载铝改性沸石除氟的热力学和动力学机理研究

本文依次采用1.0 mol/L的氢氧化钠和10％的硫酸铝改性天然沸石,然后经过焙烧得到载铝改性沸石样品.对天然沸石和改性沸石的吸附性能做了比较,考查了溶液pH值和温度对改性沸石吸附容量的影响,并对吸附过程进行了动力学和热力学研究.结果表明:改性沸石的吸附容量远远大于天然沸石,在溶液pH值为6,温度为室温时改性沸石的吸附容量达到最佳为1.44 mg/g;改性沸石对氟离子的吸附动力学符合准二级动力学方程,吸附热力学过程符合Freundlich模型,不同温度下的吸附热力学的吉布斯自由能以及焓变和熵变均为负值表明该吸附过程为自发放热反应;初步探讨了载铝改性沸石对氟离子吸附过程的反应机理.     

吸附分离氯化钙中镁铅离子的试验研究

以去除纯碱副产物氯化钙中的镁铅离子,制取高纯氯化钙为目的,采用吸附的方法,研究了不同吸附剂对镁铅离子的分离效果,以及吸附时间、温度、pH值等因素对改性斜发沸石吸附效果的影响。试验结果表明:改性斜发沸石对氯化钙中镁铅离子有较好的吸附去除效果,吸附时间100min、温度30℃、100ml质量分数为0.5%的氯化钙溶液加吸附剂1.5g、pH10为最优吸附条件。     

粉煤灰合成沸石去除废水中铜离子的研究

粉煤灰通过碱熔融预处理,采用水热法(HT)和微波辅助水热法(MW)均合成了单一的NaPl型沸石,研究了溶液pH值和吸附时间对两种沸石产品去除废水中铜离子效果的影响,探讨了沸石产品去除铜离子的吸附机理.研究表明,合成的两种沸石产品对铜离子具有较强的脱除能力,pH值为6,沸石用量10 g/L,吸附30 min时,铜离子去除率均可达95%以上.铜离子的吸附过程符合Langmiur吸附等温方程式,两种沸石产品的静态饱和吸附量分别为70.08 mg/g和53.30 mg/g.     

改性花生壳对活性黄的吸附性能研究

以甲醛和硫酸改性处理后的花生壳作为生物质吸附剂,对活性黄染料溶液吸附脱色性能进行了研究。考察了溶液的pH值、溶液的初始浓度、温度、吸附剂的用量及大小、吸附时间及溶液中的盐离子浓度等对吸附效果的影响,并对吸附动力学和热力学进行研究。结果表明,改性的花生壳吸附活性黄的最佳条件为:在染料浓度100mg/L、吸附剂的用量10 g/L、pH值为2.0、吸附时间在240 min的条件下,改性花生壳对活性黄的吸附率可达到99%以上;Langmuir型吸附模型能较好地描述改性花生壳对活性黄的吸附实验数据,该吸附过程符合准二动力学吸附模型,且吸附过程的Gibbs自由函数ΔG0,反应活化能Ea=20.60 kJ/mol,吸附反应可以自发进行。     

改性火山石对氟离子的吸附性能研究

选用盐酸改性天然火山石作为吸附剂,研究了其对水中氟离子的去除性能,探究吸附时间、改性火山石投加量和溶液pH值对氟离子吸附效果的影响。结果表明,盐酸改性提高了火山石对氟离子的吸附能力。改性火山石对含氟废水的处理时间较短,120min即可达到平衡;吸附剂投加量为8g·L-1时,氟离子的吸附去除率达到最大,为82.4%;溶液pH为4～7的范围内,对氟离子的吸附去除率达到75%以上。正交实验结果发现,当吸附时间为60min,改性火山石投加量为8g·L-1,溶液pH为4时,对氟离子的吸附效果较好。改性火山石吸附氟离子的过程更符合Langmuir模型,吸附过程更接近单层吸附,吸附容量可达0.91mg·g-1,吸附动力学符合Lagergren二级动力学方程,吸附速率快。     

