Showing papers in "Separation and Purification Reviews in 2016"
TL;DR: In this paper, the main effects of several important factors for partitioning, such as molecular weight of the polymer, effect of added salts, pH, electrical charges, and temperature on phase diagrams, tie-line lengths, interfacial tension and settling time of the two aqueous phases are extensively reviewed.
Abstract: Over the last years, aqueous two-phase systems (ATPS) regained an increasing interest due to their potential in the downstream processing of biomolecules. After many years with only a few articles published, a lot of effort and work has been put into studying these systems for the partitioning of a range of compounds including proteins, organic low-molecular weight molecules or metal ions. Although several research and review articles appeared, a background review on ATPS partitioning fundamentals is needed. In this article, partitioning theories and main effects of several important factors for partitioning, such as molecular weight of the polymer, effect of added salts, pH, electrical charges, and temperature on phase diagrams, tie-line lengths, interfacial tension and settling time of the two aqueous phases are extensively reviewed. The trend in ATPS research is given compiling the recent 2008–2013 research articles published in the field.
189 citations
TL;DR: The main research advances in the recovery of vanillin and syringaldehyde resulting from oxidation of lignin are addressed, covering various separation methodologies namely liquid-liquid extraction, supercritical fluid extraction, distillation, crystallization, membrane separation, and adsorption.
Abstract: Lignin is an underexploited side-stream of pulp and paper industry and biorefineries, being used for energy production at mill site or as low value material for dispersants or binding applications. However, an integrated process of reaction and separation can be implemented for the production of high added-value monomeric phenolic chemicals such as vanillin and syringaldehyde. In this review, the main research advances in the recovery of vanillin and syringaldehyde resulting from oxidation of lignin are addressed, covering various separation methodologies namely liquid-liquid extraction, supercritical fluid extraction, distillation, crystallization, membrane separation, and adsorption. Studies in this area started in the early years of the 20th century, but in the last decades several processes have been suggested, mainly for vanillin separation. Finding the ultimate industrially feasible process is still a necessary task and this review points out the most promising technologies and sequence of processes.
103 citations
TL;DR: In the early stage of membrane technology development in gas separation, utilization of polymeric membranes has gained attention due to their robustness and ease of fabrication as discussed by the authors, however, the performance is limited by the trade-off between permeability and selectivity.
Abstract: In the early stage of membrane technology development in gas separation, utilization of polymeric membranes has gained attention due to their robustness and ease of fabrication. However, the performance of polymeric membranes is limited by the trade-off between permeability and selectivity. Meanwhile, inorganic membrane is capable to exhibit great enhancement in separation performance but unfortunately its fabrication process is hard and costly. Thus, development of mixed matrix membranes (MMMs) by incorporating inorganic fillers into the polymer matrix has become a potential alternative to overcome the limitations of polymeric and inorganic membranes in gas separation. Nevertheless, fabrication of defect-free MMMs with improved separation performance and without compromising the mechanical and thermal stability is extremely difficult and challenging. In the current review paper, various types of inorganic fillers for MMMs fabrication and recent reported efforts to tailor the underlying problems on MMMs f...
97 citations
TL;DR: A review of state-of-the-art development in herbal processing and extraction methods from the year 1991 until 2015 can be found in this article, where the authors start with a brief history of herbal usage, followed by descriptions of 10 types of extraction processes and critical analysis of their relative advantages and disadvantages.
Abstract: Herbs are widely utilized in food and health industries. Their beneficial effects to the human body have been attributed to the presence of active phytochemical ingredients with some efficiency for disease treatment as well as for beauty and health enhancement. Public awareness on the adverse effects of synthetic chemical products also increased the demand for herbal products. Highly efficient herbal processing and extraction technologies have been developed to obtain the optimal amounts of active ingredients from herbs and cope with the rising demands for herbal products. This article reviews the state-of-the-art development in herbal processing and extraction methods from the year 1991 until 2015. We start with a brief history of herbal usage, followed by descriptions of 10 types of extraction processes and critical analysis of their relative advantages and disadvantages. Scale-up considerations of the extraction methods are shared, and a highlight of the current and future challenges facing the herbal ...
