XPS study on the mechanism of starch-hematite surface chemical complexation

Moreira, Gabriela F.; Peçanha, Elaynne Rohem; Monte, Marisa Bezerra de Mello; Filho, Laurindo de Salles Leal; Stavale, Fernando

doi:10.1016/j.mineng.2017.04.014

Cited by 149 publications

(37 citation statements)

References 39 publications

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“…The Zeta potentials of aegirite and specularite at different pH values were measured, and the result is illustrated in Figure 8. As shown in Figure 8, the Zeta potentials of these two minerals both decreased with the increase of pH value, and the IEP of specularite (2.83) is higher than that of aegirite (2.12), which conforms to the conjecture and previous results [11,40]. As a cationic collector, DDA increases the surface potential when adsorbed on a mineral surface.…”

Section: Surface Charge Of Mineral Surfacesupporting

confidence: 89%

“…Based on the type of gangue, iron ore can be classified into three major types: quartz-type, carbonate-type, and silicate-type [3][4][5][6]. The difficulty of quartz-type iron ore separation via flotation is relatively low, and extensive studies have been conducted that mainly focus on the flotation separation of quartz-type oxide iron ore or the novel reagent synthesis and adsorption mechanism [7][8][9][10][11][12]. However, silicate-type iron ore, especially the iron-containing silicate-type iron ores, such as aegirite, chlorite, grunerite, garnet, etc., is difficult to separate due to the similar magnetic and floatability properties between iron-containing silicate and oxidized iron ore [13].…”

Section: Introductionmentioning

confidence: 99%

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Surface Properties and Floatability Comparison of Aegirite and Specularite by Density Functional Theory Study and Experiment

Gao

et al. 2019

Minerals

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Understanding the differences in surface properties between aegirite and specularite is of great significance to study their separation. In this work, the surface properties of aegirite and specularite, as well as their relationships to floatability, have been explored by first principle calculation, flotation, and Zeta potential measurement. The surface relaxation indicated that the specularite (001) surface appeared to show more surface reconstruction. The unsatisfied bond properties, Mulliken bond population, and surface charge showed that the floatability of specularite was superior to that of aegirite. The flotation results showed that the hydrophobicity of specularite was higher than that of aegirite with dodecylamine (DDA) as the collector. It is infeasible to separate specularite from aegirite by flotation using starch as the depressant, and research of effective reagents with high affinity to the element Si is the subclinical breakthrough point of specularite/aegirite separation.Minerals 2019, 9, 782 2 of 15 flotation with amines. They also found that starch was not a selective depressant for magnetite in the process of the reverse cationic flotation of iron ores when iron-containing silicates as amphiboles are present in the flotation system [8]. Carboxymethyl cellulose, an effective depressant for iron oxide, was also found to be a depressant for chlorite [14].The novel high-efficiency depressants or collectors are considered to be an effective method to solve the unsatisfactory separation problems [15,16]. These depressants and collectors are targeted for making a sufficient hydrophilic and hydrophobic state of the mineral and gangue surface, respectively. Therefore, they are profoundly inseparable from understanding the surface properties of the minerals in the novel depressant or collector molecule design and their adsorption mechanism on the mineral surface.In recent years, with the rapid developments of theoretical and computational chemistry, a density functional theory (DFT) calculation can be adopted to visually investigate the surface properties and floatability of minerals and to predict possible novel reagents [4,17]. The wettability of the mineral surface and its regulation have always been the core issues of the flotation process [18][19][20]. Thus, further research of the nature of the cleavage surface, especially of the main cleavage surface, is of great significance for investigating the floatability of the minerals. For example, Han et al. [21] calculated the surface properties of the hemimorphite (110) surface and the simthsointe (101) surface by the first-principle calculation method to investigate their relationships to the mineral floatability, which implied that hemimorphite (110) surface is more readily wetted by water, while the O atoms on hemimorphite (110) surface are more impeding of collector molecules. He et al. [22] calculated the properties of spodumene and revealed that the O atoms in spodumene are the most active, while the Li atoms are inactive, so an activator is nece...

