Comparison of simple and economical photocatalyst immobilisation procedures

Photocatalysis is extremely useful for the removal of organic contaminants in water. However, the conditions used for preparing and fixing the catalyst to a substrate have a great effect on its performance. The determination of a suitable immobilisation procedure for specific application becomes more complicated with a plethora of methods developed over the years. The aim of this paper is to determine a suitable titanium dioxide immobilisation procedure using an economical and simple method. Various dip coating alternatives are compared: sol-gel, reverse micelles, hybrid and TiO₂ slurries. The coatings were evaluated in terms of deposition and photocatalytic activity, by weight and methylene blue demineralisation, respectively. A hybrid coating on woven fibreglass exhibited the highest amount of deposition and photocatalytic activity. Five coating cycles calcined at 500 °C for 1 h are sufficient in obtaining a favourable coating performance. SEM images showed that woven fibreglass, coated 5 times and calcined at 500 °C for 1 h, was well coated. However, some cracking and detachment was observed. The hybrid procedure outlined above will be applied in subsequent studies in our research on removal of groundwater contaminants. This work may be useful to researchers by providing the relative performance of different dip-coating alternatives tested under identical conditions.