水蒸气电晕放电下的烟气脱硫效果

采用多针-板式电极,在70 m³/h烟气流量范围内,研究了水蒸气浓度、烟气流量、电场强度等因素对不饱和水蒸气正直流电晕放电烟气脱硫率的影响以及水蒸气电晕放电对脉冲放电烟气脱硫率的提高.研究结果表明,实验范围内,按照NH₃∶SO₂摩尔比为2∶1添加NH3的条件下,增加水蒸气流量、增强电场强度、减少烟气流量,烟气脱硫率能提高10%,达到60%左右.同时,水蒸气电晕放电能使脉冲放电的烟气脱硫率提高5%左右,达到90%以上.     

德州市夏季臭氧敏感性特征及减排方案

近年来德州市臭氧污染频发,2018年夏季（6~8月）,德州市发生了严重臭氧污染事件,臭氧日最大8 h浓度值超标天数达60 d,超标率65%,3个月平均值为176 μg ·m^-3,最高达262 μg ·m^-3.本研究利用WRF-CAMx耦合的HDDM模块,分析期间德州臭氧敏感性特征及减排方案.结果表明,在空间上,德州市中心城区为VOCs控制区,而郊区为NO_x与VOCs协同控制区.在时间上,VOCs敏感值每日为正值,但dO₃_V₅₀在6月（城区18.7 μg ·m^-3,郊区19.7 μg ·m^-3）和8月（城区15.3 μg ·m^-3,郊区16.4 μg ·m^-3）高于7月（城区13.0 μg ·m^-3,郊区11.8 μg ·m^-3）,NO_x敏感值城区呈正负交错,郊区大部分为正值,并与VOCs敏感值接近.对于城区减排方案应考虑以仅VOCs削减为优先,而郊区由于NO_x和VOCs对臭氧减排效果相当,建议以NO_x：VOCs=1：1为优.     

臭氧-生物活性炭对南方河网典型污染物的去除特性

以我国南方河网原水中有机物和季节性溴化物(Br^-)为对象,研究臭氧-生物活性炭(BAC)工艺净化过程中有机物相对分子质量(M_r)分布变化及溴酸盐(BrO^-₃)和消毒副产物(THMs)的形成规律.结果表明,原水中M_r在10³以下的有机物(DOC)约占总量的80%,常规工艺主要表现为对M_r >100×10³有机物的去除,出水DOC去除率为8%、 SUVA(UV₂₅₄/DOC)值下降14%;臭氧-活性炭工艺主要去除10³<M_r<5×10³的有机物,但亲水性小分子有机物抑制生物降解作用,出水DOC去除率仅提高至30%、SUVA值下降31%.当臭氧投加量高于2 mg/Ｌ时,臭氧氧化出水中BrO^-₃增加明显,氧化过程原水中Br^-浓度升高BrO^-₃生成量增大;生物活性炭对BrO^-₃的去除率平均仅为13%,且波动较大.与常规处理相比,臭氧-生物活性炭处理后各类THMs均有减少,总量减少40%;但氯量和Br^-对溴代副产物影响大,主要为CHBr₃生成量增加.     

基于边界观测的长三角某工业区O3来源特征

为研究上海某石化工业区臭氧来源特征,采用在线监测系统对该工业区O₃及其前体物和气象参数展开了为期3个月（2020年6~8月）的同步连续观测.采用TCEQ（Texas Commission on Environmental Quality）区域背景臭氧估算法和主成分分析两种方法研究工业区区域背景和本地生成O₃浓度贡献,并将两种方法进行对比分析.结果表明：①观测期间园区主导风向为东南风和东风,平均温度为27.12℃.ρ（VOCs-36）日均值为32.05~240.51μg·m^-3,烷烃浓度占比最大;ρ（NO_x）日均值为10.15~47.51μg·m^-3;ρ（O₃）为31.81~144.43μg·m^-3.②TCEQ法得出的区域背景O₃浓度[ρ_R（O₃）]为32.63~191.13μg·m^-3,本地生成O₃浓度[ρ_L（O₃）]为16.08~134.25μg·m^-3,区域背景占比ω（TCEQ）为32.6%~87.7%.主成分分析计算得出的区域背景[ρ_PCA-R（O₃）]为66.38~219.83μg·m^-3;③TCEQ法计算得出的本地生成O₃浓度变化基本能够与该园区内臭氧生成潜势的变化对应,两种方法具有良好的吻合效果,经验证结果具有可靠性;④剔除由于站点浓度异常情况带来的计算误差,观测期间区域背景O₃占比基本处于75%~95%范围内.综上,园区内O₃浓度组成以区域输送为主,应重点关注工业区周边城市的O₃污染治理,落实长三角区域联防联控措施.     

