Graphene Oxide Membrane Dehydration via Pervaporation
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Solution Overview
Problem
Current dehydration methods using hydrophilic membranes, such as zeolites and polymeric membranes, face limitations in stability, selectivity, energy efficiency, and cost-effectiveness, particularly in removing water from gas mixtures and liquids across a wide range of conditions.
Innovation Solution
The use of graphene oxide membranes supported by porous materials, which allow selective permeation of water while being impermeable to other gases and liquids, leveraging the unique structure of graphene oxide for efficient dehydration through pervaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If zeolite membranes are used for dehydration, then water removal capability is improved, but membrane stability and durability deteriorate due to dissolution in acidic conditions and formation problems
Solution Approach 1:
The patent uses composite materials by combining graphene oxide with porous supports (such as alumina or polyester substrates) to create a stable membrane structure. The porous support provides mechanical strength and stability while the graphene oxide layer provides selective water permeability, resolving the contradiction between water removal capability and membrane stability.
Solution Approach 2:
The patent employs porous materials as the support structure for the graphene oxide membrane. The porous substrate (e.g., alumina with pore sizes of 0.1-10 micrometers) provides both mechanical stability and facilitates water transport through capillary action, maintaining reliability while enabling high productivity.
2Productivity
If conventional hydrophilic membranes are used, then water separation is achieved, but selectivity deteriorates compared to the desired high selectivity
Solution Approach 1:
The patent uses thin films of graphene oxide (with thicknesses of 10-1000 nanometers) deposited on porous supports. This thin film structure provides exceptional selectivity for water molecules while maintaining high flux, achieving both high separation efficiency and high selectivity that conventional membranes cannot attain.
Solution Approach 2:
The patent changes the physical and chemical parameters of the membrane by using oxidized graphite (graphene oxide) with specific interlayer spacing and functional groups. This parameter change enables the membrane to achieve superior water selectivity through size exclusion and hydrogen bonding interactions, outperforming conventional hydrophilic membranes.
3Productivity
If distillation is used for dehydration, then water removal is effective, but energy consumption increases due to harsh conditions required
Solution Approach 1:
The patent replaces the thermal field (distillation) with a membrane separation field. Instead of using heat and mass transfer through vaporization, the system uses selective permeation through the graphene oxide membrane, eliminating the need for high temperatures and significantly reducing energy consumption while maintaining effective water removal.
Solution Approach 2:
The patent utilizes the phase transition properties of water through capillary condensation and evaporation in the porous support structure. Water molecules condense in the pores of the support and evaporate on the permeate side, enabling dehydration at much lower temperatures than distillation while maintaining effectiveness.
4Ease of manufacture
If polymeric membranes are used, then ease of manufacture is improved, but selectivity deteriorates compared to zeolite membranes
Solution Approach 1:
The patent creates a composite structure combining the ease of polymeric substrate manufacturing with the superior selectivity of graphene oxide. The porous polymer support (such as polyester) provides mechanical flexibility and ease of fabrication, while the graphene oxide coating layer provides high water selectivity, achieving both ease of manufacture and high separation precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The graphene oxide membrane system provides enhanced selectivity, durability, and energy efficiency for dehydration, allowing for the effective separation of water from gas and liquid mixtures, with potential applications in gas drying, detector systems, and concentration processes.
Implementation Method 1
Pervaporation consists of two basic steps: permeation of the permeate through the membrane and evaporation of the permeate from the other side of the membrane
Implementation Method 2
permeation of the permeate through the membrane
Implementation Method 3
graphene oxide membranes which are effectively composed of graphene oxide having a thickness around 1 μm are permeable to water
Data Source
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AI summary
This invention relates to uses of graphene oxide, and in particular graphene oxide on a porous support, and a membrane comprising these materials. This invention also relates to methods of dehydration, which include vapour phase separation and pervaporation. Pervaporation is a method of separating mixtures of liquids using a membrane. Pervaporation consists of two basic steps: permeation of the permeate through the membrane and evaporation of the permeate from the other side of the membrane. Pervaporation is a mild which can be used to separate components which would not survive the comparatively harsh conditions needed for distillation (high temp, and/or low pressure).