Authors:Omar Pandoli, Tommaso Del Rosso, Ricardo Queiroz Aucélio, Alessandro Massi, Chen Xiang and Shu-Ren Hysing
A novel micromixer concept for generation of concentration gradients, inspired by a Chinese design, the traditional Chinese knot “中国结”, which features a core mesh structure allowing for a very compact design, is presented. The new concept has been designed using modern computer-aided design (CAD) and computational fluid dynamics (CFD) simulation software and validated by performing multiple experiments. The final design is found to be significantly more compact than conventional ones and allows the use of up to 15 outlet channels.
Authors:Druval S. De Sá, Bojan A. Marinkovic, Eric C. Romani, Tommaso Del Rosso, Rodrigo O. M. A. de Souza, Alessandro Massi and Omar Pandoli
We present prototyping of meso- and microfluidic photocatalytic devices, functionalized through incorporation of TiO2 nanoparticles in polydimethylsiloxane (PDMS), and comparison of their efficiencies for the degradation of rhodamine B (10−5 mol/L). The prototyping of the photocatalytic devices involves simple and low-cost procedures, which includes microchannels fabrication on PDMS, deposition and impregnation of TiO2 on PDMS, and, finally, plugging on the individual parts. For the microfluidic device with 13 μL internal volume, photocatalytic TiO2–PDMS composite was sealed by another PDMS component activated by O2 plasma (PDMS–TiO2–PDMS). For the mesofluidic device, a homemade polyetheretherketone (PEEK) flow cell with 800 μL internal volume was screwed on a steel support with a glass slide and the photocatalytic composite. The photocatalytic activities of the devices were evaluated using two different pumping flow systems: a peristaltic pump and a syringe pump, both at 0.05 mL/min under the action of 365 nm ultraviolet (UV) light. The characterization of TiO2–PDMS composite was performed by confocal Raman microscopy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The photocatalytic microreactor was the most efficient, showing high organic dye photodegradation (88.4% at 12.5 mW/cm2).