scholarly journals Effect of Particle Specific Surface Area on the Rheology of Non-Brownian Silica Suspensions

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4628
Author(s):  
Anastasia Papadopoulou ◽  
Jurriaan J. J. Gillissen ◽  
Manish K. Tiwari ◽  
Stavroula Balabani
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Particle Surface ◽  
Shear Thinning ◽  
Glass Sphere ◽  
Suspension Rheology ◽  
Particle Suspensions ◽  
Frictional Contacts ◽  
Aqueous Solvent

Industrial formulations very often involve particles with a broad range of surface characteristics and size distributions. Particle surface asperities (roughness) and porosity increase particle specific surface area and significantly alter suspension rheology, which can be detrimental to the quality of the end product. We examine the rheological properties of two types of non-Brownian, commercial precipitated silicas, with varying specific surface area, namely PS52 and PS226, suspended in a non-aqueous solvent, glycerol, and compare them against those of glass sphere suspensions (GS2) with a similar size distribution. A non-monotonic effect of the specific surface area (S) on suspension rheology is observed, whereby PS52 particles in glycerol are found to exhibit strong shear thinning response, whereas such response is suppressed for glass sphere and PS226 particle suspensions. This behaviour is attributed to the competing mechanisms of particle–particle and particle–solvent interactions. In particular, increasing the specific surface area beyond a certain value results in the repulsive interparticle hydration forces (solvation forces) induced by glycerol overcoming particle frictional contacts and suppressing shear thinning; this is evidenced by the response of the highest specific surface area particles PS226. The study demonstrates the potential of using particle specific surface area as a means to tune the rheology of non-Brownian silica particle suspensions.

Adsorption of Sodium Dodecyl Sulfate on Natural Rubber Latex Particles and Determination of Specific Surface Area of the Particles

1981 ◽  
Vol 54 (1) ◽  
pp. 124-133 ◽  
Author(s):  
S. F. Chen
Keyword(s):  
Particle Size ◽  
Fatty Acid ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sodium Dodecyl ◽  
Particle Surface ◽  
Molecular Area ◽  
Latex Particles

Abstract Soap titration of polymer latex is a widely used method for the determination of the specific surface area and particle size in synthetic latices. The method involves the titration of a latex of known polymer and soap content with a standard soap solution until the critical micelle concentration (CMC) is reached. At this concentration, saturation adsorption of the soap to form a monolayer on the particle surface occurs. From a knowledge of the amount and kind of soap adsorbed and the effective molecular area of the soap on the surface, the specific surface area and average diameter of the particles can be calculated. The effective molecular area of soap at saturation adsorption on polymer particle surface has been determined by comparing adsorption data with particle size data obtained by electron microscopy. Little information is available on the adsorption of sodium dodecyl sulfate (SDS) on NR latex particles. In ammoniated latex, these particles are covered by a complex mixture of proteins, fatty acid soaps, and lipids, the composition and concentration of which are not known accurately. Cockbain modified the soap titration method of determining particle sizes in synthetic latices and claimed that it was applicable to NR latices. In this method SDS was titrated to the latex adjusted to pH 6 ± 0.2. It was assumed that at this pH the interfacial activity of SDS was high while that of the proteins and fatty acid soaps initially present on the latex particles was comparatively low. Under these conditions the SDS would displace almost all the proteins and fatty acid soaps on the particles when sufficient SDS has been added to form micelles in the aqueous phase. The specific surface area was calculated from the SDS adsorption after assuming the molecular adsorption area of SDS to be 60 A˚. No account was taken of the effect of the poly(vinyl alcohol) creaming agent on adsorption. Sekhar found that Cockbain's method of soap titration was temperature dependent. Van den Tempel has shown that electron microscopy cannot yield accurate specific surface area of NR latex particles because of the heterogeneous particle size distribution inherent in unconcentrated latex.

scholarly journals Experimental Study on Influence of Al2O3, CaO and SiO2 on Preparation of Zinc Ferrite

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 396
Author(s):  
Jinlin Yang ◽  
Shuo Xu ◽  
Wentao Zhou ◽  
Pengyan Zhu ◽  
Jiguang Liu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Pore Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Zinc Ferrite ◽  
Particle Surface ◽  
Molar Ratio ◽  
Size Analysis ◽  
Sulfide Deposit ◽  
Pore Size Analysis

Gossan ore of sulfide zinc deposit contains abundant zinc, iron, and other metal elements, which is a significant resource with complex components and can be utilized. In this study, a new technology of preparing zinc ferrite from zinc sulfide deposit gossan was proposed. The effects of Al2O3, CaO, and SiO2 in gossan on the formation of zinc ferrite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and specific surface area and pore size analysis (BET). The results show that the presence of Al2O3 and CaO could hinder the formation of zinc ferrite, while silica had no effect on the formation of zinc ferrite. Under the conditions of the molar ratio of ZnO and Fe2O3 to Al2O3, CaO, and SiO2 of 1:1:1, an activation time of 60 min, and a roasting temperature of 750 °C for 120 min, the products, which had good crystallinity, smooth particle surface, and uniform particle size could be obtained. In addition, compared to the roasted products with Al2O3 and CaO, the specific surface area, pore volume, and pore size of the products with SiO2 were the largest.

Fuels Desulphurisation by Adsorbtion on Fe / Bentonite

2017 ◽  
Vol 68 (3) ◽  
pp. 483-486
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Dorin Bombos
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Adsorption Process ◽  
Continuous System ◽  
Gas Oil ◽  
Average Pore ◽  
Atmospheric Distillation

Desulfurisation of atmospheric distillation gasoline and gas oil was performed by adsorption process on Fe/ bentonite. The adsorbent was characterized by determining the adsorption isotherms, specific surface area, pore volume and average pore diameter. Adsorption experiments of atmospheric distillation gasoline and gas oil were performed in continuous system at 280�320oC, 5 atm and volume hourly space velocities of 1�2 h-1. The efficiency of adsorption on Fe / bentonite was better at desulphurisation of gasoline versus gas oil.

scholarly journals Nanoporous Quasi-High-Entropy Alloy Microspheres

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 345 ◽  
Author(s):  
Lianzan Yang ◽  
Yongyan Li ◽  
Zhifeng Wang ◽  
Weimin Zhao ◽  
Chunling Qin
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Specific Surface Area ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Hierarchical Porous

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.

Sign in / Sign up

Export Citation Format

Share Document