Concentration Of Ammonium Molybdate Research Articles

Synthesis of sodium alginate/polyacrylamide photochromic hydrogels with quadruple crosslinked networks.

Photochromic hydrogels have great potential for inkless printing, smart display devices, anti-counterfeiting and encryption. However, the short information storage time limits their large-scale application. In this study, a sodium alginate/polyacrylamide photochromic hydrogel with ammonium molybdate as the color change factor was prepared. The addition of sodium alginate was beneficial to the improvement of the fracture stress and elongation at break. In particular, when the content of sodium alginate was 3%, the fracture stress increased from 20 kPa without sodium alginate to 62 kPa. Different photochromic effects and information storage times were achieved by regulating the calcium ion and ammonium molybdate concentration. And the hydrogel with an ammonium molybdate immersion concentration of 6% and calcium chloride immersion concentration of 10% can store information for up to 15 h. At the same time, the hydrogels were able to maintain their photochromic properties over five cycles of "information writing - erasure" and achieved "hunnu" encryption. Therefore, the hydrogel shows excellent information controllable erasure properties and encryption functions, indicating its broad application prospects.

Theoretical calculation and experimental validation of ammonium molybdate concentration for fruit ripeness indicator label

It is indicated from the previous research that indicator label of fruits ripeness made from ammonium molybdate does not change color according to fruit maturity. The color change in the ripeness indicator label is due to the reaction between ethylene gas (C2H4) emitted from fruits and ammonium molybdate [(NH4)6Mo7O24.4H2O] added into the label. The reaction produces molybdenum blue that turns the color of ammonium molybdate from yellow to blue. This research is approached based on the theoretical calculation of the requirement of ammonium molybdate as a change color in the label and then it is validated in the laboratory. Theoretical calculations of ammonium molybdate reaction with ethylene gas are based on stoichiometry. The result shows that 1 gram of ammonium molybdate reacts with 0.136 gram ethylene gas. The oxidation number of Mo decreased from Mo(VI) in the form of [Mo8O26]4- to Mo(V) in the form of [Mo8O22(H2O)2]4-. The experimental validation in this study is carried out by exposing the label containing ammonium molybdate with ethylene gas into tightly closed jar. At the beginning of the storage, the label was yellow but at the end of the storage, the label color changed to reddish brown either for the sample exposed with ethylene or without ethylene. This research is continued by increasing the RH of the jar to 85% and the result shows that the label turned green at the end of storage. The performance of the label as ripeness indicator is also tested by sticking label in the jar where 1 kg of banana had been previously stored. The label indicates change in color from yellow to dark blue thus it is concluded that the label resulted from this research is potential to be used as ripeness indicator for fruits.

Specific H+ level is crucial for accurate phosphate quantification using ascorbate as a reductant.

Owing to its essentiality for cellular metabolism, phosphate (PO43-) plays a pivotal role in ecosystem dynamics. Frequent testing of phosphate levels is necessary to monitor ecosystem health. Present investigations were aimed to identify the key factors that are essential for proper quantification of PO43-. Primarily, H+ levels played a critical role in the development of molybdenum blue complex by ammonium molybdate and PO43- with ascorbic acid as a reductant. Molybdenum blue complex formed in the presence of 8 to 12mmol of H+ in 3ml reaction mixture remained stable even after 72h. Of different concentrations of ammonium molybdate and ascorbic acid tested, best molybdenum blue complex was formed when their concentrations were 24.3 and 5.68μmol, respectively. More or less similar intensity of molybdenum blue complex (due to reduction of phosphomolybdic acid and not molybdic acid) was formed in the presence of H+ at levels ranging from 8 to 10mmol in 3ml reaction mixture. Our findings unequivocally demonstrated that (i) the reaction mixture containing 3% ammonium molybdate, 0.1% ascorbic acid and 5M H2SO4 in the ratio of 1:1:1 is ideal for PO43- quantification; (ii) antimony (Sb) significantly curbs the formation of molybdenum blue under these ideal conditions; (iii) this fine-tuned protocol for PO43- quantification could be extended without any problem for determining the level of PO43- both in plant as well as soil samples; and (iv) Azotobacter possesses potential to enhance levels of total PO43- in leaves and grains and soluble/active PO43- in rhizosphere soils of wheat.

