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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 study and compare the agglomeration effect of titanium dioxide nanoparticles (nano-TiO2) in ultrapure water, DMEM medium and reservoir water and its adsorption on lead. Methods The final concentrations of nano-titania solution diluted 1μg / ml in lead acetate solution with ultrapure water, DMEM medium and reservoir water as solvent were 0.001, 0.01, 0.1, 1 and 10μg / ml, respectively. The particle size of nano-TiO2 was measured by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The size of agglomeration of nano-TiO2 in aqueous solution was determined by nano-particle size analyzer. The particle size was determined by graphite furnace atomic absorption spectrometry Titanium dioxide adsorption of lead. Results In the dispersed state, the size of nano-titanium dioxide is about 20 ~ 30 nm. Except 0.001μg / ml nano-titania and lead acetate mixed solution, the average diameters of nano-titania and lead acetate aggregate in pure water, DMEM medium and reservoir water were (297 ± 16) and ± 10), (302 ± 19) nm. There was no significant difference in the size of polymer between nano-titania and lead acetate solutions in the same aqueous solution. There was no significant difference in the particle size of agglomerated nano-titania and lead acetate solutions in different aqueous solutions with the same concentration. The adsorption amount of lead by nano-titanium dioxide showed a dose-dependent increase with the increase of nano-titanium dioxide dose (all P <0.05). But the same concentration of different aqueous solution of titanium dioxide adsorption of lead no significant difference. Conclusion In the three dispersants-free aqueous solution, nano titanium dioxide agglomerate rapidly, and can lead adsorption, agglomeration and adsorption no difference.