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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.

Zeolite has been surface modified to form novel multifunctional materials having capability for simultaneous and facile removal of heavy metals [Pb(II)], organic pollutants [methylene blue dye], and microorganisms [E. Coli, S. Aureus, and Pseudomonas] from contaminated water. The unique concept involves formation of core-shell particles with a functional core of zeolite and a porous shell of ZnO nanoflakes which not only imparts photocatalytic and antibacterial properties but also renders the surface negatively charged, thereby facilitating rapid adsorption of Pb(II) and MB. The uniform formation of ZnO nanoflakes (shell) on the zeolite (core) surface has been confirmed by XRD, DRS, FE-SEM, and TEM studies. Metal ion adsorption studies under varying conditions of time and concentration indicate that the material follows the Langmuir isotherm model and pseudo-second-order kinetics with good correlation to the experimental data. The rapid and high adsorption capacity of the material for both Pb (II) and MB has been established while factors responsible for enhanced adsorption have been discussed. The antibacterial studies against Gram negative bacteria (E. Coli and Pseudomonas) and Gram positive bacteria (S. Aureus) showed good zone inhibition characteristics. The material can be regenerated and reused besides having ease of separation using simple techniques. Being multifunctional, efficient, nontoxic, energy neutral, and recyclable with no effluent generation, the material is an efficient and sustainable alternative for water purification.

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