Enhanced photocatalytic efficiency and long-term performance of TiO2 in cementitious materials by activated zeolite fly ash bead carrier

This study investigated the strategy of using zeolite fly ash bead (ZFAB) as a carrier of TiO2 photocatalyst to improve the photocatalytic efficiency and long-term performance of photocatalytic cementitious materials. Various photocatalytic cementitious specimens with different ZFAB/TiO2 dosages were prepared by surface sprayed and intermixed methods. Their characteristics and photocatalytic effects were evaluated. It was found that ZFAB could improve the exposure degree of TiO2 particles in cement matrix surface, and the exposure contents were dependent on ZFAB/TiO2 incorporation methods and dosages. The photocatalytic results showed that all ZFAB/TiO2 applied cementitious samples performed better photocatalytic effects and long-term performance than that of samples prepared with pure TiO2. Moreover, the photocatalytic effects increased with the increase of ZFAB/TiO2 dosages, and ZFAB/TiO2 surface-sprayed samples displayed better effects than that of ZFAB/TiO2 inter-mixed samples. These results indicates that ZFAB is useful to enhance the photocatalytic efficiency of TiO2 in cementitious materials, which could reduce the cover risks of cement hydrates on TiO2 particles, and improve its dispersibility and exposure degree as well. Thus, the use of ZFAB could provide a potential method for high efficiency and long-term application of TiO2 in construction field. (C) 2016 Elsevier Ltd. All rights reserved.