3D printed, plastic photocatalytic flow reactors for water purification

3D printing is known as a fast, inexpensive, reproducible method for producing prototypes but is also fast becoming recognised as a scalable, advanced manufacture process. Two types of lab-scale, 3D printed plastic, fixed-film, flow-through photocatalytic reactors are described, both of which are sinusoidal in shape, and only differ in that one has no baffles, reactor A, whereas the other has, reactor B. Both reactors are lined with a P25 TiO₂/polylactic acid (PLA) coating, which, after UVA pre-conditioning, is used to photocatalyse the bleaching of circulating aqueous solutions of either methylene blue, MB, or phenol, PhOH, repeatably, without any obvious loss of activity. The rate of the photocatalysed bleaching of MB exhibited by reactor B shows a much lower dependence upon flow rate than reactor A, due to the greater lateral mixing of the laminar flow streams produced by the baffles. The photonic efficiencies of reactor A for the photocatalysed bleaching of MB and PhOH were determined to be 0.025% and 0.052%, respectively, and the photocatalytic space-time yields (PSTY) to be 0.98 × 10^-4 and 1.49 × 10^-4 m³ of reaction solution.m^-3 reactor volume.day^-1.kW^-1, respectively. This is the first example of an all plastic, 3D printed photocatalytic reactor and demonstrates the advantages of 3D printing for prototyping. Given the 3D printing is a scalable process, possible potential areas of application are discussed briefly.