沿面脉冲流光放电等离子体降解水中的氟磷酸二异丙酯

采用沿面流光放电等离子体考察了水中G类毒剂模拟剂氟磷酸二异丙酯(DFP)的降解效果及影响因素。结果表明,高压脉冲沿面流光放电等离子体可以有效降解水中的DFP。DFP的去除率随放电电压、放电频率和放电电极数目的增加而升高,随放电间距的增加而降低,水样初始DFP含量对其去除率的影响不大。当放电电压为20kV、放电频率为1 000 Hz、放电间距为5 mm、放电电极数目为9时,初始质量浓度为65~126.5 mg/L的DFP溶液经60min的放电处理后,DFP去除率可达96%以上。反应动力学分析结果表明,等离子体降解DFP的反应符合1级反应动力学特征,其反应速率常数约为0.055min-1。     

介质阻挡放电等离子体反应器降解盐酸四环素

采用介质阻挡放电等离子体反应器降解盐酸四环素(TC),研究了输入功率、放电间距、气体流量、初始浓度等参数对盐酸四环素降解效果的影响,结果表明当输入功率为1.3W,放电间距为2.5 mm,气体流量为150ml·min~(-1),初始浓度为100 mg·L~(-1)时降解效果最好,放电处理30 min盐酸四环素的降解率达到92%。动力学研究表明盐酸四环素的降解过程符合拟二级动力学方程。检测了降解过程中生成的中间产物,提出了盐酸四环素的降解路径与机理。     

Ti/IrO2-Ta2O5阳极电催化氧化法处理含酚废水

采用新型的钛基金属氧化物涂层电极(Ti/IrO2–Ta2O5)作为阳极,石墨作为阴极对含酚模拟废水进行电催化氧化降解实验。当电解条件为电压U=9.0V;电流I=2.5A;板间距d=3.0cm;电解质NaCl浓度20.0g·L-1,初始pH=7.0时,初始浓度为1000mg·L-1苯酚模拟废水电解90min后,处理效果较理想,其中电流和电解质浓度为主要影响因子。Ti/IrO2–Ta2O5阳极电催化氧化降解苯酚的过程符合一级反应动力学。     

过氧化氢对绕线虫的灭活效果和动力学

以分离自饮用水的绕线虫为研究对象,探讨了过氧化氢对绕线虫的灭活效果和动力学.结果表明,绕线虫对过氧化氢灭活的抵抗力很强,在过氧化氢质量浓度201 mg·L-1和接触时间120 min的条件下绕线虫的灭活率仅达67%;在过氧化氢质量浓度201mg·L-1和接触时间120min范围内,过氧化氢对绕线虫的灭活动力学为1级反应;此外,过氧化氢质量浓度与绕线虫灭活反应速率常数之间存在正的线性相关关系.     

介质阻挡放电等离子体对茜素红溶液的降解

利用介质阻挡放电等离子体法对染料茜素红溶液进行降解。考察了放电间距、输入电压及溶液pH值对茜素红降解效果的影响,并通过测定放电过程溶液中活性粒子O₃的浓度,探讨了促使茜素红降解的主要因素。结果表明,高压电极与液面间距为8 mm、输入电压为8 kV时,降解效果较好。其中弱碱性环境下（pH=8.4）降解效果最好,40 min后茜素红浓度降为0.26 mg·L^-1,在弱酸性环境（pH=5.8）中处理45 min后,茜素红浓度为1.61 mg·L^-1,而在中性环境（pH=7.0）中降解效果较差,处理45 min后茜素红残留浓度为5.70 mg·L^-1。溶液中的O₃是推动氧化反应进行的主要因素。     

介质阻挡放电降解废气中萘的实验研究

采用介质阻挡放电对模拟废气中萘的降解进行了研究,深入分析了放电特性和萘的降解特性。研究结果表明:介质阻挡放电过程产生了90 ns脉宽的脉冲电流。放电电压的增加提高了能量密度,从而促进了萘的降解。在7 k V的放电电压下,能量密度达到了236.4 J·L-1,此时萘的降解效率为94.1%。而随着放电电压的增加,萘的降解产物COx的选择率却有所下降。在相同的能量密度下,低放电频率、窄放电气隙有助于萘的降解。介质阻挡放电过程中仅产生6μL·L-1左右的NOx,而生成了500μL·L-1以上的O3。另外,萘的降解过程还产生了萘醌、脂肪族化合物和短链烃等副产物,这表明氧自由基在萘的降解过程中起到了重要的作用。     

电化学氧化降解对氯苯酚动力学及其影响因素的研究

采用自制电化学反应器对模拟对氯苯酚(4-CP)废水进行了电化学氧化降解的研究,考察了支持电解质的浓度、外加电压、pH值、对氯苯酚初始浓度及NaCl电解质等对4-CP降解的影响,得出了对氯苯酚的电化学氧化降解是符合准一级反应动力学模型,且反应速率常数主要受外加电压的影响,与外加电压的2.6次方成线性关系,当NaCl为电解质时,以间接反应为主,反应速率常数可提高一个数量级.     

