Fe~(3+)改性纳米TiO_2薄膜的制备及其光催化性能

以溶胶凝胶法在釉面炻器上负载了经Fe3 改性的TiO2薄膜,用扫描电子显微镜、x射线衍射仪和紫外-可见漫反射光谱仪对其进行了表征和分析,并以苯酚为模型污染物,对其光催化活性和寿命进行了考察.结果表明,Fe3 -TiO2薄膜在釉面炻器表面分布均匀,厚度约为300nm,颗粒大小在纳米级;Fe3 的引入不仅抑制了TiO2颗粒的长大,同时也抑制了TiO2从锐钛矿向金红石的相变;掺杂Fe3 后,TiO2薄膜对紫外光的吸收明显增强,对可见光的吸收也有所增强并在465nm附近产生了吸收峰,随着掺杂量的增大则两种吸收均略有增强,且对紫外光的吸收发生了明显的红移;Fe3 的最佳掺杂量为0.03%,此时其光催化降解苯酚的反应速率常数是纯TiO2薄膜的1.46倍;重复使用10次后,Fe3 -TiO2薄膜没有发生光腐蚀,且催化活性仅降低了约6.3%.     

雾封层型氮掺杂二氧化钛尾气降解性能研究

将纳米TiO_2掺加于雾封层中喷涂在道路表面,不仅可用于道路预防性养护,还可降解汽车尾气,具有重要的应用价值。选择氮掺杂二氧化钛与50 nm锐钛矿二氧化钛,应用方式采用水溶液型和雾封层型,基于室外尾气降解试验与车轮磨耗试验,研究两种纳米TiO_2对NO_X与CO的降解效能并进行降解耐久性分析。结果表明:相较普通纳米TiO_2,雾封层型氮掺杂二氧化钛对NO_X与CO降解效能分别提高44. 8%和38. 8%;车轮磨耗试验后,雾封层型对NO_X与CO降解效能比水溶液型高4. 0%和3. 7%,说明雾封层型氮掺杂二氧化钛的降解效能优良且降解耐久性较好。     

掺Fe^3＋纳米TiO2薄膜的制备及光催化性能研究

采用溶胶凝胶法制备纳米TiO2薄膜过程中加入Fe^3＋，可以提高二氧化钛的光催化活性，Fe^3＋的最佳掺杂浓度在0．10％左右。     

TiO_2/PP填料光催化氧化预处理微污染湖泊水

将TiO2负载于聚丙烯(PP)填料而制成TiO2/PP复合填料,将其用于光催化氧化预处理微污染湖泊水。在进水流量为10 L/h、填料填充比为0.4、紫外灯辐照功率为30 W、原水pH值为7.35的条件下,连续运行3 h后,对CODMn、UV254、NH3-N、TP和叶绿素a的平均去除率分别为18.77%、16.44%、11.94%、20.27%和38.74%,达到了预处理的目的。     

多孔羟基磷灰石负载掺杂Fe~(3+)二氧化钛薄膜的光催化性能研究

通过将多孔羟基磷灰石(HAP)浸渍于掺杂Fe3+二氧化钛溶胶中再经干燥、烧结,制备出负载光催化剂。采用TEM、FT-IR和XRD对负载情况和物相进行了表征,此外重点讨论了不同的Fe3+掺杂量、煅烧温度和光照条件因素对光催化性能的影响。研究发现Fe3+的掺杂量对光催化性能有较大影响,当掺杂量为0.5%时对甲基橙有最大降解率为43.6%;煅烧温度对于光催化性能的影响更大,在600℃时由于锐钛矿和金红石共存而产生的混晶效应有利于催化性能的提高;此外研究还发现在卤钨灯下可获得最大降解率。     

