聚四氟乙烯中空纤维气态膜法浓海水提取溴素

以浓海水为含溴原料液,NaOH溶液为吸收剂,考察了用聚丙烯（PP）、聚偏氟乙烯（PVDF）和聚四氟乙烯（PTFE）3种材料制作的微孔疏水中空纤维气态膜组件从浓海水中提溴的性能和使用寿命。实验结果表明PTFE中空纤维膜具有更高的传质系数和更强的耐溴氧化能力,更适合用于浓海水提溴。进而考察了各种操作条件对PTFE气态膜组件传质系数K和提溴率η的影响以及该组件的长期操作稳定性。实验结果表明：K随温度增加而增大,随料液中NaCl含量的增大而略有减小,料液流速和含溴量、吸收液的流速和吸收剂浓度对传质系数影响不大。PTFE膜组件在连续运行的3个月内表现了良好的操作稳定性,为PTFE中空纤维气态膜法提溴工艺的工业化应用提供了技术基础。     

盐酸作吸收剂用于气态膜法从废水中脱除/回收氨氮

考察了盐酸作吸收剂时用气态膜技术从水溶液中脱氨的可行性,鉴于盐酸的挥发性,着重考察了不同料液氨水浓度下气态膜过程可以稳定操作时所对应的吸收液中盐酸的临界浓度。在此基础上,研究了料液氨氮浓度、料液流速、吸收液流速、吸收液盐酸浓度和操作温度等操作参数对膜传质性能的影响,并考察了该工艺的长期操作稳定性。实验结果证明,气态膜脱氨过程可采用一定浓度的稀盐酸溶液作为吸收剂,并可通过向吸收液中不断添加浓盐酸的方式得到浓度为>15%的氯化铵溶液。在料液浓度为2000 mg/L、吸收液盐酸浓度为2%、操作温度为25 ℃的操作条件下,中空纤维膜组件持续稳定运行了650 h以上,总传质系数保持在4.25×10?6 m/s左右。用盐酸作吸收剂时废水中氨氮可脱至15 mg/L以下,符合国家环保标准。这表明采用盐酸作吸收液用气态膜法从废水中脱除回收富集氨氮是可行的。     

错流式中空纤维膜接触器脱除水中氨氮的实验研究

采用矩形错流式中空纤维膜接触器进行脱除水中氨氮的实验研究,考察了操作条件对脱氨过程总传质系数(K)的影响。结果表明,料液p H和料液流速对总传质系数影响显著。料液p H=10.5时,料液流速由0.016 m/s增大到0.051 m/s,而硫酸浓度对总传质系数影响较小。实验获得了较高的K值,最高可达1.96×10-5 m/s。在最佳的脱氨条件下连续运行10 h,料液氨氮质量浓度由1 000 mg/L降至0.11 mg/L,具有广阔的工业化前景。     

PVDF膜接触器脱除回收垃圾渗滤废液中的氨氮

应用PVDF膜接触器处理垃圾渗滤废液,考察了料液pH、流量和温度等对膜组件传质性能的影响.实验结果表明：废液中的氨氮可被脱除至150· 10-4％以下,同时还可得到浓度为26％左右的硫酸铵溶液.提高料液pH和温度可促进氨的传质,而废液流量对传质系数影响较小.     

PVDF膜接触器脱除回收垃圾渗滤废液中的氨氮

应用PVDF膜接触器处理垃圾渗滤废液,考察了料液pH、流量和温度等对膜组件传质性能的影响。实验结果表明:废液中的氨氮可被脱除至150·10-4%以下,同时还可得到浓度为26%左右的硫酸铵溶液。提高料液pH和温度可促进氨的传质,而废液流量对传质系数影响较小。     

