Mo In Solution Research Articles

Synthesis of Cu2O/T-ZnOW nanocompound and characterization of its photocatalytic activity and stability property under UV irradiation

Cu2O/tetrapod-like ZnO whisker (T-ZnOW) nanocompound was synthesized by a simple hydrothermal chemical method. The chemical composition, morphology, band gap and photocatalytic property of the Cu2O/T-ZnOW nanocompound were studied in detail. It was observed that the Cu2O particles deposited on T-ZnOW surface had a cubic structure and the crystallinity of T-ZnOW did not change with the increase of Cu2O crystals. The morphology and content of Cu2O in the Cu2O/T-ZnOW nanocompound played an important role on the photocatalytic activity. In addition, the coexistence of Cu2O and T-ZnOW nanoparticles was propitious to the high photocatalytic activity owing to their hetero-junction effect. The Cu2O/T-ZnOW nanocompound prepared by 7.2% Cu/Zn MR exhibited the best photocatalytic activity on the degradation of MO solution under UV light irradiation. At the first 100 min of irradiation, the photodegradation efficiency of MO solution reached up to 99.16%, which still retained its high photocatalytic activity about 89.10% even at the end of the fourth cycle. Little change was found in their phase compositions after the photocatalytic reaction process, except partial oxidation of particles’ surface. The mechanism for UV light driven photocatalytic activity enhancement over Cu2O/T-ZnOW nanocompound was discussed.

Study of irradiated mod.9Cr–1Mo steel by synchrotron extended X-ray absorption fine structure

Synchrotron extended X-ray absorption fine structure (EXAFS) spectroscopy measurements were performed to study the dose dependence of and alloying effects on irradiation-induced changes in the local atomic environments in a mod.9Cr–1Mo ferritic-martensitic steel. The measurements were carried out at room temperature on non-irradiated and irradiated specimens exposed to 1, 4, and 10 displacement per atom (dpa) at 40–70°C. The EXAFS data for Fe, Cr, Mo, and Nb K-edges were recorded, and the local structure close to the X-ray absorbing atom was determined. Irradiation caused significant reductions in peak amplitude in the Fe, Mo and Nb K-edge Fourier transformed EXAFS. The data showed a systematic decrease in coordination number of neighbor atoms with increasing irradiation dose, and the dose dependence of the coordination loss was dependent on the specific element. The measured damage around Fe sites can be correlated with the dpa value, while the loss of near neighbors around Mo saturated at ∼1dpa. The coordination in the Fe matrix was reduced less by irradiation than either the coordination of Mo in solution or Nb in carbides. It was demonstrated that EXAFS can provide a detailed, atomic level description of radiation damage in complex alloy systems.

Barrierless Cu-Ni-Mo Interconnect Films with High Thermal Stability Against Silicide Formation

Cu-Ni-Mo alloys were investigated to increase thermal stability against silicide formation. The alloy compositions were chosen such that an insoluble element (Mo) solute was dissolved into Cu via a third element Ni which is soluble in both Cu and Ni. Thin-film Cu-Ni-Mo alloys were prepared by magnetron sputtering. The films with Mo/Ni ratio of 1/12 exhibited low electrical resistivities in combination with high thermal stabilities against silicide formation, in support of a tentative “cluster-plus-glue-atom” model for stable solid solutions. In particular, a (Mo1/13Ni12/13)0.3Cu99.7 sample reached a minimum resistivity of 2.6 μΩ cm after 400°C/1 h annealing and remained highly conductive with resistivities below 3 μΩ cm even after 400°C/40 h annealing. These alloys are promising candidates for future interconnect materials.

