Fenton法氧化降解聚乙烯醇的研究

本文采用Fenton氧化法处理浓度为1.5g.L-1的聚乙烯醇(PVA)模拟废水,研究了反应时间、溶液的初始pH值、H2O2投加量、H2O2/Fe2+投加比和反应温度等因素对PVA氧化降解的影响。结果表明,在pH值为4、H2O2/Fe2+的摩尔比为10∶1,温度40℃,时间为40min,H2O2投加量为7g/100mL时,PVA的降解率可达93.28%。     

超声/H2O2工艺降解水溶液中氯苯的实验研究

研究在超声／H2O2联合作用下,超声场中氯苯的降解过程,考察了超声时间、氯苯浓度、pH值、氧化剂H2O2的浓度等因素对降解率的影响。实验结果表明：氯苯的初始浓度与降解率基本成线性关系;pH值的变化对降解率影响不大,超声波／H2O2联合工艺与单独超声作用相比,降解率有了较大的提高,处理100min后,可以获得87％的降解率,其降解过程符合一级动力学方程。     

US/Fe~(3+)/H_2O_2体系超声催化降解甲基橙的研究

采用US/Fe3+/H2O2体系超声催化降解甲基橙,考察了超声波功率、Fe3+初始质量浓度、H2O2用量、甲基橙溶液的初始质量浓度及初始pH值对超声催化降解甲基橙的影响,初步探讨了其降解动力学规律。结果表明,US/Fe3+/H2O2体系能有效降解甲基橙,且超声波与Fenton试剂对甲基橙废水的降解存在强烈的协同作用;在pH=3、超声波功率500 W、Fe3+和H2O2的初始质量浓度分别为30 mg/L和150 mg/L时,对含30 mg/L的甲基橙溶液降解120 min,其去除率达到99.5%;甲基橙的超声催化降解符合一级反应动力学规律,且甲基橙的一级反应速率常数随其初始质量浓度增大而降低。     

超声化学降解水溶液中甲基橙的研究

基于所建立的实验装置,以甲基橙为研究对象,研究了超声降解的规律。实验研究了甲基橙的初始浓度、超声降解时间、初始溶液的pH值和H2O2、Fe^2＋等自由基促进剂等因素对降解效果的影响。结果表明,初始浓度为5mg／L,反应时间为90rain,初始溶液的pH值为2,加入H2O2、Fe^2＋自由基的最佳降解条件下,甲基橙的降解率可达到94．7％。     

有机溶剂中4,4′-二溴联苯的超声降解

研究了有机溶剂中4,4′-二溴联苯(4,4-′DBB)的超声降解.考察了初始质量浓度、处理时间及添加氧化剂(H2O2)和盐(NaC l)后的联合作用对降解率的影响.采用超声频率20 kHz、固定声强0.16W/cm2的超声波作用一段时间,结果表明:初始质量浓度越大,降解率越低;超声时间越长,降解率越高.单独超声降解8 mg/L 4,4-′DBB溶液600 m in,降解率可达16.0%.而加盐超声240 m in,10 mg/L 4,4-′DBB溶液的降解率可提高到12.1%,符合一级反应规律,一级反应常数为-5.231 18×10-4m in-1.超声与过氧化氢(US/H2O2)联合作用180 m in,2 mg/L 4,4-′DBB溶液的最终降解率可达到43.1%.     

Fe2O3/H2O2类芬顿法处理阴离子表面活性剂废水的试验

该文采用Fe2O3/H2O2类芬顿试剂处理阴离子表面活性剂——十二烷基苯磺酸钠(SDBS),研究了H2O2浓度、Fe2O3投加量、pH值及反应温度对处理效果的影响,结果表明SDBS的降解率随温度的升高而升高;当H2O2/Fe2O3=1.568(物质的量比)时体系具有较高的降解率;pH对体系降解率影响不大,在2-10的范围内降解率均较高;Fe2O3/H2O2非均相体系类F.nt.n试剂和Fe2+/H2O2均相体系Fenton试剂的降解效果相差不大,但前者具有pH范围宽,易分离,不产生二次污染的特点.     

超声波降解低浓度邻硝基苯酚废水的研究

分别采用超声波(US)和US/H2O2降解含低浓度邻硝基苯酚(ONP)的水溶液,考察了ONP初始浓度、US频率和功率、溶液的pH值、降解过程的搅拌、H2O2的加入量以及H2O2投加方式等各种影响因素对ONP降解效果的影响。试验结果表明:ONP的超声波降解反应属于表观一级动力学反应;随着ONP初始浓度的增加,ONP的降解速率和去除率均减小;提高超声波的频率和功率可促进ONP的降解;溶液pH值的降低可提高ONP降解速率;超声降解过程中的搅拌会降低ONP降解速率;H2O2的投加则显著提高了ONP的去除率,并对其进行了理论分析与探讨。     

微波/过氧化氢降解水中苯酚

研究了在微波/H2O2辐射下苯酚溶液降解率,考察了影响微波/H2O2辐射降解苯酚溶液的各种因素.试验结果表明:苯酚降解率与溶液初始浓度、pH值、微波辐射时间和微波辐射温度等因素有关.随着微波温度的增加苯酚降解率呈线性增加.且初始溶液浓度愈高,苯酚降解量愈高.微波辐射时间愈长,苯酚降解率愈高.微波对苯酚的降解过程符合表观...     

超声波协同Fenton氧化降解PVA及其动力学分析

采用超声波协同Fenton氧化降解聚乙烯醇(PVA)模拟废水,并与2种方法单独作用进行了对比。结果表明,增加反应时间和超声功率在一定程度上有助于提高PVA的去除率;反应的最佳pH应该控制在4.0左右;随着H2O2/COD(质量浓度比)的增加,PVA去除率有很大提高,H2O2/Fe2+(物质的量比)最佳值为8。通过分析不同反应时间下降解产物分子质量分布情况和GC-MS检测结果,推测反应将大分子氧化成中小分子的过程。动力学分析结果表明,超声波协同Fenton降解PVA符合一级反应动力学规律,从k值模型方程可看出H2O2/COD对反应的影响最大。     

超声/过氧化氢联合降解苯酚废水的研究

采用超声波/过氧化氢(US/H2O2)工艺对苯酚模拟废水进行了降解,考察了处理时间、苯酚溶液的初始pH值、初始浓度、反应温度等对降解效果的影响.实验结果表明:在单一超声波辐照或过氧化氢氧化下苯酚的降解率低,而两者联合降解效果明显提高,表明存在协同效应.在苯酚废水初始浓度为50mg/L、初始pH值3.01、反应温度25℃、处理时间180min在US/H2O2共同作用下,苯酚降解率为52.2%.苯酚在US/H2O2工艺中的降解反应符合表观一级反应动力学.     

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。