Remediation of noxious pollutants using nano-titania-based photocatalytic construction materials: a review.

Nano-titania (n-TiO), due to its unique photocatalytic and hydrophobic properties, can be used to prepare self-cleaning cement-based smart building materials. The n-TiO degrades organic and inorganic pollutants through its photocatalytic action and convert them into non-toxic byproducts, i.e., improves the air quality. In this review, aspects such as methodologies of n-TiO synthesis, approaches for n-TiO loading on cementitious materials, photocatalytic properties, self-cleaning mechanism, and application of n-TiO in cement-based materials have been overviewed. Further, the n-TiO can be used either as coatings or admixtures in pavement blocks, mortars/concrete at zebra crossings, road dividers and linings, and high rise buildings. Moreover, the implications and economic aspects of n-TiO usage in cement-based materials revealed that n-TiO increases the material cost by ~ 27%, (101 to 128.1$) in comparison to conventional building materials. Furthermore, the low-cost carbonized materials such as biochars have been suggested to be used as support of n-TiO to lower the cost and improve the remediation efficiency of photocatalytic concrete.