超声波结合复合絮凝剂强化生物污泥脱水研究及其作用机理

研究了超声波结合复合絮凝剂促进剩余生物污泥脱水及其作用机理。实验结果表明，复合絮凝剂PAM—PAFC的投加比（质量比）为1：1、投加量为污泥干基7％。时，其絮凝效果优于单一絮凝剂，再经20kHz、400W/m^2超声处理2．5min后，污泥体积缩小86％左右，含水率可降至79％，比无超声作用时污泥干基含水率减少7％左右。通过电镜观察发现，小功率超声可促进污泥中小团块的碰撞，增加污泥的絮凝性；投加PAFC后，污泥絮体呈现较为平坦的均匀絮状形态，存在孔洞；再投加PAM后，絮体具有起伏不平的链网状结构，形成比表面较大的复杂形体的絮体，脱水效果优于单独投加PAFC；再经超声处理后，污泥絮体比未加超声时团聚性增强，孔洞增大，脱水性能更佳，脱水效果优于单独投加PAFC—PAM。     

超声波-复合絮凝剂对石化厂剩余污泥脱水的研究

以污泥含水率为考察指标,研究了超声波-复合絮凝剂对石化厂剩余污泥脱水效果的影响.实验结果表明,复合絮凝剂的脱水效果优于单一絮凝剂;污泥采用复合絮凝剂PAM-PAFC进行絮凝脱水,在投加质量浓度190 mg/L、m(PAM)∶m(PAFC)=1∶1条件下,再经20 kHz、400 W/m2超声处理2.5 min后,污泥含水率从97%降至79%,污泥体积缩小86%左右,比仅投加PAM处理时污泥含水率降低5%左右.可见,超声波-复合絮凝剂可以强化污泥脱水,在提高污泥脱水效果的同时,减少了有机絮凝剂PAM的用量,降低了污泥处理成本.     

超声波或生石灰单独及联合作用对污泥脱水性能的影响

研究了超声处理时间和生石灰添加量对污泥脱水性能的影响。超声波单独对污泥进行处理时,超声3 min后污泥的沉降性能最好。但是污泥经超声波处理后又能释放大量的胞外聚合物,增加污泥离心出水的COD,使出水水质变差。CaO对污泥单独处理时,采用10‰的投加量可以显著改善污泥的脱水性能。超声波和CaO对污泥联合处理时,以1 min的超声波处理时间和6‰的CaO投加量为最优条件,在保证污泥离心脱水效率的前提下,不仅减少了CaO的投加量,还能降低污泥离心出水的COD,改善出水水质。     

超声波联合高分子絮凝剂对污泥的调理研究

试验以毛细吸水时间(CST)和离心后污泥含水率作为污泥脱水性能指标,探讨了超声波与高分子絮凝剂阳离子瓜尔胶(CGG)及聚丙烯酰胺(PAM)联合作用对污泥脱水性的影响。结果表明,单独超声波调理污泥,当超声频率为20 Hz,功率为60 W时,最佳作用时间为20 s;超声波与CGG联合调理污泥,当CGG投加量为900 mg/L时,CST由原污泥的470 s降低到76 s,污泥离心含水率由原污泥的88.3%降低到75.3%;超声波与CGG+PAM联合调理污泥,当CGG和PAM投加量分别为300、120 mg/L时,CST和污泥离心含水率均明显降低,分别降低到18 s和58.8%。     

城市污泥调理过程中调理剂的应用比较研究

研究了聚丙烯酰胺--硫酸铁复合调理剂[PAM-Fe2(SO4)3]对活性污泥的脱水性能的影响,考察了投加量、配比等对污泥比阻的降低和滤液的浊度和COD去除的影响.并与聚丙烯酰胺(PAM)、PAC、硫酸铁、硫酸铝(分别单独加入)等絮凝剂的脱水效果进行比较,结果表明,复合调理剂的效果比单一调理剂的效果好,当PAM(1%)和...     

无机混凝剂与壳聚糖联合调理对污泥脱水的影响

研究了无机混凝剂(PAFC和PAC)与壳聚糖(CTS)联合调理对污泥脱水效果的影响。结果表明:联合调理污泥脱水效果明显优于单一混凝剂调理。当无机混凝剂PAFC和PAC投加量(以干污泥量计)分别为60 mg/g,CTS投加量(以干污泥量计)为3.0 mg/g时,PAFC+CTS、PAC+CTS调理污泥比阻比原泥分别降低了87.90%和84.93%,滤饼含水率降到76.3%和76.9%,污泥平均粒径从原来的8.70μm分别增大至59.07μm和54.69μm。相同投加量下,PAFC+CTS联合调理的污泥脱水效果优于PAC+CTS联合调理。     

复合絮凝剂对生活污泥脱水的研究

采用三氯化铁、聚乙烯醇和聚丙烯酰胺三种絮凝剂,考察它们对城市生活污泥的脱水性能。实验结果表明:将三氯化铁与聚乙烯醇以投加比例为4:1时配合使用,其脱水效果均优于单独使用三种絮凝剂的效果。复合絮凝剂用量为干泥量的1.0%时,污泥含水率由94%下降到71%,其体积可缩小为原体积的2%,且滤液澄清度高,透光率达98%。     

絮凝剂投加量及配比对臭氧氧化后剩余污泥脱水特性的影响

臭氧氧化是污泥处理时常用的减量化、资源化技术。过往的研究表明,氧化后的污泥脱水能力变差,需要投加絮凝剂来改善污泥特性。然而,目前关于絮凝剂的最佳投加量与配比的研究较少。研究以上海市某污水处理厂二沉池污泥为对象,通过小试试验研究聚合氯化铝（PAC）与阳离子聚丙烯酰胺（CPAM）投加量与配比对污泥脱水能力的影响,确定了最佳投加量。试验结果表明,臭氧氧化2 h时,投加3%的PAC与0.4%的CPAM,污泥脱水能力达到最佳;超过最佳投加量后,继续投加絮凝剂会造成污泥脱水能力的恶化。研究可为生产中污泥脱水前絮凝剂的投加提供参考。     

超声辅助絮凝强化污染底泥土工管袋脱水减容

将超声处理结合絮凝剂用于土工管袋脱水减容.以滤饼含水质量分数为优化指标,考察超声处理与添加絮凝剂的顺序对脱水性能的影响,并考察了超声处理的最优操作条件.结果表明:先添加絮凝剂再进行超声作用可取得较好的脱水效果,当絮凝剂的投加量(质量分数)为5‰(以干基计),超声波的能量密度为0.5 W/mL,作用时间为10 s,脱水效...     

树叶粉对污泥脱水性能的影响研究

城市污水处理厂通常采用聚丙烯酰胺或铁盐作为污水处理后污泥的脱水调理剂,然而大量化学絮凝剂的使用不利于后期污泥的资源化利用。本研究首次采用树叶粉作为新型"物理调理剂",探究树叶粉及树叶粉-Fe_2(SO_4)_3、树叶粉-PAM联合调理,对污泥脱水性能的影响规律。结果表明,使用树叶粉调理能够在一定程度改善污泥的脱水性能;树叶粉与化学絮凝剂联合调理污泥,能够充分发挥协同作用,脱水效果优于单独使用树叶粉或絮凝剂的调理效果。     

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。