Surface nanobubbles on the carbonate mineral dolomite

Owens, Camilla L.; Schach, Edgar; Rudolph, Martin; Nash, George

doi:10.1039/c8ra07952h

Cited by 12 publications

(9 citation statements)

References 32 publications

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“…Surface nanobubbles are typical gaseous domains at the micro/nanoscale forming at a solid–liquid interface, − which have attracted significant interest because of their potential applications, such as liquid flow friction reduction, − fouling prevention, heterogeneous cavitation, and froth flotation. , Most studies about surface nanobubbles are on atomically flat substrates such as highly oriented pyrolytic graphite , and mica, , mineral dolomite, polymer-coated substrates such as polystyrene (PS) films − and poly(dimethylsiloxane) (PDMS) films, hydrophobized glass, , as well as self-assembled monolayer (SAM)-modified Si , and SAMs on Au. , Surface nanobubbles have been investigated extensively in the last two decades. However, there is still much debate on whether the bubble-like domains on immersed substrates are gas bubbles or not.…”

Section: Introductionmentioning

confidence: 99%

Properties of Blisters Formed on Polymer Films and Differentiating them from Nanobubbles/Nanodrops

Liu²,

Qi³

et al. 2019

Langmuir

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When studying surface nanobubbles on film-coated substrates, a class of bubble-like domains called blisters are probably forming at the solid–liquid interface together with nanobubbles. This may easily lead to a misunderstanding of the characteristics and applications of surface nanobubbles and thus continue to cause problems within the nanobubble community. Therefore, how to distinguish surface nanobubbles from blisters is a problem. Herein, the morphology and properties of blisters are investigated on both smooth and nanopitted polystyrene (PS) films in degassed water. The morphology and contact angle of blisters are similar to those of surface nanobubbles. However, blisters were observed to be punctured under the tip–blister interaction and be torn broken by an atomic force microscope tip during the process of scanning. At the same time, nanopits on the surface of blisters that formed on a pitted PS film can be seen clearly. These provide direct and visual evidence for distinguishing blisters from surface nanobubbles. In addition, surface nanobubbles and blisters on smooth and pitted PS films in air-equilibrated water are studied. No punctured surface nanobubble was observed, and the force curves obtained on surface nanobubbles and the change in height of blisters and surface nanobubbles under a large scanning force show that surface nanobubbles are much softer than blisters.

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Section: Introductionmentioning

confidence: 99%

Properties of Blisters Formed on Polymer Films and Differentiating them from Nanobubbles/Nanodrops

Liu²,

Qi³

et al. 2019

Langmuir

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“…Some hints on this were found using AFM ( Figure 1 and Figure 2 , and Refs. [ 18 , 21 , 22 ]) and cryo-XPS [ 19 , 20 ]. The formation of nanobubbles on essentially oxidized hydrophilic surfaces seems to be suppressed.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, quasi in situ X-ray photoelectron spectroscopy (XPS) studies of the particulate sulfide minerals reacted with xanthate in the slurries, centrifuged and then fast-frozen [ 19 , 20 ], revealed charging effects attributed to cavities separating the hydrophobized mineral particles which may be signatures of gas structures arising on the surfaces under the flotation-related conditions. Owens and co-workers [ 21 , 22 ] have imaged, with non-contact atomic force microscopy, surface nanobubbles on polished cross sections of dolomite and rare earth fluorcarbonate mineral synchysite treated with flotation collectors inducing hydrophobicity of the minerals. Xing et al [ 23 ] have surveyed the hydrophobic force in particle–bubble attachment and concluded that the role of nanobubbles still remains to be identified.…”

Section: Introductionmentioning

confidence: 99%

Towards Understanding the Role of Surface Gas Nanostructures: Effect of Temperature Difference Pretreatment on Wetting and Flotation of Sulfide Minerals and Pb-Zn Ore

et al. 2020

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Surface nanobubbles at hydrophobic interfaces now attract much attention in various fields but their role in wetting-related phenomena is still unclear. Herein, we report the effect of a preliminary contact of “hot” solids with cold water previously proposed for generation of surface nanobubbles, on wettability of compact materials and flotation of particulate galena (PbS), sphalerite (ZnS), and Pb-Zn sulfide ore. Atomic force microscopy was applied to visualize the nanobubbles at galena crystals heated in air and contacted with cold water; X-ray photoelectron spectroscopy was used to characterize the surface composition of minerals. Contact angles measured with the sessile drop of cold water were found to increase when enhancing the support temperature from 0 to 80 °C for sphalerite and silica, and to pass a maximum at 40–60 °C for galena and pyrite (FeS2) probably due to oxidation of sulfides. The temperature pretreatment depressed the recovery of sulfides in collectorless schemes and improved the potassium butyl xanthate-assisted flotation both for single minerals and Gorevskoye Pb-Zn ore. The results suggest that the surface nanobubbles prepared using the temperature difference promote flotation if minerals are rather hydrophobic and insignificantly oxidized, so the addition of collector and activator (for sphalerite) is necessary.

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“…The laboratory-based cryo-XPS has been successfully employed for exploration, among many others, of ion adsorption and electrical double layer structures [182,184], sulfur oxidation products of the reaction of goethite and lepidocrocite with aqueous sulfide [185], surfaces of chalcopyrite upon chemical and bacterial leaching [68,186], xanthate-derived collectors adsorbed on the main sulfide minerals [102,103], and other interfaces (see Figures 1 and 2 as examples). Interestingly, some signatures of surface nanobubbles, whose role in flotation is discussed at present [101,[186][187][188][189][190], were observed as highly inhomogeneous electrostatic charging of sulfide mineral particles reacted with butyl xanthates [102,103] probably due to widespread cavities and rare ice islets on the hydrophobic surfaces.…”

Section: Cryogenic Xpsmentioning

confidence: 96%

X-ray Photoelectron Spectroscopy in Mineral Processing Studies

Mikhlin

2020

Applied Sciences

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Surface phenomena play the crucial role in the behavior of sulfide minerals in mineral processing of base and precious metal ores, including flotation, leaching, and environmental concerns. X-ray photoelectron spectroscopy (XPS) is the main experimental technique for surface characterization at present. However, there exist a number of problems related with complex composition of natural mineral systems, and instability of surface species and mineral/aqueous phase interfaces in the spectrometer vacuum. This overview describes contemporary XPS methods in terms of categorization and quantitative analysis of oxidation products, adsorbates and non-stoichiometric layers of sulfide phases, depth and lateral spatial resolution for minerals and ores under conditions related to mineral processing and hydrometallurgy. Specific practices allowing to preserve volatile species, e.g., elemental sulfur, polysulfide anions and flotation collectors, as well as solid/liquid interfaces are surveyed; in particular, the prospects of ambient pressure XPS and cryo-XPS of fast-frozen wet mineral pastes are discussed. It is also emphasized that further insights into the surface characteristics of individual minerals in technological slurries need new protocols of sample preparation in conjunction with high spatial resolution photoelectron spectroscopy that is still unavailable or unutilized in practice.

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Surface nanobubbles on the carbonate mineral dolomite

Abstract: Analysis of surface nanobubbles on dolomite show that their pinning is affected by the surfactants using in mineral processing.

Cited by 12 publications

References 32 publications

Properties of Blisters Formed on Polymer Films and Differentiating them from Nanobubbles/Nanodrops

Properties of Blisters Formed on Polymer Films and Differentiating them from Nanobubbles/Nanodrops

Towards Understanding the Role of Surface Gas Nanostructures: Effect of Temperature Difference Pretreatment on Wetting and Flotation of Sulfide Minerals and Pb-Zn Ore

X-ray Photoelectron Spectroscopy in Mineral Processing Studies

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