{010}择优取向BiVO4亚微米片的制备及其光催化活性研究

采用丙三醇-水溶液体系,通过调控前躯体的pH值水热合成了具有{010}晶面择优取向的亚微米级片状BiVO4粉体.通过x射线粉末衍射、紫外-可见光漫反射光谱、扫描电镜、透射电镜和高分辨透射电镜等技术对样品的结构和形貌进行表征.分析表明,丙三醇作为定向指示剂,在pH值为4时,制得了{010}择优取向的纯单斜相BiVO4亚微米片.在模拟太阳光照射下,考察了{010}择优取向单斜BiVO4亚微米片与{121}择优取向单斜BiVO4粉体对亚甲基蓝溶液的光催化活性,结果表明,{010}择优取向单斜BiVO4亚微米片具有更高的光催化活性.     

Cu掺杂BiVO4光催化剂的水热合成及其光催化性能研究

以硝酸铋、偏钒酸铵、硝酸铜、氢氧化钠、硝酸等为主要原料,采用水热法合成Cu掺杂BiVO4光催化剂。主要研究了Cu的掺杂量对合成BiVO4光催化剂性能的影响。采用XRD、SEM、BET、紫外-可见分光光度计等检测仪器对合成试样的物相组成、微观形貌、比表面积及光催化性能进行了表征。结果表明:Cu掺杂改变了合成产物的物相组成,产物中出现Bi2O3、V2O5等杂质,并且产物的形貌发生了较大变化。光催化降解亚甲蓝结果表明,随着Cu掺杂量的增加,合成光催化剂的光催化性能呈现先增加后减小趋势,当Cu掺杂量为5 wt%时,合成产物的光催化性能达到最佳,在高压汞灯照射240 min时,对亚甲蓝(10 mg/L)的降解率达87.8%,比同条件下纯BiVO4的光催化效率提高16.4%。     

燃烧法制备BiVO4可见光光催化剂的研究

采用燃烧法合成了稀土掺杂BiVO4光催化剂,通过XRD、FE-SEM、UV-Vis对样品的结构、形貌、光催化性能等进行了分析表征。结果表明:所得样品为单斜相m-BiVO4纯相,平均粒径为50 nm左右;点火温度为500℃时所得Bi0.985Nd0.015VO4光催化效率最佳,光照30 min对亚甲基蓝溶液的降解率达到了90%,比未掺杂的BiVO4光催化效率提高了15%,其降解速率常数为0.07573/min。     

B-Er共掺杂BiVO_4光催化降解金橙Ⅱ的研究

通过柠檬酸络合法合成B-Er共掺杂BiVO4,采用X-射线衍射和扫描电子显微镜表征合成材料的物相、形貌。同时考察溶液的初始浓度、pH、催化剂投加量以及光照强度等因素在可见光的照射下对金橙Ⅱ光催化降解的影响。实验结果表明,在金橙Ⅱ水溶液中,初始质量浓度为15mg/L、pH=3、催化剂投加量为0.015 g、光照距离14 cm,B-Er共掺杂BiVO4对金橙Ⅱ有较好的光催化活性,t为50min后,降解率可达90%以上。     

前驱体对熔盐法合成Bi2WO6光催化剂及其性能的影响

分别以Bi(NO3)3和Na2WO4溶液直接混合所得沉淀、加氨水所得沉淀及Bi(NO3)3×5H2O+Na2WO4×2H2O为前驱体,采用熔盐法合成Bi2WO6光催化剂粉体,研究了不同前驱体所制粉体的物相、形貌,以其为催化剂,在可见光照射下降解罗丹明B溶液. 结果表明,用后二者为前驱体均可得到薄片状纯相Bi2WO6粉体. 加氨水所得沉淀为前驱体所制Bi2WO6粉体的光催化性能最好,在可见光照射下对0.01 mmol/L RhB溶液的降解率在60 min内达99%.     

燃料/氧化剂比值对溶液燃烧法合成BiVO_4光催化性能的影响

以Bi(NO_3)_3·5H_2O和NH_4VO_3为氧化剂,蔗糖(C_(12)H_(22)O_(11))为还原剂和燃料,采用溶液燃烧法合成单斜白钨矿型Bi VO_4粉体。采用XRD、SEM、BET和分光光度计研究了合成粉体的物相组成、形貌和光催化性能。实验结果表明:燃料/氧化剂比值(φ值)对产物形貌和光催化性能影响显著。当φ=2.5时,合成Bi VO_4粉体平均粒径400 nm,且具有较佳的光催化性能,在高压汞灯照射240 min,对亚甲蓝溶液(10 mg/L)的降解率为56.1%。     

水热法制备环境障涂层用硅酸镱粉体的性能研究

采用水热法,以九水硅酸钠和六水氯化镱为原料,以去离子水为介质,以NaF为矿化剂,一步制备出高纯硅酸镱粉体.采用XRD、SEM等手段,研究了水热温度、水热时间等水热条件对硅酸镱粉体的晶相结构以及微观形貌的影响,并对水热法合成硅酸镱粉体的机理进行了分析,最后将粉体压制成块,表征了所制备粉体的热胀系数.结果表明,在230℃-...     

低温固相反应合成Bi2WO6粉体及其可见光光催化性能

以Bi(NO3)3?5H2O和Na2WO4?2H2O为原料,采用固相法直接合成Bi2WO6粉体,研究了反应温度和保温时间对产物物相、形貌及可见光光催化性能的影响. 结果表明,350℃下保温2 h所得粉体含少量Bi2O3和Na2W4O13杂质,但光催化性能最好,可见光照射90 min对0.01 mmol/L RhB溶液的降解率达95%,且经5次循环后光催化活性和化学稳定性良好.     

水热辅助液相合成TiO_2及其光催化性能的研究

本实验中,采用液相沉积与水热合成的的方法,在不同温度条件下制备出TiO_2粉体。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见(UV-Vis)等测试手段,研究了各实验参数条件下的粉体的物相、微观形貌及光催化降解性能。     

一种新的光催化剂Bi36Fe2O57的合成及光催化

报道了一种新型光催化剂Bi36Fe2O57的一种改进的共沉淀合成方法,对不同条件下制备的产物进行了X射线衍射物相分析、扫描电镜形貌分析和光催化性能测试。物相分析表明,缓冲溶液在制备单相彤拍Bi36Fe2O57粉体中起着重要作用。紫外可见漫反射谱图表明,Bi36Fe2O57卵粉体的禁带宽度约为2．06eV,中性缓冲溶液条件下合成的Bi36Fe2O57产物结晶性好,在金卤灯下照射3h,对甲基橙的降解率可达82．7％,在紫外灯下照射2．5h降解率达到99．3％。     

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。