稀土改性13X分子筛的表征与脱硫性能评价

采用离子交换法制备了Ce/13X、La/13X及La-Ce/13X分子筛吸附剂。通过X射线衍射、N2物理吸附、扫描电子显微镜、傅里叶红外光谱等手段对吸附剂进行表征,考察对比了三种吸附剂的动态吸附性能以及温度和流速对吸附性能的影响,并对吸附剂进行再生。结果表明,稀土离子改性后的13X分子筛的比表面积、孔体积出现一定程度的下降,分子筛结晶度降低但并未改变其骨架结构。La的载入与Ce具有协同作用,使得双金属改性的La-Ce/13X分子筛在脱硫吸附性能上较单金属改性的分子筛有明显的提高。常温下,空速为6h-1,La-Ce/13X分子筛能够将起始浓度为0.2mg/g的模拟油脱除至0.01mg/g,经过7h后穿透,穿透硫容为6.118mg/g,吸附剂经过氮气气氛300℃焙烧2h后,可较好的再生。     

AgCo13X改性分子筛的制备与吸附脱硫性能

采用液相离子交换法制备了以金属离子Co2+和Ag+共同改性的AgCo13X分子筛吸附剂,并用XRD、NH3-TPD、BET和TG等技术对其结构进行表征。在模拟柴油中考察了吸附剂对二苯并噻吩(DBT)的脱硫性能。结果表明:AgCo13X分子筛的脱硫性能优于单一离子改性的Co13X和Ag13X分子筛;而Co13X和Ag13X分子筛的脱硫性能又明显高于未改性的13X分子筛。当Ag+离子交换浓度为0.1 mol/L时制备的Co2+和Ag+共同改性的AgCo13X分子筛具有最好的脱硫性能,其脱硫率为99.91%。剂油比为0.02 g/mL,当吸附时间为1 h即可达到吸附平衡;吸附剂具有良好的稳定性和再生性,再生后的脱硫率达到98.21%。     

草酸改性NaY分子筛对乙烯吸附研究

以Na Y分子筛为原料,草酸为扩孔剂,制得改性Na Y分子筛作为载体,通过等体积浸渍Ag NO3,焙烧制得π络合吸附剂。并通过XRD、FTIR表征了分子筛结构,BET测定了分子筛比表面积和孔径;通过吸附乙烯,考察了改性Na Y分子筛空白样乙烯吸附量、负载30%Ag NO3乙烯吸附量、75℃真空脱附后乙烯吸附量。结果表明,采用草酸对Na Y分子筛脱铝扩孔后,孔径达到1.4 nm,乙烯吸附曲线变平缓;改性π络合吸附剂比未改性π络合吸附剂更容易脱附,在75℃真空脱附条件后,改性π络合吸附剂吸附量达到首次吸附量95%以上。     

草酸改性NaY分子筛对乙烯吸附研究

以Na Y分子筛为原料,草酸为扩孔剂,制得改性Na Y分子筛作为载体,通过等体积浸渍Ag NO3,焙烧制得π络合吸附剂。并通过XRD、FTIR表征了分子筛结构,BET测定了分子筛比表面积和孔径;通过吸附乙烯,考察了改性Na Y分子筛空白样乙烯吸附量、负载30%Ag NO3乙烯吸附量、75℃真空脱附后乙烯吸附量。结果表明,采用草酸对Na Y分子筛脱铝扩孔后,孔径达到1.4 nm,乙烯吸附曲线变平缓;改性π络合吸附剂比未改性π络合吸附剂更容易脱附,在75℃真空脱附条件后,改性π络合吸附剂吸附量达到首次吸附量95%以上。     

甲酸铜还原制备煤质活性炭CuCl吸附剂工艺研究

以煤质活性炭为载体,氯化铜为铜源,甲酸铜为还原剂,采用热分散法制备CuCl-AC吸附剂。通过变压吸附法(PSA)测量该吸附剂对乙烯乙烷吸附分离性能。考察了铜担载量、焙烧温度、焙烧时间等因素的影响。结果表明,通过甲酸铜还原法制备CuCl-AC吸附剂,最佳制备工艺条件为:CuCl_2担载量为4mmol,Cu(HCOO)_2担载量为4mmol,焙烧温度300℃,焙烧时间4 h。在30℃,0.5MPa的条件下,它对乙烯的吸附量为32.39 mL/g,分离系数为2.47,对变压吸附具有很好的分离应用前景。     

