电子教案与课件：《化工专业英语》Unit15.ppt

1、Unit 15 Advanced Oxidation ProcessHang XuHenan University of Science and TechnologyThe most widely used advanced oxidation treatments for organic wastewater are commonly referred to as advanced oxidation processes(AOPs).最广泛使用的先进氧化处理技术通常称为高级氧化工艺（AOPs）。AOPs are generally defined as oxidation processes

2、 generating hydroxyl radicals(OH)which,in turn,are responsible for organic degradation due to their strong oxidant power.AOPs通常定义为产生羟基自由基的氧化过程，由于它们的强氧化剂能力（HO+H+e-H2O），可以进行有机降解。Most of the systems classified as AOPs make use of a combination of either(I)two oxidants(O3/H2O2),(II)a catalyst and an oxi

3、dant(Fe2+/H2O2),(III)an oxidant and irradiation(UV/O3,UV/H2O2)and(IV)irradiation and a catalyst(UV/TiO2)and so on.大多数高级氧化技术可以分为以下几种情况：（I）两种氧化剂（O 3/H 2 O 2）或（II）催化剂和氧化剂（Fe 2+/H2O2），（III）氧化剂和照射（UV/TiO 2），（V）照射，催化剂和氧化剂（UV/Fe 2+/H2O2）或（VI）氧化剂（H2O2）和超声波辐照。The common drawback of such systems is the high d

4、emand of electrical energy for devices such as ozonizers,UV lamps,etc.This makes such treatments economically disadvantageous.这种系统的共同缺点是诸如臭氧发生器、UV灯、超声波发生器等装置需要高电能，这使得这种处理在经济上是不利的。This is why,although AOPs are well known for their capacity for oxidizing and mineralizing almost any organic contaminant

5、,commercial applications are still scarce.这就是为什么尽管AOPs能氧化和矿化几乎任何有机污染物，但商业应用仍然很少的原因。Several promising cost-cutting approaches have been proposed based on a real integration of the AOPs as part of a whole treatment train or process.作为整个处理过程的一部分，已经提出了几种很有前途的降低成本的方法。Other proposed cost-cutting measures

6、are the use of renewable energy sources,i.e.sunlight as irradiation source for TiO2 photocatalysis and photo-Fenton,further advances and development of applied reactors have improved plant operation and control strategies to raise the degree of automation and lower the operational costs.其他提出的降低成本的措施

7、是使用可再生能源，即太阳光作为 TIO2光催化和光芬顿的辐照源，应用反应器的进一步发展和开发改进了工厂操作和控制策略，以提高自动化程度和降低操作成本。The solar approach is a logical consequence for AOPs cost saving to be applied especially in the Southern Europe regions.太阳能方法是 AOPS 节约成本的蕴涵，尤其适用于南欧地区。Solar advanced oxidation processes have high reaction rate constants for m

8、ost reactions involving hydroxyl radicals in aqueous solution.太阳能高级氧化过程对于大多数涉及水溶液中羟基自由基的反应都有很高的反应速率常数。They are also characterized by their nonselective attack,which is a useful attribute for wastewater treatment and solution of pollution problems.他们也拥有属性他们的非选择性攻击，这是一个有用的属性废水处理和污染问题的解决方案。The versatil

9、ity of AOPs is also enhanced by the fact that there are different ways of producing hydroxyl radicals,facilitating compliance with the specific treatment requirements.生成羟基自由基的不同方式也增强了AOPS 的多功能性，促进了对特定治疗要求的遵守。During an ideal treatment by solar AOPs,contaminants are structurally altered forming smalle

10、r and more biodegradable compounds until complete mineralization is achieved.在一个理想的处理过程中，太阳能光伏，污染物的结构改变形成更小和更可生物降解的化合物，直到完全矿化实现。For the application of AOPs in wastewater treatment,the objectives can be either to:(i)eliminate biorecalcitrant and toxic compounds,(ii)increase the biodegradability of wa

11、stewater before applying conventional biological process,(iii)reduce the level of toxicity and micropollutants in the effluent or(iv)disinfect the wastewater instead of applying traditional disinfection methods such as chlorination,which is known to generate carcinogenic and mutagenic by-products su

