Dispersion of Fe3O4 suspensions using sodium dodecylbenzene sulphonate as dispersant

Dispersion of Fe3O4–water suspension is enhanced with appropriate decision of solution pH and the amount of dispersant, sodium dodecylbenzene sulphonate. Active adsorption of dispersant onto Fe3O4 takes place only at pH levels below the isoelectric point. The median diameter is reduced with an increase in the adsorption amount of dispersant at first, and then it increases remarkably with higher adsorption. Change in Fe3O4 particle size according to the adsorption amount of dispersant is explained on the basis of contact angle measurements which relate to hydrophobicity or hydrophilicity of Fe3O4 particles.