3D printed, plastic photocatalytic flow reactors for water purification

Abstract

Abstract3D 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. Graphical abstract

Natural and Synthetic Polymer Fillers for Applications in 3D Printing—FDM Technology Area

“…The impact of scaffold geometry and printing infill was also discussed. Zhou et al developed a 3Dprinted compact flow reactors from PLA containing 5% of TiO 2 as a photocatalytic phase, for water purification purposes [146]. Methylene blue and phenol were used as model molecules, and the reactors were proven to be effective under single pass and circulating flow conditions, with no apparent loss of photoactivity.…”

On a seamlessly replicable circular photoreactor for lab-scale continuous flow applications

“…One way to expand the use of flow photochemistry is by using consumer-grade commercial technologies, which lower the barrier to entry for researchers: 3D printing enables the development of affordable photoreactor designs that can be iterated quickly to match specific constraints, and open-source electronic boards allow the programming of tailored control units. 24,[28][29][30][31][32][33][34][35][36][37][38] Nevertheless, it is important to note that replicating custom designs across labs may lead to inconsistencies due to slight differences in components like light sources, materials, or cooling systems. 39 This emphasizes the importance of standardizing reactor designs to guarantee reliable operation and reproducibility, requiring user-friendly, versatile, and robust designs with interchangeable parts.…”

Microfluidic platform for screening the activity of immobilized photocatalysts for degradation of organic water pollutants

“…[19][20][21][22][23][24][25] However, screening in microreactors proved to be not just fast and reproducible 26 , but also reduced the reagent and photocatalyst consumption 27 . Using solid photocatalysts in flow is challenging, and various solutions were described like immobilization as a thin film, 26,[28][29][30] loading particles as dry powders into microchannels 27 and 3D printing using a mixture of the photocatalyst with a polymeric material 31 .…”