Preliminary study on preparation of ammonium metatungstate from ammonium tungstate solutions using bipolar membrane electrodialysis

Guan, Wenjuan; Zeng, Li; Zhang, Guiqing; Zeng, Chengwei; Shang, Guanghao; Wang, Dezhi

doi:10.1016/j.hydromet.2017.01.013

Cited by 12 publications

(4 citation statements)

References 3 publications

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“…The reason may be that the higher solubility of ammonium metatungstate in water than ammonium tungstate. [36][37][38] This result also confirms the importance of selecting a proper tungsten source and controlling the microstructure of the photoelectrodes for improving the final PEC performance. Scanning electron microscope (SEM) observation of the resultant CuWO 4 films shows that both the CuWO 4 -AM and CuWO 4 -AT films are composed of irregular nanoparticles (Figures 2c-2d).…”

Section: Resultssupporting

confidence: 60%

Ultrasonic Spray Pyrolysis‐assisted Fabrication of Ultrathin CuWO₄ Films with Improved Photoelectrochemical Performance

Duan

Nahrawy

et al. 2021

ChemNanoMat

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CuWO 4 is a promising n-type oxide semiconductor for photoelectrochemical (PEC) applications due to the suitable band gap and good photochemical stability. An easy and large-scale fabrication of ultrathin CuWO 4 films with improved PEC performance is highly desired for future practical application but still challenging. Considering that the ultrasonic spray pyrolysis approach is a low-cost and scalable technique for fabricating films with controllable thickness, we here report the controllable fabrication of ultrathin CuWO 4 films with improved PEC performance by an automatic ultrasonic spray pyrolysis method. The effects of different tungsten sources and film thickness on the PEC performance of the resultant CuWO 4 film were studied in detail. We find that the ultrathin CuWO 4 film prepared from the ammonium metatungstate with a thickness of 2.16 μm shows the best PEC performance of 41 μA cm À 2 at 1.23 V vs.RHE for water oxidation under visible light irradiation. We also explored the different charge transfer mechanism and PEC performance of the resultant CuWO 4 films under back and front illumination.

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Section: Resultssupporting

confidence: 60%

Ultrasonic Spray Pyrolysis‐assisted Fabrication of Ultrathin CuWO₄ Films with Improved Photoelectrochemical Performance

Duan

Nahrawy

et al. 2021

ChemNanoMat

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“…This was mainly related to the increase of the conductivity of the acid/base compartment caused by the splitting of water molecules and the migration of the hydrate ions, reducing the electrical resistance of the stack. Subsequently, the BMED stack reached a stable state in the intermediate phase for a while, presenting a slight change in the stack voltage, which suggested that the stack resistance remained almost constant in this stage [14]. In the period, the increase of the resistance in the salt compartment, resulting from the continuous decrease of the mixture of Na 2 SO 4 and (NH 4 ) 2 SO 4 solutions, was counteracted by the reduction of the resistance of the acid and base compartments, since the increase of the H 2 SO 4 and NaOH concentrations [15].…”

Section: Effects Of Current Densitymentioning

confidence: 99%

The Novel Strategy for Increasing the Efficiency and Yield of the Bipolar Membrane Electrodialysis by the Double Conjugate Salts Stress

et al. 2020

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To improve sulfuric acid recovery from sodium sulfate wastewater, a lab-scale bipolar membrane electrodialysis (BMED) process was used for the treatment of simulated sodium sulfate wastewater. In order to increase the concentration of sulfuric acid (H2SO4) generated during the process, a certain concentration of ammonium sulfate solution was added into the feed compartment. To study the influencing factors of sulfuric acid yield, we prepared different concentrations of ammonium sulfate solution, different feed solution volumes, and different membrane configurations in this experiment. As it can be seen from the results, when adding 8% (NH4)2SO4 into 15% Na2SO4 under the experimental conditions where the current density was 50 mA/cm2, the concentration of H2SO4 increased from 0.89 to 1.215 mol/L, and the current efficiency and energy consumption could be up to 60.12% and 2.59 kWh/kg, respectively. Furthermore, with the increase of the volume of the feed compartment, the concentration of H2SO4 also increased. At the same time, the configuration also affects the final concentration of the sulfuric acid; in the BP-A-C-BP (“BP” means bipolar membrane, “A” means anion exchange membrane, and “C” means cation exchange membrane; “BP-A-C-BP” means that two bipolar membranes, an anion exchange membrane, and a cation exchange membrane are alternately arranged to form a repeating unit of the membrane stack) configuration, a higher H2SO4 concentration was generated and less energy was consumed. The results show that the addition of the double conjugate salt is an effective method to increase the concentration of acid produced in the BMED process.

