Study On Methods For Determination Of Titanium Dioxide In Water

Wet collecting for nano-TiO₂ in workshop air is a new sampling technology. It adopts aqueous solution as collection. Nano-TiO₂ can disperse in solution easily, and form a stable system. Determining contents of Nano-TiO₂ in collection aqueous solution is a problem that must be solved. Aqueous solution as collector is used to collect nano-TiO₂ in the producing workshop air, and the methods determining nano-TiO₂ contents in water are built, including: ultraviolet spectrometry, H₂O₂ spectrophotometry, the diantipyrine methane spectrophotometry. Then determining conditions are optimized and the three methods are compared.The determination of absorption by Ultraviolet spectrometry is performed at 330 run, after 50mL sample dispersing for 40min by 150Wx70% power and reposing for 4min. Under the best dispersing condition, the concentration of nano-TiO₂ is determined. Beer's law is obeyed in the concentration range of 1.0 mg/L～100 mg/L. The correlation coefficient is 0.9999. The relative error is less than 5.08% and the relative standard deviation is less than 1.31%.The conditions of the spectrophotometry with H₂O₂ as color reagent are optimized by orthogonal design. The experimental procedure is as follows: first, samples are dryed at the temperature of 150℃; second, samples are dispelled with 10mL dispeling liquid until the samples colour turning transparent; the last, absorption are determined at 410 nm, after adding 5mL color reagent and reposing for 40min. Beer's law is obeyed in the concentration range of 1.0 mg/L～60 mg/L. The correlation coefficient is 0.9991. The limit of detection is 0.00236 mg/L. The recovery efficient is 91.43%～106.1% and the relative standard deviation is less than 5.52%.The conditions of the spectrophotometry with the diantipyrine methane spectrophotometry as color reagent are optimized by orthogonal design. The experimental procedure is as follows: first, samples are dryed at the temperature of 150℃; second, samples are dispelled with 10mL dispeling liquid until the samples colour turning transparent; the last, absorption is determined at 390 nm, after adding 6mL color reagent, 10mL HCl(5+1) and reposing for 20min. The Linearity range of the experiment is 0.1mg/L～3.0mg/L. The correlation coefficient is 0.9990. The limit of detection is 0.00419mg/L. The recovery efficient is 99.6%～109.0% and the relative standard deviation is less than 6.34%.