强化泡沫排液下浮选富集和回收工程纳米颗粒

鉴于水体中工程纳米颗粒（ENP）的环境毒性与潜在价值,高效富集/回收ENP是其资源化处理的重要课题。为了突破浮选ENP中富集程度低且后续分离难度大的技术瓶颈,本文基于强化泡沫排液建立了富集/回收ENP的浮选法。以TiO₂纳米颗粒（TNP）为研究对象、十六烷基三甲基溴化铵（CTAB）为捕收剂和起泡剂,构筑了正八边形中空棱台（RHP）构件强化泡沫排液,分别从持液率、气泡直径和富集比等方面探讨了RHP强化排液的效果,分析了其机理。实验结果表明,在RHP构件安装于泡沫相中部、pH9.0、CTAB浓度100mg/L和气速250mL/min的条件下,TNP的富集比和回收率分别达到48.3±2.4和98.2%±4.9%;与不添加RHP相比,浮选过程中持液率降低了72.1%,TNP富集比升高了68.9%。综上,本文开发的浮选法为有效治理ENP水污染提供了重要的理论指导和技术支持。     

O3/Fe-TiO2/UV净化室内气体污染物的研究

以硫化氢、氨气、甲醛、甲苯、正戊烷和丙酮作为室内气体污染物,采用臭氧协同光催化技术,选择TiO₂为光催化剂并掺杂Fe³⁺改性,考察TiO₂的改性和不同的气体流速、反应物初始浓度、相对湿度以及臭氧浓度对净化效率的影响。结果表明,当反应段气体流速为1 m/s,臭氧添加量为49.08 mg/m³,相对湿度小于50%,系统运行30 min时,O₃/Fe-TiO₂/UV技术对6种气体污染物的平均净化效率为65%。     

纳米TiO2光催化材料的合成及应用研究进展

本文扼要介绍了纳米TiO₂的光催化反应机理,讨论了掺杂纳米TiO₂光催化剂的几种方法以及TiO₂光催化技术在废水处理中的应用,并对纳米TiO₂催化剂的发展做出了展望。     

二氧化钛基光催化剂光催化降解有机污染物

不同行业产生的有机化合物会产生一系列有问题的废水污染物。由于其优异的特性,包括无毒、高光催化降解能力以及优异的热和化学稳定性,TiO₂基光催化剂是具有优异吸收性能的新型材料。然而,TiO₂在有机废水处理中的应用仍然存在挑战,例如颗粒聚集、质量转移受限、亲和力差、能带宽和回收困难。因此,需要对TiO₂基光催化剂进行更多的设计和优化,从而以更低的成本达到更高的去除效率。本文主要对影响TiO₂基光催化剂活性的各种参数如TiO₂的结构、pH值、颗粒大小、掺杂剂和添加剂的引入进行了深入的研究使其得到进一步的研究和发展。     

二氧化钛基光催化剂光催化降解有机污染物

不同行业产生的有机化合物会产生一系列有问题的废水污染物。由于其优异的特性,包括无毒、高光催化降解能力以及优异的热和化学稳定性,TiO₂基光催化剂是具有优异吸收性能的新型材料。然而,TiO₂在有机废水处理中的应用仍然存在挑战,例如颗粒聚集、质量转移受限、亲和力差、能带宽和回收困难。因此,需要对 TiO₂基光催化剂进行更多的设计和优化,从而以更低的成本达到更高的去除效率。本文主要对影响 TiO₂基光催化剂活性的各种参数如 TiO₂的结构、pH 值、颗粒大小、掺杂剂和添加剂的引入进行了深入的研究使其得到进一步的研究和发展。     

