品红的深度氧化机理研究

选用 2 5 3 7nm的紫外光为激发光源 ,对品红 /过氧化氢体系中的紫外光解离进行了研究 .结果表明 ,该体系中品红的解离近似为表观一级反应 ,解离反应的速率常数为 0 0 386 7s- 1.品红水溶液的脉冲瞬态光谱结果表明 ,品红主要与OH自由基反应而导致脱色 ,其在 5 4 0nm处的脱色与 34 0nm处的瞬态吸收存在很好的相关性 ,品红在5 4 0nm处脱色为一级反应 ,速率常数为 8 1 0× 1 0 5s- 1,34 0nm处新的瞬态物种生成较快而衰减较慢 ,其衰减速率为 5 33× 1 0 3 s- 1.     

臭氧与TiO2/UV协同降解对氯苯酚

利用O3／UV、TiO2／UV和O3／TiO2／UV降解对氯苯酚表明，臭氧与TiO2／UV具有明显的协同作用，如在本实验条件下降解5min后，上述3者对对氯苯酚的去除率分别为55％、10％和77%。O3／TiO2／UV协同作用的本质是由于臭氧能带走二氧化钛光致电子空穴对中的电子，从而产生了更多的羟基自由基，加速了有机物的降解。     

Photodegradation of polychlorinated dibenzo-p-dioxins and dibenzofurans in soil with vegetable oil

GOAL, SCOPE AND BACKGROUND: This study was carried out to investigate the effect of olive oil on the photodegradation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in contaminated sawmill soil. Previous studies had shown that the solubility of PCDD/Fs in olive oil is high and a rapid photodegradation of PCDD/Fs takes place in olive oil when irradiated with ultraviolet (blacklight) lamps. The efficiency of this treatment method was evaluated under more practical conditions. These included the use of sunlight irradiation and a lower-grade olive oil, without a preliminary extraction of soil with olive oil. METHODS: A 1-cm layer of contaminated sawmill soil was blended with 20 weight-% of olive oil and exposed to sunlight for four weeks. In another experiment, a new dose of olive oil was added at the middle of the exposure period. The PCDD/F concentrations of the soils were monitored periodically. RESULTS AND DISCUSSION: A reduction in the concentration of 2,3,7,8-chlorinated PCDD/Fs by 59% and in WHO-TEQ in contaminated sawmill soil by 48% was attained after blending the soil with two doses (20 + 20%) of olive oil and exposing the mixture to sunlight for four weeks. Photodegradation with only one dose of olive oil was less efficient. This suggests that periodical additions of olive oil would be needed to maintain a proper degradation rate. After the oil additions, the WHO-TEQ content of the soil declined with first order reaction half-lives of 19.2 to 19.7 d. The overall half-life during the four-week treatment, however, was 30 d. CONCLUSION: A significant reduction in the PCDD/F concentration of aged sawmill soil can be achieved with a relatively simple olive oil-sunlight treatment. RECOMMENDATIONS AND OUTLOOK: Some theoretical and technological questions need to be solved before using the investigated soil decontamination method in larger-scale applications. The functions of vegetable oils in photodegradation processes should be studied in more detail. The amount of oil that is needed for a proper solubilisation and photodegradation of PCDD/Fs should be minimised. Moreover, special care should be taken to prevent mobilisation of PCDD/Fs to the surrounding environment and to avoid leaving bioavailable residuals of PCDD/Fs in soil.     

紫外光去除水中微量甲苯的研究

紫外光（UV）去除水中微量甲苯（＜10mg/L)可以用一级动力学方程描述。pH为7时，去除速率常数k为0.453h^-1，半衰期为1.53h；在pH为5－9的范围内，速率常数和半衰期变化不大。利用气相色谱－质谱联用仪测定了甲苯的降解产物，讨论了甲苯降解的机理。测定了甲苯降解过程中溶解氧化的变化和pH的作用。     

