Ammonium Molybdate Research Articles

Paradoxical Effect of Combined Exposure of Semax and Ammonium Molybdate on Learning and Memory of Rats

The combined effect of semax with aqueous solutions of lead diacetate (10-7 M) and ammonium molybdate (10-5 M) on the formation of a conditional two-way avoidance reaction in rats in a shuttle chamber was studied. It was found that both heavy metal salts inhibit learning and memory; lead diacetate caused greater depression. Semax slowed down the production of the conditional reaction, but counteracted the negative influence of both metals on this process. At the same time, the influence of semax on the formation of the avoidance reaction in the presence of ammonium molybdate, which in itself inhibited avoidance, paradoxically intensified. With the combined effect of the peptide and ammonium molybdate, the formation of a conditional reaction occurred much faster than against the background of semax without combination with molybdenum. In general, the data obtained indicate that semax counteracts the neurotoxic effect of lead and molybdenum salts. Since the main mechanism of the neurotoxic effect of heavy metals is oxidative stress, the indicated positive effect of semax can, in our opinion, serve as confirmation of the presence of antioxidant properties in the spectrum of pharmacological activity of the peptide.

OIL CONTENT IN WINTER RAPE SEEDS DEPENDING ON MICRONUTRIENT NUTRITION

The article is devoted to the study of the role of micronutrients in their application in the form of foliar fertilization in view of their influence on the quality indicators of the formed crop, in particular on the oil content of seeds as a basic indicator that determines the value of winter rape as a crop for multipurpose use. The effectiveness of monocomponent application of the main physiologically active microelements in two phenological critical phases of growth and flowering of winter rape plants with different dominance of growth and growth-reproductive processes of plant organism differentiation - in the phenological phases of stemming and flowering - was investigated. The effectiveness of the influence of single-component microelements selected by the typological composition of modern multicomponent chelated microfertilizers in the form of sulfate salts, boric acid and ammonium sulfate at a physiological concentration of 0.2 %, taking into account the regulation of concentrations of physiologically active agrochemicals in the format of foliar feeding with aqueous salt solutions, was determined. It was found that the use of each of the studied microelements was effective and significant in terms of increasing the oil content of seeds in comparison with the control variant of water treatment. Individual peculiarities of seed oil content formation for two high-intensity varieties of winter rape for each of the studied microelements were established both from the standpoint of the increase in oil content to the control and from the standpoint of assessing the variability of its value, taking into account the two-year cycle of study and variation within the general set of the obtained accounting values within the replications of the experiment. On the basis of the data obtained, the expediency of the timing of foliar fertilization with microfertilizers of winter rape hybrids was determined and the role of the genotypic component in the effectiveness of the use of corrective foliar fertilization with various microelements was noted. It was established on the basis of a two-year research cycle for a guaranteed increase of oil content in seeds of intensive winter rape hybrids by at least 0.6-1, 8 % under the condition of one-component use of trace elements in the form of foliar feeding, they should be used in the following order of increasing expediency and validity of Co>Zn>B>Cu>Mn>Mo in the form of a solution of salt sulfates, boric acid and ammonium molybdate at 0.2 % concentration of the working solution for foliar feeding. Prospects for further research in the field of optimization of fertilization of intensive hybrids of winter rape with microfertilizers are formulated.

Improved Supercapacitor Performance with Enhanced Interlayer Spacing of Nanoflower MoS2 in Long Discharge Time in LED‐Glowing Application

