Particulate soil detergency for hydrophobic particle removal: effects of surfactant and fabric types

Abstract

In this research, the effects of surfactant concentration, surfactant type, type of fabric, and solution pH on the detergency performance in hydrophobic particulate removal were investigated. Carbon black was selected as a model hydrophobic particulate and three types of fabric were used: pure polyester, pure cotton, and blended polyester-cotton. The detergency experiments of carbon black removal were carried out by using sodium dodecyl sulfate, an anionic surfactant, and octyl phenol ethoxylate, a nonionic surfactant. To gain a better understanding of the mechanisms of particulate soil detergency, the adsorption isotherms of surfactants, zeta potential, contact angle, and surface tension were studied. For any given type of surfactant, %detergency increased with in-creasing solution pH and the maximum performance was found at pH 11. In addition, SDS was found to exhibit a better detergency than Triton X-100 since the zeta potential on the carbon black surface in SDS solutions is more negative than those in Triton X-100 solutions. Although the surfactant adsorption density of polyester is lower than cot-ton, carbon black can be removed from polyester better than from cotton.