Membrane-assisted solvent extraction

A modified extraction cell containing a bag-shaped membrane made of LDPE, instead of an FS membrane, was designed to contain the extraction solvent for the extraction of polycyclic musk compounds and pharmaceuticals in wastewater.60 The extraction cell was further developed in terms of membrane design and material. A dense nonporous PP membrane was preferably chosen as a membrane bag in the extraction cell, which was incorporated into a fully automated MASI device that is now commercially available from Gerstel (MUlheim an der Ruhr, Germany). 

This device has been applied for the extraction of different classes of organic species in wastewater.61 

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Hauser, B., P. Popp, and E. Kleine-Benne (2002). Membrane-assisted solvent extraction of triazines and other semi-volatile contaminants directly coupled to large-volume injection-gas chromatography-mass spectrometric detection. J. Chromatogr. A, 963 27-36. 

Hauser B. and P. Popp. 2001. Membrane-assisted solvent extraction of organochlorine compounds in combination with large-volume injection/gas chromatography-electron capture detection. J. Sep. Sci. 24 551-560. 

Ortiz, I. and Irabien, A. (2009) Membrane-assisted solvent extraction for the recovery of metallic pollutants process modeling and optimization, in Handbook of Membrane Separations (eds A.K. Pabby, S.S.H. Rizviand A.M. Sastre), CRC Press, p. 1023. 

Membrane Techniques The interest in membrane techniques for sample preparation arose in the 1980s. Extraction selectivity makes membrane techniques an alternative to the typical sample enrichment methods of the 1990s. Different membrane systems were designed and introduced into analytical practice some more prominent examples are polymeric membrane extraction (PME), microporous membrane liquid-liquid extraction (MMLLE), and supported liquid membrane extraction (SEME) [106, 107]. Membrane-assisted solvent extraction (MASE) coupled with GC-MS is another example of a system that allows analysis of organic pollutants in environmental samples [108-111] ... 

Vincelet, C., Rousse, J.M., Benanou, D. Experimental designs dedicated to the evaluation of a membrane extraction method membrane-assisted solvent extraction for compoimds having different polarities by means of gas chromatography-mass detection. Anal. Bioanal. Chem. 396, 2285-2292(2010)... 

Iparraguirre, A., Navarro, P., Prieto, A., Rodil, R., Olivares, M., Fernandez, L.A., Zuloaga, O. Membrane-assisted solvent extraction coupled to large volume injection-gas chromatography-mass spectrometry for the determination of a variety of endocrine disrupting compounds in environmental water samples. Anal. Bioanal. Chem. 402, 2897-2907 (2012)... 

Melcher [41 3] first described both these principles in cylindrical configurations, utilizing thin silicone tubes in flow systems. More recently, Hauser et al [44] introduced the principle of MASE (membrane-assisted solvent extraction), which comprises a polypropylene bag in an autosampler vial with an organic solvent inside the bag. This device is commercialized by Gerstel (Mulheim an der Ruhr, Germany). 

Membrane technology may become essential if zero-discharge mills become a requirement or legislation on water use becomes very restrictive. The type of membrane fractionation required varies according to the use that is to be made of the treated water. This issue is addressed in Chapter 35, which describes the apphcation of membrane processes in the pulp and paper industry for treatment of the effluent generated. Chapter 36 focuses on the apphcation of membrane bioreactors in wastewater treatment. Chapter 37 describes the apphcations of hollow fiber contactors in membrane-assisted solvent extraction for the recovery of metallic pollutants. The apphcations of membrane contactors in the treatment of gaseous waste streams are presented in Chapter 38. Chapter 39 deals with an important development in the strip dispersion technique for actinide recovery/metal separation. Chapter 40 focuses on electrically enhanced membrane separation and catalysis. Chapter 41 contains important case studies on the treatment of effluent in the leather industry. The case studies cover the work carried out at pilot plant level with membrane bioreactors and reverse osmosis. Development in nanofiltration and a case study on the recovery of impurity-free sodium thiocyanate in the acrylic industry are described in Chapter 42. 

Membrane-Assisted Solvent Extraction for the Recovery of Metallic Pollutants Process Modeling and Optimization... 

Membrane-assisted solvent extraction processes have known an increasing number of applications in the last decades [1 ]. This technique not only overcomes the limitations of conventional liquid extraction, such as flooding, intimate mixing, limitations on phase flow rate variations, and requirement of density difference but also provides a large surface area of mass transfer per volume of contactor [5]. Excellent reviews of the technology and its applications were presented by Ho and Sirkar in 1992 [6], and by Gabelman and Hwang [7]. 

The design of any process has to be supported by a proper understanding of the system behavior. Next, the kinetics of the simultaneous extraction and back-extraction processes of two metallic ions by membrane-assisted solvent extraction is analyzed theoretically. 

Decontamination of Groundwater by Using Membrane-Assisted Solvent Extraction... 

The extraction techniques described in this book fulfill many of Anastas and Warner s principles. For example, the use of supercritical carbon dioxide (SC-CO2) as the sole extraction solvent results in a nonpolluting process (prevention of waste and safer solvents and auxiliaries). Other beneficial properties of supercritical CO2 include fast diffusivity and nearly zero surface tension, which lead to extremely efficient extractions. In Chapters 2-4, applications of SC-CO2 as an extraction solvent are described. Ethanol and water are also environmentally friendly solvents that can be used as extraction media in many applications (see Chapters 5-7). Pressurized hot water ( 100-200 °C) in particular is a safe and nonpolluting solvent that has a similar dielectric constant to polar organic solvents, such as ethanol or acetone. Hence, pressurized hot water is a viable green alternative to many current extraction processes that use toxic organic solvents. Similarly, pressurized hot ethanol is an excellent solvent for the extraction of most medium polar to nonpolar organic molecules. Some of the techniques, such as membrane-assisted solvent extraction, described in Chapter 10, use organic solvents but in much smaller amounts compared to classical extraction techniques. Other techniques, for instance solid-phase microextraction and stir-bar sorptive extraction, described in Chapter 11, use no solvents. 

In this introductory book chapter, several modem extraction techniques will be described, including supercritical fluid extraction, pressurized liquid extraction, pressurized hot Avater extraction, microwave assisted extraction, membrane-assisted solvent extraction, solid phase micro extraction and stir-bar sorptive extraction. These are techniques that meet many of today s requirements in terms of environmental sustainability, speed and automation. Basic principles of operation as well as method optimization will be discussed and compared for the different techniques. Both analytical and industrial applications will be discussed, together with commercial instruments available on the market. Key references will be given, and conclusions regarding applicability of the different techniques with respect to sample e, target-molecules and analytical vs. large-scale applications. 

Schellin et al., (25) reported a membrane-assisted solvent extraction combined with large volume injection GC-MS for determination of organophosphorus pesticides in wine samples. The method involved filling a... 

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