Selective extraction of Mo using Cyanex-272 and tributyl phosphate from low grade Ni–Mo ore leach liquor

Selective extraction of Mo by Cyanex-272 and tributyl phosphate (TBP) was investigated from the leach liquor of a low grade Ni–Mo ore, which contains mainly Mo(VI), Fe(III), Ni(II) and a small quantity of other impurities. The elements in the leach liquor were divided into four groups based on the extraction mechanism of acid phosphorus extractants, and the behavior of four elements (Mo, Fe, As and V) was investigated. The separation factors of Mo to Fe, As and V were calculated separately using di-2-ethylhexylphosphoric acid, 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester and bis(2,4,4-trimethylpentyl)phosphine acid (Cyanex-272) under the same conditions. Cyanex-272 was found to be the optimum extractant. The synergistic coefficients of Cyanex-272 and co-solvents (secondary caprylic alcohol and TBP) were calculated separately for the extraction of Mo, Fe, As and V and TBP was found to be the better choice. Several operational factors such as initial leach liquor pH, extractant concentration, co-solvent concentration and stripping reagent concentration were examined to establish suitable conditions for the effective extraction and stripping of Mo. The separation factors, βMo/Fe=1803.61, βMo/As=480.09 and βMo/V=103.22, were obtained under the optimum experimental conditions of 15%(v/v) Cyanex-272, 15%(v/v) TBP, initial leach liquor pH of 0.0 and organic/aqueous (O/A) phase ratio of 1.0. The theoretical number of stages required for extraction and stripping was determined from the McCabe–Thiele diagrams. Molybdenum (11.62g/L) was extracted in five stages with an O/A ratio of 1.0, yielding a raffinate with only 0.30g/L Mo. Three stripping stages yielded a 98.0% Mo stripping efficiency from 11.23g/L Mo loaded organic phase, producing an enriched 55.05g/L Mo solution that contained 0.058g/L As and 0.023g/L V. A high purity final MoO3 product (99%) was obtained by re-crystallization from the stripped Mo solution.

Fabrication and High Visible Light Photocatalytic Properties of Cu/Cu2O Nanocomposites by the One-Pot Solution-Phase Hydrothermal Method

Cu/Cu2O nanocomposites were synthesized by the one-pot solution-phase hydrothermal method. The resulting products were characterized by X-ray diffraction, field emission scanning electron microscope and X-ray photoelectron spectroscopy. Experimental results indicate that the content of Cu in the Cu/Cu2O CNs increasing with prolonged reaction time. The content of Cu in the Cu/Cu2O CNs plays an important role in the photocatalytic activity. The coexistence of Cu2O and Cu nanoparticles was propitious to the high photocatalytic activity owing to their hetero-junction effect. Compared with the Cu/Cu2O CNs with high Cu content (68-96 wt%) and pure Cu2O, the Cu/Cu2O CNs with low Cu content (2.1-9.2 wt%) exhibited improved photocatalytic activity on the degradation of MO solution under visible light irradiation, at the first 20 min of irradiation, the photodegradation efficiency of MO solution reach up to 99%, it is still as high as 95% even at the end of the fourth cycle. Little change is found in their phase compositions during the photocatalytic reaction process, except partial oxidation of particles surface. The HmechanismH for visible light driven photocatalytic activity enhancement over Cu/Cu2O CNs is discussed.

Research of Adsorption Performance of V (V) and Mo (VI) on Collagen Fiber Immobilized Bayberry Tannin

The adsorption behaviors of V(V) and Mo(VI) on the collagen fiber immobilized bayberry tannin (IBT), a new kind of adsorption, were investigated. It was found that at 323K, pH=2.0, the adsorption capacities of V(V) on 0.100g adsorbent was 1.03mmol/g in 100ml of 1.960mmol/L V(V) solution, and that of Mo(VI) was 0.86mmol/g at 323K, pH=4.0, with 100ml of 1.042 mmol/L Mo(VI) solution. The effect of pH on the adsorption capacity of V(V) and Mo(VI) was conspicuous. The adsorption capacity of Mo(VI) decreased with pH increasing, and the maximal adsorption capacity of V(V) was observed at pH4.0. Langmuir equation was used for the description of adsorption isotherms of V(V), while Freundlich equation could be well described that of Mo(VI). The adsorption kinetics of V(V) and Mo(VI) can be well described by the pseudo-second-order-rate model and the adsorption capacities calculated by this model are very close to those experimentally determined. The adsorbent can be regenerated by using 0.1mol/L HCl and 0.02mol/L EDTA in tune as desorption agent after the adsorption of V(V) and Mo(VI). In the desorption process V(V) and Mo(VI) were utilized respectively. These facts implies that the adsorbent can be used for the separation of V(V) and Mo(VI) in aqueous.