Convenient one step synthesis of molybdenum carbide embedded N-doped carbon nanolayer hybrid architecture using cheap cotton as precursor for efficient hydrogen evolution

The development of low-cost and highly efficient hydrogen evolution reaction (HER) catalysts has driven continuous effort. Here we develop a one-step preparation method of novel two-dimensional coupled hybrid of molybdenum carbide embedded N-doped carbon nanolayer architecture (MoCx-N/CNL) using cheap cotton as carbon and nitrogen precursor and ammonium molybdate as Mo precursor. Transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy dispersive X-ray spectra (EDS), scanning electron microscopy (SEM), element mapping, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were utilized to characterize the as-prepared nanocomposites. The synergistic effect between dispersive Mo2C particles and N doping in MoCx-N/CNL leads to remarkable HER performance in acidic media. Different amount of Mo were doped in the samples by arranging the ammonium molybdate concentration. Three samples were obtained and MoCx-N/CNL-3 showed better HER electrocatalytic performance than other two samples. Moreover, the as prepared MoCx-N/CNL-3 exhibits excellent stability and durability in acidic media. A new viable route is provided to prepare molybdenum carbide embedded N-doped carbon hybrid architecture with higher HER stability and activity, it is of significance in novel HER catalyst preparation.

Enhancing coated paper mechanical properties via doping kaolin with ammonium molybdate

Mechanical properties of paper coating layers are very important in converting and printing operations. Kaolin is commonly used in paper coating as cheap pigment in addition to its superior properties. In this study, a new approach for improving coated paper mechanical properties using doped kaolin with ammonium molybdate was presented. Kaolin and modified kaolin were characterized using several analyses tools (e.g., XRD, SEM, and EDX), and then they were applied in paper coating mixture. The results revealed that the dopant was found in the kaolin as MoOx; this oxide form with its needle shapes led to change in the kaolin crystals, and its presence in high concentrations led to exfoliation of kaolin. Also, at high concentration it was found that MoOx reacted with γ-alumina that is found in kaolin after its heating at 300°C to form aluminum molybdate. It can be observed that modified kaolin increased the coated paper porosity and consequently the opacity; also bulk and thickness were increased. Significant improvement in coated paper tensile strength, bursting strength, tensile energy absorption, and bending stiffness was also noticed. Thermal study also showed that increasing the concentration of ammonium molybdate increased the heat stability of the coated paper.

Molybdate in Rhizobial Seed-Coat Formulations Improves the Production and Nodulation of Alfalfa.

Rhizobia-legume symbiosis is the most well researched biological nitrogen fixation system. Coating legume seeds with rhizobia is now a recognized practical measure for improving the production of legume corp. However, the efficacy of some commercial rhizobia inoculants cannot be guaranteed in China due to the low rate of live rhizobia in these products. A greenhouse experiment was conducted to assess the effects of different rhizobial inoculant formulations on alfalfa productivity and nitrogen fixation. Two rhizobia strains, (ACCC17631 and ACCC17676), that are effective partners with alfalfa variety Zhongmu No. 1 were assessed with different concentrations of ammonium molybdate in seed-coat formulations with two different coating adhesives. Our study showed that the growth, nodulation, and nitrogen fixation ability of the plants inoculated with the ACCC17631 rhizobial strain were greatest when the ammonium molybdate application was0.2% of the formulation. An ammonium molybdate concentration of 0.1% was most beneficial to the growth of the plants inoculated with the ACCC17676 rhizobial strain. The sodium carboxymethyl cellulose and sodium alginate, used as coating adhesives, did not have a significant effect on alfalfa biomass and nitrogen fixation. However, the addition of skimmed milk to the adhesive improved nitrogenase activity. These results demonstrate that a new rhizobial seed-coat formulation benefitted alfalfa nodulation and yield.

