粉煤灰沸石碱性活化方法研究

粉煤灰是一种主要成分为硅铝酸盐的工业废弃物,粉煤灰沸石合成转化是其高值化应用的一个发展方向。利用碱性试剂活化粉煤灰是粉煤灰合成沸石的重要途径,研究比较了粉煤灰碱性活化合成沸石的干法和湿法工艺,包括水热法、高温熔融水热法和盐熔法的现状、特点、合成机理,并对碱性活化剂氢氧化钠、硅铝比、煅烧条件等影响因素做了分析研究。     

粉煤灰合成沸石的研究进展

本文综述了用粉煤灰合成沸石的方法,详细叙述了传统碱性溶液下粉煤灰转化成沸石实验过程,强调在不同的实验条件下可以合成不同类型的沸石.粉煤灰合成沸石主要采用两种方法:直接转化法和两步转化法.文中还讲述了不同种类沸石在废水处理中表现出的潜能,根据文献中的实验数据表明从废水中去除重金属离子是沸石的主要性能之一,不同种类的沸石在废水处理中吸附重金属离子能力不同.并为粉煤灰合成沸石提出新的发展方向.     

粉煤灰沸石合成转化的研究

综述了以粉煤灰为原料合成沸石的方法,包括传统的湿法合成-水热合成法,干法合成-碱熔法、盐熔法,二步合成法（两步水热合成法,碱熔水热混合法,微波辐射合成法,晶种添加法）等工艺,分析了影响粉煤灰沸石转化的各种因素,如固液比、SiO2/Al2O3比例、反应温度、晶化时间等。     

粉煤灰基沸石分子筛的合成及应用进展

煤炭在燃烧利用过程中产生大量的粉煤灰。我国粉煤灰产量高居世界第1位,由于综合利用率只有70%,仍有大量粉煤灰露天堆存,造成严重的环境污染和资源浪费。消除粉煤灰的环境污染、提高其资源化利用率对我国循环经济的发展具有重要的现实意义。我国粉煤灰的利用由早期的粗放型规模化利用逐渐向精细型高值化利用转变。由于粉煤灰中富含硅铝元素,以粉煤灰为原料合成沸石分子筛是近年来粉煤灰高值化利用的研究热点。从4个方面对粉煤灰基沸石分子筛的合成及应用展开论述。首先,介绍了粉煤灰的形成、物化性质及其危害和治理利用现状。粉煤灰是一些矿物组成不同、形态不同的颗粒的机械混合物,其性质与原煤的成分、产地和燃烧方式有关。而粉煤灰的特性是决定其综合利用方式的关键。其次,论述了粉煤灰的3种主要活化方式,包括机械活化、水热活化和碱(盐)融活化。粉煤灰中的硅铝元素主要以非晶矿物玻璃体形式存在,其表面是致密的玻璃质外壳,粉煤灰合成沸石分子筛的关键问题是如何使硅和铝被充分活化,并得到有效利用。相比于机械研磨活化和碱(盐)熔融活化,水热活化有更高的活化效率和较低的能耗。第3部分论述了粉煤灰基沸石分子筛放入水热合成方法,重点介绍了直接水热合成法、碱融-水热合成法、微波/超声波-水热合成法、晶种法和转晶法。粉煤灰合成沸石分子筛一般均基于水热合成过程,多步水热处理可提高产物纯度,辅以超声、微波、碱熔融和添加晶种等方法可提高产率、晶化速率和结晶度。转晶法可极大拓展粉煤灰基沸石的骨架类型和酸性位,是更有利的粉煤灰基沸石分子筛的制备技术。最后,概述了粉煤灰基沸石分子筛的应用。粉煤灰基沸石分子筛的应用尚处于探索阶段,主要用于环境治理领域,包括工业废水中重金属离子的吸附脱除、大气污染物的吸附脱除以及温室气体CO2吸附。     

Na_2CO_3活化粉煤灰合成沸石及去除Cu~(2+)性能

以粉煤灰为基质材料,Na2CO3为碱性活化试剂,比较了高温熔融法、水热法和加压水热法合成沸石对铜离子的去除效果。研究了水热温度及压力、Na2CO3浓度、液固比、水热时间等因素对Na2CO3碱性活化粉煤灰的影响。结果表明,加压水热法合成的沸石对铜离子的吸附效果最好,温度90℃,自生压0.038 MPa,Na2CO32.0 mol/L,液固比10∶1、水热时间2 h时合成的沸石对初始浓度200 mg/L的铜离子的去除率可达92%,XRD表征说明合成的沸石为Na P型。     

