500米~3生物反应器K_(La)的测定技术

在500米~3活性污泥生物反应器中,用动态测量法测定氧的体积传递系数(K_L a),本文提供了一种简便方法。这种方法对有机废水处理有实用意义。     

Iron(VI) and iron(V) oxidation of copper(I) cyanide

Copper(Il) cyanide (Cu(CN)4(3-)) in the gold mine industry presentsthe biggest concern in cyanide management because it is much more stable than free cyanide. Cu(CN)4(3-) is highlytoxic to aquatic life; therefore, environmentally friendly techniques are required for the removal of Cu(CN)4(3-) from gold mine effluent. The oxidation of Cu(CN)4(3-) by iron-(VI) (FeVIO4(2-), Fe(VI)) and iron(V) (FeVO4(3-), Fe(V)) was studied using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 5HFeO(4-) + Cu(CN)4(3-) + 8H2O - > 5Fe(OH)3 + Cu2+ + 4CNO- +3/202 + 6OH-. The rate law for the oxidation of Cu(CN)4(3-) by Fe(VI) was found to be first-order with each reactant. The rates decreased with increasing pH and were mostly related to a decrease in concentration of reactive protonated Fe(VI) species, HFeO4-. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate constant for the oxidation of Cu(CN)4(3-) by Fe(V) was determined at pH 12.0 as 1.35 +/- 0.02 x 10(7) M(-1) s(-1), which is approximately 3 orders of magnitude larger than Fe(VI). Results indicate that Fe(VI) is highly efficient for removal of cyanides in gold mill effluent.     

Arsenic(III) oxidation by iron(VI) (ferrate) and subsequent removal of arsenic(V) by iron(III) coagulation

We investigated the stoichiometry, kinetics, and mechanism of arsenite [As(III)] oxidation by ferrate [Fe(VI)] and performed arsenic removal tests using Fe(VI) as both an oxidant and a coagulant. As(III) was oxidized to As(V) (arsenate) by Fe(VI), with a stoichiometry of 3:2 [As(III):Fe(VI)]. Kinetic studies showed that the reaction of As(III) with Fe(VI) was first-order with respect to both reactants, and its observed second-order rate constant at 25 degrees C decreased nonlinearly from (3.54 +/- 0.24) x 10(5) to (1.23 +/- 0.01) x 10(3) M(-1) s(-1) with an increase of pH from 8.4 to 12.9. A reaction mechanism by oxygen transfer has been proposed for the oxidation of As(III) by Fe(VI). Arsenic removal tests with river water showed that, with minimum 2.0 mg L(-1) Fe(VI), the arsenic concentration can be lowered from an initial 517 to below 50 microg L(-1), which is the regulation level for As in Bangladesh. From this result, Fe(VI) was demonstrated to be very effective in the removal of arsenic species from water at a relatively low dose level (2.0 mg L(-1)). In addition, the combined use of a small amount of Fe(VI) (below 0.5 mg L(-1)) and Fe(III) as a major coagulant was found to be a practical and effective method for arsenic removal.     

成革中Cr^6＋的测定方法实践

铬与胶原有优异的化学结合性能，在制革中有广泛的应用。但是，近年来发现铬对人体及环境有不良的影响。本文扼要介绍了成革中Cr^6 的测定方法，讨论了不同的外界条件对Cr^ 6含量的影响。     

表没食子儿茶素没食子酸酯的甲基化分子修饰

研究表没食子儿茶素没食子酸酯(EGCG)的甲基化分子修饰。以碘甲烷作为甲基供体,采用化学合成方法研究EGCG 的甲基化分子修饰,并通过HPLC-MS 和NMR 等对反应产物进行结构鉴定。结果表明：采用化学合成方法能有效完成EGCG 的甲基化分子修饰,并分离鉴定出5 个EGCG 甲基化衍生物,分别为4″-Me-EGCG、4′,4″-di-Me-EGCG、5,3′,4′,5′,3″,4″,5″-hepta-Me-EGCG、5,7,3′,4′,3″,4″,5″-hepta-Me-EGCG、5,7,3′,4′,5′,3″,4″,5″-octa-Me-EGCG。     

