DBD降解CF2ClBr过程中自由基与电子能量

利用介质阻挡放电方法对环境污染物CF2ClBr进行了等离子体降解的研究.在前人对该体系的降解产物分析及活性粒子推测的基础上,采用动态反应装置得到了等离子体的发射光谱,进一步确证了等离子体系中出现的CF2、CFCl、F、Cl、Br等主要自由基,并从中推出了等离子态气体可能发生的自由基反应.同时通过发射光谱的分析,近似得到该体系的平均电子能量约为2.42eV.     

Investigation of a new approach to decompose two potent greenhouse gases: photoreduction of SF(6) and SF(5)CF(3) in the presence of acetone

In this paper, we addressed the utilization of photochemical method as an innovative technology for the destruction and removal of two potent greenhouse gases, SF(6) and SF(5)CF(3). The destruction and removal efficiency (DRE) of the process was determined as a function of excitation wavelength, irradiation time, initial ratio of acetone to SF(5)X (X represented F or CF(3)), initial SF(5)X concentration, additive oxygen and water vapor concentration. A complete removal was achieved by a radiation period of 55min and 120min for SF(6)-CH(3)COCH(3) system and SF(5)CF(3)-CH(3)COCH(3) system respectively under 184.9nm irradiation. Extra addition of water vapor can enhance DRE by approximately 6% points in both systems. Further studies with GC/MS and FT-IR proved that no hazardous products such as S(2)F(10), SO(2)F(2), SOF(2), SOF(4) were generated in this process.     

Different reaction mechanisms of diphenylether and 4-bromodiphenylether with nitrous acid in the 355 nm laser flash photolysis of mixed aqueous solution

The microscopic reaction mechanisms of diphenylether (DPE) and 4-bromodiphenylether (4-BrDPE) with nitrous acid (HNO(2)) in the absence of O(2) have been explored by the 355nm laser flash photolysis. It was proposed that OH radical, from the photolysis of HNO(2), added to DPE forms the C(12)H(10)O-OH adduct while added to 4-BrDPE forms the 4-BrDPE-OH and 4-BrOH-DPE adducts. The first-order decay rate constants of the C(12)H(10)O-OH adduct, 4-BrDPE-OH adduct and 4-BrOH-DPE adduct were measured to be (1.86+/-0.14)x10(5)s(-1), (2.19+/-0.04)x10(5)s(-1) and (1.56+/-0.03)x10(5)s(-1), respectively. The final photolysis products of DPE and HNO(2) identified by GC/MS analysis were phenol, o-hydroxydiphenylether, p-hydroxydiphenylether and p-nitrodiphenylether, while the final photolysis product of 4-BrDPE and HNO(2) identified by LC/MS analysis was mainly the dimer.     

新型β-PbO2电极电解处理茜素红废水的研究

采用高压塑片工艺制备新型β-PbO2电极,该工艺简单易行,且所得β-PbO2电极具有很好的抗腐蚀性能.为研究该电极的电催化性能,探讨了电极间距、电解时间、茜素红初始浓度、外加电压、初始pH等条件对该电极降解茜素红染料效果的影响,并与石墨电极进行对比.结果表明,β-PbO2电极在脱色和COD去除方面都有明显的优越性.根据茜素红的分子结构和电解产物气相色谱—质谱联用(GC/MS)仪分析结果,初步探讨了茜素红降解的反应机制.     

In situ electron-induced reduction of NOx via CNTs activated by DBD at low temperature

