KR20110120563A - Stable supported liquid membrane for the pervaporative recovery of organics - Google Patents

Abstract

PURPOSE: A stable supported liquid membrane for collecting the pervaporation of organic materials is provided to improve the performance of the pervaporation and to improve the collecting efficiency of butanol from a multi-components-based liquid mixture. CONSTITUTION: A stable supported liquid membrane for collecting the pervaporation of organic materials includes oleyl alcohol and poly(octyl methyl) siloxane. The oleyl alcohol functions as an extracting agent. The poly(octyl methyl) siloxane functions as stabilization diluents. The organic materials are butanol. The butanol is collected from a bi-components or multi-components-based liquid mixture.

Description

Stabilized support liquid membrane for permeation recovery of organic matter {STABLE SUPPORTED LIQUID MEMBRANE FOR THE PERVAPORATIVE RECOVERY OF ORGANICS}

The present invention uses oleyl alchohol (OA) as an extractant, which is used for pervaporative recovery of organics, especially butanol, from multicomponent liquid mixture systems such as aqueous solutions and model ABE fermentation broths, It relates to a stable supported liquid membrane (SLM) comprising an octylmethyl siloxane (poly (octylmethyl) siloxane (POMS)).

Due to environmental concerns and economic problems due to crude oil depletion, many studies are currently underway to develop technologies for converting renewable resources such as butanol into alternative transport fuels. Butanol not only has low reid vapor pressure, high energy content and high blending capacity but also shows greater hydrophobicity than ethanol, making it more valuable as fuel than ethanol (Brekke, K. Butanol : an energy alternative ?, Ethanol Today , 2007, 36-39, http://www.ethanol.org/pdf/contentmgmt/March_07_ET_second ary.pdf). There is much interest in the technology for industrially producing butanol and other high value liquid fuels through acetone-butanol-ethanol (ABE) fermentation. However, the total solvent concentration of ABE fermentation is significantly lower, about 1-2% (w / v) (Jones, DT and Woods, DR Acetone-butanol fermentation revisited, Microbiological Reviews , 50, 1986, 484-524; Qureshi, N., Meagher, MM, Huang, J. and Hutkins, RW Acetone butanol ethanol (ABE) recovery by pervaporation using silicalite-silicone composite membrane from fed-batch reactor of Clostridium acetobutylicum , Journal of Membrane Science , 187, 2001, 93-102), which shows uneconomical solvent recovery in distillation.

Of the solvent recovery techniques developed to date, pervaporation is considered to be the most cost-effective alternative since it uses a highly selective membrane that is very energy efficient and separates organics from diluted solutions very easily (Shao, P. and Huang, RYM Polymeric). membrane pervaporation, Journal of Membrane Science , 287, 2007, 162-179).

Various membranes (and these, such as poly (dimethyl) siloxane (PDMS), polyvinyl alcohol (PVA) and polytetrafluoroethylene (PTFE)) in the pervaporation of diluted organic solutions Several studies have already been reported (Qureshi, N. and Blaschek, HP Butanol recovery from model solution / fermentation broth by pervaporation: evaluation of membrane performance, Biomass). and Bioenergy , 17, 1999, 175-184). Ceramic membranes (and combinations thereof) and oleyl alcohols (OA) (Matsumura, M. and Kataoka, H. Separation of dilute aqueous butanol and acetone solutions by pervaporation through liquid membranes, Biotechnology and Bioengineering , 30, 1987, 887-895), decanol (Fahim, MA, Qader, A. and Hughes, MA Extraction equilibria of acetic and propionic acids from dilute aqueous solution by several solvents, Separation Science and Technology, 27, 1992, 1809-1821) , and tri - n - octyl amine (tri- n -octylamine; TOA) ( Qin, Y., Sheth, JP and Sirkar, KK Pervaporation membrane that are highly selective for acetic acid over water, Industrial and Engineering Chemistry Research , 42, 2003, 582-595; Thongsukmak, A. and Sirkar, KK Pervaporation membranes highly selective for solvents present in fermentation broths, Journal of Membrane Several organic solvent-based supported liquid membranes (SLMs), such as Science , 302, 2007, 45-48, have also been tested. Among these membranes, SLM has been widely studied for the isolation and concentration of organic compounds by exceptionally high selectivity and mass flux (Kocherginsky, NM, Yang, Q. and Seelam, L. Recent advances in supported liquid membrane, Separation and Purification Technology , 53, 2007, 171-177). However, due to insufficient stability of the SLM it is difficult to actually use. Liquid membrane (LM) loss during pervaporation can reduce flux and selectivity, which can lead to contamination of the feed solution (Matsumura, M. and Kataoka, H. Separation of dilute aqueous butanol and acetone solutions by pervaporation through liquid membranes, Biotechnology and Bioengineering , 30, 1987, 887-895; Zha, FF, Fane, AG and Fell, CJD Instability mechanisms of supported liquid membranes in phenol transport process, Journal of Membrane Science , 107, 1995, 59-74; Thongsukmak, A. and Sirkar, KK Pervaporation membranes highly selective for solvents present in fermentation broths, Journal of Membrane Science , 302, 2007, 45-58; Kocherginsky et al., 2007).