不同中空纤维膜材料对烟气中二氧化硫的吸收性能影响

膜法烟气脱硫能耗低、传质面积大、分离效率高,可以有效地解决传统塔器内的液泛、漏液、夹带等问题。本文采用自制的中空纤维膜接触器,通过改变烟气流量、水流量和水温对比了聚四氟乙烯（PTFE）、聚偏氟乙烯（PVDF）和聚丙烯（PP）这3种中空纤维膜对烟气中二氧化硫的吸收性能,并通过电镜和接触角仪表征,对比了3种膜的参数和疏水性。结果表明：在不同烟气流量、水量和水温下,3种膜的吸收性能都表现为PTFE＞PP＞PVDF,120min时二氧化硫吸收浓度,PTFE最大,是PP的1.68倍,是PVDF的4.62倍;烟气流量的改变对二氧化硫的吸收浓度有显著影响,当烟气流量由60mL/min提高到140mL/min时,120min时PTFE膜二氧化硫的吸收浓度提高了2.14倍;影响膜性能的主要因素为疏水性,PTFE浸泡前后的表面接触角为105°和97°,疏水性远大于PP和PVDF。PTFE中空纤维膜孔径大、孔隙率高,具有极强的疏水性,在烟气脱硫及相关吸收过程中表现出较好的应用前景。     

气态膜处理五氧化二钒废水中氨氮的中试研究

气态膜吸收是近年来兴起的一种高效的膜分离技术,由于具有处理成本低,运行操作方便,不产生二次污染,不改变被分离物质形态,可回收挥发性化学物质等优点,在环境保护领域里显示出广阔的应用前景。以某五氧化二钒生产厂的实际生产废水为处理对象,采用疏水性的聚丙烯(PP)中空纤维气态膜进行了废水中氨氮的脱除和回收中试实验。实验结果表明,采用气态膜工艺,将废水pH调至11~12,采用稀硫酸做为吸收剂,在适当的跨膜压差、停留时间和流速条件下,氨氮的回收率可达98%以上。     

气态膜法回收垃圾渗滤液氨氮技术进展与机理探讨

目前传统生物脱氮工艺中需投加大量碳源用于提高垃圾渗滤液的C/N，且随着填埋龄增加，C/N严重失衡，将导致脱氮成本偏高。氨吹脱(汽提)法、鸟粪石法等脱氮技术已实际应用在垃圾渗滤液脱氮处理中，但总体应用效果均有待提高。气态膜法是一种新型低能耗、高效率的氨氮资源回收技术。综述了气态膜法在高氨氮垃圾渗滤液处理中的应用；并以双膜理论为基础，推导出适用于气态膜法的氨传质机理。气态膜法氨传质过程可归纳为串联阻力模型，即总传质阻力为料液侧传质阻力和气态膜内传质阻力之和，料液侧传质系数(K_f)与气态膜类型及其组件形式、Re和Sc等参数相关，气态膜膜内传质系数(K_m)取决于气态膜的孔径、孔隙率、孔径曲折度以及厚度等参数；增大料液流速可促进NH₃在料液侧至料液边界层以及料液边界层向膜表面的扩散与传质，从而大幅提高总传质系数(K_OV)。简言之，气态膜法可用于垃圾渗滤液、沼液等高氨氮废水脱氮处理与资源化利用，气态膜回收产物可作为化工原料和农业氮肥。     

聚四氟乙烯中空纤维膜首次成功用于高氨氮废水处理

<正>近日,中国科学院大连化学物理研究所曹义鸣团队开发的聚四氟乙烯(PTFE)中空纤维膜接触器技术,成功应用于提钒废水中高浓度氨氮的脱除项目。废水处理量50吨/天、进水氨氮浓度为2 000～5 000 mg/L,设计的出水氨氮浓度为10 mg/L。工业项目由该所和南京碧盾新膜技术有限公司提供PTFE膜组件及工艺流程设计,攀枝花碧源科技有限公司     

真空膜蒸馏法处理含甲醛废水试验研究

采用聚四氟乙稀(PTFE)膜和聚偏氟乙稀(PVDF)中空纤维微孔膜组件对含甲醛废水进行膜蒸馏处理,研究影响甲醛通量的诸因素,如料液温度、浓度、流速等,通过试验得出用PTFE膜和PVDF膜处理甲醛废水的最佳条件,即PVDF膜的膜分离效率在50℃达到最大值,为86.27%,而PTFE膜在60℃达到最大值,为97.1%.由于PTFE膜的疏水性较PVDF膜强,因此在相同进料条件下,PTFE膜分离效率和离子去除率都较PVDF膜高.料液温度为60℃,PTFE膜的膜通量约为24×10-3 kg·m2·h-1.采用膜蒸溜法,浓度高达0.9mg·mL-1的甲醛废水溶液经处理后可降至0.03mg·mL-1以下,达到国家规定的排放标准.     

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。