托贝莫来石改性及其对亚甲基蓝的吸附性能EI北大核心CSCD

对托贝莫来石(TOB)进行加热与酸化复合改性,成功制备出比表面积为570 m^(2)/g的酸化改性托贝莫来石(AHTOB),并用X射线衍射、N2吸附-脱附对改性托贝莫来石进行了结构表征和表面积及孔径分析。通过静态吸附实验探讨了3种吸附剂对亚甲基蓝溶液(MB)的吸附性能,分析改性TOB对MB的吸附机制。考察了不同吸附剂及其加入量、溶液p H值、MB初始浓度、吸附时间及温度对吸附行为的影响,研究了AHTOB对MB溶液吸附的热力学和动力学行为。结果表明:对50 m L,浓度为10 mg/L的MB进行吸附,未改性TOB、热改性HTOB以及酸化改性AHTOB对MB的吸附率分别达到50、53.72%和97.35%。对于不同初始浓度的MB,TOB和HTOB的最大吸附量可达102.36 mg/g和113.80 mg/g,AHTOB的吸附量达到248.01 mg/g,经过加热与酸化复合改性的AHTOB对MB的吸附效率有了明显的提升,得到了吸附MB溶液的最佳外界条件:p H值为5~7,震荡时间为30 min,温度为20~25℃。     

醚化改性聚乙烯醇的合成研究

以10%NaOH为催化剂,环氧氯丙烷(EPIC)为醚化剂,对聚乙烯醇(PVA)进行了醚化改性,并用FT-IR对醚化改性产物的结构进行了表征,考察了工艺条件对PVA醚化改性产物醚化程度的影响。实验结果表明,当n(PVA):n(EPIC)为1.0∶1.5、反应温度为65℃、反应时间为6 h时,醚化程度达到49.1%。     

活性炭的改性条件及其对硫化氢吸附性能的影响

以工业活性炭为载体制备改性活性炭,对比研究了未改性活性炭,NaOH、Na2CO3、Fe(NO3)3、Cu(Ac)2改性活性炭及挂膜硫氧化细菌后活性炭在相同条件下对硫化氢穿透时间及吸附容量的影响。结果表明：在相同控制条件下,NaOH改性活性炭明显优于其它改性剂;不同梯度改性剂条件下,20% NaOH改性活性炭对硫化氢的吸附效果最好,吸附穿透容量为78.25 mg/g,穿透时间可以达到2000 min以上;不同改性剂挂膜硫氧化细菌后对硫化氢均有一定的处理效果,其中对已达到饱和吸附的NaOH改性活性炭挂膜后的再生效果可以达到100%以上,说明挂膜硫氧化细菌活性炭对硫化氢的处理具有很好的效果。     

橘子皮的皂化改性及其吸附铜离子的影响因素

以NaOH皂化改性的橘子皮为吸附剂,并以橘皮粉投加量(Q)、pH值、搅拌速度(n)、温度(T)、吸附时间(t)为考察因素,对自制模拟实验室含铜废液进行了吸附实验。通过原子吸收分光光度法(Atomic Absorption Spectrometry,AAS)测定了吸附前后水中Cu~(2+)的浓度,并探讨了在不同试验条件下,橘皮粉对铜离子的吸附率。最适宜吸附条件为:Q 25.00 g/L、pH值4.00、r 120 r/min、T室温(15~35℃)、t 60 min。     

托贝莫来石改性及其对亚甲基蓝的吸附性能

对托贝莫来石(TOB)进行加热与酸化复合改性,成功制备出比表面积为570 m2/g的酸化改性托贝莫来石(AHTOB),并用X射线衍射、N2吸附-脱附对改性托贝莫来石进行了结构表征和表面积及孔径分析.通过静态吸附实验探讨了3种吸附剂对亚甲基蓝溶液(MB)的吸附性能,分析改性TOB对MB的吸附机制.考察了不同吸附剂及其加入...     

