An engineering approach towards the design of an innovative compact photo-reactor for antibiotic removal in the frame of laboratory and pilot-plant scale

Abstract

Advanced Oxidation Processes (AOPs), in particular heterogeneous photocatalysis, have been considered as a promising method to remove antibiotics without generating hazardous intermediates. In this work, an innovative compact photoreactor was designed and tested for the degradation of the antibiotic Flumequine. The system consisted of a textile woven from both luminous and photocatalytically active fibers. The luminous fibers consisted of LED-type optical fibers and the photocatalytic fibers consist of textile fibers impregnated with TiO2. This configuration allowed for optimization of contact between the catalyst, the pollutant, and the light source. The surface morphology, elemental composition and optical properties of this photo-active fabric were characterized by SEM-EDX and by irradiance measurements. The effectiveness of the luminous textile was compared with two conventional processes: suspended TiO2, and immobilized TiO2 on cellulosic paper. The specific degradation rate obtained with the light textile was 28 times higher than that observed with slurry photocatalytic reactor and 65 times higher than in the case of TiO2 supported on cellulosic paper. Luminous textile also showed efficient performance in terms of mineralization per Watt consumed with values exceeding 77 and 419 times than those obtained with suspended TiO2 and the cellulose paper, respectively. This new configuration also improved the compactness by 3 times compared to the cellulosic paper system. The Langmuir-Hinshelwood model showed that this optical fibers-based configuration reduced the mass transfer compared to the conventional TiO2 immobilization approaches. Additionally, the extrapolation of this process to pilot scale was successfully performed. The excellent performances in terms of degradation rate, mineralization per Watt consumed, compactness, energy consumption, and reusability make luminous textiles an attractive alternative to conventional photocatalytic reactors’ design for removal of antibiotics in water and wastewater.