Catalysis assisted plasma decomposition of benzene using dielectric barrier discharge

Atmospheric non‐thermal plasma generated by dielectric barrier discharge was applied to decompose benzene with a sheet type catalyst of platinum supported by alumina. The experimental results indicated that an enhancement of the decomposition by the catalyst was achieved at low concentration of benzene. Ozone produced in the plasma seemed not to contribute to the decomposition. The deactivation of the catalyst was also observed due to decomposition products such as CO and a solid deposit. However a heating treatment could regenerate the catalyst. The results suggested the plasma‐catalyst hybrid reactor was the effective method to solve volatile organic compound (VOCs) problem.     

介质阻挡放电技术处理挥发性有机物的研究进展

介质阻挡放电技术在处理低浓度挥发性有机物（VOCs）过程中具有反应快速、工艺简单及适应范围广等优点而受到广泛关注。本文从介质阻挡放电单独使用和介质阻挡放电协同催化两方面进行了概括总结。首先,简述了介质阻挡放电处理VOCs所用的驱动电源和等离子体发生器的研究现状及气体性质对VOCs降解性能的影响;其次,介绍了介质阻挡放电协同催化的两种方式（内置式和后置式）及各自情况下采用不同催化剂强化VOCs去除性能、提高能量效率、抑制副产物生成的过程机理;最后,分析了介质阻挡放电技术处理低浓度VOCs过程中存在的关键问题,并提出了未来的重要研究方向为：等离子体催化体系中VOCs的界面反应机理;催化剂的抗积碳性能的提高;适用于多组分VOCs的高效催化剂的开发。     

Hydrogen from steam methane reforming by catalytic nonthermal plasma using a dielectric barrier discharge reactor

A scaled-up dielectric barrier discharge (DBD) reactor has been developed and demonstrated for the production of hydrogen from steam methane reforming (SMR) by catalytic nonthermal plasma (CNTP) technology. Compared to SMR, CNTP offers conversion at ambient pressure (101.325 kPa), low temperature with better efficiency, making it suitable for distributed hydrogen production with small footprint. There have been several lab-scale DBD reactors reported in the literature. Dimension of the scaled-up DBD reactor is about six times the lab-scale version and can produce 0.9 kg H₂/day. The scale-up is, however, nonlinear; several technical innovations were required including spray nozzle for homogeneous introduction of steam, perforated tube central electrodes for generation of homogeneous plasma. Conversion efficiency of the scaled-up DBD reactor is 70–80% at 550°C and 500 W. A continuous run of 8 hr was demonstrated with typical product gas composition of 69% H₂, 6% CO₂, 15% CO, 10% CH₄.     

介质阻挡放电等离子体对PP非织造布的改性

利用常压介质阻挡放电(DBD)设备,研究了工作气体、放电电压、处理时间、试样布置方式等对聚丙烯(PP)熔喷非织造布吸水率和处理效果均匀性的影响。结果表明:PP非织造布试样在90kV下用氩等离子体处理40s,吸水率达672%,在氩气中混入少量氧气(Ar/O2体积比为10/1),吸水率可提高至717%;试样吸水率随处理时间及放电电压的增加均提高,可以通过增大放电电压来有效地降低处理时间;随着DBD等离子体处理强度的增加,PP非织造布整体亲水性和表观均匀性均得到有效提高;试样布满放电区域有利于提高其吸水率和处理效果的均匀性。     

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1.3 W,放电间距为2.5 mm,气体流量为150 ml·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。     

介质阻挡放电等离子体处理芳纶的表面性能研究

采用介质阻挡放电(DBD)装置对芳纶1414表面进行改性处理,探讨低温等离子体处理对纤维表面性能的影响。结果表明:经过DBD等离子体处理后,芳纶1414纤维表面粗糙程度加剧,粘结性能和浸润性能有了明显的改善;当DBD等离子体处理功率为200～300 W,时间为60 s,氩气流量为2～3 L/min时,芳纶1414的界面剪切强度从处理前的11.9 MPa上升到14.2 MPa,接触角由处理前的85.0°下降到了60.6°。     

