EPR, FT-IR and XRD investigation of soils from Paraná, Brazil

Siqueira, R.E.; Andrade, Milena Martins; Valezi, Daniel Farinha; Carneiro, Cristine Elizabeth Alvarenga; Pinese, José Paulo Peccinini; Costa, Antônio Carlos Saraiva da; Zaia, Dimas Augusto Morozin; Ralisch, Ricardo; Pontuschka, W. M.; Guedes, Carmen Luı́sa Barbosa; Mauro, Eduardo Di

doi:10.1016/j.clay.2011.04.018

Cited by 27 publications

(8 citation statements)

References 19 publications

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“…AOS had an absorption peak at 1725 cm −1 (–COOH) (Dolamic et al ., ) that was absent in the AOS–iron (III) spectrum, which indicates that –COOH might be chelated with iron (III). In addition, bands at 1636 and 1412 cm −1 in the AOS spectrum indicated the presence of a free carboxylic carbonyl group (Siqueira et al ., ; Pouyet et al ., ) and carboxylic acids group (Xu et al ., ), respectively. In the AOS–iron (III) spectrum, the two peaks showed some migration (1605 and 1386 cm −1 ), which means that iron (III) and AOS might be combined by the –OH groups (Tang et al ., ).…”

Section: Resultsmentioning

confidence: 98%

Preparation and characterisation of a novel agar oligosaccharide–iron (III) complex

Teng

et al. 2018

Int J of Food Sci Tech

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This study aimed to synthesise a complex of agar oligosaccharides (AOS) with ferric iron and to evaluate its physicochemical and structural characteristics. Based on single factor, Plackett-Burman and response surface optimal experiments of three factors at three levels, the optimised chelate conditions of the AOSiron (III) complex were mass ratio of AOS to iron ions of 4.5:1 g:g, reaction temperature of 74°C and reaction time of 60 min. Under these conditions, the iron content and total sugar content were 14.03 AE 0.42% and 66.07 AE 0.96%, respectively. The physicochemical analysis showed that AOS-iron (III) was soluble and steady at physiological pH, and it was easily reduced to iron (II). The structural characteristics of AOS and AOS-iron (III) were analysed by Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and Nuclear magnetic resonance, and results showed that the iron (III) ions were chelated to AOS by -OH groups and -COOH groups and widely dispersed on the AOS backbone. Therefore, AOS-iron (III) could be a candidate for iron supplementation to treat iron deficiency anaemia.

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Section: Resultsmentioning

confidence: 98%

Preparation and characterisation of a novel agar oligosaccharide–iron (III) complex

Teng

et al. 2018

Int J of Food Sci Tech

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“…Comparisons were made with the ESR spectra of hematite and other minerals [2] and no relationship was found with our spectra. XRD measurements were also performed at room temperature, before and after heat treatment of the samples, in order to completely exclude the possibility that the changes in the ESR signal were connected to chemical transformations.…”

Section: Additional Considerationsmentioning

confidence: 93%

“…This mineral is one of the most abundant iron compounds in nature and it is part of various types of soils [1], as well as hematite, kaolinite and ferrihydrite [2]. Goethite is also contained in sediments, rock erosion and steel corrosion products.…”

Section: Introductionmentioning

confidence: 99%

Goethite (α-FeOOH) magnetic transition by ESR, Magnetometry and Mössbauer

Valezi

Piccinato

Sarvezuk

et al. 2016

Materials Chemistry and Physics

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“…Redox reactions and the formation of free radicals still require explanation, however. Electron paramagnetic resonance (EPR) enables investigation of these phenomena as well as the identification of inorganic radicals, because it is highly sensitive to paramagnetic species such as Fe 3+ and Mn 2+ (Kudynska et al, 1989;Siqueira et al, 2011). These species often occur as minor elements at low concentrations substituting for the main components in the structures of the clay minerals.…”

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confidence: 99%

MAS NMR and EPR study of structural changes in talc and montmorillonite induced by grinding

2016

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The milling process in the solid-state 2:1 clay minerals, montmorillonite and talc, which have different cation exchange capacities, is reported here. Several instrumental techniques were used to monitor systematically the products formed. The dehydroxylation/amorphization of the montmorillonite and talc structures occurs within 3 and 6 h of milling, respectively. Electron paramagnetic resonance spectra indicated that structural Mn2+ was oxidized more quickly in the montmorillonite structure than in talc, while the paramagnetic defects increased during milling. Nuclear magnetic resonance was also used to monitor the environmental changes for Si and Al during milling.

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EPR, FT-IR and XRD investigation of soils from Paraná, Brazil

Cited by 27 publications

References 19 publications

Preparation and characterisation of a novel agar oligosaccharide–iron (III) complex

Preparation and characterisation of a novel agar oligosaccharide–iron (III) complex

Goethite (α-FeOOH) magnetic transition by ESR, Magnetometry and Mössbauer

MAS NMR and EPR study of structural changes in talc and montmorillonite induced by grinding

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