Rapid dendrite growth subjected to multi-solute trapping in an undercooled Fe-based quaternary alloy

The influence of multi-solute trapping on dendrite growth remains unclear yet. In this paper, rapid solidification of Fe-5Ni-5Mo-5Ge (wt.%) alloy was accomplished to investigate (αFe) dendrite growth involving three solutes. The dendrite growth velocity increases sluggishly and then rapidly with the rise of undercooling. Compared with Ni and Mo solutes, Ge solute plays the dominant role on the sluggish dendrite growth within a wide moderate undercooling range. All the solutes promote the rapid dendrite growth at a higher undercooling. The segregationless dendrite growth was achieved due to multi-solute trapping effect at the maximum experimental undercooling.

Assay of enzymes forming AMP + PPi by the pyrophosphate determination based on the formation of 18-molybdopyrophosphate

The formation of 18-molybdopyrophosphate anion has been studied to develop a simple and rapid assay of the enzymatic reaction involving ATP → AMP + PPi ( P 2 O 7 4 - ) . By the addition of P 2 O 7 4 - anion to an acidic acetonitrile–water solution containing MoO 4 2 - anion, the colorless Mo(VI) solution immediately became yellow due to the formation of 18-molybdopyrophosphate anion. The absorbance of the P 2 O 7 4 - – Mo ( VI ) mixture at, for example, 450 nm was proportional to the analytical concentration of P 2 O 7 4 - anion. Although the test Mo(VI) solution remained colorless by the addition of AMP, it gradually turned to yellow by ATP. The undesired color development is attributed to the formation of a yellow molybdophosphate species accompanied by the dissociation of PO 4 3 - from the unstable ATP molecule. However, the color development became much slower when ethylenediaminetetraacetic acid was added into an assay mixture, where ATP may form a kinetically stable species. Thus, P 2 O 7 4 - anion can be determined spectrophotometrically in the enzymatic reaction mixture containing ATP. By the addition of ascorbic acid, the yellow P 2 O 7 4 - – Mo ( VI ) mixture turned to blue due to the reduction of the molybdopyrophosphate anion. Thus, P 2 O 7 4 - anion can be detected colorimetrically by the blueness. The spectrophotometric and colorimetric methods could be applied advantageously to the assay of acetyl-CoA synthetase.

Spectrophotometric Determination of Phosphate Anion Based on the Formation of Molybdophosphate in Ethylene Glycol-Water Mixed Solution

New appropriate reaction system was found for spectrophotometric determination of phosphate anion. This spectrophotometric method is based on the color development due to the formation of yellow molybdophosphate anion in acidic ethylene glycol-water (EG-W) mixed solution containing Mo(VI) species. The solution containing e.g. 20 mM Na(2)MoO(4), 0.1 M HCl, and 40% (v/v) EG is colorless, and becomes immediately yellow by addition of phosphate anion. Thus the method is simple, rapid, and easy to carry out. Although Si(IV) species is well known to interfere with the determination of phosphate anion in many cases, the EG-W Mo(VI) solution remains colorless after addition of silicate anion at 1 mM level, indicating that no yellow molybdosilicate anion was formed in the EG-W solution. Under an optimized condition, the absorbance at e.g. 400 nm of the EG-W P(V)-Mo(VI) solution was proportional to the concentration of phosphate anion with good reproducibility, and the detection limit was 1 µM. Also the present method is less interfered by high concentrations of potassium and ammonium cations and oxidative nitrite anion as well as silicate anion.

Adsorption onto activated carbon for molybdenum recovery from leach liquors of exhausted hydrotreating catalysts

This paper investigated molybdenum recovery from acid leach liquors of exhausted hydrotreating catalysts. Adsorption onto activated carbon was used to separate molybdenum from other metals contained in these leach liquors, namely nickel, cobalt and vanadium.Kinetic tests using Mo-bearing solutions denoted that the rate of adsorption depends on the amount of Mo in solution with an estimated order of reaction of 0.9±0.3.Equilibrium sorption tests showed that metal accumulation presents a bell-shaped behaviour as pH changes with a maximum sorption capacity around pH 5. Preliminary test in column reactor fed with Mo-bearing solution confirmed the sorption capacity estimated in batch tests (0.230g/g).Sorption tests in batch reactors using leach liquor ([Mo]=3.06g/L, [V]=5.84g/L, [Ni]=4.48g/L, [Al]=1.77g/L) denoted that Mo can be quantitatively and selectively removed from solution (99% removal for Mo, 24±2% for Al, 19% for V and 0% for Ni) with no significant reduction of sorption capacity towards Mo (0.250g/g).Preliminary sorption–desorption cycles denoted that Mo removal was larger than 90% in each cycle, whilst the other metals were minimally removed (Al and V) or completely rejected (Ni).

