Studies on Surfactant Adsorption at the Cellulose-Water Interface

Abstract

The adsorption of anionic - sodium dodecylbenzenesulfonate (NaDBS), cationic – cetyl trimethyl ammonium bromide (CTAB) and nonionic - Triton X-100 (TX-100) surfactants under different conditions on cellulose-water interface are investigated and the adsorption results are compared with detergency of particulate and composite soil. The kinetics of adsorption of different surfactants on cellulose-water interface show that a cationic surfactant adsorbs rapidly and nonionic and anionic surfactants adsorb relatively slowly. The equilibrium time for cationic surfactant is less (~ 10 min) but higher for the anionic and nonionic surfactants (~ 1 hr). The cellulosic surface is shown to have dual sites of hydrophobic and hydrophilic in nature. It is shown that anionic and nonionic surfactant molecules mostly adsorb on the hydrophobic site, while cationic surfactant molecules mostly adsorb on the hydrophilic site. Anionic surfactant molecules in presence of salt adsorb onto both hydrophobic and ...