Adsorção de tensoativos em resina trocadora de cations

AUTOR(ES)

Efigenia Amorim

DATA DE PUBLICAÇÃO

1995

RESUMO

A tensiometric detector based on surface tension measurement by the drop-weight method (TSDMG) was built and fitted in a standard liquid chromatograph (together with an UV photometric detector) to monitor surfactants in a liquid flow by dynamic surface tension (gd) measurements. The gd values obtained for aqueous solutions of polyethylene glycol mono [p-1,1,3,3-tetramethyl-butyl) phenyl] ether (Triton X-100) showed good agreement with literature data obtained by pendant drop tensiometry, enhanced by videoimage digitalization. This apparatus was used to measure dynamic adsorption of the cationic surfactant, cetylpyridinium chloride (CPC) in a sulfonated polystyrene ionexchanger (Lewatit S-100). Aqueous solutions of CPC (0,70 mM) exhibit q values around 10 for short contact periods (approximately 100 seconds) with the resin at 26±2°C. The sorption kinetics was also determined by the static method (batch). At higher concentrations (2,0 and 4,0 mM) and temperatures (45°C) the cation exchange site occupancy (q) approaches unity after 20-30 hours. q versus time curves are not smooth and show some points with abrupt changes of surfactant sorption. Microscopic examination showed that the resin particles swell and break down during surfactant sorption, evidencing that the mechanical tensions produced in this process are large enough to induce fracture in highly crosslinked and poorly plasticized particles. The adsorption of aqueous solutions of other, isolated or mixed surfactants (Triton X-100 and sodium dodecylsulphate) on the same resin was also measured by the dynamic method. The on-line TSDMG method developed in this work is effective, fast and accurate for the determination of dynamic adsorption of isolated of mixed surfactants. However the application of this tensiometric method is restricted to surfactant concentration ranges below c.m.c.

ASSUNTO(S)

cations adsorção resinas detectores quimicos

Documentos Relacionados

• Adsorção de insulina em resina trocadora de ion utilizando leitos fixos e fluidizados
• Adsorção de beta-galactosidase de Scopulariopsis sp. em resina trocadora de ions objetivando a purificação e a ampliação de escala
• Estudo da adsorção de tensoativos aniônicos sulfonados em hidróxidos duplos lamelares
• Estudo da adsorção de brometo de etídeo em resina XAD-7
• Modificações nas formas de fósforo do solo após extrações sucessivas com Mehlich-1, Mehlich-3 e resina trocadora de ânions