Anna Trojanowska

Concentration and Fractionation of Polyphenols by Membrane Operations

BACKGROUND This review aims to present the relevant background information and current research status in concentration of polyphenols using membrane technologies. The potential implementation of membrane separation to bioactive compounds like soluble phenolics from aqueous and organic solvent solutions is gaining increasing interest in the recent years. This review does not pretend to cover the abundant published literature on the subject, but to be representative for the observed tendencies in membrane processes applications for concentration of polyphenols derived from natural products. The first part of the article includes general information regarding the polyphenols and the traditional methods for their separation (such as: thin layer chromatography; paper chromatography; gas chromatography; high performance liquid chromatography; capillary electrophoresis), while the second part presents a review of different membrane processes applied for concentration of polyphenols. Three main sources for such implementations are discussed: (1) aqueous or organic solvent extracts from plant material, (2) fruits, and (3) recovery of polyphenols from industrial waste liquids. A diversity of membrane processes are considered in a large scope of implementations ranging from lab-scale studies to pilot and semiindustrial scale operations. CONCLUSION Membrane technology is an excellent candidate to make a paradigm shift in biological active compounds fractionation/separation processes. Presented results clearly demonstrate that membrane processes are of great advantages over traditionally used methods; however, characterization of separated polyphenols has to be improved. Most of citied authors concentrated their investigation only on the total amount of polyphenols determination. Exhaustive studies including: antioxidant activities, retention index, total soluble solids, or volume reduction factor, have been only carried out by a few authors.

PVDF Membrane Morphology - Influence of Polymer Molecular Weight and Preparation Temperature

In this study, we successfully prepared nine non-woven, supported polyvinylidene fluoride (PVDF) membranes, using a phase inversion precipitation method, starting from a 15 wt % PVDF solution in N-methyl-2-pyrrolidone. Various membrane morphologies were obtained by using (1) PVDF polymers, with diverse molecular weights ranging from 300 to 700 kDa, and (2) different temperature coagulation baths (20, 40, and 60 ± 2 °C) used for the film precipitation. An environmental scanning electron microscope (ESEM) was used for surface and cross-section morphology characterization. An atomic force microscope (AFM) was employed to investigate surface roughness, while a contact angle (CA) instrument was used for membrane hydrophobicity studies. Fourier transform infrared spectroscopy (FTIR) results show that the fabricated membranes are formed by a mixture of TGTG’ chains, in α phase crystalline domains, and all-TTTT trans planar zigzag chains characteristic to β phase. Moreover, generated results indicate that the phases’ content and membrane morphologies depend on the polymer molecular weight and conditions used for the membranes’ preparation. The diversity of fabricated membranes could be applied by the End User Industries for different applications.

Applications of silver nanoparticles stabilized and/or immobilized by polymer matrixes

Abstract Nanomaterials frequently possess unique and noticeably changed physical, chemical and biological properties compared to their macro scaled corresponding item. Utilization of nanoparticles habitually requires the construction of integrated chemical systems. Most popular of these are polymer-supported nanoparticles. In this review, we provide the reader with the last developments and breakthrough technologies concerning silver nanoparticles (AgNPs), one of the most comprehensively studied nanomaterials, considering the polymer types and processes used for the nanocomposite membranes preparation.

Smart microcapsules for precise delivery systems

Photosensitive microcapsules are important targets for medical, pharmaceutical, agriculture, consumer goods and chemical companies. In this study, we report the development of UV-sensitive capsules containing vanillin as a model encapsulated active material. Polyamide microcapsule shells containing azobenzene moieties in the main chain of the polymer were fabricated by oil-in-water interfacial polymerization method. Triggered perfume release and morphological variations of the microcapsule shell during UV light irradiation were observed by means of high-performance liquid chromatography (HPLC) and optical microscopy.

Membrane contactors for CO2 capture processes – critical review

Abstract The use of membrane contactor in industrial processes is wide, and lately it started to be used in CO2 capture process mainly for gas purification or to reduce the emission. Use of the membrane contactor provides high contact surface area so the size of the absorber unit significantly decreases, which is an important factor for commercialization. The research has been caried out regarding the use of novel materials for the membrane production and absorbent solution improvements. The present review reveals the progress in membrane contactor systems for CO2 capture processes concerning solution for ceramic membrane wetting, comparison study of different polymers used for fabrication and methods of enzyme immobilization for biocomposite membrane. Also information about variety of absorbent solutions is described.

Technological solutions for encapsulation

Abstract Encapsulation offers broad scope of applications. It can be used to deliver almost everything from advanced drugs to unique consumer sensory experiences; it could be also employed as a protection system or a sensing material. This cutting-edge technology undergoes rapid growth in both academic and industrial conditions. Research in this matter is continuing to find a new application of microcapsules as well as to improve the methods of their fabrication. Therefore, in this review, we focus on the art of the encapsulation technology to provide the readers with a comprehensive and in-depth understanding of up-to-day development of microcapsule preparation methods. Our goal is to help identify the major encapsulation processes and by doing so maximize the potential value of ongoing research efforts.