Investigation of hybrid ion-exchange membranes reinforced with non-woven metal meshes for electro-dialysis applications

Salt and solvent permeations across ion-exchange membranes used in electro-dialysis are directly related to the membrane material structure and chemistry. Although primarily used for aqueous effluents desalination, electro-dialysis was recently shown to be a promising technology for industrial wastewater and co-solvent mixtures purification. The harsh working conditions imposed by these liquid effluents, including high suspended solids, require the development of more chemically and mechanically resistant membranes. In this study, commercial porous stainless steel media filters (240 μm thick) were used as a backbone to prepare hybrid ion-exchange membranes by casting ion-exchange materials within the porous metal structure. The surface of the metal reinforcements was modified by plasma treatment prior to sol-gel silane grafting to improve the interface between the metal and the ion-exchange resins. The morphology of novel hybrid materials and the interface between the metal fibers and the ion-exchange material have been characterized using techniques such as scanning electron microscopy and FTIR mapping. The thickness of the silane coating was found to lie between 1 and 2 μm while water contact angle tests performed on membrane surfaces and corrosion test behaviors revealed the formation of a thin passivating oxide layer on the material surfaces providing anchoring for the silane grafting and adequate surface energy for the proper incorporation of the ion-exchange material. The hybrid membranes desalination performance were then tested in a bench top electro-dialysis cell over a range of flow rate, current densities and salt concentration conditions to evaluate the ability of the novel hybrid materials to desalinate model streams. The performance of the hybrid membranes were benchmarked and critically compared against commercially available membranes (Selemion™). Although the salt transfer kinetics across the hybrid ion-exchange composite membranes were shown to be comparable to that of the commercial membranes, the low porosity of the stainless steel reinforcements, around 60%, was shown to impede absolute salt permeations. The hybrid ion-exchange membranes were however found to be competitive at low current density and low flow velocity desalination conditions.

Investigation of hybrid ion-exchange membranes reinforced with non-woven metal meshes for electro-dialysis applications

Salt and solvent permeations across ion-exchange membranes used in electro-dialysis are directly related to the membrane material structure and chemistry. Although primarily used for aqueous effluents desalination, electro-dialysis was recently shown to be a promising technology for industrial wastewater and co-solvent mixtures purification. The harsh working conditions imposed by these liquid effluents, including high suspended solids, require the development of more chemically and mechanically resistant membranes. In this study, commercial porous stainless steel media filters (240. μm thick) were used as a backbone to prepare hybrid ion-exchange membranes by casting ion-exchange materials within the porous metal structure. The surface of the metal reinforcements was modified by plasma treatment prior to sol-gel silane grafting to improve the interface between the metal and the ion-exchange resins. The morphology of novel hybrid materials and the interface between the metal fibers and the ion-exchange material have been characterized using techniques such as scanning electron microscopy and FTIR mapping. The thickness of the silane coating was found to lie between 1 and 2. μm while water contact angle tests performed on membrane surfaces and corrosion test behaviors revealed the formation of a thin passivating oxide layer on the material surfaces providing anchoring for the silane grafting and adequate surface energy for the proper incorporation of the ion-exchange material. The hybrid membranes desalination performance were then tested in a bench top electro-dialysis cell over a range of flow rate, current densities and salt concentration conditions to evaluate the ability of the novel hybrid materials to desalinate model streams. The performance of the hybrid membranes were benchmarked and critically compared against commercially available membranes (Selemion™). Although the salt transfer kinetics across the hybrid ion-exchange composite membranes were shown to be comparable to that of the commercial membranes, the low porosity of the stainless steel reinforcements, around 60%, was shown to impede absolute salt permeations. The hybrid ion-exchange membranes were however found to be competitive at low current density and low flow velocity desalination conditions.

Qualitative spectroscopic characterization of the matrix-silane coupling agent interface across metal fibre reinforced ion exchange resin composite membranes

The characterization of novel metal reinforced electro-dialysis ion exchange membranes, for water desalination, by attenuated total reflectance Fourier transform infrared spectroscopy mapping is presented in this paper. The surface of the porous stainless steel fibre meshes was treated in order to enhance the amount of surface oxide groups and increase the material hydrophilicity. Then, the metal membranes were functionalized through a sol-gel reaction with silane coupling agents to enhance the affinity with the ion exchange resins and avoid premature metal oxidation due to redox reactions at the metal-polymer interface. Polished cross sections of the composite membranes embedded into an epoxy resin revealed interfaces between metallic frameworks and the silane layer at the interface with the ion exchange material. The morphology of the metal-polymer interface was investigated with scanning electron microscopy and Fourier transform infrared micro-spectroscopy. Fourier transform infrared mapping of the interfaces was performed using the attenuated total reflectance mode on the polished cross-sections at the Australian Synchrotron. The nature of the interface between the metal framework and the ion exchange resin was shown to be homogeneous and the coating thickness was found to be around 1 μm determined by Fourier transform infrared micro-spectroscopy mapping. The impact of the coating on the properties of the membranes and their potential for water desalination by electro-dialysis are also discussed.

