人工湿地基质吸附磷素性能及动力学研究

以铁粉和湿地常用基质(河沙)为研究对象,研究两者对污水中磷素的等温吸附特征,并运用1级和准2级动力学模型分析其吸附磷素的动力学过程,考察其吸附磷素的规律和性能.结果表明,铁粉和河沙对溶液中磷素的等温吸附特征符合非线性Langmuir方程,吸附反应在常温下能自发进行,铁粉吸附磷素反应自发程度、对磷素的吸附能力以及生成物的稳定性都大大超过河沙.结合1级和准2级动力学模型标准偏差R2值、1级动力学模型参数w与Langmuir方程理论最大吸附量Q0的相对误差以及准2级动力学模型参数Qe与Q0的相对误差,铁粉对水溶液中磷素的吸附动力学过程更符合1级动力学模型,河沙对水溶液中磷素的吸附动力学过程更符合2级动力学模型.     

CTMAB-磷石膏对Cr(Ⅵ)的吸附动力学研究

在微波环境下,制备了十六烷基三甲基溴化铵(CTMAB)修饰的CTMAB-磷石膏,并对其结构进行了表征。通过静态吸附实验,研究了CTMAB-磷石膏对Cr(Ⅵ)的吸附特性,探讨了吸附机理,结果表明:CTMAB-磷石膏对Cr(Ⅵ)的吸附符合Langmuir和Freundlich吸附等温模型,但Langmuir吸附等温模型能更好地描述吸附等温曲线。Lagergren准一级吸附动力学方程、Lagergren准二级吸附动力学方程、Elovich吸附方程以及粒子内扩散模型均可较好地描述吸附初始阶段,而整个吸附过程更好地符合Lagergren准二级吸附动力学方程,CTMAB-磷石膏对Cr(Ⅵ)的平衡吸附量为16.3225mg/g,吸附过程由物理吸附、化学吸附及络合沉淀作用共同控制。     

柠檬酸改性柚子皮纤维素对废水中铜离子的吸附

采用静态平衡吸附法用柠檬酸纤维素(Cell-CA)吸附废水中Cu2+,考察了溶液的初始浓度、吸附剂颗粒大小、pH值、吸附时间和温度对吸附的影响,分析了吸附过程的热力学、动力学和等温吸附规律.结果表明,在pH值为5.5时Cell-CA对废水中Cu2+的吸附率为92.7%,吸附容量高达18.54mg/g;对不同温度下的吸附等温线采用Freundlich和Langmuir方程进行拟合,结果显示Langmuir方程的拟合效果更好.模拟吸附动力学实验数据符合准一级和准二级动力学模型,Cell-CA对Cu2+的吸附是放热反应.     

改性活性炭吸附污水中氨氮的性能

采用浸渍法制备一系列过渡金属(Zn,Fe,Cu)改性活性炭吸附剂,并探讨其吸附污水中氨氮的性能。结果表明,过渡金属的添加能在一定程度上提高活性炭吸附氨氮性能,其中铜为最佳改性元素。分别采用准一级动力学方程、准二级动力学方程和颗粒内扩散方程对改性活性炭吸附氨氮行为进行拟合。结果显示改活性炭对氨氮的吸附过程可用Langmuir吸附等温方程较好地拟合,在温度为25℃时,单分子层饱和吸附量为7.19 mg/g,其吸附动力学较符合准二级反应动力学方程。     

改性活性炭吸附污水中氨氮的性能

采用浸渍法制备一系列过渡金属(Zn,Fe,Cu)改性活性炭吸附剂,并探讨其吸附污水中氨氮的性能。结果表明,过渡金属的添加能在一定程度上提高活性炭吸附氨氮性能,其中铜为最佳改性元素。分别采用准一级动力学方程、准二级动力学方程和颗粒内扩散方程对改性活性炭吸附氨氮行为进行拟合。结果显示改活性炭对氨氮的吸附过程可用Langmuir吸附等温方程较好地拟合,在温度为25℃时,单分子层饱和吸附量为7.19 mg/g,其吸附动力学较符合准二级反应动力学方程。     