86 citations
TL;DR: In this paper, the effects of inorganic nano-additives on properties and performance of polymer/nanoparticle composite membranes are reviewed. And the authors demonstrate that using nanomaterials in a polymer matrix could enhance the mechanical strength and stiffness, wettability, selectivity, water permeability, and antifouling.
Abstract: Separation using selective polymeric membranes has been well-established as an energy-efficient and cost-effective technology in water treatment and many other applications involving aqueous solutions. However, limited chemical, thermal, and mechanical resistances besides their tendency to fouling and inadequate pure water flux may often restrict their applications. To this end, inorganic materials as additives have been demonstrated to be able to enhance chemical, thermal, and fouling membrane resistances, which demonstrate their great potential for developing novel membranes by using them as additives in polymer matrices. Considering the excellent characteristics of the nanosized particles, this study reviews the effects of inorganic nano-additives on properties and performance of polymer/nanoparticle composite membranes. It has been demonstrated that using nanomaterials in a polymer matrix could enhance the mechanical strength and stiffness, wettability, selectivity, water permeability, and antifouling...
78 citations
TL;DR: The principles of pressure swing adsorption (PSA) for carbon dioxide capture are reviewed in this paper, where the authors provide a better understanding of the technology so that it gains wider acceptance in the future to address the global environmental concern.
Abstract: The principles of pressure swing adsorption (PSA) for carbon dioxide capture are reviewed. Previous work on PSA, relevant modeling and experimental investigation for specifically carbon dioxide separation are also presented and significant findings highlighted. Simple rules for PSA process design based on analysis of the inherent properties of adsorbate-adsorbent systems encompassing equilibrium isotherm, adsorption kinetics, shape of breakthrough curves, screening and selection of adsorbent, bed porosity, adsorption time, purge to feed ratio, residence time, pressure equalization and rinse steps are provided to promote better understanding of the technology so that it gains wider acceptance in the future to address the global environmental concern, particularly in the removal of carbon dioxide as a greenhouse gas.
60 citations
TL;DR: Aqueous two-phase flotation (ATPF) as mentioned in this paper has been successfully applied for the separation and purification of biological materials in the field of biotechnology and has demonstrated as an effective, economical and environment-friendly technique for separation of labile biomolecules from their crude aqueous extracts of natural plants or fermentation broths, under mild separation condition.
Abstract: Aqueous two-phase flotation (ATPF), a novel technique which integrates the principles of aqueous two-phase systems and mass transfer mode of solvent sublation, has been successfully applied for the separation and purification of biological materials in the field of biotechnology. From the studies done so far, ATPF has demonstrated as an effective, economical and environment-friendly technique for separation of labile biomolecules from their crude aqueous extracts of natural plants or fermentation broths, under mild separation condition. In this article, the basic principles, experimental apparatus set up, key design variables of ATPF, ATPF applications and a comparative study between ATPF and other conventional methods are discussed. This review is intended to present a comprehensive summary on the research works carried out so far related to ATPF since its introduction in 2009 until present, which will be helpful for further research in ATPF.
50 citations
TL;DR: In this article, the authors discuss the technical aspects of the Electrodialysis with Bipolar Membranes (EDBM) as a means to treat streams rich in NaCl from reverse osmosis desalination and industrial processes in order to complete the direct delivery of chemicals for self-supply.
Abstract: Several industrial processes, such as desalination or neutralization, generate brines defined as concentrated solutions of salts in water, usually NaCl, typically discharged in the vicinities of the desalination plant or factory. To reduce the environmental impact and promote the valorization of the wasted resources, alternatives must be sought. Among sustainable alternatives for the recovery of brines, the possibility of using Electrodialysis with Bipolar Membranes (EDBM) is of interest, because it allows recovering brines as useful acids and bases. This review focuses on the discussion of the technical aspects of the EDBM as a means to treat streams rich in NaCl from reverse osmosis desalination and industrial processes in order to complete the direct delivery of chemicals for self-supply. The main environmental issues associated with desalination brine disposal are presented. The state-of-the-art of valorization of brines by EDBM to acids and bases is completed. This work concludes with an in-depth dis...
46 citations
TL;DR: A complete review on the techniques for elimination of defects including chemical vapor and liquid depositions, coke deposition, surface coatings, and hydrothermal treatments is presented in this paper.
