scholarly journals A Review on Reverse Osmosis and Nanofiltration Membranes for Water Purification

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1252 ◽  
Author(s):  
Yang ◽  
Zhou ◽  
Feng ◽  
Rui ◽  
Zhang ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Water Purification ◽  
Membrane Separation ◽  
Cost Effective ◽  
Ceramic Membranes ◽  
High Water ◽  
Polymeric Membranes ◽  
Inorganic Membrane ◽  
Inorganic Membranes ◽  
Research Findings

Sustainable and affordable supply of clean, safe, and adequate water is one of the most challenging issues facing the world. Membrane separation technology is one of the most cost-effective and widely applied technologies for water purification. Polymeric membranes such as cellulose-based (CA) membranes and thin-film composite (TFC) membranes have dominated the industry since 1980. Although further development of polymeric membranes for better performance is laborious, the research findings and sustained progress in inorganic membrane development have grown fast and solve some remaining problems. In addition to conventional ceramic metal oxide membranes, membranes prepared by graphene oxide (GO), carbon nanotubes (CNTs), and mixed matrix materials (MMMs) have attracted enormous attention due to their desirable properties such as tunable pore structure, excellent chemical, mechanical, and thermal tolerance, good salt rejection and/or high water permeability. This review provides insight into synthesis approaches and structural properties of recent reverse osmosis (RO) and nanofiltration (NF) membranes which are used to retain dissolved species such as heavy metals, electrolytes, and inorganic salts in various aqueous solutions. A specific focus has been placed on introducing and comparing water purification performance of different classes of polymeric and ceramic membranes in related water treatment industries. Furthermore, the development challenges and research opportunities of organic and inorganic membranes are discussed and the further perspectives are analyzed.

Inorganic Membranes for Hydrogen Production from the Water-Gas Shift Reaction: Materials, Reactor Design, and Simulation

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Li Ping Ding ◽  
Zehong Wang
Keyword(s):  
Membrane Reactor ◽  
Ceramic Membranes ◽  
Reactor Design ◽  
Membrane Reactors ◽  
Water Gas Shift ◽  
Inorganic Membrane ◽  
Inorganic Membranes ◽  
Separation And Purification ◽  
Wgs Reaction ◽  
Water Gas

Inorganic membranes for gas separation and purification have attracted great research interest. One application utilizing these materials is for H2 production from the water-gas shift reactions (WGS). The exothermic, reversible WGS reaction is controlled by thermodynamic equilibrium and exhibits decreased conversion with increasing temperatures. It is envisaged that the reaction conversion will surpass the equilibrium value if the reaction is conducted in a hydrogen-permselective membrane reactor, where the hydrogen product can be continuously removed from the reactor to shift the reaction equilibrium. In this article, the most recent development on material synthesis and fabrication of microporous ceramic membranes and dense palladium-based metal membranes are firstly reviewed according to their performance for H2 permeance and permselectivity over slightly larger molecules. The modification methods for improving membrane structure integrity, hydrophobicity, and stability at high temperature operation are also discussed. Subsequently, inorganic membrane reactors for the WGS reaction are evaluated in terms of CO conversion, hydrogen purity and operation parameters. Finally, modeling on gas transport through inorganic membranes and simulation of membrane reactors are discussed. By comparing the performance of various membranes, future prospective and improvement on membrane preparation and membrane reactor design are proposed.

