Flexible Bench-Scale Recirculating Flow CPC Photoreactor for Solar Photocatalytic Degradation of Methylene Blue Using Removable TiO 2

TiO2 immobilized on polyethylene (PET) nonwoven sheet was used in the solar photocatalytic degradation of methylene blue (MB). TiO2 Evonik Aeroxide P25 was used in this study. The amount of loaded TiO2 on PET was approximately 24%. Immobilization of TiO2 on PET was conducted by dip coating process followed by exposing to mild heat and pressure. TiO2/PET sheets were wrapped on removable Teflon rods inside home-made bench-scale recirculating flow Compound Parabolic Concentrator (CPC) photoreactor prototype (platform 0.7 × 0.2 × 0.4 m3). CPC photoreactor is made up of seven low iron borosilicate glass tubes connected in series. CPC reflectors are made of stainless steel 304. The prototype was mounted on a platform tilted at 30°N local latitude in Cairo. A centrifugal pump was used to circulate water containing methylene blue (MB) dye inside the glass tubes. Efficient photocatalytic degradation of MB using TiO2/PET was achieved upon the exposure to direct sunlight. Chemical oxygen demand (COD) analyses reveal the complete mineralization of MB. Durability of TiO2/PET composite was also tested under sunlight irradiation. Results indicate only 6% reduction in the amount of TiO2 after seven cycles. No significant change was observed for the physicochemical characteristics of TiO2/PET after the successive irradiation processes

Solar photocatalytic treatment of industrial wastewater utilizing recycled polymeric disposals as TiO2 supports

Heavily contaminated industrial wastewater is treated using a homemade compound parabolic reactor utilizing recycled polymeric disposals as TiO2 supports. The recycled polymeric materials include cotton, cotton lycra, polyamide, paper, polyethylene terephthalate, polypropylene, and polyurethane. The loading of TiO2 onto different support materials was investigated to identify the optimal composite. The TiO2/polyethylene terephthalate collected from Factory i (PETi) composite was selected because of its durability, strong polymer-TiO2 binding, and significant photocatalytic activity. Infrared and scanning electron microscopy characterizations confirm the strong binding and homogenous distribution of TiO2 particles over the PETi surface before and after the photocatalytic process. The solar photocatalytic treatment of the sample wastewater resulted in significant photobleaching. A significant reduction in the chemical oxygen demand (COD) and mineralization percentages of up to 42% were reported. The increased biological oxygen demand to COD ratios indicate the formation of new biodegradable species, enabling further normal biological treatment. •Profoundly contaminated industrial wastewater is treated using CPC photoreactor.•Recycled polymeric disposals were utilized as TiO2 supports.•Photocatalytic treatment of wastewater resulted in significant photobleaching.•Mineralization percentages up to 42% inside the CPC reactor were reported.•Analyses suggest formation of biodegradable species, enabling biological treatment