Mn-Fe-Ce/Al_2O_3/堇青石催化剂低温NH_3-SCR脱硝性能研究

先采用溶胶凝胶法在堇青石蜂窝陶瓷载体上涂覆铝溶胶浆液,再通过浸渍法负载活性组分Mn和助剂,制备了NH3选择性催化还原NOx低温脱硝催化剂Mn-Fe-Ce/Al2O3/堇青石,实验结果显示:Ce和Fe的添加可以明显提高催化剂的低温脱硝活性,在体积空速4 000 h-1时和120℃条件下,NO转化率由86.3%提高到93.5%,并且在120~300℃范围内,NO的转化率均保持在93%以上。XRD、BET、NH3-TPD和H2-TPR结果表明:Fe和Ce改性后增加了催化剂的比表面积和孔体积、酸性位点、NH3的吸附能力和氧化能力,提高了催化剂的SCR活性。     

Ce掺杂对钒钨钛催化剂脱硝性能的影响

对钒钨钛（V-W-Ti）催化剂进行Ce掺杂改性制备了CexV1W7/Ti（x%为CeO2负载量）,通过XRD、TEM、FTIR、XPS等表征其结构和元素组成,通过NH3/NO-TPD表征NH3和NO在催化剂表面的吸附强弱分布,并测试不同CeO2负载量下催化剂的脱硝性能,最后经密度泛函理论(DFT )计算探究催化剂的失活机理。结果表明,负载CeO2增加了催化剂表面化学吸附氧的比例和Br?nsted酸性位点,但也减少了催化剂表面V4+的比例和Lewis酸性位点;适当CeO2负载量能显著提高钒钨钛催化剂的中低温活性,但负载量过多会降低催化剂的高温活性,CeO2负载量为1% （以催化剂质量分数为基准）的钒钨钛催化剂（Ce1V1W7/Ti）表现最佳,其在全温度（260~400 ℃）段的脱硝活性均优于改性前,在260 ℃,空速为6×104 h-1的反应条件下,NOx脱除率从79.0 1%增加至99.19%,在含有H2O、SO2的气氛中,其NOx脱除率从58.33%升至74.55%。Ce掺杂降低了催化剂表面的氧空位形成能,改变了催化剂表面的酸位强弱,强化了SO2在催化剂表面的吸附,SO2中毒后的催化剂表面会沉积硫酸铵盐,在H2O的协同作用下,Ce掺杂后催化剂表面更易沉积硫酸铵盐,这是催化剂失活的主要原因。     

Fe-Mn-CeOx/AC@CNTs催化剂低温协同去除NO和氯苯

以活性炭@碳纳米管（AC@CNTs）为载体，通过浸渍法制备了Mn-CeOx/AC@CNTs催化剂，并考察了铁物种的引入对Mn-CeOx/AC@CNTs催化剂同时去除一氧化氮（NO）和氯苯（CB）活性的影响。利用SEM、XRD、Raman、FTIR、XPS、H2-TPR等方法对催化剂的理化性质进行了表征。结果表明，Mn物种进入CeO2的晶格中形成Mn-Ce固溶体促进氧空位的生成，而催化剂表面存在丰富的C—H基团和含氧基团有利于提高催化剂的低温催化活性。与Mn-CeOx(1:7)/AC@CNTs（n(Mn):n(Ce)=1:7）催化剂相比，Fe-Mn-CeOx(1:7)/AC@CNTs催化剂表面吸附氧的含量和酸位点数量显著增加，使其具有良好的氧化还原性能和表面酸性。Fe-Mn-CeOx(1:7)/AC@CNTs催化剂在整个温度窗口表现出最高的催化活性，其中，在225～300 ℃范围内，NO转化率达到90%以上，300 ℃时，CB转化率>90%。此外，当CB存在时，300 ℃时，Fe-Mn-CeOx(1:7)/AC@CNTs催化剂的NO转化率依然能达到95%。     

甲烷磺酸亚铈催化合成月桂酸酯的研究

合成了甲烷磺酸亚铈,用热重和红外对其进行表征.并以甲烷磺酸亚铈为催化剂,研究其催化月桂酸与正丁醇酯化反应中各种因素对酯化率的影响.优化试验结果为醇与酸的摩尔比为1.11,Ce(CH3SO3)3·4H2O的用量为酸的摩尔分数的0.25%,80℃～85℃反应2.5 h,环己烷5 mL为带水剂,酯化率可达98.9%.结果表明甲烷磺酸亚铈的催化活性远远高于Ce(SO4)2·4H2O、CeCl3·7H2O及其他Lewis酸催化剂.用甲烷磺酸亚铈作催化剂合成其他月桂酸酯,酯化率均在95.0%以上.     