Ferrioxalate-mediated photodegradation and mineralization of 4-Chlorophenol

INTENTION, GOAL, SCOPE, BACKGROUND: Advanced oxidation processes are powerful methods which are capable of transforming refractory, nonbiodegradable and/or toxic organic compounds into harmless end products such as carbon dioxide and water. However, one commen problem of all advanced oxidation processes is the high demand of electrical energy for ultraviolet lamps, which causes high operational costs. Minimization of the required irradiation time, and therefore the energy consumption, by optimization of other reaction conditions such as catalyst-oxidant type and concentration, pH, temperature, pollutant/oxidant ratio etc., therefore continues to gain importance. OBJECTIVE: The main objective of this study was the minimization of the required irradiation time through optimization of the use of a newly patented catalyst, ferrioxalate, and also to compare the performance of this catalyst with the performance of other AOPs. METHODS: Oxidation of 4-chlorophenol by photo-Fenton process using potassium ferrioxalate as a mediator was studied in a lab scale photoreactor. The influence of parameters such as hydrogen peroxide and ferrioxalate concentrations, initial pH, power-output, oxalate/iron ratio and different iron sources was evaluated. An upflow photoreactor equipped with a 1000 Watt high-pressure mercury vapour lamp and operating in a recirculation mode was used during photodegradation experiments. The extent of the reduction of 4-chlorophenol, Total Organic Carbon and Chemical Oxygen Demand was used to evaluate the photodegradation reaction. RESULTS AND DISCUSSION: The optimum pH range observed was found to be 2.7-3. The efficiency of 4-chlorophenol oxidation increased with increasing concentrations of hydrogen peroxide and ferrioxalate, reaching a plateau after the addition of 10 and 0.072 mM of those reagents, respectively. Using an Oxalate/iron ratio of 12 was 18% less efficient than using a ratio of 3:1. The efficiency increased with increasing radiation power. However, this increase was not linear. The UV/ferrioxalate/H2O2 process, by which complete mineralization of 100 mg l(-1) 4-chlorophenol was achieved in 20 min of total reaction time, was the most efficient process among the alternatives applied. CONCLUSIONS: The use of ferrioxalate as the catalyst was found to be more efficient than the use of Fe(II) and Fe(III) iron species. It was possible to completely mineralize 4-chlorophenol. RECOMMENDATION AND OUTLOOK: The results of this study demonstrate that the ferrioxalate-mediated degradation of 4-chlorophenol requires less irradiation times than other advanced oxidation processes. There are mainly 19 phenol isomers and other toxic and nonbiodegradable organic compounds. We recommend that similar studies should be performed on many such compounds in order to attain a clear understanding of the performance of this catalyst. Because of its light sensitivity, this catalyst should be used immediately after its preparation. The use of low pressure mercury vapour lamps in this process should also be considered, since low power outputs may be enough for the process.     

六氯苯的O3及UV/O3高级氧化降解试验研究

采用O₃、UV/O₃高级氧化法对水中六氯苯（HCB）的降解效果及机理进行了研究，并对结果进行了比较，结果表明，UV本身对HCB的去除率贡献不大，HCB可被O₃、UV/O₃快速降解，即UV＜O₃＜UV/O₃；O₃、UV/O₃作用时，提高体系的初始pH值不利于HCB的降解，在pH＝3，HCB=0.2 mg/L，反应40 min时，HCB的去除可达50%左右，酸性条件下有利于降解反应的进行；无论是O₃单独作用还是UV/O₃联合作用，HCB的降解基本上满足准一级反应动力学规律，如果体系的pH值基本保持恒定，这种规律就更为明显。根据离子色谱(IC)、GC对六氯苯降解中间产物进行了测定，探讨了O₃、UV/O₃降解六氯苯的途径和机理。     

Decolorisation of Acid Blue 74 by ultraviolet/H<Subscript>2</Subscript>O<Subscript>2</Subscript>

The photodegradation of Acid blue 74 in aqueous solution employing a H₂O₂/ultraviolet system in a photochemical reactor was investigated. The kinetics of decolorization were studied by application of a kinetic model. The results show that the reaction of decolorization followed pseudo-first order kinetics. We demonstrate that there is an optimum H₂O₂ concentration, at which the rate of the decolorization reaction is maximum. Irradiation at 253.7 nm of the dye solution in the presence of H₂O₂ results in complete discoloration after ten minutes of treatment.     

乙草胺和丁草胺在土壤中的紫外光化学降解

采用实验室模拟实验研究了水分、pH值和表面活性剂对乙草胺和丁草胺在土壤中的紫外光降解行为的影响。结果表明，在湿度80％的土壤中，丁草胺和乙草胺的光解深度及光解速率均大于无水条件。随土壤pH值的增大，丁草胺在土壤中的光降解速率加快和光解深度加深。低浓度的阴 离子表面活性剂十二烷基苯磺酸钠（DDBS）促进丁草胺在土壤中的光解，使丁草胺在土壤中的光解深度增加。高浓度的DDBS对丁草胺在土壤中的光解有阻碍作用。阳离子表面活性剂十六烷基三甲基溴化铵（HDTMA）对丁草胺在土壤中的光解也有阻碍作用。     

pH校正最小二乘紫外分光光度法同时测定喹啉异喹啉和萘

利用ｐＨ校正最小二乘算法（ｐＨ—ＣＬＳ）对焦化废水中的喹啉、异喹啉、萘三组分进行了同时测定。在２９０～３４０ｎｍ范围内苯酚、三甲基吡啶及苯系物不干优测定。ｐＨ—ＣＬＳ法既可简化分析步骤又可提高准确度。     

A method for calculating the total ozone amount in the clear skies

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