复合型絮凝剂PAC-PAM处理含乳化油废水的试验研究

研究了不同条件下的聚合氯化铝和聚丙烯酰胺复合絮凝剂(PAC-PAM)对含乳化油废水的絮凝效果,并与使用单一絮凝剂的效果进行了对比。通过单因素条件试验研究pH值、PAC:PAM配比、溶液温度和沉降时间等操作条件对PAC-PAM复合絮凝剂处理含油废水效果的影响,从而得到PAC-PAM复合絮凝剂处理含油废水的最优条件及絮凝机理。结果表明:PAC-PAM复合絮凝剂处理含乳化油废水的最佳操作条件为:PAC为30mg/L、PAM为6mg/L、溶液温度40℃、溶液pH值为7和沉降时间30min。以COD去除率代表絮凝效果的好坏,最优条件下的COD去除率达到84.57%。复合絮凝剂处理含乳化油废水的絮凝机理主要是:电中和破乳及高分子链的架桥综合作用。与使用单一絮凝剂PAC或PAM相比,PAC-PAM复合絮凝剂对含乳化油废水的絮凝效果更好。     

阳离子型PAM/PAC复合絮凝剂对活性染料废水的脱色作用

就阳离子型聚丙烯酰胺(PAM)/聚合氯化铝(PAC)复合絮凝剂对活性染料废水的脱色性能进行了研究。加入1mg/LPAM可将PAC的用量从150mg/L减少至100mg/L;PAM阳离子度为50%时,脱色率可达到90%以上,过多的阳离子会导致胶体颗粒重新稳定。单纯的PAC作用下,絮体呈现连续的絮状形态;加入PAM后,絮体具有起伏不平的链网状结构。     

絮凝法处理橡胶促进剂CBS废水的研究

采用絮凝法对橡胶促进剂CBS废水进行絮凝实验,考察了絮凝剂的选择、PAC质量浓度、pH、沉降时间以及温度对絮凝效果的影响,确定了利用PAC处理废水的最佳絮凝条件。结果表明,PAC质量浓度为1. 2 g/L、pH为4、温度为40℃时,COD去除率可达70%。在最佳条件下,PAC与PAM复合絮凝剂处理橡胶促进剂CBS废水是可行的,COD去除率明显优于使用单一絮凝剂。在光学显微镜下观察发现,PAC絮凝形成的絮体与复合絮凝剂形成的絮体形态不同,因此复合絮凝剂的絮凝效果优于单一絮凝剂。当PAM质量浓度为6 mg/L时,沉降时间缩短为15 min,静沉比降至4∶92,COD去除率可高达82%以上,有效地解决了CBS废水难以生物降解的难题。     

PAC和PAM絮凝剂处理PTA工业废水的应用研究

考察了PAC和PAM絮凝剂对PTA废水的处理效果,分析了絮凝剂PAC和絮凝剂PAM投加量对出水浊度的影响。研究结果表明,PAC投加浓度为4～6 mg/L,PAM投加浓度为0.6～0.8 mg/L时,对应出水浊度2 NTU,去除率55%。     

高分子复合絮凝剂对活性印染废水的脱色性能研究

就几种高分子复合絮凝剂对活性染料废水的脱色性能进行了研究.当聚丙烯酰胺(PAM)的阳离子度为50%时,脱色率可达到90%以上,过多的阳离子会导致胶体颗粒重新稳定;1 mg/L相对分子质量为1.2×107的PAM与150 mg/L PAC复合可达到98.2%的最佳脱色效果,分子链过长的PAM分子由于空间位阻效应使颗粒间互相排斥;1 mg/L壳聚糖(CTS)与100 mg/L PAC复合后脱色率即可大于90%,过多的CTS分子因吸附空位的饱和无法发挥作用.通过SEM观察发现在PAC单纯的电中和作用下,絮体呈较为平坦的均匀连续絮状形态.加入有机高分子絮凝剂后,由于分子链的桥联卷扫作用,呈现出不同特点的聚集形态,形成比表面很大的絮体,从而强化对颗粒的吸附和架桥作用.     