Abstract: Characterization of zeolite membrane defects including SEM, dye permeation, bubble point and permporometry methods are presented. Experimental setup, governing equations and step by step procedure for obtaining pore sizes are discussed for the most useful method, i.e., the permporometry. A complete review on the techniques for elimination of defects including chemical vapor and liquid depositions, coke deposition, surface coatings, and hydrothermal treatments is presented. For each method, experimental setup, various modification conditions as well as performance enhancement of the membranes are comprehensively discussed. Finally, comparison between different methods is performed to find the more efficient techniques.
38 citations
TL;DR: In this article, it was shown that more than 95% of NH4-N could be recovered in the form of struvite, a magnesium-ammonium phosphate (MAP) salt, from some kinds of wastewater.
Abstract: Struvite crystallization is one of the sustainable approaches for recovering ammonium nitrogen (NH4-N) from wastewater in the form of a valuable material, in parallel with improving wastewater treatment efficiency. Focusing on NH4-N recovery, this review discusses the factors influencing struvite crystallization including the effect of foreign elements. It is shown that more than 95% of NH4-N could be recovered in the form of struvite, a magnesium-ammonium phosphate (MAP) salt, from some kinds of wastewater. This review emphasizes the role of utilizing alternative sources of Mg and P in improving the process sustainability. Additionally, it also explains how the MAP precipitation process could result with significant reduction of other pollutants contributing to total organic carbon, of color and turbidity, which support MAP integration with other treatment methods. The main options of lowering MAP recovery cost are presented; it was shown that applying low-cost materials of both Mg and P could save more ...
34 citations
TL;DR: In this article, the fundamental principles, advantages and challenges of forward osmosis (FO) membrane processes are discussed, and a review addressed the fundamental benefits and drawbacks of FO membrane processes.
Abstract: This review addressed the fundamental principles, advantages and challenges of forward osmosis (FO) membrane processes. FO is receiving more and more research attractions because it can concurrently produce clean water with low energy input and generate hydraulic energy (pressure retarded osmosis). FO typically requires zero or low hydraulic driving pressure, therefore the fouling potential of the FO membranes is much lower than conventional pressure-driven membrane processes. However, concentration polarization (CP), especially the internal CP significantly reduces the effective osmotic pressure across the FO membrane, the major driving force for the filtration process. As a result, innovative FO membrane materials like electrospun nanofibers have been explored to make low tortuosity, high porosity, and thin FO membranes with a high rejection rate of solutes and low or zero diffusion of the draw solute. The orientation of the FO membrane with active layer-facing-feed solution has less fouling than active...
TL;DR: In this paper, the authors present the inadequacies of the membrane processes by considering studies related to fouling and energy minimization, and point out the limitations hindering commercialization.
Abstract: Membrane technology is the dominant process in water treatment. However, the operation cost of membranes cannot be decreased unless the amount of fouling, the “Achilles heel” of membranes, and energy consumed are cut. The high energy requirements in commercial nanofiltration, reverse osmosis and forward osmosis technologies lead researchers to develop new membrane designs having high flux values with high salt rejection values. The purpose of this review is to present the inadequacies of the membrane processes by considering studies related to fouling and energy minimization. In this respect, lipid bilayers, block copolymers, aquaporin Z proteins and aligned carbon nanotubes can be the base to build biomimetic membranes. Such studies are summarized due to their remarkable properties in fouling control. Furthermore, the review describes the membrane design strategies and points the limitations hindering commercialization. Additionally, it is hoped that this review will trigger further needed studies.
TL;DR: In this article, the authors present a review of the use of micro-total analysis systems in food analysis and discuss the different applications of such miniaturized devices in this field, such as natural antioxidants, amino acids, proteins, dyes, vanilla flavors, DNA probes, heavy metals, toxins, allergens etc.
