等离子体发生区工作时发射特定光谱的研究

介绍了2种不同等离子体发生区和不同测量距离对等离子体发生区沿面蓝光中紫外光的波长和相对光强的影响,所测的臭氧发生量大的等离子体发生区的紫外光的相对光强高,测量距离与相对光强呈指数关系,并且等离子体发生区沿面蓝光具有光催化作用.     

脉冲放电等离子体-催化耦合降解室内甲醛的研究

利用脉冲放电等离子体-催化耦合技术,进行模拟室内空气循环降解甲醛的实验,对比了3种净化方式(紫外光催化、等离子体单独作用与等离子体-催化耦合)的甲醛降解效果,并考察了中心电极的极性、催化剂活性炭板与中心电极的距离对甲醛降解效果的影响.结果表明,相对单独的紫外光催化和等离子体作用而言,等离子体-催化耦合多重功效结合的甲醛降解效果更好,降解速率也更快;中心电极为正极的电场的甲醛降解效果优于中心电极为负极的电场;随着催化剂活性炭板与中心电极距离的不断扩大,直至板移动至电场外部的过程中,甲醛的降解率表现为先上升后下降的趋势,催化剂活性炭板与中心电极的距离存在一个最佳值,本研究的最佳距离为15mm.     

等离子体联合紫外光催化净化有机废气关键技术分析

等离子体-紫外光催化联合技术是一种先进的有机废气治理技术。它解决了单一等离子体技术产率低、能量利用率低和应用条件高的缺点,在环境治理领域具有广阔的应用前景。阐述了3种不同类型的等离子体-紫外光催化反应器。并且对等离子体和紫外光催化处理VOCs的机理,以及2种技术的协同净化机制进行了分析。该技术对喷涂厂废气的净化效果例证了其在实际应用中的可行性。最后,探讨了这一技术存在的问题,以及展望了未来的发展方向。     

新型无极紫外灯的光氧化性能研究

本实验对新型无极紫外灯的发射光谱、不同波长光线在溶液中的传播、·OH和O3的生成量、活性艳红X-3B溶液的降解情况进行了测定,并与普通中压汞灯进行了比较.结果表明,无极紫外灯在紫外区光强约为相近功率的普通中压汞灯的20倍;在溶液中紫外光比可见光更易被吸收;·OH生成与溶液对短波长光子的吸收存在对应关系,本实验中无极紫外灯的最大氧化距离约为6 cm;O3的生成量随着空气曝气量或254 nm处的光强的增大呈指数增加;降解活性艳红X-3B溶液的过程符合负一级动力学关系,降解效果明显好于普通中压汞灯,并且证明了无极紫外灯与生成的臭氧在活性艳红X-3B的降解过程中存在协同作用.     

非平衡等离子体降解废水中有机污染物研究进展

非平衡等离子体废水处理技术是以高活性粒子氧化为主,协同紫外光降解和液电空穴效应等于一体的高级氧化技术,极具发展前景。本文简述其技术原理,对比了不同结构反应器的优缺点,评述了等离子体与其他高级氧化技术协同作用在废水处理方面的应用,提出了其有待解决的问题及发展方向,以期为研发与应用起到借鉴作用。     

柴外分光光度法测定水中的煤焦油

煤焦油含有一系列芳烃,它们有包含在不饱和键内的π键电子,且分子中π键与相间的π键构成π—π键共轭体系。生成大π键后,各能级间的距离较近,价电子更易激发,产生π—π~*跃迁,并在紫外光区产生特征吸收。我们通过近年来试验和实际测量认为用商品二氯甲烷直接萃取水中煤焦油,然后用紫外分光光度计来相应地测定饮用水或污水中微量煤焦油含量收     

等离子体与光催化复合空气净化技术研究

尝试了一种新的等离子体-光催化复合方式进行空气净化,研究表明该种复合方式具有较显著的协同促进效应,通过改变等离子体发生单元与光催化单元的距离以及在两者之间放置网状物,可消除等离子体单元产生的负电荷对光催化单元的不利影响,进一步提高其复合效应.还对这一复合方式产生协同效应的机理进行了分析.     

