Separation of carbon dioxide and nitrogen gases using novel composite membranes

2017 ◽  
Vol 95 (1) ◽  
pp. 57-67 ◽  
Author(s):  
A. Uma Maheswari ◽  
K. Palanivelu
Keyword(s):  
Power Plants ◽  
Composite Membranes ◽  
Environmental Issue ◽  
Cross Linking ◽  
Gas Mixture ◽  
Loading Capacity ◽  
Amine Molecule ◽  
Species Effect ◽  
Optimized Conditions ◽  
Urgent Action

Global warming is the major environmental issue caused by greenhouse gases, especially CO2. This demands urgent action to reduce or offset CO2 emission from power plants, which could be done using facilitated transport membranes (FTMs). In this context, CO2 selective carriers were prepared by blending polyvinyl alcohol (PVA) with three amines: ethylenediamine (EDA), diethylenetriamine (DETA), and triethylenetetramine (TETA). Then, the composite membranes were prepared using PVA–amine blend as the separation layer and ceramic candle filters as the support layer. The fabricated membrane was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Furthermore, the effect of amine species, effect of TETA concentration, cross-linking agent content, pressure difference, and the thickness of the membrane on the permeance and selectivity of CO2 over N2 were investigated. The permeance and selectivity of CO2 through the membranes were in the following order: TETA > DETA > EDA. This order is related to the number of nitrogen atoms per amine molecule, which can be correlated to loading capacity and, consequently, to amine reactivity with CO2. Under optimized conditions, for a pure gas experiment, the maximum permeance of 6.9 GPU for CO2 gas and selectivity of 50 over N2 was obtained, whereas in the CO2/N2 gas mixture, the maximum permeance of 8.6 GPU and selectivity of 98 was obtained. The membrane was found to be stable for 264 h.

scholarly journals Chemically Cross-Linked Graphene Oxide as a Selective Layer on Electrospun Polyvinyl Alcohol Nanofiber Membrane for Nanofiltration Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2867
Author(s):  
Myoung Jun Park ◽  
Grace M. Nisola ◽  
Dong Han Seo ◽  
Chen Wang ◽  
Sherub Phuntsho ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Self Assembly ◽  
Water Flux ◽  
Composite Membranes ◽  
Cross Linking ◽  
Support Surface ◽  
Eosin Y ◽  
Selective Layer ◽  
Assembly Technique

Graphene oxide (GO) nanosheets were utilized as a selective layer on a highly porous polyvinyl alcohol (PVA) nanofiber support via a pressure-assisted self-assembly technique to synthesize composite nanofiltration membranes. The GO layer was rendered stable by cross-linking the nanosheets (GO-to-GO) and by linking them onto the support surface (GO-to-PVA) using glutaraldehyde (GA). The amounts of GO and GA deposited on the PVA substrate were varied to determine the optimum nanofiltration membrane both in terms of water flux and salt rejection performances. The successful GA cross-linking of GO interlayers and GO-PVA via acetalization was confirmed by FTIR and XPS analyses, which corroborated with other characterization results from contact angle and zeta potential measurements. Morphologies of the most effective membrane (CGOPVA-50) featured a defect-free GA cross-linked GO layer with a thickness of ~67 nm. The best solute rejections of the CGOPVA-50 membrane were 91.01% for Na2SO4 (20 mM), 98.12% for Eosin Y (10 mg/L), 76.92% for Methylene blue (10 mg/L), and 49.62% for NaCl (20 mM). These findings may provide one of the promising approaches in synthesizing mechanically stable GO-based thin-film composite membranes that are effective for solute separation via nanofiltration.

scholarly journals Fabrication of Drug-Loaded Starch-based Nanofibers via Electrospinning Technique

2020 ◽  
Vol 11 (3) ◽  
pp. 10801-10811
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Poly Vinyl Alcohol ◽  
Loading Capacity ◽  
Sago Starch ◽  
Electrospinning Technique ◽  
Blending Process ◽  
Operation Parameters ◽  
Optimized Conditions ◽  
Scanning Electron

