负载型纳米TiO2光催化降解水中微量溶解性间二甲苯

以高压汞灯为光源 ,采用浸涂 -烧结法制备的负载型纳米TiO2 作为光催化剂 ,通过对水中微量溶解性间二甲苯的光催化氧化过程的研究表明 ,初始浓度在 6 .6 8— 17.36mg/L的范围内 ,间二甲苯的光催化反应遵循表观一级反应动力学规律 ,反应的表观速率常数随溶液初始浓度的增大而减小 ,半衰期则随初始浓度的增大而增加 ,经 1.5h反应后 ,溶液中间二甲苯的去除率从 17.36mg/L的 5 4 .4 4 %增加到 6 .6 8mg/L的 75 .90 %。     

TiO2光催化氧化脱除模拟烟气中的NOx

采用P25纳米TiO2为催化剂,对NOx浓度360 mg/m3的模拟烟气进行了光催化氧化实验研究,以期为此种方法在电厂烟气脱硝方面的应用提供依据。经SEM、XRD等表征手段,探讨了催化剂晶型尺寸对光催化的作用。实验考察了光催化反应过程规律以及负载量、光照度、NO初始浓度、O2含量、相对湿度和停留时间对光催化氧化效率的影响。结果表明,光催化反应是瞬态到稳态的过程,其催化效率与上述影响因子有密切关系。实验最优条件下NOx的脱除率为46%,但只需适当提高氧化效能,便能达到理想的效果。     

Photocatalytic oxidation of NOx gases using TiO2: a surface spectroscopic approach

The bandgap of solid-state TiO2 (3.2 eV) enables it to be a useful photocatalyst in the ultraviolet (lambda < 380 nm) region of the spectrum. A clean TiO2 surface in the presence of sunlight therefore enables the removal of harmful NOx gases from the atmosphere by oxidation to nitrates. These properties, in addition to the whiteness, relative cheapness and non-toxicity, make TiO2 ideal for the many de-NOX catalysts that are currently being commercially exploited both in the UK and Japan for concrete paving materials in inner cities. There is need, however, for further academic understanding of the surface reactions involved. Hence, we have used surface specific techniques, including X-ray photoelectron spectroscopy and Raman spectroscopy, to investigate the NOx adsorbate reaction at the TiO2 substrate surface.     

Photocatalytic oxidation of NOx using composite sheets containing TiO2 and a metal compound

The photocatalytic oxidation of nitrogen oxides (NO(x)) over titanium dioxide (TiO(2)) sheets containing metal compounds (MCs) had been studied. Calcium oxide (CaO), magnesium oxide (MgO), calcium carbonate (CaCO(3)), aluminium oxide (Al(2)O(3)) and ferric oxide (Fe(2)O(3)) were used as MCs. Al(2)O(3) and Fe(2)O(3) added to the TiO(2) sheet did not affect the photooxidation of nitrogen oxides (NO(x)). The CaO sheet treated with TiO(2) sol had the greatest efficiency as a NO(x) remover under UV irradiation. It is believed that CaO has a high adsorptivity for nitrogen dioxide (NO(2)) and nitric acid (HNO(3)). The amount of NO(x) removed by a TiO(2) sheet including MC showed a tendency to increase with increasing pH of the MC suspension, i.e. there is a good correlation between the alkalinity of the MC and the retention of NO(2) and HNO(3).     

Photocatalytic oxidation of gaseous DMF using thin film TiO2 photocatalyst

The heterogeneous photocatalytic oxidation of gaseous N,N'-dimethylformamide (DMF) widely used in the manufacture of synthetic leather and synthetic textile was investigated. The experiments were carried out in a plug flow annular photoreactor coated with Degussa P-25 TiO2. The oxidation rate was dependent on DMF concentration, reaction temperature, water vapor, and oxygen content. Photocatalytic deactivation was observed in these reactions. The Levenspiel deactivation kinetic model was used to describe the decay of catalyst activity. Fourier transform infrared (FTIR) was used to characterize the surface and the deactivation mechanism of the photocatalyst. Results revealed that carbonylic acids, aldehydes, amines, carbonate and nitrate were adsorbed on the TiO2 surface during the photocatalytic reaction. The ions, NH4+ and NO3-, causing the deactivation of catalysts were detected on the TiO2 surface. Several treatment processes were applied to find a suitable procedure for the regeneration of catalytic activity. Among these procedures, the best one was found to be the H2O2/UV process.     