臭氧降解水中苯并三唑反应动力学及效能研究

对臭氧氧化去除水中痕量苯并三唑(BTri)的反应动力学、效能及其影响因素进行了实验研究.结果表明,臭氧分子与BTri直接反应速率常数k_Ｏ3=20.18 L·(mol·s)^-1,臭氧与BTri反应的表观反应速率常数K_BTri随pH值的不同而有显著差异,当pH值由6.63增加到7.83时,表观反应速率常数由63.42 L·(mol·s)^-1提高至582.69 L·(mol·s)^-1,增加约8倍.单独臭氧化可以有效地去除水体中痕量BTri,最终去除率可达85％;随着水体pH值的增加及水体温度的升高,BTri的反应速率大幅度提高;自然水体中常见阴离子NO^-₃、SO^2-₄、Cl^-对臭氧化去除BTri的去除率及反应速率无明显影响;羟基自由基(·OH)抑制剂叔丁醇对臭氧氧化去除BTri有一定的抑制作用,说明·OH也对臭氧氧化去除BTri有一定的贡献,表明臭氧化去除BTri的过程为O₃直接氧化及·OH间接氧化共同作用的结果.     

开放式臭氧浓度升高对2个冬小麦品种光合损伤的研究

在开放式臭氧浓度升高（ozone-free air controlled enrichment,O₃-FACE）平台上,观测了高浓度臭氧（正常大气臭氧浓度的基础上增加50%）对2个冬小麦(Tritcium aestivum L.)品种（烟农19和扬麦16）在灌浆期内功能叶片光合损伤的情况．观测显示,整个灌浆期内2个小麦品种有关参数响应的趋势表现一致:①净光合速率（P_n）逐渐下降,在臭氧处理35 d时,烟农19和扬麦16降幅分别达到56.21%和21.82%．②荧光动力学参数F_v/F_m（最大光化学量子产量）、q_p（光化学淬灭系数）、Φ_exc（PSⅡ有效光化学量子产量）、Φ_PSⅡ（PSⅡ实际光化学量子产量）呈下降趋势,NPQ（非光化学淬灭系数）逐渐上升;在能量分配方面,吸收的光能在PSⅡ天线色素的耗散部分（%D）升高、用于PSⅡ光化学反应的部分（%P）降低,而不属于前两者的其它消耗部分（%X）变化不明显．在臭氧处理35　d时,烟农19和扬麦16的Φ_PSⅡ分别下降24.42%和9.97%.③光合色素参数Chla/Chlb(叶绿素a/叶绿素b）比值上升,而Chlt/Car(叶绿素/叶黄素)的比值下降.④叶绿体内依赖Mg²⁺、Ca²⁺的ATP_ase(ATP酶)活性和ATP含量均增加．上述参数随臭氧处理时间延长,变化幅度和品种间的差异趋于显著,当臭氧处理35 d时,变幅最大,且烟农19变幅显著大于扬麦16．结果表明,在臭氧浓度升高环境下,作物通过增加热耗散、改变色素含量和结构、提高ATP_ase活性等进行防御和损伤修复．随着处理时间的增加,臭氧对冬小麦的光合损伤具有累积效应,且2个品种表现出较大的差异性．     

活性炭纤维去除水中有机微污染物的效果

采用 4种活性炭纤维 (ACF)作为吸附剂 ,对水中 CHCl₃、CCl₄、高锰酸钾指数 COD_Mn、紫外吸光值 E_UV254等有机微污染物的去除进行了初步研究 ,并与 ZJ-15型颗粒活性炭 (GAC)进行了对比 .吸附等温线的结果表明 ,ACF3对 CHCl₃的去除效果最好 ,当 CHCl₃的平衡浓度为 60μg· L^-1 时 ,ACF3对 CHCl₃的吸附容量为 212μg·g^-1 ;GAC对 CCl₄的去除效果最好 ,当 CCl₄的平衡浓度为 3μg· L^-1时 ,GAC对 CCl₄的吸附容量为 0.83μg·g^-1;GAC及 ACF1对 COD_Mn、E_UV254有较好的去除效果 ,当COD_Mn的平衡浓度为 2.5mg·L^-1 时 ,GAC及 ACF1对 CODMn的吸附容量分别为 2.16mg·g^-1 和 1.98mg·g^-1 ,当 E_UV254的平衡浓度为 0.05时 ,GAC及 ACF1对 E_UV254的吸附容量分别为 0.32 g^-1和 0.15g^-1.     

