Alcohol dehydrogenase on inorganic powders: Zeta potential and particle agglomeration as main factors determining activity during immobilization

The way to successfully upgrade a phosphate ore is based on the full understanding of its mineralogy, minerals surface properties, minerals distribution and liberation. The conception of a treatment process consists of choosing the proper operations with an adequate succession depending on the ore properties. Usually, froth flotation takes place in phosphate enrichment processes, since it is cheap, convenient, and well developed. Nevertheless, it is a complex technique as it depends on the mineral’s superficial properties in aqueous solutions. Aspects such as wettability, surface charge, zeta potential, and the solubility of minerals play a basic role in defining the flotation conditions. These aspects range from the reagents type and dosage to the pH of the pulp. Other variables namely particles size, froth stability, and bubbles size play critical roles during the treatment, as well. The overall aim is to control the selectivity and recovery of the process. The following review is an attempt to add to previous works gathering phosphate froth flotation data. In that sense, the relevant parameters of phosphate ores flotation are discussed while focusing on apatite, calcite, dolomite, and quartz as main constituent minerals.

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Studies of Some Properties and the Structure of Polyethylene Glycol (PEG) Macromolecules Adsorbed on a TiO2 Surface

Adsorption Science & Technology ◽

10.1260/0263617011494268 ◽

2001 ◽

Vol 19 (5) ◽

pp. 397-407 ◽

Cited By ~ 14

Author(s):

S. Chibowski ◽

M. Paszkiewicz

Keyword(s):

Molecular Weight ◽

Polyethylene Glycol ◽

Zeta Potential ◽

Surface Charge ◽

Adsorption Layer ◽

Bulk Solution ◽

Ionic Structure ◽

Solution Interface ◽

Main Factors ◽

Presence And Absence

In the studies presented, the influence of the molecular weight of polyethylene glycol (PEG) on the adsorption and electrical properties at the metal oxide/polymer solution interface has been determined. The main factors responsible for the observed changes in the zeta potential and surface charge of titania were determined on the basis of the data obtained. It was demonstrated that changes in the ionic structure of the Stern layer depend on the molecular weight of PEG and its conformation. A possible mechanism for the changes in zeta potential both with pH and molecular weight was proposed on the basis of values of the surface charge difference (Δσ0) and the diffuse layer charge difference (Δσd) as determined in the presence and absence of the polymer. The thickness of the adsorption layer (δ) on the surface of titania was calculated from the zeta potential changes, both in the presence and absence of the polymer. A distinct influence of the PEG molecular weight was noted on the values of the adsorption layer thickness (δ) determined. The structures of the macromolecules in solution and at the solid/solution interface were compared and from the dependencies obtained some changes in the shape and dimensions of the polymer coils on passing from the bulk solution to the interface were proposed.

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Zeta potential of a subbituminous coal and its effect on particle agglomeration

Mining Metallurgy & Exploration ◽

10.1007/bf03402714 ◽

1996 ◽

Vol 13 (1) ◽

pp. 31-35 ◽

Cited By ~ 1

Author(s):

Y. Lin ◽

H. Liu

Keyword(s):

Zeta Potential ◽

Particle Agglomeration

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Optimization of the NDV-N-2-HACC/CMC Microspheres Preparation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.804.85 ◽

2013 ◽

Vol 804 ◽

pp. 85-88

Author(s):

Qian Chen ◽

Hong Kang ◽

Yang Zhang ◽

Hao Wu ◽

Chun Xiao Dai ◽

...

Keyword(s):

Particle Size ◽

Zeta Potential ◽

Encapsulation Efficiency ◽

Entrapment Efficiency ◽

Factorization Method ◽

Optimal Conditions ◽

Orthogonal Factorization ◽

Main Factors ◽

Average Size

Purpose:in this study, the conditions of the preparation of NDV-N-2-HACC/CMC microspheres are optimized. Methods:Using entrapment efficiency, particle size, Zeta potential as the evaluating indicators, 3 main factors to influence the preparation for microspheres were optimized by orthogonal factorization method. Result:The optimal conditions were 1.0 mg/ml HACC, 1.2 mg/ml CMC, 1:3 (v/v) NDV/HACC, and 1200 r/min and 30 min for stirring. The range of particle size was 192.1-595.2 nm, and average size was 304.3 nm. Zeta potential was +32.50 mV; encapsulation efficiency (EE) was (98.96±2.1) %.Conclusion:the conditions of the preparation of NDV-N-2-HACC/CMC microspheres are optimized.

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Slurry Particle Agglomeration Model for Chemical Mechanical Planarization (CMP)

MRS Proceedings ◽

10.1557/proc-1249-e04-03 ◽

2010 ◽

Vol 1249 ◽

Cited By ~ 4

Author(s):

Joy Marie Johnson ◽

Duane Boning

Keyword(s):

Zeta Potential ◽

Interaction Potential ◽

Electrostatic Interactions ◽

Aqueous Electrolyte ◽

Chemical Mechanical Planarization ◽

Particle Agglomeration ◽

Final Particle ◽

Abrasive Particles ◽

Proposed Model ◽

Slurry Composition

AbstractIn this work we propose a particle agglomeration model for chemical mechanical planarization (CMP) under the primary motivation of understanding the creation and behavior of the agglomerated slurry abrasive particles during the CMP process, which are a major cause of defectivity and poor consumable utility due to sedimentation.The proposed model considers the slurry composition as a colloidal suspension of charged colloidal silica in an electrically neutral aqueous electrolyte. First, a theoretical relationship between the measurable chemical parameters of the slurry's aqueous electrolyte, the surface potential of the abrasive particles, and corresponding zeta potential between the agglomerated abrasive particles is presented. Secondly, this zeta potential is used in a modified DVLO interaction potential model to determine the particle interaction potentials due to both the attractive van Der Waals forces and repulsive electrostatic interactions. Finally, the total interaction potential created is then used to define a stability ratio for slow versus fast agglomeration and corresponding agglomeration rate equations between particles; these are used in a discrete population balance framework to describe the final particle size distribution with respect to time and agglomerate composition.The proposed model will provide both a qualitative and quantitative description of agglomeration of abrasive slurry particles during CMP that can be extended to account for slurry composition or abrasive particle type, enabling more accurate process control, increased consumable utility, and possible defectivity reduction.

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