Photolysis of H_2S with interior microwave discharge electrodeless lamps

The luminescent properties of microwave discharge electrodeless mercury lamp（MDEL-Hg） which was ignited within the resonant cavity and photolysis of hydrogen sulfide with low concentration were studied in this paper.Experiment results indicated that the Interior MDEL-Hg could be made the best of energy utihzation and the efficiency of photolysis of H2S was very significant under the experimental conditions with the initial H2S concentration of 7.9 mg m^-1.With residence time of 1.5 s,the removal efficiency of hydrogen sulfide was 91%,the absolute removal amount（ARA） was 3.24μg s^-1 and the energy consumption was 58.23 mg（kWh）^-1.

The near-infrared spectra and distribution of excited states of electrodeless discharge rubidium vapour lamps

The population ratio between the excited states of rubidium in the electrodeless discharge rubidium vapour lamp is calculated according to the near-infrared spectra in the region of 780-1550 nm. By using a 1529 nm laser, we measure the density of natural rubidium atoms at the 5P3/2 level. The populations of different excited states are then clarified.

Modelling of Ar-Hg Electrodeless Lamps

A self-consistent model of high-frequency electrodeless lamps with internM coils is developed. Radial distributions of the plasma parameters are obtained. Mercury lines with wavelength of 435.8 nm and 365 nm are measured to testify the model. Based on the model, the population of resonance state 63p1 of mercury in dependence on the argon pressure and driving frequency is calculated. It is shown that the population of 63p1 of mercury is larger when the argon pressure is between 26.6 Pa and 53.2 Pa. Meanwhile the driving frequency has little influence on the population of 63P1.

Treatment of simulated wastewater containing Reactive Red 195 by zero-valent iron/activated carbon combined with microwave discharge electrodeless lamp/sodium hypochlorite

A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon （ZVI/AC）, microwave discharge electrodeless lamp/sodium hypochlorite （MDEL/NaCIO） and the combination of ZVI/AC- MDEL/NaCIO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaCIO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaCIO, we found that in the ZVI/AC-MEDL/NaCIO process, ZVI/AC could break the azo bond firstly and then MEDLfNaCIO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency.

Electrical and Optical Characteristics of Electrodeless Lamp

In order to study the methods to enhance the efficacy of electrodeless lamp,volt-ampere characteristics,illuminance and emission spectrum have been investigated in home-built electrodeless lamp experimental system with an electrodeless lamp in shape like QL 85 lamp.The results show that lamp current increases as lamp voltage increases in non-discharge,the current decreases first and then increases as the voltage increases in discharge.The illuminance of electrodeless lamp increases linearly with discharge power increasing,and it decreases linearly with power decreasing.The emission spectrum is different for different bulb and lighting time.The spectrum of Ar 811.5 nm,76.5 nm,750.4 nm and Hg 313.2 nm decrease with lighting time.While the intensity of Hg 407.8 nm increases with lighting time.

Low pressure mercury–argon electrodeless fluorescent lamp simulation using the finite volume method

A finite volume model of a low pressure Ar-Hg electrodeless lamp with external coils is established. The physical configuration is similar to the OSRAM/ENDURA 70 W lamp. A Maxwellian energy distribution is assumed. Two dimensional behaviors of the most important plasma parameters such as the electron density, the electron temperature and the most important mercury states are discussed. Results are in good agreement with former studies and the general understanding in this area. Also, the influence of the argon pressure is studied. Based on the simulation, the population of the main resonance state, Hg （63p1） depends on the argon pressure and the optimized value is about 300 mTorr.

Population Distribution of Excited States in Cs Electrodeless Discharge Lamp

We measure the intensity of fluorescence spectral lines of Cs atoms in an electrodeless discharge lamp from visible light to the near-infrared region of 400-100Ohm. To build an excited state Faraday anomalous dispersion optical filter, the population ratios between the excited states are calculated by rate equations and the spontaneous transition probabilities. The electrodeless discharge lamp with populations in the excited states can be used to realize the frequency stabilization reference for lasers at multiwavelength and the excited state Faraday anomalous dispersion optical filter for submarine communication applications in blue-green wavelengths to simplify the system.

