Crystalline TiO₂ supported on stainless steel mesh deposited in a one step process via pulsed DC magnetron sputtering for wastewater treatment applications

© 2020 The Author(s). TiO2 thin films were deposited on woven stainless-steel mesh by pulsed DC magnetron sputtering, at room temperature without substrate bias or annealing. Woven stainless-steel mesh is inexpensive, flexible, semi-transparent and has a high surface area. This coating/substrate combination was selected for future photocatalytic reactor integration. The effect of operating pressure and magnetron power on coating crystallinity and photocatalytic activity were investigated. Results indicate that magnetron power is a key factor, as it affects the crystallinity and morphology of the thin films. A combination of low pressure and high-power lead to a one-step synthesis of TiO2 coatings with a mixed anatase and rutile phase. An optimised sample was produced and tested for methylene blue, methyl orange and rhodamine B decomposition under UV-A. Using various trapping agents, OH and O2- radicals were identified as the main photogenerated species responsible for the model pollutant degradation. Finally, durability tests revealed little to no photocatalytic performance deterioration after ten repeated cycles. This confirmed the suitability of this coating/substrate combination for future photocatalytic reactor integration

Colgajo de avance “house - flap” en cirugía de urgencias por desgarro perianal traumático

Paciente varón de 26 años que acude al servicio de urgencias por dolor anal de 9 horas de evolución tras caída accidental de una motocicleta. Se objetiva un desgarro cutáneo irregular en región perineal derecha de 6x6 cm con afectación de la fosa isquioanal ipsilateral y bordes desvitalizados. La lesión contacta con el margen perianal sin aparente lesión esfinteriana

Design and optimisation of a low-cost titanium dioxide-coated stainless steel mesh photocatalytic water treatment reactor

Photocatalysis has been extensively studied in recent years for environmental wastewater treatment applications. Although promising, it has yet to be globally adopted, as it faces many challenges; namely cost, complexity and efficiency. This present work focuses on the optimisation of a bespoke photocatalytic water treatment reactor. Contrary to other studies, the reactor was exclusively built from inexpensive and readily available consumer market parts, to facilitate a widespread adoption of this water treatment method. Photocatalytic TiO was synthesised and immobilised on stainless steel woven mesh in a one-step process, via reactive pulsed DC magnetron sputtering. A two-levels augmented screening design template was used to optimise the performance of the bespoke photocatalytic reactor, consisting of 20 experimental runs. Five independent variables were studied, UV light intensity, number of TiO -coated mesh layers, coating thickness, water flowrate and initial dye concentration. Methylene blue dye solution was used as a model pollutant and the removal percentage after 5 h was used as a response. A linear regression model was built from the experimental results and revealed that all first-order terms, with the exception of flowrate, were significant contributors to the model pollutant removal. Increasing the coating thickness and the number of TiO -coated mesh layers did improve the removal rate of methylene blue. These benefits cancelled each other when both variables were at their highest levels, due to a decreased light permeability through the mesh. ANOVA, lack-of-fit, and R analysis confirmed the significance of the linear regression model. Optimised conditions were identified, leading to the removal of more than 90% of the model pollutant after 5 h of UV-A illumination. The calculated pseudo-first-order constant was as high as 14.5 × 10 s , while the quantum yield was estimated to be 4.22 × 10 molecules/photons and the figure of merit was calculated at 1.14. This substrate/catalyst combination proved to be effective at degrading methylene blue, with no evident performance degradation after 10 repeated cycles, equivalent to 360 h of consecutive use. This present work demonstrates that it is possible to build an efficient photocatalytic reactor from inexpensive computer enthusiast parts, combined with a highly scalable and industry friendly photocatalyst production technique. 2 2 2 2 −5 −1 −

Photocatalytic degradation of contaminants of emerging concern using a low-cost and efficient black bismuth titanate-based water treatment reactor