色氨酸辅助合成光催化活性增强的球形纳米TiO2

以L-色氨酸（L-Trp）为生物模板,采用简单水解及煅烧后制备了球形结构TiO₂纳米光催化剂。通过X射线衍射、扫描电子显微镜、红外光谱、紫外-可见漫反射光谱、光致发光光谱和N₂吸附-解吸等方法对制得的TiO₂纳米材料进行表征。在催化剂合成过程中,L-Trp作为生物模板发挥至关重要的作用,能够指导球形结构纳米TiO₂的形成。考察了不同煅烧温度下制备的TiO₂样品光催化活性,结果表明550℃时制备的TiO₂样品具有优异的光催化活性,紫外光照射30min对甲基橙溶液的降解率达到95%左右,主要是由于较大比表面积和球形结构的协同效应。光催化剂稳定性实验表明,所制备的TiO₂纳米材料可作为一种实用有效的光催化剂用于紫外光照射下降解有机染料。同时,对L-Trp辅助下球形结构TiO₂纳米颗粒的可能生长机理进行讨论。     

ZnFe2O4/TiO2纳米棒光催化剂的制备及其对甲基橙废水的脱色研究

采用水热法制备了ZnFe₂O₄纳米粒子,在碱性条件下水解钛酸丁酯组装得到ZnFe₂O₄/TiO₂纳米棒光催化剂,利用X-射线衍射仪(XRD)、扫描电镜(SEM)、振动样品磁强计(VSM)、N₂吸附-脱附仪及电化学工作站分别表征了ZnFe₂O₄/TiO₂纳米棒的晶型、形貌、磁性能、孔结构及电极性能,并研究了其对甲基橙废水的脱色效果。结果表明,ZnFe₂O₄具有尖晶石结构,而TiO₂是锐钛矿结构,二者组装为具有介孔结构的ZnFe₂O₄/TiO₂纳米棒光催化剂,比饱和磁化强度高达40.0 emu·g^-1;紫外光照射120 min后,ZnFe₂O₄/TiO₂纳米棒对甲基橙废水的脱色率...     

二氧化钛光催化降解甲基橙废水的研究进展

TiO₂光催化剂因具有无毒无害、活性高、热稳定性好、持续性长、廉价等特点,在降解有机污染物方面得到广泛应用。TiO₂光催化剂的改性和负载技术提高了光催化反应效果,解决了催化剂分离回收的问题。本文综述了离子掺杂改性和负载技术在制备新型二氧化钛光催化剂中的应用,以及对光催化降解甲基橙废水的效果的研究,为研制新型高效二氧化钛光催化剂提供新的思路和理论依据。     

非晶态等离子异质结纳米TiO2溶胶及其制备与应用

为使常规TiO₂光催化剂可见光利用率不佳的情况得到良好解决,探讨了一种非晶态等离子异质结纳米TiO₂溶胶的制备与应用。     

光催化剂对土壤中有机污染物的分解

研究掺杂型TiO₂光催化剂对土壤中有机污染物的分解效果及其催化剂的催化活性，考察不同金属离子掺杂型TiO₂光催化剂在土壤中加入量、光催化剂分散方式、光照时间、土壤的水分与厚度等因素的变化，通过超声萃取-高效液相色谱测定了光催化剂对有机污染物五氯酚的分解效果。结果显示，掺杂型TiO₂光催化剂的光催化活性不仅与自身对光的响应范围、吸收强度以及掺杂金属离子种类有关，还与晶体结构及分解的物质有关，表明光催化剂的催化活性是多方面因素共同作用的结果。     

Preparation and performances of mesoporous TiO2 film photocatalyst supported on stainless steel

Mesoporous TiO₂ film photocatalysts supported on stainless steel substrates were prepared using the sol–gel method with Ti(OC₄H₉)₄ as a precursor and poly ethylene glycol (PEG) as a structure-directing agent. Mesoporous TiO₂ film with a pore diameter of about 15 nm was obtained with the addition of PEG (molecular WEIGHT =400). The pore diameter of TiO₂film was varied with molecular weight of PEG additive. The structure-directing process was also discussed. Mesoscopically ordered inorganic/polymer composites were believed to form during the process. Compared to conventional TiO₂ film photocatalyst, the mesoporous TiO₂ film showed a good performance for the photo degradation of rhodamine B (RB) solution irradiated with UV light of 365 nm. The photo degradation constant of rhodamine B for mesoporous TiO₂ film photocatalyst can arrive at 22 times of that for conventional TiO₂ film photocatalyst. Also an excellent performance for the degradation of gaseous formaldehyde with mesoporous film photocatalyst was obtained. The photo degradation rate of gaseous formaldehyde for mesoporous TiO₂ film photocatalyst can arrive at six times of that for conventional TiO₂ film photocatalyst.     

