Ceramic Nanofiltration Membrane with Pore-Grafted Polymer Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing nanofiltration membranes, primarily polymeric, are not suitable for high-temperature applications due to their limited thermal stability, restricting their use in chemical processes requiring resistance to temperatures above 100°C.
Innovation Solution
A ceramic nanofiltration membrane is developed with a ceramic backbone and a mixed ceramic/polymeric nanofiltration layer, utilizing a Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) process to graft polymers within the mesoporous layer of titanium oxide or zirconium oxide, while keeping the ceramic backbone free of polymer, enhancing thermal resistance and control over polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric nanofiltration membranes are used, then good filtration performance is achieved, but thermal stability deteriorates making them unsuitable for high-temperature applications
Solution Approach 1:
The patent creates a hybrid nanofiltration membrane combining polymeric nanofiltration layer with ceramic support structure. The polymeric layer provides excellent filtration performance while the ceramic backbone delivers high thermal stability, allowing the composite membrane to operate at temperatures above 100°C that would degrade purely polymeric membranes.
Solution Approach 2:
The patent applies different materials to different parts of the membrane structure: the nanofiltration layer is made of polymer for optimal separation performance, while the backbone support is made of ceramic for thermal stability. This local differentiation of material properties allows each component to fulfill its specific function without compromise.
2Temperature
If polymer is grown in the mesoporous layer through grafting, then thermal resistance is improved, but polymerization control becomes difficult leading to unwanted polymer in the backbone layer
Solution Approach 1:
The patent introduces anchoring groups specifically on the ceramic mesoporous layer that enable selective polymerization only in this region. The backbone layer lacks these anchoring groups, ensuring polymer grows exclusively in the mesoporous layer where thermal resistance is needed, maintaining precise spatial control over polymer distribution.
Solution Approach 2:
The anchoring groups act as intermediaries between the ceramic mesoporous layer and the polymeric nanofiltration layer. These groups provide specific binding sites that initiate and confine polymerization to the mesoporous layer, preventing unwanted polymer growth in the backbone while ensuring strong interfacial adhesion.
3Strength
If polymerization reaction proceeds from anchoring groups, then polymer growth is enabled, but flux decreases due to pore filling and void space reduction
Solution Approach 1:
The patent controls the polymerization reaction to achieve partial filling of the mesoporous layer rather than complete filling. By limiting the extent of polymerization, sufficient polymer is grown to provide thermal resistance and structural stability, while leaving enough void space maintained to preserve adequate flux for nanofiltration operations.
Solution Approach 2:
The patent optimizes polymerization parameters including monomer concentration, reaction time, and temperature to control the degree of pore filling. By adjusting these parameters, the polymer network is formed with appropriate density to provide mechanical strength and thermal resistance while maintaining sufficient porosity for acceptable flux performance.
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 resulting hybrid membrane exhibits improved thermal and chemical resistance, allowing operation at elevated temperatures with reduced polymer swelling and increased flux, suitable for applications requiring high-temperature stability.
Implementation Method 1
The polymerization reaction is advantageously carried out in presence of a catalyst, allowing to easily stop the polymerization reaction by deactivating the catalyst
Implementation Method 2
Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) process to graft polymers within the mesoporous layer
Implementation Method 3
As the polymer grows inside the pores of the mesoporous layer, the pores (of the ceramic matrix) get filled with polymer and the void space shrinks
Implementation Method 4
The catalyst can be injected at precise locations, e.g., at one side of the support or the first mesoporous layer, from where it can be made to spread out throughout the first layer, e.g., by sustaining a flow through the porous support, or by diffusion due to a concentration gradient
Data Source
AI summary
The present disclosure relates to a nanofiltration membrane and a method of manufacturing a nanofiltration membrane. The method includes providing a support structure having a first mesoporous layer made of TiO2 and/or ZrO2 and a second porous layer adjacent to the mesoporous layer made of aluminum oxide. The method further includes grafting an anchoring group within pores of the first mesoporous layer, wherein the second layer is inert to the grafting step. An initiator for a surface-initiated atom transfer radical polymerization (SI-ATRP) reaction is covalently bonded to the anchoring group. The support structure is impregnated with a monomer and a solvent, and a polymerization reaction is performed, which includes passing a catalyst through the mesoporous layer, the monomer being configured to start the polymerization reaction by grafting from the initiator in the presence of the catalyst.