Fenton试剂处理含乌洛托品废水的研究

采用Fenton试剂氧化处理含乌洛托品废水,探讨了Fenton试剂氧化乌洛托品废水的影响因素与反应条件。实验表明,当H2O2投加量为126 mmol/L,FeSO4.7H2O投加量为42 mmol/L,氧化反应时间2 h,废水的pH=3的实验条件下,模拟废水CODCr去除率接近70%,有效降低了后续生化处理的负荷。     

Fenton试剂氧化处理TNT废水的试验研究

TNT废水毒性大,不适宜用常规方法进行处理。研究了Fenton试剂对实际TNT废水的处理效果,确定了最佳条件:H2O(230%)=3.33ml/L,FeSO(4浓度为0.5mol/L)=1.67ml/L,pH为3.00,反应时间2h,温度40℃。此条件下废水CODCr和TNT去除率可达93%以上。     

Fenton高级氧化-铁碳微电解处理难降解有机废水的研究

采用Fenton高级氧化和铁碳微电解技术处理含硝基苯的模拟染料废水,通过重铬酸钾法测定化学需氧量(CODCr),确定最佳工艺参数。实验结果表明,在室温条件下,模拟废水CODCr为1825 mg/L,Fenton高级氧化处理废水的最佳条件为FeSO4和H2O2加入量分别为180 mg/L和4.8 mL/L,反应时间60 min,CODCr去除率可达79.07%;铁碳微电解处理废水的最佳条件为铁屑大小是40目,铁碳加入量为20 g/L,铁碳质量(g)比为1.5∶1,处理60 min,CODCr去除率可达50.50%;Fenton高级氧化-铁碳微电解联合处理时,CODCr去除率高达97.80%。     

Fenton试剂预处理农药废水实验

对Fenton氧化法预处理农药废水进行了研究,通过考察H2O2投加量、[Fe2 ]/[H2O2](摩尔比)、pH值、反应时间、Fenton试剂投加方式等因素对该农药废水化学需氧量(CODcr)、色度去除率的影响,确定了反应的最佳条件:即H2O2的投加量为50 mmol/L,[Fe2 ]/[H2O2]为1:10,pH值为3,反应时间为2h,Fenton试剂分4次投加.在此条件下CODcr去除率可达68.07%、色度去除率可达90.11%;Fenton氧化预处理后废水的可生化性也得到了大大提高.     

Fenton氧化技术处理含甲醛废水的实验研究

采用Fenton试剂对甲醛废水进行氧化处理,考察了H2O2浓度、Fe2＋浓度、pH值、反应时间等因素对处理效果的影响。在H202投加量为4．5ml／L,n（H202）：n（Fe2＋）=4,pH值为3,反应30rain后,静置5min的条件下,废水中甲醛去除率和COD去除率分别达到89％、82％。结果表明,Fenton试剂对甲醛废水可以取到很好的处理效果。     

混凝与Fenton预处理医药中间体废水研究

分别采用混凝和Fenton对医药中间体废水进行预处理,探究了混凝剂的种类,Fenton反应的p H、反应过程中H2O2和Fe2+的摩尔比等因素对医药中间体废水预处理的影响,在适宜参数条件下比较了3种联合预处理方法对COD的去除效率。结果表明,最适混凝剂为聚合氯化铝铁(PAFC),其COD去除率为14.34%;Fenton氧化的适宜反应条件为:初始p H=3.5,n(H2O2)/n(Fe2+)为4。适宜条件下经过2 h的Fenton反应,COD去除量为5.675 g/L,去除率达26.03%。三者联合预处理效果顺序为2级Fenton混凝+FentonFenton+混凝,其中混凝+Fenton去除率为33.49%,二级Fenton为41.74%。     

超声-Fenton法协同处理生化后制药废水研究

研究在酸性环境下,超声协同Fenton技术对废水有机物的去除,同时考察p H、H2O2浓度、Fe2+浓度、超声功率和反应时间等因素对降解生化后发酵制药废水的影响。结果表明:Fenton试剂辅以超声作用后,CODCr去除效果优于单独超声、单独Fenton法;同时确定了超声-Fenton氧化法降解生化后发酵制药废水最佳工艺参数:在超声波功率为75 W、溶液p H为4.0、H2O2浓度为4.70 mmol/L,Fe2+浓度为6.50 mmol/L,反应时间为30 min条件下,CODCr最高去除率可达到71.5%,色度去除率可达到97%。     

水热辅助Fenton试剂氧化法深度处理显影废水的研究

研究了水热辅助Fenton试剂氧化法对中和沉淀-气浮工艺处理后的显影废水的深度处理效果和影响因素.结果表明,在最佳反应条件下,当进水CODCr为300～400 mg/L时,处理出水CODCr＜60 mg/L,达到《污水综合排放标准》(GB 8978-1996)一级标准要求.在实验条件下,最佳反应参数为:初始pH为2.5,反应温度为110℃,FeSO4·7H2O投加质量浓度为3.6 g/L,30％H2O2投加质量浓度为3.3～3.7 g/L,反应时间为1～2 h.水热辅助Fenton试剂氧化法的CODCr去除率可达85.2％.     

UV/Fenton氧化法对苯酚氧化效果的实验研究

研究UV/Fenton氧化法中各个因素对降解水中苯酚的影响,确定UV/Fenton法处理苯酚废水的工艺条件。保持UV/Fenton体系的基准条件不变,通过改变H2O2浓度、n(Fe2+)∶n(H2O2)、废水初始pH值等实验条件,考察这些因素对UV/Fenton法处理苯酚废水效果的影响。结果表明:UV/Fen-ton氧化法对苯酚废水有较好的去除效果和较高的反应速率。当废水初始pH值为3.0时,经30 min的反应,苯酚去除率达到99%,COD去除率达到86%。但是苯酚废水COD去除率滞后于苯酚去除率。UV/Fenton法能够在较短的时间内去除苯酚和COD,H2O2浓度、n(Fe2+)∶n(H2O2)对处理效果影响较大,H2O2浓度决定苯酚去除率和COD去除率,而n(Fe2+)∶n(H2O2)是影响降解速率的主导因素。     

Fenton试剂处理邻氯苯胺废水的研究

采用Fenton试剂氧化处理含邻氯苯胺的生产废水,研究了H2O2,Fe2+投加量以及反应体系pH值对废水COD去除率的影响。通过实验,确定了Fenton试剂处理该废水的最佳操作条件:在pH值为3,FeSO4.7H2O的投加量为Fe2+在废水中的质量浓度达到0.56 g/L,每升废水中H2O2(质量分数30%)投加量18 mL时,废水的COD去除率达到72.9%。     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.     

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.