The 2D materials have seen recent significant development in terms of material features with superior electrochemical capability. This urges for extensive research as potential aspirants for energystorage applications. Herein, the synthesis of MoS2 nanostructures with molar ratio 1:30 (nanosheets) and 1:15 (nanoflower) of ammonium molybdate tetrahydrate and thiourea single‐steps hydrothermal methods through different reaction times and observed enhanced interlayer spacing is reported. Field emission scanning electron microscopy analysis reveals that synthesized MoS2 nanostructure has 3D flower‐like and ultrathin 2D sheet‐like morphologies. The enhanced interlayer spacing in nanoflower over nanosheet is confirmed through high‐resolution transmission electron microscopy. The X‐ray diffraction and Raman studies reveal the hexagonal crystalline phase of MoS2 (2H‐MoS2). Surface functional groups present are studied by Fourier transform infrared. Through X‐ray photoelectron spectroscopy, the chemical composition with its binding energy of prepared MoS2 is observed. Specific surface area and pore‐size distribution of both 2H‐MoS2 nanosheets and nanoflower are examined by Brunauer–Emmett–Teller and Barrett–Joyner–Halenda analysis. Owing to these excellent physicochemical properties, nanoflower also exhibits energy‐storage device capability. MoS2 nanoflower demonstrates high specific capacitance and cyclic stability in three‐electrode systems. A practical approach is investigated to test the practical application of enhanced interlayer spacing by studying the time of charge and discharge of light‐emitting diode.

SPECTROPHOTOMETRIC DETERMINATION OF THE TANNIDITY OF LIGNOSULFONATES IN THE PRODUCTION OF REAGENT SYSTEMS FOR OILFIELD CHEMISTRY

The article is devoted to the issue of quantitative determination of the main qualitative indicator of lignosulfonates - a product of processing of vegetable wood raw materials. For a number of reasons of various nature, the quality of lignosulfonates has declined sharply over the past decades. The consequence was the need for additional operations to modify the lignosulfonate matrix in the technological cycles of obtaining reagent systems for oilfield chemistry, in the case of supplies of lignosulfonate with a low tannidity index. The tannidity index characterizes the inhibitory or tanning ability of reagent systems based on lignosulfonate and is quantitatively determined by the content of OH-phenolic functional groups in the composition of the lignosulfonate macromolecule (20-30 monomer units). The paper presents a comparative study of the results of determining the tannidity index of lignosulfonates of various methods of obtaining by adsorption on collagen and spectrophotometric method with ammonium molybdate. The results of the determinations were processed by the method of mathematical statistics and it was found that the variances of the results of experimental studies are homogeneous and belong to one general population according to the Fisher criterion. Based on the results of the work carried out, it can be considered mathematically justified to replace the long-term collagen method with a spectrophotometric express method for determining tannidity with ammonium molybdate at a wavelength of 400 nm and calculating the quantitative content of OH-phenolic groups. The determination of the values of the confidence intervals of the analytical methods under study shows a relatively high accuracy of the spectrophotometric method compared to the collagen method, which is characterized by overestimated results. Recommendations were issued on the inclusion of a spectrophotometric method for determining the tannidity of the process of obtaining reagent systems as an input control operation of raw materials. For citation: Teptereva G.A., Rolnik L.Z., Pugachev N.V., Zhuravleva A.A., Lukmanova I.F. Spectrophotometric determination of the tannidity of lignosulfonates in the production of reagent systems for oilfield chemistry. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 6. P. 23-30. DOI: 10.6060/ivkkt.20236606.6797.

A novel membrane-integrated sustainable technology for downstream recovery of molybdenum from industrial wastewater

An experimental investigation was conducted to recover and recycle a precious metal (molybdenum) while treating industrial wastewater using a novel membrane-integrated hybrid technology. Hollow-fiber crossflow modules containing ultrafiltration and nanofiltration membranes in the recirculation mode successfully separated 96.5% of the molybdenum from industrial wastewater. The volume of feed wastewater (250 L) was reduced by ∼94%, and the molybdenum concentration was increased from 1.32 to 10.2 g/L using a VNF-1 membrane for its smooth recovery (98.7%) as ammonium molybdate by chemical precipitation under response-surface-optimized conditions of critical parameters of NH4+/Mo ratio (1.32), pH (1.7), temperature (62 °C), and time (15.7 h). Further, ammonium molybdate was converted into MoO3 of high purity (99.4%) using thermal decomposition at 500 °C for 30 min. This is the first proof-of-concept demonstrating the use of a membrane system to recover molybdenum from industrial wastewater to promote a circular economy for recycling and regenerating valuable resources.