TiO2光催化氧化十二烷基苯磺酸钠

家用或工业用表面活性剂的排放是河流、湖泊和海洋的主要污染源之一,其中十二烷基苯磺酸钠比较具有代表性.用TiO2光催化其降解具有无毒、快速、矿化彻底、操作成本低、催化剂价廉易得、无二次污染等优点,应用前景广阔.本文就该反应的机理、反应动力学以及影响反应的因素作了简要概述.     

纳米TiO2薄膜在不同陶瓷表面的负载及其光催化性能研究

利用2种不同表面处理的陶瓷作为载体,用溶胶凝胶法在其表面进行了纳米TiO2光催化薄膜的负载.采用X射线衍射法(XRD)、X射线光电子能谱仪(XPS)和扫描电镜(SEM)对薄膜的粒径、横断面及表面组成进行了表征和分析,结果表明,TiO2的平均粒径约为15 nm,釉面陶瓷TiO2薄膜分布均匀,膜厚约为300 nm;无釉陶瓷TiO2薄膜分布不均,膜层不明显;2种载体中的一些基质离子在TiO2薄膜有渗透.苯酚的降解实验表明,以2种不同表面处理的陶瓷为载体的TiO2薄膜对苯酚的降解均符合一级反应动力学,就催化活性而言,TiO2/釉面陶瓷＞TiO2/无釉陶瓷,分析认为基质渗透的Ca2 有降低TiO2光催化活性的作用;该薄膜对实际生产多菌灵废水具有催化降解作用.重复降解实验20次,TiO2/釉面陶瓷和TiO2/无釉陶瓷对苯酚的去除率仅分别降低9%和6%.     

纳米TiO2薄膜在不同陶瓷表面的负载及其光催化性能研究

利用2种不同表面处理的陶瓷作为载体，用溶胶凝胶法在其表面进行了纳米TiO2光催化薄膜的负载。采用X射线衍射法（XRD）、X射线光电于能谱仪（XPS）和扫描电镜（SEM）对薄膜的粒径、横断面及表面组成进行了表征和分析，结果表明，TiO2的平均粒径约为15nm，釉面陶瓷TiO2薄膜分布均匀，膜厚约为300nm；无釉陶瓷TiO2薄膜分布不均，膜层不明显；2种载体中的一些基质离子在TiO2薄膜有渗透。苯酚的降解实验表明，以2种不同表面处理的陶瓷为载体的TiO2薄膜对苯酚的降解均符合一级反应动力学，就催化活性而言，TiO2／釉面陶瓷〉TiO2／无釉陶瓷，分析认为基质渗透的Ca^2＋有降低TiO2光催化活性的作用；该薄膜对实际生产多菌灵废水具有催化降解作用。重复降解实验20次，TiO2／釉面陶瓷和TiO2／无釉陶瓷对苯酚的去除率仅分别降低9％和6％。     

Photocatalytic oxidation of nitrogen oxides using TiO2 loading on woven glass fabric

TiO2 loading on woven glass fabric is applied to treat nitrogen oxides (NOx) by photocatalytic oxidation (PCO). In this paper, the PCO behavior of NO at high concentrations was studied by PCO of NOx at source levels (20-168 ppm). The PCO efficiency reached 27% in this experiment, while the inlet NOx concentration was 168 ppm (147 ppm NO). The dependency of the reaction rate on several key influencing factors (relative humidity, space time, inlet concentration, oxygen percentage) was also studied. The results illustrate that the resulting hydroxyl radical and active oxide play an important role in the oxidation of NOx. The reactions are limited by the thermodynamic equilibrium after ca. 15s space time. A possible explanation for the catalyst deactivation is the accumulation of nitric acid and nitrous acid on the TiO2 surface during the PCO of NOx. However, the photocatalytic activity can be recovered with a simple heat treatment. The results from the study of the effect of the inlet concentration were described with the Langmuir-Hinshelwood model.     

