天然维生素E油中PAH4连续脱除工艺研究北大核心CSCD

建立了一种天然维生素E油连续通过颗粒活性炭的固定床吸附工艺,从而实现有效脱除其中含有的微量多环芳烃(PAHs)。通过单因素实验分别考察了料液比、体系温度、物料在填料中的吸附时间对PAH4(苯并(a)芘、苯并(a)蒽、苯并(b)荧蒽、䓛)脱除效果的影响,并通过正交实验进行了工艺条件优化。同时,考察了PAH4脱除过程对天然维生素E含量的影响。结果表明:以95%乙醇为溶剂,料液比(天然维生素E油与溶剂比)1∶3,体系温度40℃,在以颗粒活性炭为填料的固定床内吸附4 h的条件下,可使天然维生素E油中PAH4的残留量降至7.3μg/kg(其中苯并(a)芘含量为1.8μg/kg),符合欧盟标准要求的苯并(a)芘含量小于或等于2μg/kg,PAH4含量小于或等于10μg/kg的限量标准,且采用该PAH4脱除工艺后维生素E的含量没有受到明显影响。     

Extraction of Mutagens from Chlorinated Poultry Chiller Water

Poultry chiller water (PCW) was used as a model to study the formation of mutagens that can result from chlorinating waters of high organic content. The Ames Salmonella mutagenicity test was used to evaluate solvent extracts of PCW. Pentane gave satisfactory extraction of mutagens without the emulsion problem encountered with dichloromethane, permitting the use of pentane in continuous extractors. Use of thiosulfate to remove residual chlorine in samples resulted in low mutagenicity. Mutagens were formed within minutes of chlorination and continued to change in amount during the next 1-2 hr. Mutagen formation was affected by pH and was proportional to chlorine dosage.     

K2B4O7-K2SO4-KCl-H2O四元体系288K相平衡研究

采用等温溶解平衡法研究了四元体系K2B4O7-K2SO4-KCl-H2O在288K的相平衡及平衡液相,测定了平衡液相的溶解度及密度。研究结果表明该四元体系为简单共饱和型,无复盐及固溶体形成。根据实验数据绘制了相应的相图。相图中有一个共饱点E,三条单变曲线E1E,E2E和E3E4三个结晶区平衡固相分别为：K2B4O7·4H20,K2SO4和KCl。实验结果表明KCl对K2B4O7·4H2O和K2SO4有盐析作用,并简要讨论了密度变化规律。     

植物乳杆菌LNL2-4-2对互隔交链孢霉的抑制作用

互隔交链孢霉是导致果蔬采后黑斑病的主要病原体。本文采用菌饼法从发酵蔬菜来源的乳酸菌中筛选对互隔交链孢霉有拮抗作用的菌株,利用生理生化及16S rDNA测序鉴定乳酸菌。并进一步观察霉菌孢子超微结构的变化,通过测定霉菌孢子的电导率、丙二醛、可溶性蛋白质及可溶性糖含量的变化,初步探究乳酸菌对互隔交链孢霉的抑制机理。结果表明:植物乳杆菌LNL2-4-2对互隔交链孢霉的抑制率为80.86%,作用最强。采用109 CFU/mL的植物乳杆菌LNL2-4-2菌悬液处理互隔交链孢霉孢子8 h后,其细胞膜完整性降低10.98%,胞外丙二醛、可溶性蛋白质、可溶性糖含量分别增加10.66%,3.10%,11.21%。超微结构分析表明:菌株LNL2-4-2导致互隔交链孢霉的孢子表面皱缩,边缘模糊,顶端破裂,内容物泄漏。在苹果生物防治研究中,贮藏6 d时,浓度为103 CFU/mL的植物乳杆菌LNL2-4-2对互隔交链孢霉造成损伤的抑制率达47.24%。结论:植物乳杆菌LNL2-4-2可作为针对果蔬采后传统杀菌剂的新型替代品。     

Biomarkers of PAH exposure in an intertidal fish species from Prince William Sound, Alaska: 2004-2005

Polycyclic aromatic hydrocarbon (PAH) exposure biomarkers were measured in high cockscomb prickleback (Anoplarchus purpurescens) fish collected from both previously oiled and unoiled shore in Prince William Sound (PWS), Alaska, to test the hypothesis that fish living in the nearshore environment of the sound were no longer being exposed to PAH from the Exxon Valdez oil spill. Pricklebacks spend their entire lives in the intertidal zone of rocky shores with short-term movements during feeding and breeding restricted to an area of about 15 meters in diameter. Fish were assayed for the PAH exposure biomarkers, bile fluorescent aromatic compounds (FAC), and liver ethoxyresorufin O-deethylase (EROD) activity (a measure of cytochrome P450 1A (CYP1A) monooxygenase activity). Bile FAC concentrations and EROD activities were low and not significantly different in fish from previously oiled and unoiled sites. The similar low EROD activity and bile FAC concentrations in fish from oiled and unoiled shores, supports the hypothesis that these low-level biomarker responses were not caused by exposure of the fish to residues of the spilled oil.     

