Surface Fluorinated Microsized-TiO2 for Formulation of Self-Cleaning Cement

Abstract

The use of nanosized-Titanium dioxide (n-TiO2) for the formulation of self-cleaning cement has the associated drawbacks of nano-toxicity, higher cost and agglomeration in the cementitious material. These drawbacks can be avoided by the replacement of n-TiO2 with microsized-TiO2 (m-TiO2). However, m-TiO2 is less photocatalytically active as compared to n-TiO2 . Therefore, in the present work, surface fluorination of m-TiO2 has been studied to enhance its photocatlytic activity for the formulation of self-cleaning white cement. The commercially available m-TiO2 (average size 40 μm) was surface fluorinated using aqueous solutions of different molar concentrations of NaF (sodium fluoride) such as 10, 50, and 100 mmol dm-3. The surface fluorinated m-TiO2 was analyzed using diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and X-ray diffraction (XRD) analysis to observe the improvement in the physiochemical properties and photocatalytic characteristics. Further, the surface fluorinated m-TiO2 along with calcined dolomite was utilized for the formulation of self-cleaning white cement. The hence prepared self-cleaning cement was cast into cement slabs, which were then characterized by diffuse reflectance spectroscopy (DRS) and energy dispersive spectroscopy (EDS). The self-cleaning ability and photocatalytic activity of the as prepared cement slabs were evaluated through Rhodamine B (RhB) degradation test. It has been found that the use m-TiO2, which was surface fluorinated using 10 mmol dm-3 solution of NaF, remarkably enhanced the photocatalytic performance of the self-cleaning cement.