紫外光协助高锰酸钾降解四环素的研究

高锰酸钾氧化法在实际水处理中得到了一定的应用,但对有机污染物的去除和降解能力相对有限,为此提出了以外加紫外光照射协助高锰酸钾氧化的方法。以四环素作为模型污染物,考察了四环素浓度、高锰酸钾浓度、反应时间、初始pH条件和不同紫外光照射等的影响。结果表明,高锰酸钾能够氧化并去除四环素,紫外光照射明显提高了高锰酸钾对四环素的降解效果,并且254 nm紫外光照射对降解的促进作用远大于365 nm紫外光。在所考察的pH范围内,无论紫外光照射与否,高锰酸钾在酸性条件下的降解效率最高,中性条件较高,碱性条件次之。     

大尺寸大孔径TiO2/SiO2光催化剂的制备及甲醛去除研究

以大孔径SiO2为载体,通过钛酸丁酯溶液的浸渍、原位水解以及高温煅烧制备出大尺寸、大孔径的TiO2/SiO2光催化剂。利用自制空气净化装置对室内甲醛的清除进行研究,分别考察了TiO2的百分含量、紫外光光强、温度、湿度和空气流量等不同条件下TiO2/SiO2光催化剂对除去甲醛效率的影响。结果表明,反应温度从10～50℃依...     

紫外光(UV)光解油田采出水中多环芳烃

为了探讨紫外光光解人工模拟油田采出水中多环芳烃的降解效率,利用自制反应装置对油田采出水中多环芳烃(PAHs)的紫外光光解做了一个初步研究。研究结果证明,紫外光光解对油田采出水中的多环芳烃萘和芴有显著的降解能力。实验室的测试表明,与紫外UVA(365 nm)、UVB(308 nm)的光照相比,紫外UVC(254 nm)在光照60 min的条件下,2种多环芳烃各自的去除率都近似达到了99%。可见,在光解效力和暴露时间两方面,紫外UVC对采出水中萘和芴的去除具有相对稳定和比较高的效率。     

光纤传导可见光降解亚甲基蓝

针对浓度大、色度高的印染废水难以处理的情况,选用加入光纤的光催化体系进行研究。采用溶胶凝胶法制备了Ag+/TiO2粉体光催化剂,用固体紫外可见光谱、X射线衍射对其进行表征。选用亚甲基蓝溶液作为目标降解物,评价了Ag+/TiO2在可见光下的光催化活性。分别考察了加入石英芯侧光光纤与塑料侧光光纤反应体系下,催化剂量、光纤数量、光照强度和pH值等因素对亚甲基蓝降解实验的影响。结果表明,选用20 mg/L的亚甲基蓝,采用催化剂量为11.67 g/L,500根侧光光纤,300 W的外部光源,pH值约为11时,光催化降解效果最佳,均能达到90%以上。     

Comparison of photochemical behavior of various humic substances in water: II. Photosensitized oxygenations

The photochemical oxygenation of 2,5-dimethylfuran (DMF) in water was studied under a variety of reaction conditions employing various humic substances as photosensitizers. As predicted by theory, the reactions at low DMF concentrations were first order with respect to DMF, and the reaction rate constants were directly proportional to the average light intensity and to the concentration of humic substance. The rate of oxygenation photosensitized by the humic matter from a river was independent of hydrogen ion activity in the pH 5 to 9 range. Wavelength studies indicate that oxygenations photosensitized by humic substances are induced by ultraviolet and blue radiation. Rate constants computed for this photosensitized reaction in sunlight were in close agreement with experimental values. Calculations also show that the ratio of the sunlight rate constants to total visible solar irradiance (400 to 700 nm) is approximately constant. Therefore, it may be possible to calibrate rate constants for photosensitized reactions in terms of commonly measured units of visible light intensity such as foot candles.     

H4SiW12O40/TiO2/beads光催化降解亚甲基蓝的研究

以钛酸四丁酯为原料,空心微珠为载体,采用溶胶-凝胶法制备TiO2/beads光催化剂载体,然后浸渍法制备出H4SiW12O40/TiO2/beads表面负载修饰型复合光催化剂,并运用SEM、XRD、FT-IR和DRS对催化剂进行表征和分析。研究了H4SiW12O40/TiO2/beads对亚甲基蓝降解的光催化活性,考察了光强度、pH值、曝气量、底物浓度和催化剂用量等对催化效率的影响。实验结果表明,在中性条件下,H4SiW12O40/TiO2/beads催化剂的投加量为0.25 g/L,浓度为7.5 mg/L的亚甲基蓝溶液在250 W的紫外灯和600 W的可见光灯下光照60 min降解率分别可达到94.5%和55%。     

大尺寸大孔径TiO_2/SiO_2光催化剂的制备及甲醛去除研究

以大孔径SiO2为载体,通过钛酸丁酯溶液的浸渍、原位水解以及高温煅烧制备出大尺寸、大孔径的TiO2/SiO2光催化剂。利用自制空气净化装置对室内甲醛的清除进行研究,分别考察了TiO2的百分含量、紫外光光强、温度、湿度和空气流量等不同条件下TiO2/SiO2光催化剂对除去甲醛效率的影响。结果表明,反应温度从10～50℃依次升高,去除率逐渐下降。在相对湿度为50%,TiO2负载率为55.6%,流量为8 m3/h时,甲醛的最佳除去率达96.5%;经过7周时间的考察,发现TiO2/SiO2光催化剂的催化活性没有明显的下降。     