Particle-scale investigation of PAH desorption kinetics and thermodynamics from sediment

Dredged sediment from Milwaukee Harbor showed two primary classes of particles in the <2 mm size range: a lighter-density coal- and wood-derived fraction with 62% of total PAHs and a heavier-density sand, silt, and clay fraction containing the remaining 38% of the PAHs. Room-temperature PAH desorption kinetic studies on separated sediment fractions revealed slow desorption rates for the coal-derived particles and fast desorption rates for the clay/silt particles. The effect of temperature on PAH release was measured by thermal program desorption mass spectrometry to investigate the desorption activation energies for PAHs on the different sediment particles. Three activated diffusion-based models and an activated first-order rate model were used to describe the thermal desorption of PAHs for four molecular weight classes. PAH binding with the coal-derived particles was associated with high activation energies, typically in the range of 115-139 kJ/mol. PAHs bound to the clay/silt material had much lower activation energy, i.e., in the range of 37-41 kJ/ mol for molecular weight 202. Among the desorption models tested, a spherical diffusion model with PAHs located like a rind on the outer 1-3 microm region best described the PAH thermal desorption response for coal-derived particles. This internal PAH distribution pattern on coalderived particles is based on prior direct measurement of PAH locations at the subparticle scale. These studies reveal that heterogeneous particle types in sediment exhibit much different amounts and binding of PAHs. PAHs associated with coal-derived particles aged over several decades in the field appear to be far from reaching an equilibrium sorption state due to the extremely slow diffusivities through the polymer-like coal matrix. These results provide an improved mechanistic perspective for the understanding of PAH mobility and bioavailability in sediments.     

Removal of PAH compounds from liquid fuels by Pd catalysts

Palladium catalysts supported on gamma-alumina (AN, AS), amorphous silica-alumina (ASA), and beta-zeolite (betaZ) were prepared with the aim to reduce the content of polycyclic aromatic hydrocarbons (PAHs) in diesel fuels. The removal of PAH compounds was evaluated with a model feed (toluene, naphthalene, and dibenzothiophene)that approached the composition of diesel fuel. The catalysts were characterized by N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, transmission electron microscopy, temperature-programmed reduction/temperature-programmed oxidation, Fourier transform (FT) IR of absorbed CO, and diffuse reflectance FT spectroscopy of adsorbed NH3. When palladium was supported on ASA instead of AN or betaZ, the intrinsic activity improved considerably. Such behavior is discussed in terms of larger Br?nsted acidity and the degree of reduction of the Pd species on Pd/ASA. For the 2.2 Pd/betaZ catalyst, interaction of the Pd clusters with zeolite protons led to formation of Pddelta+ species, which are not active in the hydrogenation of aromatics. All catalysts were resistant to poisoning by S compounds.     

5-(4-(2-甲氧二氧)苯烯)-2-硫代噻唑-4-酮对雪莲果中酪氨酸酶的抑制作用

通过分光光度法探究5-(4-(2-甲氧二氧)苯烯)-2-硫代噻唑-4-酮(MBTO)对雪莲果中酪氨酸酶的抑制作用。结果表明：MBTO对雪莲果中酪氨酸酶有良好的抑制作用。单因素试验最佳抑制剂浓度为30.0μmol/L、最佳作用时间为210s、最佳作用温度为30℃。通过三因素三水平正交试验,分析得最佳反应条件为：pH7.5、抑制剂MBTO浓度30.0μmol/L、作用时间330s、作用温度30℃,可达到最佳抑制效果,在此条件下MBTO对雪莲果中酪氨酸酶的抑制率达84.24%。     

Na2SO4-H2O2-NaCl加合物工业化生产技术探讨

根据Na2SO4 - H2O2 - NaCl加合物生产工艺和控制要求,结合生产实践,从工艺路线、设备选型、工艺控制等方面进行了探讨.提出了Na2SO4 - H2O2 - NaCl加合物工业化生产技术优化方案.     

Diophantine方程x~2-ty~2=1和y~2-Dz~2=4的可解性(英文)

关于不定方程的可解性研究,是初等数论及代数数论中的重要问题.本文研究了一类二次不定方程组的可解性问题,即:设D是无平方因子正整数,根据Pell方程的性质,运用初等数论方法确定了所有可使方程x2-6y2=1和y2-Dz2=4有正整数解(x,y,z)的D.     