Na_2CO_3活化粉煤灰合成沸石及去除Cu~(2+)性能

以粉煤灰为基质材料,Na2CO3为碱性活化试剂,比较了高温熔融法、水热法和加压水热法合成沸石对铜离子的去除效果。研究了水热温度及压力、Na2CO3浓度、液固比、水热时间等因素对Na2CO3碱性活化粉煤灰的影响。结果表明,加压水热法合成的沸石对铜离子的吸附效果最好,温度90℃,自生压0.038 MPa,Na2CO32.0 mol/L,液固比10∶1、水热时间2 h时合成的沸石对初始浓度200 mg/L的铜离子的去除率可达92%,XRD表征说明合成的沸石为Na P型。     

粉煤灰为原料碱熔融-超临界水热合成沸石的研究

以粉煤灰为原料,采用碱熔融-超临界水热法合成粉煤灰沸石。考察了碱熔融预处理过程中碱的种类、焙烧温度、碱灰比对粉煤灰活化效果的影响;研究了粉煤灰沸石合成过程中晶化温度、碱液浓度、晶化时间、液固比和硅铝摩尔比等对粉煤灰沸石生成的影响,优化合成条件。结果表明:Na_2CO_3为活化剂,碱灰比为1.2∶1,850℃下焙烧3 h对粉煤灰的活化效果最好;经碱熔融预处理的粉煤灰与水混合在超临界水热条件下可合成钙霞石,且最佳晶化条件为加蒸馏水,液固比为5∶1,晶化温度为400℃,晶化时间为5 min,硅铝摩尔比为2.5∶1。     

粉煤灰为原料水热合成ZSM-5沸石的工艺条件

以工业废弃物粉煤灰为初始原料,经酸处理除杂、碱处理活化后,采用常规水热法合成高纯ZSM-5沸石。考察酸处理过程的温度、时间和酸浓度等对酸浸取效果的影响,以及碱处理过程的焙烧温度和碱灰质量比等对碱熔活化的影响,采用XRF、XRD、SEM以及N2吸附-脱附等手段对各阶段样品进行表征。结果表明,盐酸处理可以除去粉煤灰中氧化钙、氧化铁等绝大部分碱性氧化物杂质,最适宜酸处理条件下所得粉煤灰中氧化硅和氧化铝质量分数之和由51.51%上升到处理后的85.37%;以最适宜高温氢氧化钠碱熔活化条件下所得活性硅铝溶液为原料,水热合成类似球状结构并具有较高比表面积和相对结晶度的高纯ZSM-5沸石,进而获得粉煤灰水热合成ZSM-5沸石的最佳工艺条件。     

低温煅烧粉煤灰合成沸石

以粉煤灰为原料,研究在碱性水热条件下的水热时帆煅烧温度,煅烧后的水热时间对粉煤灰物相的影响。结果表明在水热温80℃,水热4d,合成含P型沸石和X型沸石的粉煤灰沸石A;在400℃煅烧后,全部莫来石和部分石英转变为可容的硅铝酸盐;煅烧后的试样水热12h,合成含A型沸石和F型沸石的粉煤灰沸石B。对粉煤灰沸石A、粉煤灰沸石B、天然沸石和粉煤灰吸附性能进行了研究,结果表明：合成的粉煤灰沸石B吸附能力最好,吸附率为86．83％。     

微波辅助加热粉煤灰水热合成沸石的最佳条件

以火力发电厂粉煤灰为原料,微波辅助加热水热合成沸石,并用阳离子交换容量(CEC)检测粉煤灰沸石合成效果.将微波辅助加热合成与同等条件下的常规水热合成进行比较,探讨微波辅助合成沸石中的影响因素及最佳条件.微波条件下影响粉煤灰合成沸石的种类及合成效果的主要因素有:粉煤灰的组分、温度、时间、活化剂种类、碱浓度、液固比、微波催化等;微波合成最佳条件为:120℃、40 min、NaOH浓度2 mol/L、液固比2.5.     

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。