改性TiO_2光催化降解三苯甲烷类污染物

以硫酸钛为原料采用水热法制备了掺Fe3＋TiO2晶体粉末,采用X射线衍射仪（XRD）对样品的结构进行了表征。在可见光条件下,用溴酚蓝、甲基绿、甲基蓝、孔雀石绿、甲基紫和碱性品红等6种典型三苯甲烷类化合物为目标降解物,研究了以自制的掺Fe3＋TiO2晶体粉末对它们的催化降解作用。实验结果表明,制备的掺Fe3＋TiO2晶体属于锐钛矿型。6种化合物的光催化降解反应遵循拟一级动力学规律,且可用Langmuir-Hinshelwood（L-H）动力学模型描述,其表观反应速度常数（k）的大小顺序为：溴酚蓝〈甲基绿〈甲基蓝〈孔雀石绿〈甲基紫〈碱性品红,大小变化次序与其半衰期t1/2成反比,并从分子结构上对它们的降解规律进行定性解释。     

催化臭氧氧化染料溶液的研究

采用催化臭氧化技术降解染料废水,以甲基紫溶液为目标污染物,研究了过渡型金属离子的类型,Fe2+的浓度,溶液初始pH值,染料浓度和正丁醇等因素对其降解率的影响。实验结果表明:臭氧氧化甲基紫溶液的过程中,加入一定浓度的过渡型金属离子对甲基紫的去除具有促进作用;当臭氧浓度为16 mg/L,一定浓度范围内,Fe2+催化臭氧化的效果随着浓度的增加而增加,但Fe2+浓度为13 mg/L时,甲基紫的降解率下降;在酸性范围时,pH值增大其降解率会减小;染料浓度增加,甲基紫的降解率减小,但是其绝对降解值会增加;正丁醇的加入抑制氧化反应的进行,甲基紫的降解率下降,说明催化臭氧化过程中有羟基自由基产生。染料降解过程符合一级反应动力学规律。     

改性TiO2对X-3B的光催化性能及其降解动力学研究

以活性艳红X-3B为模型化合物,比较了改性前后TiO2光催化活性的变化.试验结果表明,通过改性大大提高了TiO2的光催化活性,Fe3+和Ag+的掺杂量均有一个最佳值,在试验的掺杂范围内Fe3+和Ag+的最佳掺杂量分别是0.1%和0.05%.对其宏观降解反应动力学的研究表明,X-3B在TiO2、Fe3++TiO2和Ag++TiO2 3种催化剂上的光催化降解动力学均能很好地符合Langmiur-Hinshelwood动力学模型.其表观反应速率常数的大小顺序依次是Ag++TiO2＞Fe3++TiO2＞TiO2;吸附平衡常数则是Fe3++TiO2和Ag++TiO2两者基本相等,两者均比纯TiO2大2～3倍.     

Fe~(3+)掺杂TiO_2/凹凸棒复合材料的光催化性能

采用酸催化的溶胶-凝胶法制备了一系列Fe3+掺杂TiO2/凹凸棒(Fe3+-TiO2/ATP)复合光催化剂材料。在可见光条件下,以亚甲基蓝(MB)溶液的光催化降解反应,评价了样品的光催化性能,研究了TiO2负载量、Fe3+掺杂量和焙烧温度对复合材料光催化性能的影响。在单因素实验的基础上,采用正交实验设计(L25(53))优化了催化剂的制备条件。光催化实验结果表明,MB在复合材料上的光催化降解反应遵循Langmuir-Hinshelwood(L-H)动力学模型。正交实验结果表明,当TiO2负载量为15%、Fe3+掺杂量为0.5%和焙烧温度为550℃时,得到的复合材料对MB的光催化降解效率最佳,测得表观反应速率常数kapp为6.09×10-3min-1,反应4 h后MB的降解率(Dt)可达75.88%,相同实验条件下与P25(1.51×10-3min-1)相比较,反应速率提高了4.03倍,降解率提高了45.05%。另外,复合材料的沉降性能优于P25,易于分离,是一类有应用前景的复合光催化剂。     