Preferences for fat and basic tastes and in 3-, 6- and 12-month-old infants

Fat perception received recent interest, but fat preference in human infants is a matter of debate. The objective here was to investigate fat and taste preferences in the same infants (N= 66) at 3, 6 and 12 months. Preference for a fat solution (sunflower and rapeseed oils mixed with soy lecithin) and for taste solutions (sweet, lactose; salty, NaCl; bitter, urea; sour, citric acid; umami, sodium glutamate) was evaluated. The same method was applied at each age. Mothers and their infant participated in 2 videotaped sessions, during which the 5 taste and fat solutions were assessed in a balanced order. For each taste, 4 bottles (water, tastant, tastant and water) were presented by the experimenter.Twoglobal indices were calculated to represent acceptance of the tastant relatively to water (W), based on ingested volumes and on facial expressions. At 3 and 6 mo, the fat solution was as consumed as W; but less than W at 12 mo; at all ages it elicited ‘negative’ expressions. For taste solutions, at 3 mo the sweet solution was more and the bitter one wasless consumed thanW;the bitter and the sour solutions elicited ‘negative’ expressions. At 6 and 12 mo, the sweet and salty solutions were more consumed than W and elicited ‘positive’ expressions; the bitter and sour solutions elicited negative expressions. Infants were indifferent to the umami solution. These findings are in accordance with the literature on taste preference but the indifference or rejection of the fat solution raise questions about an ‘innate’ preference for fat. The olfactory component of fat might be involved in this rejection.

Microstructure and Properties of Mo Microalloyed Cold Rolled DP1000 Steels

Two kinds of ultra-high strength cold rolled dual phase steels have been developed by designing C-Si-Mn-Cr and C-Si-Mn-Cr-Mo alloy systems. Tensile strength and elongation of both steels exceed 1100 MPa and 10%, respectively. The microstructures of both steels consist of massive martensite and ferrite. And the massive martensite of Mo-free steel disperses in the ferrite with volume fraction of 64%. However, the massive martensite of Mo-containing steel is connected or closed by small martensite islands each other, and martensite volume fraction is 69%. As to Mo-free steel, the yield strength, yield ratio, and work hardening exponent n are 548 MPa, 0.49, and 0.26, respectively. As for Mo-containing one, the yield strength, yield ratio, and n value are 746 MPa, 0.66, and 0.33, respectively. Besides, the ferrite of Mo-free steel is deformed at the initial stage of plastic deformation. However, for Mo-containing one, Mo solution strengthened ferrite and small overaged martensite islands are deformed preferentially at small strain, which causes the yield strength to reach approximately 200 MPa higher than that of Mo-free steel.

Interfacial Impregnation Chemistry in the Synthesis of Molybdenum Catalysts Supported on Titania

