What is ionic layer compression?

Concept. Ionic layer compression: A high ion concentration compresses the layer composed of –ve charged ions towards the surface of the colloid. Once sufficient compression has occurred, Vander wall force of attraction will be predominant and thus particles grow in size and will be removed in a sedimentation tank.

What is ionic layer?

The zero ionic layer is an ionic domain within the otherwise largely hydrophobic alpha-helical complex (SNARE complex) . It is stabilized by attractive forces(dipole-dipole interactions) between three partially negatively charged carbonyl groups of glutamine residues and a positively charged arginine.

What is double layer compression in coagulation?

Double layer compression: This can be accomplished by addition of an indifferent electrolyte (charged ions with no specific attraction for colloid primary surface). As the counter-ions are pushed closer to the surface the repulsion forces becomes easier to negate by van der Waals forces.

What is interparticle bridging?

Interparticle bridging 33 Destabilization of Colloids — Continued Natural Organic polymers(e.g., starch, cellulose) Synthetic organic polymeric compounds – They have large molecular size – They may be anionic, cationic or non-ionic Polymer molecule become attached to a colloidal particle at one or more sites due to …

What is gold no in chemistry?

The Gold Number is the minimum weight (in milligrams) of a protective colloid required to prevent the coagulation of 10 ml of a standard hydro gold sol when 1 ml of a 10\% sodium chloride solution is added to it. It was first used by Richard Adolf Zsigmondy.

What is sweep coagulation?

Sweep Coagulation: Al (OH)3 is formed when alum is added to water, is a shapeless and sticky precipitate in nature. These are heavier than water and settles down by gravity. This process is called sweep coagulation. If alum is added in water, then it will form Al+3 and SO42-.

What is the difference between coagulation and flocculation?

Coagulation: Particles that aggregate with themselves e.g. by the influence of a change in pH. Flocculation: Particles that aggregate by the use of polymers that binds them together.

What are the four mechanisms of coagulation?

There are four main mechanisms for coagulation: double layer compression, adsorption and charge neutralization, sweep flocculation, and inter-particle bridging.

Is Tyndall A effect?

Tyndall effect, also called Tyndall phenomenon, scattering of a beam of light by a medium containing small suspended particles—e.g., smoke or dust in a room, which makes visible a light beam entering a window. The effect is named for the 19th-century British physicist John Tyndall, who first studied it extensively.

What is Peptization 12th?

Peptization is the process of formation of colloidal sol in which conversion of fresh precipitate into colloidal particles by shaking it with the dispersion medium with the help of a small amount of suitable electrolyte. The electrolyte which is added is called a peptizing agent. This gives particles of colloidal size.

What is Jar testing?

A laboratory procedure that simulates coagulation/flocculation with differing chemical doses. The purpose of the procedure is to estimate the minimum coagulant dose required to achieve certain water quality goals. Samples of water to be treated are placed in six jars.

What is the ionic double layer?

The compact (fixed) inner layer and the more diffuse outer layer are known as the ionic double layer. The problem with colloids is that they are difficult to remove by conventional means because of their size. Naturally, it follows that by getting them to flocculate (stick together), they will settle faster or filter easier.

What is flocculation and how does it work?

Flocculation is a process by which a chemical coagulant added to the water acts to facilitate bonding between particles, creating larger aggregates which are easier to separate. The method is widely used in water treatment plants and can also be applied to sample processing for monitoring applications.

What is meant by flocculation of pigment?

Flocculation of pigment means that the effective particle size of the TiO 2 is increased and longer wavelengths of light will be preferentially scattered. Pigment distribution in dried films can be observed directly by SEM.

What is the purpose of formation of flocs?

The formation of flocs aids in improved settling rates, better overhead clarity and/or faster filtration rates. There are three main methods for achieving aggregation of very small or colloidal particles in suspension: