A Spectrophotometric Study of Nitrate and Nitrite Salts and Their Aqueous Solutions

Aluker, N. L.; Herrmann, Maria; Suzdaltseva, Ya. M.

doi:10.1134/s0030400x19120026

Cited by 14 publications

(7 citation statements)

References 7 publications

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“…1b). Formation of the latter signals is independent on the H 2 O 2 presence, and these bands can be attributed to nitrates or other nickel-oxygen compounds [63,64] which are formed during NH 3 oxidation at the platinum anode [65,66]. These signals eventually overlap the main Ni peak at ca.…”

Section: In Situ Uv-vis Analysis Of the Plating Processmentioning

confidence: 99%

Electrochemical deposition of nickel from aqueous electrolytic baths prepared by dissolution of metallic powder

Próchniak

Grdeń

2021

J Solid State Electrochem

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A new method of preparation of aqueous electrolyte baths for electrochemical deposition of nickel targets for medical accelerators is presented. It starts with fast dissolution of metallic Ni powder in a HNO3-free solvent. Such obtained raw solution does not require additional treatment aimed to removal nitrates, such as the acid evaporation and Ni salt precipitation-dissolution. It is used directly for preparation of the nickel plating baths after dilution with water, setting up pH value and after possible addition of H3BO3. The pH of the baths ranges from alkaline to acidic. Deposition of 95% of ca. 50 mg of Ni dissolved in the bath takes ca. 3.5 h for the alkaline electrolyte while for the acidic solution it requires ca. 7 h. The Ni deposits obtained from the acidic bath are physically and chemically more stable and possess smoother and crack-free surfaces as compared to the coatings deposited from the alkaline bath. A method of estimation of concentration of H2O2 in the electrolytic bath is also proposed.

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Section: In Situ Uv-vis Analysis Of the Plating Processmentioning

confidence: 99%

Electrochemical deposition of nickel from aqueous electrolytic baths prepared by dissolution of metallic powder

Próchniak

Grdeń

2021

J Solid State Electrochem

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“…Figure 2 shows absorbance results in the visible spectrum between 400 and 800 nm wavelength. Nitrate (𝑁𝑂 ) ions absorb light in the UV spectrum, i.e., between 200 and 400 nm [27]. Nitrate ions were present in samples containing dissolved HAN.…”

Section: Absorbancementioning

confidence: 99%

Effect of Metal Sequestrants on the Decomposition of Hydroxylammonium Nitrate

Broemmelsiek

Rovey

Berg³

2021

Catalysts

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Hydroxylammonium nitrate (HAN) is an energetic salt used in flight-proven green monopropellants such as ASCENT (formerly AF-M315E), flown in NASA’s 2019 Green Propellant Infusion Mission, and SHP163, flown in JAXA’s Rapid Innovative Satellite Technology Demonstration-1. The decomposition of HAN is catalyzed by metals commonly found in storage tanks, a factor limiting its use. This work investigates the ability of metal-sequestering chelating agents to inhibit the decomposition of HAN. Isothermal and dynamic thermogravimetric analysis (TGA) were used to find isothermal decomposition rates, decomposition onset temperatures, and first-order Arrhenius reaction rate parameters. In the present research, 2,2′-bipyridine (Bipy), triethanolamine (TEA), and ethylenediaminetetraacetic acid (EDTA) were studied as 0.05, 0.1, 0.5, 1, and 5% by weight additives in 90% aqueous HAN. An isothermal decomposition rate of 0.137%/h at 348 K was observed for HAN. The addition of 1% Bipy and 1% TEA reduced the isothermal decomposition rate by 20.4% to 0.109%/h, and by 3.65% to 0.132%/h, respectively, showing that Bipy can inhibit decomposition. The addition of 1% EDTA increased the isothermal decomposition rate by 12.4% to 0.154%/h. Bipy was found to increase the decomposition onset temperature from 454.8 K to 461.8 K, while the results for TEA and EDTA were inconclusive. First order reaction rates calculated by the Ozawa-Flynn-Wall method were found to be insufficient to capture the effects of the tested additives. Bipy was found to inhibit the decomposition of HAN, while TEA and EDTA produced little or negative effect, a result believed to be due to poor metal complex stability at low pH and high acidity, respectively. Spectrophotometry, used for colorimetric analysis of Bipy+iron complexes, showed that Bipy forms chelate complexes with trace iron impurities when added to HAN solutions.