辉光放电电解等离子体降解模拟染料废水碱性紫16的研究

用辉光放电电解等离子体(GDEP)技术对模拟染料废水碱性紫16的降解过程进行了研究。通过对电流电压曲线分析,阐述了各阶段变化趋势成因,确定产生辉光放电电压为450 V左右。采用紫外分光光度法对不同降解时间下碱性紫16脱色率进行了分析,结果表明,在600 V电压下,20 mg·L~(-1)碱性紫16可在40 min时脱色率达97.8%,整个降解过程符合一级动力学反应的特征。加入2 g·L~(-1)FeCl2后,促进了HO·的生成速度,使100 mg·L~(-1)碱性紫16在40 min时脱色率达到95.4%。碱性紫16在GDEP降解下,经共轭结构的破坏,助色团最终被矿化为CO2和H2O,其中HO·起到了关键性作用。     

电化学氧化法降解内分泌干扰物阿特拉津的研究

采用以铁板作阴、阳极,活性炭作第三维填料电极的三维电极电化学氧化法降解水中阿特拉津.考察了输入电流,极板间距、初始pH、活性炭投加量和反应时间对阿特拉津降解效果的影响,并对阿特拉津的降解动力学规律进行了初步探讨.结果表明,三维电极电化学氧化法能有效地降解阿特拉津,最佳工艺条件为:输入电流为10mA、极板间 距为4 cm、初始pH为4、反应时间120min、活性炭投加量为10g·L-1.在此条件下,初始浓度为15mg·L-1的阿特拉津 降解效率可高达90.4%.阿特拉津的降解过程遵循一级反应动力学规律,降解速率常数与阿特拉津的初始浓度无关,降解速率方程为:C=C0e-0.0286t.     

Al~(3+)/UV催化臭氧去除偶氮二异丁腈废水中CN~-的研究

研究Al3+/UV催化臭氧对偶氮二异丁腈废水中CN-的降解特性。分析了pH、Al3+投加量和O3浓度对Al3+/UV催化臭氧降解CN-的影响。探讨Al3+/UV催化臭氧工艺中光催化反应动力学特征。结果表明,当pH值为9.0、Al3+投加量为0.61 g·L-1和气相臭氧质量浓度为50~55 mg·L-1时,偶氮二异丁腈废水中CN-的降解效果较好。Al3+/UV催化臭氧工艺降解腈纶废水的反应符合类一级动力学反应,偶氮二异丁腈废水中的初始CN-值在600~1500 mg·L-1时,一级反应速率常数为0.03011~0.00651 min-1。所需水力停留时间为240 mim。     

Fenton试剂与双频道超声波协同降解溶液中对氯苯酚的研究

4-Chlorophenol (4-CP) solution was treated by dual-frequency ultrasound in conjunction with Fenton reagent, and obvious improvement in the 4-CP degradation rate was observed in this advanced oxidation process.Experimental results showed that ultrasonic intensity, saturating gas and pH value affected greatly the 4-CP removal rate. Among four different saturating gases (Ar, 02, air and N2), 4-CP degradation with Ar-saturated solution was the best. However, in the view of practical wastewater treatment, using oxygen as the saturating gas would be more economical. The addition of Fenton reagent followed the first-order kinetics and increased the 4-CP degradation rate.The 4-CP removal rate increased by around 126% within 15 rain treatment. The synergetic effect of dual-frequency ultrasound with Fenton reagent on 4-CP degradation was obviously observed.     