活性氧化铝的改性及除铬（Ⅵ）性能研究

铬离子(Ⅵ)是环境中重要的污染物质之一,因此,解决其污染问题刻不容缓。以活性氧化铝为吸附材料,采用氢氧化钠浸渍法对其进行改性,获得具有良好吸附性能的铬离子(Ⅵ)吸附剂。考察了焙烧时间、焙烧温度、改性剂浓度、固液比和浸渍时间等因素对改性活性氧化铝吸附性能的影响~([1])。结果表明,改性后的活性氧化铝对铬离子(Ⅵ)的吸附性能显著提高~([2])。氢氧化钠改性活性氧化铝的最佳工艺条件为焙烧时间2 h、焙烧温度500℃、氢氧化钠的浓度10 g/L、固液比1 g∶5 mL、改性时间0.5 h。此时,铬离子(Ⅵ)吸附率高达96%。该铬离子(Ⅵ)吸附剂具有一定的应用前景。     

氧化铈改性沸石脱氮的研究

用浸渍焙烧法制备稀土吸附剂,用于静态脱氮实验。结果表明,氧化铈改性的稀土吸附剂吸附性能优于氧化镧和氧化镧-氧化铈复合改性的稀土吸附剂;当吸附剂用量为2 g/L,进水pH为4~6,吸附时间为2.5 h,氧化铈改性稀土吸附剂对模拟废水氨氮浓度为20 mg/L的吸附率达到80.23%;吸附剂再生6次后氨氮的去除率下降不到7%,说明吸附剂具有较好的稳定性。     

煤基活性炭络合吸附剂对乙烯/乙烷吸附分离性能研究

以煤基活性炭为载体,利用等体积浸渍法制备载铜络合吸附剂,并对该吸附剂分离乙烯乙烷的性能进行评价。考察了焙烧温度、Cu Cl2担载量、助剂Ce O2担载量、再生等因素的影响,利用XRD、SEM等手段对吸附剂进行表征。结果表明,改性后的煤基活性炭是分离乙烯/乙烷的优良吸附剂。最佳制备工艺条件:Cu Cl2担载量为6 mmol/g,助剂Ce O2担载量为0.7 mmol/g,焙烧温度为250℃。在70℃、0.6 MPa时,载铜复合吸附剂对乙烯的吸附量高达25.15 m L/g,分离系数为5.20,具有一定的工业应用前景。     

凹凸棒石基吸附剂的制备及改性

探讨了甘肃产凹凸棒石与活性氧化铝复配所制吸附剂的吸附性能,考察了原料配比、焙烧温度对该吸附剂吸附性能的影响,以及吸附剂改性后的吸附性能。根据试验结果,初步确定了吸附剂的原料配方,其中凹凸棒石占总质量的55％-70％,活性氧化铝占总质量的25％～40％。研究发现,在此配比及焙烧温度为600—700℃时．该吸附剂具有高吸附性;采用浓度为1．0mol／L的硫酸改性1．0h可使吸附剂具有较高的吸附容量。     

CuCI负载型吸附剂吸附CO的研究

利用Cu＋能与C0结合形成羰基络合物,将Cu＋盐负载到分子筛表面,经过热处理能达到自发单层分散状态,有效提高了C0的吸附量。利用直接混合法将CuCl负载于13X分子筛表面上制备高效的CO专用吸附剂。实验结果表明,将样品置于管式炉内,流动N2氛围保护下,在350℃焙烧4h后,CuCl／13X质量比0．4：1．0吸附剂表现出较好的吸附性能,C0吸附量可迭45mL／g,对工业分离混合气体有重要的意义。XRD也显示,不同质量比的CuCl／13X样品,在N2氛围中350℃焙烧4h后,CuCl晶相峰从有变无,说明CuCl均匀分散于栽体表面,提供了更多的与C0络合的铜离子活性中心,进而提高了吸附剂对C0的吸附量。     

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.