scholarly journals Use of Ionic Liquids in Solid-Liquid Separation Processes

10.5772/65890 ◽  
2017 ◽  
Author(s):  
Lavinia Lupa ◽  
Petru Negrea ◽  
Adriana Popa
Keyword(s):  
Ionic Liquids ◽  
Liquid Separation ◽  
Separation Processes ◽  
Solid Liquid ◽  
Solid Liquid Separation

Obtaining Constitutive Equations for Thickening and Filtration Non-Newtonian Fluids

2014 ◽  
Vol 802 ◽  
pp. 274-279 ◽  
Author(s):  
Helio de Oliveira ◽  
Bruno Arantes Moreira ◽  
João Jorge Ribeiro Damasceno ◽  
Fabio de Oliveira Arouca
Keyword(s):  
Constitutive Equations ◽  
Xanthan Gum ◽  
Sediment Concentration ◽  
Particulate Material ◽  
Newtonian Fluids ◽  
Liquid Separation ◽  
Separation Processes ◽  
Medium Permeability ◽  
Solid Liquid ◽  
Solid Liquid Separation

The study of filtration and thickening of particulate systems are used in many industrial processes involving processes of solid-liquid separation, such as in sedimentation ponds, filters, the drilling of oil wells, among others. This paper aims to advance the empirical mechanisms involved in the processes of solid-liquid separation and obtain constitutive equations relating the pressure in solids and porous media permeability from non-Newtonian fluids. In the experiments used aqueous solutions of xanthan gum concentration of 0.1% in weight basis in order to ensure non-newtonian means. For the preparation of suspensions, was used calcium carbonate as particulate material in the separation process involved an initial concentration of 12% by volume. The concentrated sediment was maintained between 30 and 48% by volume. Settling tests were carried to term and sediments resulting from each test were evaluated by making use of the Gamma Rays Attenuation Technique (GRAT). The results show that GRAT is effective in determining sediment concentration distributions formed from non-Newtonian solutions, allowing the constitutive equations to obtain pressure and the solid porous medium permeability, very important for simulations of solid-liquid separation processes.

scholarly journals From colloidal dispersions to colloidal pastes through solid-liquid separation processes

2005 ◽  
Vol 77 (8) ◽  
pp. 1369-1394 ◽  
Author(s):  
J. B. Madeline ◽  
M. Meireles ◽  
J. Persello ◽  
C. Martin ◽  
R. Botet ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Volume Fraction ◽  
Cell Model ◽  
Solid Particles ◽  
Fractal Structures ◽  
Particle Volume ◽  
Liquid Separation ◽  
Separation Processes ◽  
Solid Liquid ◽  
Solid Liquid Separation

Solid-liquid separation is an operation that starts with a dispersion of solid particles in a liquid and removes some of the liquid from the particles, producing a concentrated solid paste and a clean liquid phase. It is similar to thermodynamic processes where pressure is applied to a system in order to reduce its volume. In dispersions, the resistance to this osmotic compression depends on interactions between the dispersed particles.The first part of this work deals with dispersions of repelling particles, which are either silica nanoparticles or synthetic clay platelets, dispersed in aqueous solutions. In these conditions, each particle is surrounded by an ionic layer, which repels other ionic layers. This results in a structure with strong short-range order. At high particle volume fractions, the overlap of ionic layers generates large osmotic pressures; these pressures may be calculated, through the cell model, as the cost of reducing the volume of each cell. The variation of osmotic pressure with volume fraction is the equation of state of the dispersion. The second part of this work deals with dispersions of aggregated particles, which are silica nanoparticles, dispersed in water and flocculated by multivalent cations. This produces large bushy aggregates, with fractal structures that are maintained through interparticle surface-surface bonds. As the paste is submitted to osmotic pressures, small relative displacements of the aggregated particles lead to structural collapse. The final structure is made of a dense skeleton immersed in a nearly homogeneous matrix of aggregated particles. The variation of osmotic resistance with volume fraction is the compression law of the paste; it may be calculated through a numerical model that takes into account the noncentral interparticle forces. According to this model, the response of aggregated pastes to applied stress may be controlled through the manipulation of interparticle adhesion.

The Role of Colloid Interactions in Solid-Liquid Separation

1993 ◽  
Vol 27 (10) ◽  
pp. 1-17 ◽  
Author(s):  
John Gregory
Keyword(s):  
Particle Size ◽  
Fine Particles ◽  
Major Effect ◽  
Liquid Separation ◽  
Separation Processes ◽  
Polymer Bridging ◽  
Colloid Interactions ◽  
External Forces ◽  
Solid Liquid ◽  
Solid Liquid Separation

Forces between particles in water become especially important when the particles are in the colloidal size range (less than a few mm). To a first approximation inter-particle forces or colloid interactions are linearly dependent on particle size and they become stronger, relative to external forces, as particle size decreases. The separation of fine particles from water by processes such as coagulation, filtration and flotation can be crucially dependent on the manipulation of colloid interactions, usually to promote attachment of particles to each other or to surfaces. The most important types of colloid interaction are briefly discussed. These include van der Waals forces, electrical interaction, hydration forces, hydrophobic interaction and effects associated with adsorbed polymers, such as steric repulsion and polymer bridging. These are all short-range interactions, which have little influence on the transport of particles but which can have a major effect on collision efficiencies and on the adhesion between particles. Some examples of solid-liquid separation processes in which colloid interactions are important are given.

Sign in / Sign up

Export Citation Format

Share Document