Development of a photocatalytic reactor with immobilized AC/TIO2 for turquoise blue removal

• Main Author: Gallo, Jurex Cuenca
• Format: text
• Language: English
• Published: Animo Repository 2015
• Online Access: https://animorepository.dlsu.edu.ph/etd_doctoral/393
• Institution: De La Salle University

This study is part of the Engineering Research and Development for Technology (ERDT) project of the Department of Science and Technology (DOST) entitled Photocatalytic Treatment of Colored Wastewater from Textile Industries. The study was conducted at De La Salle University (DLSU) (DLSU) from May 2008 until the 2nd quarter of 2011. The objective of this study is to develop a photocatalytic reactor with Activated Carbon/Titania (AC/TiO2) immobilized on glass plates for the color removal of Turquoise Blue Dye (TBD). AC/TiO2 was synthesized by sol-gel method and immobilized using Polyethylene Glycol (PEG) as binder. The AC/TiO2 photocatalyst was characterized for its BET surface area, pore size, pore volume, surface morphology, point of zero charge (PZC), functional groups, percentage weight of AC, elemental composition, crystallite diameter, crystal structures of TiO2 and bandgap. Optimization of the process parameters using Response Surface Methodology (RSM) based on Central Composite Design (CCD) was performed. Kinetic data were fitted in Langmuir- Hinshelwood equation. Final products in photocatalytic degradation of TBD were determined and toxicity test of effluent after photocatalytic treatment was done. Recyclability and post-characterization of the catalyst were also investigated. Finally, reactor design and pilot plant investigation were conducted. Results showed that 1:1600 AC/TiO2 (8.72% AC loading) outweighed the efficiencies exhibited by TiO2 and AC/TiO2 with higher AC loadings. Based on the % color removal, the optimum conditions in photocatalytic degradation of TBD are 15.00 mg/L initial dye concentration, initial solution pH of 3.00, 3.00 g/L catalyst loading, recirculating flow rate of 100 ml/s and UV intensity of 2.50 mW/cm2. AC/TiO2 exhibited 90.01% and 86.40% color removal of TBD and in textile wastewater with TBD respectively under UV light and only 38.50% under visible light. TBD was not totally mineralized by photocatalysis but transformed into shorter carbon chain compounds reducing its toxicity level from toxic to non-toxic. Moreover, the catalyst can be repeatedly used in 7 cycles (6 hours per cycle) without reducing its efficiency to less than 60%. In pilot scale investigation, a 54.80% color removal was observed in 1.5 hours of solar irradiation.