埃洛石吸附-介质阻挡放电等离子体处理亚甲基蓝废水

为进一步提高对亚甲基蓝(MB)的降解效果,提出了介质阻挡放电等离子体协同吸附方法,并利用XRD、FTIR方法对吸附剂进行表征分析。研究结果表明,处理120 min后,协同体系对MB的降解率为96.36%。当MB的初始质量浓度为50 mg/L、HNTs的投加量为70 mg/L、放电功率为150 W、pH为6.7、通气量为200 m L/min时,MB的去除效果较好。     

双介质阻挡放电低温等离子体对模拟堆肥气体中氨气的去除

针对固体废物堆肥设施氨气污染问题,本文首次运用双介质阻挡放电低温等离子体（DDBD）技术去除模拟堆肥气体中的氨气。考察了输入功率、氨气流速、氨气初始浓度、反应器放电间隙、氧气含量等参数对氨气去除率和低温等离子体系统能量效率的影响,并分析了副产物的生成情况及其影响因子。研究结果表明,氨气去除率与输入功率和氧气含量呈正相关,与氨气流速和氨气初始浓度呈负相关。低温等离子体系统的能量效率与氨气流速、氨气初始浓度、氧气含量均正相关,但随输入功率的增加先升高后降低。研究发现,在所设定的反应条件下,4mm放电间隙反应器的能耗最低,能量效率最高。O₃和NO_x是DDBD去除氨气的反应副产物,其浓度均与氧气含量呈正相关,均呈现随输入功率的增加先升高后降低的趋势。     

大气压介质阻挡放电及协同催化剂脱硝研究进展

受绿色生态和可持续发展战略理念的驱动,废气排放对环境造成的危害备受关注。NO _x 作为废气的主要污染物之一,是废气污染物控制的重点与难点。基于此,本文介绍了传统后处理脱硝技术的优缺点及应用现状,回顾了介质阻挡放电（DBD）基础研究,分析了DBD脱硝性能,重点阐述了DBD协同催化剂脱硝及脱硝机理。分析指出：①DBD驱动电源与反应器结构是制约脱硝性能的关键因素;②单独DBD技术脱硝性能较差,而DBD协同催化填充床技术展现出优异的脱硝性能和较高的N₂选择性;③等离子体协同催化脱硝机理研究主要包括等离子体特征参数诊断、流体模型验证、等离子体传播机制分析以及原位表征,而在等离子体催化理论计算方面的研究较为缺乏。因此,未来DBD协同催化脱硝技术应立足如下几个方面发展：研发高功率、低能耗电源,提升废气NO _x 处理量;优化反应器结构,提升脱硝的效率与选择性;设计与构筑适宜于DBD环境的脱硝催化剂;深入全面分析DBD协同催化剂脱硝机理。     

介质阻挡放电在芳纶表面改性中的应用

综述了介质阻挡放电应用于芳纶表面改性研究的最新进展;介绍了介质阻挡放电的机理、特点以及国内主要的介质阻挡放电等离子体的设备;阐述了介质阻挡放电对芳纶亲水性能和粘结性能等表面性能的改善。指出芳纶等离子体表面改性的时间效应限制了其广泛应用,应进一步加强纤维表面等离子体改性的机理研究。     

Removal of iopromide from an aqueous solution using dielectric barrier discharge

BACKGROUND: Both ionic and nonionic ICM are recalcitrant to ozone and traditional waste water treatment plants. In this study, the efficiency of one kind of ICM‐iopromide (IOPr) removal from an aqueous solution using a dielectric barrier discharge (DBD) method was investigated. RESULTS: An energy density of 1.5E05 J L^?1 resulted in the most significant removal (98.8%) of IOPr. At this energy density, no decrease in total organic carbon (TOC) was observed. Based on the IR spectra, degradation of the IOPr molecule involved hydroxylation, carbonylation and deiodination. BOD₅/COD measurements indicated that the biodegradability of IOPr increased significantly as a result of DBD treatment. The byproducts of IOPr after DBD treatment were more polar and easily adsorbed and biodegraded by the activated sludge. The removal of IOPr from the solution followed first‐order kinetics, with Ks of 0.10 min^?1, 0.11 min^?1, 0.44 min^?1 and 0.15 min^?1 corresponding to energy densities of 1E + 05 J L^?1, 1.3E + 05 J L^?1, 1.5E + 05 J L^?1 and 1.8E + 05 J L^?1, respectively. The kinetics of the deiodination reactions were more complex due to subsequent iodide oxidation. CONCLUSION: DBD is very effective as a pretreatment or advanced treatment method for increasing the recalcitrant chemical's biodegradability and making subsequent biological treatment more efficient. © 2012 Society of Chemical Industry     