阳离子型DF/PAC复合絮凝剂处理活性印染废水

针对印染厂生产废水,以COD和色度为指标,用混凝试验方法,研究了碱化度为1.6的聚合氯化铝(PAC)和黏度为560mPa·s的双氰胺-甲醛缩聚物(DF)以及阳离子型DF/PAC复合絮凝剂对活性印染废水的处理效果.考察了絮凝剂的沉降效果和絮凝剂的投加量及投加方式对絮凝脱色效果的影响,探讨了废水pH值对阳离子型DF/PAC复合絮凝剂絮凝脱色性能的影响.结果表明,DF/PAC可有效地去除印染废水中的COD和色度,当pH为6～9、沉降时间为35min、投药量为1.0mg/L时,去除效果最佳,COD去除率≥90%,脱色率≥99%;相对于PAC和DF,DF/PAC产生的絮体大而密实,沉降速度快、产生污泥量少,药剂用量少,出水水质为:COD<80mg/L,色度<30倍.     

多糖生物絮凝剂在污水处理中的应用

将根瘤菌CFCC2272所产的胞外多糖制备成生物絮凝剂,与PAM和PAC分别应用于高岭土废水、刚果红印染废水的絮凝处理.对高岭土废水的处理,生物絮凝剂的最佳投药量略高于PAC及PAM,为12 mg/L;最适pH值范围较广,为4～12.对于刚果红印染废水的处理,生物絮凝剂的最佳投药量为100 mg/L,最适pH范围为6～12.     

复合絮凝剂对染料废水的脱色作用

用羧甲基壳聚糖(CMCTS)复合聚合氯化铁(PFC)对相对分子质量较小的活性染料模拟废水进行脱色处理.结果表明,引入PFC作为助凝剂的脱色效果优于单纯使用CMCTS.采用此复合絮凝剂处理染料废水的最佳条件为pH=5,CMCTS和PFC的投加质量浓度分别为90 mg/L和2 mg/L.在此优化条件下,染料废水的脱色率可达93.8%,COD去除率达89.6%.     

絮凝剂PAC和PAM处理洗涤废水的应用研究

以南雄市某洗涤企业综合洗涤废水为研究对象,探讨了PAC(聚合氯化铝)和PAM(聚丙烯酰胺)共同处理该洗涤废水的最佳条件,以COD_(Cr)为指标反映处理效果,通过改变初始pH值、絮凝剂PAC及PAM用量、沉淀时间等因素,测定废水COD_(Cr)浓度,反映处理效果。结果表明:当初始pH值为7,PAC添加量为6 mL,沉淀时间为30 min,PAM添加量为2 mL时,处理效果最佳。     

CTS/PAM/PAC絮凝剂处理造纸废水的应用研究

为了改善传统絮凝剂聚合氯化铝/聚丙烯酰胺(PAC/PAM)的絮凝效果,本课题研究了壳聚糖/聚合氯化铝/聚丙烯酰胺(CTS/PAM/PAC)复合絮凝剂的制备方法,考察了絮凝剂用量、pH值、搅拌速率和搅拌时间等因素对造纸废水CODcr和浊度去除效果的影响.结果表明:当复合絮凝剂中CTS、PAM和PAC用量分别为12 mg/L、60 mg/L和200 mg/L时,在pH值为7.2、搅拌速率和搅拌时间分别为80 r/min和8 min条件下,絮凝效果最好,CODcr与浊度的去除率分别为53.9％和98.6％.与PAC/PAM混合絮凝剂相比,CODcr与浊度的去除率分别提高了13.2％和5.9％,药剂成本下降了21.1％,因此,CTS/PAM/PAC絮凝剂具有明显的环境效益与经济效益.     

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。