Influence of some physicochemical parameters on the passive sampling of copper (II) from aqueous medium using a polymer inclusion membrane device.

ABSTRACT

Recently polymer inclusion membranes (PIMs) have been proposed as materials for passive sampling, nonetheless a theoretical base to describe the mass transfer process through those materials, under such conditions of monitoring, has not been elucidated. Under the assumption that (i) the transport of the metal ion occurs at steady state conditions, (ii) the concentration gradients are linear, and (iii) the kinetics of the chemical reactions in the extraction process on the membrane are elemental; an equation for the passive sampling of copper (II) using a PIM system containing Kelex-100 as carrier is derived. The prediction capacity of this sampler under different conditions of temperature, metal concentration, flow velocity, ionic strength and pH is analyzed as well. Among the dependencies of the PIM on the physicochemical conditions, effects of concentration, temperature and flow velocity tend to increment copper (II) flux across the membrane, being the parameter temperature the one with the most pronounced effect at T ≥ 30 °C. Ionic strength had no great effect on passive sampler response, however the sampler is dependent on the acidity of the medium. The comparable metal ion concentrations estimated from the PIM sampler to those obtained by direct measurements of the sampling medium suggest that PIMs can be robust materials when used as passive sampler devices.