高压脉冲放电等离子体降解苯酚废水

考察了多种因素对高压脉冲放电低温等离子体降解水中苯酚效果的影响。降低放电电极直径、放电距离、废水的电导率和提高废水的pH值以及向废水中通气体和加入硫酸亚铁等均可提高废水中苯酚的降解速率 ,而加入碳酸钠则会降低苯酚的降解速率。初始质量浓度为 10 0mg/L的苯酚废水经放电处理 180min后降解率达 5 0 9%。     

碳基含铁催化剂催化过氧化氢氧化去除对氯苯酚的试验研究

为了考察自研发的一种低成本、制作简便的碳基含铁新型催化剂(简称HACO-P型)的催化氧化性能,以对氯苯酚(4-CP)为对象,研究其催化H2O2降解水中4-CP的效果及影响因素.对HACO-P进行形貌表征,结果表明其表面多孔、具有巨大比表面积.单独考察了HACO-P对4-CP的吸附性能并进行了等温线拟合,发现其最大吸附容...     

高压脉冲液相放电降解水中邻氯苯酚

研究了高压脉冲液相放电降解水中邻氯苯酚的特性脉冲峰压的升高、电极距离的缩短、脉冲频率的加大均使邻氯苯酚的降解速率增加.在脉冲峰压为30 kV、电极距离为2 cm、脉冲频率为150 Hz条件下,o-CP的降解率约为98.7%.较高输入电压下,溶液初始离子含量的增加,会使放电形式由火花放电→流柱放电→电晕放电转变.在火花放电和流柱放电条件下,邻氯苯酚降解率无明显变化,但在电晕放电时,降解率有所降低.邻氯苯酚受羟基的攻击,生成2-氯-对苯二酚,并进一步被氧化生成2-氯-1,4-对苯醌,2-氯-1,4-对苯醌开环后,进一步被氧化,自由基最终生成丙酸、草酸、乙酸以及甲酸等低分子有机酸.     

Degradation characteristics of toxic contaminant with modified activated carbons in aqueous pulsed discharge plasma process

Activated carbons (ACs) with different textural and surface chemistry properties obtained by HNO₃ oxidation, N₂-thermal treatment, and aqueous non-thermal plasma treatment were studied to analyze their behaviors in degradation of toxic organic pollutant parachlorophenol (4-CP) by the pulsed discharge plasma process in aqueous solution. N₂-heated AC in the 50-110 μm diameter range with a dosage of 0.5 g l⁻¹ under any solution pH had a remarkable promoting effect on 4-CP degradation, as well as an obvious enhancement in energy efficiency for 4-CP removal. Chemical and physical actions induced by pulsed discharge non-thermal plasma (PDP) pose little negative impact on catalytic ability of plasma-treated AC. From mathematical modeling on synergic degradation of 4-CP on AC surface, N₂-heated AC had a strong adsorption ability of 4-CP, including high catalytic activities for H₂O₂ and O₃ decompositions on AC surface, resulting in more amounts of highly reactive species formed, especially ^·OH radical. This would enhance degradation rate and PDP energy efficiency for 4-CP removal, and simultaneously, the AC as catalyst in PDP process was regenerated.     

High-voltage surge protection by a varistor-filled air gap

The electric discharge across a varistor granule filled air gap under a fast-rising voltage pulse was investigated for surge protection applications. The effects of temperature and pressure on the arc and the electrical conduction were analyzed by the characteristic changes in voltage waveforms triggered by a fast-rising high voltage pulse. In addition to the gap size, experimental results show that competing mechanisms among arc conduction, conduction through the varistor granule network, thermionic emission from Joule heating at granule-to-granule contact points, and the magnitude of the switching voltage dictate the maximum surge protection voltage for the filled air gap. Experimental evidence indicated that accumulated degradation was created at small contact points between varistor granules by repetitive assaults from longer duration, high voltage pulses. The uniqueness of using varistor over other dielectric granules in an air gap for surge protection is identified and discussed.     

UVA-LED assisted persulfate/nZVI and hydrogen peroxide/nZVI for degrading 4-chlorophenol in aqueous solutions