ClO2氧化/TiO2复合吸附剂协同体系处理印染废水的实验研究

利用ClO2 氧化/TiO2 复合吸附剂协同体系对处理实际印染废水进行了实验研究.结果表明,对于COD为750 mg/L、色度为250倍、SS为100 mg/L的1 000 mL印染废水,当溶液pH为4.0、ClO2 用量20 mg/L、TiO2 复合吸附剂用量2.5 g、反应时间和吸附时间分别为2、8 min时,处理后的废水COD＜100 mg/L、色度＜40倍、SS＜70 mg/L,达到了《纺织染整工业水污染物排放标准》(GB 4287-92)排放要求.并对两者的协同机理进行了理论上的探讨.     

Fenton氧化法深度处理抗生素废水二级出水

采用Fenton氧化法对青霉素和土霉素混合废水二级处理出水进行深度处理,通过正交和单因素实验研究了废水初始反应pH值、H2O2投加量、Fe2+/H2O2摩尔比及反应时间等因素对废水处理效果的影响。实验结果表明,Fenton氧化法处理的最佳反应条件为:初始pH值4、H2O2(30%)投加量50 mL/L、Fe2+/H2O2摩尔比1/20和反应时间60 min,处理后出水COD小于120 mg/L,COD去除率在75%以上,急性毒性(HgCl2毒性当量)小于0.07 mg/L,满足《发酵类制药工业水污染物排放标准》(GB21903-2008)表2标准要求。     

Photocatalytic degradation of cellulose bleaching effluent by supported TiO2 and ZnO

A cellulose bleaching effluent (E1) was degraded in batch conditions by photocatalysis using TiO2 and ZnO supported on glass Raschig rings. The effluent was completely decolourised and the total phenol content was reduced by 85% after 120 min treatment with both catalysts. Partial mineralization of the organic matter was confirmed by total organic carbon (TOC) reduction, approximately 50%. The residual organic matter shows a low acute toxicity as compared to the initial values and AOX values are strongly reduced after the photocatalytic oxidation. Molecular mass distribution showed that high molecular mass compounds were almost completely degraded.     

负载TiO2浮石对污水处理厂二沉池出水的矿化与灭菌研究

城市污水处理厂第二沉淀池出水的污染物浓度较低,经过矿化及灭菌等深度处理后可以回用,从而减轻对淡水资源的需求。本实验采用溶胶-凝胶法制备了负载TiO2的浮石光催化剂,对城市污水处理厂第二沉淀池出水进行了矿化及灭菌处理研究。采用低压汞灯对处理水样照射2h,有机物降解率可以达到50％,灭菌效率达到100％。处理后的水可以作为农作物灌溉、城市绿化和娱乐用水。负载在浮石表面的TiO2薄膜经过10次的光催化循环实验后,没有明显破损,可以再次循环使用。TiO2浮石具有质轻、机械性能好和价格低等优点,该方法处理废水的适用浓度低,可以广泛应用于微污染水和城市污水处理厂出水的深度处理。     

臭氧高级氧化法降解生化尾水中喹啉

采用O_3、O_3/UV、O_3/H_2O_23种工艺对喹啉的去除、矿化效果,生化性提高及降解规律等方面进行了对比分析,结果表明,单独H_2O_2、单独UV不能有效地降解喹啉;单独O_3、O_3/H_2O_2对喹啉有一定的去除效果,但两者差别不大;反应时间为6 min时,喹啉去除率分别为78.7%和79%,反应30 min时,喹啉的矿化率为33.4%和38.2%;O_3/UV工艺明显优于前2种,在6 min内,喹啉基本降解完全,30 min矿化率超过90%;3种工艺的降解过程都很好地满足伪一级动力学规律,O_3/UV的表观反应速率常数(0.7204 min~(-1))大于单独O_3(0.2832 min~(-1))和O_3/H_2O_2(0.29 min~(-1))工艺的表观反应速率常数;采用O_3/UV工艺处理实际工业园区生化尾水,6 min内喹啉降解完全,30 min时,COD去除率为88%,TOC的去除率达到89%,UV254的去除率为96%,出水指标达到《城镇污水处理厂污染物综合排放标准》一级A标准。     