One-pot template-free synthesis of porous CdMoO4 microspheres and their enhanced photocatalytic activity

The optical and catalytic performances of materials strongly depend on their size, morphology, dimensionality and structure. Herein, we demonstrate a facile one-pot template free synthesis of hierarchical CdMoO4 porous microspheres via a simple low temperature oil bath method. The photoactivity of the as-prepared samples was evaluated by photocatalytic decolorization of Methyl Orange (MO) and Methylene Blue (MB) mixed dye aqueous solutions at ambient temperature under full solar spectrum. The results indicated that the concentration of ammonium molybdate and reaction time greatly influence the diameter, average crystallite size, specific surface area, pore structure and photocatalytic activity of the prepared samples. Especially, under the suitable conditions the prepared hierarchical CdMoO porous microspheres exhibited enhanced photocatalytic activity and high stability. Furthermore, it is found that the photocatalytic activity and formation rate of hydroxyl radicals greatly depend on the particle sizes and morphology of as-prepared samples. This work not only demonstrates a simple way to fabricate the hierarchical CdMoO4 porous microspheres but also shows a possibility for utilization of CdMoO4 porous microspheres for the photocatalytic treatment of waste water pollutants.

Ammonium molybdate added in hybrid films applied on tinplate: Effect of the concentration in the corrosion inhibition action

One of the ways to improve the anticorrosive properties of the hybrid films is with the addition of corrosion inhibitors based on inorganic salts. The protection mechanism involves the release of molybdate ions inserted in coatings by sol–gel during the immersion in the electrolyte, thereby minimizing the corrosion process. Siloxane–PMMA hybrid films are constituted by a silica network, to which the chains of poly (methyl methacrylate) (PMMA) are connected by covalent bonds (Class II) or by physical interactions (Class I). The stability and transparency enable the application of these materials in the coating of tinplate packagings in order to enhance corrosion resistance and reduce the brittleness of these products. In this context, the objective of this study is to coat the tinplate with a hybrid siloxane–PMMA (Class II) film obtained from a sol constituted of the alkoxide precursors: 3-(trimethoxysilylpropyl) methacrylate (TMSM), poly(methyl methacrylate) PMMA and tetraethoxysilane (TEOS), by varying the added corrosion inhibitor concentration from 0.01 to 0.02M. The films were obtained by a dip-coating process and characterized according to their morphological and electrochemical behavior. The results showed that hybrid films doped with corrosion inhibitors showed an increase in the layer thickness in comparison to the inhibitor-free film. Furthermore, the addition of a higher concentration of ammonium molybdate resulted in an increase of the corrosion performance of the hybrid films.

The electrocatalytic behavior of electrodeposited Ni-Mo-P alloy films towards ethanol electrooxidation

Ternary Ni–Mo–P thin films have been electrodeposited from citrate-based electrolyte onto graphite substrates for application as anode catalysts for ethanol electrooxidation. The operating deposition parameters were optimized to produce Ni–Mo–P alloy films of outstanding catalytic activity. The phase structure of the deposits was evaluated employing X-ray diffraction technique. Morphology and chemical composition of the deposited alloy films were studied using scanning electron microscopy and energy-dispersive X-ray analysis, respectively. The results demonstrated that the rate of Ni–Mo–P deposition increases with increasing the ammonium molybdate concentration in the plating electrolyte up to 10 g l−1. Also, the amount of Mo in the deposits increases with increasing the ammonium molybdate concentration up to 7.5 g l−1, and the maximum Mo content in the film was 9.1 at.%. The catalytic activity of Ni–Mo–P/C alloy films has been evaluated towards electrooxidation of ethanol in 1.0 M NaOH solution by using cyclic voltammetry and chronoamperometry. The catalytic performance of the prepared anodes as a function of the amount of Mo was studied. The results showed an increase in the oxidation peak current density of ethanol with increasing the Mo at.% in the deposited alloy films. Additionally, Ni–Mo–P/C electrodes displayed significantly improved catalytic activity and stability towards electrooxidation of ethanol compared with that of Ni–P/C electrode. Copyright © 2013 John Wiley & Sons, Ltd.

