固化/稳定化技术应用于重金属污染土壤修复的研究进展

有害重金属对土壤的污染是全球亟待解决的环境问题。固化/稳定化作为一种相对成熟、经济、有效的土壤修复技术,是目前我国土壤重金属修复的最主要技术。固化/稳定化修复技术通过向土壤中添加固化/稳定化剂,从而将污染物封存或改变其形态,达到减少其迁移性、生物有效性及浸出毒性的目的。本文介绍了固化/稳定化技术修复重金属污染土壤,总结常用的固化/稳定化剂种类及其对重金属污染土壤的修复机理和影响因素,并归纳了几种用于固化/稳定化修复效果评价的方法,最后针对固化/稳定化修复过程中存在的问题,提出今后发展的方向。     

重金属污染土壤固化/稳定化修复技术及设备研进展

针对当前国内外重金属污染土壤固化/稳定化技术研究现状,文章从工艺技术概况、固化/稳定化材料研究及工程设备等三个方面对固化/稳定化技术进行了综述.总结得出我国当前重金属污染土壤固化/稳定化处理普遍存在技术工艺租放、固化/稳定化材料研发薄弱、缺乏高效的一体化设备等问题,同时提出未来研究方向应以固化/稳定化环保高效材料、固化/稳定化自动化程度高的一体化设备为重点.     

重金属污染土壤固化/稳定化修复技术及设备研究进展

针对当前国内外重金属污染土壤固化/稳定化技术研究现状,文章从工艺技术概况、固化/稳定化材料研究及工程设备等三个方面对固化/稳定化技术进行了综述。总结得出我国当前重金属污染土壤固化/稳定化处理普遍存在技术工艺粗放、固化/稳定化材料研发薄弱、缺乏高效的一体化设备等问题,同时提出未来研究方向应以固化/稳定化环保高效材料、固化/稳定化自动化程度高的一体化设备为重点。     

河道污染底泥重金属稳定化药剂研究进展

针对现阶段河道底泥重金属污染严重现象,考察了底泥中重金属的赋存形态,介绍了稳定化药剂种类及其对重金属的修复效果,总结了常规重金属稳定剂的应用现状及不足,展望了新型重金属稳定化药剂的优势及发展方向,以期为河道污染底泥重金属稳定化技术的工程化应用提供借鉴。     

混合氯盐对水泥固化和河道底泥稳定化的影响

以上海市黄浦江流域复兴岛运河段底泥为研究对象,通过添加混合氯盐对河道底泥进行水泥固化稳定化试验,根据固化样品的无侧限抗压强度及重金属浸出毒性试验结果,探究混合氯盐对河道底泥固化稳定化的影响。结果表明,以固化体养护7 d后的抗压强度作为指标,在水泥:干底泥质量比为4:6、含水率为40%的最优条件下,抗压强度可达1.72 MPa;最优配比下,在固化过程中添加2%的混合氯盐(25%氯化钾、30%氯化钠、25%氯化镁和20%氯化钙),底泥固化力学性能可增强52%,其原因可能是水化反应中Cl~-与Ca~(2+)结合生成了氯化钙,再与水泥中的其他物质反应时,可增大固化过程中的固相比例,从而增强力学性能。材料的重金属浸出试验结果表明其重金属稳定效率基本高于90%,说明该方法对重金属污染底泥的稳定化效果良好,但掺杂混合氯盐对金属稳定化的效果影响不大。     

城市河道底泥基于固化/稳定化处置技术的发展瓶颈与可持续利用途径

城市河道严重的内源负荷和面源污染已成为阻碍黑臭河道治理的主要问题。在对底泥固化/稳定化进行长期研究的基础上,以城市黑臭河道生态系统的恢复为目的,针对河道底泥固化/稳定化技术发展瓶颈,探讨了河道底泥固化/稳定化技术适用性,最终提出了城市污染河道底泥的多级目标的可持续利用途径,将固化/稳定化底泥制备成生态砖、吸附材料、吸附陶粒等污水净化材料,运用于生态景石驳岸、雨水花园、人工湿地景观、低影响开发雨水构建系统等中,集防洪效应、生态效应、景观效应和自净效应于一体,既降低内源负荷,又控制面源污染,可为城市黑臭河道的生态恢复提供多维创新的思考模式。     

原址异位固化稳定化技术修复砷、锑污染土壤工程实例

介绍了原址异位固化稳定化技术修复某地块重金属砷、锑污染土壤工程实例,通过对项目概况、施工流程、修复药剂、固化稳定化处理、修复效果评估、修复达标土资源化利用等内容的介绍,总结相关修复参数,积累典型工程经验,以期为其他原址异位固化稳定化类似工程提供指导和支撑。     

两种粘土矿物对重金属污染底泥的稳定性研究

分别向自然条件重金属污染底泥和人工污染重金属污染底泥中添加2种稳定化剂,进行熟化试验和浸出毒性试验,研究膨润土和硅藻土对高、低浓度重金属污染底泥的稳定化效果。结果表明,在一个试验周期内,膨润土和硅藻土对自然条件重金属污染底泥中重金属Cu、Pb、Cr均具有稳定化效果,且对Pb和Cr的抑制能力相似;膨润土和硅藻土对人工污染重金属污染底泥中重金属Cu和Pb的释放具有明显抑制效果,而硅藻土对Cr的释放具有一定抑制作用。     

重金属污染土壤修复的二次污染与防治

美国污染场地修复经验表明,78%的污染场地存在重金属污染。针对重金属污染场地,常用的修复技术有固化/稳定化、淋洗、水泥窑协同处置、植物修复等。我国固化/稳定化技术应用,占所有修复技术33%。重金属污染场地修复需全面考虑二次污染问题。通过分析这4种修复技术的主要环节,重点讨论了修复过程中共通的土壤挖掘、堆放等环节,针对可能存在的水、大气、噪声、固废4个方面的二次污染问题,提出了相应的污染防治措施,以期能够为重金属污染场地修复设计、施工、监理等提供参考。     

重金属污染土壤修复的二次污染与防治

美国污染场地修复经验表明,78%的污染场地存在重金属污染。针对重金属污染场地,常用的修复技术有固化/稳定化、淋洗、水泥窑协同处置、植物修复等。我国固化/稳定化技术应用,占所有修复技术33%。重金属污染场地修复需全面考虑二次污染问题。通过分析这4种修复技术的主要环节,重点讨论了修复过程中共通的土壤挖掘、堆放等环节,针对可能存在的水、大气、噪声、固废4个方面的二次污染问题,提出了相应的污染防治措施,以期能够为重金属污染场地修复设计、施工、监理等提供参考。     

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。