Highly efficient photocatalytic oxidation of antibiotic ciprofloxacin using TiO2@g-C3N4@biochar composite

Environmental Science and Pollution Research - In this present study, a novel indirect Z-scheme TiO2@g-C3N4@biochar (TiO2@g-C3N4@BC) composite photocatalyst was successfully fabricated and...     

二氧化钛光催化氧化杀菌的研究及进展

本文概括了光催化氧化杀菌的发展历史 ,以及最新的研究进展 ,综合分析了其杀菌机理和影响反应的各相关因素 ,并为今后的发展提出了一些看法     

Photocatalytic oxidation of soot by P25 TiO2 films

The photomineralisation of soot by P25 titania films is studied using FT-IR and the process shown to involve the oxidation of carbon to CO2 exclusively. The efficiency of this process is low, however, with a formal quantum efficiency of 1.1 x 10(-4) molecules of carbon oxidized per incident photon of UVA light. The cause of this low efficiency is attributed largely to the less than intimate contact between the fibrous soot layer and the surface of the photocatalyst.     

臭氧氧化二级出水回用于选矿浮选的适用性

为优化干旱矿区浮选单元的取水结构,降低市政污水处理厂二级出水的回用风险,以内蒙古某铜钼矿为代表性研究对象,采用臭氧氧化工艺对该区域市政污水处理厂二级出水进行深度处理,探讨其对水中病原微生物的去除效果,研究处理后的二级出水对浮选指标的影响以及相应的健康风险,评估氧化处理工艺的二级出水回用于选矿浮选单元的适用性。结果表明,二级出水中大肠杆菌浓度具有明显的季节分布性,最高浓度可达3.85 ×10⁶ 个·mL⁻¹,轮状病毒检出率为77.78%,直接回用具有一定风险;而且浮选用水的水质对浮选指标影响较大,随着COD、悬浮物浓度的下降,精矿中铜、钼的品位和回收率相应增加,浮选指标得到改善;采用臭氧氧化处理工艺二级出水,在臭氧投加量为6 mg·L⁻¹、氧化时间为10 min、不调节pH的情况下,二级出水中粪大肠杆菌衰减率可达3.44lg 个·L⁻¹。在该工艺条件下,使用处理后的二级出水进行浮选,浮选产品指标合格,且粪大肠杆菌单次暴露感染风险为4.71×10⁻⁸~1.35×10⁻⁶,年暴露感染风险为1.59×10⁻⁶~4.70×10⁻⁴,均为可接受水平。     

沸石负载Fe_3O_4光催化氧化去除水中苯酚

为了对水中苯酚的去除进行研究,通过离子交换法及液相沉积法在天然沸石上负载Fe3O4制备出一种具有较高反应活性的复合催化剂,采用X-射线衍射仪(XRD)、扫描电镜(SEM)等仪器对其结构和形貌进行表征,并利用复合催化剂进行非均相UV/Fenton反应处理模拟苯酚废水,考察不同因素对苯酚降解效果的影响。实验结果表明,在催化剂投加量为0.4 g/L,H2O2投加量为二分之一理论投加量,pH为3~10且室温的条件下,处理100 mg/L的模拟苯酚废水,60 min之内苯酚去除率可达90%以上。通过对催化剂的稳定性研究,发现经5次循环使用后,苯酚去除率均可保持在90%以上,具有良好的循环使用性能。     

Prediction of effluent arsenic concentration of wastewater treatment plants using machine learning and kriging-based models

Environmental Science and Pollution Research - This study evaluates the potential of kriging-based (kriging and kriging-logistic) and machine learning models (MARS, GBRT, and ANN) in predicting the...