**3.3 The problem of oil coagulation in aqueous environment and adsorption of oil droplets over TiO2**

Because of surface tension of oil droplets on the surface of water, it hardly makes oil droplets lay flatter instead ball up. This could cancel the solar irradiation to get into micro-crevices of the oil droplets even better, which in turn can result in promptness to sluggish photoremediation process. Besides, ball up formation as the result of coagulation of oil in aqueous environment could create a kind of blanket that can entrap colloidal particles of TiO2-containing photocatalyst and cut bridge for harvesting of light meant to activate the photoremediation process. Therefore, to apply TiO2 nanocomposite in the remediation of oil spills remediation in surface waters as well as soils and make it of practical significance and attractive for largescale environmental applications, the TiO2-containing material need to be made with surface property that at same time bring about attraction of lay flattered oil droplets and adsorption to the surface of buoyant TiO2 nanocomposite, for effective solar-driven remediation of spilled oils. Such problem can be eliminated with an organic-based material that has a reduced surface energy, low density, high porosity and adsorption ability as well as good elasticity. For example, organobentonite was sufficiently enough to disturb the surface tension of oil droplets on the surface of water [18], which in other words, can make oil droplets lay flatter instead to ball up. Consequently, TiO2-containing nanocomposite that is architecturally constructed with superhydrophobicity and superoleophilicity can selectively and smartly facilitate controllable separation of oil from oil/water mixtures and subsequently photoremediate adsorbed oil over the material.

The architectural design of porosity of buoyant TiO2 nanocomposite cannot only increase the specific surface area but also provide a number of adsorption sites and paths for oils to be in retention in the material. The pore design can primarily decrease the density of the material and enable it easy to enclose oils for rapid degradation and mineralisation. For example, graphene nanosheet can be anchored into the in the architectural framework of TiO2 nanocomposite to generate micropore, meso-pore and macro-pore structures, as it was reported that it provided abundant adsorption sites for oils and organic [80–83]. For recycling and avoidance of damage, when C-C bonds are architecturally ross-linked in the framework of TiO2 nanocomposite the carbon based architecture of the material can perfectly remain in its original composition and framework. Hence, a combination of adsorption with photochemical remediation of spilled oils through the utilisation of solar energy over TiO2-based structural framework is another elegant route that can directly decompose spilled oil into inorganics without any further procedural treatment and thus, could be highly promising for practical applications in both surface waters and soils.

*Titanium Dioxide – A Missing Photo-Responsive Material for Solar-Driven Oil Spill… DOI: http://dx.doi.org/10.5772/intechopen.98631*
