Integrated removal of nonionic surfactant and cobalt(II) from plating rinse water

Cosorption of nonionic surfactant Lutensol AO-10 (oxyethylated higher fatty alcohols) and cobalt(II) by the hydrogen form of polyacrylic acid-functionalized cation exchanger Purolite C 106 has been investigated to establish the adequacy of this resin for the simultaneous removal of cobalt(II) and nonionic surfactant from plating rinse water prior to recycling. Kinetics of the sorption of AO-10, cobalt(II) and products of their interaction is controlled by the intraparticle diffusion in acidic (pH 5) and alkaline media (pH 8). With a decrease in the influent acidity from pH 5 to 8 the rate of intraparticle diffusion of AO-10 increases, although the equilibrium sorption decreases. The effect of cobalt(II) results in a decrease in the rate of intraparticle diffusion and equilibrium sorption of AO-10 at pH 5, although it leads to an increase in the corresponding parameters at pH 8. Unlike AO-10, the cobalt(II) equilibrium sorption increases on decreasing the influent acidity from pH 5 to 8. The effect of AO-10 results in an increase in the rate of the intraparticle diffusion and the equilibrium sorption of cobalt(II) at the two pH investigated. The performance of the column, packed with the hydrogen form of Purolite C 106, is better with respect to AO-10 than that with respect to cobalt(II). The effect of AO-10 promotes the removal of cobalt(II), whereas the effect of cobalt(II) interferes with the removal of AO-10. The hydrogen form of Purolite C 106 cation exchanger is suggested to be applicable for the simultaneous and, therefore, economic removal of nonionic surfactant and cobalt(II) from cobalt plating rinse water prior to recycling, preventing the environmental contamination.