无机调理剂与表面活性剂联合调理对污泥脱水性能的影响

研究了CaO,PAFC联合表面活性剂预处理对污泥脱水性能的影响。以污泥滤饼含水率和比阻(SRF)作为评价污泥脱水性能的指标,通过测定污泥调理过程中胞外聚合物(EPS)含量、Zeta电位的变化来阐明污泥脱水性能的变化。实验结果表明,十二烷基二甲基苄基氯化铵(1227)的加入导致上清液中EPS含量发生变化,有效降低了SRF和滤饼含水率,提高污泥脱水性能。CaO,PAFC和表面活性剂的联合调理污泥比单独使用表面活性剂的效果更好,CaO,PAFC的投加不仅改善污泥脱水性能,并有助于减少表面活性剂的用量。污泥上清液中EPS及其各组分含量与污泥滤饼含水率、SRF均有较高的相关性,对污泥的脱水性能有重要贡献。实验中确定的最佳污泥调理条件是CaO投加量为66.67 mg·(g DS)-1,PAFC投加量为33.33 mg·(g DS)-1和表面活性剂投加量为56.25 mg·(g DS)-1,污泥滤饼含水率和SRF分别降至69.41%和2.94×1012m·kg-1。     

无机调理剂与表面活性剂联合调理对污泥脱水性能的影响

研究了CaO、PAFC联合表面活性剂预处理对污泥脱水性能的影响。以污泥滤饼含水率和比阻(SRF)作为评价污泥脱水性能的指标,通过测定污泥调理过程中胞外聚合物(EPS)含量、Zeta电位的变化来阐明污泥脱水性能的变化。实验结果表明,十二烷基二甲基苄基氯化铵(1227)的加入导致上清液中EPS含量发生变化,有效降低了SRF和滤饼含水率,提高污泥脱水性能。CaO、PAFC和表面活性剂的联合调理污泥比单独使用表面活性剂的效果更好,CaO、PAFC的投加不仅改善污泥脱水性能,并有助于减少表面活性剂的用量。污泥上清液中EPS及其各组分含量与污泥滤饼含水率、SRF均有较高的相关性,对污泥的脱水性能有重要贡献。实验中确定的最佳污泥调理条件是CaO投加量为66.67 mg·(g DS)?1、PAFC投加量为33.33 mg·(g DS)?1和表面活性剂投加量为56.25 mg·(g DS)?1,污泥滤饼含水率和SRF分别降至69.41%、0.294×1013 m·kg?1。     

PAC投加对膜生物反应器的污泥特征和膜污染的影响

考察了投加粉末活性炭( PAC)对长期运行的膜生物反应器(MBR)中污泥混合液特性和膜污染的影响,并分析了其对膜污染的影响机理.结果表明,PAC的投加使污泥絮体平均粒径增加、污泥的粘度减小,而对污泥含量影响不大.投加PAC可降低混合液中溶解性EPS含量,质量浓度从MBR反应器混合液中的平均87.17 mg·L-1降至PAC-MBR反应器内65.54 mg·L-1;同时PAC对膜表面的EPS也有吸附作用,能将沉积在膜表面的EPS吸附到其表面,使得膜表面的EPS质量浓度从MBR反应器内的970.6 mg·L-1降至PAC-MBR反应器内的699.0 mg· L-1,同时改变了膜表面的EPS组成,使得蛋白质、多糖的质量比降低,减缓了膜的有机污染,延长了膜组件的清洗周期.     

无机调理剂与表面活性剂联合调理对污泥脱水性能的影响

研究了CaO、PAFC联合表面活性剂预处理对污泥脱水性能的影响。以污泥滤饼含水率和比阻（SRF）作为评价污泥脱水性能的指标,通过测定污泥调理过程中胞外聚合物（EPS）含量、Zeta电位的变化来阐明污泥脱水性能的变化。实验结果表明,十二烷基二甲基苄基氯化铵（1227）的加入导致上清液中EPS含量发生变化,有效降低了SRF和滤饼含水率,提高污泥脱水性能。CaO、PAFC和表面活性剂的联合调理污泥比单独使用表面活性剂的效果更好,CaO、PAFC的投加不仅改善污泥脱水性能,并有助于减少表面活性剂的用量。污泥上清液中EPS及其各组分含量与污泥滤饼含水率、SRF均有较高的相关性,对污泥的脱水性能有重要贡献。实验中确定的最佳污泥调理条件是CaO投加量为66.67 mg·（g DS）^-1、PAFC投加量为33.33 mg·（g DS）^-1和表面活性剂投加量为56.25 mg·（g DS）^-1,污泥滤饼含水率和SRF分别降至69.41%、0.294×10¹³ m·kg^-1。     