Reactivity enhancement of 2-propanol photocatalysis on SO4(2-)/TiO2: insights from solid-state NMR spectroscopy

Solid-state NMR techniques have been employed to investigate the surface acidic properties of TiO2 and sulfated TiO2, as well as their photocatalytic activities toward 2-propanol. The multinuclear MAS NMR experiments clearly revealed that three different types of Br?nsted acid sites with much stronger acid strength were generated after the sulfation of TiO2. Due to the enhanced Br?nsted acidity, the protonation of 2-propanol can occur more easily, preferentially leading to the formation of Ti-bound 2-propoxy species on the SO42-/TiO2 catalyst The 2-propoxy species can be directly converted to CO2 and thus the photocatalytic activity of sulfated TiO2 catalyst is remarkably enhanced. For comparison, both hydrogen-bonded 2-propanol and Ti-bound 2-propoxy species are present on the TiO2 catalyst with the former being predominant The hydrogen-bonded 2-propanol species are oxidated into acetone molecules that are difficult to further convert into CO2, and the conversion of 2-propoxy species to 2-propanol hampers the direct mineralization of 2-propoxy species on the TiO2 catalyst.     

海洋Arthrobacter protophormiae CDA2-2-2产几丁质脱乙酰酶发酵条件优化

对海洋Arthrobacter protophormiae CDA2-2-2产几丁质脱乙酰酶发酵培养基和发酵条件进行优化,提高发酵产酶水平.在单因素实验优化的基础上,利用PB试验筛选显著影响菌株发酵产酶酶因素,进一步利用响应面法优化这些因素,获得最佳发酵培养基和培养条件.利用单因素实验优化获得碳源、氮源、金属离子、发酵...     

25℃NH3-K2SO4-(NH4)2SO4-H2O体系相平衡的研究

用等温法测定了 2 5℃NH3 K2 SO4 (NH4) 2 SO4 H2 O体系的液固相平衡数据 ,结果表明 ,随着液相中自由氨浓度的增加 ,硫酸钾和硫酸铵的溶解度都在明显降低。依据实验数据绘制的相图 ,提出了氨盐析法从硫酸氢钾水溶液中提取硫酸钾和硫酸铵的生产工艺 ,并对此工艺进行了分析计算。     

The residue behavior of the furazolidone metabolite 3-(4-cyano-2-oxobutylideneamino)-2-oxazolidone in trout

A high-performance liquid chromatography (HPLC)-method for the determination of furazolidone (FZ) and its open-chain cyano-derivative 3-(4-cyano-2-oxobutylideneamino)-2-oxazolidone (M1) in trout is described. Only during the medication period residues of FZ and M1 were detected in the muscle and liver of the trout, which were treated with food containing FZ over a period of 7 days. After the beginning of the withdrawal period, the concentration of FZ and M1 were found to be under the limits of detection.     

Formation of odorous compounds from hydrogen sulphide and 2-butenal

Summary Strongly odorous compounds may be formed upon addition of hydrogen sulphide to unsaturated carbonyl compounds.The reaction between hydrogen sulphide and 2-butenal was studied, and the characteristics of the flavour, the structure and some of the physical chemical characteristics of the reaction products were determinded.The influence of the pH on the type of components formed in dilute aqueous solution was investigated.

---

Bildung riechender Verbindungen aus Schwefelwasserstoff und 2-Butenal

Zusammenfassung Stark riechende Verbindungen können bei der Addition von Schwefelwasserstoff an ungesättigte Carbonylverbindungen entstehen. Die Reaktion zwischen Schwefelwasserstoff und 2-Butenal wurde untersucht und die Charakteristik der Gerüche, die Struktur und einige der physikalisch-chemischen Charakteristiken der Reaktionsprodukte festgestellt. Der Einfluß des pH auf den Typ von in verdünnter wäßriger Lösung entstandenen Komponenten wurde untersucht.

---

---

Part of a paper presented at the Symposium on Aroma Research held at Zeist, The Netherlands, May 26th–29th, 1975.     

