Prukraya Pongyeela, Juntima Chungsiriporn, Pornsiri Kaewpradit, and Lek Sikong

pp. 361 - 368

Abstract

Ammonia (NH₃
) is a noxious gas that can cause serious damage to human health and to the environment. Thus,
elimination of NH₃
 in waste air by treating before releasing to the atmosphere is necessary. In this study, titanium dioxide (TiO₂
)
nanoparticle Degussa P25 coating on glass cylindrical tube supporters was synthesized and used as photocatalytic in a
continuous photoreactor device. UV light source was vertically installed around the photoreactor in a stainless steel chamber.
Experiments were designed and conducted based on central composite design (CCD) and analyzed using response surface
methodology (RSM). This RSM was used to evaluate the effects of process variables and their interactions towards attainment of their optimum conditions. Three significant variables, light intensity (23-114W/m²
), waste air flow rate (1-5 l/min), and
TiO₂
 loading (1.18-5.90 g) were fitted in a quadratic model to the response of NH₃
 treatment efficiency. R²
 of 0.9783 was
satisfactorily evaluated for correlation coefficient of the quadratic model on the photocatalytic reactor. Based on statistical
analysis, the NH₃
 treatment model has been proven to be highly significant with very low probability values (<0.0001). The
optimum conditions obtained were 114 W/m² in light intensity, 1 l/min waste air flow rate, and 5.90 g TiO₂
 loading. This
resulted in 91.45% treatment of NH₃
 at 300 ppmv as obtained from the predicted model, which fitted well with the laboratory
results (90.02%). According to the study, TiO₂
 coated on glass tube supporter can effectively be used for the treatment of
NH₃
 from waste air and could possibly be applied at an industrial scale.