玉米秸秆活性炭的制备及其吸附含氮废水性能探析

采用玉米秸秆作为制备原料,KHCO₃为活化剂、HCl作为改性试剂制备改性玉米秸秆活性炭,吸附含氮废水,进行物理表征以及吸附动力学性能分析。本实验采取Freundlich与Langmuir模型对等温吸附曲线进行线性拟合,实验数据结果表明,玉米秸秆活性炭对氮素的吸附更加符合Freunglich方程,拟合相关性较好,R²=0.998。随后采用Lagergren准一级及准二级动力学速率模型对活性炭吸附氮素溶液动力学拟合,实验结果表明,Lagergren准二级速率模型可以最准确地描述吸附过程,其中R²=0.95。玉米秸秆活性炭对氨氮的最大吸附量常数达到407.51 mg·g^-1,表明吸附能力较强。     

活性炭纤维电吸附处理含盐溶液吸附特性研究

以活性炭纤维为电极材料处理NaCl模拟水,研究了电吸附过程中电极电压、流量、含盐量等对脱盐效果的影响,同时分析了电吸附对水溶液中离子的吸附动力学特性,并以吸附等温线探讨双电层对水溶液中离子的吸附能力。结果表明,对于特定的电吸附装置,当电源施加电压为2.2 V,304不锈钢板的极板电压为1.77 V,流量为15mL/min时,电吸附的平均脱盐率为41.16%。电吸附过程符合Langmuir单分子层吸附等温模型,施加电压为2.2 V时,Langmuir吸附常数为0.088,饱和吸附容量为5.84 mg/g。准一级反应动力学模型、Elovich方程、二级反应动力学模型拟合程度均不高。相比较,Elovich方程拟合效果较好。     

改性硅藻土对氨氮的吸附行为

用过渡金属(Fe、Cu、Zn)改性硅藻土,利用红外吸收光谱(IR)表征了改性前后硅藻土的结构,并研究了其对氨氮的吸附行为。结果表明,Fe的添加能在一定程度上提高硅藻土吸附氨氮性能。此外,分别采用准一级动力学方程、准二级动力学方程和颗粒内扩散方程对改性硅藻土吸附氨氮行为进行拟合。结果显示,改性硅藻土对氨氮的吸附过程可用Langmuir吸附等温方程较好地拟合,在温度为25℃时,单分子层饱和吸附量为8.11 mg/g,其吸附动力学较符合准二级反应动力学方程。     

改性硅藻土对氨氮的吸附行为

用过渡金属(Fe、Cu、Zn)改性硅藻土,利用红外吸收光谱(IR)表征了改性前后硅藻土的结构,并研究了其对氨氮的吸附行为。结果表明,Fe的添加能在一定程度上提高硅藻土吸附氨氮性能。此外,分别采用准一级动力学方程、准二级动力学方程和颗粒内扩散方程对改性硅藻土吸附氨氮行为进行拟合。结果显示,改性硅藻土对氨氮的吸附过程可用Langmuir吸附等温方程较好地拟合,在温度为25℃时,单分子层饱和吸附量为8.11 mg/g,其吸附动力学较符合准二级反应动力学方程。     

酸性品红在石墨烯上的吸附平衡和吸附动力学研究

用透射电子显微镜对制备得到的石墨烯进行了表征,探讨了反应时间、吸附剂用量和染料初始浓度等对吸附酸性品红效果的影响,采用Langmuir和Freundlich等温吸附模型对吸附平衡进行拟合,又用准一级动力学方程和准二级动力学方程描述石墨烯对酸性品红的吸附动力学过程。结果表明,在石墨烯对AF的吸附,在前10 min内反应速率很快,约在60min内达到吸附平衡,最适的吸附剂投加量为30 mg。准二级动力学模型和Langmuir等温吸附模型能较好描述石墨烯对AF的吸附过程,最大吸附量为62.112 mg/g,计算结果表明该吸附是一种单分子层吸附为主的化学过程。     

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。