Abstract: One of the current trends of separation techniques in analytical chemistry is miniaturization. The aim of miniaturization is to attain better performance, shorter analysis time, and reduced reagent consumption. Capillary Electrophoresis (CE) microchips, the first generation of micro-total analysis systems, are the most used microsystems in food analysis. The scope of this review is to gather and discuss the different applications of such miniaturized devices in this field. Various analytes of food significance such as natural antioxidants, amino acids, proteins, dyes, vanilla flavors, DNA probes, heavy metals, toxins, allergens etc. have been successfully monitored using CE-microchips, either to assess food quality or to ensure food safety. Also, to deal with the high complexity of food matrices, the integration of sample preparation steps onto the chip and the use of new tools from nanotechnology for the detection step have been reported.
TL;DR: It is found that the information available in the literature is mostly based on the performance of devices in terms of the following: bacteria/viruses/particles removal, cost efficiency including maintenance and repair, capacity and flow rate of permeate and producing company.
Abstract: During emergency situations, effective and quick reactions are vital in order to supply safe and unpolluted drinking water within approved guidelines Point-of-use water treatment (PoUWT) system, for instance, portable membrane-based water treatment devices, could help affected people to survive while waiting for aids to arrive. In the context of portable membrane-based water purification devices, it is also found that most literature does not mention particle depositions and interactions, and membrane fouling mechanisms that might occur in these devices. The latter is especially important if the device is for private use for certain type of contaminant. It is found that the information available in the literature is mostly based on the performance of devices in terms of the following: bacteria/viruses/particles removal, cost efficiency including maintenance and repair, capacity and flow rate of permeate and producing company. These are discussed briefly as well.
TL;DR: A general classification of separation methods for homogeneous mixtures was attempted in this article, where phase transformations and interfacial transfers were used as two criteria: phase transformation and interphase transfer.
Abstract: A general classification of separation methods is attempted. The two criteria were phase transformations and interfacial transfers. All separation methods of homogenous mixtures were divided into five groups: (i) methods that are based on the formation of new phases by substances to be separated; (ii) methods that are based on differences in the interphase distribution processes, chromatographic methods being singled out as a separate group; (iii) membrane methods that are based on induced transfers of substances from one phase into another one across a third phase, which separates the two; (iv) separation methods within a single phase that are based on velocity and direction differences in spatial displacement of particles of substances to be separated within one fluid phase under the action of various fields; and (v) combined methods working combining previously listed methods.Descriptions of each group of separation methods include their intragroup classification and information on the most important t...
TL;DR: In this paper, the applications of nanomaterials (carbon-based inorganic and polymeric materials) in miniaturized extraction such as solid phase micro-extraction, stir-bar sorptive extraction, liquid phase micro extraction, and dispersive liquid phase extraction in the analyses of aqueous samples are described.
Abstract: Sample preparation is the backbone of any analytical procedure; it involves extraction and pre-concentration of the desired analytes; often at trace levels. The present article describes the applications of nanomaterials (carbon-based inorganic and polymeric materials) in miniaturized extraction such as solid phase micro-extraction, stir-bar sorptive extraction, liquid phase micro-extraction, and dispersive liquid phase micro-extraction in the analyses of aqueous samples. The nanoparticles used for micro-extractions are discussed on the basis of their chemical natures. The synthetic route and the preparation of nanomaterials are described along with the optimization strategies for micro-extraction. A comparison between the conventional materials and nanomaterials for micro-extraction is proposed. The key roles of the nanomaterials for the micro-extraction of different analytes such as drugs, pesticides, polycyclic aromatic hydrocarbons, proteins and peptides from aqueous samples are reported. The use of n...
TL;DR: An overview of pesticide residue analyses in nutraceuticals is given and the state of the art for sample preparation techniques applied for different types of nutr pharmaceuticals is provided.
Abstract: Nutraceutical products are plant-based materials primarily valued for their possible medicinal or therapeutic properties. According to their “natural” origin they are often perceived as being safe; however, for the prevention of economic losses, pesticides may be used against pest, mold and insects causing plant damage. Bearing in mind that a nutraceutical is a concentrated form of the plant, pesticides could be found in the final product in possibly worrying concentration. Nutraceutical products and dried herb materials typically represent very complex matrices for pesticide residue analysis, therefore a proper sample preparation protocol with appropriate clean-up steps is necessary prior to the analysis. Hence, this article gives an overview of pesticide residue analyses in nutraceuticals and provides the state of the art for sample preparation techniques applied for different types of nutraceuticals.