Recent Research in Catalytic Inorganic Membrane Reactors

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Anthony G. Dixon
Keyword(s):  
Membrane Separation ◽  
Polymeric Materials ◽  
Chemical Reactor ◽  
Product Formation ◽  
Review Literature ◽  
Inorganic Materials ◽  
Membrane Reactors ◽  
Inorganic Membrane ◽  
Inorganic Membranes ◽  
Present Contribution

The two most important, and often the most expensive, steps in a chemical process are usually the chemical reactor and the separation of the product stream. Both the process economics and the efficient use of natural resources could be improved by the combination of these two operations into a single unit operation, leading to potential savings in energy and reactant consumption and reduced by-product formation. One promising way to accomplish this combination is the use of membrane separation and catalytic reaction together in a multifunctional reactor. Until relatively recently, the use of membranes was restricted to low temperature processes with mild chemical environments, which could be tolerated by polymeric materials. Recent advances in inorganic materials have expanded the range of membrane use, to include high temperature and chemically harsh environments. This has allowed inorganic membranes to be integrated into catalytic reactors. This area was reviewed previously by the present author (Dixon, 1999). The present contribution seeks to review literature and new developments in the succeeding four and a half year period, since the end of 1998. Research directions that were previously considered promising are re-evaluated here, and new ideas since then are presented.

scholarly journals Graphene Membranes: From Reverse Osmosis to Gas Separation

2021 ◽  
Vol 8 (2) ◽  
pp. 1-27
Author(s):  
de Souza Figueiredo Katia Cecilia ◽  
de Jesus Barcelos Gustavo Feliciano ◽  
Ferlauto André Santarosa
Keyword(s):  
Reverse Osmosis ◽  
Membrane Separation ◽  
Skin Layer ◽  
Polymeric Membranes ◽  
Water Desalination ◽  
Innovative Technology ◽  
Separation Processes ◽  
Carbon Dioxide Separation ◽  
Current State ◽  
Graphene Membranes

Graphene membrane is a promising technology to help both carbon dioxide separation from flue gas and water desalination. This work reported the importance of membrane separation processes, the evolution of polymeric membranes before the discovery of graphene and how this material fits into this scenario. In addition, reverse osmosis and gas separations have been discussed as promising methods to reduce the occurrence of freshwater scarcity events and slow global warming. For all these separation techniques, the current state of graphene membranes technology and what advances might be brought by such one atom thick skin layer were presented, as well as the results of theoretical and experimental research. Finally, the challenges that still need to be overcome by this innovative technology as well as the perspectives were shown.

Polymeric Membranes for Water Purification and Gas Separation

2021 ◽  
Keyword(s):  
Reverse Osmosis ◽  
Gas Separation ◽  
Water Purification ◽  
Forward Osmosis ◽  
Synthetic Polymers ◽  
Polymeric Membranes ◽  
Inorganic Pollutants ◽  
Separation Of Gases

Various organic and synthetic polymers are important materials for the removal of organic and inorganic pollutants from wastewater and the separation of gases. The book discusses various types of membranes for microfiltration, ultrafiltration, nanofiltration, reverse osmosis, forward osmosis etc. A number of nanomaterials are available for the modification of polymeric membranes.

scholarly journals Transport Behavior in Polymer-Inorganic Membrane: A Review

2017 ◽  
Vol 19 (1) ◽  
Author(s):  
N. N. Nik Mustofar ◽  
Juhana Jaafar ◽  
M. Aziz ◽  
A. F. Ismail ◽  
Mukhlis A. Rahman ◽  
...  
Keyword(s):  
Polymer Membranes ◽  
Composite Membranes ◽  
Polymeric Membranes ◽  
Inorganic Membrane ◽  
Methanol Permeability ◽  
Inorganic Membranes ◽  
Transport Behavior ◽  
Transport Behaviour ◽  
Significant Achievement ◽  
Inorganic Composite

The polymer–inorganic composite membrane has emerged as an alternative to improve the separation properties of polymer membranes because they possess properties of both organic and inorganic membranes such as good hydrophilicity, selectivity, permeability, mechanical strength, and thermal and chemical stability. A unique combination of organic and inorganic properties is believed could overcome the limitations of the pure polymeric membranes. Transport behavior of gases, vapours and liquids through polymer membranes are important in ultrafiltration, nanofiltration, pervaporation, gas separation and fuel cell applications. A better understanding of transport mechanisms in polymer-inorganic composite membranes is highly important in order to achieve significant achievement in the respective applications. This article provides a detailed review of current research in the field of transport phenomena on the transport behaviour of proton and methanol through the polymeric-inorganic by means of proton conductivity and methanol permeability.

