Interpretation of the ultrasonic effect on induction time during BaSO 4 homogeneous nucleation by a cluster coagulation model

Abstract

The effects of power ultrasound on the induction time of BaSO 4 are studied experimentally and theoretically. In the experiments, barium sulfate is precipitated by mixing aqueous BaCl 2 solution and Na 2SO 4 solution. The induction time is identified and measured by recording the change of turbidity in solution. Various energy inputs are used to investigate the effect of energy on nucleation. The results show that the induction time decreases with increasing supersaturation and increasing energy input. Employing the classical nucleation theory, the interfacial tension is estimated. In addition, the ultrasonic effects on nucleation order ( n) and the nucleation coefficient ( k N ) are also investigated. A cluster coagulation model, which brings together the current nucleation models and the theories describing the behavior of colloidal suspensions, was applied to estimate the induction time under various energy inputs. A comparison between the results of model and the results of experiments shows that the number of monomers in dominating clusters ( g ¯ ) in the solution remains constant with increasing of energy input.