A sustainable replacement for TiO2 in photocatalyst construction materials: Hydroxyapatite-based photocatalytic additives, made from the valorisation of food wastes of marine origin
The use of waste materials and by-products in building materials is of increasing importance to improve sustainability in construction, as is the incorporation of photocatalytic materials to both combat atmospheric pollution and protect the structures and façades. This work reports the innovative use of photocatalytic hydroxyapatite (HAp) based powders, derived from Atlantic codfish bone wastes, as an additive to natural hydraulic lime mortars. HAp is the main component of bone, and hence is non-toxic and biocompatible. This is the first time that such a calcium phosphate-based photocatalyst, or indeed any fish/marine derived wastes, have been added to building materials. A key factor is th…
Templated growth of smart nanocomposite thin films: Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition of vanadyl acetylacetonate, auric acid and tetraoctyl ammonium bromide
Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition methodology has been utilised to produce nanocomposite thin films of gold nanoparticles and vanadium dioxide from vanadyl acetylacetonate and auric acid. The addition of tetraoctyl ammonium bromide (TOAB) to the precursor Solution gave control of the size and distribution of gold nanoparticles in the vanadium oxide matrix. These reactions led to vanadium dioxide films with reduced crystallite sizes and enhanced thermochromic properties. The films were analysed by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Their optical and thermochromic behaviour was also determined, This h…
Riuso e riciclo nell’industria delle costruzioni: nano-malte fotocatalitiche innovative da scarti industriali valorizzati
Questo lavoro discute della produzione di nanomalte innovative eco-composite per intonaco, progettate per combattere l’inquinamento impattante sull’involucro edilizio. I campioni sono costituiti da calce idraulica naturale funzionalizzata da vari tipi di fotocatalizzatori, prodotti a partire da scarti di industrie siderurgiche ed alimentari. Sono state condotte indagini chimico-fisiche ed, in particolare, è stata valutata l’attività fotocatalitica. Le analisi hanno dimostrato che i predetti scarti possono essere utilmente riciclati per produrre una nuova generazione di materiali da costruzione innovativi, sostenibili, economici e multifunzionali.
Vanadium dioxide and gold nanocomposite films for glazing applications
Vanadium dioxide is a material with great potential as an intelligent glazing material. The technology is based on a metal to semiconductor transition (MST) where there is an associated structural change from the higher temperature rutile structure to the lower temperature monoclinic structure. This structural transition results in significant changes in optical properties and electrical conductivity. Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition methodology has been utilised, to produce thin films of gold nano-particle vanadium dioxide nanocomposites. Good surface coverage is observed comparable to that of APCVD processes and a variety of different film thickn…
Nano-composite thermochromic thin films and their application in Energy-efficient glazing
A hybrid atmospheric pressure and aerosol-assisted chemical vapour deposition strategy is presented as a facile route for the production of vanadium dioxide nano-composite thin films. The effect of the inclusion of gold nanoparticles and the use of a surfactant molecule, tetraoctylammonium bromide, is discussed. The films were fully characterised using a wide variety of techniques, including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV/vis/NIR spectroscopy. It is shown that micro-structural changes brought about by careful control of film growth conditions, and/or the use of surfactant, lead to an enhancement of thermochromic properties. Gold nano…
Development of energy-saving innovative hydraulic mortars reusing spent coffee ground for applications in construction
This paper reports the development of green bio-composite mortars, obtained reusing spent coffee ground (SCG), an agri-food residue, in the light of the Circular Economy approach. This process can boost the sustainability in Construction and proposes an alternative to SCG disposal in landfill, potentially dangerous to humans and the environment. For the first time, specimens were produced and compared using different blends of conventional hydraulic binders (ordinary Portland cement and natural hydraulic lime); SCG partially substituted sand (up to 15 wt.%, with a 2.5% increment) for the aggregate mix. The manufacturing process was performed at ambient conditions (20°C, 65% RH) resulting hi…
Antimicrobial activity of methylene blue and toluidine blue O covalently bound to a modified silicone polymer surface
Methylene Blue or Toluidine Blue O were covalently bound to an activated silicone polymer by means of an amide condensation reaction. UV-visible absorption spectra confirmed that the dye was surface bound. The new polymers with covalently attached dye display significant bactericidal activity against Escherichia coli and Staphylococcus epidermidis with a 99.999% reduction in viable bacteria after four minutes exposure to a low power laser.
Hybrid aerosol assisted atmospheric pressure Chemical Vapour Deposition: a facile route toward nano-composite thin films?
A hybrid chemical vapour deposition strategy is presented as a facile route for the production of vanadium dioxide nano-composite thin films. The effect of the inclusion of gold nano-particles and the use of a surfactant molecule; tetraoctylammonium bromide (TOAB), is discussed. The films are fully characterised and it is shown that micro-structural changes lead to an enhancement of thermochromic properties, whilst gold nano-particles lead to a change in the films optical properties. Optical data is used in energy modelling studies to elucidate the films potential as an energy saving coating in architectural glazing.
Energy modelling studies of thermochromic glazing
Theoretically thermochromic glazing has the potential to reduce energy consumption in buildings by allowing visible light for day lighting, reducing unwanted solar gain during the cooling season, whilst allowing useful solar gain in the heating season. In this study building simulation is used to predict the savings made by novel thermochromic glazing coatings compared to standard products, for locations with different climates. The results suggest that thermochromic glazing can have a significant energy saving effect compared to current approaches.
Templated growth of smart coatings: Hybrid chemical vapour deposition of vanadyl acetylacetonate with tetraoctyl ammonium bromide
Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition methodology has been utilised to produce thin films of vanadium dioxide from vanadyl acetylacetonate. Tetraoctyl ammonium bromide (TOAB) was used in the aerosol precursor solution. The films were analysed by X-ray diffraction, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy. Their optical and thermochromic behaviour was also determined. It was found that the use of TOAB had a templating effect that led to a halving in the particle size and that this consequently led to a significant decrease in the thermochromic transition temperature of the films to 34 8C.
Optimisation of Thermochromic Thin Films on Glass; Design of Intelligent Windows
Theoretically thermochromic glazing has the potential to reduce energy consumption in buildings by allowing visible light for day lighting, reducing unwanted solar gain during the cooling season, while allowing useful solar gain in the heating season. In this study building simulation is used to predict the savings made by novel thermochromic glazing coatings compared to standard products, for locations with different climates. The results suggest that thermochromic glazing can have a significant energy saving effect compared to current approaches.