Low temperature preparation and visible light photocatalytic activity of mesoporous carbon-doped crystalline TiO2

A visible-light-active TiO₂ photocatalyst was prepared through carbon doping by using glucose as carbon source. Different from the previous carbon-doped TiO₂ prepared at high temperature, our preparation was performed by a hydrothermal method at temperature as low as 160 °C. The resulting photocatalyst was characterized by XRD, XPS, TEM, nitrogen adsorption, and UV–vis diffuse reflectance spectroscopy. The characterizations found that the photocatalyst possessed a homogeneous pore diameter about 8 nm and a high surface area of 126 m²/g. Comparing to undoped TiO₂, the carbon-doped TiO₂ showed obvious absorption in the 400–450 nm range with a red shift in the band gap transition. It was found that the resulting carbon-doped TiO₂ exhibits significantly higher photocatalytic activity than the undoped counterpart and Degussa P25 on the degradation of rhodamine B (RhB) in water under visible light irradiation (λ > 420 nm). This method can be easily scaled up for industrial production of visible-light driven photocatalyst for pollutants removal because of its convenience and energy-saving.     

N、Bi共掺杂的TiO_2可见光光催化剂的制备及其光催化性能

采用溶胶-凝胶法制备系列BixTi1-xO_2光催化剂以及N和Bi共掺杂Ti O_2光催化剂,采用XRD、UV-Vis、N2-物理吸附和TEM等对催化剂进行微观结构表征,以普通节能灯为光源,考察催化剂光催化氧化室内甲醛的性能。结果表明,在Bi掺杂的Ti O_2光催化剂体系中,Bi0.15Ti0.85O_2光催化剂催化降解甲醛效果最佳,400℃焙烧2.5 h,节能灯光照48 h,可将(1.05±0.05)mg·m-3甲醛降解至0.08 mg·m-3,甲醛转化率92.8%,达到室内空气质量标准。当N与Bi共掺杂时,节能灯光照24 h,Bi0.15Ti0.85O_2-N(0.2)光催化剂表现出最佳的光催化氧化降解甲醛性能,即可将甲醛由(1.05±0.05)mg·m-3降解至0.082 mg·m-3,甲醛转化率达92.0%,较Bi0.15Ti0.85O_2催化剂光催化效率提高50%。     

The preparation of coupled WO3/TiO2 photocatalyst by ball milling

The coupled photocatalyst WO₃/TiO₂ is prepared by ball milling by doping WO₃ into TiO₂ and using H₂O solution as disperser. The coupled photocatalyst WO₃/TiO₂ is characterized by UV–VIS diffuse reflection spectrum, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM). The results show that the optimum percentage of WO₃ doped is 3% and that the photocatalytic activity of the coupled WO₃/TiO₂ photocatalyst is much higher than that of TiO₂ and WO₃–TiO₂ with no ball milling. Compared with TiO₂, the photoexcited wavelength range of the WO₃/TiO₂ photocatalyst red-shifts about 50 nm, and the light absorption intensity is also improved. The crystal phase of TiO₂ is not changed and new crystal phases are not found during the process of ball milling. WO₃ and TiO₂ coupled highly, forming the WO₃/TiO₂ photocatalyst. The increased photocatalytic activity of the coupled photocatalyst may be attributed to the enhance charge separation efficiency and the extend wavelength range of photoexcitation.     

可见光光催化剂的研究进展

综述TiO_2、改性TiO_2光催化剂和非TiO_2体系光催化剂在可见光催化领域的研究进展,概述了光催化剂的光催化原理和应用方向,针对可见光光催化剂发展现状中存在的量子效率和可见光利用率低、且回收难等问题进行阐述,并指出制备组成可控、形貌可控、易于回收利用且可见光利用率高的新型光催化剂是研究首要方向。     

Development of the efficient TiO2 photocatalyst in photoassisted selective catalytic reduction of NO with NH3

Photoassisted selective catalytic reduction (photo-SCR) of NO with NH₃ in the presence of O₂ takes place at room temperature over TiO₂ photocatalyst. From the results of photo-SCR reaction over various TiO₂, we found that JRC-TIO-11 exhibited the best activity. The reaction activity correlated to the amount of acid sites of TiO₂, but did not depend on the specific surface area and crystal diameter. The mixture of rutile and anatase shows higher activity than any of the corresponding TiO₂ single phase catalyst.     

Development of air purification device through application of thin-film photocatalyst

TiO₂ photocatalyst was prepared by hydrothermal method using titanium isopropoxide as a precursor. This photocatalyst had higher content of anatase structure and larger surface area than commercial P-25 photocatalyst. The air purification device with a filter coated with photocatalyst film was excellent in its capabilities to decompose organic materials and to kill germs. When the device was installed in hospitals, it was powerful for the sterilization of floating germs in the air. In addition, the number of germs after 7 months operation was almost the same as that obtained in the first operation.     

Mechanistic approach of the combined (iron–TiO2) photocatalytic system for the degradation of pollutants in aqueous solution: an attempt of rationalisation

Kinetics of oxidative photodegradation of Monuron (3-(4-chlorophenyl)-1,1-dimethylurea) in different photocatalytic systems (iron, TiO₂ and combined system iron + TiO₂) were investigated and compared. The influence of iron addition on TiO₂ photocatalyst and of TiO₂ on the photocatalytic cycle Fe(III)/Fe(II) were carefully studied. A very positive effect of iron addition was observed. This phenomenon was more and more pronounced when TiO₂ concentration was lower. In a suspension of TiO₂ (24 mg L⁻¹) with addition of Fe(III) (3 × 10⁻⁴ mol L⁻¹) the measured rate constant was similar to that obtained in a suspension of TiO₂ with a concentration more than 20 times higher (500 mg L⁻¹). The mechanistic approach carried out in this study allows us to identify the main reactions governing the combined system and a photochemical cycle was proposed. The optimisation of the photocatalytic systems was obtained when each photocatalyst plays a specific role: Fe(III) as a main OH radicals source and TiO₂ as an oxidizing agent of Fe(II).     

Photocatalytic degradation of omethoate using NaY zeolite-supported TiO2

The degradation of omethoate was conducted using H₂O₂ as oxidant, TiO₂ supported on NaY zeolite as photocatalyst and a 300 W lamp as light source. The effect of the calcination temperature of the photocatalyst, the amount of TiO₂ loaded on NaY zeolite, the photocatalyst amount, the pH value and the radiation time on the degradation ratio of omethoate were investigated. The results show that TiO₂/NaY zeolite photocatalyst prepared by sol-gel method had good photocatalysis. The photocatalytic optimum oxidation conditions of omethoate are as follows: the calcination temperature of the photocatalyst is 550°C,the amount of TiO₂ loaded on NaY zeolite is 35.2 wt-%, the amount of photocatalyst is 5 g/L, pH=8 and the radiation time is 180 min. Under these conditions, the removal ratio of omethoate is up to 93%.     

Oil recovery from oil in water emulsions using a flotation column

A flotation column was used to recover oil from oil in water emulsions. The feed oil concentrations investigated were relatively high, in the range of 0.25 to 8 percent by volume. Previous studies using conventional flotation cells dealt with very dilute systems where the oil concentration was less than 0.1 percent by volume. The oil recovery was found to decrease with an increase in the feed oil concentration. The addition of wash water to the froth zone of the column had little effect on the oil recovery. The oil recovery decreased with increasing feed flow rate and surfactant concentration. The effect of increasing the gas flow rate was to initially increase the oil recovery. The oil recovery data were analyzed using a kinetic model. The order of the flotation kinetics was found to be 0.6. The gas hold-up behaviour of the recovery and the froth zones of the flotation column is found to correlate well with the drift-flux model.