Question

In: Civil Engineering

discuss and describe the particle electrical charge theory with emphasis on electrical double layer theory and...

discuss and describe the particle electrical charge theory with emphasis on electrical double layer theory and its significance during the design of water treatment coagulation unit?

Solutions

Expert Solution

Electrical Double Layer

Although individual hydrophobic colloids have an electrical charge, a colloidal dispersion does not have a net electrical charge. The diffuse layer in a colloidal dispersion contains a quantity of counter ions sufficient to balance the electrical charge on the particle. The charge distribution in the diffuse layer of a negatively charged colloid can be represented by the curve ABCD in the figure. The ions involved in this electroneutrality are arranged in such a way as to constitute what is called the electrical double layer.

Net repulsion force, which may be considered as energy barrier must be overcome before aggregation occurs. The magnitude of energy barrier depends on (1) charge on the particle, and (2) ionic composition of water.

Destabilization of Colloidal Dispersion

Particle destabilization can be achieved by four mechanisms:

  • Change characteristics of medium-Compression of the double layer.

  • Change characteristics of colloid particles-Adsorption and charge neutralization.

  • Provide bridges-
    1. Enmeshment in a precipitate.
    2. Adsorption and interparticle bridging.

Related Solutions

Describe what is meant by an electrical double layer (EDL) that occurs at the interface between...
Describe what is meant by an electrical double layer (EDL) that occurs at the interface between an electrode and the solution
1. The adsorbed ions comprising the Stern layer around a charged particle have the same charge...
1. The adsorbed ions comprising the Stern layer around a charged particle have the same charge (positive or negative) as the particle itself. True. False, they have the opposite charge. False, there are an equal number of positively and negatively charged ions in the Stern layer. 2. Both ionic and nonionic surfactants can stabilize colloidal dispersions by adsorbing onto particle surfaces. True. False, nonionic surfactants do not adsorb on particle surfaces. False, surfactant adsorption always destabilizes colloidal dispersions by reducing...
Describe the nature of colloidal precipitate particles. (describe the electric double layer) ,Why do they tend...
Describe the nature of colloidal precipitate particles. (describe the electric double layer) ,Why do they tend to not settle, and What factors control coagulation of a colloidal particles?
In the figure particle 1 of charge q1 = 0.93 μC and particle 2 of charge...
In the figure particle 1 of charge q1 = 0.93 μC and particle 2 of charge q2 = -2.96 μC, are held at separation L = 9.5 cm on an x axis. If particle 3 of unknown charge q3 is to be located such that the net electrostatic force on it from particles 1 and 2 is zero, what must be the (a)x and (b)y coordinates of particle 3?
Particle A of charge 3.25 ✕ 10−4 C is at the origin, particle B of charge...
Particle A of charge 3.25 ✕ 10−4 C is at the origin, particle B of charge −6.20 ✕ 10−4 C is at (3.98 m, 0) and particle C of charge 1.25 ✕ 10−4 C is at (0, 3.38 m). (a) What is the x-component of the electric force exerted by A on C? N (b) What is the y-component of the force exerted by A on C? N (c) Find the magnitude of the force exerted by B on C....
Particle A of charge 3.25 ✕ 10−4 C is at the origin, particle B of charge...
Particle A of charge 3.25 ✕ 10−4 C is at the origin, particle B of charge −6.20 ✕ 10−4 C is at (3.98 m, 0) and particle C of charge 1.25 ✕ 10−4 C is at (0, 3.38 m). (e) Calculate the y-component of the force exerted by B on C. N (f) Sum the two x-components to obtain the resultant x-component of the electric force acting on C. N (g) Repeat part (f) for the y-component. N (h) Find...
In the figure particle 1 of charge +q and particle 2 of charge +4q are held...
In the figure particle 1 of charge +q and particle 2 of charge +4q are held at separation L = 8.38 cm on an x axis. If particle 3 of charge q3 is to be located such that the three particles remain in place when released, what must be the (a) x and (b) y coordinates of particle 3 and (c) the ratio q3/q?
Discuss the similarities and the differences between the electrical force on a charge and magnetic field...
Discuss the similarities and the differences between the electrical force on a charge and magnetic field force on a charge. Please make a short and simple answer.
Particle A of charge 2.97 10-4 C is at the origin, particle B of charge -5.58...
Particle A of charge 2.97 10-4 C is at the origin, particle B of charge -5.58 10-4 C is at (4.00 m, 0), and particle C of charge 1.10 10-4 C is at (0, 3.00 m). We wish to find the net electric force on C. (a) What is the x component of the electric force exerted by A on C? N (b) What is the y component of the force exerted by A on C? N (c) Find the...
Particle 1 of charge q1 = 0.96 μC and particle 2 of charge q2 = -3.02...
Particle 1 of charge q1 = 0.96 μC and particle 2 of charge q2 = -3.02 μC, are held at separation L = 10.6 cm on an x axis. If particle 3 of unknown charge q3 is to be located such that the net electrostatic force on it from particles 1 and 2 is zero, what must be the x coordinate of particle 3?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT