Effect of heterogeneous hydrophobic coating on floating of insoluble particles

The influence of different wettability on explosive boiling exhibits a significant distinction, where the hydrophobic surface is beneficial for bubble nucleation and the hydrophilic surface enhances the critical heat flux. Therefore, to receive a more suitable surface for the explosive boiling, in this paper a hybrid hydrophobic–hydrophilic nanostructured surface was built by the method of molecular dynamics simulation. The onset temperatures of explosive boiling with various coating thickness, pillar width, and film thicknesses were investigated. The simulation results show that the hybrid nanostructure can decrease the onset temperature compared to the pure hydrophilic surface. It is attributed to the effect of hydrophobic coating, which promotes the formation of bubbles and causes a quicker liquid film break. Furthermore, with the increase of the hydrophobic coating thickness, the onset temperature of explosive boiling decreases. This is because the process of heat transfer between the liquid film and the hybrid nanostructured surface is inevitably enhanced. In addition, the onset temperature of explosive boiling on the hybrid wetting surface decreases with the increase of pillar width and liquid film thickness.

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Superhydrophobic Sands for the Preservation and Purification of Water

Coatings ◽

10.3390/coatings11020151 ◽

2021 ◽

Vol 11 (2) ◽

pp. 151

Author(s):

Yuyang Liu ◽

Chang-Hwan Choi

Keyword(s):

Water Surface ◽

Particulate Material ◽

Self Assembled Monolayer ◽

Hydrophobic Coatings ◽

Hydrophobic Coating ◽

Evaporation Loss ◽

Zno Nanocrystals ◽

Sand Particles ◽

Purification Of Water ◽

Nanoscale Roughness

Sand, a cheap and naturally abundant particulate material, was modified with photocatalytic and hydrophobic coatings to reduce evaporation loss and facilitate the purification of water. The first-level photocatalytic coatings (TiO2 or ZnO nanocrystals) rendered nanoscale roughness on the surface of the sand. The additional second-level hydrophobic coating of a self-assembled monolayer of octyltrimethoxysilane (OTS) made the sand particles superhydrophobic because of the nanoscale roughness imposed by the nanocrystals. The superhydrophobic sand particles, floating on the free surface of water due to their superhydrophobicity, significantly reduced the evaporation loss of water by 60%–90% in comparison to an uncovered water surface. When the outer hydrophobic coatings are weathered or disengaged, the inner photocatalytic coatings become exposed to water. Then, the sand particles act as photocatalysts to degrade the contaminants in water under solar radiation.

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Rheological Characterization of a Concentrated Phosphate Slurry

Fluids ◽

10.3390/fluids6050178 ◽

2021 ◽

Vol 6 (5) ◽

pp. 178

Author(s):

Souhail Maazioui ◽

Abderrahim Maazouz ◽

Fayssal Benkhaldoun ◽

Driss Ouazar ◽

Khalid Lamnawar

Keyword(s):

Flow Behavior ◽

Continuous Phase ◽

Raw Material ◽

Rheological Characterization ◽

Phosphate Ore ◽

Insoluble Particles ◽

Experimental Protocols ◽

Solid Liquid

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be noncolloidal. Various grades and phosphate ore concentrations were chosen for this rheological investigation. We created some experimental protocols to determine the main characteristics of these complex fluids and established relevant rheological models with a view to simulate the numerical flow in a cylindrical pipeline. Rheograms of these slurries were obtained using a rotational rheometer and were accurately modeled with commonly used yield-pseudoplastic models. The results show that the concentration of solids in a solid–liquid mixture could be increased while maintaining a desired apparent viscosity. Finally, the design equations for the laminar pipe flow of yield pseudoplastics were investigated to highlight the role of rheological studies in this context.

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Characterization of Food Packaging Films with Blackcurrant Fruit Waste as a Source of Antioxidant and Color Sensing Intelligent Material

Molecules ◽

10.3390/molecules26092569 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2569

Author(s):

Mia Kurek ◽

Nasreddine Benbettaieb ◽

Mario Ščetar ◽

Eliot Chaudy ◽

Maja Repajić ◽

...

Keyword(s):

Food Packaging ◽

Water Solubility ◽

Color Change ◽

Chitosan Film ◽

Water Vapor Permeability ◽

Vapor Permeability ◽

Color Changes ◽

Insoluble Particles ◽

Polymer Stability ◽

Food Packaging Films

Chitosan and pectin films were enriched with blackcurrant pomace powder (10 and 20% (w/w)), as bio-based material, to minimize food production losses and to increase the functional properties of produced films aimed at food coatings and wrappers. Water vapor permeability of active films increased up to 25%, moisture content for 27% in pectin-based ones, but water solubility was not significantly modified. Mechanical properties (tensile strength, elongation at break and Young’s modulus) were mainly decreased due to the residual insoluble particles present in blackcurrant waste. FTIR analysis showed no significant changes between the film samples. The degradation temperatures, determined by DSC, were reduced by 18 °C for chitosan-based samples and of 32 °C lower for the pectin-based samples with blackcurrant powder, indicating a disturbance in polymer stability. The antioxidant activity of active films was increased up to 30-fold. Lightness and redness of dry films significantly changed depending on the polymer type. Significant color changes, especially in chitosan film formulations, were observed after exposure to different pH buffers. This effect is further explored in formulations that were used as color change indicators for intelligent biopackaging.

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Performance and corrosion resistance mechanism of SA-Al composite hydrophobic coating on electrolytic manganese surface

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2021.127290 ◽

2021 ◽

pp. 127290

Author(s):

Sihua Lei ◽

Shuai Wang ◽

Hong Zhong ◽

Xin Ma ◽

Zhan-fang Cao

Keyword(s):

Corrosion Resistance ◽

Resistance Mechanism ◽

Hydrophobic Coating ◽

Al Composite ◽

Electrolytic Manganese

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Towards a methodology for the characterisation of the fabric of wet clays using X-ray scattering

E3S Web of Conferences ◽

10.1051/e3sconf/20199201005 ◽

2019 ◽

Vol 92 ◽

pp. 01005

Author(s):

Georgios Birmpilis ◽

Reza Ahmadi-Naghadeh ◽

Jelke Dijkstra

Keyword(s):

Materials Science ◽

Measurement Techniques ◽

Invasive Technique ◽

Colloidal Systems ◽

Characteristic Distance ◽

X Ray ◽

Hydrophobic Coating ◽

X Ray Scattering ◽

Wide Range ◽

Ray Scattering

X-ray scattering is a promising non-invasive technique to study evolving nano- and micromechanics in clays. This study discusses the experimental considerations and a successful method to enable X-ray scattering to study clay samples at two extreme stages of consolidation. It is shown that the proposed sample environment comprising flat capillaries with a hydrophobic coating can be used for a wide range of voids ratios ranging from a clay suspension to consolidated clay samples, that are cut from larger specimens of reconstituted or natural clay. The initial X-ray scattering results using a laboratory instrument indicate that valuable information on, in principal evolving, clay fabric can be measured. Features such as characteristic distance between structural units and particle orientations are obtained for a slurry and a consolidated sample of kaolinite. Combined with other promising measurement techniques from Materials Science the proposed method will help advance the contemporary understanding on the behaviour of dense colloidal systems of clay, as it does not require detrimental sample preparation

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Constituent elements of insoluble and non-volatile particles during the Last Glacial Maximum exhibited in the Dome Fuji (Antarctica) ice core

Journal of Glaciology ◽

10.3189/002214309788816696 ◽

2009 ◽

Vol 55 (191) ◽

pp. 552-562 ◽

Cited By ~ 17

Author(s):

Yoshinori Iizuka ◽

Takayuki Miyake ◽

Motohiro Hirabayashi ◽

Toshitaka Suzuki ◽

Sumito Matoba ◽

...

Keyword(s):

Last Glacial Maximum ◽

Calcium Ion ◽

Ice Core ◽

Ice Cores ◽

Glacial Maximum ◽

Ion Concentrations ◽

Last Glacial ◽

Insoluble Particles ◽

Almost All ◽

Constituent Elements

AbstractIn order to find environmental signals based on the dust and calcium-ion concentrations in ice cores, we determine the constituent elements of residue particles obtained after melting ice samples. We have designed a sublimating system that operates at −45°C, below the eutectic temperatures of major salts. This system permits us to obtain a great many non-volatile particles. After studying the non-volatile particles, we immersed them in water to remove soluble particles and compounds. We thereby analyzed a total of 1272 residue particles (from the melted sample), 2418 non-volatile particles (after sublimation) and 1463 insoluble particles taken from five sections of Last Glacial Maximum ice from the Dome Fuji (Antarctica) ice core. Their constituent elements were determined by scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM-EDS) and compared to the dust, calcium-ion and sodium-ion concentrations measured by ion chromatography. Our results indicate that >99.9% of the insoluble particles contain silicon but no sulfur, nitrogen or chlorine. A significant number of the non-volatile particles, however, contain sulfur and chlorine. We conclude that insoluble dust consists mostly of silicate, that almost all calcium ions originate from calcium sulfate and that almost all sodium ions originate from sodium sulfate and sodium chloride.

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Stone sustainable protection and preservation using a zein-based hydrophobic coating

Progress in Organic Coatings ◽

10.1016/j.porgcoat.2021.106434 ◽

2021 ◽

Vol 159 ◽

pp. 106434

Author(s):

Margherita Zucchelli ◽

Giulia Mazzon ◽

Laura Bertolacci ◽

Riccardo Carzino ◽

Elisabetta Zendri ◽

...

Keyword(s):

Hydrophobic Coating ◽

Sustainable Protection

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