Multilayer Mixed Matrix Membrane for Membrane Distillation
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Solution Overview
Problem
Membrane distillation processes face challenges with lower flux and membrane wetting issues due to inadequate membrane design and module design, hindering commercialization, especially in large-scale applications.
Innovation Solution
The development of novel techniques for manufacturing flat-sheet and hollow-fibre composite multilayer polymeric and mixed matrix membranes with improved layer characteristics, and a plate-and-frame membrane module design that enhances flow hydrodynamics, heat transfer coefficients, and minimizes boundary layer resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophobic membranes are used for membrane distillation, then membrane wetting is prevented, but permeate flux is reduced
Solution Approach 1:
The patent applies composite materials by combining hydrophobic polymers (PTFE, PVDF, PP) with hydrophilic polymers (cellulose acetate, polyamide, polysulfone) to create multilayer composite membranes. The hydrophobic layer prevents wetting while the hydrophilic layer enhances flux, resolving the contradiction between durability and productivity.
Solution Approach 2:
The membrane is segmented into multiple functional layers with distinct properties. The hydrophobic layer provides wetting resistance, while the hydrophilic layer provides high flux. This segmentation allows each layer to optimize its specific function without compromising the other.
2Ease of manufacture
If conventional single-layer membranes are used, then manufacturing is simple, but both flux and durability are insufficient
Solution Approach 1:
The membrane structure is segmented into multiple layers, each with specific functions. While manufacturing becomes slightly more complex, the systematic approach to layer construction provides superior flux and durability compared to single-layer membranes.
Solution Approach 2:
By using composite materials with different properties in different layers, the patent achieves both high flux and durability, overcoming the limitations of conventional single-layer membranes while maintaining reasonable manufacturing complexity.
3Productivity
If membrane layers are optimized for high flux, then permeate flux increases, but membrane wetting resistance decreases
Solution Approach 1:
The membrane is divided into distinct layers where the hydrophobic layer specifically addresses wetting resistance while the hydrophilic layer addresses flux. This segmentation allows independent optimization of each function without compromise.
Solution Approach 2:
The composite structure combines materials with complementary properties: hydrophobic materials for wetting resistance and hydrophilic materials for high flux. This composite approach resolves the contradiction by allowing both properties to coexist in different layers.
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 new membrane preparation techniques and module design significantly improve permeate flux and membrane durability, achieving higher desalination rates and heat transfer efficiency, such as up to 142 kg/m²h seawater desalination flux and high heat transfer coefficients, overcoming previous limitations.
Implementation Method 1
As the process is non-isothermal, vapour molecules migrate through the membrane pores from the warm (feed) side to the cold (permeate) side
Implementation Method 2
The main requirement of the MD membrane is that the pores must not be wetted and only vapour and/or gas is present. This is limiting the membrane distillation membranes choice into those made of hydrophobic materials
Implementation Method 3
the concepts of hydrophobic/hydrophilic composite polymeric and mixed matrix membranes for MD were firstly presented. It was shown that these types of membranes satisfy all the requirements of higher permeate flux MD membranes
Implementation Method 4
MD is a thermally driven process in which a microporous membrane acts as a physical support separating a warm solution from a cooler chamber
Data Source
AI summary
Provided is a method of manufacturing a multilayer mixed matrix membrane which includes providing a support layer, casting a hydrophilic layer on a surface of the support layer, casting a hydrophobic layer on the hydrophilic layer, and allowing the layers to form a multilayer mixed matrix membrane. Also provided is a method of manufacturing a hollow fiber composite matrix membrane which includes providing a first solution having a hydrophilic polymer, providing a second solution having a hydrophobic polymer, and extruding the first and second solutions to form a multilayer hollow fiber composite matrix membrane. Additionally, a plate-and-frame membrane module for direct contact membrane distillation using a multilayer mixed matrix membrane is provided. The plate-and-frame membrane module includes a feed inlet capable of distributing process solution throughout the membrane module, a permeate inlet capable of distributing process solution throughout the membrane module, a tortuous promoter comprising multiple flow channels, a feed outlet, and a permeate outlet.