Determination of Kjeldahl Nitrogen and Exchangeable Ammonium in Soil by the Indophenol Method

Wang, L.; Øien, A.

doi:10.1080/00015128609435795

Cited by 18 publications

(4 citation statements)

References 10 publications

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“…After 1 h illumination, the catalyst in the reaction solution was removed by centrifugation. The amount of NH 3 /NH 4+ produced was then determined using the indoxyl blue method . The amount of NH 3 /NH 4+ was quantified by an ultraviolet–visible spectrophotometer after 2 h. p -(Dimethylamino-benzaldehyde) was used to check for N 2 H 4 byproducts …”

Section: Methodsmentioning

confidence: 99%

Limitation of WO₃ in Zn-Co₃O₄ Nanopolyhedra by the Pyrolysis of H₃PW₁₂O₄₀@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation

Yang

et al. 2023

Inorg. Chem.

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The photocatalytic nitrogen fixation process is a crucial step toward carbon neutrality and sustainable development. The combination of polyoxometalates and metal–organic frameworks is a viable method to achieve high-efficiency photocatalytic nitrogen fixation. In this work, we employed bimetallic ZIF (BMZIF) composed of Co2+ and Zn2+ encapsulated with H3PW12O40 (PW12) as the precursor to synthesize Zn-doped Co3O4 nanopolyhedra loaded with WO3 nanoparticles. The NH3 yield of WO3/Zn-Co3O4-2 with the best photocatalytic performance can reach 231.9 μmol g–1 h–1 under visible light, about 2.4 and 6.4 times those of pure Zn-Co3O4 and WO3, respectively. The rhombic dodecahedral geometry of BMZIF is still maintained in the synthesized WO3/Zn-Co3O4 nanopolyhedra, with the significant increase in the specific surface area after calcination showing better catalytic performance. At the same time, Zn doping and the formation of WO3 nanoparticles result in abundant oxygen vacancies in WO3/Zn-Co3O4 heterostructures. Oxygen vacancies can supply nitrogen with active sites for adsorption and activation and improve photocarriers’ capacity for separation, which can greatly increase the effectiveness of the photocatalytic synthesis of ammonia. This work can easily synthesize the heterostructure based on n-type WO3 nanoparticles and p-type Zn-doped Co3O4 nanopolyhedra, and the beneficial combination of POMs and metal–organic framework provides new thinking for the synthesis of efficient nitrogen-fixing photocatalysts.

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Section: Methodsmentioning

confidence: 99%

Limitation of WO₃ in Zn-Co₃O₄ Nanopolyhedra by the Pyrolysis of H₃PW₁₂O₄₀@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation

Yang

et al. 2023

Inorg. Chem.

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“…After the photocatalytic test was completed, the catalyst in the reaction solution was removed by centrifugation at a speed of 10,000 r min −1 . Then, the concentration of NH 3 /NH 4 + generated during the reaction was measured by Indophenol Blue method [14,15]. 2.5 mL of the above centrifugal solution was put into a centrifuge tube and diluted to 5 mL with ultrapure-water.…”

Section: Photocatalytic Nitrogen Fixation Testsmentioning

confidence: 99%

Construction of Co3O4 nanopolyhedra with rich oxygen vacancies from ZIF-67 for efficient photocatalytic nitrogen fixation

Wang

et al. 2023

Photochem Photobiol Sci

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Photocatalytic nitrogen fixation has attracted much attention due to the fact that it is a way of using solar energy to achieve clean and sustainable conversion of nitrogen to ammonia under mild conditions. In this paper, different proportions of Zn-doped Co 3 O 4 nanopolyhedrons were synthesized using bimetallic ZIFs containing Co 2+ and Zn 2+ as precursors for the construction of photocatalytic nitrogen fixation semiconductor materials for the first time. The synthesized Co 3 O 4 nanopolyhedron still retains the rhombic dodecahedron shape of ZIF-67 and exhibits a large specific surface area. Moreover, Zn doping results in abundant oxygen vacancies on the surface of Co 3 O 4 polyhedron. These oxygen vacancies not only provide active sites for nitrogen adsorption and activation, but also enhance the separation ability of photocarriers, which can significantly improve the efficiency of photocatalytic nitrogen fixation of the material. When Zn-Co 3 O 4 -30 is utilized as the catalyst for photocatalytic nitrogen fixation, the nitrogen fixation rate is 96.8 μmol g −1 h −1 , which is much higher than that of pure-Co 3 O 4 . In this study, heteroatom-doped Co 3 O 4 polyhedron with rich oxygen vacancy was synthesized by low-temperature oxidation method, which provides a new idea for the design and synthesis of skeleton-based photocatalytic nitrogen fixation materials.

