Nontronite mineral clay NAu-2 as support for hematite applied as catalyst for heterogeneous photo-Fenton processes

Rojas-Mantilla, Hernán Dario; Ayala-Durán, Saidy Cristina; Nogueira, Raquel Fernandes Pupo

doi:10.1016/j.chemosphere.2021.130258

Cited by 17 publications

(6 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rojas-Mantilla et al, recently characterized the nontronite mineral present in clay [51]. Nontronite contains structural iron in higher proportions.…”

Section: Crystalline Structurementioning

confidence: 99%

X-ray Diffraction Techniques for Mineral Characterization: A Review for Engineers of the Fundamentals, Applications, and Research Directions

2022

View full text Add to dashboard Cite

X-ray diffraction (XRD) is an important and widely used material characterization technique. With the recent development in material science technology and understanding, various new materials are being developed, which requires upgrading the existing analytical techniques such that emerging intricate problems can be solved. Although XRD is a well-established non-destructive technique, it still requires further improvements in its characterization capabilities, especially when dealing with complex mineral structures. The present review conducts comprehensive discussions on atomic crystal structure, XRD principle, its applications, uncertainty during XRD analysis, and required safety precautions. The future research directions, especially the use of artificial intelligence and machine learning tools, for improving the effectiveness and accuracy of the XRD technique, are discussed for mineral characterization. The topics covered include how XRD patterns can be utilized for a thorough understanding of the crystalline structure, size, and orientation, dislocation density, phase identification, quantification, and transformation, information about lattice parameters, residual stress, and strain, and thermal expansion coefficient of materials. All these important discussions on XRD analysis for mineral characterization are compiled in this comprehensive review, so that it can benefit specialists and engineers in the chemical, mining, iron, metallurgy, and steel industries.

show abstract

“…Rojas-Mantilla et al, recently characterized the nontronite mineral present in clay [51]. Nontronite contains structural iron in higher proportions.…”

Section: Crystalline Structurementioning

confidence: 99%

X-ray Diffraction Techniques for Mineral Characterization: A Review for Engineers of the Fundamentals, Applications, and Research Directions

2022

View full text Add to dashboard Cite

show abstract

“…The chemical composition in wt % of NAu-2 raw material given by the Clay Minerals Society is SiO 2 56.99, Al 2 O 3 3.4, Fe 2 O 3 37.42, MgO 0.34, CaO 2.67, Na 2 O 0.11, K 2 O 0.02, and its chemical formula is (M + 0.97 )[Si 7.57 Al 0.01 Fe 0.42 ][Al 0.52 Fe 3.32 Mg 0.7 ]O 20 (OH) 4. According to several sources, the Fe content varies between 21 and 38 wt % . In our study, the Fe content of native NAu-2 is 22 wt % as determined by X-Ray Fluorescence (XRF).…”

Section: Materials and Methodsmentioning

confidence: 87%

Oxidation State and Structure of Fe in Nontronite: From Oxidizing to Reducing Conditions

Qian,

Scheinost,

Grangeon

et al. 2023

ACS Earth Space Chem.

View full text Add to dashboard Cite

The redox reaction between natural Fe-containing clay minerals and its sorbates is a fundamental process controlling the cycles of many elements such as carbon, nutrients, redoxsensitive metals, and metalloids (e.g., Co, Mn, As, Se), and inorganic as well as organic pollutants in Earth's critical zone. While the structure of natural clay minerals under oxic conditions is wellknown, less is known about their behavior under anoxic and reducing conditions, thereby impeding a full understanding of the mechanisms of clay-driven reduction and oxidation (redox) reactions especially under reducing conditions. Here we investigate the structure of a ferruginous natural clay smectite, nontronite, under different redox conditions, and compare several methods for the determination of iron redox states. Iron in nontronite was gradually reduced chemically with the citrate-bicarbonate-dithionite (CBD) method. 57 Fe Mossbauer spectrometry, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) spectroscopy including its pre-edge, extended Xray absorption fine structure (EXAFS) spectroscopy, and mediated electrochemical oxidation and reduction (MEO/MER) provided consistent Fe(II)/Fe(III) ratios. By combining X-ray diffraction (XRD) and transmission electron microscopy (TEM), we show that the long-range structure of nontronite at the highest obtained reduction degree of 44% Fe(II) is not different from that of fully oxidized nontronite except for a slight basal plane dissolution on the external surfaces. The short-range order probed by EXAFS spectroscopy suggests, however, an increasing structural disorder and Fe clustering with increasing reduction of structural Fe.

show abstract

“…Several researchers have looked at the relationship between iron content, catalytic behavior, and temperature. Increases in the tested parameters, such as the maximum iron content of 2.6 mM and the maximum temperature of 70 ℃, resulted in an increase in reaction rate (Cuervo Lumbaque et al 2021;Guo et al 2021;Rojas-Mantilla et al 2021;Subramanian and Prakash 2021). Just one study looks at what happens when time intervals with and without illumination are alternated.…”

Section: Factors Influencing the Photo-fenton Processmentioning

confidence: 99%

“…Furthermore, catalyst renewal is impractical, and a significant proportion of catalytic metal is lost in the sludge. The use of heterogeneous catalysts can help overcome some of these constraints (Rojas-Mantilla et al 2021;Saber et al 2021).…”

Section: Factors Influencing the Photo-fenton Processmentioning

confidence: 99%

Solar photo-oxidation of recalcitrant industrial wastewater: a review

et al. 2022

View full text Add to dashboard Cite

Conventional methods to clean wastewater actually lead to incomplete treatments, calling for advanced technologies to degrade recalcitrant pollutants. Herein we review solar photo-oxidation to degrade the recalcitrant contaminants in industrial wastewater, with focus on photocatalysts, reactor design and the photo-Fenton process. We discuss limitations due to low visible-light absorption, catalyst collection and reusability, and production of toxic by-products. Photodegradation of refractory organics by solar light is controlled by pH, photocatalyst composition and bandgap, pollutant properties and concentration, irradiation type and intensity, catalyst loading, and the water matrix.

show abstract

Nontronite mineral clay NAu-2 as support for hematite applied as catalyst for heterogeneous photo-Fenton processes

Cited by 17 publications

References 53 publications

X-ray Diffraction Techniques for Mineral Characterization: A Review for Engineers of the Fundamentals, Applications, and Research Directions

X-ray Diffraction Techniques for Mineral Characterization: A Review for Engineers of the Fundamentals, Applications, and Research Directions

Oxidation State and Structure of Fe in Nontronite: From Oxidizing to Reducing Conditions

Solar photo-oxidation of recalcitrant industrial wastewater: a review

Contact Info

Product

Resources

About