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Continuous in-line separation of volatile fatty acids enables continuous fermentation
Patchara Chaichol, Master's Student, Vidyasirimedhi Institute of Science and Technology (VISTEC)
Most fermentation processes (e.g., hydrogen production) can produce volatile fatty acids (VFAs) such as acetic, butyric, propionic, and lactic acids. However, considered as by-products, VFAs can inhibit fermentation [1]. Various separation techniques of VFAs removal have been proposed including distillation [2], membrane filtration [3], liquid-liquid extraction (LLE) [4], membrane-based solvent extraction (MBSE) [5]. In this study, a continuous liquid-liquid extraction using a membrane-based in-line separation was used to separate VFAs form the fermentation liquid. Different types of solvent (xylene, ethyl acetate, toluene), solvent to feed ratio (0.5, 1, 1.5, 2) were investigate for their effects on an extraction efficiency. The continuous in-line separation opens up an opportunity for the bioprocess to be operated continuously.
Design of a continuous photocatalytic packed bed reactor for phenol degradation
Waichaya sirimongkhol, Graduate student (Master degree), Burapha University
A continuous flow packed bed reactor has been applied for photocatalytic reactions. The packings allowed for more surface area for photocatalyst immobilization. In this work, we investigated effects of operating parameters on the continuous photocatalytic degradation of phenol. The reactor was designed to handle a mesoscale flow (0.054 mL/min – 0.32 mL/min). The photocatalyst used was TiO2-P25 with 365-nm LED. The immobilization of TiO2-P25 onto borosilicate glass beads based on layer-by-layer techniques using polyethylenimine (PEI) and polystyrene sulfonate (PSS) The SEM-EDX indicated a high density of photocatalysts at 1 – 20 layers of immobilizations. Different parameters, including packing ratios, residence time, light intensities and air addition, were varied and optimized. We found that a complete degradation was achieved at a packing ratio of 2.18 and a residence time of 10 min upon the air addition. The work can potentially be used as a platform of the degradation of industrial toxic compounds.
Continuous recovery of phenolic acids from wastewaters in palm oil industry
Pattarapong Limpawattana, Master's student, Burapha University
Phenolic acids can be found in a significant amount in wastewater of the palm oil industry. These compounds are precursors for medicinal, cosmetics, and food applications[1,2] In this work, we focus on the recovery of three phenolic acids from the wastewater of the palm oil industry, namely p-coumaric acid, caffeic acid and p-hydroxybenzoic acid. Conventionally, these phenolic acids can be recovered by extraction with an organic solvent such as ethyl acetate. However, to make the process more sustainable, we explored use of hydrophobic deep eutectic solvent (DES) with the combinations of dodecanoic acid, octanoic, and decanoic acid. A number of process parameters, namely HBA:HBD ratios, pH, solvent-to-feed ratios, and temperature. The optimal extraction yields obtained were 80.26%, 82.49%, and 74.46% for caffeic acid, p-coumaric acid, and p-hydroxybenzoic acid, respectively. In order to make a process continuous, we also demonstrate its extraction in a liquid-liquid membrane-based separator.
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