介质阻挡放电等离子体直接分解NOx的影响因素

在以 γ- Al₂O₃小球作为填充物的介质阻挡放电条件下 ,研究放电电压 ( 9～ 16k V)、交流电源频率 ( 50～ 1600 Hz)、NO入口浓度 ( 50～1800 ml/m³)、气体空速 (1000～ 6500 h^-1)、反应温度 ( 20～250℃ )、介质小球比表面积及加入 O₂等因素对 NO分解率的影响 .发现提高放电电压、放电频率及介质小球比表面积能显著增加 NO分解率 ,O₂ 的加入对 NO的等离子体分解有强抑制作用 .     

贵州农村地区冬季典型燃料产生的室内空气PM2.5和CO排放污染特征研究

贵州冬季阴冷潮湿,农村家庭使用原煤和生物质燃料作为家庭做饭和取暖燃料,室内空气污染对居民健康造成潜在危害。论文选取贵州农村地区冬季典型燃料使用产生的室内空气PM_2.5和CO排放为研究对象,研究其排放污染特征,并探讨室内空气CO-PM_2.5浓度间的相关性。研究结果表明,不同类型燃料的家庭室内PM_2.5浓度水平是燃煤 > 燃柴 > 沼气;厨房浓度高于客厅。燃煤的家庭厨房PM_2.5浓度最高,为222.54±41.12 μg/m³,燃柴家庭次之,为130.48±26.53 μg/m³,燃沼气家庭的厨房为74.95±19.20 μg/m³。室内CO浓度较低,不同类型燃料的家庭室内CO浓度水平是燃柴 > 燃煤 > 沼气。燃柴家庭客厅CO浓度最高,为3.16±0.73 mg/m³,其次是燃柴家庭的厨房,为2.76±0.25 mg/m³;燃煤家庭的厨房CO浓度较低,为2.32±0.33 mg/m³;最低为燃沼气家庭的厨房,为0.66±0.07 mg/m³。除沼气村外,燃煤及燃柴家庭室内(厨房和客厅)PM_2.5浓度均超过环境空气质量标准(GB3095-2012)PM_2.5限值75 μg/m³,室内CO浓度均低于该标准中CO限值10 mg/m³。固体燃料燃烧是贵州农村PM_2.5的主要来源,室内PM_2.5和CO浓度相关性分析表明二者不具有显著相关性,采用CO监测值来推算PM_2.5以提高监测效率的应用可能性受到限制。研究表明,贵州农村地区需采取更加有效的干预措施以减少室内空气污染尤其是控制PM_2.5排放。     

微囊藻毒素含量与自然水体环境影响因子的相关性

研究了太湖流域湖州段、杭州市贴沙河和某水华池塘等自然水体的微囊藻毒素水平,利用相关性分析、主成分分析、聚类分析等统计方法,探讨了自然水体中微囊藻毒素MCLR和MCRR与环境影响因子的相关性.结果表明,3处水体的微囊藻毒素MCLR水平为0.049～12.30μg/L,MCRR为0.032～7.90μg/L,底层水中微囊藻毒素的含量显著高于表层水;水体中MCLR的平均浓度与TN、NH₄⁺-N、NO₂^--N和TP呈显著正相关(p<0.01),与水温、DO和氮磷比呈显著负相关(p<0.01),MCRR的平均浓度与NO₃^--N和氮磷比呈显著正相关(p<0.01),与pH、DOC、高锰酸盐指数、光密度呈显著负相关(p<0.01);TP和NO₂^--N是影响MCLR生物合成的主导因子,NO₃^--N和氮磷比是影响MCRR生物合成的重要因子;NO₂^--N和NO₃^--N可能分别是MCLR和MCRR生物合成中利用的主要无机氮源.     