The roles of active species in photo-decomposition of organic compounds by microwave powered electrodeless discharge lamps

Knowledge of the effective radiation spectrum irradiating substrates from microwave powered electrodeless discharge lamps（MEDLs）, and the active species that directly oxidize substrates in the photolytic process, is fragmentary and unclear. In this work, we conducted a comparative study using MEDLs made with quartz envelopes（MEDL-quartz） and with borosilicate Pyrex envelopes（MEDL-Pyrex） targeting the degradation of Rhodamine B（Rh B）via radical-extinguishing tests. We found that UVC/UVB radiation is essential to generate·OH and H2O2 in the MEDL-quartz system. The degradation of Rh B mostly originates from·OH species, which account for a contribution of 53.8%, while the remaining contribution is attributed to oxidation by H2O2 and direct photolysis. This degradation is influenced by several parameters. Acidic and neutral p Hs, but not extreme alkaline p H, benefit the degradation. To ensure a high intensity of UVC/UVB, the optimum ratio of the MEDL volume to the aqueous solution volume（VL/VS） is 0.4. Concentrations of 0.15-0.20 mmol/L of Rh B are suitable to obtain an effective quantum absorbance in the MEDL-quartz system,showing a high decomposition rate of 5.6 × 10^-3（mmol/L）min-1. Moreover, two other substrates, Reactive Brilliant Red X-3B and Safranine T, were tested and found to be efficiently degraded in the MEDL-quartz system.

水溶液中4-氯酚的微波辅助光化学降解

研究了微波辅助无极紫外灯 (MW /UV)光化学降解 4 氯酚 (4CP)模拟废水 ;为了考察溶液中 4CP的降解效果 ,用紫外可见分光光度法 (UV VIS)和离子色谱法 (IC)测定了溶液中 4CP的降解率和Cl-浓度 .结果表明 ,MW /UV体系中 30mg/L 4CP反应 1 2 0min的降解率由紫外 (UV)光解体系的 2 1 5 6 %提高到 5 2 4 0 % .提高溶液的pH值、向体系通入氧气、增强光照度以及外加氧化剂H2 O2 均能增加水溶液中 4CP的降解率 .微波辅助光化学降解

微波辅助光催化降解4-氯酚的研究

采用了一种新的水处理技术微波辅助光催化(MW/UV/P25)降解4-氯酚(4CP)模拟废水。初始质量浓度为30mg/L的4CP在微波光催化下发生了降解,反应120min,4CP的降解率达到82.85%,Cl-质量浓度增加值为7.95mg/L。4CP的降解率与溶液的pH、通气条件、紫外灯光照度等因素有关,外加H2O2氧化剂能够加速4CP的降解。微波辅助光催化降解4CP服从一级反应动力学方程。

无极灯启动特性研究

为了研究提高无极灯光效的方法,本文测量了无极灯启动阶段的电参数和发射光谱,分析了点灯后阻抗、Hg原子光谱强度、Ar原子光谱强度、等离子体参数和放电模式随时间的变化规律。结果表明,在启动阶段,无极灯阻抗发生了升-降-升的变化;Hg原子谱线强度在某稳定位置附近做相对稳定的波动;Ar原子光谱强度迅速下降到某稳定值;电子浓度迅速下降到某稳定值,中能电子温度相对稳定;放电处于H型放电模式。这为进一步设计电子整流器和提高无极灯的光效奠定了基础。

新型微波无极紫外光源用于光化学反应的综合评述

用于光化学反应的光源中,微波无极紫外光源可以完全避免普通紫外光源的一系列问题。由于该类光源没有电极,不会产生像其他放电光源那样由于电极氧化、损耗和封接密封问题引起的发黑现象,而且很少受工作电压、工作频率、工作电流的限制。研究结果表明微波无极紫外光源具有发光强度高,启动快,形状可灵活多变等特性。将微波无极紫外灯取代普通紫外灯,应用于环境治理,能提高处理效果,降低投资和运行成本。

无电极放电灯的新进展

无极放电灯是新型放电灯 ,由于没有电极使该灯具有结构简单、高显色性、高光效和长寿命等特性。近年来对灯的进一步开发使灯应用更加广泛。无电极放电灯将发展成为 2 1世纪新的节能光源。本文主要介绍了无电极放电灯的种类、特性和新的进展。

新型无极LCD平板背光源

为了降低制作成本,提高生产效率,实现液晶显示器在大尺寸品种上的高画质化,文章介绍研制的一种新型等离子体激发发光平板背光源。该电光源无电极,在两片平板玻璃中间充入纯氙气(气压2.67×104Pa),玻璃的外表面上密封一层透明水膜作为导电介质,以1.1mm厚的玻璃板作为介质阻挡层,在高频交变电压的作用下,产生等离子体,激发荧光粉发光。发光亮度可达3000cd/m2,最佳激发频率10.2kHz,启动电压6kV,发光均匀度大于92%;并综合评价了驱动电压、激发频率和样品厚度等因素对背光源发光特性的影响。