Mo and N co-doped iron biochar materials activating peroxymonosulfate for enhanced degradation of bisphenol A: Mechanism discussion and practical application

Mo and N co-doped iron biochar material (Fe/Mox-NC) was prepared through one-pot calcination method with anhydrous iron chloride, ammonium molybdate, and cherry stone powder as precursors. The composite can effectively catalyze activation of peroxymonosulfate (PMS) for organic pollutants degradation, and the removal rate of 20 mg/L bisphenol A (BPA) reaches 99.08% in 30 min in the presence of 0.1 g/L Fe/Mo0.1-NC and 1 g/L PMS. Electrochemical analysis indicates that appropriate doped Mo and N can improve the electron transfer performance of the composite, which enhances the PMS activation property for BPA degradation. Quenching experiments and electron paramagnetic resonance analysis both demonstrated that the Fe/Mo0.1-NC/PMS system generated SO4•−, •OH and 1O2, which involved in BPA degradation. Moreover, a galvanic oxidation process had shown that there existed nonradical pathway which relied on electron transfer. The degradation pathway is proposed by measuring the intermediate products with HPLC-HRMS/MS. Through the exploration of the reaction mechanism, low-valence molybdenum ions can promote the cycle of Fe2+/Fe3+, and the pyridine-N and graphitic-N contained in Fe/Mo0.1-NC can catalyze activation of PMS together with Fe2+. The designed membrane filtration device revealed the feasibility of the composite in dynamic process, which was great significant for actual operation of water treatment. Furthermore, the Fe/Mo0.1-NC/PMS system could effectively decompose organic pollutants in the effluent from sewage treatment plant, achieving 82.6% of total organic carbon removal rate. This study not only prepared a novel heteroatom doped Fe-biochar material for PMS activation to degrade organic pollutants, but also deepened the reaction mechanism and explored its applicability for advanced treatment of real wastewater.

Mechanism and kinetics of decomposition reaction of ultrafine ammonium molybdate for preparing ultrafine MoO3 powder

The decomposition reaction of ammonium molybdate to prepare molybdenum trioxide (MoO3) is a crucial step for the production of molybdenum powder. In this study, ultrafine MoO3 was prepared by calcining ultrafine ammonium molybdate in air atmosphere. The decomposition of ultrafine ammonium molybdate to generate MoO3 was proved to be a single-step reaction without intermediates in air atmosphere. Furthermore, the effects of temperature and reaction time on the phase composition, morphology and particle size distribution of products were also studied. The results showed that the temperature (in the range of 350 °C–450 °C) had a significant influence on the reaction rate, and the time required for completing the decomposition reaction was shortened as the temperature increased. However, the particle size of produced MoO3 was almost unchanged. It was also found that the phase compositions of products at different material layers (up, middle and bottom layers) were different, because the mass transfer of gaseous product in material layers affected the decomposition reaction. Additionally, a kinetic model considering the mass transfer of gaseous product in the material layer as well as the interface chemical reaction was proposed. Application of the developed model validated that the model could well describe the decomposition kinetics of ultrafine ammonium molybdate.

Highly Sensitive Colorimetric Detection of Histidine Using Histidyl-tRNA Synthetase as the Bioreceptor

This study investigated the enzymatic detection of histidine among the 20 amino acids using histidyl-tRNA synthetase (HisRS) as the histidine recognition element. Previously, we studied the binding ability of HisRS and used it as the recognition element in a biosensor; however, in this study, we focused on improving the sensitivity and expanding the dynamic range of histidine analysis using HisRS, as well as analyzing the histidine concentration in real food samples for practical application. Previous studies, as well as our own, have indicated that the binding of HisRS, is strongly affected by the concentrations of 5′-triphosphate (ATP) and magnesium chloride (MgCl2) in the HisRS reaction buffer. Ammonium molybdate or Trinder’s reagent was used for the coloring reaction. Upon optimization of the reaction conditions, we found that 40 mM ATP and 50 mM MgCl2 yielded a linear relationship from 1 to 150 μM histidine (correlation coefficient: r = 0.960). Compared to our previous methods, this method detected histidine over a wider range and with higher sensitivity. Moreover, in real food samples, the plots of spiked histidine were in good agreement with the histidine calibration curve, with a measurement error range of within ± 4.9%.