介质阻挡放电产生臭氧的特性研究

臭氧由于具有强氧化性,在众多领域已经得到了广泛的应用。本文通过试验研究了介质阻挡放电产生臭氧的特性。结果表明:外加电压增大时,臭氧浓度和产速都不断增大,臭氧产率则是先增长,达到最大值后又开始略微下降;气体流速增大时,臭氧浓度不断减小,而臭氧产速和产率都是先增长,达到最大值后又开始下降;电源频率在5.0～9.9kHz范围内改变时,臭氧浓度、产速和产率变化不明显;当电介质厚度不变时,在0.3～0.5mm范围内改变间隙厚度,小间隙厚度优势不明显。     

Characteristic of emissive spectrum and the removal of nitric oxide in N2/O2/NO plasma with argon additive

Although the approach using non-thermal plasma (NTP) for deNOx has been studied for over 15 years,how to achieve higher removal efficiency with lower cost is still a barrier for its industrial application.In order to investigate the impact of the argon additive on the electron density,energy and the nitric oxide reduction process in plasma,the spectrum of the dielectric barrier discharge at atmospheric pressure in a coaxial reactor was measured using the monochromater with high resolution and the comparative experiments for NO reduction were carried out simultaneously in the N2/O2/NO plasma stream with and without argon,respectively.The nitrogen molecular spectrum which is attributed to the energy level transition (C3πu→B3πg ) was compared in the wavelength range 300-480 nm and the electron density and temperature were determined by the calculation based on the relative intensities and Stark broadening width of spectral lines.The spectrum results indicated that the argon additive could enhance the intensity of emissive spectrum of plasma,thus the electron concentration as well as the energy was increased,and finally prompted the ionization rate to produce active N,O and O3.The results of NO reduction showed that the NO conversion efficiency increased in the range of 10%-30% with 5% addition of argon in stream comparing with the condition without argon additive.This study will play a positive role in the industrial application of dielectric barrier discharge deNOx reactor.     

剩余臭氧气体分解实验研究

应用强电离介质阻挡放电技术产生的高浓度臭氧气体 ,溶于水后生成的高浓度臭氧水 ,是一种强氧化剂 ,在工业上广泛应用。然而常用的混合器中臭氧不可能被完全利用 ,排出的剩余臭氧气体的浓度较高 ,远大于一类区浓度限值 0 .1 6mg/m3。论述一种利用分子筛吸附与加热相结合的分解方法 ,具有良好效果 ,且设备简单易操作 ,已应用于小型高浓度臭氧水产生设备配套装置中。     

脉冲放电等离子体降解废水中有机物的作用机理探索

借助对脉冲放电过程中产生的多种氧化性组分的定量测定并结合对工艺实验结果的对比分析,探索了脉冲放电等离子体降解4-氯酚的作用机理．放电过程中当从放电电极鼓入氧气时,脉冲放电降解有机物的作用机理过程为：氧气放电产生臭氧,臭氧然后传质到废水中,废水中的臭氧及其分解产物羟基自由基等氧化性物质与废水中的有机物的氧化反应．该作用机理是建立脉冲放电等离子体降解有机物过程数学模型的理论基础．     

脉冲调制介质阻挡放电和催化联用技术降解甲苯

利用低温等离子体处理挥发性有机化合物(VOCs)废气是目前国内外研究的热点。研究利用脉冲调制介质阻挡放电和催化联用技术降解甲苯,对比分析了连续放电和脉冲调制对去除甲苯的影响;研究了脉冲调制后在有无催化剂的情况下的能量效率,比较了两种情况下的臭氧浓度以及中间产物的不同。结果表明:脉冲调制有效提高了甲苯的降解能效,其能量效率几乎是连续放电时的2倍～3倍;在有催化剂的情况下,能量效率是没催化剂的1.5倍～2倍,臭氧浓度明显降低,结焦产物中含苯环的衍生物的量少于无催化的结焦产物。     

平行磁场下电极材料对DBD降解亚甲基蓝的影响

采用介质阻挡放电等离子体技术,以镍,铁,钼,不锈钢4种材料作为电极,分别在有平行磁场和无平行磁场的条件下,考察了不同电极材料对亚甲基蓝降解率和能量利用率的影响.实验中发现电极材料的不同会影响亚甲基蓝的降解效果,其中镍电极在处理8min后亚甲基蓝降解率可达99%,降解效果最好,电极材料还会影响平行磁场对亚甲基蓝降解的促进效果,铁和镍电极的能量利用率相比无磁场时提高了约20%,而钼和不锈钢只有5%~10%.通过研究介质阻挡放电等离子体的产生机理和二次电子发射原理,发现这些差异是由电极材料的二次电子发射系数和磁导率的不同导致的,4种材料中铁的二次电子发射系数最大,电子雪崩过程中产生的高能电子更多,因此降解效果最好,铁和镍的磁导率最大,放电空间内的磁感应强度更高,因此平行磁场对亚甲基蓝降解率和能量利用率的提升更大.     