Fenton试剂对剩余污泥脱水性能的改善

研究了利用Fenton试剂调理城市污水处理厂剩余污泥,通过测定污泥毛细吸水时间(CST)、污泥比阻(SRF)和泥饼含水率来表征污泥脱水性能的变化,分别考察了污泥初始pH、H2O2投加量、H2O2/Fe2+、反应温度和反应时间对污泥调理效果的影响。综合考虑,确定Fenton调理污泥的最佳条件为:pH=3、抽滤脱水和离心脱水H2O2最佳投加量分别为3 g/L和9 g/L、H2O2/Fe2(+质量比)最佳范围为8～12、反应温度50℃、反应时间60 min。对污泥离心上清液中胞外聚合物(EPS)含量的研究表明,Fenton调理后污泥上清液中蛋白质和多糖含量有大幅升高,说明Fenton试剂能有效氧化破解EPS,从而提高污泥的絮凝性,改善污泥的脱水性能。Fenton氧化后污泥颗粒粒径变小,比表面积增大。     

PAC-DMBR复合工艺的运行特性及处理效果研究

采用3组动态膜生物反应器(DMBR)分别投加不同量的粉末活性炭(PAC)同时运行平行实验的方法,考察投加PAC对长期运行的PAC-DMBR复合工艺处理生活污水的效果及对污泥混合液特性的影响。结果表明,投加PAC后强化了PAC-DMBR对污染物的处理效果,COD、氨氮、TP、UV_(254)和色度的去除率均有提升。PAC投加量为3g/L时运行效果最好,稳定通量增加且运行周期延长,浊度在30 min内即降至1 NTU以内,且出水水质更好。投加PAC后改善了污泥混合液特性,促进了动态膜的形成过程及结构改变,主要表现为投加PAC后污泥粒径均有增大,污泥混合液沉降性能更好,EPS含量降低且比好氧速率有轻微提升。     

硝酸钙投加量对污泥生物调理效果的影响

在接种了反硝化细菌的剩余污泥中投加Ca(NO_3)_2,利用反硝化细菌的作用降低污泥胞外聚合物的含量,调理改善污泥脱水性能。在以硝酸根浓度分别为50、100、150、200 mg/(g TS)的不同投加量下对污泥进行调理,结果表明,当投加量为100 mg/(g TS)时,污泥的脱水性能最佳。其中CST较对照组降低了43.6%,SRF降低了55.9%,Zeta电位更趋于电中性,泥饼含水率有明显下降。同时,污泥S-EPS和LB-EPS中蛋白质含量有显著的降低,分别从13.87 mg/L和12.47 mg/L降低到2.37 mg/L和2.65 mg/L,从而脱水性能得到了明显的改善。     

聚合氯化铝投加时间对好氧颗粒污泥的形成和胞外聚合物的影响

通过在好氧颗粒污泥培养过程中分别在第1～7天和第8～14天投加聚合氯化铝(PAC)的方式,分析颗粒的形成过程,并研究胞外聚合物总量及其各组分的含量变化和空间分布。研究发现:第8～14天投加PAC的反应器形成颗粒时间提前了6天,且形成的颗粒外形规则,大小均匀,去除污染物性能良好;反应器中胞外多聚物和蛋白质含量总体较多,且随颗粒的形成而增加,之后略有下降并在颗粒成熟后维持稳定,蛋白质/多糖的值在颗粒形成期均增加超过2.5倍,有利于颗粒污泥的形成;多重荧光染色表明:两个反应器中PAC投加时间不同,β-D-呋喃葡萄糖、脂类和活细胞均呈现不同的分布情况,但对蛋白质和α-呋喃葡萄糖、α-甘露糖分布的影响较小。     

处理炼油废水时粉末活性炭对MBR的影响机理

通过平行实验,考察了粉末活性炭(PAC)投加对MBR处理实际炼油废水时混合液性质的影响,拟合了膜阻力与混合液中胞外聚合物(EPS)、溶解性有机物(SMP)含量以及混合液黏度的关系,并进一步探讨了PAC影响MBR混合液性质的机理。结果表明,PAC的加入有效降低了膜污染速率,延长了单个周期内MBR的运行时间;炼油废水MBR系统中的混合液特性(EPS含量、SMP含量和混合液黏度)与膜阻力都呈现较强的指数相关关系;PAC的投加,降低了炼油废水MBR系统运行过程中混合液内EPS和SMP的含量及混合液黏度,从而改变了混合液特性,使得膜污染减缓并延长膜运行的时间;PAC的投加降低了混合液中EPS的含量,这是处理炼油废水时PAC影响MBR膜污染的根本机理,混合液EPS含量的降低,使SMP含量和混合液黏度均降低,从而抑制了膜污染。     

PAM与PAC复配调理对污泥脱水及流变的影响

探究有机调理剂(PAM)与无机调理剂(PAC)联用对北京市某污水处理厂热水解厌氧消化污泥脱水及流变的影响。结果表明,单独投加PAM或PAC均可以提高抽滤泥饼含固率,PAM效果要优于PAC。当复配投加PAC掺量4%,PAM掺量2.5‰时,滤饼的含固率最高,达到35.15%。经PAC+PAM联合调理的污泥,相比原泥和单一调理剂的污泥,有着更少的S-EPS和LB-EPS,表明污泥脱水能力有显著提升。添加复配调理剂的污泥中蛋白含量最少,结合水得到释放,有利于水分去除。此外,PAM的投加能降低污泥的屈服应力,而PAC则会增大调理污泥的屈服应力,PAM、PAC能增大污泥稠度,降低流动行为指数(n)。复配调理污泥表现出与PAM单独调理污泥相似的流变参数变化规律。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

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.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。