Photocatalytic degradation of 4-chlrophenol (4-CP) using UVA-LED assisted persulfate and hydrogen peroxide activated by the nZVI (Nano Zero Valent Iron) in a batch photocatalytic reactor was investigated. The reaction involved a lab-scale photoreactor irradiated with UVA-LED light emitted at 390 nm. The efficiency of the reaction was evaluted in terms of 4-CP degradation and mineralization degree at different pH of solution, initial concentrations of nZVI, persulfate, hydrogen peroxide and 4-CP. In UVA-LED/H₂O₂/nZVI process, complete degradation of 4-CP (>99%) and 75% mineralization was achieved at pH of 3, hydrogen peroxide concentration of 0.75 mM, nZVI dosage of 1mM and initial 4-CP concentration of 25mg/L at the reaction time of 30 min. The optimum conditions obtained for the best 4-CP degradation rate were at an initial concentration of 25mg/l, persulfate concentration of 1.5mM, nZVI dosage of 1mM, pH of 3 and reaction time of 120min for UVA-LED/persulfate/nZVI process. It was also observed that the 4-CP degradation rate is dependent on initial 4-CP concentrations for both processes. The pseudo-first-order kinetic constant at 25mg/L initial concentration of 4-CP was found to be 1.4×10^?1 and 3.8×10^?2 in UVA-LED/H₂O₂/nZVI and UVA-LED/persulfate/nZVI processes, respectively. Briefly, the UVA-LED/H₂O₂/nZVI process enhanced the degradation rate of 4-CP by 3.67-times in comparison to UVA-LED/persulfate/nZVI process at 30min contact time, which serves as a new and feasible approach for the degradation of 4-CP as well as other organic contaminants containing wastewater.     

高压脉冲介质阻挡放电降解土壤中芘的研究

针对我国土壤多环芳烃的污染问题,通过自研的介质阻挡脉冲反应器处理土壤中的芘,研究了放电电压、放电频率、土壤湿度、土壤厚度、空气流速和土壤pH等条件对降解效果的影响。结果表明,随着放电电压和放电频率增加,芘的降解率提高,空气流速和土壤湿度在适宜的范围内,有利于芘的降解,增加土壤厚度和降低pH会降低芘的降解率。最适降解条件为：放电电压12.6 kV、放电频率1.0 kHz、土壤湿度3.0%、土壤厚度1 mm、空气流速2 L/min、土壤pH≥7,芘的降解率为97.04%。通过HPLC-MS和FT-IR分析,间接证明放电产生的活性物质O₃、·OH、NO _x 等导致了芘的降解,提出了芘可能的降解途径。     

高压脉冲介质阻挡放电降解土壤中芘的研究

针对我国土壤多环芳烃的污染问题,通过自研的介质阻挡脉冲反应器处理土壤中的芘,研究了放电电压、放电频率、土壤湿度、土壤厚度、空气流速和土壤pH等条件对降解效果的影响。结果表明,随着放电电压和放电频率增加,芘的降解率提高,空气流速和土壤湿度在适宜的范围内,有利于芘的降解,增加土壤厚度和降低pH会降低芘的降解率。最适降解条件为：放电电压12.6 kV、放电频率1.0 kHz、土壤湿度3.0%、土壤厚度1 mm、空气流速2 L/min、土壤pH≥7,芘的降解率为97.04%。通过HPLC-MS和FT-IR分析,间接证明放电产生的活性物质O₃、·OH、NO _x 等导致了芘的降解,提出了芘可能的降解途径。     

Reductive/oxidative treatment with superior performance relative to oxidative treatment during the degradation of 4-chlorophenol

This study obtained information on the effectiveness of the photo-assisted Fenton oxidation of 4-chlorophenol (4-CP) combined with zero-valent pretreatment. The kinetic rate parameters of the process as well as the operating conditions were determined. Homogeneous photo-assisted Fenton enhanced processes lead to 33% mineralization of 4-chlorophenol (1.25 mM) in solutions containing Fe-ions (2–10 mg/l) and H₂O₂ (10 mM) within 2 h under visible light irradiation. When this solution was pretreated with zero-valent Fe (14 g/70 ml) in Ar atmosphere, the mineralization attained levels of >80% after the second stage photo-assisted Fenton process. Intermediates that could be effectively degraded by photo-Fenton reactions were not attained in the absence of zero-valent Fe pretreatment. The pretreatment by zero-valent Fe under light lead to about 70% of the stoichiometric amount of chloride contained in 4-CP. Partial recovery of chloride ions indicated the formation of chloro-intermediates. These intermediates were experimentally detected by high-pressure liquid chromatograph (HPLC)–MS and the most important intermediates were identified. Fenton photo-assisted processes were effective employing very low concentrations of Fe²⁺(2–5 mg/l) after the pretreatment stage that do not need to be separated after the 4-CP degradation process. This is important for the practical application of the novel combined heterogeneous–homogeneous process. Evidence for the stable catalytic performance of the coupled process to degrade 4-CP is presented. The effect on the 4-CP degradation of Fe-ion, H₂O₂, 4-CP concentration and gas atmosphere was systematically investigated. The activation energy (E_a) of 2.66 kJ/mol was found for the abatement of 4-CP.