The Growth Process and Photocatalytic Properties of h-MoO3 and α-MoO3 under Different Conditions

In this experiment, we investigated the effects of different reactions on the growth process and morphology of h-MoO3 and α-MoO3, and their optical properties and photocatalytic activities were also investigated. Orthogonal experiments were designed to investigate the effects of four influencing factors, namely the amount of ammonium molybdate tetrahydrate (AHM), the type of acid, the reaction temperature and the holding time, on the morphology of h-MoO3 by a microwave hydrothermal method. The phase and morphology were analyzed by using advanced physicochemical techniques. The XRD results showed that the samples produced by the microwave hydrothermal method had sharp diffraction peaks, high crystallinity and complete crystalline shape. AHM generates h-MoO3 in both hydrochloric and nitric acid environments. In particular, when the temperature rises to 200 °C, the generated h-MoO3 will be converted to α-MoO3 in a nitric acid environment, which will be generated in a sulfuric acid environment. Therefore, increasing the reaction temperature will result in the conversion of h-MoO3 to α-MoO3 in sulfuric acid solution. SEM results show that the sample prepared from hydrochloric acid solution has a complete hexagonal prism morphology, while the sample prepared from sulfuric acid solution presents a long fibrous morphology, and the sample prepared from nitric acid solution has many defects on the surface of the hexagonal prism morphology. Interestingly, sample A11 prepared in nitric acid solution showed a spherical structure. Since the generated A3, A6 and A9 samples are all stable phase α-MoO3, they have a wider band gap compared with other samples. Their particle size is up to the nanometer scale, so they have strong adsorption properties. The spherical sample A11 has excellent adsorption and photocatalytic activity.

Spectrophotometric Determination of Phosphates in Detergent Samples Available in Tansen, Palpa

Phosphate is primarily used as a builder in detergents, which helps soften hard water, thereby increasing the cleansing power of detergents. Extensive discharge of phosphate from detergents leads to eutrophication of surface water bodies. This work aims to assess the amount of phosphate present in detergent samples available in Tansen, Palpa, and compare its concentration between local and foreign detergents. Phosphate in detergent samples can be determined by the molybdenum blue phosphorus method using a spectrophotometer. The experimental process relies on forming a phosphomolybdate blue complex with ammonium molybdate and the subsequent reduction of the complex by hydrazine hydrate in an aqueous sulphuric acid medium. The system obeys Beer-Lambert’s law at 830 nm in the concentration range of 2-16 ppm. In this study, the phosphate concentration in local detergents (Dhoni, Light, V-Series, Nirma, Upahar, Patanjali, Rin Shakti and Dr Jhatka) varied from 15.54-33.03 ppm, and that of foreign detergents (Wheel, Super Check, Surf Excel, Tide and Ariel) ranged from 23.81- 32.65 ppm. The amount of phosphate was compared between local and foreign detergent samples using the student's t-test, which revealed no significant difference between them. The results obtained from the study disclosed that the detergents under investigation are within the permissible limits of phosphate. However, non- phosphate-based builders can be used to discourage the use of phosphate in detergents.

Facile preparation and high microwave absorption of flower-like carbon nanosheet aggregations embedded with ultrafine Mo2C

Rational regulation of microstructure and components is vital for excellent microwave absorption performance. In this study, we report flower-like carbon nanosheet architectures embedded with ultrafine Mo2C as a microwave absorber, prepared via simple carbothermal reduction using Mo-polydopamine as the precursor. We found that the particle size of the obtained Mo2C/C composites could be simply tailored by the added ammonium molybdate content in the initial solution for the preparation of the Mo-polydopamine precursor. This helped tailor the BET surface area, which significantly impacts microwave absorption performance. The sample with a BET surface area of 173.31 m2g−1 displayed high-efficiency microwave absorption, and the effective absorbing band reached up to 7.04 GHz (10.96–18 GHz) with the matching thickness of 2.9 mm at relatively low filler loading (only 10 wt%). Thus, the excellent microwave absorption performance and simple preparation process of the flower-like Mo2C@C composites are promising for applications requiring lightweight and broadband microwave absorption.