In addition to developing relatively new SLM materials, there have been many safety improvement efforts, such as surface coating through plasma polymerization, continuous reimpregnation of LM, and barrier layer formation on the film surface (Kocherginsky et al., 2007 ). However, these approaches are very complex and impractical. A simple and possible alternative is LM mixing, which is a mixing of known extractants with stabilized diluents. However, at present, studies on the SLM mixture for the recovery of pervaporation butane for the purpose of improving the SLM stability is insufficient.

The present invention has been made as a result of intensive research in view of the above points, in particular oleyl alchohol (OA) as an extractant, poly (octylmethyl) siloxane as a stabilizing diluent It is an object to provide a stable supported liquid membrane (SLM) for pervaporative recovery of organics, in particular butanol, including POMS.

The present invention also aims to provide an SLM mixture that is effective for pervaporation recovery of butanol and other organics from diluted two-component and multicomponent liquid mixture systems.

The above object of the present invention is to select the optimum extractant and stabilized diluent through experiment and to measure the pervaporation performance of the stabilized SLM by measuring the mass flux, separation factor, pervaporation separation index (PSI) and permeation concentration and the LM Stability was achieved by evaluating LM loss.

The stabilized SLM of the present invention has excellent pervaporation performance and is excellent in recovering organic substances such as butanol.

1 is a graph showing butanol K _P values of OA and TOA at the initial butanol concentration of the aqueous phase.
2 is a graph showing the effect of OA content in butanol K _P and the hydrophobicity (contact angle) of the SLM mixture.
3 is a graph showing the effect of temperature on the separation factor at different butanol / water feed concentrations.
4 is a graph showing the effect of temperature with butanol flux at different butanol / water feed concentrations.
5 is a graph showing the effect of temperature with stability (% LM loss) and pervaporation separation index (PSI) at different butanol / water feed concentrations.

The present invention relates to a stabilized support liquid membrane (SLM) prepared by mixing a liquid membrane (LM), such as an extractant and a stabilizer diluent, wherein oleyl alchohol (OA) is used as the extractant and poly (octylmethyl) as the stabilizer diluent. The present invention relates to a stabilized support liquid membrane for pervaporation recovery of an organic material containing a mixture of poly (octylmethyl) siloxane (POMS).

The stabilized support liquid film (SLM) of the present invention can be used for pervaporation recovery of organic materials selected from organic acids such as butyric acid, acetic acid, propionic acid and palmitic acid and alcohols such as methanol, ethanol and butanol.

Example  One. Extractant  And selection of stabilized diluents and SLM  Produce

Reagents used were each purchased from different companies: oleyl alcohol (OA) (60%) and tri- n -octylamine (TOA, 98%) (Acros-Organics, USA); Poly (octylmethyl) siloxane (POMS), silanol-terminated poly (dimethyl) siloxane (PDPS) and poly (methylphenyl) siloxane (PMPS) (ABCR GmbH & Co., Karlsruhe, Germany); Silicone oils (PDMS 200 ^® ) (Aldrich, USA); 1-butanol (min. 99.0%) (Showa Chemical Co. Ltd., Japan), HPLC gradient acetone (JT Baker, USA), HPLC gradient anhydrous ethanol (Fisher Scientific), butyric acid (99 +%) (Aldrich) and methanol (Merck KGaA, Darmstadt, Germany). All reagents were used without further purification. The polypropylene flat sheet matrix used (Celgard ^® 2400) was obtained from Celgard ^® (North Carolina, USA).