Molybdate and molybdate/permanganate conversion coatings on Mg–8.5Li alloy

A novel environment-friendly conversion coating for Mg–8.5Li alloy was obtained by immersing in a solution of molybdate. The concentration of ammonium molybdate and the addition of potassium permanganate were discussed in this experiment. The surface morphology of the conversion coatings was observed by scanning electron microscopy (SEM), and the chemical composition was investigated by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The corrosion resistance of Mg–8.5Li alloy and conversion coatings were investigated by means of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurement. The results showed that the coatings with cracked morphology were homogeneous and uniform. The conversion coatings were mainly composed of metal-oxide as detected by XPS. The results of electrochemical measurement and weight loss measurement revealed that the molybdate conversion coating had better corrosion resistance than bare alloy and chromate conversion coating, and the molybdate/permanganate conversion coating had lower corrosion current density and higher coating resistance than the molybdate conversion coating.

Effect of ammonium molybdate concentration on chemical mechanical polishing of glass substrate

The effect of the ammonium molybdate concentration on the material removal rate (MRR) and surface quality in the preliminary chemical mechanical polishing (CMP) of a rough glass substrate was investigated using a silica-based slurry. Experimental results reveal that the ammonium molybdate concentration has a strong influence on the CMP behaviors of glass substrates. When the ammonium molybdate was added to the baseline slurry, polishing rates increased, and then decreased with a transition at 2 wt.%, and the root mean square (RMS) roughness decreased with increasing ammonium molybdate concentration up to 2 wt.%, after which it increased linearly up to 4 wt.%. The improvement in MRR and RMS roughness may be attributed to the complexation of hydrolysis products of the glass substrate with the ammonium molybdate so as to prevent their redeposition onto the substrate surface. It was found that there exists an optimal ammonium molybdate concentration at 2 wt.% for obtaining the highest MRR and the lowest RMS roughness within a particular polishing time.

Shape tuning of ZnO with ammonium molybdate and their morphology-dependent photoluminescence properties

In this work, several nano/microscale structures of ZnO including nanospindles, microbundles, microrods, and nanoflowers have been prepared via a facile template and surfactant-free hydrothermal method mediated with ammonium molybdate. It is found that the morphology of ZnO could be readily tailored by simple variation of the concentration of ammonium molybdate. The effects of the concentration of ammonium molybdate and reaction temperature on the synthesis were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), and spectrofluorometer (FL) were used to characterize the products. Results reveal that the photoluminescence (PL) properties of the as-prepared ZnO are strongly dependent on their morphologies.

Preparation of Molybdic Acid Aggregates and Molybdenum Trioxide Powder with Controllable Size and Morphology

Molybdic acid aggregates were prepared by the reaction of ammonium molybdate with HNO_3 and HCl in a coexisting HAc or cetyl-trimethyl ammonium bromide (CTAB) solution,respec- tively.The results indicate that the size and morphology of as-prepared molybdic acid aggregates and annealed produets-α-MoO_3 powder were affected by the concentration of ammonium molybdate,HAc and CTAB.The molybdic acid aggregates with diameter of 1-2μm and length of several decades-micron can be obtained by the reaction of higher-concentration ammonium molybdate with HNO_3 in a coex- isting HAc or CTAB solution,repectively.After the as-prepared molybdic acid aggregates are annealed at 500-600℃for 3h,the nanometer-scaled lamellate and sub-micrometer MoO_3 powder are prepared. In addition,irregular molybdic acid aggregates rods are achieved by the reaction of lower-concentration ammonium molybdate with HCl in a coexisting CTAB solution.

Determination of arsenate by sorption pre-concentration on polystyrene beads packed in a microfluidic device with chemiluminescence detection

A highly sensitive chemiluminescence (CL) method for the determination of arsenate in water based on a simple microfluidic device was developed. The method was based on sorption pre-concentration of arsenate as a form of vanadomolybdoarsenate heteropoly acid (VMoAs-HPA) ion-paired with hexadecyltrimethylammonium bromide on the surface of polystyrene beads packed in a microfluidic device monitored by chemiluminescence detection. The composition of the VMoAs-HPA complex was studied by varying the concentrations of ammonium molybdate, ammonium vanadate and sulfuric acid with a variable-size simplex optimization process, of which the optimum concentrations were 6.3 x 10(-5), 5.0 x 10(-6) and 1.0 x 10(-2) M, respectively. In this work, 1.0 x 10(-3) M ethylenediaminetetraacetic acid was added to all work solutions to remove the interferences of the other metal ions on the CL detection. The integration of sorption pre-concentration not only increased the detection sensitivity but also eliminated the interference from phosphate and chromate. The calibration plot was linear from 1.0 x 10(-7) to 5.0 x 10(-5) M As(v). The limit of detection was 8.9 x 10(-8) M As(v) (S/N = 3). The time required for one analysis run was as short as 5 min. The relative standard deviation was 5.9% (n = 9). This method was successfully applied to the determination of arsenate in mineral-, drinking- and tap-water samples.