亚甲基蓝表面修饰纳米TiO2降解造纸废水动力学

以亚甲基蓝(MB)作为表面修饰剂,采用简单的化学吸附法制备亚甲基蓝表面修饰的纳米TiO2光催化剂(TiO2-MB)。经表面修饰后,TiO2-MB光催化剂波长响应范围红移至可见光区575 nm处。探讨了光催化剂量、光照时间和溶液pH值对TiO2-MB光催化降解造纸废水的影响;研究了纳米TiO2-MB对造纸废水的暗吸附规律和光降解性能。结果表明:纳米TiO2-MB对造纸废水的吸附规律都较好地符合Langmuir和Freundlich吸附等温模型,属于吸热反应;光催化降解动力学符合Langmuir-Hinshelwood动力学模型。在160 W高压汞灯光照80 min,3.0 g/L纳米TiO2-MB光催化降解pH=2.0的造纸废水(COD:2 069.8 mg/L),COD去除率可达94.7%,处理效果远高于避光条件下。光催化剂经8次使用仍具有较高的催化活性。     

复合型CoO/TiO2光催化剂降解亚甲基蓝动力学研究

以钛酸四丁酯为前驱体,采用溶胶凝胶法,制备了CoO掺杂的TiO2光催化剂。利用X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、紫外可见漫反射（UV-vis DRS）对催化剂进行了分析、表征。以中压汞灯为光源,研究了亚甲基蓝（MB）在CoO/TiO₂微粒水悬浮液中的降解动力学。结果表明：所制备的催化剂活性组分主要是锐钛矿型的二氧化钛和CoO固溶体,粒径为25～30 nm,分布均匀。亚甲基蓝的光催化降解动力学满足一级动力学,在一定的浓度范围内,反应速率常数随初始浓度增大而减少,适当的掺钴量可以有效地提高TiO₂光催化活性,其最佳掺杂量重量百分比为0.25%。     

复合型CoO／TiO2光催化剂降解亚甲基蓝动力学研究

以钛酸四丁酯为前驱体,采用溶胶凝胶法,制备了CoO掺杂的TiO2光催化剂。利用X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、紫外可见漫反射（UV—visDRS）对催化剂进行了分析、表征。以中压汞灯为光源,研究了亚甲基蓝（MB）在CoO／TiO2微粒水悬浮液中的降解动力学。结果表明：所制备的催化剂活性组分主要是锐钛矿型的二氧化钛和CoO固溶体,粒径为25～30nm,分布均匀。亚甲基蓝的光催化降解动力学满足一级动力学,在一定的浓度范围内,反应速率常数随初始浓度增大而减少,适当的掺钴量可以有效地提高TiO2光催化活性,其最佳掺杂量重量百分比为0．25％。     

Fe/TiO2光催化降解水溶液中的4-氯苯酚

以TiO2-P25及FeC2O4为前驱物制备了Fe3 掺杂TiO2光催化剂--Fe/TiO2.X射线衍射结果表明,500 ℃煅烧温度下的Fe/TiO2主要是锐态矿晶型,当掺Fe3 量为0.5%(质量分数,下同)时,Fe3 以取代掺杂形式进入TiO2晶格,而当掺Fe3 量达5.0%时,则出现α-Fe2O3的特征衍射峰;900 ℃煅烧温度下的Fe/TiO2则均为金红石晶型,掺Fe3 量达2.0%～5.0%时,出现Fe2TiO5的特征衍射峰.4-氯苯酚的光催化实验结果表明,煅烧温度及Fe3 掺杂量对Fe/TiO2的光催化活性有显著影响,以煅烧温度500 ℃及掺Fe3 量0.5%的Fe/TiO2为光催化剂,反应80 min,4-氯苯酚的降解率达100%,总有机碳去除率约95%.     

纳米Au/TiO2复合物光催化降解亚甲基蓝

以纳米金棒为掺杂物,采用溶胶-凝胶法制备了纳米Au/TiO2复合材料,在紫外光下对亚甲基蓝溶液进行光催化降解。结果表明,在紫外光下,Au/TiO2复合物对亚甲基蓝的脱色率最高可达99.6%,是纯TiO2的1.3倍。这主要归结于掺杂纳米尺寸的Au可增加TiO2对光的吸收以及减少电子-空穴对的复合,由此提高其光催化能力。     