介质阻挡放电微等离子体分解二氧化碳研究

二氧化碳既是主要的温室气体之一,也是包含碳和氧的资源,把相对惰性的CO₂转化为易于利用的CO是其利用的方法之一。采用介质阻挡微等离子体反应器通过单变量和正交实验探究了反应器参数(放电区长度、放电间距、介质厚度)和工艺参数(输入功率、放电频率和停留时间)对CO₂分解为CO的转化率和能量效率的影响规律。研究结果表明,影响CO₂转化率的大小顺序依次为：放电间距>放电长度>输入功率≈停留时间>介质厚度>放电频率;输入功率60.0 W、放电频率9.0 kHz和停留时间1.5 s、放电区长度60 mm、放电间距0.5 m、介质厚度1.6 mm时,CO₂的转化率为10.6%,能量效率为4.1%。     

介质阻挡放电脱硫脱硝过程特性

氮氧化物和硫氧化物在介质阻挡放电(DBD)反应器中的脱除率与很多因素有关,如氧气含量、相对湿度和烟气中SO_2的初始浓度等。本文通过改变SO_2初始浓度、氧气含量和相对湿度来研究脱除氮氧化物和硫氧化物过程中的反应机理。结果发现,在N_2/SO_2/NO体系中SO_2初始浓度在较大范围内变化对NO和SO_2的脱除率影响很小;而N_2/NO/SO_2/H_2O体系中相对湿度的增加对SO_2的脱除的影响较NO的影响大,增加烟气中相对湿度能明显减少SO_2在烟气中的浓度;N_2/NO/SO_2/O_2体系中氧气的增加对SO_2的脱除效率影响不明显,但能促进NO氧化成NO_2或者其他的氮氧化物,同时,在一定的条件下,也能加速NO的生成。探讨NO和SO_2的反应机理,发现SO_2的反应主要与OH和水合电子有关,而NO的反应与O、N等活性基相关。     

介质阻挡放电技术再生Pd/AC催化剂的机理探讨

利用介质阻挡放电对失活钯炭催化剂(Pd/AC)进行再生,并通过催化臭氧氧化硝基苯反应评价再生后催化剂的活性。运用扫描电镜(SEM)、比表面积测定(BET)、热重分析(TG)等测定手段对Pd/AC进行表征;并对放电过程进行臭氧产量测定和等离子体发射光谱诊断,分析了Pd/AC催化剂再生的机理。结果表明,催化剂经放电处理30 min后再生率为95%;利用在最优条件下再生的Pd/AC进行催化臭氧氧化反应,硝基苯的降解率为87%;再生过程中臭氧贡献率仅为25.6%,表明放电过程中产生的强氧化性自由基是促使催化剂再生的主要因素。     

介质阻挡放电等离子体改性碳基材料研究进展

介质阻挡放电等离子体因其高效、经济和易操作等优点, 使得其在材料表面改性方面得到了广泛的应用, 同时表现出良好的应用前景。碳基材料由于其许多良好的物化性能, 使得其在很多领域都得到了很好的应用。而经DBD改性后的碳基材料表现出更好的物化性能, 应用更加广泛。主要综述了DBD在改性碳基材料方面的研究现状, 包括活性基团的引入, DBD改性对碳基材料界面结合能、吸附性能、物理结构及其对负载组分分散度的影响。指出改性过程中仍然存在的许多不够完善之处, 提出许多需要进一步深入研究的问题, 如DBD改性对碳基材料物化性能影响的机理研究, 并展望了DBD改性碳基材料技术未来的发展前景。     

