The effect of mixing on silver particle morphology in flow synthesis

Publication date: Available online 19 July 2018Source: Chemical Engineering ScienceAuthor(s): Tao Yang, Doris Segets, Thaseem Thajudeen, Yongsheng Han, Wolfgang PeukertAbstractSilver particles, prepared in a T-mixer under different flow rates, were selected to study the influences of mixing on particle shape evolution. Mixing effects on particle growth were visualized by scanning electron microscopy (SEM) and analysed quantitatively by sedimentation coefficient distributions derived from analytical centrifugation (AC). The mixing time under different flow rates was determined by the Villermaux-Dushman method to quantify the mixing quality. Based on the finding of a mixing-induced shape transformation from plates to dendrites, an extended growth mechanism involving mixing effects was proposed. Slow mixing leads to a non-uniform distributed reactant mixture and low effective supersaturation. This causes preferential growth of high-energy facets resulting in plate-like particles with broad, multimodal sedimentation distributions. In contrast, fast mixing, corresponding to uniform reactant mixture and thus high effective supersaturation and nucleation rate, leads to dendritic products, and narrow but bimodal sedimentation distributions. Based on these findings, a mechanism for the mixing-induced shape transition was proposed.

Source: Chemical Engineering Science - July 19, 2018 Category: Chemistry Source Type: research