This paper reported the fabrication of starch-based nanofibers derived from various weight ratios (w:w) of native sago starch (SS) and poly (vinyl alcohol) (PVA) (0:100, 1:100, 3:100, and 5:100) using the electrospinning technique. The effects of electrospinning operation parameters on the surface morphology of SS/PVA nanofibers were observed by using Scanning Electron Microscopy (SEM). The smooth and bead-free SS/PVA nanofibers with fiber diameters within the range of 90 nm to 150 nm were produced under the optimized conditions. The paracetamol (PCM) was encapsulated into the SS/PVA nanofibers via the blending process. The SS/PVA nanofibers exhibited a maximum PCM loading capacity of 0.9573 mg.mg-1, and PCM was observed to release out from SS/PVA nanofibers slowly and steadily for 72 hours.

scholarly journals Cross-Linking With Diamine Monomers to Prepare Graphene Oxide Composite Membranes With Varying D-Spacing for Enhanced Desalination Properties

2021 ◽  
Vol 9 ◽  
Author(s):  
Hong Ju ◽  
Jinzhuo Duan ◽  
Haitong Lu ◽  
Weihui Xu
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Water Flux ◽  
Covalent Bond ◽  
Composite Membranes ◽  
Rejection Rate ◽  
High Water ◽  
Cross Linking ◽  
Separation Performance ◽  
X Ray

As a new type of membrane material, graphene oxide (GO) can easily form sub-nanometer interlayer channels, which can effectively screen salt ions. The composite membrane and structure with a high water flux and good ion rejection rate were compared by the cross-linking of GO with three different diamine monomers: ethylenediamine (EDA), urea (UR), and p-phenylenediamine (PPD). X-ray photoelectron spectroscopy (XPS) results showed that unmodified GO mainly comprises π-π interactions and hydrogen bonds, but after crosslinking with diamine, both GO and mixed cellulose (MCE) membranes are chemically bonded to the diamine. The GO-UR/MCE membrane achieved a water flux similar to the original GO membrane, while the water flux of GO-PPD/MCE and GO-EDA/MCE dropped. X-ray diffraction results demonstrated that the covalent bond between GO and diamine can effectively inhibit the extension of d-spacing during the transition between dry and wet states. The separation performance of the GO-UR/MCE membrane was the best. GO-PPD/MCE had the largest contact angle and the worst hydrophilicity, but its water flux was still greater than GO-EDA/MCE. This result indicated that the introduction of different functional groups during the diamine monomer cross-linking of GO caused some changes in the performance structure of the membrane.

Asymmetric gas mixture transport in composite membranes

2011 ◽  
Vol 168 (1-2) ◽  
pp. 223-246 ◽  
Author(s):  
V.I. Roldughin ◽  
V.M. Zhdanov
Keyword(s):  
Composite Membranes ◽  
Gas Mixture

scholarly journals BIODEGRADABLE POLYMER: A NOVEL PHARMACEUTICAL CARRIER FOR SUSTAINED RELEASE OF METRONIDAZOLE

2017 ◽  
Vol 10 (10) ◽  
pp. 136
Author(s):  
Gayathri Hariharan ◽  
Priyanka Sinha
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Sustained Release ◽  
Biodegradable Polymer ◽  
Drug Loading ◽  
Cross Linking ◽  
Loading Capacity ◽  
Flow Properties ◽  
Chitosan Microspheres

Objective: To optimize and evaluate the formulation of metronidazole (MT)-loaded chitosan microspheres and to investigate the efficiency of biodegradable polymer in developing sustained release formulation of MT to prolong the action of drug.Methods: MT microspheres were prepared using emulsion cross-linking method. Polymer-drug compatibility study was done using Fourier transform infrared. Physical characteristics were evaluated by particle size,SEM, flow properties etc. In vitro studies for evaluating drug release for MT-loaded chitosan microspheres were done by dissolution study.Results: Particle size of the formulated microspheres was found to be within the range of 110-130 μm. Flow properties of F1-F7 such as angle of repose, bulk density, and tapped density were found to be within limits. Drug entrapment efficiency was found to be better for all the formulations within the range of 74.82-84.32% w/w. Drug loading capacity was found to be in the range of 56-83.2% w/v. In vitro drug release was found to be in the range of 81.32-96.23% w/v.Conclusion: In spite of all the above results, we conclude that F5 formulation was optimized depending on the data obtained from the drug loading capacity and percentage drug release studies. F5 formulation is formulated with drug-polymer ratio 1:2 with 1% of di octyl sodium sulfo succinate and 8 ml of glutaraldehyde as a cross-linking agent.