The extractant was selected from OA and TOA based on the butanol partition. Mean K _P values for OA and TOA are 3.14 and 0.56, respectively (see FIG. 1). Oleyl alcohol was chosen as the extractant because oleyl alcohol exhibits a higher butanol partition coefficient ( K _P ).

Mixing of the LM was done by degassing / settling for 24 hours after vortex-mixing.

Stabilizing diluents were selected based on miscibility criteria. Poly (octylmethyl) siloxane (POMS) was chosen as the stabilizing diluent because the poly (octylmethyl) siloxane can form homologous mixtures with OA. When present at low concentrations, the OA molecules form inverted micelle clusters with hydrophobic tails arranged outward around the hydrophobic POMS to enhance mixing.

The butanol distribution of pure LM and mixed LM was carried out by shake flask method (Partition coefficient, OECD guideline). SLM was prepared by soaking a pre-weighed support matrix in LM for 12 hours. The saturated matrix was then wiped to dry and exposed to clean air for 10 minutes. The hydrophobicity of the SLM was examined by static contact angle measurement. Gas chromatography (GC) was used for ABE analysis. The stability of the SLM was evaluated by gravimetric analysis as LM loss (% w / w).

Example  2. SLM  Of mixture Butanol  Distribution and hydrophobicity

The results of butanol distribution and hydrophobicity experiments of the OA / POMS mixture prepared as in Example 1 are shown in FIG. 2. As the OA content increases, butanol K _P increases and hydrophobicity decreases due to the relatively high butanol K _P and low hydrophobicity of OA.

Example 3. SLM  Choice of mixture

The optimal SLM mixture was selected based on butanol / water pervaporation performance with 1.5% (w / v) butanol feed concentration at 35 ° C and 60 ° C. The results show that the separation performance of OA / POMS SLM increases with increasing OA content. Optimal butanol / water separation was performed at 60 ° C. with a permeate concentration of 67.25% (w / w), butanol flux of 40.96 g / m ² -h and 30% (w / w) OA / with a separation factor of 134.04. This was done using POMS SLM. All OA / POMS SLMs exhibit notable stability below 5% LM loss. From these results, 30% (w / w) OA / POMS was selected for further pervaporation studies.

Example 4. 30% (w / w) OA Of POMS SLM Using Butanol / Water permeation evaporation

Pervaporation experiments of the SLM of Example 1 were conducted at steady state conditions at a fixed operating time of 8 hours. The butanol / water pervaporation performance of 30% (w / w) OA / POMS SLM was investigated at different feed concentrations and temperatures. The high butanol separation factor (FIG. 3) with the proper butanol flux was demonstrated by SLM (FIG. 4). Optimal butanol / water pervaporation was observed at 2.5 ° C. (w / v) butanol feed concentration and 60 ° C. with a separation factor of 279.4 and 84.24 g / m ² -h and butanol flux, respectively. At elevated temperatures and higher feed concentrations (Henry's Law), the evaporation pressures of the solvent and water increase, resulting in higher partial pressure gradients, which promote solvent separation. SLM shows good stability up to 4% LM after 8 hours of experimentation (FIG. 5).

Example 5. Model ABE  Pervaporation of Fermentation Broth

Permeate butanol from model ABE culture (0.8% w / v acetone, 1.5% w / v 1-butanol, 0.5% w / v ethanol and 0.05% w / v butyric acid) at 60 ° C. using 30% OA / POMS SLM Evaporation recovery was evaluated. SLM showed good butanol separation with a separation coefficient in the order of butanol (73.58)> acetone (9.497)> ethanol (6.565)> butyric acid (Nil). However, the pervaporation performance of SLM in butanol separation from model ABE fermentation broth is considerably lower than that in butanol / water solution because the presence of other components significantly affects pervaporation separation of butanol. Nevertheless, SLM exhibits notable stability with an average LM loss of 1.95%.

Stabilized SLM of the present invention is a very useful invention in the biofuel industry because it has a feature that is very effective in the recovery of organic matter, such as butanol due to the excellent pervaporation performance.

Claims (2)

Stabilization for pervaporative recovery of organics, characterized in that it comprises oleyl alchohol (OA) as the extractant, poly (octylmethyl) siloxane (POMS) as a stabilizing diluent Supporting liquid membrane. The stabilized support liquid membrane of claim 1, wherein the organic material is butanol.

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