Three-ring PAH removal from waste hot gas by sorbents: influence of the sorbent characteristics

Three-ring polycyclic aromatic hydrocarbons (PAH) are one of the most abundant PAH groups emitted during coal combustion. Four of them-acenaphthene (Ac), phenanthrene (Phe), fluorene (Fu), and anthracene (An)-have been listed by the U.S. EPA as priority pollutants. The aim in this paper is to study the abatement of this particular group of three-ring PAH from hot gas emissions during energy generation in coal combustion. The three-ring PAH adsorption capacities are related to the morphological and chemical properties of the 16 sorbents used in this work. Single and multiple linear regressions-principal component regression (PCR)-were applied in this study. The main conclusions reached are, first, that the micropore volume is the most determinant parameter for removal of these PAHs and, second, that the adsorption of three-ring PAH by sorbents from waste hot gas emissions is inversely proportional to their volatility: the lower the PAH volatility, the higher the adsorbent adsorption capacity. The adsorption isotherms show that Phe and An, both examples of PAH with three aromatic rings, behave similarly. However, their behavior differs from that of Ac and Fu, compounds in which only two of their three rings exhibit an aromatic nature.     

固体超强酸SO_4~(2-)/TiO_2-SnO_2催化合成己酸正辛酯

选用己酸和正辛醇为原料,固体超强酸SO2-4/TiO2-SnO2为催化剂,催化合成己酸正辛酯。考察了催化剂制备条件及酯化反应条件对合成反应的影响,并对产品进行了GC-MS、FTIR表征分析。实验结果表明,适宜的固体超强酸催化剂SO2-4/TiO2-SnO2制备条件为:n(TiO2)∶n(SnO2)=5∶1、浸渍液硫酸的浓度为0.75 mol/L、焙烧温度500℃。通过正交实验结果得出己酸正辛酯的优化反应工艺为:酸醇摩尔比1∶1.5、催化剂用量0.45 g(相对于0.05 mol己酸)、带水剂环己烷用量3 mL、反应时间1.5 h。在此条件下,反应的酯化率可达98.2%。     

On-road emission rates of PAH and n-alkane compounds from heavy-duty diesel vehicles

This paper presents the quantification of the emission rates of PAH and n-alkane compounds from on-road emissions testing of nine heavy-duty diesel (HDD) vehicles tested using CE-CERT's Mobile Emissions Laboratory (MEL) over the California Air Resources Board (ARB) Four Phase Cycle. Per mile and per CO2 emission rates of PAHs and n-alkanes were highest for operation simulating congested traffic (Creep) and lowest for cruising conditions (Cruise). Significant differences were seen in emission rates over the different phases of the cycle. Creep phase fleet average emission rates (mg mi(-1)) of PAHs and n-alkanes were approximately an order of magnitude higher than Cruise phase. This finding indicates that models must account for mode of operation when performing emissions inventory estimates. Failure to account for mode of operation can potentially lead to significant over- and underpredictions of emissions inventories (up to 20 times), especially in small geographic regions with significant amounts of HDD congestion. Howeverthe PAH and n-alkane source profiles remained relatively constant for the different modes of operation. Variability of source profiles within the vehicle fleet exceeded the variability due to different operating modes. Analysis of the relative risk associated with the compounds indicated the importance of naphthalene as a significant contributor to the risk associated with diesel exhaust. This high relative risk is driven by the magnitude of the emission rate of naphthalene in comparison to other compounds.     

Formation of bromochlorodibenzo-p-dioxins and furans from the high-temperature pyrolysis of a 2-chlorophenol/2-bromophenol mixture

The homogeneous, gas-phase pyrolytic thermal degradation of a 50:50 mixture of 2-bromophenol and 2-chlorophenol was studied in a 1 cm i.d., fused silica flow reactor at a total concentration of 88 ppm, reaction time of 2.0 s, and temperatures from 300 to 1000 degrees C. Observed products included (in decreasing yield) naphthalene, dibenzo-p-dioxin (DD), phenol, dibenzofuran (DF), bromobenzene, chloronaphthalene, 4-bromo-6-chlorodibenzofuran (4-B,6-CDF), bromonaphthalene, benzene, 4,6-dichlorodibenzofuran (4,6-DCDF), chlorobenzene, 4-monobromodibenzofuran (4-MBDF), 4-monochlorodibenzofuran (4-MCDF), 1-mono-bromodibenzo-p-dioxin (1-MBDD), 2-chloro,4-bromophenol, 2,4-dibromophenol, and 2-bromo-4-chlorophenol. Unlike the case for the pyrolysis of pure 2-chlorophenol, 4,6-DCDF was observed, but the analogous 4,6-DBDF remained undetected similar to the individual results with 2-MBP. This indicates that the presence of bromine increases the concentration of chlorine atoms available for the formation of 4,6-DCDF. Due to bromine atoms acting as better leaving groups than chlorine atoms, the yield of DD was increased over that observed for the pyrolysis of 2-chlorophenol. The addition of bromine to a chlorinated hydrocarbon system results in an increase in the total yield of PCDD/Fs as well as PBDD/Fs and mixed PBCDD/Fs due to the ease of bromine elimination reactions as well as an increase of the chlorine atom concentration.