An overview of the methylene blue ISO test for assessing the activities of photocatalytic films
An overview of the methylene blue ISO test for assessing the activities of photocatalytic films
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DOI：
10.1016/j.apcatb.2012.01.019
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发表时间：
2012-11-30
影响因子：
22.1
通讯作者：
Mills, Andrew
中科院分区：
文献类型：
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作者：
Mills, Andrew
介绍了国际标准化组织发布的标准：10678：2010年的主要特点，即“通过降解亚甲基蓝来测定水介质中表面的光催化活性”。考虑了该标准的主要基本假设，即：(I)染料纯度，(Ii)吸附和pH，(Iii)光源，(Iv)搅拌和扩散，(V)反应机理和(Vi)动力学。确定了由这些假设引起的可能的错误来源，并建议对标准的协议进行更改。主要建议的改变是：(I)应使用已知和现场证实的高纯度(>；90%)的MB+源来组成标准测试溶液，该标准测试溶液应具有参考吸光度0.74，在665 nm处；(Ii)调节溶液应与标准测试溶液的浓度相同；(Iii)反应溶液的初始pH应在5.5-6.0的范围内；(Iv)应使用掺Eu的氟硼酸锶或硼酸盐荧光粉的BLBUVA灯；(V)如有可能，应大力和连续地搅拌反应溶液：(Vi)溶液高度应为最小推荐值2厘米，光反应器圆筒直径应为4.7厘米；(Vii)照射3小时后，应让反应溶液搅拌过夜，以确保没有发生染料光还原漂白。这些建议中的大多数应用应该会大大改善该标准目前报告的实验室内重复性(9.2%)和实验室间重复性(30.6%)的较差百分比误差。(C)2012爱思唯尔B.V.保留所有权利。
The main features are described of the ISO published standard: 10678:2010, namely the 'Determination of photocatalytic activity of surfaces in an aqueous medium by degradation of methylene blue'. The main underlying assumptions of the standard are considered, namely: (i) dye purity, (ii) adsorption and pH, (iii) light source, (iv) stirring and diffusion, (v) reaction mechanism and (vi) kinetics. Possible sources of errors arising form these assumptions are identified and changes to the standard's protocol suggested. The major suggested changes are: (i) a source of MB+ of known and proven on site high purity (>90%) should be used to make up the standard test solution, which should have a referenced absorbance, 0.74, at 665 nm; (ii) the conditioning solution should be the same concentration as the standard test solution, (iii) the initial pH of the reaction solution should lie in the range: 5.5-6.0; (iv) a BLB UVA light with a europium-doped strontium fluoroborate or borate phosphor should be used; (v) the reaction solution should be vigorously and continuously stirred if possible: (vi) the solution height should be the minimum recommended value of 2 cm, and the photoreactor cylinder id., 4.7 cm; (vii) after the 3 h irradiation the reaction solution should be left stirring overnight to check that no dye photoreductive bleaching has occurred. Application of most of these suggestions should improve considerably the standard's reported current poor percentage errors for repeatability within a lab (9.2%) and reproducibility between labs (30.6%). (C) 2012 Elsevier B.V. All rights reserved.