The research of the effect of the interaction of molybdenum, cobalt, piracetam and ascorbic acid on cognitive processes in rats

The problem of combined effects on animals of a combination of drugs with heavy metals (HM) is considered. The study was carried out at the K.L.Khetagurov North Ossetian State University (Vladikavkaz, RSO-Alania) and the Lomonosov Moscow State University (Moscow). The effect of lead diacetate and ammonium molybdate on the training of rats was studied separately, as well as in combination with ascorbic acid and piracetam. It has been found that lead and molybdenum salts inhibit avoidance reactions and inter-signal reactions. The combined effect of these salts with ascorbic acid and piracetam led to mixed results. The nootrope counteracted the inhibition of avoidance reactions by metals, but increased the inhibition of inter-signal reactions, which serve as an important characteristic of learning. In contrast, ascorbic acid reduced the inhibition of both avoidance reactions and inter-signal reactions caused by HM. The use of 2 drugs with HM led not only to an increase in the positive effect exerted by each of the drugs on training, but also to its weakening. The results obtained indicate that the interaction of drugs and HM, taking place in real conditions, is fraught with unpredictable consequences and may pose a danger to human and animal health. This justifies the need for further analysis of the combined effects of several drugs with HM.

Release mechanism of impurity potassium in molybdenum concentrate treatment process

AbstractThe kinetic characteristics and mechanism of potassium release in the molybdenum concentrate treatment process were studied by kinetic analysis and analytical techniques such as SEM−EDS, MLA and ICP. The results show that the first-order kinetic model is the best kinetic model of potassium release in the water washing and ammonia leaching process. Potassium is present in molybdenum concentrate in the form of soluble potassium ions and four potassium minerals. During the roasting process of molybdenum concentrate, some muscovite decomposed into orthoclase, while other muscovite combined with impurity metal elements to form anandite. Furthermore, the transformation of muscovite to orthoclase could be effectively inhibited by the rapid cooling of molybdenum calcine. The results could provide a basis for reducing potassium content in ammonium molybdate products.

Construction of Co-NC@Mo2C hetero-interfaces for improving the performance of Li-O2 batteries

Lithium-oxygen batteries (LOBs) are becoming the rising stars of a new generation of energy storage devices due to high theoretical energy density. The crucial factor of its high performance and stability is developing efficient cathode electro-catalysts. In this work, the Zn3[Co (CN)6]2 Prussian Blue analog (Zn-CoPBA) was used as the precursor, then ammonium molybdate tetrahydrate was incorporated by hydrothermal treatment, and finally Mo2C-modified Co-NC was prepared by one-step pyrolysis. The mesoporous hetero-interfaces of N-doped carbon matrix embedded by Mo2C/Co nano-heterostructures facilitate the transport of substances, provide more catalytic active sites and storage space for the discharge product Li2O2 due to the characteristic electronic structure and catalytic properties of Mo2C with d-orbital state distribution near the noble metal-like Fermi level. The composite Co-NC@Mo2C was used for LOBs cathode catalyst, it presents wonderful charge-discharge specific capacities (21,930 mA h g − 1), stable cycling performance.

Elimination of the Interfacial Crud in the Extraction of Simulated High-Level Liquid Waste After Denitration in the TRPO Process

ABSTRACT Denitration is a proven technique that can reduce the nitric acid concentration of high-level liquid waste (HLLW) to meet the aqueous acidity requirement of the TRPO (TriAlkyl Phosphine Oxide) process. However, interfacial crud is generated in the TRPO extraction of the HLLW after denitration. In this work, the interfacial crud was characterized by Fourier-transform infrared spectroscopy and dynamic light scattering. The extraction distribution ratio of zirconium by 30% TRPO in kerosene decreases dramatically after the simulated HLLW is denitrated, and we proposed that the presence of zirconium in the simulated HLLW after denitration is responsible for the generation of interfacial crud. Using ammonium molybdate as a precipitant, the concentration of zirconium in the simulated HLLW was successfully reduced without essentially changing the concentration of other metal ions. The effects of reaction time, temperature, and amount of ammonium molybdate added on the zirconium removal process were investigated and the precipitates formed in the removal of zirconium were characterized by scanning electron microscope, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Finally, after reducing the concentration of zirconium in the simulated HLLW to below 10 mg/L by using ammonium molybdate, the extraction experiment was performed again and no interfacial crud was observed.