Hot Corrosion of Alloy 617 OCC in Simulated USC Power Plant Environment

2018 ◽  
Vol 941 ◽  
pp. 1748-1753 ◽  
Author(s):  
N. Arivazhagan ◽  
P.R. Hari ◽  
M. Nageswara Rao ◽  
A.H.V. Pavan
Keyword(s):  
Hot Corrosion ◽  
Power Plants ◽  
Corrosion Behaviour ◽  
Metal Loss ◽  
Gas Mixture ◽  
Degradation Mechanisms ◽  
Fireside Corrosion ◽  
Alloy 617 ◽  
Plant Environment ◽  
Inconel 617

Alloy 617 OCC, a variant of INCONEL 617 with optimised chemical composition, has been produced in India for manufacture of superheater and reheater tubing in boilers operating in advanced ultrasupercritical (A-USC) power plants. The tubing encounters intense hot corrosion conditions during service. The present study deals with hot corrosion behaviour of 617 OCC in A-USC environment. The environment occurring in A-USC plants was simulated in the laboratory by exposing the material coated with a mixture of salts at 700°C in a flowing gas mixture. For use in A-USC boiler technology, the metal loss due to fireside corrosion of the material should be less than 2 mm in 200,000 hours. The loss obtained in the present study was nearly 5 times this value. The corrosion processes were studied using SEM/EDAX, XRD and thermogravimetry. The degradation mechanisms coming into play, disqualifying the material for use in A-USC plants, would be discussed.

scholarly journals Utilization of ash from power plants for high embankments on soft soil

2018 ◽  
Vol 239 ◽  
pp. 05017 ◽  
Author(s):  
Sanja Jocković ◽  
Veljko Pujević ◽  
Miloš Marjanović
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Soil Mechanics ◽  
Soft Soil ◽  
Physical And Mechanical Properties ◽  
Environmental Issue ◽  
Engineering Properties ◽  
Environmental Requirements ◽  
Leaching Behaviour ◽  
Railway Substructure

The ash landfills are a major environmental issue. The use of ash for the highway and railway substructure achieves a double benefit: it significantly reduces the deposited quantities of ash as well as the consumption of natural materials such as crushed stone, gravel and sand. The investigation of engineering properties of fly ash from the power plant in Serbia was conducted at the Laboratory of Soil Mechanics at the Faculty of Civil Engineering in Belgrade. Relevant physical and mechanical properties of ash and mixtures with binders (cement/lime) were investigated. The ash was also tested from the aspect of the potential environmental impact, which primarily depends on the leaching behaviour of the present trace elements. The results of the study showed that fly ash meets technical and environmental requirements and that has the potential for use in highway substructure, such as construction of embankments and stabilization of soft soils. Benefits of utilization of ash and slag was shown in the case of the construction of a high embankment on soft soil on the highway section Obrenovac-Ub in Serbia.

Preparation of PVA Nanofiltration Membrane with Good Solvent Resistance

2014 ◽  
Vol 904 ◽  
pp. 71-73
Author(s):  
Jian Dong Zhang ◽  
Li Wang
Keyword(s):  
Reaction Time ◽  
Composite Membrane ◽  
Cross Linking ◽  
Nanofiltration Membrane ◽  
Solvent Resistance ◽  
Optimized Conditions ◽  
Preparation Parameter

Polyvinylalcohol (PVA) with good solvent resistance was used in preparation of nanofiltration membrane. The preparation parameter such as PVA concentration, cross-linking agent concentration and reaction time are studied in detail. When the composite membrane was prepared under optimized conditions and tested at 0.4 MPa and 20 °C, the flux of the NF membrane was about 15 L/m2h and the Na2SO4 rejection of it was about 53.3%.

Effect of Cross-Linking Agent Chemistry and Coating Conditions on Physical, Chemical, and Separation Properties of PVA-Psf Composite Membranes

2013 ◽  
Vol 49 (1) ◽  
pp. 22-29 ◽  
Author(s):  
Derrick S. Dlamini ◽  
Jinwen Wang ◽  
Ajay K. Mishra ◽  
Bhekie B. Mamba ◽  
Eric M. V. Hoek
Keyword(s):  
Composite Membranes ◽  
Cross Linking ◽  
Physical Chemical
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