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1、6.4.1 6.4.1 非平衡等离子体空气净化非平衡等离子体空气净化 6.4.2 6.4.2 光催化净化方法光催化净化方法 6.4.3 6.4.3 负离子净化方法负离子净化方法6.4.4 6.4.4 臭氧净化方法臭氧净化方法稀释比为稀释比为1:1000情况下未经情况下未经放电处理的细菌生长迹象放电处理的细菌生长迹象稀释比为稀释比为1:1000情况下经(情况下经(8 kV)放电处理的细菌生长迹象)放电处理的细菌生长迹象 等离子体放电催化消除微生物污染等离子体放电催化消除微生物污染1. What is Plasma?UniverseNebulaSolar WindAuroraLightningFl
2、uorescentPlasmas The 4th State of MatterpIn 1879, Crookes first suggested that the ionized state of gases should be considered a 4th state of matter.pIn 1929, Langmuir used “plasma” to describe the ionized gases.pPlasmas account for 99.9% of the mass of the known universe.Phil. Mag., 7, 57, 1879 Phy
3、s. Rev., 33, 954, 1929PlasmaWhats Special?pElectrons are generally near thermal equilibrium with E and B fields.pIonss and neutral gas temperatures in thermodynamic equilibrium is their mean translational energy. pIons generally are not in thermal equilibrium with the fields.pThermal Plasma Te= Tion
4、spNonthermal Plasma Te TionsPlasma Atoms1 eV= 11604 KYan Keping. NTPC Lecture-1 gaseous dischargePlasma DischargepCorona Discharges Weakly luminous discharge, which appears at atmospheric pressure near sharp points, edges, or thin wires, where the electric field is sufficiently large.pStreamer Thin
5、ionized channel that rapidly propagates between electrodes along the positively charged trail left by an intensive primary avalanche.pGlow Characterized as by several diffuse luminous zones. Not filamentary discharge.pArc Characterized by its low voltage drop and high current density.(thermal plasma
6、)2. The Applications of PlasmapNuclear FusionpChemical SynthesispSurface TreatmentpMedicinepPollution ControlpLight SourcespPropulsionpLaserspSwitchespVolume ProcessingpFlat-Panel DisplayspRadiation ProcessingpMaterial AnalysispThermal Plasma for Nuclear FusionpTokamak and Nuclear FusionNanopowder S
7、ynthesis & DepositionPlasma DevicePlasma Enhanced Chemical Vapor DepositionJournal of Power Sources, 170, 2007, 308-323Plasma Surface TreatmentpSurface Treatment and Modificationhttp:/ before reaction (b) after reactionY.-F. Guo et al. / Journal of Molecular Catalysis A: Chemical 245 (2006) 93100App
8、lied Plasma MedicinepAnimal and Human Living Tissue Sterilization15 s5 mincontrolApplied Plasma MedicinepPlasma-Assisted Blood CoagulationBlood coagulation on a live animalG. Fridman.ICPM-1, 2007, Corpus Christi, Texas.Applied Plasma MedicinepPlasma Use for Skin RegenerationFacial appearance before
9、(A) and 3 months after (B) plasma skin regeneration, with improvement in pigmentation and skin texture. Investigator-rated improvement on the 9-point facial rhytid scale changed from 7 (before regeneration) to 6 (after regeneration); patient-rated improvement in overall skin rejuvenation was 90%.M.
10、A. Bogle, K. A. Arndt, J. S. Dover, Arch. Dermatol. 2007, 143,168.Plasma for Removal of VOCs +Electrode High Voltage PowerElectrodeDielectric Barrier Post-plasmaPlasmaInterfaceCatalystCatalystGas inGas outpDBD Reactor 气体放电处理气体放电处理VOCs(特别是除臭)(特别是除臭)p几种化学活化机制过程手段过程手段能量分配能量分配效应效应温度温度所有分子被加热所有分子被加热只有分布在
11、末端的能量被利用只有分布在末端的能量被利用催化剂表面催化剂表面 接近表面那层被加热接近表面那层被加热 催化剂降低活化能催化剂降低活化能电场电场只产生电场只产生电场直接和化学键作用直接和化学键作用(如(如Stark效应)效应)电子电子只有电子被加热只有电子被加热调谐能低于活化能调谐能低于活化能气体放电处理气体放电处理VOCsp实现实现VOCs低温去除低温去除p适用于低浓度、大风量的适用于低浓度、大风量的VOCsp处理效率高、能耗低处理效率高、能耗低p净化空气净化空气活性物种和臭氧,触发催化活性物种和臭氧,触发催化剂,降低活化能。催化剂选剂,降低活化能。催化剂选择性地与等离子体择性地与等离子体 产
12、生的产生的产物再产物再 反应反应u放电区域富集大量活性物放电区域富集大量活性物种,如离子、电子、激发态种,如离子、电子、激发态的原子、分子及自由基等;的原子、分子及自由基等;活性物种将污染物分子离解活性物种将污染物分子离解小分子物质小分子物质催化剂催化剂污染物污染物CO2H2O能量能量活性物种活性物种e,O2-,OOH,O3,无害化无害化气体放电处理气体放电处理VOCsp降解产物u完全降解产物,H2O, CO2u气相副产物,VOCs、臭氧,NOxu气溶胶p理想模式p2个科学与技术的问题(1) 能耗能耗 (J/L)(2) 副产物排放副产物排放VOCs处理过程产生的气溶胶气溶胶静电收集气相副产物F
13、TIR谱图VOCs气体放电气体放电气溶胶气溶胶 H2O, CO2收集收集 小分子物质小分子物质氧化氧化ESP催化催化光催化净化的基本原理示意图光催化净化的基本原理示意图 采用光催化氧化技术能在室温下利用空气中的水蒸汽采用光催化氧化技术能在室温下利用空气中的水蒸汽和氧气去除空气中的污染物。和氧气去除空气中的污染物。光催化空气净化器基本净化流程光催化空气净化器基本净化流程hv EgEg= 3.2eV-e+h 380nm2TiO22CO ,H O,etc-e或2VOCsH O2O-2O+VOCsHO2. 空气负离子的净化作用空气负离子的净化作用其原理是其原理是借助凝结和吸附作用借助凝结和吸附作用。负离子净化灯负离子净化灯1. 空气离子的来源、类型和特性空气离子的来源、类型和特性3. 空气负离子产生技术空气负离子产生技术 到目前为止,空气负离子的发生技术主要有:到目前为止,空气负离子的发生技术主要有:电晕放电晕放电、水发生和放射发生电、水发生和放射发生三种。三种。负离子空气净化保健漆负离子空气净化保健漆
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