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“…Driven by direct current across the membrane stack, the water molecules in the intermediate layer of the bipolar membrane (BP) are dissociated into OH – and H + . Combined with anion-exchange membranes and cation-exchange membranes, the BMED system can convert salts in situ into corresponding acids and bases production. , Hence, the BMED technique has a wide range of applications in the fields of chemical industry, food processing, hypersaline wastewater treatment, resource recovery, and fermentation engineering. − The BMED technology has also been used to produce inorganic acids and bases from salts, such as Na 3 PO 4 , NaCl, NH 4 Cl, NaNO 3 , NaBr, and Na 2 SO 4 . , In addition to producing inorganic bases and acids, the BMED technique has been applied for the production of organic acids, such as nicotinic acid, succinic acid, and sebacic acid or α-ketoglutaric acid . As mentioned above, the feasibility of the BMED technique for inorganic acid production has been proven, with acceptable unit energy consumptions and current efficiencies.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Hypophosphorous Acid by Bipolar Membrane Electrodialysis: Process Optimization and Phosphorous Acid Minimization

Yan

Hang

Liu

et al. 2019

Ind. Eng. Chem. Res.

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Hypophosphorous acid (H3PO2) is an important chemical product with wide applications in pharmaceuticals and electroless plating. In this study, bipolar membrane electrodialysis (BMED) was used to produce H3PO2 from sodium hypophosphite salt (NaH2PO2) to replace the traditional preparation methods. The BMED process was optimized in terms of current density, NaH2PO2 salt concentration, and initial NaOH concentration of the base solution. The results indicated that low Na+ leakage occurred at lower salt concentrations. Under the optimum conditions, such a BMED system obtained a high concentration of H3PO2, a low Na+ content, and a low energy consumption, equaling to 1.03 mol/L, 670 ppm, and 1.18 kW h/kg, respectively. To minimize the amount of phosphorous acid (H3PO3) generated from H3PO2 oxidation during the BMED process, a nitrogen aeration operation was applied in both the acid and salt chambers, decreasing the HPO3 2– content to 251 ppm, which was 44.1% lower than that without a dissolved oxygen content control strategy. The newly produced H3PO3 during the BMED process was reduced by 96.5%. The obtained results indicated that the BMED process has great potential for application in the production of high-quality H3PO2 from NaH2PO2 in industry.

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Preliminary study on preparation of ammonium metatungstate from ammonium tungstate solutions using bipolar membrane electrodialysis

Cited by 12 publications

References 3 publications

Ultrasonic Spray Pyrolysis‐assisted Fabrication of Ultrathin CuWO₄ Films with Improved Photoelectrochemical Performance

Ultrasonic Spray Pyrolysis‐assisted Fabrication of Ultrathin CuWO₄ Films with Improved Photoelectrochemical Performance

The Novel Strategy for Increasing the Efficiency and Yield of the Bipolar Membrane Electrodialysis by the Double Conjugate Salts Stress

Preparation of Hypophosphorous Acid by Bipolar Membrane Electrodialysis: Process Optimization and Phosphorous Acid Minimization

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Preliminary study on preparation of ammonium metatungstate from ammonium tungstate solutions using bipolar membrane electrodialysis

Cited by 12 publications

References 3 publications

Ultrasonic Spray Pyrolysis‐assisted Fabrication of Ultrathin CuWO4 Films with Improved Photoelectrochemical Performance

Ultrasonic Spray Pyrolysis‐assisted Fabrication of Ultrathin CuWO4 Films with Improved Photoelectrochemical Performance

The Novel Strategy for Increasing the Efficiency and Yield of the Bipolar Membrane Electrodialysis by the Double Conjugate Salts Stress

Preparation of Hypophosphorous Acid by Bipolar Membrane Electrodialysis: Process Optimization and Phosphorous Acid Minimization

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Ultrasonic Spray Pyrolysis‐assisted Fabrication of Ultrathin CuWO₄ Films with Improved Photoelectrochemical Performance

Ultrasonic Spray Pyrolysis‐assisted Fabrication of Ultrathin CuWO₄ Films with Improved Photoelectrochemical Performance