改性炭对H2S吸附性能的研究

以工业4#活性炭为载体,制备磺化酞菁钴(CoPcS)改性活性炭,对比研究了NaOH、Cu(AC)2、CoPcS改性活性炭在相同条件下净化H2S的吸附性能为:CoPcS>Cu(AC)2>NaOH;考察了反应条件对净化电石炉尾气中的H2S气体的影响;并对空白活性炭、改性活性炭吸附前后作SEM表征分析。结果表明,反应温度60℃、氧含量1.5%为改性活性炭的最佳反应条件。结合SEM表征分析表明:改性活性炭孔结构的变化和表面活性物质的生成使其对H2S的吸附净化效果增强。     

蜡质玉米羧甲基淀粉的合成与表征

以蜡质玉米淀粉为原料,用乙醇溶剂法制备了蜡质玉米羧甲基淀粉(CMS)。考察了碱化时间、醚化反应温度、醚化反应时间、n(NaOH)/n(淀粉)、n(ClCH2COONa)/n(淀粉)对CMS粘度的影响。结果表明,在醚化反应时间2.5 h,n(NaOH)/n(淀粉)为0.4,n(ClCH2COONa)/n(淀粉)为1.2,醚化反应温度65℃,碱化时间为50 min的最佳反应条件下制得的CMS粘度为1 490 mPa.s。同时发现,随着n(ClCH2COONa)/n(淀粉)的增大,CMS粘度表现出先增大后减小再增大,最后减小的趋势,对其进行了分析。     

低浓度氰化氢在浸渍活性炭上的吸附净化研究

采用浸渍法改性活性炭吸附脱除低浓度氰化氢(HCN),研究了NaOH与磺化酞菁钴(CoPcS)混合浸渍改性活性炭净化HCN的性能。研究表明:改性炭在制备过程中适当增加NaOH的浓度有利于提高其吸附HCN的能力,当NaOH浸渍液浓度为10%时,CoPcS/NaOH配比0.15mg·g-1、焙烧温度350℃为最佳制备条件;吸附反应阶段较适宜的体积空速为923h-1、氧体积分数2%、吸附温度为90℃。N2吸附表征了活性炭的比表面积和孔结构性质,与原活性炭相比,CoPcS与NaOH混合浸渍改性活性炭的比表面积和孔体积有所降低,但对HCN的吸附能力却显著提高,说明HCN与浸渍剂在活性炭表面发生了化学反应;孔径分布说明HCN在改性炭的中孔或大孔上参与化学吸附造成微孔扩充,而不是微孔填充和覆盖。     

碱木质素对亚甲基蓝的吸附行为及作用机制

为建立提高碱木质素(KL)吸附性能的改性理论依据,并推进其作为染料废水吸附材料的工程化应用,研究了 KL对染料废水中亚甲基蓝(MB)的吸附性能和吸附作用机制.考察了 MB初始质量浓度、吸附时间和溶液pH值对KL吸附MB的影响规律.结合溶液环境对吸附行为的影响规律以及红外光谱,研究了 KL和MB间的相互作用机制.实验表明...     

粉煤灰基成型吸附剂的制备及其对亚甲基蓝的吸附性能

为了增加粉煤灰的反应活性,将原料粉煤灰(raw fly ash,RFA)进行超细球磨得到超细粉煤灰(ultra-fine fly ash,UFA),将超细粉煤灰与NaOH溶液反应后挤出成型烘干,得到超细粉煤灰基成型吸附剂(ulWa-finc forming fly ash.based adsorbent,UFFA),通过X射线衍射和扫描电子显微镜对其进行表征.研究了RFA,UFA和UFFA对亚甲基蓝(methylene blue,MB)的吸附性能.结果表明:UFFA的吸附性能最好,其次为UFA,RFA最差.UFFA对MB的吸附过程符合二级吸附动力学模型,UFFA对MB的吸附过程由颗粒内扩散过程控制.热力学研究表明:UFFA对MB的吸附符合Fromdlich吸附等温式;UFFA对MB吸附热力学参数△G小于0,表明吸附过程是白发进行的;△H为-13.84kJ/mol,表明吸附是放热过程.     

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.     

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.