纳米二氧化钛控制透水砖堵塞试验研究

为了研究纳米二氧化钛对陶瓷透水砖堵塞的控制效果,采用不同方式在透水砖表面负载纳米二氧化钛,并开展了一系列透水砖堵塞控制试验,测定了透水砖的透水系数随过水时间的变化。结果表明,引入适量纳米二氧化钛可以提高陶瓷透水砖的透水性能。在1 g和4 g纳米二氧化钛负载量下,采用喷涂法和浸提法负载1 g纳米二氧化钛的透水砖均表现出良好的透水性能。喷涂法负载纳米二氧化钛透水砖的透水性能优于浸提法,初期和末期透水系数比未负载纳米二氧化钛的透水砖分别高146.15%和100%。用喷涂法负载粒径为5～10、25、40、100 nm的纳米二氧化钛时,5～10 nm的透水砖表现出最佳的透水性能,且成本最低。因此,推荐采用喷涂法负载纳米二氧化钛,且最适粒径范围为5～10 nm。     

热致相分离法制备丙烯腈-丙烯酸甲酯/纳米TiO_2复合膜及膜性能研究

以自制的可熔融丙烯腈(AN)-丙烯酸甲酯(MA)共聚物为基体,以碳酸乙烯酯(EC)与柠檬酸三乙酯(TEC)为复配稀释剂,采用热致相分离法(TIPS)制备丙烯腈-丙烯酸甲酯(AN-MA)/纳米二氧化钛(TiO2)复合膜。借助场发射扫描电子显微镜(FESEM)、X-射线衍射仪(XRD)和万能试验机,从微孔膜的力学性能、水通量、孔隙率、晶型等方面对膜的结构与性能进行表征。结果表明,添加TiO2纳米粒子可以显著提高AN-MA微孔膜的机械强度和水通量。随着TiO2含量的增加,微孔膜的机械强度先增加后降低,TiO2质量分数为0.1%时,断裂强度最高可达8.0 MPa,比未添加TiO2的样品高36%。纳米TiO2的加入一定程度上抑制了大孔的产生,微孔膜结构更加均一。随着凝固浴温度的升高,微孔膜的力学性能逐渐提高,通量出现下降趋势。     

陶砂载Fe2O3-TiO2的制备及光催化性能研究

采用溶胶-凝胶法制备的陶砂载Fe2O3-TiO2改性催化材料,提高陶砂载TiO2催化活性降解有机物,并解决粉体TiO2易产生二次污染的问题。采用扫描电子显微镜,X射线衍射研究了陶砂载Fe2O3-TiO2催化材料的表面结构,用降解水中罗丹明-B的效率来评价了陶砂载Fe2O3-TiO2催化材料降解有机物的效果。     

三维电极生物膜反应器低温启动试验研究

采用人工配制硝酸盐氮废水,对三维电极生物膜反应器进行了低温(10～15℃)条件下的启动研究。挂膜过程在HRT为7 h、进水C/N值为2、连续流的条件下,采用0→20 mA→40mA→60 mA梯度电流驯化方式进行。分析了挂膜过程中氮素的转化,以及微电流作用对反硝化脱氮过程中碳源消耗量和出水pH值的影响,并观察了填料表面生物膜的微生物形态特征。结果表明,经过一个月的驯化挂膜,反应器对硝酸盐氮和总氮的去除率分别可稳定在90%和65%左右;微电流的电化学作用能够有效地缓冲反硝化脱氮系统的pH值,并可增强自养反硝化作用;挂膜完成后,填料生物膜上生长了大量1～2μm的短杆状反硝化菌。     

负载型纳米铁化学反硝化法去除硝酸盐氮的研究

采用液相还原法制备了以石墨为载体的负载型纳米铁，并以其为还原剂进行化学反硝化，考察了此种材料还原硝酸盐氮的特性。结果表明，负载型纳米铁在中性条件下能够快速将硝酸盐氮还原而去除；铁量相同而不同铁碳比的负载型纳米铁还原硝酸盐氮的速率有所不同；体系初始pH值越低则负载型纳米铁还原硝酸盐氮的速率越快，pH值为2时可在15min内将浓度为80mg／L的硝酸盐氮全部去除；体系中的溶解氧会与NO3^-争夺电子，在pH值较低时NO3^-的还原受溶解氧的影响较大；负载型纳米铁可构成微小原电池，在化学反硝化反应中Fe起主要作用，Fe^2＋对反应有促进作用。     

