Modification Of Membrane Materials Research Articles

Advancements in modification of membrane materials over membrane separation for biomedical applications-Review.

A comprehensive overview of various modifications carried out on polymeric membranes for biomedical applications has been presented in this review paper. In particular, different methods of carrying out these modifications have been discussed. The uniqueness of the review lies in the sense that it discusses the surface modification techniques traversing the timeline from traditionally well-established technologies to emerging new techniques, thus giving an intuitive understanding of the evolution of surface modification techniques over time. A critical comparison of the advantages and pitfalls of commonly used traditional and emerging surface modification techniques have been discussed. The paper also highlights the tuning of specific properties of polymeric membranes that are critical for their increased applications in the biomedical industry specifically in drug delivery, along with current challenges faced and where the future potential of research in the field of surface modification of membranes.

Modification of membrane materials used in dried blood spot technology by zinc oxide nanoparticles

The modification of hydrophilic fiberglass and cellulose membrane materials with zinc oxide has been investigated. The surfaces of zinc oxide nanoparticles was hydrophilized by modification with 3-amino-propyltriethoxysilane. It was shown using methods of Fourier transform IR-spectroscopy and scanning electron microscopy that coating with hydrophilized zinc oxide nanoparticles did not change the structure of glass fibers and membrane material, while the treatment of cellulose-based membrane materials caused irreversible changes in the structure of fibers and the material as a whole.

Novel Modification of PU Membranes by Cyclodextrin (CD) Crosslinking for Simultaneously Improving Selectivity and Permeability

The pervaporation is promising in the separation of phenol and water. The modification of membrane material is very important to obtain good selectivity and permeability. The novel modified polyurethane (PU) membranes crosslinked by β-cyclodextrin (CD) were prepared. The structure, crystalline properties and swelling degrees were characterized by FTIR, XRD and swelling experiments. The pervaporation performances for phenol/water were investigated. The results showed that the hydrogen bonding and crystalline structure of CD were weakened in modified membranes. The introduction of CD was advantageous for both permeability and selectivity. With CD content increased from 0 to 2.66 wt%, total flux enhanced from 8.30 kg·μm·m−2·h−1 to 14.49 kg·μm·m−2·h−1 (increased by 70%), and separation factor increased gradually from 27.81 to 49.00 (increased by 76%). With the phenol content in the feed mixture increasing, both of total flux and separation factor of PU and modified PU membranes increased. The modification to use CD as crosslinker was effective to enhance the flux and selectivity simultaneously.

Molecular Gate Membrane: Poly(amidoamine) Dendrimer/polymer Hybrid Membrane Modules for CO2 Capture

Japanese government declared a goal to reduce CO2 emissions to half of those in 2005 as the objective “Cool Earth 50”. One promising means of reducing CO2 emission is the development of integrated coal gasification combined cycle with CO2 capture & storage (IGCC-CCS). In the IGCC-CCS process, CO2 separation membranes will play an important role for reducing CO2 capture costs. Estimates indicated that the CO2 capture cost from a pressurized gas stream using a membrane would be 1,500 JPY/ton- CO2 or less.We are currently developing CO2 molecular gate membrane, with the goal of producing a new, high-performance separation membrane modules. In the concept of the molecular gate membrane, the pathway for gas molecules is occupied solely by CO2, which acts as a gate to block the passage of other gases. Consequently, the amount of H2 permeating to the permeate side of the membrane is greatly limited and high concentrations of CO2 can be obtained. Poly(amidoamine)(PAMAM) dendrimers, candidate materials for molecular gate membranes, shows high separation performance in separation of CO2/N2 and CO2/H2. In RITE, PAMAM dendrimer/polymer hybrid membranes were developed for CO2 separation from flue gas (CO2/N2) and from IGCC process (CO2/H2). Although dendrimer itself is viscous liquid, the dendrimer/polymer hybrid membranes are stable under pressure difference conditions, and thus suitable for practical use. The CO2/H2 selectivity of the membrane showed more than 30, which is required to apply membrane modules for IGCC process. From these results, a PAMAM dendrimer/polymer hybrid membrane is a promising candidate for IGCC process with CO2 capture. Based on these materials, modification of membrane materials is ongoing to improve CO2 separation performance further.In the development of commercial membrane modules using the PAMAM dendrimer/polymer hybrid materials, RITE, Kuraray Co., Ltd., Nitto Denko Corporation and Nippon Steel Engineering Co., Ltd. established Molecular Gate Membrane module Technology Research Association, and membrane materials, membrane modules and separation systems are being developed with collaboration in the research association.

Study on the integrated membrane processes of dehumidification of compressed air and vapor permeation processes

Blend modified polyimide (PI) hollow fiber membranes were used in vapor permeation for gas phase dehydration of ethanol. Dry air sweeping operation was used and the dry air was supplied by a dehumidification membrane module of compressed air. An integrated membrane process was composed. The effects of some factors, such as the modification of membrane materials, the humidity and current velocity of sweeping air, the operation temperature, on the efficiency of dehydration were discussed.

New ceramic based membranes for catalytic membrane reactorsMembranes modified by cobalt complexes with 1,3-diazoles

Modification of the surfaces of inorganic membranes which have the composition 70% Al 2 O 3 +30% ZrO 2 stabilized by Y 2 O 3 has been carried out. This was done by first reacting them with silica and then with γ-aminopropyltriethoxysilane, cyanuric chloride (or diiododecene) and 1,3-diazole (imidazole or histamine). It was found that the modification of membrane materials by disperse silica occurred only in the subsurface layer and this resulted in the microfiltration membrane acquiring ultrafiltration properties. The retentions of the silica-modified membranes with respect to dextrans of different molecular weights differed from those of the unmodified membranes. Heterogenized metal complexes of transition metals with 1,3-diazoles, grafted onto the membrane surfaces, were obtained. It was established that the cobalt metal complexes with 1,3-diazoles had a deformed tetrahedral structure and it was only the nitrogen atoms of the grafted heterocycles of imidazole which were involved in the formation of four-coordinate metal complexes. The catalytic properties of the obtained membrane materials in the model reaction of the liquid-phase oxidation of cumene have been studied and the occurrence of a radical-chain process with the participation of the catalytically active membranes has been established. The formation of radicals takes place due to the oxygenation of heterogenized metal complexes, according to the following reaction: O 2 ·Co(II)→O − 2 ·Co(III). The catalytic reaction of cumene oxidation proceeds with the participation of Co(III) catalysts according to a mechanism involving electron transfer. The synthesized catalytic membrane materials can be used for the processes of oxidation of organic compounds under mild conditions.