量随纳米二氧化钛剂量升高呈现出剂量依赖性上升(均P<0.05)。但相同浓度不同水溶液中纳米二氧化钛对铅的吸附量没有显著性差异。结论在无分散剂的三种水溶液中,纳米二氧化钛迅速发生团聚,并能够吸附铅,团聚和吸附效应无差别。

Objective To observe the aggregation effect of nano-TiO2 and the PbAc adsorptive capacity of nano-TiO2 in different aqueous solution. Methods The dispersion and aggregation effect of nano-TiO2 were detected by SEM and TEM in this study. The aggregation size of nano-TiO2 in aqueous solution was detected by a Nano-Particle Analyzer. The adsorptive capacity of Pb2＋ onto nano-TiO2 was detected by graphite furnace atomic absorption spectrometry. Results The size of nano-TiO2 particle with dispersion state was about 20 nm observed by SEM and TEM. The average aggregation size was （297±16） nm in pure water, （301±10） nm in DMEM medium and（302±19）nm in reservoir water. The particle size of nano-TiO2 in different concentrations or in the same aqueous solution had no significant difference after aggregation （P〉0.05）. The adsorption quantity of Pb2＋ onto nano-TiO2 showed a dose-dependent manner with the increase of the concentrations of nano-TiO2 （P〈 0.05）. Conclusion Nano-TiO2 treated alone in the absence of surfactants can aggregate rapidly and can adsorb Pb2＋ in different aqueous solution, and no difference can be seen in aggregation and adsorption effects.