双杆介质阻挡放电降解酸性红73废水

研究一种双杆式介质阻挡放电在不同条件下对酸性红73的降解效果,考察了能量密度、初始电导率、初始pH、初始质量浓度和放置时间等因素对染料降解率的影响,并对反应中生成的活性粒子（H₂O₂和O₃）进行了检测。降解实验前后的紫外-可见吸收光谱图表明介质阻挡放电能够破坏酸性红73分子中的偶氮双键和萘环等。实验结果表明：能量密度的增加可以提高酸性红73降解率,当能量密度为265.8kJ/L时,降解率为70.0%,能量效率最高可达2.84mg/（kW·h）。酸性红73的初始质量浓度的增加可以提高反应的能量效率。放电过程中产生的过氧化氢与处理时间呈正相关增长,并可持续存在一段时间进一步引起染料褪色,臭氧则随着时间的增长先增大后减小。     

Stainless steel membrane distributor-type dielectric barrier discharge plasma reactor for co-conversion of CH4/CO2

Flow arrangement in a dielectric barrier discharge (DBD) plasma reactor is key to affecting multi-component gas reactions. Herein, a stainless-steel membrane distributor-type DBD reactor was developed to allow the change of gas flow arrangements freely to understand their effect on plasma-assisted CH₄/CO₂ co-conversion to syngas. Variation of gas flow arrangements in the DBD reactor could regulate the reaction performance. Also, the inclusion of quartz wool in the DBD reactor could enhance the effect of gas flow arrangement compared to the plasma-alone DBD. Especially, the DBD reactor with CO₂ feed in the quartz wool-packed discharge zone and CH₄ distributed via the membrane exhibited good stability over 600 min on stream, with rather stable CO₂/CH₄ conversions of ~25%/20%, H₂/CO selectivities of ~50%/32%, H₂/CO molar ratio of 0.9–1.1, and energy efficiency of ~0.20 mmol·kJ⁻¹ based on the conversion of feed gases.     

Continuous flow removal of acid fuchsine by dielectric barrier discharge plasma water bed enhanced by activated carbon adsorption

Continuous processes which allow for large amount of wastewater to be treated to meet drainage standards while reducing treatment time and energy consumption are urgently needed. In this study, a dielectric barrier discharge plasma water bed system was designed and then coupled with granular activated carbon (GAC) adsorption to rapidly remove acid fuchsine (AF) with high efficiency. Effects of feeding gases, treatment time and initial concentration of AF on removal efficiency were investigated. Results showed that compared to the N2 and air plasmas treatments, O2 plasma processing was most effective for AF degradation due to the strong oxidation ability of generated activated species, especially the OH radicals. The addition of GAC significantly enhanced the removal efficiency of AF in aqueous solution and shorten the required time by 50%. The effect was attributed to the ability of porous carbon to trap and concentrate the dye, increasing the time dye molecules were exposed to the plasma discharge zone, and to enhance the production of OH radicals on/in GAC to boost the degradation of dyes by plasma as well as in situ regenerate the exhausted GAC. The study offers a new opportunity for continuous effective remediation of wastewater contaminated with organic dyes using plasma technologies.     

Influence of operating parameters on plasma polymerization of acrylic acid in a mesh-to-plate dielectric barrier discharge

Plasma polymerization of acrylic acid is an interesting research subject, since the obtained coatings can have significant biomedical applications due to their high surface density of carboxylic acid groups. In this work, plasma-polymerized acrylic acid (PPAA) films are synthesized using a mesh-to-plate dielectric barrier discharge operated at medium pressure (10.0 kPa). Results clearly show that this reactor setup is able to deposit uniform PPAA films in contrast to the commonly used parallel plate reactor. Moreover, carefully planned experiments are conducted to study the influence of discharge power and monomer concentration on the chemical composition and thickness of the PPAA films. Results clearly show that input power strongly influences the properties of the deposited films: with increasing discharge power, monomer fragmentation in the discharge increases leading to a decrease in carboxylic acid functional groups and a lower polymer deposition rate. The effect of monomer concentration is less pronounced: only at very low monomer concentration (0.1 g/h), a decrease in carboxylic acid functional groups can be observed. The chemical composition and thickness of the PPAA films can thus be tailored by adjusting the operational parameters of the discharge.