零价铁(Fe~0)共存下TiO_2光催化降解特性的研究

针对TiO2光催化反应中易出现电子-空穴对(e--h+)的复合、而Fenton技术又面临铁污泥的问题,向TiO2光催化反应中加入零价铁(Fe0)。通过调节溶液pH,使Fe0缓释Fe2+,且反应之后的pH仍能满足TiO2光催化反应所需。溶液中的Fe2+,一方面能减弱TiO2光催化产生的e--h+的复合,提高TiO2光催化反应的效率;另一方面,在紫外灯照射下也可以起到光Fenton降解作用。研究结果表明,Fe0共存下TiO2光催化对废水的降解率高于单独使用TiO2光催化或光Fenton对废水的降解率。对Fe0共存下TiO2光催化降解废水的褪色率的动力学研究表明,该反应属于三级动力学反应,且其对有机物的降解具有TiO2光催化和光Fenton加合增效的效果。     

Electrochemical decolourisation of structurally different dyes

The electrochemical decolourisation of structurally different dyes (bromophenol blue, indigo, poly R-478, phenol red, methyl orange, fuchsin, methyl green and crystal violet) by means of the application of DC electric current was assessed. It was found that the electrochemical process allowed a colour removal of all dyes studied, although the decolourisation rate largely depended on the chemical structure of the different dyes. Nearly complete decolourisation was achieved for bromophenol blue followed by methyl orange and methyl green, whereas phenol red was hardly decolourised (30% in 60 min). In mixtures of two dyes, the decolourisation rate became similar for both dyes. However, the addition of a redox mediator, (Co(2+/3+)) clearly enhanced the degradation rate of all tested dyes, but the simplest dye molecules were attacked firstly, followed by dyes with more complex chemical structures. The results revealed the suitability of the process to effectively decolourise wastewaters from dyeing process.     

银钛共负载型光催化材料降解甲基橙废水简

以膨胀珍珠岩为载体,采用溶胶凝胶法对其进行负载,制备出不同类型的光催化材料（TiO₂-EP、Ag⁺-TiO₂-EP）,并在模拟日光条件下,研究其对甲基橙溶液的降解效果。结果表明,浸渍3次且担载0.04% Ag⁺的负载型TiO₂光催化活性最高,在光催化剂用量为0.3 g,20 mL初始浓度为10 mg/L甲基橙溶液光照4 h后降解率可达81.6%,且甲基橙的光催化降解服从一级动力学方程。回收3次后仍有较强的活性,其2 h降解率为24.8%。     

The enhancement of photodegradation efficiency using Pt–TiO2 catalyst

This study investigates the mechanism of photosensitization and the recombination of excited electron–hole pairs affected by depositing platinum (Pt) on the surface of titanium dioxide (TiO₂). A new catalyst of Pt–TiO₂ was prepared by a photoreduction process. Being model reactions, the photocatalytic oxidation of methylene blue (MB) and methyl orange (MO) in aqueous solutions using the Pt–TiO₂ catalyst was carried out under either UV or visible light irradiation. The experimental results indicate that an optimal content of 0.75%Pt–TiO₂ achieves the best photocatalytic performance of MB and MO degradation and that the Pt–TiO₂ catalyst can be sensitized by visible light. The interaction of Pt and TiO₂ was investigated by means of UV–Vis absorption spectra, photoluminescence emission spectra, and X-ray photoelectron emission spectroscopy. The Pt⁰, Pt²⁺ and Pt⁴⁺ species existing on the surface of Pt–TiO₂, and the Ti³⁺ species existing in its lattice may form a defect energy level. The Pt impurities, including Pt, Pt(OH)₂, and PtO₂, and the defect energy level absorb visible light more efficiently in comparison with the pure TiO₂ and hinder the recombination rate of excited electron–hole pairs.     

Fe/Ce/沸石负载型类芬顿催化剂制备及其特性

采用柠檬酸盐溶胶-凝胶法制备了Fe/Ce/沸石负载型芬顿催化剂,通过透射电镜(TEM)和X射线衍射(XRD)对其进行表征,并将其作为非均相类芬顿催化剂处理孔雀石绿染料溶液。研究表明,通过掺杂Ce,可提高催化剂颗粒分散度和催化剂表面的氧气含量,进而提高催化活性。在催化剂投加量3.0 g/L,H2O2投加量67 mg/L,pH=8.0的条件下,反应30 min后,浓度为150 mg/L的孔雀石绿溶液脱色率可达97.3%。     

