Details

Autor(en) / Beteiligte

• Ribeiro, Joana Margarida Fernandes da Silva

Titel

Photocatalytic Degradation of Micropollutants with TiO2 /Pvdf-TrFE Membranes

Ort / Verlag

ProQuest Dissertations Publishing

Erscheinungsjahr

2016

Link zum Volltext

• ProQuest

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• With the extensive use of chemicals produced through the development of technology, organic pollutants in water represent a major concern, as they constitute a potential risk for the ecosystem and human health. Furthermore, these compounds are extremely resistant to biological degradation processes and wastewater and drinking water treatment plants, causing their accumulation in water effluents. In this scope, Advanced Oxidation Processes arise as a possible solution, in particular, heterogeneous semiconductor photocatalysis. The primary aim of this study was to evaluate the effectiveness of immobilized titanium dioxide photocatalyst for the removal of pollutants from wastewater. Membranes of poly(vinylidene difluoride−trifluoroethylene) with 8% wt. P25 TiO2 nanoparticles were produced by solvent casting, with and without the inclusion of zeolites (NaY) to improve wettability, characterized and applied in the photocatalytic degradation of four micropollutants: the cationic dyes Methylene Blue, the antibiotic Ciprofloxacin, the anti-inflammatory Ibuprofen and the plastic precursor Bisphenol A. All the produced membranes possess a highly porous structure, with interconnected pores and a degree of porosity around 70%, with pore sizes ranging between 30 and 80 μm. The composites present the characteristic absorption bands of β PVDF and show unchanged polymer structure in comparison to the pristine polymeric membrane, even after four uses. The membranes with TiO2 and zeolites are more hydrophilic than the pristine membrane. The presence of TiO2 nanoparticles modify the hydrophobic nature of the membranes after subjected to ultra violet, as does the inclusion of zeolites. In the first use, the membrane with zeolites degraded Methylene blue with higher efficiency, ≃ 98% after 300 min, and a degradation rate of ≃ 0.044 min-1. The membrane without zeolites performed better in the degradation of Ciprofloxacin, ≃ 93% after 300 minutes, with a degradation rate of ≃ 0.010 min-1. Bisphenol A was not degraded and Ibuprofen seemed to generate by-products during the reaction. In the first use, after 300 minutes, Ibuprofen degraded ≃ 18 and ≃ 48% and Bisphenol A degraded ≃ 7 and ≃ 3%, using membranes with and without zeolites, respectively. Overall, reutilization of the membranes showed little to no efficiency loss after fourth degradations of Methylene blue, and a slight increase in the degradation of Ciprofloxacin, ≃ 98% with a reaction rate of ≃ 0.015 min-1, and of Ibuprofen, ≃ 66% with a reaction rate of ≃ 0.003 min-1, for membranes without zeolites after 300 minutes. The conjugation of these factors make these membranes suitable for photocatalytic degradation of micropollutants