Control potential of Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) against Lasioderma serricorne (F.) (Coleoptera: Anobiidae)

The control potential of Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) against Lasioderma serricorne (F.) (Coleoptera: Anobiidae) was evaluated in laboratory. The longevity and progeny production of A. calandrae were investigated at 25, 30, and 35 °C. Parasitism preference of A. calandrae to different life stages of L. serricorne was studied at the parasitoid-to-host ratio of 1:15. Effectiveness of A. calandrae against L. serricorne larvae was investigated at different parasitoid-to-host ratios of 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, and 1:40 for 24, 48, and 72 h at a photoperiod of 12:12 (L:D) h, 28 ± 2 °C, and 75 ± 5% RH. Effectiveness of A. calandrae against L. serricorne larvae was also evaluated at different volumes (10, 55, 100, 150, 200, 250, 1500, and 2800 ml) of glass vials when the parasitoid-to-host ratio was 1:15. The favorable temperature for survival and progeny production of female A. calandrae was 25 °C. Female A. calandrae could parasitize mature larvae of L. serricorne and produce their offspring during the whole adult stage of the wasp. Female A. calandrae could control 3-, 4-, 5-, and 6-week-old mature larvae and pupae of L. serricorne. Anisopteromalus calandrae offspring only emerged from 6-week-old mature larvae and pupae of L. serricorne. The parasitoid-to-host ratio and space size dramatically affected the parasitism rate of A. calandrae against L. serricorne and the number of A. calandrae offspring. These results suggest that A. calandrae has great potential for controlling L. serricorne infestation.     

Infestation of dried cassava (Manihot esculenta Crantz) by Prostephanus truncatus (Horn( (Coleoptera: Bostrichidae)

Stored dried cassava is known to become heavily infested by Prostephanus truncatus (Horn). A field study was undertaken in Tanzania to determine the extent of losses that this pest could cause in fermented and unfermented dried cassava roots stored over a period of about 4 months. In fermented roots, the mean weight loss (±SD) rose to 73.6 ± 25.9% over this period compared with 52.3 ± 12.0% in unfermented roots. At each time interval that roots were examined, the weight loss in fermented roots was significantly higher. Subsequent laboratory studies, undertaken to identify some of the factors responsible for this difference between the two types of cassava comprised (1) a determination of the length of larval and pupal development at 27°C and 50 or 70% r.h., (2) adult preference for the two types, and (3) their susceptibility to adult boring. P. truncatus developed at a similar rate in both fermented and unfermented roots, but the adults appeared to prefer the fermented cassava possibly because it was easier to bore into. This was certainly one factor making fermented roots more susceptible to damage by adults. It is concluded that although P. truncatus caused lower weight loss in the unfermented compared with the fermented roots, both were so heavily damaged that it is not worth recommending the storage of one rather than the other. The role of cassava as an intermediate host for P. truncatus is discussed and consideration is given to the need to control the beetle in cassava in order to reduce cross-infestation to maize.     

Reduction of uranium(VI) by mixed iron(II)/iron(III) hydroxide (green rust): formation of UO2 nanoparticles

Green rusts, which are mixed ferrous/ferric hydroxides, are found in many suboxic environments and are believed to play a central role in the biogeochemistry of Fe. Analysis by U LIII-edge X-ray absorption near edge spectroscopy of aqueous green rust suspensions spiked with uranyl (U(VI)) showed that U(VI) was readily reduced to U(IV) by green rust The extended X-ray absorption fine structure (EXAFS) date for uranium reduced by green rust indicate the formation of a UO2 phase. A theoretical model based on the crystal structure of UO2 was generated by using FEFF7 and fitted to the data for the UO2 standard and the uranium in the green rust samples. The model fits indicate that the number of nearest-neighbor uranium atoms decreases from 12 for the UO2 structure to 5.4 forthe uranium-green rust sample. With an assumed four near-neighbor uranium atoms per uranium atom on the surface of UO2, the best-fit value for the average number of uranium atoms indicates UO2 particles with an average diameter of 1.7 +/- 0.6 nm. The formation of nanometer-scale particles of UO2, suggested by the modeling of the EXAFS data, was confirmed by high-resolution transmission electron microscopy, which showed discrete particles (approximately 2-9 nm in diameter) of crystalline UO2. Our results clearly indicate that U(VI) (as soluble uranyl ion) is readily reduced by green rust to U(IV) in the form of relatively insoluble UO2 nanoparticles, suggesting that the presence of green rusts in the subsurface may have significant effects on the mobility of uranium, particularly under iron-reducing conditions.     

