MoS2 Membranes with Covalent Groups for Dry Filtration
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Solution Overview
Problem
Current desalination technologies, particularly reverse osmosis, require high energy consumption and involve complex processing steps due to the need for precise control of membrane hydration and drying to maintain permeability, limiting their efficiency and practicality for large-scale water treatment.
Innovation Solution
Development of molybdenum disulfide (MoS2) membranes with covalently bound hydrophilic organic functional groups that maintain optimal interlayer spacing and prevent irreversible restacking, allowing for reusable membranes that remain permeable even when dry, thus reducing energy requirements and simplifying the desalination process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional reverse osmosis membranes are used, then desalination can be performed, but energy consumption increases by an order of magnitude compared to freshwater treatment
Solution Approach 1:
The patent employs restacked two-dimensional materials with precisely controlled interlayer spacing to create nanometer-scale channels that function as molecular sieves. The porous structure allows selective passage of water molecules while blocking ions, achieving high water flux with minimal energy input by exploiting size-based exclusion rather than high-pressure forcing.
Solution Approach 2:
The invention uses composite two-dimensional material structures combining hydrophilic surfaces for water attraction with precisely engineered interlayer spacings for ion exclusion. This composite approach optimizes both water permeability and salt rejection, dramatically reducing the energy required for desalination compared to conventional single-material membranes.
2Productivity
If graphene oxide membranes are used, then high water flux is achieved, but the membranes swell and disintegrate when soaked in water
Solution Approach 1:
The patent modifies the interlayer spacing parameter of two-dimensional materials to maintain optimal nanometer-scale channels while preventing the swelling and disintegration observed in graphene oxide. By precisely controlling the spacing through restacking techniques and chemical functionalization, the membrane maintains structural integrity in water while preserving high water flux capabilities.
Solution Approach 2:
The invention combines two-dimensional materials with specific surface chemistry properties to create composite structures that resist swelling. The use of hydrophobic or chemically cross-linked interlayer regions prevents water-induced expansion while maintaining hydrophilic channels for water transport, thereby ensuring both high productivity and reliability.
3Reliability
If ce-MoS2 membranes are used, then structural stability is improved, but the association between hydration-dependent structure and filtration performance remains underexplored
Solution Approach 1:
The patent designs ce-MoS2 membranes with inherent hydration-resistance through chemical functionalization and controlled interlayer spacing, eliminating the need for external hydration control mechanisms. The membrane structure self-regulates to maintain optimal performance across varying humidity conditions, simplifying operation while preserving structural stability.
Solution Approach 2:
The invention modifies the chemical and physical parameters of ce-MoS2, including surface functionalization and interlayer spacing, to reduce hydration dependence. These parameter changes enable the membrane to maintain consistent filtration performance without requiring precise hydration control, thereby improving ease of operation while retaining structural reliability.
4Quantity of substance
If membrane interlayer spacing is reduced for ion exclusion, then salt selectivity improves, but water flux decreases
Solution Approach 1:
The patent employs precisely engineered nanometer-scale porous channels with interlayer spacing optimized to allow water molecules to pass while excluding hydrated ions. The pore size is carefully controlled to exploit the size difference between water molecules and hydrated ions, achieving high ion rejection without significantly reducing water flux.
Solution Approach 2:
The invention creates local variations in surface chemistry and interlayer spacing to optimize both ion exclusion and water transport. Hydrophilic surface regions attract and facilitate water passage, while specific interlayer spacing zones provide steric hindrance to ions, thereby achieving high salt selectivity without compromising water flux.
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 MoS2 membranes achieve high water flux and ion rejection while eliminating the need for precise hydration control, enhancing the efficiency and practicality of desalination by maintaining permeability after drying, thereby reducing energy consumption and operational complexity.
Implementation Method 1
The channel width of restacked ce-MoS2 is on the appropriate length scale for size-based exclusion of ions while facilitating high water flux
Implementation Method 2
A result of its mild hydrophilicity, water molecules interact weakly with the ce-MoS2 surface. This weak interaction leads to a higher water flux
Implementation Method 3
moisture-cured polyurethane adhesives and sealants comprising a mixture of isocyanate-terminated polymer and crosslinker, wherein the isocyanate-terminated polymer and the crosslinker are coupled to one another through covalent bonds
Implementation Method 4
Restacked two dimensional (2D) materials... comprise a new class of nanofiltration membranes that show great promise as efficient separators of ions and small molecules from water
Data Source
AI summary
Molybdenum disulfide membranes for ionic and/or molecular filtration applications are provided. The membranes have high separation performance, including high water flux and high molecule and/or ion rejection, and do not need to be stored in a hydrated condition in order to enable their reuse. The membranes are based on stacked MoS2 sheets having small hydrophilic organic functional groups covalently bound thereto.