To assess the effect of photocatalysis against pollutants, degradation of nitrogen
oxide [16–18,32,36–41] was determined by continuous flow test method under
ultraviolet exposure. The same samples used before in rhodamine B test were
placed in a 3 l borosilicate reactor, in which dry air containing 0.6 ppm of NO was
passed through at a rate of 1.5 l/min. After a short period the surfaces were exposed
to UV irradiation (20 W/m2
) for at least 45 min [41]. Photocatalytic decomposition
was monitored every minute for at least 160 min by a Nitrogen Oxides Analyzer
8841 (Rancon Instruments).