Surface contamination by microbes is a major public health concern. A damp environment is one of potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO₂) can effectively curb this growing threat. Metal-doped titania in anatase phase has been proven as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu)-doped TiO₂ (Cu-TiO₂) was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO₂ was carried out via sol-gel technique. Cu-TiO₂ further calcined at various temperatures (in the range of 500–700 °C) to evaluate the thermal stability of TiO₂ anatase phase. The physico-chemical properties of the samples were characterized through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV–visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO₂ was maintained well, up to 650 °C, by the Cu dopant. UV–vis results suggested that the visible light absorption property of Cu-TiO₂ was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasize the introduction of Cu⁺ and Cu²⁺ ions by replacing Ti⁴⁺ ions in the TiO₂ lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9999%) was attained in 30 min of visible light irradiation by Cu-TiO₂.

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.

Marine algae have emerged as an alternative feedstock for the production of a number of renewable fuels, including biogas. In addition to energy potential, other characteristics make them attractive as an energy source, including their ability to absorb carbon dioxide (CO₂), higher productivity rates than land-based crops and the lack of water use or land competition. For Ireland, biofuels from marine algae can play an important role by reducing imports of fossil fuels as well as providing the necessary energy in rural communities. In this study, five potential seaweed species common in Irish waters, Saccorhiza polyschides, Ulva sp., Laminaria digitata, Fucus serratus and Saccharina latissima, were co-digested individually with bovine slurry. Batch reactors of 120 ml and 1000 ml were set up and incubated at 35°C to investigate their suitability for production of biogas. Digesters fed with S. latissima produced the maximum methane yield (335 ml g volatile solids⁻¹ (g_VS⁻¹)) followed by S. polyschides with 255 ml g_VS⁻¹. L. digitata produced 246 ml g_VS⁻¹ and the lowest yields were from the green seaweed Ulva sp. 191 ml g_VS⁻¹. The methane and CO₂ percentages ranged between 50–72% and 10–45%, respectively. The results demonstrated that the seaweed species investigated are good feedstocks candidates for the production of biogas and methane as a source of energy. Their use on a large-scale process will require further investigation to increase yields and reduce production costs.

Increased legislative constraints have fuelled an interest in developing sustainable and economical methods for sludge digestion. Autothermal thermophilic aerobic digestion (ATAD) is a robust process that produces Class A biosolids from a wide range of organic sludge (e.g., animal waste, sewage sludge, food processing waste etc.). The advantages of this technology include good biomass biodegradation, pasteurization and process stability. Thermophilic temperatures result from the metabolic heat released by microorganisms during digestion. Efficient aeration and mixing are needed in addition to adequate reactor insulation to maintain thermophilic temperatures. Significant advances have been made in the optimization and adaptation of ATAD technology since it was first introduced in the early 1970s. Continuing innovation and advancement of the process is reflected in the number of patents for “next” generation technologies. Despite the apparent benefits of this process, ATAD is still not well understood. This article seeks to establish the existing state-of-the-art for the ATAD process. Information from a wide range of sources is presented to provide an insight into the key issues, discuss some of the advantages and perceived disadvantages, and list some of its operating limitations.

Seaweeds are a valuable feedstock in the production of biofuels such as biogas. In order to achieve higher conversion rates, the biomass requires a pretreatment step. However, the use of harsh conditions is detrimental to the environment and negatively affects the biochemical composition of the seaweed, lowering the yields of the products. In this study, Laminaria digitata and Saccharina latissima were pretreated with organic acids and enzymes. The extent of hydrolysis was evaluated by the concentration of reducing sugars (RS) released from the seaweed. Thereafter, the effect of pretreatments on biogas production from L. digitata was investigated in 120 ml batch reactors incubated at 35°C. Oxalic acid and the enzymatic preparation Cellulase (Sigma C9748) improved the recovery of RS. Pretreatments inhibited the anaerobic digestion process and only a 6% increase in biogas production was obtained when the biomass was subjected to a combination of 2.5% citric acid and Cellulase.