Photocatalytic reactor, CVD technology of its preparation and water purification from pharmaceutical drugs and agricultural pesticides

Abstract

A tubular photocatalytic reactor of the immersion type for water purification from organic pollutants has been developed. Few important principles were used in the construction of the reactor, namely, a symmetrical and uniform light distribution with direct incidence of UV irradiation on the photocatalyst surface, a highly active mixing of contaminated water as a result of an air bubbling flux, that simultaneously supplying oxygen that is necessary for a photocatalytic reaction. The implemented highly active thin film photocatalyst was prepared by the Chemical Vapor Deposition (CVD) technology using titanium(isopropoxide) (TTIP) as a precursor. The factor K=Surface/Volume of this reactor is about 255m−1. Together with an effective mixing, it creates excellent contacts between the contaminants and the photocatalyst which is very favorable for water purification. The efficiency of this reactor was proven by the decomposition of some pharmaceutical drugs (Ibuprofen, Acetylsalicylic acid, Sulphanilamide, Paracetamol, Caffeine) and of some pesticides (Dimethoate, Azoxystrobin, Iprodione, Propizamid, Isoproturon, Fenarimol). The relation between the kinetic constants of photocatalysis and of photolysis is Kphotcat./Kphotolysis=2÷18. These results demonstrate the feasibility of the developed photoreactor for the degradation of recalcitrant organic pollutants, such as pharmaceuticals and pesticides in water.