Determination of diffusion coefficients of hydrophobic extractants and their copper(II) complexes from dynamic adsorption measurements carried out in model extraction systems

Equilibrium and dynamic interfacial tensions measured at 20degreesC for 10(-5) M beta-diketo-1-phenyldecane-1,3-dione (I), 2-hydroxy-5-t-nonylacetophenone oxime (II), trioctylphosphine oxide (III), 2-hydroxy-5-t-octyl-acetophenone (IV) and -benzophenone (V), Cu(II) complexes (except for III), and equimolar I + II, were used in conjunction with the Ward-Tordai (J. Chem. Phys., 14,453 (1946)) adsorption model solved (V.B. Fainerman et at., Coll. Surf. A, 87, 61 (1994)) for time t --> 0 and t --> infinity, to evaluate diffusivities Dt --> 0, and Dt --> infinity, cm(2)/s. With toluene as organic phase, 10(6) x Dt --> 0 were: I, 1.61; II, 1.82; IV, 1.86; V, 3.05; and for Cu(II) complexes: 3.56, 2.24, 2.17, and 1.65, resp., whereas 10(8) x Dt --> infinity were: I, 2.65; II, 9.19; IV, 7.69; V, 4.33 and for Cu(II) complexes: 1.58, 31.5, 26.5, and 9.42, resp. With octane, 10(6) x Dt --> 0 were: I, 4.72; II, 12.8; IV, 15.0; V, 11.8 and for Cu(II) complexes: 21.1, 12.5, 14.1, and 13.5, resp., whereas 10(8) x Dt --> infinity were: 178, 769, 22.5, and 16.5, resp. and for Cu(II) complexes 83.2, 2230, 183, 51.2, resp. With 0.001, 1 or 3M HNO3 or M KNO3 addedto water phase, III had Dt --> 0 and Dt --> infinity lower by resp. one and two orders of magnitude from those evaluated with pure water.