微波紫外无极碘灯降解硫化氢气体

采用微波激发方式使无极碘灯发生放电,产生207 nm紫外辐射,并用于降解H2S气体.考察了初始ρ(H2S)、停留时间和微波电源功率等因素对H2S降解的影响.结果表明:H2S在微波无极碘灯停留时间为1.75 s时,其降解率随初始ρ(H2S)的升高而降低.初始ρ(H2S)为57.5 mg/m3时,H2S降解率为20.5%;初始ρ(H2S)为7.3 mg/m3时,H2S降解率可达到64.2%.在保持初始ρ(H2S)及停留时间不变的情况下,H2S降解率随电源功率的增加而提高.H2S经微波碘灯光解后的最终产物含有SO42-.

无极灯系统的建模与分析

作为一种高光效、长寿命电光源,无极灯系统由作为供电电源的电子镇流器和发光泡体组成,电子镇流器的输出特性和发光泡体的阻抗特性之间存在着复杂的相互关系,共同决定了无极灯系统的启动速度和发光效率等性能。为了对无极灯系统进行建模与分析,本文首先搭建实验平台,对2.65MHz下发光泡体的阻抗特性进行了测量;其次,本文基于无极灯电子镇流器的电路拓扑,结合发光泡体的阻抗,通过数值拟合建立了电子镇流器串联谐振并联负载输出级参数与输出电压之间的关联数学模型,并对电子镇流器输出级的基本状态变量进行了分析,联立相应的边界条件得到了电子镇流器输出电压和电流的解析表达;最后,对电子镇流器输出电压进行了数值计算、Pspice仿真和实验验证,三者结果基本吻合,验证了所建系统模型和分析结果的准确性。

微波无极紫外光对自来水中微生物的灭活作用

选取大肠杆菌和枯草芽孢杆菌分别代表自来水中易被灭活和不易被灭活的微生物,研究了微波无极紫外光最佳杀菌效果的极限浊度和照射时间。在此条件下,考察了自来水中大肠杆菌和枯草芽孢杆菌杀灭情况,并与普通中压汞灯进行比较。结果表明:最佳照射时间为210s,微波无极紫外光杀菌率高达99.92%;为了获得最佳的杀菌效果,原水浊度应<8NTU,杀菌的极限浊度为40NTU;微波无极紫外光在180s时,对大肠杆菌的杀菌率达到100%;在300s时,对枯草芽孢杆菌的杀菌率达到100%,明显高于普通中压汞灯产生的紫外线杀菌效果。

微波增强TiO2光催化降解染料和水杨酸

Photodegradation of malachite green (MG) as the model molecule with TiO2 catalyst by microwave discharge electrodeless lamps (MDELs) was investigated.The effects of different parameters in photodegradation of MG,such as MDEL shape,microwave power,initial solution concentration,and catalyst dosage were discussed.Additionally,the photodegradation of congo red,acid black,acid fuchsine and salicylic acid with anatase TiO2 catalyst were investigated under the optimal reaction condition.The results showed that the MDEL is a new treatment method for enhancing photodegradation of organic contaminants with TiO2 catalyst.

无极灯稳定性研究

为了研究提高无极灯光效的途径,本文通过测量无极灯的放电电压、电流、功率和光照度,计算了无极灯的阻抗变化。结果表明,放电电压先降后升而后趋于稳定;放电电流先升后降然后趋于稳定;无极灯阻抗先迅速下降而后小幅升高再趋于稳定;光照度先升后降而后趋于稳定。迅速稳定无极灯泡体内的等离子体浓度才能提高无极灯的稳定性。

微波辅助光催化降解氯酚类污染物的研究

研究了溶液中4-氯酚(4CP)、2-氯酚(2CP)、4-氯-3-甲基酚(4C3MP)、2,4-二氯酚(2,4-DCP)、2,4,6-三氯酚(2,4,6-TCP)和五氯酚(PCP)的微波辅助光催化降解(MW/PCO)。结果表明,6种氯酚(CPs)光降解速率与分子中Cl原子取代的数目、位置等分子结构性质有关,单氯酚比多取代氯酚易光解。MW/PCO降解4CP的主要中间产物为苯酚、氯苯、对苯醌、对苯二酚等,降解PCP的主要中间产物为2,3,5,6-四氯对苯醌、2,3,4,6-四氯对苯二酚、四氯酚。CPs降解的机制是紫外光降解和羟基自由基(.OH)亲电子加成脱氯过程。