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“…A similar study reported that nitrate has a primary and secondary peak at 202 nm and 302 nm, respectively. In contrast, for nitrite, the primary and secondary peaks appeared at 210 nm and 355 nm, respectively [11]. However, at a low level of nitrate and nitrite usually produced in typical chloraminated drinking water during nitrification, the secondary peak is unsuitable to detect and measure because of the inadequate response at that wavelength.…”

Section: Introductionmentioning

confidence: 96%

“…[9,10]. Over many years, optical techniques have been successfully used to measure a range of water quality parameters, including dissolved organic carbon (DOC), nitrate, nitrite, and monochloramine, with an excellent limit of detection [11][12][13][14]. Singh et al [2] reviewed various spectroscopic methods and concluded that UV-Vis spectrophotometry is widely accepted because of its simplicity, feasibility, and versatility.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies have reported the application of different data analytic techniques for the determination of nitrate and nitrite using single or multi-wavelength absorption spectra [1,8,11,13,15,[17][18][19][20][21][22]. For instance, Karlsson et al [8] used multivariate data analysis to relate spectra and concentrations of municipal wastewater.…”

Section: Introductionmentioning

confidence: 99%

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Development of an Optical Method to Monitor Nitrification in Drinking Water

Hossain

Cook

Chow

et al. 2021

Sensors

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Nitrification is a common issue observed in chloraminated drinking water distribution systems, resulting in the undesirable loss of monochloramine (NH2Cl) residual. The decay of monochloramine releases ammonia (NH3), which is converted to nitrite (NO2−) and nitrate (NO3−) through a biological oxidation process. During the course of monochloramine decay and the production of nitrite and nitrate, the spectral fingerprint is observed to change within the wavelength region sensitive to these species. In addition, chloraminated drinking water will contain natural organic matter (NOM), which also has a spectral fingerprint. To assess the nitrification status, the combined nitrate and nitrite absorbance fingerprint was isolated from the total spectra. A novel method is proposed here to isolate their spectra and estimate their combined concentration. The spectral fingerprint of pure monochloramine solution at different concentrations indicated that the absorbance difference between two concentrations at a specific wavelength can be related to other wavelengths by a linear function. It is assumed that the absorbance reduction in drinking water spectra due to monochloramine decay will follow a similar pattern as in ultrapure water. Based on this criteria, combined nitrate and nitrite spectra were isolated from the total spectrum. A machine learning model was developed using the support vector regression (SVR) algorithm to relate the spectral features of pure nitrate and nitrite with their concentrations. The model was used to predict the combined nitrate and nitrite concentration for a number of test samples. Out of these samples, the nitrified sample showed an increasing trend of combined nitrate and nitrite productions. The predicted values were matched with the observed concentrations, and the level of precision by the method was ± 0.01 mg-N L−1. This method can be implemented in chloraminated distribution systems to monitor and manage nitrification.

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A Spectrophotometric Study of Nitrate and Nitrite Salts and Their Aqueous Solutions

Cited by 14 publications

References 7 publications

Electrochemical deposition of nickel from aqueous electrolytic baths prepared by dissolution of metallic powder

Electrochemical deposition of nickel from aqueous electrolytic baths prepared by dissolution of metallic powder

Effect of Metal Sequestrants on the Decomposition of Hydroxylammonium Nitrate

Development of an Optical Method to Monitor Nitrification in Drinking Water

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