Synthesis and characterization of MoO 2/P(St- co-MMA- co-AA) microspheres via microemulsion by γ-ray radiation

MoO 2/P(St- co-MMA- co-AA) nanocomposite microspheres have been successfully synthesized in microemulsion system by γ-ray radiation at room temperature and under ambient pressure. The influence of experimental conditions on the formation of nanocomposites was discussed, such as the ratio of oil/water, monomers content and concentration of ammonium molybdate. The possible mechanism of nanocomposites was also proposed. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). From XRD patterns, it is can be seen that the product is amorphous and the pure monoclinic MoO 2 phase was gained by annealed at 400 °C in argon flow. TGA curve has only one big weight loss of polymer from 350 to 460 °C, hinting the formation of copolymer in the reaction. XPS spectra indicated that MoO 2 exists on the surface of nanocomposite microspheres. The catalytic property was investigated in the conversion of CO into CO 2, which showed about 80% conversion gained at 300 °C.

Hard anodic film on AI obtained by preimmersing in ammonium molybdate

The main purpose of this research is to obtain a hard anodic film on aluminium and to study the effects of molybdic oxyhydroxide films on the formation and properties of anodic films. The experiments begin by immersing the A1100 aluminium specimens in ammonium molybdate solution andthen anodising them in a 10 wt-% sulphuric acid solution by dc with 20 V at 20°C. Finally, the specimens are sealed in hot water at ~95°C. The study proves that a longer immersing time, a higher immersing temperature, a higher concentration of ammonium molybdate and a pH valueof 3 result in a harder anodic film. The molybdic oxyhydroxide film (the preimmersing process) retards the formation of the anodic film, producing a harder anodic film. The SEM images of the anodic film after the preimmersing process show that the pores of the film are closely and regularlydistributed. From the EDS analysis, molybdenum is detected in the anodic films. The preimmersing process decreases the anodic film thickness. However, the anodic film with preimmersing treatment has a maximum microhardness of 601 ± 10 HV(50 g), which is 62% higher than that withoutpreimmersing.

Cryo-negative staining

A procedure is presented for the preparation of thin layers of vitrified biological suspensions in the presence of ammonium molybdate, which we term cryo-negative staining. The direct blotting of sample plus stain solution on holey carbon supports produces thin aqueous films across the holes, which are routinely thiner than the aqueous film produced by conventional negative staining on a continuous carbon layer. Because of this, a higher than usual concentration of negative stain (ca. 16% rather than 2%) is required for cryo-negative staining in order to produce an optimal image contrast. The maintenance of the hydrated state, the absence of adsorption to a carbon film and associated sample flattening, together with reduced stain granularity, generates high contrast cryo-images of superior quality to conventional air-dry negative staining. Image features characteristic of unstained vitrified cryo-electron microscopic specimens are present, but with reverse contrast. Examples of cryo-negative staining of several particulate biological samples are shown, including bacteriophage T2, tobacco mosaic virus (TMV), bovine liver catalase crystals, tomato bushy stunt virus (TBSV), turnip yellow mosaic virus (TYMV), keyhole limpet hemocyanin (KLH) types 1 and 2, the 20S proteasome from moss and the E. coli chaperone GroEL. Densitometric quantitation of the mass-density of cryo-negatively stained bacteriophage T2 specimens before and after freeze-drying within the TEM indicates a water content of 30% in the vitreous specimen. Determination of the image resolution from cryo-negatively stained TMV rods and catalase crystals shows the presence of optical diffraction data to ca. 10A˚and 115A˚, respectively. For cryo-negatively stained vitrified catalase crystals, electron diffraction shows that atomic resolution is preserved (to better than 20 diffraction orders and less than 3A˚). The electron diffraction resolution is reduced to ca. 10A˚when catalase crystal specimens are prepared without freezing or when they are freeze-dried in the electron microscope. Thin vitrified films of TMV, TBSV and TYMV in the presence of 16% ammonium molybdate show a clear indication of two-dimensional (2-D) order, confirmed by single particle orientational analysis of TBSV and 2-D crystallographic analysis of TYMV. These observations are in accord with earlier claims that ammonium molybdate induces 2-D array and crystal formation from viruses and macromolecules during drying onto mica. Three-dimensional analysis of the TBSV sample using the tools of icosahedral reconstruction revealed that a significant fraction of the particles were distorted. A reconstruction from a subset of undistorted particles produced the characteristic T=3 dimer clustered structure of TBSV, although the spikes are shortened relative to the structure defined by X-ray crystallography. The 20S proteasome, GroEL, catalase, bacteriophage T2, TMV, TBSV and TYMV all show no indication of sample instability during cryo-negative staining. However, detectable dissociation of the KLH2 oligomers in the presence of the high concentration of ammonium molybdate conforms with existing knowledge on the molybdate-induced dissociation of this molecule. This indicates that the possibility of sample-stain interaction in solution, prior to vitrification, must always be carefully assessed.

