【作者】 张继东；

【导师】 金利通；

【作者基本信息】 华东师范大学 ， 分析化学， 2004， 硕士

【摘要】 近年来，由于森林破坏、环境污染，二氧化碳的排放量剧增，全球气候变暖，臭氧层严重破坏，到达地面的紫外线的强度日益增加，导致各种日光性皮肤病患者人数显著增长。此外，自然界的很多现象也和紫外线的照射密切相关：塑料、合成树脂、橡胶和有机玻璃中高分子链的断裂降解；材料的老化；油漆涂料的粉化、开裂，甚至脱落；纸张的变黄、变脆等。1995年3月，在伦敦召开了紫外线防护国际研讨会，表明在世界范围内紫外线的防护已经引起人们的广泛重视。 纳米二氧化钛、氧化锌等多种纳米氧化物具有良好的紫外线屏蔽能力，与传统的有机紫外吸收剂相比，具有无毒、无味、热稳定好、不分解、不挥发、容易着色等优点，为此逐渐替代了有机紫外吸收剂得到了广泛的应用。对于纳米氧化物材料紫外屏蔽性能的评估方面，至今还没有完备的分析测试方法以及统一的评价标准。纳米行业的发展和经济建设的需求，都要求我们建立一套切实可行的评价方法与评估标准，开发简便的评估仪器，用于纳米氧化物紫外屏蔽性能的评定。 本论文以纳米氧化物紫外屏蔽分析仪的研制与开发为重点，从纳米氧化物紫外屏蔽的原理出发，提出了紫外分光光度的评价方法，制定了相应的评价标准，在此基础上研制开发了纳米氧化物紫外屏蔽分析仪，并进行了相关理论和实际应用的研究。论文共分五章： 第一章 绪论 本章从纳米材料、纳米氧化物的结构与特性、紫外屏蔽剂的屏蔽原理及其分类、纳米氧化物紫外屏蔽的研究进展四个方面对该领域的发展做了较为全面的概述。中文摘要第二章纳米氧化物紫外屏蔽性能评估方法的研究 以往的紫外屏蔽性能的评估方法有SPF法和紫外吸光光度法。但是这些方法都是建立在有机紫外吸收剂紫外屏蔽性能的评估基础之上，而对纳米氧化物紫外屏蔽性能却一直没有统一的评价方法。我们从纳米氧化物紫外屏蔽的机理出发，研究了紫外分光光度法用于纳米氧化物粉体紫外屏蔽性能评价的可能性，建立了一套简单实用的纳米氧化物紫外屏蔽方法。实验中对不同的分散剂进行了筛选，考察了纳米氧化物粉体在不同分散剂中的稳定性，对实验条件进行了优化。将该方法用于实际样品的分析，取得了令人满意的效果。第三章纳米氧化物紫外屏蔽分析仪的研制 目前，紫外屏蔽性能的评估仪器多数为国外厂家制造，国内还十分缺乏同类仪器。本章在前一章建立了纳米氧化物紫外屏蔽性能评估方法的基础上，研制开发了纳米氧化物紫外屏蔽分析仪，并制定了相应的评估标准，填补了国内该领域的空白。该仪器具有分析时间短，操作简便，数据重现性和精密度高，方法可靠等优点，市场前景广阔。第四章纳米二氧化钦薄膜电极的制备及其在纳米氧化物紫外屏蔽性能评估中 的应用 溶胶凝胶法制备了纳米TIOZ薄膜电极，AFM和XRD表征的结果说明该电极的纳米TIOZ为锐钦矿型。以纳米TIOZ薄膜电极为工作电极考察了该电极对紫外光的响应，发现200一380nm的紫外光可以激发该电极TIO:的价带电子，产生光电流。在该体系的溶液中，加入纳米氧化物粉体，由于不同的纳米氧化物对紫外光的屏蔽作用不同，因此纳米TIOZ薄膜电极上所产生的光电流也不同。由此出发，我们利用纳米Tio:薄膜电极上产生的光电流的大小评价了不同纳米氧化物材料的紫外屏蔽性能。在对实际样品进行分析时，该方法与紫外分光光度法所得的结果完全一致，说明这是一种完全可行的全新的评估方法。华东师范大学申请硕士学位论文中文摘要第五章纳米二氧化钦薄膜电极在化学需氧量测定中的应用 本章将溶胶一凝胶法制备的纳米TIO:薄膜电极用于化学需氧量(COD)的测定。实验中，以葡萄糖为响应底物，考察了纳米TIOZ薄膜电极的光催化行为，结果发现该电极的光电流信号对溶液COD值在0.5一235m留L范围内具有很好的线性响应，相关系数为0.9998。利用该电极测定废水样品的COD值，其结果与传统的重铬酸钾法能够较好地吻合。而与之相比，该方法具有测试速度快，不需有毒、昂贵试剂，便于实现自动化等优点，具有广阔的应用前景。华东师范大学申请硕士学位论文更多还原