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Section: Surface Charge Of Mineral Surfacesupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Surface Properties and Floatability Comparison of Aegirite and Specularite by Density Functional Theory Study and Experiment

Gao

et al. 2019

Minerals

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“…The binding energy of the Ca2p 3/2 peak increases from 348.07 to 348.58 eV, and the binding energy of the Ca2p 1/2 peak also increases from 351.58 to 352.08 eV, showing corresponding chemical shifts of 0.51 and 0.5 eV, relative to the binding energies before PA-Na addition (Figure 11a). When the chemical shift is greater than the experimental error of 0.3 eV, it indicates that a chemical reaction occurs; the greater the chemical shift, the stronger the reaction [38,39]. The increase in the binding energy of the fluorite surface after PA-Na addition implies the existence of a strong force of adsorption on fluorite.…”

Section: Adsorption Energymentioning

confidence: 98%

Flotation Separation of Scheelite from Fluorite Using Sodium Polyacrylate as Inhibitor

Zhang

Chen

et al. 2017

Minerals

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Abstract:The depressing properties of sodium polyacrylate (PA-Na) for scheelite and fluorite were studied by micro-flotation tests, infrared spectroscopy (IR), zeta potentials, X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT). The flotation results reveal that the selective depression effect of PA-Na is better than that of sodium silicate, and PA-Na can depress fluorite more effectively than scheelite. The flotation recovery of scheelite and fluorite keeps at about 75% and 10%, respectively, at the pulp pH 9.3~9.6 and PA-Na concentration from 30 to 50 mg/L. IR spectra results suggest that PA-Na has a chemical effect on the surface of scheelite and fluorite. The zeta potential of fluorite becomes more negative than that of scheelite after PA-Na addition. XPS analysis deduces the occurrence of chemisorption between PA-Na and mineral surfaces, and the chemisorption of PA-Na on fluorite is stronger than on scheelite. DFT demonstrates that the absolute value of the adsorption energy in the presence of PA-Na is larger on the fluorite {111} surface than on the scheelite {111} surface. Thus, fluorite is more readily depressed than scheelite, which remarkably matches the micro-flotation test results.

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“…Comparing the fitted C1sX PS spectra of the unmodified ex-pandedH ACS (4a)a nd S350 (4b)s upports to those of Fe-NHC catalysts 1a and 1b ( Figure S10 andS 11), additional carbon peaks at 283.6, 286.1 and 289.2 assigned to CÀC(Ar), C-N and C=Oa re observed. [31] These additional peaks are believed to come from compound (12)a ttached on the expanded HACS.…”

Section: Mçssbauerspectroscopymentioning

confidence: 99%

Starbon/High‐Amylose Corn Starch‐Supported N‐Heterocyclic Carbene–Iron(III) Catalyst for Conversion of Fructose into 5‐Hydroxymethylfurfural

et al. 2018

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Iron-N-heterocyclic carbene complexes (Fe-NHCs) have come to prominence because of their applicability in diverse catalytic reactions, ranging from C-C cross-coupling and C-X bond formation to substitution, reduction, polymerization, and dehydration reactions. The detailed synthesis, characterization, and application of novel heterogeneous Fe-NHC catalysts immobilized on mesoporous expanded high-amylose corn starch (HACS) and Starbon 350 (S350) for facile fructose conversion into 5-hydroxymethylfurfural (HMF) is reported. Both catalyst types showed good performance for the dehydration of fructose to HMF when the reaction was tested at 100 °C with varying time (10 min, 20 min, 0.5 h, 1 h, 3 h and 6 h). For Fe-NHC/S350, the highest HMF yield was 81.7 % (t=0.5 h), with a TOF of 169 h , fructose conversion of 95 %, and HMF selectivity of 85.7 %, whereas for Fe-NHC/expanded HACS, the highest yield was 86 % (t=0.5 h), with a TOF of 206 h , fructose conversion of 87 %, and HMF selectivity of 99 %. Iron loadings of 0.26 and 0.30 mmol g were achieved for Fe-NHC/expanded starch and Fe-NHC/S350, respectively.

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XPS study on the mechanism of starch-hematite surface chemical complexation

Cited by 149 publications

References 39 publications

Surface Properties and Floatability Comparison of Aegirite and Specularite by Density Functional Theory Study and Experiment

Surface Properties and Floatability Comparison of Aegirite and Specularite by Density Functional Theory Study and Experiment

Flotation Separation of Scheelite from Fluorite Using Sodium Polyacrylate as Inhibitor

Starbon/High‐Amylose Corn Starch‐Supported N‐Heterocyclic Carbene–Iron(III) Catalyst for Conversion of Fructose into 5‐Hydroxymethylfurfural

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