纳米二氧化钛复合石墨烯催化剂的制备及处理染料废水

以硫酸钛为原料,采用共沉淀法,制备了一系列纳米二氧化钛复合石墨烯催化剂,采用XRD和FTIR对样品进行表征。通过紫外光照射亚甲基蓝溶液光催化降解实验,研究石墨烯的加入量对TiO2光催化性能的影响,结果表明,TiO2-GO-5具有最佳的光催化性能。在pH=6.00、TiO2-GO-5的投加量为0.070 g/50 mL、光照3 h条件下,100 mg/L亚甲基蓝溶液的脱色率达到最大值为90.52%。     

Solar CPC pilot plant photocatalytic degradation of bisphenol A in waters and wastewaters using suspended and supported-TiO2. Influence of photogenerated species

Photocatalytic degradation of bisphenol A (BPA) in waters and wastewaters in the presence of titanium dioxide (TiO₂) was performed under different conditions. Suspensions of the TiO₂ were used to compare the degradation efficiency of BPA (20 mg L^?1) in batch and compound parabolic collector (CPC) reactors. A TiO₂ catalyst supported on glass spheres was prepared (sol–gel method) and used in a CPC solar pilot plant for the photodegradation of BPA (100 μg L^?1). The influence of OH·, O₂ ^·?, and h ⁺ on the BPA degradation were evaluated. The radicals OH· and O₂ ^·? were proved to be the main species involved on BPA photodegradation. Total organic carbon (TOC) and carboxylic acids were determined to evaluate the BPA mineralization during the photodegradation process. Some toxicological effects of BPA and its photoproducts on Eisenia andrei earthworms were evaluated. The results show that the optimal concentration of suspended TiO₂ to degrade BPA in batch or CPC reactors was 0.1 g L^?1. According to biological tests, the BPA LC₅₀ in 24 h for E. andrei was of 1.7?×?10^?2 mg cm^?2. The photocatalytic degradation of BPA mediated by TiO₂ supported on glass spheres suffered strong influence of the water matrix. On real municipal wastewater treatment plant (MWWTP) secondary effluent, 30 % of BPA remains in solution; nevertheless, the method has the enormous advantage since it eliminates the need of catalyst removal step, reducing the cost of treatment.     

Heterogeneous UV/Fenton degradation of bisphenol A catalyzed by synergistic effects of FeCo2O4/TiO2/GO

A new method for bisphenol A (BPA) degradation in aqueous solution was developed. The characteristics of BPA degradation in a heterogeneous ultraviolet (UV)/Fenton reaction catalyzed by FeCo₂O₄/TiO₂/graphite oxide (GO) were studied. The properties of the synthesized catalysts were characterized using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry. FeCo₂O₄ and TiO₂ were grown as spherical shape, rough surface, and relatively uniform on the surface of GO (FeCo₂O₄/TiO₂/GO). Batch tests were conducted to evaluate the effects of the initial pH, FeCo₂O₄/TiO₂/GO dosage, and H₂O₂ concentration on BPA degradation. In a system with 0.5 g L⁻¹ of FeCo₂O₄/TiO₂/GO and 10 mmol L⁻¹ of H₂O₂, approximately 90 % of BPA (20 mg L⁻¹) was degraded within 240 min of UV irradiation at pH 6.0. The reused FeCo₂O₄/TiO₂/GO catalyst retained its activity after three cycles, which indicates that it is stable and reusable. The heterogeneous UV/Fenton reaction catalyzed by FeCo₂O₄/TiO₂/GO is a promising advanced oxidation technology for treating wastewater that contains BPA.

     

Cu/La共掺杂TiO2光催化氧化水中的氨氮

采用水解-沉淀法制备了Cu/La共掺杂纳米TiO2催化剂,利用XRD、XPS和BET技术对其进行表征,并考察了在紫外灯下,共掺杂TiO2对氨氮的光催化氧化工艺条件。物相结构和比表面积测试结果表明,共掺杂催化剂具有较好的锐钛矿晶型,孔径分布为4～8 nm,Cu/La共掺杂TiO2La以La3+,Cu是以Cu2+、Cu+的形式掺杂进入TiO2的晶格。光催化实验表明:所得改性光催化剂对氨氮的去除及焦化废水的处理均具有较高的催化活性。