电解锰渣基沸石对锰离子的吸附性能研究

电解锰渣是电解锰行业露天堆存的大宗固体废弃物,在堆存过程中将产生毒性污染物锰离子。为有效利用电解锰渣的同时消除锰离子对环境的危害,以电解锰渣为原料采用微波碱熔活化法制备沸石,并用于吸附锰离子。考察了溶液初始锰离子质量浓度、溶液pH、吸附温度和吸附时间等因素对锰离子吸附效果的影响。结果表明:在溶液初始锰离子质量浓度为500 mg/L、溶液pH为6、吸附时间为2 h、吸附温度为50 ℃条件下,电解锰渣基沸石对锰离子具有较好的吸附能力,最大吸附量高达79.18 mg/g。探究了电解锰渣基沸石对锰离子的吸附行为。结果表明,锰离子在沸石表面的吸附符合准二级动力学模型,Langmuir等温吸附模型比Freundlich模型更适合于描述电解锰渣基沸石去除锰离子的等温吸附过程。电解锰渣基沸石循环使用性能良好,在重金属废水处理方面具有潜在的应用前景。     

纳米TiO_2对氟离子吸附性能研究

采用低温水解法制备纳米TiO2,研究了纳米TiO2吸附剂对氟离子的吸附行为,考察了硫酸钛浓度、纳米TiO2投加量、pH值和接触时间对吸附氟离子的影响。结果表明,硫酸钛浓度为0.20 mol/L时得到的纳米TiO2对氟离子吸附效果最好;纳米TiO2的吸附量随溶液pH值的升高而下降,当pH值为4.0时最大吸附量为28.8 mg/g;100 min内纳米TiO2对氟离子的吸附率可以达到78.5%;吸附动力学研究表明,纳米TiO2对氟离子的吸附动力学可以用准二级动力学方程来描述,吸附过程符合Langmuir等温吸附模型。     

载镧活性氧化铝的除氟及再生性能研究

为研究载镧活性氧化铝对F-的吸附能力,文中实验利用浸渍法合成载镧活性氧化铝,分别探究吸附时间、pH值、吸附剂用量、干扰离子对吸附过程的影响,同时利用不同浓度的NaOH溶液对吸附剂进行再生,探究吸附剂的再生效果.结果表明:对于质量浓度为10 mg/L的F-溶液,吸附剂用量为5 g/L,其除氟效率为86％,酸性条件下有利于...     

氢氧化镁改性硅藻土对水中活性红的吸附性能研究

对氢氧化镁改性硅藻土吸附去除活性红染料的行为进行了研究,探讨了pH值、吸附剂用量、NaCl浓度等因素对吸附脱色率的影响.结果显示当改性硅藻土投加量为6 g/L,溶液pH值为6,NaCl浓度为4 mol/L,该吸附剂对活性红溶液的脱色率可达95％.实验结果也表明氢氧化镁改性硅藻土对活性红的吸附符合Langmuir等温模型和准二级动力学模型,最大吸附量为64.94 mg/g.热力学研究表明氢氧化镁改性硅藻土对活性红的吸附是一自发、放热过程.     

天然沸石负载壳聚糖吸附废水中铅离子的研究

根据天然沸石离子交换特性和壳聚糖在溶液中带有的正电荷,将80目天然沸石与65%脱乙酰度壳聚糖的0.5%醋酸溶液混合,使壳聚糖负载在天然沸石上,制成颗粒吸附剂,用于去除废水中Pb2+.最佳工艺条件是壳聚糖与天然沸石质量比为120,颗粒吸附剂用量为15g/L,废水中Pb2+质量浓度不大于100mg/L,pH为4～4.5,吸附平衡时间为8 h,Pb2+去除率为99%.与活性炭吸附法相比,天然沸石-壳聚糖复合吸附剂吸附效果相近,成本仅为其1/6.与单一的天然沸石或壳聚糖相比,该吸附剂对Pb2+离子的吸附能力强,成本低.     

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.     

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.     

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.     

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.     

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.