Solar and artificial UV inactivation of bacterial microbes by Ca-alginate immobilized TiO2 assisted by H2O2 using fluidized bed photoreactors


In this work, TiO2 (Degussa, P-25) supported on calcium alginate pearls was evaluated as catalyst for the photocatalytic inhibition of pathogenic microorganisms. Considering that water samples were taken directly from a natural source, a primary treatment (coagulation, sedimentation and filtration) was executed to remove solids and impurities. Photocatalytic experiments were carried out in two types of laboratory scale equipments, one using an annular UV irradiated reactor and the other a solar UV parabolic collector, both operated in the fluidized bed mode. H2O2 was included to the reactive mixture in order to enhance the photodegradation rate. The Response Surface Methodology and the Box-Behnken experimental design techniques were applied as tools for the optimization of the operational conditions of the UV water purification system. Thus, the influence of UV radiation, TiO2 dose and H2O2 concentration on the faecal and total coliform percentage degradation were statistically analysed. The following optimal operational conditions were found: UV radiation = 310 nm, TiO2 dose = 0.2 g/L and H2O2 concentration = 30 mg/L. After water treatment at optimized conditions, total microorganism growing inhibition was observed. Additional experiments allowed proving the reusability of the immobilized catalyst. © 2014 Science & Technology Network, Inc.


Palabras clave

Alginate, Bacteria, Catalysts, Chemical reactors, Chemical water treatment, Fluid catalytic cracking, Photocatalysis, Removal, Reusability, Titanium dioxide, Ultraviolet radiation, Water filtration, Bacterial inactivation, Box-Behnken experimental design, Calcium alginate, Fluidized bed photoreactors, Fluidized bed reactors, Pathogenic microorganisms, Response surface methodology, Water purification systems, Fluidized beds