Novel Materials based on Nanocrystalline Oxide Doping of Glasses

Polluted water represents a serious economic and human cost. In middle-income countries like India where water pollution is a big problem, the economic impact amounts to a loss of almost half of GDP growth in downstream regions [1]. In fact, it is estimated that every day, almost 40 million litres of wastewater enter rivers and other water bodies in India with only a tiny fraction adequately treated. Such a release of pollution upstream is associated with a significant reduction in agricultural revenues and yields.
In order to reduce contaminants, physical (filtration, adsorption), chemical and biological treatments can be used. Physical treatments based on membrane filtration are known to be more reliable than chemical and biological treatments when it comes to removing oil and other contaminants from water. Adsorption by various sorbents is considered to be the most efficient, economical and ecologically benign approach, since the pollutant can be discarded properly after adsorption, and the adsorbant can frequently be recycled or reused several times.
Aerogels, which are sponge-like materials, with up to 98% of their total volume being air (hence the name) have excellent physicochemical properties such as low density, high porosity, high surface area and adjustable surface chemistry that can be exploited in several applications. In particular, aerogels have attracted significant attention as an adsorption media for removal of several environmental and human health-threatening pollutants [2]. The use of aerogels in environmental remediation can be applied to CO2 adsorption from atmospheric air, to removal of volatile organic contaminants in industrial and municipal effluents, and to water treatment processes for adsorption of oil, hazardous organic compounds and heavy metal ions. Indeed, the above-mentioned contaminants are the major source of pollution in the contemporary world contributing to serious environmental problems such as global warming and hazards for human health.
Titania, TiO2, is an oxide material with excellent properties which are exploited in a wide range of applications, finding use as a catalyst, as a component in photoanodes in solar cells and even as a scaffold in bone implants. In particular, the excellent properties of titania as a photocatalyst, meaning that light falling on titania will enhance chemical reactions, have been applied to the degradation of pollutants under visible light [3]. Among the common crystalline forms of titania, anatase is considered as the more active phase because of its superior surface chemistry, more open framework, and better electron diffusion, which leads to an enhancement in transport efficiency and a higher band-gap. Photocatalytic activity is indeed strongly dependent on parameters such as surface area, band gap, and phase composition