solid particles in a suspension possess charge in relation to their surrounding liquidmedium. Solid particles may become charged through different ways. If the suspension contains electrolytes, selective adsorption of a particular ionic species by thesolid particles is a possibility. This will lead to the formation of charged particles.For example, in case of a dispersion of rubber particles in water, it may happen thathydroxyl ions (OH−) will be more adsorbed than hydronium ions (H3O+) due to theasymmetric nature of the hydroxyl ion (Tabibi and Rhodes 1996). Occasionally,the surface active agents, which are already adsorbed at the solid–liquid interface,may ionize to give the particles positive or negative charge. Sodium dodecyl sulfate(SDS), for example, is anionic in aqueous medium. Solid particles can also be chargedby ionization of functional group of the particles. In this case, the total charge is afunction of the pH of the surrounding vehicle. Peptide and protein molecules containionizable groups, such as –COOH and –NH2. Dispersed particles of these types ofmolecules will ionize. The sign and magnitude of the ionization mostly depend onthe pH of the surrounding vehicle. to their surrounding liquid mediumsolid particles in a suspension possess charge in relation to their surrounding liquidmedium charged through different ways
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