Simple Fabrication of a Continuous-Flow Photocatalytic Reactor Using Dopamine-Assisted Immobilization onto a Fluoropolymer Tubing

Abstract

A flow reactor has been found to be advantageous for a photocatalytic reaction due to enhanced transport phenomena and photon transfer. A fluoropolymer is a promising material for fabricating a photocatalytic flow reactor because it is transparent, commercially available, and inexpensive. However, its high hydrophobicity and chemically inert nature makes it difficult to coat photocatalysts. In this work, we successfully developed a protocol to immobilize photocatalysts (TiO2–P25) onto the wall of a perfluoroalkoxy alkane tubing. The immobilization was enabled by the initial depositions of polydopamine and polyethyleneimine (PEI) layers. Then, through an ionic interaction, P25 was immobilized onto the PEI layer. A layer-by-layer PEI–P25 assembly yielded a high photocatalyst loading, which in turn enhanced the photocatalytic activity significantly. A continuous-flow operation of the photocatalytic methylene blue decolorization was demonstrated with negligible leaching of the photocatalysts and minimal loss in activity over time. A transport phenomenon inside the tubular reactor was modeled to elucidate the effect of the process parameters on kinetic and adsorption parameters. This simply fabricated flow reactor shows a great potential for photocatalytic applications.

Towards Heterogeneous Catalysis: A Review on Recent Advances of Depositing Nanocatalysts in Continuous–Flow Microreactors

“…The obtained catalyst layer also showed excellent performance for NB conversion. Apart from these common heterogeneous catalytic reactions, Khositanon et al [75] also immobilized a photocatalyst (TiO 2 ) onto the wall of a perfluoroalkoxy alkane tube by initially depositing a polydopamine and polyethyleneimine layer. Through alternate LBL deposition, a high photocatalyst loading was realized to enhance photocatalytic methylene blue degradation.…”

Open-source 3D printed reactors for reproducible batch and continuous-flow photon-induced chemistry: design and characterization

“…[12][13][14][15][16][17][18][19][20][21] The advancement of additive manufacturing, particularly fused deposition modeling (FDM), presents a compelling option for laboratory settings where customized solutions are often required promptly. 22,23 These processes cater to the global scientific community by enabling the design, modification, enhancement, production, and repair of smallscale systems. 14 Notably, these technologies not only ensure precise replication of designs multiple times but also expedite the dissemination of innovations, enhancements, and reproductions among fellow scientists.…”

Scale-Up of a Heterogeneous Photocatalytic Degradation Using a Photochemical Rotor–Stator Spinning Disk Reactor

“… 50 , 54 − 56 Interestingly, the photodegradation of organic dyes using TiO 2 has been extensively researched over the years and has served as a benchmark reaction for novel reactor designs, ranging from laboratory to intermediate scales and from batch to continuous-flow operation modes. 57 − 65 An additional advantage of this transformation is the possibility of easily assessing the remaining concentration of MB using conventional UV–vis spectroscopical tools. In this work, we report on the ability of the pRS-SDR to process complex aqueous gas–liquid–solid reaction streams without clogging and demonstrate that high productivity rates can be obtained for the TiO 2 -mediated aerobic photodegradation of aqueous MB.…”

“…As a suitable benchmark reaction, we selected the photocatalytic degradation of organic dyes, which are problematic to remove from wastewater effluents using conventional purification methods (Figure B). − For this application, semiconductors are often used as recoverable heterogeneous photocatalysts; a typical example being titanium dioxide (TiO 2 ) due to its chemical stability, nontoxic nature, low cost, and high photocatalytic activity. , The electron–hole pairs generated upon the excitation of TiO 2 can produce reactive radicals (so-called reactive oxygen species, Figure B), which nonselectively oxidize the organic pollutants, such as methylene blue (MB), to carbon dioxide, water, and various mineralization products. ,− Interestingly, the photodegradation of organic dyes using TiO 2 has been extensively researched over the years and has served as a benchmark reaction for novel reactor designs, ranging from laboratory to intermediate scales and from batch to continuous-flow operation modes. − An additional advantage of this transformation is the possibility of easily assessing the remaining concentration of MB using conventional UV–vis spectroscopical tools. In this work, we report on the ability of the pRS-SDR to process complex aqueous gas–liquid–solid reaction streams without clogging and demonstrate that high productivity rates can be obtained for the TiO 2 -mediated aerobic photodegradation of aqueous MB.…”