Toluene removal characteristics by a superimposed wire-plate dielectric barrier discharge plasma reactor

A superimposed wire-plate dielectric barrier discharge reactor was used to remove toluene in this study. The effects of oxygen content, gas flow rate, gas initial concentration and with/without catalyst on toluene decomposition were investigated. It was found that an optimal toluene removal was achieved when the oxygen content was about 5%. Under this condition, the highest toluene removal efficiency of 80.8% was achieved when the gas concentration was 80 mg/m^3. The toluene removal efficiency decreased with the increase of the gas flow rate and the initial concentration of toluene. In addition, the ozone concentration decreased with the increase of the initial concentration of toluene. It suggested that combining DBD （dielectric barrier discharge） with Co3O4/Al2O3/foam nickel catalyst in-situ could improve the toluene removal efficiency and suppress ozone formation. Products analysis showed that the main products were CO and CO2 when oxygen was more than 5%.     

Characteristics of NO reduction with non-thermal plasma

As a new type of NO removal system, NO reduction in N2-NO plasma was applied to solve the difficulties in the traditional methods, such as higher energy-consumption, larger equipment size and high cost, and so on. Using the experimental NO reduction system with single-pair electrode tip discharge structure, the NO reduction characteristics of N~-NO system were revealed to guide the engineering practice; the results of NO reduction with single-pair electrode tip discharge plasma also have the same instructive meaning to the NO reduction with multi-pair electrode tip discharge plasma. The amount of both active N atom and NO removal rate increased with the distance /g increasing between the two electrode tips and then dropped when the distance exceeded a certain value. The NO removal rate increased while the voltage between two electrode tips or the resident time of gas flow increased. The distance is a key geometrical variable factor that can determine the intensity of electric field between two electrode tips and the resident time of gas. In this paper, the effects of the dielectric features on NO reduction using dielectric-barrier discharge plasma system were also studied. The results of NO removal rate with different dielectrics such as Al2O3, CaO. MgO and glass showed that the electric field intensity is different with different dielectric, because it brings different energy to particles in discharge room and thus it causes different NO removal rate.     

Toluene decomposition performance and NOx by-product formation during a DBD-catalyst process

Characteristics of toluene decomposition and formation of nitrogen oxide(NOx) by-products were investigated in a dielectric barrier discharge(DBD) reactor with/without catalyst at room temperature and atmospheric pressure. Four kinds of metal oxides, i.e., manganese oxide(Mn Ox), iron oxide(Fe Ox), cobalt oxide(Co Ox) and copper oxide(Cu O), supported on Al2O3/nickel foam, were used as catalysts. It was found that introducing catalysts could improve toluene removal efficiency, promote decomposition of by-product ozone and enhance CO2 selectivity. In addition, NOx was suppressed with the decrease of specific energy density(SED) and the increase of humidity, gas flow rate and toluene concentration, or catalyst introduction. Among the four kinds of catalysts, the Cu O catalyst showed the best performance in NOx suppression. The Mn Ox catalyst exhibited the lowest concentration of O3 and highest CO2 selectivity but the highest concentration of NOx. A possible pathway for NOx production in DBD was discussed. The contributions of oxygen active species and hydroxyl radicals are dominant in NOx suppression.     

Research on the degradation mechanism of pyridine in drinking water by dielectric barrier discharge

Pyridine, an important chemical raw material, is widely used in industry, for example in textiles,leather, printing, dyeing, etc. In this research, a dielectric barrier discharge(DBD) system was developed to remove pyridine, as a representative type of nitrogen heterocyclic compound in drinking water. First, the influence of the active species inhibitors tertiary butanol alcohol(TBA),HCO_3~-, and CO_3~(2-)on the degradation rate of pyridine was investigated to verify the existence of active species produced by the strong ionization discharge in the system. The intermediate and final products generated in the degradation process of pyridine were confirmed and analyzed through a series of analytical techniques, including liquid chromatography–mass spectrometry(LC–MS), high performance liquid chromatography(HPLC), ion chromatography(IC), total organic carbon(TOC) analysis, ultraviolet(UV) spectroscopy, etc. The results showed that the degradation of pyridine was mainly due to the strong oxidizing power of ozone and hydroxyl radical produced by the DBD system. Several intermediate products including 3-hydroxyl pyridine, fumaric acid, 2, 3-dihydroxypyridine, and oxalic acid were detected. Nitrogen was removed from the pyridine molecule to form nitrate. Through analysis of the degradation mechanism of pyridine, the oxidation pathway was deduced. The study provided a theoretical and experimental basis for the application of DBD strong ionization discharge in treatment of nitrogen heterocyclic compounds in drinking water.