Phototransformation of herbicide metsulfuron methyl

Phototransformation of the herbicide metsulfuron methyl was investigated on glass surface under sunlight and ultraviolet (UV) light and compared with dark condition. The half-lives of metsulfuron methyl under UV light and sunlight were found to be 0.5 and 7.8 days respectively. Rate of phototransformation followed first order kinetics with significant correlation coefficient. The major photoproducts were identified as methyl-2-sulfonyl-amino-benzoate, 2-amino-6-methoxy-4-methyltriazine and saccharin (O-sulfobenzoimide). Various metabolites from this study were identified by high performance liquid chromatography (HPLC). Authentic samples required for HPLC comparison were prepared in laboratory and characterized on the basis of nuclear magnetic resonance (NMR) and infra red (IR) spectral data. These metabolites were also identified from metsulfuron methyl treated wheat field soil.     

掺碘二氧化钛薄膜自组装制备、表征及光催化性能

通过自组装技术在低温液相反应体系中制备出大尺寸纳米二氧化钛及其掺碘薄膜。使用XRD、TEM、荧光发射光谱仪、激光拉曼光谱仪等手段对样品进行表征,发现掺I^5＋后的二氧化钛薄膜在可见光区也表现出明显的响应,而且合成的I^5＋／TiO2纳米薄膜在TEMggNT其晶型显示为金红石型,并且碘掺杂后样品的拉曼光谱强度减弱,峰位蓝移且宽化。掺杂I^5＋原溶液浓度为2mmol／L时,其可见光下光催化效果最优,5h后降解率可达到95％,较未掺杂的TiO2纳米薄膜提高了40％,I^5＋掺杂明显提高了TiO2对甲基橙溶液的光催化降解效率。     

H4SiW12O40/TiO2/beads光催化降解亚甲基蓝的研究

以钛酸四丁酯为原料,空心微珠为载体,采用溶胶凝胶法制备TiO₂/beads光催化剂载体,然后浸渍法制备出H₄SiW₁₂O₄₀/TiO₂/beads表面负载修饰型复合光催化剂,并运用SEM、XRD、FT-IR和DRS对催化剂进行表征和分析。研究了H₄SiW₁₂O₄₀/TiO₂/beads对亚甲基蓝降解的光催化活性,考察了光强度、pH值、曝气量、底物浓度和催化剂用量等对催化效率的影响。实验结果表明,在中性条件下,H₄SiW₁₂O₄₀/TiO₂/beads催化剂的投加量为0.25 g/L,浓度为7.5 mg/L的亚甲基蓝溶液在250 W的紫外灯和600 W的可见光灯下光照60 min降解率分别可达到94.5%和55%。     

Solar photocatalytic decolorization of methylene blue in water

In this study, a photocatalytic decolorization system equipped with immobilized TiO2 and illuminated by solar light was used to remove the color of wastewater. To examine the decoloring efficiency of this system, photocatalytic decolorization of an organic dye such as methylene blue was studied as an example. The effects of light source, pH, as well as the initial concentration of dye were also investigated. It was observed that the solution of methylene blue could be almost completely decolorized by the solar light/TiO2 film process while there was about 50% color remaining with solar irradiation only. In addition, it was found that the decoloring efficiency of solution was higher with solar light irradiation than with artificial UV light irradiation, even though the artificial UV light source supplied higher UV intensity at 254 nm. The color removal rate of methylene blue with solar light irradiation was almost twice that of artificial UV light irradiation. This phenomena was mainly attributed to that some visible light range of solar light was useful for exciting the methylene blue molecules adsorbed on TiO2 film, leading to a photosensitization process undergoing and decoloring efficiency promoted. This solar-assisted photocatalytic device showed potential application for decoloring organic dyes in wastewater.     

有机酚及光照强度对水网藻的胁迫效应研究

研究了富营养化水体中有机酚及光照强度等对修复生物的影响。结果表明,充足的光照可以有效地提高水网藻对水中有机酚的抗性、加速苯酚的降解、增加活性氧产率、降低细胞质膜的电解质透性并且增强多糖的代谢;而高于50 mg/L的苯酚会导致水网藻细胞质膜电解质透性显著增强、多糖含量降低,进而对水网藻产生不可逆性损伤。