Interaction of Phytic Acid with the Metal Ions, Copper (II), Cobalt (II), Iron (III), Magnesium (II), and Manganese (II)

The combination of phytic acid with the metal ions of cobalt (II), magnesium (II), manganese (II), copper (II), and iron (III) has been investigated. With the experimental conditions used, in all cases, the products isolated were amorphous powders with nonstiochiometric atomic ratios.     

羟丙基壳聚糖亚铁配合物的合成

采用壳聚糖先与Fe2+配合,再用环氧丙烷改性,研究了羟丙基壳聚糖-Fe2+的合成工艺,并用紫外和红外光谱对衍生物结构进行了表征。结果表明,在壳聚糖用量为0.1g、Fe2+起始浓度为16mg/mL、溶液pH为2的条件下,制得壳聚糖亚铁配合物。接着在壳聚糖-Fe2+∶环氧丙烷∶25%四甲基氢氧化铵为1mg∶10mL∶0.8mL条件下,制得羟丙基壳聚糖-Fe2+(HPCS-Fe2+)。位于1160～1030cm-1处有特征吸收峰,说明衍生化后得到的HPCS和HPCS-Fe2+上两个羟基上都发生了反应。     

Properties of recycled poly (ethylene terephthalate) (PET)/hyperbranched polyester (HBPET) composite fibers

Hyperbranched polyester (HBPET) with aliphatic–aromatic structure was synthesized and extruded with recycled poly (ethylene terephthalate) (RPET) chips obtained from used water bottles, with ratio of 0.5% and 1?wt% of HBPET. Filament fibers from pure recycled PET (RPET-0) and (RPET-0.5 and RPET-1) composite were spun using a melt spinning process and drawn by a thermal drawing process to improve their mechanical properties. The effects of addition of HBPET on the properties of produced fibers as well as draw ratio are investigated by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (XRD), universal tensile analysis, and sonic velocity. It was found that mechanical properties of the (RPET-0.5 and RPET-1) fibers were improved with respect to pure recycled PET (PET-0) fibers. Moreover, the crystallinity of composites fibers was also increased with an increasing of HBPET content. The improvement in mechanical properties may be due to the increase of orientation of fiber molecules along the fiber axis. Moreover, addition of HBPET serves as lubricant within recycled PET matrix which increased its mechanical properties.     

Reduction of Tc(VII) by Fe(II) sorbed on Al (hydr)oxides

Under oxic conditions, Tc exists as the soluble, weakly sorbing pertechnetate [TcO4-] anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2 x nH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) adsorbed on Al (hydr)oxides [diaspore (alpha-AlOOH) and corundum (alpha-Al2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (M?ssbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11 (diaspore suspension) and 4 days (corundum suspension). M?ssbauer measurements revealed thatthe Fe(II) signal became less intense with Tc(VII) reduction and was accompanied by an increase in the intensity of the Fe(III) doublet and magnetically ordered Fe(III) sextet signals. Tc-EXAFS spectroscopy revealed that the final heterogeneous redox product on corundum was similar to Tc(IV) oxyhydroxide, TcO2 x nH2O.     

Attractancy of diethyl ether extracts of Arachis hypogaea (Linnaeus) (Papilionaceae), Citrullus lanatus (Thunberg) (Cucurbitaceae) and Irvingia gabonensis var. excelsa (Baillon) (Irvingiaceae) to Oryzaephilus mercator (Fauvel) (Coleoptera: Silvanidae)

Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group.

Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract.     

