A. Fachini, I. Joekes
Mar 5, 2002
Citations
1
Influential Citations
22
Citations
Journal
Colloids and Surfaces A: Physicochemical and Engineering Aspects
Abstract
Abstract Sodium dodecylbenzenesulfonate (SDBS) aqueous solutions in contact with chrysotile fibers show a concentration reduction up to 53% ( C 0 =3.0×10 −3 mol l −1 , above critical micellar concentration (CMC)) and 90% ( C 0 =0.15×10 −3 mol l −1 , below CMC) after 4 h contact with the fibers at room temperature, when air bubbling is used as an oxygen supplier. Adsorption/desorption experiments with 3.0×10 −3 mol l −1 solution show that only 6% of the surfactant is recovered after successive washing steps in water. Experiments in open and closed stirred flasks show that the surfactant depletion is lower. In non-aerated systems, pseudo-equilibrium is achieved after 4 h. When air bubbling is used, the amount of SDBS removed keeps rising at least for 24 h. The calculated Gibbs pseudo-surface concentration indicates the formation of 2–10 monolayers onto the chrysotile surface. These results are inconsistent with a solely adsorptive process. One degradation product was identified and quantified (CO 2 ), rendering a turnover number of 1500. A mechanism for a catalytic process is proposed.