溶胶凝胶自蔓延法制备过渡金属离子掺杂NH3-SCR催化剂性能研究

采用溶胶凝胶自蔓延方法制备出不同过渡金属掺杂的R-MnOx(R=Ce、Co、Cr、Cu) NH3-SCR催化剂.采用TG-DSC、BET、XRD等进行催化剂结构与性能的表征,并采用NH3-SCR模拟测试装置对R-MnOx进行催化效果测试.结合第一性原理对催化剂的吸附性能进行模拟,进一步解释不同掺杂元素对催化剂的影响.结果 表明,Ce、Co掺杂能够有效降低MnOx吸附能势垒,增加NO与NH3气体分子与催化剂活性位点的接触机会,从而提高催化剂的低温催化活性.Ce-MnOx具有较低的结晶度和更大的比表面积,也增大了气体分子与催化剂活性位点的接触机会.因此,Ce-MnOx具有最好的NH3-SCR催化效果,在120 ～240℃范围内NO的转化率能达到88％以上.     

Ce掺杂对Mn-Co/TiO_2催化剂催化氧化NO的影响

采用浸渍法制备Mn-Co-Ce/TiO2催化剂,考察Ce掺杂对催化剂催化氧化NO情况的影响。研究表明:在550℃焙烧下,Ce/Ti掺杂比为0.15时,催化剂具有最高的催化氧化活性。反应温度为250℃时,NO转化率可以高达85%;150℃时,转化率也可达到50%以上。BET与XRD结果表明,Ce掺杂改变了催化剂的比表面积、孔容积,并提高了活性组分的分散度。SO2和H2O的共同加入,使催化活性降低,发生不可逆中毒,但转化率在60%左右。     

新型铬钴复合氧化物中低温选择性催化NOx还原及原位机理研究

采用固相法合成系列铬钴复合氧化物催化剂,该催化体系在中低温[(180~300)℃]下具有优异的氨选择性催化氮氧化物还原活性,其中,Cr(0.5)-Cr Ox催化剂在空速50 000 h-1、反应温度200℃和220℃条件下,NOx转化率达100%。采用原位DRIFIS研究催化剂表面吸附物种以及催化机理,在反应温度220℃考察Cr(0.5)-Co Ox催化剂表面NH3与NO的吸附态形式和NH3-SCR反应过程中中间态及其反应机理。结果表明,Cr(0.5)-Cr Ox催化剂上NH3吸附在L酸位,也能吸附在B酸位,但只与气态的NOx反应,生成中间体NH2NO,再进一步反应,最终生成N2与H2O。吸附态的NOx不参与SCR反应,反应遵循Eley-Rideal机理。     

固体超强酸SO42-/Fe2O3催化法合成乙酸异戊酯

用(NH4)2SO4·Fe2(SO4)3·24H2O直接焙烧的方法制备了固体超强酸催化剂SO2-4/Fe2O3,并催化合成了乙酸异戊酯,考察了固体酸催化剂的最佳合成条件.实验表明最佳焙烧温度为550℃,最佳焙烧时间为4h.当催化剂用量为2g,乙酸、异戊醇物质的量的比为2.61,回流时间2h时,乙酸转化率为76.6%.     

低温等离子改性对Ce/TiO2-Al2O3脱硝性能的影响

采用等体积浸渍法制备了的Ce/TiO2-Al2O3(不同摩尔比例)脱硝催化剂.通过性能比较,将最佳Ti/Al比例(2:1)的Ce/TiO2-Al2O3催化剂用于低温等离子体改性.改性后催化剂的整体性能包括:NO转化率、N2选择性、稳定性都有了一定的提高,改性前后催化剂在350℃左右的最佳脱硝效率分别为:90.23％,95.67％.此外,由催化剂抗碱金属实验结果可知,改性后的催化剂有更好的抗性,改性前后脱硝效率分别为63.25％,70.54％.并且由XRD,BET,FTIR,UV-vis,NH3-TPD,SEM,XPS,H2-TPR一系列表征结果可知,催化剂整体性能的提高与等离子体改性有关,而且低温等离子体改性作用主要体现在两方面:第一、增加了催化剂表面的Ce3+物种,促进了化学吸附氧的生成;第二、催化剂先经等离子体改性再煅烧,有利于增加催化剂表面的Bronsted酸与Lewis酸位点.     

Ce/AC低温脱硝催化剂的性能研究

以40％硝酸处理的活性炭为载体,通过浸渍法制备一系列Ce/AC催化剂.采用传统的固定床反应装置,氨气作还原气体,考察了温度、铈负载量、NH3/NO（摩尔比）、氧含量、空速、H2O等不同条件下NO的转化率.实验表明,温度在120℃、Ce的负载量为5％、空速为10000h-1时,催化剂对NO的转化率高达97％,150℃时可达100％.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。