Iron(VI) and iron(V) oxidation of thiocyanate

Thiocyanate (SCN-) is used in many industrial processes and is commonly found in industrial and mining waste-waters. The removal of SCN- is required because of its toxic effects. The oxidation of thiocyanate (SCN-) by environmentally friendly oxidants, Fe(VI) and Fe(V), has been studied anaerobically using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 4HFeO(4-) + SCN(-) + 5H2O-->4Fe(OH)3 + SO4(2-) + CNO(-) + O2 + 2OH-. The rate law for the oxidation of SCN- by Fe(VI) was found to be -d[Fe(VI)]/dt = k11([H+]/([H+] + Ka,HFeO4)) [Fe(VI)][SCN-] where k11 = 2.04 +/- 0.04 x 10(3) M-1 s-1 and pKa,HFeO4 = 7.33. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate of oxidation of SCN- by Fe(V) was approximately 3 orders of magnitude faster than Fe(VI). The higher reactivity of Fe(V) with SCN- indicates that oxidations by Fe(VI) may be enhanced in the presence of appropriate one-electron-reducing agents. The results suggest that the effective removal of SCN- can be achieved by Fe(VI) and Fe(V).     

Contents of vitamins B(1), B(2), B(6), and B(12) in pork and meat products

The concentration of B vitamins (B(1), B(2), B(6), and B(12)) was determined in three pork muscles (Longissimus dorsi, loin; Biceps femoris, ham; and Triceps brachii, shoulder) and in pork and other meat products (cooked, pickled, and cured), of importance because they are consumed in high quantities. The results were compared with values reported by other authors and their contribution to the daily intake of these vitamins estimated. This showed that pork provides, on average, 97, 25.8, 35/43.7 (men/women), and 37% of the RDA (Recommended Dietary Allowances) for vitamins B(1), B(2), B(6), and B(12), respectively.     

Role of transition metals,Fe(II), Cr(II), Pb(II), and Cd(II) in lipid peroxidation

Cod liver oil was oxidized with Fenton-like systems containing transition metals Fe(II), Cr(II), Pb(II), and Cd(II). Malonaldehyde (MA) formed from 10 μl cod liver oil oxidized by a Fenton-like system containing each metal at levels of 0.25, 0.5, 1 and 4 μmol was analyzed by a gas chromatograph equipped with a nitrogen phosphorus detector. The MA production exhibited dose response and the greatest amount (837.0 ± 19.1 nmol) was obtained by the Fe(II) system at the level of l μmol. Generally, higher MA formation is observed in the lower the third ionization potential of the metal. The decreasing order of MA formed in the metal systems at the level of 1 μmol is Fe(II) > Cr(II)(274.1 ± 20.1 nmol) > Pb(II)(150.7 ± 13.0 nmol) > Cd(II)(95.4 ± 6.7 nmol). The amounts of MA formed in Cr(II), Pb(II), and Cd(II) systems were considerably lower than those in the Fe(II) system. The relative formations of MA in the Cr(II) and Pb(II) systems were similar to those in the Fe(II) system. The results suggest that trace amounts of metals contribute oxidative effects to lipid peroxidation followed by various diseases.     

Supercritical fluid extraction (SFE) of 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI) from ground-coffee with high-performance liquid chromatographic-electrospray mass spectrometric quantification (HPLC/ESI-MS).

Two polar analytes, 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI), were extracted with supercritical carbon dioxide (CO2) modified with aqueous methanol. The method was applied to a roasted coffee powder with good recovery rates. Method efficiency was compared with that of solid-phase extraction using SCX Disc cartridges and validated for spiked solid matrix. The analytes were determined using isocratic liquid chromatography-mass spectrometry (LC/MS) on an Atlantis HILIC Silica column (150 x 2.1 mm, 3 microm) with 80% methanol and 20% 0.01 mol l-1 ammonium formate as the mobile phase. The limit of quantification was around 1.5 pg for 4-MeI and 2.0 pg for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients of >0.999. The coefficient of variation for the intra-day and inter-day precisions was <4% (n = 6). Accuracy was in the range 98-101%; recovery rates were > or = 98 and > or = 99% for THI and 4-MeI, respectively. Several samples of Arabica coffee from various locations and commercially available 'off-the-shelf' coffee products (Arabica/Robusta mixtures) were analysed to test the method.     