Effects of heat exposure and vitamin C intervention on oxidative stress and blood pressure changes in treadmill rats

Objective: To investigate the effect of oxidative stress caused by heat exposure on the blood pressure increase of treadmill rats and the intervention of antioxidants. Methods: In June 2021, Twenty-four healthy SD male rats were randomly divided into four groups: normal temperature feeding, normal temperature treadmill, high temperature treadmill and high temperature treadmill supplementation with vitamin C groups, 6 rats in each group. The rats run on the platform in normal temperature or heat exposure environment for 30 min in the morning and in the afternoon daily, 6 days per week. The daily vitamin C supplement dose of high temperature treadmill supplementation with vitamin C group was 10 mg/kg. BP recordings were done at the end of the week. The rat vascular lipofuscin (LF) was detected by ELISA, the rat serum nitric oxide (NO) was detected by nitrate reductase method, the serum malondialdehyde (MDA) was detected by thibabituric acid method, the serum glutathione peroxidase (GPx) and superoxide dismutase (SOD) were detected by chemiluminescence method, and the serum catalase (CAT) was detected by ammonium molybdate method. The total antioxidant capacity (T-AOC) of serum was measured by iron reduction/antioxidant capacity method, and the content of nuclear erythroid 2-related factor 2 (Nrf2) in vascular tissue was measured by Western blot. The intra-group mean was compared by repeated measurement analysis of variance, and the inter-group mean was compared by single-factor analysis of variance and post-event LSD-t test. Results: Compared with the previous time point, the systolic BP and diastolic BP of the high temperature treadmill group were significantly increased at 7, 14 and 21 d, and decreased at 28 d which were higher than the initial level (P<0.05), and the systolic BP and diastolic BP values at each experimental time point were significantly higher than those of normal temperature treadmill group (P<0.001). The changes of thickening of the artery wall, no smoothing of the endodermis and irregular arrangement of muscle cells in high temperature treadmill group were observed. Compared with the normal temperature treadmill group, the content of MDA in serum, and LF in vascular tissue were significantly increased, the activities of SOD, CAT, T-AOC, the content of NO in serum, and the expression of Nrf2 in vascular tissue were significantly decreased in high temperature treadmill group (P<0.05). Compared with the high temperature treadmill group, the systolic BP and diastolic BP values at 7, 14, 21 and 28 d, the content of serum MDA and LF in vascular tissue were significantly decreased, the activities of CAT and T-AOC, and the expression of Nrf2 in vascular tissue significantly increased (P<0.05), the histopathological changes of the artery wall improved in high temperature treadmill supplementation with vitamin C group. Conclusion: Heat exposure has effect on oxidative stress, which may be related to the increase of BP. Vitamin C as an anti-oxidative enhancer can prevent those negative effects, which could alleviate the pathological changes of vessel intima in heat-exposed rats. And the Nrf2 may be a regulated factor to vascular protection.

Rapid Synthesis of C60-MoC Nanocomposites by Molten Salt Electrolysis for Hydrogen Evolution

Molybdenum carbide is a promising alternative of Pt/C in H2 evolution reaction (HER). However, its synthesis is time-consuming and energy-intensive. In this work, we propose a rapid one-pot strategy to fabricate C60-MoC nanocomposites in Li2CO3-K2CO3 molten salt using CO2 and ammonium molybdate as carbon and Mo sources, respectively. The as-obtained C60-MoC-600 sample at 600 °C shows high HER activity in both acid and alkaline electrolytes. Especially in 1 M KOH, the η 10 (overpotential at 10 mA cm−2) of C60-MoC-600 is 142 mV. Under an industrial current density of 220 mA cm−2, its activity with an overpotential of 250 mV is close to that of commercial Pt/C and exhibits excellent constant current stability during 10 h. This strategy not only implements the simple synthesis of MoC-based catalysts but also paves a highly efficient way for the rapid abatement and high-value-added utilization of CO2.

