Kris O’Dowd

Bio: Kris O’Dowd is an academic researcher from Institute of Technology, Sligo. The author has contributed to research in topics: Respirator & Polypropylene. The author has an hindex of 4, co-authored 5 publications receiving 116 citations.

Face masks and respirators in the fight against the COVID-19 pandemic: A review of current materials, advances and future perspectives

Abstract: The outbreak of COVID-19 has spread rapidly across the globe, greatly affecting how humans as a whole interact, work and go about their daily life. One of the key pieces of personal protective equipment (PPE) that is being utilised to return to the norm is the face mask or respirator. In this review we aim to examine face masks and respirators, looking at the current materials in use and possible future innovations that will enhance their protection against SARS-CoV-2. Previous studies concluded that cotton, natural silk and chiffon could provide above 50% efficiency. In addition, it was found that cotton quilt with a highly tangled fibrous nature provides efficient filtration in the small particle size range. Novel designs by employing various filter materials such as nanofibres, silver nanoparticles, and nano-webs on the filter surfaces to induce antimicrobial properties are also discussed in detail. Modification of N95/N99 masks to provide additional filtration of air and to deactivate the pathogens using various technologies such as low- temperature plasma is reviewed. Legislative guidelines for selecting and wearing facial protection are also discussed. The feasibility of reusing these masks will be examined as well as a discussion on the modelling of mask use and the impact wearing them can have. The use of Artificial Intelligence (AI) models and its applications to minimise or prevent the spread of the virus using face masks and respirators is also addressed. It is concluded that a significant amount of research is required for the development of highly efficient, reusable, anti-viral and thermally regulated face masks and respirators.

Photo-Fenton disinfection at near neutral pH: Process, parameter optimization and recent advances

Abstract: The photo-Fenton process is an advanced oxidation process that uses the hydroxyl radical to disinfect and decontaminate water. Its non-selectivity makes it ideal for the removal of a range of microorganisms including those with antimicrobial resistance. Optimum parameters such as pH, temperature, hydrogen peroxide and iron concentrations and the intensity and wavelength of light irradiation are important to carry out an efficient photo-Fenton process. Traditionally photo-Fenton has been carried out at low acidic pH to obtain greater efficiency, but recent studies have been performed at near neutral. The current review examines the effectiveness of the photo-Fenton process at a near neutral pH for the disinfection of water. The optimal pH was seen to be at 2.8, with the efficiency of the photo-Fenton process decreasing as the pH rises. The optimal reagent concentrations showed considerable variation depending on the iron catalyst used and the iron to hydrogen peroxide concentration used. The effect of irradiance and temperature showed improved efficiency with higher levels. Different types of microorganisms such as E. coli, Pseudomonas sp., Enterococcus faecalis, Klebsiella pneumonia, Salmonella spp., total Coliforms, MRSA, MSSA, B. subtilis, Clostridium sp., Faecal Coliform, MS2 coliphage and Curvularia sp. are also examined and the effect the process will have on them. The design of reactors, such as compound parabolic reactors are also examined. The impact of light sources, including the recent reports on LEDs, on the production of hydrogen peroxide and thereby the improvement in the overall photo-Fenton disinfection is also discussed in detail. Finally, a techno-economic analysis to explain various costs associated with photo-Fenton process has also been carried out. It is concluded that the development of new heterogeneous supported immobilised catalysts that could work at the near neutral pH is an area, which requires considerable future research.

2D MoS2: structure, mechanisms, and photocatalytic applications

Abstract: Two-dimensional (2D) molybdenum disulfide (MoS2)–based materials are of great interest because of their capacity to efficiently absorb electromagnetic spectrum in the visible region. Starting from the structural and electronic properties, this review discusses the synthesis strategies of 2D MoS2. The major photocatalytic applications of 2D MoS2 such as hydrogen evolution, pollutant degradation, self-cleaning, photoelectrochemical water splitting, and microbial disinfection are summarized. The mechanistic understanding of various photocatalytic applications of 2D MoS2 is summarized through schematic diagrams. In addition, this review outlines the methodologies for improving the 2D MoS2 photocatalysts and recapitulates the research directions in this area of semiconductor photocatalysis.

Photocatalytic degradation of antibiotic-resistant genes and bacteria using 2D nanomaterials: What is known and what are the challenges?

Abstract: As antibiotic-resistant bacteria and genes become more prevalent, novel methods to remove them from the environment need to be developed. Here, we hope to give the case for the use of two-dimensional (2D) nanomaterials that exhibit photocatalytic properties for their removal, what they can do and what the future could potentially hold for them. Why 2D materials should be used will be examined, what makes them useful and their effectiveness. The morphological effects of the crystals on photocatalytic activity will be discussed, looking at particle size effects and shape. Recent advances in the field will be highlighted, investigating novel developments in treatment and degradation. Finally, the challenges that 2D nanomaterials face for further development will be addressed, what issues they have and the hurdles they need to overcome.

Step towards the sustainable toxic dyes removal and recycling from aqueous solution- A comprehensive review

Abstract: The synthetic dyes and chemicals used in industries produce a tremendous amount of contaminated water. Most of the poisonous dyes generated from different textileindustries are released directly to the environment. As a consequence, the discharge of wastewater from a large number of textile industries without prior treatment leads to significant negative impacts on human health. The utilization of efficient and inexpensive nano-adsorbent may reduce the adverse impacts of dyes in the environment due to their unique properties. To alleviate these issues, attention has been paid to develop efficient adsorbents for the removal of undesirable species from wastewater. Efficient and selective removal of dyes is gaining importance to reduce the environmental problems. Comparison of degradation efficiencyfor different catalysts could be a holistic approach that should be taken under consideration owing to search a suitable adsorbent. An in-depth evaluation of extensive variety of advanced adsorbents reported in literature for dye degradation has been furnished. In addition to underscoring the physico-chemical properties of different adsorbents, this review also endorses the mechanisms and efficiencies within the adsorption process. The challenges of dye degradation process are focused to reduce the adverse impacts of dyes in the environment. The critical assessment of next generation adsorbents would presumably be promoted the clean and affordable water purification process in practice.

Effects of face masks on acoustic analysis and speech perception: Implications for peri-pandemic protocols.

Abstract: Wearing face masks (alongside physical distancing) provides some protection against infection from COVID-19. Face masks can also change how people communicate and subsequently affect speech signal quality. This study investigated how three common face mask types (N95, surgical, and cloth) affected acoustic analysis of speech and perceived intelligibility in healthy subjects. Acoustic measures of timing, frequency, perturbation, and power spectral density were measured. Speech intelligibility and word and sentence accuracy were also examined using the Assessment of Intelligibility of Dysarthric Speech. Mask type impacted the power distribution in frequencies above 3 kHz for the N95 mask, and above 5 kHz in surgical and cloth masks. Measures of timing and spectral tilt mainly differed with N95 mask use. Cepstral and harmonics to noise ratios remained unchanged across mask type. No differences were observed across conditions for word or sentence intelligibility measures; however, accuracy of word and sentence translations were affected by all masks. Data presented in this study show that face masks change the speech signal, but some specific acoustic features remain largely unaffected (e.g., measures of voice quality) irrespective of mask type. Outcomes have bearing on how future speech studies are run when personal protective equipment is worn.