• An in situ electron-induced deNO_x process with CNT activated by DBD was achieved. • Carbon atoms on CNT surface were verified to be excited by plasma in DBD-CNT system. • Reactions between NO_x and excited C result in synergistic effect of DBD-CNT system. In this study, a new in situ electron-induced process is presented with carbon nanotubes (CNTs) as a reduction agent activated by dielectric barrier discharge (DBD) for nitrogen oxide (NO_x) abatement at low temperature (<407 K). Compared with a single DBD system and a DBD system with activated carbon (DBD-AC), a DBD system with carbon nanotubes (DBD-CNT) showed a significant promotion of NO_x removal efficiency and N₂ selectivity. Although the O₂ content was 10%, the NO_x conversion and N₂ selectivity in the DBD-CNT system still reached 64.9% and 81.9% at a specific input energy (SIE) of 1424 J/L, and these values decreased to 16.8%, 31.9% and 43.2%, 62.3% in the single DBD system and the DBD-AC system, respectively. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were utilized to investigate surface changes in the CNTs after activation by DBD to explore the NO_x reduction abatement mechanism of this new process. Furthermore, the outlet gas components were also observed via Fourier transform infrared spectroscopy (FTIR) to help reveal the NO_x reduction mechanism. Experimental results verified that carbon atoms excited by DBD and the structure of CNTs contributed to the synergistic activity of the DBD-CNT system. The new deNO_x process was accomplished through in situ heterogenetic reduction reactions between the NO_x and carbon atoms activated by the plasma on the CNTs. In addition, further results indicated that the new deNO_x process exhibited acceptable SO₂ tolerance and water resistance.     

介质特性对DBD降解苯的影响

为了提高介质阻挡放电(dielectric barrier discharge,DBD)等离子体的处理效率,研究了内外介质组成分别为:(1)石英 石英;(2)陶瓷 石英;(3)陶瓷 陶瓷这3种情况下苯的降解情况.试验结果表明,在处理低浓度含苯废气时,陶瓷 陶瓷效果最好;陶瓷(内管) 石英(外管)在处理高浓度含苯废气时显示出优势.通过对气相产物和固相结焦产物的分析验证了DBD能有效降解苯,降解产物不会带来新的污染.进一步分析了实验条件和介质材料的变化对DBD降解苯的影响机理.     

自然灾害防控产业的技术突破与发展路径战略研究∗

在全球气候变化及地质活动日益活跃的孕灾大环境下,我国亟待实现自然灾害的快速高效应急处理,相应的灾害防控产业升级同样势在必行。结合自然灾害防控关键环节的发展方向,通过文献整理、现场调研、专家咨询及问卷调查等方式,分析了自然灾害防控产业面临的问题与挑战,开展自然灾害防控产业技术突破与发展路径的研究,提出以下对策措施：构建更为完善的标准化体系,严格核定从业资格,实时把控自然灾害防控产业的市场动态, 保障产业市场良性竞争;立足本土化发展优势,集群化发展自然灾害防控产业,贯通自然灾害多产业链条;以自然灾害防灾减灾的基础研究为主导,通过理论创新和技术迭代,完成自然灾害产业升级,提升产业整体性、系统性和协同性,打造防灾减灾产业端的国际核心竞争力。本文将为自然灾害防控的产业高质量快速发展提供前瞻性、针对性、储备性的科学参考。     

DBD降解CF2ClBr过程中自由基与电子能量

利用介质阻挡放电方法对环境污染物ＣＦ₂ＣｌＢｒ进行了等离子体降解的研究．在前人对该体系的降解产物分析及活性粒子推测的基础上,采用动态反应装置得到了等离子体的发射光谱,进一步确证了等离子体系中出现的ＣＦ₂、ＣＦＣｌ、Ｆ、Ｃｌ、Ｂｒ等主要自由基,并从中推出了等离子态气体可能发生的自由基反应．同时通过发射光谱的分析,近似得到该体系的平均电子能量约为２．４２ｅＶ     

Study on gaseous CS2 using laser-induced fluorescence

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等离子体降解水相中有机污染物的机理研究

研究了等离子体在内电极通氧条件下降解水相中甲基紫的机理。研究表明，甲基紫的降解率与等离子体的电压和处理时间呈线性关系、与甲基紫溶液的浓度呈指数关系，溶液的pH随着处理时间的增加而下降：100mg/L甲基紫经等离子体外理3s，其降解率可达95%以上，COD下降50%左右；在等离子体条件下，甲基紫溶液的降解是氧原子、电子、活性自由基和离子等共同的作用的结果。