Antiviral activity of salt-coated materials against SARS-CoV-2.

The SARS-CoV-2 pandemic demonstrated the importance of human coronaviruses and the need to develop materials to prevent the spread of emergent respiratory viruses. Coating of surfaces with antiviral materials is a major interest in controlling spread of viruses, especially in high-risk or high-traffic areas. A number of different coatings for surfaces have been proposed, each with their own advantages and disadvantages. Here we show that simple salt coating on a range of surfaces, including a novel biomass aerogel can reduce the infectivity of SARS-CoV-2 placed onto the surface. This suggests that a simple to apply coating could be applied to a range of materials and have an antiviral effect against SARS-CoV-2, as well as other potential emerging viruses.

Experimental study of the purification performance of a MopFan-based photocatalytic air cleaning system.

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2, the virus that causes the coronavirus disease (COVID)-19, is primarily transmitted through respiratory droplets which linger in enclosed spaces, often exacerbated by HVAC systems. Although research to improve HVAC handling of SARS-CoV-2 is progressing, currently installed HVAC systems cause problems because they recirculate air and use ineffective filters against virus. This paper details the process of developing a novel method of eliminating air pollutants and suspended pathogens in enclosed spaces using Photocatalytic Oxidation (PCO) technology. It has been previously employed to remove organic contaminants and compounds from air streams using the irradiation of titanium dioxide (TiO2) surfaces with ultraviolet (UV) lights causing the disintegration of organic compounds by reactions with oxygen (O) and hydroxyl radicals (OH). The outcome was two functional prototypes that demonstrate the operation of PCO-based air purification principle. These prototypes comprise a novel TiO2 coated fibre mop system, which provide very large surface area for UV irradiation. Four commercially accessible materials were used for the construction of the mop: Tampico, Brass, Coco, and Natural synthetic. Two types of UV lights were used: 365 nm (UVA) and 270 nm (UVC). A series of tests were conducted that proved the prototype's functionality and its efficiency in lowering volatile organic compounds (VOCs) and formaldehyde (HCHO). The results shown that a MopFan with rotary mop constructed with Coco fibres and utilising UVC light achieves the best VOC and HCHO purification performance. Within 2 h, this combination lowered HCHO by 50% and VOCs by 23% approximately.

The advances of polysaccharide-based aerogels: Preparation and potential application.

Polysaccharide-based aerogels have high application value as one kind of unique functional materials. Not only has it high porosity and low-density, but also the non-toxicity and biodegradability. In recent decades, a variety of natural raw materials and their combinations along with various preparation technologies have been investigated to develop polysaccharide-based aerogels with different functions for diverse applications. This review aims to clarify a general approach in the development of polysaccharide-based aerogels regarding pore structure design, polysaccharide selection and drying methods. The relevant researches and reports of polysaccharide-based aerogels have been also classified according to the applications in environmental engineering, buildings, medical practice, packaging and electrochemistry. Furthermore, some statistical graphs have been produced to summarize those publications during the past ten years, with an aim to indicate the distribution and research trend. Finally, the approaches to improve the quality of the aerogels are discussed and some perspectives are put forward to provide a reference for the future development of polysaccharide-based aerogels.

Fabrication and characterization of a novel konjac glucomannan-based air filtration aerogels strengthened by wheat straw and okara.

The konjac glucomannan (KGM)-based aerogel as an air filtration material was fabricated through sol-gel and freeze-drying methods. Results showed that gelatin and starch addition could increase the filtration efficiency and compressive strength of aerogel significantly, due to the appearance of more microporous structure and the formation of dense structure in aerogel. The addition of wheat straw could decrease the filtration resistance and increase the breathability of KGM-based aerogel, which was attributed to the multi-cavities of wheat straw. The aerogel with wheat straw had a filtration efficiency of 93.54% for particle matters ≥ 0.3 µm, a filtration resistance 29 Pa, and an air permeability 271.42 L/s·m2. Okara addition could increase the hydrophobicity of KGM-based aerogel by increasing the water contact angle and decreasing the equilibrium water content. The water contact angle of the aerogel containing okara reached 105.4°, and the equilibrium water content was decreased by 17.03%-81.10% compared with that without okara, with relative humidity 0%-80%. The results demonstrated that the KGM-based aerogel had good performance on filtration, mechanical and hydrophobic properties, indicating high potential application as an air filtration material.

Technoeconomic modelling and environmental assessment of a modern PEMFC CHP system: a case study of an eco-house at University of Nottingham.

This simulation study is aimed to model a contemporary Proton Exchange Membrane fuel cell (PEMFC) CHP system having a 'heat and power' autonomy as well as a provision of demand-driven electrical supply to the grid. A novel nanowire-electrode PEMFC stack is adopted within this PEMFC CHP system so to effectively replace the existing natural gas fuelled durable solid oxide fuel cell (SOFC) CHP system installed at David Wilson Millennium Eco-house at University of Nottingham. The energy savings, environmental, and economic performances of the proposed PEMFC system are determined and compared to the base case (SOFC) which is operated continuously to maintain a 1.5 kWe. While to meetup the highly fluctuating and seasonal demands of heating and power like in the UK, a PEMFC is more productive and advantageous over a SOFC. The proposed PEMFC unlike to the SOFC will be able to operate and adjust its output and turn down instantly as per changing conditions of ambient temperatures and loads in terms of electricity and heat. The results of the modelling predicted that as compared to the base case scenario, this PEMFC CHP system will efficiently reduce an annual CO2 emission by 65.99% and fiscal costs by 66.74% with a viable internal rate of return as 8.93% and benefit to cost ratio as 1.02.

Effect of drying temperature on structural and thermomechanical properties of konjac glucomannan-zein blend films.

Konjac glucomannan (KGM)/zein blend films were successfully prepared by solution casting at different drying temperatures (40, 50, 60, 70 and 80°C). The effects of drying temperature on the films' structural, thermomechanical, mechanical and water barrier properties were investigated. Microstructural observations indicated that zein particles were homogeneously dispersed in KGM continuous matrix, and the blend film dried at 60°C showed the most compact and smooth surface. Dynamic mechanical thermal analysis curves showed that with increasing drying temperature from 40 to 60°C, glass transition temperature (Tg) of films increased; however, with further increase in temperature, the Tg decreased, indicating the compatibility of film components was the highest when dried at 60°C. The hydrophobicity of blend film dried at 60°C was significantly stronger than that of other blend films, supported by the highest water contact angle, and the lowest swelling ratio and solubility. Moreover, the film dried at 60°C showed the highest tensile strength, elongation at break, and the lowest water vapor permeability. Therefore 60°C was preferred for KGM/zein blend film preparation. This study indicated that intermolecular interactions among film components were greatly influenced by the drying temperature, and should be carefully noticed for film preparation.

Thermal conductivity, structure and mechanical properties of konjac glucomannan/starch based aerogel strengthened by wheat straw.

This study presents the preparation and property characterization of a konjac glucomannan (KGM)/starch based aerogel as a thermal insulation material. Wheat straw powders (a kind of agricultural waste) and starch are used to enhance aerogel physical properties such as mechanical strength and pore size distribution. Aerogel samples were made using environmentally friendly sol-gel and freeze drying methods. Results show that starch addition could strengthen the mechanical strength of aerogel significantly, and wheat straw addition could decrease aerogel pore size due to its special micron-cavity structure, with appropriate gelatin addition as the stabilizer. The aerogel formula was optimized to achieve lowest thermal conductivity and good thermal stability. Within the experimental range, aerogel with the optimized formula had a thermal conductivity 0.04641 Wm-1 K-1, a compression modulus 67.5 kPa and an elasticity 0.27. The results demonstrate the high potential of KGM/starch based aerogels enhanced with wheat straw for application in thermal insulation.