NOx photocatalytic degradation on active concrete road surface - from experiment to real-scale application

The use of titanium dioxide (TiO2) as a photocatalyst in concrete pavements has received considerable attention in recent years due to its ability to decontaminate via photocatalytic processes. The objective of this study is to assess the effectiveness of activated concrete road in the degradation of nitrogen oxides (NOx). We have used a TiO2 and activated carbon (AC) permeable spray solution to coat concrete to assess its NOx purifying ability. A number of experiments were undertaken to ascertain the conditions that affect NOx purification. Indoor simulation experiments with active concrete road at optimum conditions show that it has good purification ability, self-regeneration and repetition ability, with a minimum decontamination rate for NO and NO2 of 37.4% and 25.84%, respectively. Outdoor experiments show that the photodegradation of NOx is related to light intensity and temperature. As the light intensity increases the reaction rate increases, and conversely as temperature increases the reaction rate decreases. (C) 2011 Elsevier Ltd. All rights reserved.