可见光响应型TiO2薄膜的制备及其应用

自从1972年Fujishima等发现受辐射的TiO2表面能发生水的持续氧化还原反应以来,TiO2光催化材料已得到广泛的研究。TiO2薄膜的制备方法很多,主要有液相制备方法、物理气相沉积法、化学气相沉积法、电化学方法等。采用不同的工艺方法或工艺参数制备的二氧化钛成分、结构、取向、厚度和用途均有所差异。本文主要论述了有关可见光响应型TiO2薄膜的制备方法、相应性质及其应用前景。     

Photocatalytic degradation of the cyanotoxin cylindrospermopsin, using titanium dioxide and UV irradiation

Cylindrospermopsis raciborskii produces the cyanotoxin cylindrospermopsin, which is commonly found in SouthEast Queensland water reservoirs, and has been responsible for the closure of these reservoirs as a source of drinking water in recent times. Thus, alternative more effective treatment methods need to be investigated for the removal of toxins such as cylindrospermopsin. This study examined the effectiveness of two brands of titanium dioxide under UV photolysis for the degradation of cylindrospermopsin. Results indicate that titanium dioxide is an efficient photocatalyst for cylindrospermopsin degradation. The titanium dioxide (TiO2), brand Degussa P-25 was found to be more efficient than the alternate brand Hombikat UV-100. There was an influence from solution pH (4, 7, and 9) with both brands of titanium dioxide, with high pH resulting in the best degradation rate. Importantly, there was no adsorption of cylindrospermopsin to titanium dioxide particles as seen with other cyanotoxins, which would adversely influence the degradation rate. Degradation rates were not influenced by temperature (19-34 degrees C) when P-25 was the source of TiO2, some temperature influence was observed with UV-100. Dissolved organic carbon concentration will reduce the efficiency of titanium dioxide for cylindrospermopsin degradation, however the presence of other inorganic matter in natural waters greatly assists the photocatalytic process. With minimal potentially toxic by-product formation expected with this treatment, and the effective degradation of cylindrospermopsin, titanium dioxide UV photolysis is a promising speculative alternative water treatment method.     

二氧化钛薄膜光催化性能及改性的研究进展

如何利用二氧化钛薄膜吸收太阳能降解有机污染物是国内外热门研究领域之一。本文针对此领域存在的问题,从二氧化钛的光催化作用原理出发,对影响二氧化钛薄膜的光催化性能的因素进行了详细的归纳总结。此研究为利用无污染方法降解有机物、保护环境和对生态环境的可持续发展的探究具有一定的推动意义。     

Oxidation of metal-diethylenetriaminepentaacetate (DTPA)--complexes during drinking water ozonation

This study investigates the oxidative transformation of diethylenetriaminepentaacetate (DTPA), a synthetic ligand, during drinking water ozonation. The rate coefficients for the reactions of CaDTPA3- and ZnDTPA3- with ozone were determined to be 6200 and 3500 +/- 150 M-1 s-1, respectively. The reactivity of Fe(III)DTPA2- towards ozone was found to be much lower (< 10 M-1 s-1), but near neutral pH the reactivity of the Fe(III)-complexes is dominated by [Fe(III)(OH)]DTPA3-. For the reaction of Fe[(III)(OH)]DTPA3- with ozone a rate coefficient of 2.4 +/- 0.2 x 10(5) M-1 s-1 was measured. The rate coefficients of the reactions of the ZnDTPA- and Fe(III)DTPA with OH radicals have been determined by a competitive method as 2.4 +/- 0.4 x 10(9) and 1.5 +/- 0.1 x 10(9) M-1 s-1, respectively at pH = 7. The degradation of low concentrations of DTPA complexes during ozonation was investigated in natural waters under drinking water relevant conditions. Based on our findings CaDTPA3- and ZnDTPA3- are judged as easily degradable. Fe(III)DTPA complexes showed a somewhat lower reactivity, but were still typically degraded by one order of magnitude at ozone dosages of approximately 20 microM (1 mg L-1) in the three natural waters tested. Molecular ozone was found to be the major oxidant for the metal-DTPA complexes during ozonation.     

