Adsorption Study of Cationic Surfactants in Presence of Dyes on the Cotton/Water Interface

Abstract

The adsorption study of surfactant/dye mixed systems on natural fibres is important
because these bioactive systems used in dyeing processes may reach surface waters and have
a consistent impact upon health. The contamination of soil and surface water with the strongly
active organic compounds (surfactants and dyes) was recognized as an important problem in
the last years.
By UV-VIS spectrophotometry and surface tension measurements the formation of
colloidal associates between cationic surfactants and dyes used for dyeing of fibres was put in
evidence. A clear difference between the adsorbent system in the case of monomer surfactant
and the adsorbent system in the presence of the dye in solution was found by calculating the
surface occupied by surfactant molecules on the cotton/water interface. The type of interaction
and the organization mode of surfactant-dye complexes on the cotton/water interface were
established by treating the original data using classical and recent equations of adsorption
isotherms (Fowler-Guggenheim, Langmuir)