Near Infrared Sintering of a cost effective Roll to Roll water purification coating

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Near Infrared (NIR)at 250kW/m2 has been shown to sinter titanium dioxide on metal based substrates in just 12.5s. This coupled with a screen printable hybrid titania paste with nano-particulate anatase attached to a mesoporous framework enables roll to roll manufacture of a highly photoactive water purification coating. Photocatalytic breakdown of organic molecules has been exemplified by the complete photobleaching in 1/3 sun UV irradiation of 0.8M indigo carmine dye used to simulate textile dying industry effluent in developing nations. Moreover this has been achieved in 5-10 minutes using the enhanced surface area of modified nano-structured screen printed titania, as opposed to >12 hours using traditional titania pastes. The 12.5s NIR sintering step replaces a 30min 500C convective heating step and as such reduces the bottleneck on line speed of oven length vs dwell time, enabling rapid roll to roll production. Computational Fluid Dynamics and Finite Element Analysis have been used to model the heat equation within the system with Monte-Carlo ray tracing being used to calculate the radiative flux distribution and view factors within various oven configurations. Complications such as wavelength shift on dimming and conductive heat flows have been calculated or treated empirically and fed into models.

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Journal: TechConnect Briefs
Volume: 4, Advanced Manufacturing, Electronics and Microsystems: TechConnect Briefs 2015
Published: June 14, 2015
Pages: 93 - 96
Industry sector: Advanced Materials & Manufacturing
Topic: Advanced Manufacturing
ISBN: 978-1-4987-4730-1