Fouling Is the Beginning: Upcycling Biopolymer-Fouled Substrates for Fabricating High-Permeance Thin-Film Composite Polyamide Membranes

2020 ◽  
Author(s):  
Ruobin Dai ◽  
Hongyi Han ◽  
Tianlin Wang ◽  
Jiayi Li ◽  
Chuyang Y. Tang ◽  
...  
Keyword(s):  
Thin Film ◽  
High Pressure ◽  
End Of Life ◽  
Water Purification ◽  
Low Pressure ◽  
Polymeric Membranes ◽  
Membrane Recycling ◽  
Film Composite ◽  
Thin Film Composite ◽  
First Time

Commercial polymeric membranes are generally recognized to have low sustainability as membranes need to be replaced and abandoned after reaching the end of their life. At present, only techniques for downcycling end-of-life high-pressure membranes are available. For the first time, this study paves the way for upcycling fouled/end-of-life low-pressure membranes to fabricate new high-pressure membranes for water purification, forming a closed eco-loop of membrane recycling with significantly improved sustainability.

scholarly journals Removal of heavy metal ions from wastewater: a comprehensive and critical review

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Naef A. A. Qasem ◽  
Ramy H. Mohammed ◽  
Dahiru U. Lawal
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Large Volume ◽  
Heavy Metal Ions ◽  
Membrane Separation ◽  
Cost Effective ◽  
Operating Conditions ◽  
Future Research ◽  
Sludge Formation ◽  
Metals Removal

AbstractRemoval of heavy metal ions from wastewater is of prime importance for a clean environment and human health. Different reported methods were devoted to heavy metal ions removal from various wastewater sources. These methods could be classified into adsorption-, membrane-, chemical-, electric-, and photocatalytic-based treatments. This paper comprehensively and critically reviews and discusses these methods in terms of used agents/adsorbents, removal efficiency, operating conditions, and the pros and cons of each method. Besides, the key findings of the previous studies reported in the literature are summarized. Generally, it is noticed that most of the recent studies have focused on adsorption techniques. The major obstacles of the adsorption methods are the ability to remove different ion types concurrently, high retention time, and cycling stability of adsorbents. Even though the chemical and membrane methods are practical, the large-volume sludge formation and post-treatment requirements are vital issues that need to be solved for chemical techniques. Fouling and scaling inhibition could lead to further improvement in membrane separation. However, pre-treatment and periodic cleaning of membranes incur additional costs. Electrical-based methods were also reported to be efficient; however, industrial-scale separation is needed in addition to tackling the issue of large-volume sludge formation. Electric- and photocatalytic-based methods are still less mature. More attention should be drawn to using real wastewaters rather than synthetic ones when investigating heavy metals removal. Future research studies should focus on eco-friendly, cost-effective, and sustainable materials and methods.

Leachate Minimization by Reverse Osmosis

1992 ◽  
Vol 25 (3) ◽  
pp. 117-120 ◽  
Author(s):  
T. Bilstad ◽  
M. V. Madland
Keyword(s):  
Reverse Osmosis ◽  
Suspended Solids ◽  
Membrane Separation ◽  
Water Phase ◽  
Major Portion ◽  
Tubular Type ◽  
Iron Copper ◽  
Copper Chromium ◽  
Direct Discharge

Leachates from chemical and domestic landfills are defined as hazardous wastewater. Quantitative and qualitative control of leachate can be performed by membrane separation of the total produced leachate volume. Dissolved and suspended solids in the leachate are removed from the major portion of the water phase and either returned to the landfill or further treated. The particle - free permeate meets the effluent requirements for direct discharge to virtually any watercourse. An untreated leachate flow is concentrated thirteen times by tubular type reverse osmosis. The separation efficiencies are 99% for iron, copper, chromium and zinc. For suspended solids the removal is 100%.

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