Fluidized bed photocatalytic reactor system for disinfection and wastewater treatment

Heterogeneous photocatalysis has attracted a large number of researchers around the globe due to its intriguing advantages in the area of environmental remediation. The ability to degrade numerous pollutants and disinfect microorganisms using an inexpensive catalyst and low energy UV light (even sunlight) makes it an attractive alternative to the other available treatment technologies. However, a suitable reactor design is required for commercial application of photocatalysis. Due to lack of effective designs, the use of photocatalysis is still limited commercially. The objective of this research was to develop and optimize an effective fluidized bed type photocatalytic reactor using the specially prepared supported photocatalyst.; In this research, an integrated photocatalyst adsorbent (IPCA) mounted on the porous silica beads as the support was used as the photocatalyst. The active material in the photocatalyst was Degussa P-25 TiO2 bound to a Silicalite I zeolite adsorbent. Fluidized bed reactors with axial and multi-lamp arrangements were explored in this study. Hydrodynamics of the reactors were investigated using computational fluid dynamics (CFD) software 'Fluent'. Fluidized bed type reactors with various scales (laboratory to pilot scale) were investigated for their effectiveness in the removal of the model pollutant "Phenol" and model microorganism "E.coli". Also, the effect of adding hydrogen peroxide in the photocatalytic process to degrade phenol was investigated in this study.; Results of E.coli disinfection process suggested a higher efficiency of E.coli removal by photocatalysis compared to photolysis. From experimental results, it was found that degradation efficiency of the photocatalytic process alone in removing organic pollutants was limited. Under a certain combination of the process parameters, a particular level (∼30%) of phenol degradation can be achieved. There is an optimum level of photocatalyst loading required in the photocatalytic process to degrade phenol. The addition of hydrogen peroxide was found to be highly beneficial to degrade phenol. Results of the series of experiments suggested that a combination of a reasonably small dose of hydrogen peroxide and small amount of catalyst loading was the most efficient process. Preliminary experiments of Bisphenol-A (BPA) and sulfolane degradation on the laboratory scale proved in principle effectiveness of removal of the other model pollutants. This study indicated that there is a potential for the fluidized bed reactor with IPCA as the photocatalyst for the scale-up.