Genetics of bruchid (Callosobruchus maculatus Fab.) resistance in cowpea (Vigna unguiculata (L.) Walp.)

Bruchid resistance has been measured using a variety of techniques. Mean development period (MDP) and percentage adult emergence (PAE) are two of the more important traits measuring bruchid (Callosobruchus maculatus Fab.) resistance in cowpea. The objective of the study was to evaluate the genetic relationship between MDP and PAE in C. maculatus resistant cowpea. Seventy-two F₂ population plants were developed from the cross between C. maculatus resistant TVu-11953 (with delayed MDP and low PAE) and C. maculatus susceptible Ife Brown (with early MDP and high PAE) which were evaluated for resistance to cowpea C. maculatus. MDP at 45 days after infestation (DAI) and PAE at 60 DAI were taken as analysed measures for resistance to C. maculatus infestation. Data generated were subjected to chi-square analysis. Varied resistant response to C. maculatus infestation was observed among the F₂ generation plants but their responses showed inclination to the susceptible parent. A 15:1 ratio for susceptible to resistant genotypes was observed with MDP among the F₂ genotypes evaluated which is an indication of the presence of two recessive genes that control of MDP. The segregation of PAE also showed a 15:1 ratio goodness of fit (P > 0.05) for susceptible to resistant genotypes. Test of independence between MDP and PAE was not significant (χ² = 2.19, P = 0.19). This study revealed that the recessive genes controlling these two traits (MDP and PAE) were independently assorted and showed no linkage. This was also evident in the observed F₂ genotypes with C. maculatus resistance expressing either delayed MDP or low PAE and not both in the study.     

Reactivity of Pb(II) at the Mn(III,IV) (oxyhydr)oxide--water interface

In this study, the reactivity of lead (Pb(II)) on naturally occurring Mn(III,IV) (oxyhydr)oxide minerals was evaluated using kinetic, thermodynamic, and spectroscopic investigations. Aqueous Pb(II) was more strongly adsorbed to birnessite (delta-MnO1.7) than to manganite (gamma-MnOOH) under all experimental conditions. The isoteric heat of Pb adsorption (delta HT) or birnessite was 94 kJ mol-1 at a surface loading of 1.1 mmol g-1, and decreased with increasing adsorption density. This indicated that adsorption was an endothermic process and that birnessite possessed heterogeneous sites of reactivity for Pb. X-ray absorption fine structure (XAFS) spectra revealed that Pb was adsorbed as inner-sphere complexes on both birnessite and manganite with no evidence to suggest oxidation as an operative sorption mechanism. Lead appeared to coordinate to vacancy sites in the birnessite layer structure with concurrent release of Mn to solution, which resulted in a greater number of second shell Mn scatterers in Pb-birnessite when compared to Pb-manganite samples. The difference in Pb coordination apparently explained the contrasting desorption behavior between the two Mn minerals. These results have significant implications for Pb partitioning in soil environments containing solid-phase Mn(III,IV) (oxyhydr)oxides.     

Cu~(2+)、Fe~(2+)和Fe~(3+)对红曲霉液态发酵产色素影响

采用液体发酵研究了三种金属离子Cu~(2+)、Fe~(2+)和Fe~(3+)对红曲霉发酵代谢产色素的影响。添加不同浓度的CuSO_4溶液、FeSO_4·7H_2O溶液和FeCl_3溶液到培养基中发酵培养,测量发酵液中的红曲色素色价,进行对比分析,发现当CuSO_4溶液浓度逐渐增大时,红曲色素的色价逐渐降低;当Fe~(2+)逐渐增加时,色素含量上升;当添加Fe~(3+)后,色素含量不稳定。因此,Cu~(2+)和Fe~(3+)不适合作为优化培养基的金属离子,Fe~(2+)利于色素生成,合适的FeSO_4添加浓度为0.05 mmol/L。