In situ highly dispersed loading of molybdenum dioxide with oxygen vacancies on N-doped graphene for enhanced oxidative desulfurization of fuel oil

Herein, molybdenum dioxide (MoO2) nanoparticles with a particle size of 1.78 nm was uniformly anchored on nitrogen-doped reduced graphene oxide (NrGO) with strong electron-donating effect by in situ annealing of the precursor composed of polyaniline-modified graphene oxide (PANI/GO) and ammonium molybdate. The as-prepared MoO2/NrGO catalyst at 800 °C showed the excellent oxidative desulfurization (ODS) activity and reusability. In the presence of H2O2, the DBT removal over MoO2/NrGO-800 could reach 99.8 % within 10 min at 60 °C, and it was almost still retained even after 8 cycles. The outstanding ODS performance is importantly ascribed to the following aspects. The electron transfer from electron-rich NrGO to MoO2 could not only weaken Mo-O bonds and improve the small size and dispersion of MoO2, resulting in more oxygen vacancies and exposed active sites, but also reduce the leaching of active sites due to the induced electronstatic interaction. Oxygen vacancies intrinsiclly facilitate the generation of active oxygen intermediates. Radical scavenger experiments and electron paramagnetic resonance (EPR) revealed that during the DBT oxidation over MoO2/NrGO-800, •OH radicals are the major active species, and electron transfer is still an important step.

Modifying of calcareous soil with some acidifying materials and its effect on Helianthus annuus (L.) growth

Calcareous soils contain a high concentration of calcium carbonate (CaCO3), which influences soil properties related to plant growth. Humic acid (HA) and ammonium molybdate (AM) were added as treatments for calcareous soils at concentrations of 0.1, 0.5 and 1 g/l respectively. The pots were divided into three groups. The first set of groups were irrigated with AM, while the second set of groups were irrigated with HA. As a control, the third group was irrigated using only tap water. Many soil properties and plant characteristics were measured during the experiment. The results showed that most of the studied treatments aided to increase organic carbon of calcareous soil and improved sunflower height, leaf area and shoot and root biomass. All investigated treatments significantly enhanced carbohydrates content in the sunflower shoots, except the treatment with 0.1 g/l AM, while only the with AM (under all studied concentrations) significantly enhanced carbohydrates content in roots higher than untreated. Proteins content in the shoots and roots of sunflower significantly increased when treated only with 1 g/l HA higher than control. The amino acid content of sunflower roots enhanced when treated with 0.1 and 1 m/l HA and 0.5 g/l AM Evidently, acidifying materials enhanced the calcareous soil and increased productivity.

Influence of polycrystalline MoS2 nanoflowers on mouse breast cancer cell proliferation via molten salt sintering

In this paper, polycrystalline molybdenum disulfide (MoS2) nanoflowers were prepared by mixing ammonium molybdate tetrahydrate [(NH4)6Mo7O24·4H2O] and potassium thiocyanate (KSCN) at 300 °C for 2 h via molten salt sintering method. Under scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM), MoS2 showed popcorn-like shape, which surface distribution defects were easy to be further modified. MoS2 as a nano-enzyme was used to inhibit the proliferation of mouse breast cancer cells (4 T1), which had 69.8 % inhibitory effect on 4 T1 cell proliferation. Electron spin resonance (ESR) analysis showed that MoS2 could produce a large number of stable hydroxyl radicals (–OH). The disulfide bond in MoS2 was highly sensitive to reactive oxygen species (ROS). High ROS level leads to the death of cancer cells under oxidative stress and inhibits the proliferation of 4 T1. This work demonstrates that MoS2 is a potential anticancer drug or carrier for cancer treatment.