Chiral trialkoxysilanols derived from terpene alcohols. Molecular structures of tris([(1S)-endo]-(-)-bornoxy)silanol and tetrakis((-)-menthoxy)silane

Terpene alcohols (−)-menthol and [(1S)-endo]-(−)-borneol react with SiCl₄ in the presence of base to give (MenO)₃SiCl (1) and (BorO)₃SiCl (2) in high yields. Hydrolysis of 1 yields (MenO)₃SiOH (4) and (MenO)₄Si (3). Hydrolysis of 2 yields only (BorO)₃SiOH (5). The crystal structures of 3 and 5 are reported.

The normative distribution of chest tube drainage volume after coronary artery bypass grafting

Background
Little evidence exists to describe expected volumes of chest tube (CT) drainage after coronary artery bypass grafting (CABG).

Objectives
The study objective was to map the trajectory of CT drainage volumes from insertion to removal after CABG.

Design

This was a retrospective, descriptive study.
Patients
The study included 239 patients who underwent CABG at a single metropolitan hospital in Melbourne, Australia.

Results
The sample (N = 234), aged 68.7 years (standard deviation [SD] 9.9), was predominantly male (N = 185, 79.1%). The mean duration of CT insertion was 45.2 hours (SD 26.7), and total drainage volume was 1300.6 mL (SD 763.8). Drainage volumes plateau to 31 mL per hour, 8 hours after surgery. From 24 to 48 hours, the mean drainage was 21 mL per hour. Drainage volumes varied between genders.

Conclusions
Evidence of similar drainage patterns in other populations is difficult to locate. If the pattern of drainage shown in this study is consistent, experimental intervention studies comparing standard removal time and earlier removal are recommended. If not, prospective collection of relevant preoperative, intraoperative, and postoperative factors across multiple sites is necessary to determine which patient or practice variations influence CT drainage patterns after CABG.

Impaction bone grafting of the glenoid in revision shoulder arthroplasty : classification, technical description and early results

Background Glenoid component fixation remains an issue in the long-term survival of total shoulder arthroplasty. As a consequence revision of the glenoid component is becoming increasingly more common and reconstructive techniques to preserve and restore bone stock are becoming more important.

Methods In this article we describe the combined technique of impaction grafting and glenoid component exchange together with a classification of the glenoid defect with a report on four sequential cases in patients with rheumatoid arthritis with an average age of 56 years. The minimum follow-up was 34 months (range 34 months to 62 months).

Results Patients reported excellent pain relief and some improvement in motion and function. The complication rate remains low. Radiological assessment using tomograms showed good incorporation of the bone graft and minimal signs of glenoid loosening.

Conclusion The results of this study confirm that at least in the short term impaction grafting techniques used to reconstitute the glenoid in revision surgery can be successful.

Reinforcement of natural rubber with core-shell structure silica-poly(Methyl Methacrylate) nanoparticles

A highly performing natural rubber/silica (NR/SiO2) nanocomposite with a SiO2 loading of 2 wt% was prepared by combining similar dissolve mutually theory with latex compounding techniques. Before polymerization, double bonds were introduced onto the surface of the SiO2 particles with the silane-coupling agent. The core-shell structure silica-poly(methyl methacrylate), SiO2-PMMA, nanoparticles were formed by grafting polymerization of MMA on the surface of the modified SiO2 particles via in situ emulsion, and then NR/SiO2 nanocomposite was prepared by blending SiO2-PMMA and PMMA-modified NR (NR-PMMA). The Fourier transform infrared spectroscopy results show that PMMA has been successfully introduced onto the surface of SiO2, which can be well dispersed in NR matrix and present good interfacial adhesion with NR phase. Compared with those of pure NR, the thermal resistance and tensile properties of NR/SiO2 nanocomposite are significantly improved.

Robust, electro-conductive, self-healing superamphiphobic fabric prepared by one-step vapour-phase polymerisation of poly(3,4-ethylenedioxythiophene) in the presence of fluorinated decyl polyhedral oligomeric silsesquioxane and fluorinated alkyl silane

A robust, electrically conductive, superamphiphobic fabric was prepared by vapour-phase polymerisation of 3,4-ethylenedioxythiophene (EDOT) on fabric in the presence of fluorinated decyl polyhedral oligomeric silsesquioxane (FD-POSS) and a fluorinated alkyl silane (FAS). The coated fabric had contact angles of 169° and 156° respectively to water and hexadecane, and a surface resistance in the range of 0.8–1.2 kΩ o⁻¹ . The incorporation of FD-POSS and FAS into the PEDOT layer showed a very small influence on the conductivity but improved the washing and abrasion stability considerably. The coated fabric can withstand at least 500 cycles of standard laundry and 10000 cycles of abrasion without apparently changing the superamphiphobicity, while the conductivity only had a small reduction after the washing and abrasion. More interestingly, the coating had a self-healing ability to auto-repair from chemical damages to restore the liquid repellency.