Photocatalysis is recognized as a sustainable technology for wastewater treatment, but it is limited by its scalability and efficiency. Here, we report the fabrication of a bespoke photocatalytic reactor, made from readily available consumer market components. The reactor was loaded with glass rods coated with a bismuth titanate photocatalyst deposited by reactive pulsed DC magnetron sputtering. Bismuth titanate is a remarkable material, which has shown the property of increasing its photocatalytic capabilities over repeated usage due to photoinduced oxygen vacancies, forming oxygen-vacancy rich “black” bismuth titanate. The reactor was tested with different rod configurations and photocatalytic material was cycled over 25 times, equivalent to 125 h of consecutive use, against methylene blue dye under UV light. Orange II dye degradation tests carried out in the presence of scavengers revealed that photocatalytic reactions were driven by superoxide (O2∙−) and holes (h+), when using pristine bismuth titanate and by superoxide (O2∙−), electrons (e−) and holes (h+), when using “black” bismuth titanate. Finally, the reactor was used to successfully degrade levofloxacin, a typical antibiotic, which was verified by UV–Vis (ultraviolet-visible) spectroscopy and inhibition zone tests in the presence of three different pathogens (E. coli, S. aureus and A. baumannii)

Photocatalytic microfiltration membranes produced by magnetron sputtering with self-cleaning capabilities

In the present work, asymmetric alumina flat membranes were coated with TiO2 thin films of varying thickness for wastewater treatment application. The coating was produced by magnetron sputtering, a deposition technique of high industrial relevance which could enable high volume manufacturing of photocatalyst coated membranes. The photocatalyst was used against membrane fouling, by taking advantage of the self-cleaning capabilities of TiO2 when irradiated by UV light. The morphology and pore size of the coated membranes was evaluated by scanning electron microscopy. The antifouling property of the photocatalyst was assessed against two pollutants, methylene blue (MB) in aqueous phase and soybean oily emulsion. Under ultraviolet irradiation, the coating was able to restore membrane flux by degrading the fouling formed by MB, with selectivity reaching up to 86% of MB removal for the thickest TiO2 thin film. The thickness didn't appear to have a significant impact on the photocatalytic activity, but it was negatively correlated with pore size, which enables membrane pore size and selectivity to be tailored. In oily conditions, the photocatalyst was not able to prevent membrane fouling, which was attributed to fouling inside the pores, catalyst inactivation through the formation of an oil layer at its surface, and to a low radiant flux

Carbonaceous-TiO2 composite photocatalysts through reactive direct current magnetron sputtering on powdered graphene for environmental applications

An efficient photocatalytic composite material was produced by coating graphene powder with TiO2 using reactive pulsed direct-current magnetron sputtering. High-quality graphene powder with a thickness consisting of 6–10 layers was obtained by liquid-phase exfoliation of natural graphite. The process variables included the working pressure (0.7, 1.2, and 1.5 Pa), coating time (1, 2, 4, and 8 h), and graphene mass (0.1, 0.5, and 1.0 g). Raman spectroscopy, scanning electron microscopy coupled to energy dispersive spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the graphene-TiO2 nanocomposites. The results of the characterization showed efficient TiO2 deposition with anatase and rutile crystallographic structures on the powdered graphene. Additionally, it was verified that the graphene was not damaged during the coating process, thereby maintaining its unique conductive and mechanical properties. The produced material exhibited photocatalytic activity for methylene blue degradation and Escherichia coli inactivation under UV light

Obesity, the new childhood disability? An umbrella review on the association between adiposity and physical function

The adverse physical impacts of childhood obesity are increasingly being recognized. The objective of this study is to examine relationships between physical function and adiposity in youth. An umbrella review searched seven databases from inception to May 2019 for systematic reviews examining associations between adiposity and physical function in 0–20-year-olds. Findings were synthesized using the International Classification of Functioning, Disability and Health Framework and NHMRC FORM. Seventeen of 21 systematic reviews reported impairments to body function, including cardiorespiratory fitness (CRF), muscle function, balance/coordination, gait biomechanics, pain and injury. Six reviews reported activity restrictions in motor skills, running speed/agility and functional mobility, and two found inverse associations between adiposity and physical health-related quality of life (p-HRQOL). Some causal relationships indicated that adiposity inversely predicted p-HRQOL/CRF and CRF/muscle function inversely predicted adiposity. Assessments of physical function were heterogeneous and impacts on participation in life situations meaningful to the individual were largely unknown. Substantial evidence associates childhood overweight/obesity with reduced physical function. Associations were mainly cross-sectional, with causative evidence for some outcomes. Comprehensive physical function assessments by qualified health professionals are needed, along with targeted interventions to address deficits. Research should further examine causality of relationships, underlying mechanisms and participation challenges in real-life contexts.</p