Date

2021-9

Author

Çağlar, Toprak

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Butanol is a versatile chemical used in many different fields such as electronics, cosmetics, and textiles, and the synthesis of many other chemicals. In fermentative butanol production, in addition to butanol; acetone and ethanol are released in the aqueous environment, too. To separate butanol from this mixture, which is called the ABE mixture, different methods are available. The project's main purpose is to develop an alternative method to these separation techniques by using Micellar Enhanced Ultrafiltration (MEUF) method. In the MEUF method, above certain surfactant concentration and solution temperature values, aggregates are formed. These aggregates, called micelles, trap small organic substances within. Then, using ultrafiltration membranes with a pore size much larger than the materials to be separated, organic materials trapped inside the micelles are separated from the rest of the solution. In this study, non-ionic surfactants called Pluronics were used. Firstly, based on the permeate flow rate and the surfactant's rejection values; membrane selections were carried out (1 kDa ultrafiltration membrane and NF90 as nanofiltration membrane) and the optimum operating pressure of the selected membrane was determined as 3 bar. Then, rejection performance of butanol was determined by using Pluronic F127, P123, L101, and L61 nonionic surfactants and their mixtures of different concentrations. When 1kDa membrane is used, the solution of 6.21wt.% P123 + 0.5wt.% L101 exhibited the best butanol separation performance. When NF90 membrane is used, solutions containing in addition to 1wt.% L101; 3 and 1wt.% P123 had exhibited the best butanol separation performances. When the separation of butanol from ABE mixture was tested with 1wt.% P123 + 1wt.% L101 among the best butanol separation performing surfactant couples, approximately 1.35% acetone, 68.19% butanol, and 26.87% ethanol rejection were obtained. Also, when the separation was tested with 6.21wt.% P123 + 0.5.% L101, rejections were approximately 23.44% for acetone, 66.09% for butanol, and 19.97% for ethanol. When process calculations were conducted for a three-stage filtration, based on result of the ABE experiments with 1 kDa membrane and Pluronic P123 wt.%: L101 wt.% = 6.21:0.5, at the end of the third stage; acetone, butanol, and ethanol concentrations are expected to be 5.9, 74.2, 6.1 g/L, respectively. On the other hand, for the NF90 membrane and Pluronic P123 wt.%: L101 wt.% = 1:1, concentrations of 5.3, 99, 7.9 g/L would be expected, respectively.

Subject Keywords

Micellar enhanced ultrafiltration, Butanol, Pluronic, Surfactant, ABE fermentation

URI

https://hdl.handle.net/11511/92884

Collections

Graduate School of Natural and Applied Sciences, Thesis