Robust, self-healing superamphiphobic fabrics prepared by two-step coating of fluoro-containing polymer, fluoroalkyl silane, and modified silica nanoparticles

A robust, superamphiphobic fabric with a novel self-healing ability to autorepair from chemical damage is prepared by a two-step wet-chemistry coating technique using an easily available material system consisting of poly(vinylidene fluoride-co-hexafluoropropylene), fluoroalkyl silane, and modified silica nanoparticles. The coated fabrics can withstand at least 600 cycles of standard laundry and 8000 cycles of abrasion without apparently changing the superamphiphobicity. The coating is also very stable to strong acid/base, ozone, and boiling treatments. After being damaged chemically, the coating can restore its super liquid-repellent properties by a short-time heating treatment or room temperature ageing. This simple but novel and effective coating system may be useful for the development of robust protective clothing for various applications.

A systematic study of carbon fibre surface grafting via in situ diazonium generation for improved interfacial shear strength in epoxy matrix composites

A recently established means of surface functionalization of unsized carbon fibres for enhanced compatibility with epoxy resins was optimised and evaluated using interfacial shear stress measurements. Interfacial adhesion has a strong influence on the bulk mechanical properties of composite materials. In this work we report on the optimisation of our aryl diazo-grafting methodology via a series of reagent concentration studies. The fibres functionalised at each concentration are characterised physically (tensile strength, modulus, coefficient of friction, and via AFM), and chemically (XPS). The interfacial shear strength (IFSS) of all treated fibres was determined via the single fibre fragmentation test, using the Kelly-Tyson model. Large increases in IFSS for all concentrations (28-47%) relative to control fibres were observed. We show that halving the reagent concentration increased the coefficient of friction of the fibre and the interfacial shear strength of the composite while resulting in no loss of the key performance characteristics in the treated fibre.

Influence of non-hydrolysable groups in silane precursor on pore dimension and photochromic properties of sol-gel silica embedded with a spirooxazine dye

In this work, silica embedded with a spirooxazine dye was prepared by hydrolysis of silanes that bear a nonhydrolyzable group of different structures through a sol-gel route in the presence of a spirooxazine dye, and the pore dimension and photochromic properties of photochromic silica coatings on fabric were studied. The pore dimension in the silica was examined by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and nitrogen adsorption porosimetry. The SAXS results revealed that the distance between pores was in the range between 0.8 nm and 1.9 nm and it increased with increasing the size of the non-hydrolyzable group. Pore size measured by nitrogen adsorption porosimetry was in the range of 2.1-2.7 nm. The photochromic optical absorption was influenced mainly by the hydrophobicity of the non-hydrolyzable groups, while the color changing rates were influenced by the steric effect of the non-hydrolyzable groups and their interaction with the dye.

Ischaemic heart disease and Australian immigrants: the influence of birthplace and language skills on treatment and use of health services

Admission rates for ischaemic heart disease (IHD), and the use of invasive cardiovascular procedures, separation mode and length of stay (LOS) were compared between Australians from non-English speaking background (NESB; n=8627) and English speaking background (ESB; n=13162) aged 20 years and over admitted to Victorian urban public hospitals. The study covered the period from 1993 to 1998. It was found that, compared with their ESB counterparts, the incidence of admission for acute myocardial infarction was significantly higher for NESB men and women before and after controlling for confounding factors. The age-adjusted ratios for NESB women compared with their ESB counterparts ranged from 1.23 to 1.89 for cardiac catheterisation, from 0.23 to 0.27 for percutaneous transluminal coronary angioplasty (PTCA), and from 1.04 to 1.80 for coronary artery bypass grafting (CABG).
Procedure rates were comparable in men for cardiac catheterisation and CABG but higher for PTA rates in NESB men (OR: 1.29, 95%CI: 1.11-1.50) than their ESB counterparts. Both NESB men (β=0.04, 95%CI: 0.01-0.07) and women (β=0.03, 95%CI: 0.02-0.08) experienced significantly longer hospital stays than their ESB counterparts. These findings indicate there may be systematic differences in patients’ treatment and service utilisation in Victorian public hospitals. The extent to which physicians’ bias and
patients’ choice could explain these differences requires further investigation.