TiO_2/活性炭光催化技术在印染废水深度处理中的应用研究

通过TiO2／活性炭光催化剂的光催化氧化作用,对印染废水的生化处理出水进行深度处理。实验考察了pH值、催化剂负载次数、光照时间、催化剂投加量等因素对处理效果的影响。实验结果表明：催化剂负载次数为4次,光照时间30min,催化剂投加量为3g时,处理效果最佳。此时出水COD达到50mg／L,色度为2,达到印染行业回用水的标准。     

Photocatalytic degradation of p,p′-DDT under UV and visible light using interstitial N-doped TiO2

1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (or p,p′-DDT) is one of the most persistent pesticides. It is resistant to breakdown in nature and cause the water contamination problem. In this work, a major objective was to demonstrate the application of N-doped TiO₂ in degradation and mineralization of the p,p′-DDT under UV and visible light in aqueous solution. The N-doped TiO₂ nanopowders were prepared by a simple modified sol–gel procedure using diethanolamine (DEA) as a nitrogen source. The catalyst characteristics were investigated using XRD, SEM, TEM, and XPS. The adsorption and photocatalytic oxidation of p,p′-DDT using the synthesized N-doped TiO₂ under UV and visible light were conducted in a batch photocatalytic experiment. The kinetics and p,p′-DDT degradation performance of the N-doped TiO₂ were evaluated. Results show that the N-doped TiO₂ can degrade p,p′-DDT effectively under both UV and visible lights. The rate constant of the p,p′-DDT degradation under UV light was only 0.0121 min^?1, whereas the rate constant of the p,p′-DDT degradation under visible light was 0.1282 min^?1. Under visible light, the 100% degradation of p,p′-DDT were obtained from N-doped TiO₂ catalyst. The reaction rate of p,p′-DDT degradation using N-doped TiO₂ under visible light was sixfold higher than that under UV light. According to Langmuir-Hinshelwood model, the adsorption equilibrium constant (K) for the N-doped TiO₂ under visible light was 0.03078 L mg^?1, and the apparent reaction rate constant (k) was 1.3941 mg L^?1-min. Major intermediates detected during the p,p′-DDT degradation were p,p′-DDE, o,p′-DDE, p,p′-DDD and p,p′-DDD. Results from this work can be applied further for the breakdown of p,p′-DDT molecule in the real contaminated water using this technology.     

Synthesis of SnO2 quantum dots mediated by Camellia sinensis shoots for degradation of thiamethoxam

Abstract

A novel method of synthesis of tin dioxide quantum dots employing Camellia sinensis shoots as reducing agent and stabilizer is presented. The quantum dots were characterized by UV spectroscopy, X-Ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy. The crystalline tin dioxide quantum dots with an average size of 4.3?nm were of flake like morphology capped by phenolic compounds of Camellia sinensis. The quantum dots were employed for the photocatalytic degradation of thiamethoxam resulting in 57% degradation within 45 mins.     

Photocatalytic water splitting of ternary graphene-like photocatalyst for the photocatalytic hydrogen production

•The MoS₂/SiC/GO composite has a strong photocatalytic activity than SiC. •The optimal catalyst yielded the highest quantum of 21.69%. •GO acts as a bridge for electron passage in photocatalytic reaction. In recent times, therehas been an increasing demand for energy which has resulted in an increased consumption of fossil fuels thereby posing a number of challenges to the environment. In the course finding possible solutions to this environmental canker, solar photocatalytic water splitting to produce hydrogengas has been identified as one of the most promising methods for generating renewable energy. To retard the recombination of photogenerated carriers and improve the efficiencyof photocatalysis, the present paper reports a facile method called the hydrothermal method, which was used to prepare ternary graphene-like photocatalyst. A “Design Expert” was used to investigate the influence of the loading weight of Mo and GO as well as the temperature of hydrothermal reaction and their interactions on the evolution of hydrogen (H₂) in 4 h. The experimental results showed that the ternary graphene-like photocatalyst has a strong photocatalytic hydrogen production activity compared to that of pure SiC. In particular, the catalyst added 2.5 wt% of GO weight yielded the highest quantum of 21.69 % at 400–700 nm of wavelength. The optimal evolution H₂ in 4 h conditions wasobtained as follows: The loading weight of Mo was 8.19 wt%, the loading weight of GO was 2.02 wt%, the temperature of the hydrothermal reaction was 200.93°C. Under the optimum conditions, the evolution of H₂ in 4 h could reach 4.2030 mL.     

