Development of photoelectrocatalytic membranes based on TiO2 and Al2O3 modified and applied in the treatment of organic contaminants and microorganisms in aqueous solution

Abstract

Effective technologies for the treatment of water and effluents represent a challenge of our society. For this purpose, the combination of conventional techniques of treatments with advanced oxidative processes such as photoelectrocatalysis (PEC) can be considered as a promising alternative. The present project proposes to synthesize, characterize and apply membranes of separation with photoelectrocatalytic characteristics in order to develop innovative separation systems simultaneously with the degradation/disinfection of organic pollutants and microorganisms in water. Three membrane models will be tested: i) Al2O3 membranes modified with carbon nanotubes (MWNC) and WO3 as semiconductor, synthesized by extrusion; ii) Al2O3 nanotubular membranes coated by CuO; iii) TiO2 nanotubular membranes autodoped with Ti+3 via electrochemical reduction. The evaluation of structure, stability and photoactivity will be performed using scanning electron microscopy (SEM) coupled with X-ray dispersive energy analysis (EDS), X-ray diffraction (XRD), diffuse reflectance spectroscopy and electrochemical measurements. The applicability of the membranes will be evaluated for three different pollutant models: (a) the dye reactive red 120 and (b) the tannic acid as representatives of organic contaminants and (c) the fungus Candida parapsilosis as a model for microorganisms. In the final step, we hope to apply the best membranes in real samples from hemodialysis centers inoculated with microorganism. The efficiency of degradation and inactivation of the pollutants will be evaluated through high performance liquid chromatography, total organic carbon removal, UV-Vis spectroscopy and microbial counting measurements. In summary, it is expected that the synergy between the two techniques can eliminates the main limitation of filtration systems that is the pore fouling and also allows the physical removal of the contaminants as well as the oxidation of the organic compounds and inactivation of the microorganisms.