Arsenic remobilization in water treatment adsorbents under reducing conditions: Part I. Incubation study

The redox transformation and mobility of arsenic in spent adsorbents under reducing conditions were studied using an incubation test with mixed reducing bacteria, high-performance liquid chromatography-atomic fluorescence spectrometry for speciation of soluble arsenic (As), and thermodynamic calculations. The spent adsorptive media, including granular ferric hydroxide, granular ferric oxide, titanium dioxide, activated alumina and modified activated alumina, were collected from pilot-scale filters that were tested for removal of arsenate [As(V)] from groundwater in New Jersey, USA. During 65 days of incubation of the spent adsorbents with nutrient media in closed containers, the electron activity, pe, was reduced from about 1.7 to -7. Meanwhile, reduction of Fe(III) to Fe(II), As(V) to arsenite [As(III)], and sulfate to sulfide occurred. Less than 4% total As was released from iron-based media in the pe range between -3 and -7 due to reduction of As(V) to As(III) and reductive dissolution of ferric (hydr)oxides. Up to 38% As was released from the TiO2 adsorbent, which occurred at extremely low redox potential (i.e., pe<-6). The findings of this study will improve our ability to predict arsenic mobility when As-containing spent media are disposed of in landfills and the environment.     

Durability of a coating containing titanium dioxide for the photocatalytic degradation of diclofenac in water with UV‐A irradiation

A novel catalyst was used for lab scale photocatalytic experiments. It was a carbon doped titanium dioxide which was designed to create an energy efficient photocatalytic process. The titanium dioxide is able to absorb UV‐A radiation and parts of the visible light spectrum. The catalyst was immobilized to a glass sheet. UV‐A radiation was used for the degradation of the pharmaceutical diclofenac in water to investigate the applicability of the catalyst to degrade organic micropollutants. With the given experimental setup hydroxyl radicals were generated and diclofenac was degraded below the limit of quantification. However, reaction rates are rather slow and the material properties of the catalyst showed the need of improvement. This is because the properties of the coating were influenced by the release of inorganic binder. Therefore, the coating and possibly the titanium dioxide were washed off and the reaction rates decreased drastically after 80 hours of use.     

利用钛白废酸从粉煤灰中提取铝的研究

介绍了用工业钛白废酸提取粉煤灰中铝的新技术 ,试验研究了浸出过程中各因素对浸出率的影响 ,提出了最佳浸出工艺条件 .这为用钛白废酸提取粉煤灰中铝提供了新的方法 ,并为综合利用钛白废酸和粉煤灰又开辟了一个新的途径 .利用钛白废酸从粉煤灰中提取铝将具有较大的环境、经济和社会效益 .     

机械力活化制备碳酸钙/TiO2复合颗粒材料及表征

采用液相机械力活化的方法制备了碳酸钙/TiO2复合颗粒材料,考察了研磨介质、浆料浓度等因素对产物的影响,通过碳酸钙/TiO2的性能测试对颜料进行了综合评价。结果表明,碳酸钙/TiO2具有类钛白粉的颜料性质,金红石型钛白RS含量40%的颜料性能指标为遮盖力22.8g/cm2、吸油量22.5g/100g、白度95.50%。     

Removal of chlorine dioxide disinfection by-products by ferrous salts

Chlorine dioxide when used as an effective disinfectant forms undesirable disinfection by-products, i.e. chlorite and chlorate ions. The aim of this research was to study the removal of these ions by ferrous ions in the presence or absence of oxygen. The efficiency of Fe+2 for ClO2- and ClO3- removal was followed by a determination of their initial and final concentrations, pH and delta Fe+2 consumed/delta ClO2- removed ratios. The optimal weight ratio of delta Fe+2 consumed/delta ClO2- removed for complete ClO2 removal was found to be close to the theoretical calculated value of 3.31. It was proved that ferrous salts can reduce chlorite ions to harmless Cl- ions. This method can be recommended as a part of ClO2 disinfection to ensure safe drinking water, with no harm to water consumers and to the environment.     

纳米二氧化钛材料用于路面除雪的可行性分析

分析了目前公路积雪的清除方法中存在的弊端,简述了新型路面除雪材料应具有的特征,研究了纳米二氧化钛的材料性能,经过实验分析,指出在道路路面材料中加入纳米二氧化钛对路面积雪的消除和降低环境污染有积极意义.