长江水絮凝污泥制备光催化剂及其催化活性

用聚硅硫酸钛絮凝处理长江水,所产生的絮凝污泥经干燥、煅烧处理后制备了具有较高催化活性的复合光催化剂,并用XRD对其进行了表征。考察了絮凝pH值、煅烧温度、絮凝剂投加量和光催化剂投加量等因素对复合光催化剂光催化降解活性艳红K-2BP溶液的影响。结果表明,当絮凝pH值为4,煅烧温度为500℃,絮凝剂投加量为0．2g／L时,制备的复合光催化剂催化活性最佳,光催化降解浓度为25mg／L的活性艳红K-2BP溶液15min后降解率达99．9％,与同等实验条件下P-25的降解效率相当。     

Ag-AgIO3改性BiOI光催化剂湿法脱除气态单质汞

采用沉积沉淀-光还原法制备了不同AgIO₃含量的BiOI光催化剂,利用X射线衍射、N₂吸附-脱附、扫描电子显微镜、X射线光电子能谱、紫外-可见漫反射光谱和电子自旋共振对其物理化学结构进行表征,在光催化反应器上研究了AgIO₃负载量、光照、溶液温度、pH值、SO₂和NO对气态单质汞（Hg⁰）去除性能的影响.结果表明,与BiOI相比,Ag-AgIO₃改性后光催化剂的脱汞性能大幅提高.当AgIO₃负载量为4wt.%时,光催化剂的脱汞效率高达98%.与NO相比,SO₂对脱汞性能的抑制作用更大.由于Ag和AgIO₃在BiOI表面的高度分散性,Ag-AgIO₃（4%） BiOI的可见光吸收性能明显提高.荧光灯辐照与Ag-AgIO₃/BiOI光催化剂协同会产生大量的活性物种.在Ag-AgIO₃/BiOI光催化剂的高效脱汞体系中,超氧阴离子自由基（·O₂^-）为最主要的活性物质,而空穴（h⁺）和羟基自由基（·OH）次之.     

Photocatalytic degradation of Acid Blue 62 over CuO-SnO2 nanocomposite photocatalyst under simulated sunlight

The novel CuO-SnO2 nanocomposite oxide photocatalysts were prepared by simple co-precipitation method, and characterized by X- ray diffraction, transmission electron microscopy, N2 adsorption-desorption measurement and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of CuO-SnO2, evaluated using the photodegradation of Acid Blue 62 as a probe reaction under the irradiation of Xenon light, were also found to be related to the calcination temperature and the molar ratio of Cu to Sn. The maximum photocatalytic activity of the CuO-SnO2 photocatalyst was observed to be calcined at 500~C for 3 h （the molar ratio of Cu to Sn was 1：1） due to the sample with good crystallization and high surface area. It also showed much higher photocatalytic activity in treatment dye wastewater under simulated sunlight irradiation compared to Degussa P25 TiO2.     

二硫化钼基异质结催化剂可见光降解有机污染物的研究进展

光催化是近年来迅速发展的、利用太阳能进行能源转化和环境净化的新技术。二硫化钼具有层状结构,是过渡金属硫族化合物的代表,因具有带隙窄、活性位点多、比表面积大的优点而成为良好的助催化剂,广泛应用于光催化降解有机污染物。介绍了国内外不同类型二硫化钼基异质结催化剂（金属氧化物、铋基材料、银基材料、金属硫化物、石墨氮化碳、氧化石墨烯）的研究现状,对比了二硫化钼基异质结催化剂的制备方式及光催化降解有机污染物的效果,并简述其降解机理。结果表明,二硫化钼的耦合作用可以有效提高基质材料的光催化活性。今后研究将继续围绕开发高效、高稳定性和可回收的二硫化钼基异质结催化剂来展开。

     

Construction of ternary CuO/CuFe2O4/g-C3N4 composite and its enhanced photocatalytic degradation of tetracycline hydrochloride with persulfate under simulated sunlight

In this study, a graphitic carbon nitride（g-C₃N₄） based ternary catalyst Cu O/Cu Fe₂O₄/gC₃N₄（CCCN） is successfully prepared thorough calcination method. After confirming the structure and composition of CCCN, the as-synthesized composites are utilized to activate persulfate（PS） for the degradation of organic contaminant. While using tetracycline hydrochloride（TC） as pollutant surrogate, the effects of initial p H, PS and catalyst ...     

泡沫镍负载纳米ZnO-SnO2光催化降解三氯乙烯

采用比较简单的共沉淀法技术制备了纳米ZnO-SnO2复合氧化物光催化剂,并将其负载在泡沫镍上制成了负载型纳米光催化剂,以三氯乙烯为挥发性有机物的模型反应物,研究了反应气流速、湿度等因素对反应的影响,同时考察了催化剂的失活特征,结果表明该负载型纳米光催化剂具有较高的光催化活性,同时具有较强的抗失活性能,在205h反应中没有出现失活现象．