A thorough study is presented concerning the interfacial chemistry of the impregnation step involved in the preparation of molybdenum(VI) supported titania catalysts. This is based on a recently developed picture for the “titania/electrolyte solution” interface. In the frame of this work, we investigated the mode of interfacial deposition of the Mo(VI) oxo-species at the titania/electrolytic solution interface, the Mo(VI) interfacial speciation, and the structure of the deposited Mo(VI) oxo-species. Several methodologies based on potentiometric titrations, microelectrophoretic mobility, and macroscopic adsorption measurements were applied. The deposition model developed describes very well the experimental “proton−ion” linear curves and the “adsorption edges”. Moreover, it was verified by laser Raman spectroscopy. At Mo(VI) solution concentration up to 3 × 10−2 M and in the pH range 9−5, the mounted Mo(VI) is practically deposited as monomer MoO42− species in two configurations: an inner sphere mononuclear monosubstituted complex with the terminal surface oxygen atoms of titania [TiOMoO3]0.35− and a surface species where the MoO42− ions are retained above a bridging surface hydroxyl through a hydrogen bond [Ti2OH···O−MoO3]1.57−. In both configurations, the Mo atom is situated between the surface plane and plane 1, whereas the solution oriented oxygen atoms are situated at plane 1 of the compact layer of the interface. The concentration of the [Ti2OH···O−MoO3]1.57− increases with pH, while the concentration of the [TiOMoO3]0.35− decreases. Thus, at pH > 8, the [Ti2OH···O−MoO3]1.57− predominates, whereas at pH < 5.5 the [TiOMoO3]0.35− is the most important species. In the pH range 5−4 and for the maximum initial Mo(VI) solution concentration, the contribution of the polymer species to the whole deposition process is not negligible. The deposited polymer species, Mo7O246− and HMo7O245−, are adsorbed through electrostatic forces and located in a range extended from plane 1 up to the first layers of the stagnant-diffuse layer being close to plane 2 of the interface. The adsorption sites involve five bridging and five terminal neighboring (hydr)oxo-groups. A preferential deposition of the monomers, MoO42−, with respect to the polymer ones was generally found. The above findings could prove useful for controlling the impregnation-equilibration step involved in the preparation of the molybdenum supported titania catalysts by equilibrium deposition filtration.

Extraction of molybdenum from supersaturated solutions in nitric acid with tributyl phosphate solutions

Data were obtained on the composition of saturated Mo solutions in HNO3 solutions of various concentrations at various temperatures, with a maximum at 5 M HNO3. Extraction of Mo from such solutions of low acidity with concentrated solutions of TBP in xylene at room temperature was studied, and the IR spectra of the extract were measured. The extractability of Mo in the supersaturation region sharply decreases with a decrease in the TBP concentration and with an increase in the acidity of the aqueous phase. The kinetics of the Mo extraction is described by a first-order rate equation. The process apparently involves formation of molybdic acid in the aqueous phase by the reaction MoO2(OH)+ + H2O = H2MoO4 + H+. It is assumed that H2MoO4 dissolves in water present in TBP, instead of precipitating from the aqueous phase.

Photocatalyst of TiO 2/ZnO nano composite film: Preparation, characterization, and photodegradation activity of methyl orange

The TiO 2/ZnO nano composite film with atomic ratios of Ti/(Ti + Zn) of 100%, 75%, 50%, 25%, and 0% was successfully prepared via sol–gel process from directly mixing TiO 2/ZnO sol followed by heat treatment at 500 °C for 2 h in air. The SEM observation and the XRD measurement revealed that the microstructural morphology and the crystallization behavior of the composite film were essentially related to the atomic ratio of Ti/(Ti + Zn). The UV irradiated degradation of MO solution using the composite film as catalyst showed a linear tendency of the photocatalytic activity of the film against the value of Ti/(Ti + Zn). An exception to photocatalytic activity was observed for the film with Ti/(Ti + Zn) of 75%, which has been attributed to the poor crystallization of the film. Heat treatment with 5 h was applied to the film and better crystallization was achieved for the film. Consequently, a substantial improvement of the photocatalytic activity for the film was finally achieved.

EFFECT OF ON-FARM SEED PRIMING ON YIELD AND SEED QUALITY OF BEAN (Phaseolus vulgaris L.)

Two field experiments were carried out during the two summer growing seasons of 2006 and 2007, at El-Baramoon Farm, Mansoura Horticultural Research Station, Dakahlia Governorate, Egypt, to investigate the effect of on-farm seed priming for different periods in water or in molybdenum (Mo) solution on growth, yield and pod characters as well as seed yield and its quality of snap bean (Phaseolus vulgaris L.) cv. Bronco. Nine treatments were arranged in complete randomized block design with 3 replicates. Results indicated that priming bean seeds in Mo solution or water significantly increased the capability of the plants to produce vigorous vegetative growth expressed as plant height, number of branches and number of leaves per plant, plant fresh and dry weight as well as chlorophyll content. All priming treatments enhanced the total green plant yield, especially priming for 9 hours in Mo solution or water. These treatments gave the highest values for yield. Seed yield and its quality were also improved as a result of using seed priming treatments. Generally, On-farm seed priming seems to be a widely applicable technology and can be used to add to the benefits achieved by using improved modern varieties or by adoption of other improved technologies such as fertilizer or better crop protection. This low-cost, low-risk technology is good insurance for farmers by providing low-cost more options and improvements to their livelihoods.