12、ch as halomethanes.对于 AOPS 在废水处理中的应用，目标可以是:(1)消除生物顽抗性和有毒化合物;(2)在应用常规生物工艺之前提高废水的可生物降解性;(3)降低废水中的毒性和微污染物水平;或(4)对废水进行消毒，而不是应用已知产生致癌和致突变副产物如卤甲烷等的传统消毒方法。Photocatalysis change in the rate of a chemical reaction or its initiation under the action of UV,visible or infrared radiation,and the photocatalysts t

13、hat absorb light quanta are involved in the chemical transformation of the reaction partners.在紫外光、可见光或红外线的作用下，化学反应速率或起始速率的光催化变化，以及吸收光量的光催化剂参与了反应伙伴的化学转化。Despite the existence of various photocatalysts,most studies involve TiO2 as semiconductor candidate despite its limitations,such as a low efficienc

14、y and a narrow light response factor due to its bandgap(3.2 eV).尽管有各种各样的光催化剂存在，但是大多数的研究都把二氧化钛作为半导体候选材料，尽管它存在一些局限性，例如由于它的禁带宽度(3.2 ev)而导致效率低和光响应因子窄。The most prevalent applications of TiO2 areas white pigments in paints,plastics,paper,fibers,foods,pharmaceuticals,and personal care products,mainly due t

15、o its light scattering properties and high refractive index.二氧化钛主要应用于油漆、塑料、纸张、纤维、食品、医药和个人护理产品，主要是因为它的光散射和高折射率。When TiO2 is excited with light,an electron is promoted from the valence band to the conduction band,generating a hole(h+)in the valence band and an electron(e-)in the conduction band.当TiO2被

16、光激发时，电子从价带跃迁到导带，产生价带中的空穴（H+）和导带中的电子（e-）。The photogenerated charge carriers can either migrate to the surface of the TiO2,where it can actively perform its role in the oxidation-reduction reactions with the pollutant or recombine in the bulk or on the TiO2 surface.光生电荷载体可以迁移到TiO2的表面，其中它可以主动地在污染物氧化还原反

17、应中发挥作用或者在本体或TiO2表面上重组。A generated photohole can react with an adsorbed water molecule or OH-anions to form powerful OH(Eq.1 and 2).产生的光生空穴与吸附的水分子或OH-阴离子反应形成强大的HO自由基（方程1和2）。When molecular oxygen is available,it is adsorbed onto the surface of TiO2 and can scavenge an electron to form the superoxide r

18、adical anion(Eq.3).当分子氧可用时，其被吸附到TiO2的表面上并且可以清除电子形成超氧自由基阴离子（Eq.3）。However,a limitation of solar photocatalysis is the poor overlap of the solar spectrum with the absorption spectrum of TiO2(5%).然而，太阳光催化的局限性是太阳光谱与TiO2吸收光谱的重叠不好（5）。TiO2 doping with non-metals,metal-ion implantation,co-doping and sensiti

19、zing TiO2 with dyes have been applied to address this limitation and to improve TiO2 photocatalytic efficiency.向TiO2中掺杂非金属，注入金属离子，共掺杂和用染料敏化TiO2，以解决这个局限并提高TiO2光催化效率。Doping results in a better absorption in the visible region as it induces a change in the optical response of TiO2 and produces higher p

20、hotonic yields.掺杂导致在可见光区域有更好的吸收，因为它诱导TiO2的光学响应的变化并产生较高的光子产率。In contrast,doping significantly increases the cost of the photocatalyst due to expensive ion implantation facilities.相比之下，由于昂贵的离子注入设备，显著增加了光催化剂的掺杂成本。Words and Expressionadvanced oxidation processes 高级氧化技术hydroxyl radicals 羟基自由基ozonizer zunaizr n.臭氧发生器nonselective attack 无选择进攻mineralization mnrlazen n.矿化作用biodegradability of wastewater 污水的生物降解性carcinogenic k:sndenk a.致癌物（质）的mutagenic mju:tdenk a.诱导有机体突变的物质light quanta 光量子dye da n.染料oxidation-reduction reaction 氧化还原反应