Structural effects on the interactions of benzene and naphthalene sulfonates with activated carbon cloth during adsorption from aqueous solutions

Interactions of benzene and naphthalene sulfonates with activated carbon cloth (ACC) during adsorption from aqueous solutions were investigated. Systematically chosen sulfonates were sodium salt of benzene sulfonic acid (NaBS), disodium salt of 1,3-benzene disulfonic acid (Na2BDS), sodium salt of 1-naphthalene sulfonic acid (NaNS), disodium salt of 1,5-naphthalene disulfonic acid (Na2NDS) and trisodium salt of 1,3,(6 or 7)-naphthalene trisulfonic acid (Na3NTS). The adsorption behaviors of these adsorbates from solutions in water and in 0.01 M H2SO4 onto the ACC were monitored by in-situ UV–visible spectroscopic technique. The order of rates and extents of adsorption of sulfonates were explained in terms of acidity of the medium and structural factors influencing the interactions between sulfonates and the ACC surface. Kinetic data of adsorption were treated according to pseudo first-order, pseudo second-order, Elovich and intra-particle diffusion models. The best model representing the experimental kinetic data was found to be the pseudo second-order model. Adsorption isotherms of the sulfonates onto the ACC were derived at 30 °C. Isotherm data were found to fit the Freundlich model better than the Langmuir model.