Optimization of Conditions for Accurate Phosphonate and Total Phosphorus Assay on Lipid Samples, in Conjunction with Thin-Layer Chromatography

The range of inorganic acid normalities for maximum color formation of the phosphomolybdenum- blue complex (under heating) increases by elevating the ammonium molybdate concentration, and at a ratio of molybdate molarity/acid normality equal to 10, there is maximum color development at any acid normality in the range 1-4 ɴ with either HClO4 or H2SO4 (or their mixtures). On the basis of these features a revised method is described for the accurate determination of phosphonate-P percent of total-P. on lipid extracts and on TLC bands. The color at the final step, in both cases, is developed under the same conditions of molybdate, HClO4 and H2SO4 concentrations, thus avoiding possible errors produced by the use of two separate calibration curves.

ATPase and acid phosphatase activities associated with vacuoles isolated from storage roots of red beet (Beta vulgaris L.)

Phosphatase activities were measured in preparations of vacuoles isolated from storage roots of red beet (Beta vulgaris L.). The vacuoles possessed both acid phosphatase and ATPase activities which could be distinguished by their susceptibility to inhibition by low concentrations of ammonium molybdate [(NH4)6Mo7O24·4H2O]. The acid phosphatase was completely inhibited by 100 μM ammonium molybdate but the ATPase was unaffected. The acid phosphatase was a soluble enzyme which hydrolysed a large number of phosphate esters and had a pH optimum of 5.5. In contrast, the ATPase was partially membrane-bound, had a pH optimum of 8.0 and hydrolysed ATP preferentially, although it was also active agianst PPi, GTP and GDP. At pH 8.0 both the ATPase and PPase activities were Mg(2+)-dependent and were further stimulated by KCl. The ATPase and PPase activities at pH 8.0 may be different enzymes. The recovery and purification of the ATPase during vacuole isolation were determined. The results indicate that the Mg(2+)-dependent, KCl-stimulated ATPase activity is not exclusively associated with vacuoles.

活性炭による希薄水溶液中のモリブデンの処理

Molybdate in dilute aqueous solutions were treated by activated carbons. Unless otherwise stated, all the operations were carried out at 25°Cand initial concentration of ammonium molybdate and sodium molybdate were 5.0×10-3mol/l.The results in these experiments described as follows:1) Sorption of molybdate on the activated carbons varied considerably with the various types of the activated carbons. Residual molybdate in aqueous solutions reached a minimum values at pH 1.5-2.5 in the initial solution in case of any activated carbons.2) Sorption of molybdate on the activated carbons were little affected in the presence of large amount of copper ions, but they were inclined to decrease gradually with increasing ferric ions. Sorption of molybdate on the activated carbons were not affected very much even if SO42- as Na2 SO4 in the initial solution increased, within the range of molar ratio S042-/MO=about 50.3) Molybdate sorbed on the activated carbons could be eluded by alterations in pH of the solutions. lkaline solutions (NH4OH, NaOH etc) were more effective eluents for desorption of molybdate than acidic solutions (H2S04, HC1 etc).