【Abstract】 As the thickness of the ozone layer has decreased during recent decades, people are likely to be exposed to an increasing dose of ultraviolet radiation. This has been correlated with a higher risk of damage to the human body such as premature aging of skin, skin cancer and cataract. Excessive exposure to ultraviolet rays in sunlight can also induce coloring and deterioration in paper, paint, synthetic resins, and so on. The Ultraviolet Protection Conference held in London at 1995 showed that great attention has been paid to shielding from UV irradiation.Nano-oxides, such as titanium dioxide and zinc oxide, have characteristics making them ideal for use as broad-spectrum physical sunscreens in personal-care products. They are relatively transparent to visible light, but almost opaque to ultraviolet radiation. Compared to chemical sunscreens, nano-oxides have many advantages, such as none-toxcity, insipidity, chemical and thermally stability. As a good alternative to chemical sunscreens, nano-oxides have been widely used in many fields.However, there is no uniform detection method and standard to assess UV-shielding capabilities of nano-oxides now. The goal of our work in this paper was to set up an assessing method and to develop a relative instrument for the evaluation of UV-shielding capacities of nano-oxides.Chapter one: Critical reviewsA critical review of present development in related fields was presented in this part: the summary of nano-materials, structure and characteristics of nano-oxides, mechanism of UV-shielding, and process in the study of UV-shielding characteristicsof nano-oxides.Chapter two: Studies on the assessing method of UV-shielding capacity of nano-oxidesSPF and ultraviolet spectrophotometry are two widely used methods in monitoring the UV-shielding capacity of chemical sunscreens, but they cannot be directly used to evaluate the characteristics of nano-oxides, for the dispersity of nano-oxides is different from that of organic sunscreens. In this part, a simple assessing method was introduced which was based on ultraviolet spectrophotometry, and the experiment conditions were optimized. It showed good results when used to evaluate the UV-shielding capacity of real samples.Chapter three: Development of the assessing instrument for UV-shielding capacity of nano-oxidesFor the moment, most assessing instruments for UV-shielding are made by foreign factories, which are very expensive. But in our country there are no succedaneous products. Based on the work in Chapter Two, we succeeded in developing an instrument specialized at assessing the UV-shielding capacity of nano-oxides. This instrument possesses many advantages, such as short analysis time, simplicity, good reproducity and high precision, which supplies a gap in this field and has great market potential.Chapter four: Preparation of nano titanium dioxide film electrode and its application in UV-shielding Capacity assessment of nano-oxidesA nano titanium dioxide film electrode was prepared by sol-gel method and applied for assessing the UV-shielding capacity of nano-oxides. The results characterized by AFM and XRD showed that the titanium dioxide electrode was anatase, which could generate photocurrent when illuminated by ultraviolet radiation of 200-3 80nm. The photocurrent decreased differently as different nano-oxides were added in the system. For this reason, we used photocurrents to evaluate UV-shieldingcapacity of nano-oxides, and got the same results with ultraviolet spectrophotometry. Therefore, it is a new and feasible method for the UV-shielding capacity evaluation of nano-oxides though further researches should be done.Chapter five: Application of nano titanium dioxide film electrode in COD detectionIn this work, the nano titanium dioxide film electrode was used for chemical oxygen demand (COD) determination based on the charge transfer on the interface of TiOa film electrode and the passing solution. The photoelectric behavior of the TiO2 film electrode was studied, and the results showed t更多还原