Reducing Taylor-Aris dispersion by exploiting lateral convection associated with acoustic streaming

•Acoustic streaming reduces axial dispersion in Poiseuille flows.•Lateral mass transfer reduces the vessel dispersion number by half.•Acoustic streaming halves the C-term of the plate height equation.•The flow velocity can be doubled with similar chromatographic performance. Flow physicochemical processes, like adsorption/desorption-based separations and chemical conversions in open rectangular microfluidic channels are fundamentally limited by axial dispersion. In this contribution, the implementation of acoustics is investigated to reduce axial dispersion in microchannels. The extent of dispersion reduction is studied by means of plug injections. It was observed that the long range vortex flow of acoustic streaming can efficiently reduce dispersion by more than a factor of two. The observations made in the present study pave the way towards the development of novel, highly efficient analytical or preparative separations and microreactors with uniform residence time distributions. We elaborate on the practical implementations of both areas.