单波长、双波长、三波长分光光度法测量TiO_2悬浮体系中亚甲基蓝浓度的表征

纳米颗粒态TiO2在实际运用中往往会形成TiO2悬浮颗粒和溶解态物质共存的混合液。对于混合液中溶解物系,以亚甲基蓝为被测物,首次系统考察了单波长、两波长、三波长三种分光光度法在亚甲基蓝浓度为2.00 mg/l和TiO2浑浊度分别为0.11、0.14、0.17、0.21、0.27、0.31、0.34、0.37、0.41、0.51、0.53,TiO2浑浊度为0.34和亚甲基蓝浓度分别为1.00、1.25、1.50、1.75、2.00、2.25、2.50 mg/l两种情况下的测定结果的相对误差和标准差。结果表明,分光光度法测定结果的相对误差和标准差都会有不同程度的波动,这与TiO2对光的改变效应和亚甲基蓝聚合体效应是有关的,而单波长分光光度法的准确度和重现性较好,特别是在浑浊度不变的情况下。其中,导致吸光度产生急剧偏差的"综合效应"被首次提出。

Determination of Methylene Blue by Single-wavelength,Dual-wavelengths,Three-wavelengths Spectrophotometry in Titanium Dioxide Suspension System

The photocatalytic degradation of dye wastewater by aqueous suspension of nano-sized TiO2 can produce mixture with nano-sized TiO2.To determining the concentrations of methylene blue in the mixture by methods of single-wavelength or dual-wavelengths or three-wavelengths,the relative errors and standard errors of determination were firstly studied in the different turbidity of TiO2（0.11,0.14,0.17,0.21,0.27,0.31,0.34,0.37,0.41,0.51,0.53）and different concentration of methylene blue（1.00,1.25,1.50,1.75,2.00,2.25,2.50 mg/l）.The results show that the relative errors and standard errors fluctuate in different amplitude,which is related to the effect of light change caused by TiO2 and agglomeration of methylene blue.The method of single-wavelength show better performance in relative errors and standard errors,especially in stable turbidity mixture,in which comprehensive effect is firstly put forward.