The use of photocatalytic cementitious coatings to reduce nitric oxide from ambient air

Titanuim dioxide represents a novel photocatalyst material that can be used in different ways for air pollutants remediation. Air pollutants that are spreaded in the surrounding air could be transferred to more complex materials, especially in the presence of sunlight. To study the possibility for the reduction of these pollutants a laboratory tests have been conducted on the coated specimen substrate by using nitric oxide as pollutant gas, and there efficiency in gas removal was monitored with time. Two different particle sizes of TiO2 have been used; micro with particle size range between 150-200 nm and nano PC105 with particle size 20+ 5 nm, both are 100% anatse. Two coatings methods were applied on cementitious substrate material dip and spray to study the photochemical reaction with TiO2, aqueous solution prepared by dispersing 3g/L of TiO2 with deionized water and ethanol. Results show that using nano and micro size TiO2 aqueous solutions were effective in the removal of nitric oxide with variations in the time consumed for the removal. Using nano aqueous solution in both dip and spray methods gives the same removal efficiency reached to 98.85% ,while using micro aqueous solution the removal reached to 98.08% when dip method was used and 87.69% when spray method was used.