Tungsten affects the cortical microtubules of Pisum sativum root cells: experiments on tungsten-molybdenum antagonism.

Tungsten (W) is increasingly shown to be toxic to various organisms, including plants. Apart from inactivation of molybdo-enzymes, other potential targets of W toxicity in plants, especially at the cellular level, have not yet been revealed. In the present study, the effect of W on the cortical microtubule array of interphase root tip cells was investigated, in combination with the possible antagonism of W for the pathway of molybdenum (Mo). Pisum sativum seedlings were treated with W, Mo or a combination of the two, and cortical microtubules were examined using tubulin immunofluorescnce and TEM. Treatments with anti-microtubule (oryzalin, colchicine and taxol) or anti-actomyosin (cytochalasin D, BDM or ML-7) drugs and W were also performed. W-affected cortical microtubules were low in number, short, not uniformly arranged and were resistant to anti-microtubule drugs. Cells pre-treated with oryzalin or colchicine and then treated with W displayed W-affected microtubules, while cortical microtubules pre-stabilized with taxol were resistant to W. Treatment with Mo and anti-actomyosin drugs prevented W from affecting cortical microtubules. Cortical microtubule recovery after W treatment was faster in Mo solution than in water. The results indicate that cortical microtubules of plant cells are indirectly affected by W, most probably through a mechanism depending on the in vivo antagonism of W for the Mo-binding site of Cnx1 protein.

Influence of Soil Solution Salinity on Molybdenum Adsorption by Soils

Molybdenum (Mo) adsorption on five arid-zone soils from California was investigated as a function of equilibrium solution Mo concentration (0-30 mg L), solution pH (4-8), and electrical conductivity (EC = 0.3 or 8 dS m). Molybdenum adsorption decreased with increasing pH. An adsorption maximum was found near pH 4. Molybdenum adsorption as a function of solution pH was independent of solution salinity from pH 4 to 8. Molybdenum adsorption for five soils as a function of solution Mo concentration conformed to the Langmuir adsorption isotherm equation. The Mo adsorption maxima obtained with the Langmuir equation for both ECs were not statistically significantly different at the 95% level of confidence, with the exception of one soil. The constant capacitance model, a surface complexation model, was able to describe Mo adsorption as a function of solution Mo concentration and solution pH. Molybdenum adsorption was predicted using the soil chemical properties cation exchange capacity, organic carbon content, inorganic carbon content, and iron oxide content. These results are advantageous, as they indicate that, under agricultural conditions (pH 4-8), Mo adsorption can usually be described without consideration of changes in soil solution salinity.

The effect of alloying elements on constrained carbon equilibrium due to a quench and partition process

Abstract The model proposed by Speer et al. to calculate the constrained carbon equilibrium is expanded to include any number of substitutional solutes and coded with the MatLab and Thermo-Calc programs. This model is used to evaluate the effect of Al, Cr, Cu, Mn, Mo, Ni and Si solutes on the final austenite carbon concentration of ternary Fe – X – C alloys. Comparison is also made with the carbon concentration measured experimentally in some Transformation Induced Plasticity steels.

Studies of Ni–Mo electrodeposited alloys with polymers by Auger electron spectroscopy

AbstractThe aim of this paper is the presentation of crystalline and band‐structure studies of electrodeposited Ni–Mo alloys with different polymers. Composites based on Ni–Mo alloys with polythiophene, polypyrrole and polyethylene were obtained by electrochemical methods. The structural analysis made by X‐ray diffraction shows that a solid solution of molybdenum in nickel is forming. The analysis of the diffraction line broadening indicates the presence of the Ni–Mo solution nanocrystallites in the deposited layers. The analyses of valence‐band Auger spectra have also shown that the change of electronic parameters is due to the presence of polymer elements. The existence of surface and bulk plasmons verifies the oxidized substrate with an average dielectric constant. (© 2008 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)