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“…Ammonium determination was carried out by means of a colorimetric method through the formation of a coloured complex of indophenol blue according to the procedure described by Wang and Oien [22]. The determinations were performed in triplicate.…”

Section: Url: Wwwonlinesciencepublishingcom | June 2022mentioning

confidence: 99%

NH4+ Fixation and Ionic Competition with K+ in a Clayey Soil from Ocumare Del Tuy, Venezuela

et al. 2022

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Ammonium and potassium are essential for plant production, both share an ionic potential capable of entering the structure of some 2:1 type clay minerals, remaining fixed. Although, in Venezuela there are abundant areas with the presence of this type of clays, ammonium fixation (NH4f) has been little studied. The soil studied located in Los Valles del Tuy, Miranda State, presented clayey texture, some textural homogenization, and little differentiation in horizons, which is characteristic of Inceptisols. That soil also evidenced by XRD the abundant presence of nontronite / montmorillonite, resulting in a semi-quantification of 20% and 16.4% for the surface and subsoil horizons, respectively. The fixation of ammonium and the competition with potassium to occupy the fixed sites of these clays were studied by means of an incubation experiment, varying the concentration of K+ and keeping the concentration of NH4+ fixed, then extracting and determining the fixed ammonium by a photocolorimetry method. The soil presented a great ammonium fixing capacity, 49% of the total added was fixed in the absence of the competitive ion; however, NH4f fell drastically when both ions were added simultaneously, decreasing exponentially under increasing amounts of the competitive ion and staying constant around 8%. It seems possible that, the high toxicity induced by excessive fertilisation with ammonium sulfate could be counteracted in soils with capacity to retain K, if, at the expense of Kf, the levels of K in the soil solution are increased causing a decrease in the concentrations of N in the tissue.

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Determination of Kjeldahl Nitrogen and Exchangeable Ammonium in Soil by the Indophenol Method

Cited by 18 publications

References 10 publications

Limitation of WO₃ in Zn-Co₃O₄ Nanopolyhedra by the Pyrolysis of H₃PW₁₂O₄₀@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation

Limitation of WO₃ in Zn-Co₃O₄ Nanopolyhedra by the Pyrolysis of H₃PW₁₂O₄₀@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation

Construction of Co3O4 nanopolyhedra with rich oxygen vacancies from ZIF-67 for efficient photocatalytic nitrogen fixation

NH4+ Fixation and Ionic Competition with K+ in a Clayey Soil from Ocumare Del Tuy, Venezuela

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Determination of Kjeldahl Nitrogen and Exchangeable Ammonium in Soil by the Indophenol Method

Cited by 18 publications

References 10 publications

Limitation of WO3 in Zn-Co3O4 Nanopolyhedra by the Pyrolysis of H3PW12O40@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation

Limitation of WO3 in Zn-Co3O4 Nanopolyhedra by the Pyrolysis of H3PW12O40@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation

Construction of Co3O4 nanopolyhedra with rich oxygen vacancies from ZIF-67 for efficient photocatalytic nitrogen fixation

NH4+ Fixation and Ionic Competition with K+ in a Clayey Soil from Ocumare Del Tuy, Venezuela

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Limitation of WO₃ in Zn-Co₃O₄ Nanopolyhedra by the Pyrolysis of H₃PW₁₂O₄₀@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation

Limitation of WO₃ in Zn-Co₃O₄ Nanopolyhedra by the Pyrolysis of H₃PW₁₂O₄₀@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation