Nano-Titania Decorated Fly Ash as Self-Cleaning Antibacterial Cool Pigment

Abstract

Fly ash (FA) is an industrial waste produced in large quantities whereas nano-TiO 2 is a widely studied material for multifarious applications. Synergy of the two materials is created to produce a multifunctional composite material for low cost NIR reflective coating applications. Effective formation of a TiO 2 shell on the FA core was achieved by use of an anionic surfactant (SDS). Studies on thermal annealing of specimen of different TiO 2 loadings showed changes in morphology of TiO 2 and effects on porosity, particle size, and phase of TiO 2 . NIR reflectivity increased with increase in annealing temperatures as result of fusion of nanoparticles and formation of rutile phase. Change in porosity increased adsorption and decomposition of dye. The amorphous nature and higher surface area of nanoTiO 2 annealed at lower temperature showed better performance in zone-inhibition test to establish antimicrobial activity against Escherichia coli and Staphylococcus aureus indicating its selfcleaning nature. The present study discusses development of favorable conditions for incorporation of TiO 2 on FA while establishing the concept of making a sustainable material for energy conservation.

Highly Reflective Nanostructured Titania Shell: A Sustainable Pigment for Cool Coatings

“…Our group has been working on developing a sustainable pigment material for cool coatings. Earlier, we reported preparation of core–shell structures of nanotitania on fly ash using surfactants in an organic medium . In the present work, a greener approach has been reported for coating nanotitania on fly ash particles.…”

“…Purification of the fly ash was carried out for the removal of unburnt carbon and all forms of iron by the method reported earlier . Surface activation of fly ash was achieved by treating it with 0.08 N NaOH solution at 90 °C followed by washing until neutral.…”

Synthesis and Applications of Nano Titania Particles: A Review

“…Besides smaller particle sizes at higher concentration of surfactants in solutions produces crystalline phases of anatase or rutile because the surfactant molecules slows down the hydrolysis process therefore giving more time for crystallization [43]. The concentration of acid in the solution also affects the phase composition of the synthesized particles for example at critical con- [49]. In the process of micelle formation the sulfate anion of the SDS molecule interact with the FA core shell forming a hydrocarbon chain extending outwards [50].…”

Utilization of Coal Fly Ash and Rice Hull Ash as Geopolymer Matrix-cum-Metal Dopant Applied to Visible-Light-Active Nanotitania Photocatalyst System for Degradation of Dye in Wastewater

“…Another drawback in using TiO 2 powder in photodegradation of dyes in wastewater is its agglomeration, phase transformation and high filtration costs for recovery, which are addressed by supporting TiO 2 on a solid medium [13]. One type of material that may serve as a TiO 2 support matrix is fly ash [14][15][16] and its processed derivative, geopolymer. Geopolymers are inorganic polymers made of aluminum-silicon-oxygen cross-links, produced at temperatures lower than 100 • C by chemical activation of an aluminosilicate-rich waste material [17].…”