Organometallic framework
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Solution Overview
Problem
Metal-organic frameworks (MOFs) struggle to effectively adsorb water vapor at low relative humidity and maintain a small humidity difference between adsorption and desorption, leading to insufficient heat output in chemical heat pumps and humidity control systems.
Innovation Solution
A metal-organic framework comprising an aluminum ion, a first ligand with a heterocycle having two carboxyl groups, a second ligand with a different heterocycle, and an optional third ligand, where the first ligand is present in 0-70 mol%, the second ligand in 0-90 mol%, and the third ligand in 0-80 mol%, optimizing the balance of hydrophilic and hydrophobic regions for improved water vapor adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional MOFs are used as desiccants, then water vapor adsorption occurs, but the adsorption requires high relative humidity and the humidity difference between adsorption and desorption is large
Solution Approach 1:
The patent applies local quality by creating MOFs with heterogeneous ligand distributions where hydrophilic ligands (containing O, N, F atoms) and hydrophobic ligands are spatially separated and distributed in specific ratios. This local differentiation of hydrophilic/hydrophobic regions within the MOF structure enables selective water vapor adsorption at low humidity while maintaining manageable desorption characteristics
Solution Approach 2:
The patent employs composite materials by combining multiple types of organic ligands with different hydrophilicities within a single MOF structure. The composite ligand system (comprising ligands with heteroatoms like O, N, F and ligands without such atoms) creates a material with balanced adsorption-desorption properties that conventional homogeneous MOFs cannot achieve
2Quantity of substance
If conventional MOFs are used as desiccants, then water vapor adsorption occurs, but the heat output is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional ratios of different ligand types (hydrophilic vs hydrophobic) in the MOF structure. By adjusting the proportion of ligands containing heteroatoms (O, N, F) versus those without, the patent optimizes both the adsorption capacity and the heat output parameters simultaneously, achieving a balance that conventional MOFs cannot reach
3Quantity of substance
If conventional MOFs are used as desiccants, then water vapor adsorption occurs, but the moisture removal performance is insufficient
Solution Approach 1:
The patent creates local quality variations within the MOF structure by distributing hydrophilic ligands (with O, N, F atoms) and hydrophobic ligands in specific spatial arrangements and ratios. This local heterogeneity enables the MOF to effectively capture water vapor molecules at low humidity levels while maintaining efficient moisture removal rates, addressing both adsorption quantity and productivity requirements
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 MOF achieves water vapor adsorption at low relative humidity with a reduced humidity difference between adsorption and desorption, enhancing the performance of chemical heat pumps and humidity control systems.
Implementation Method 1
MOFs can adsorb water vapor, and therefore are considered for use as desiccants in chemical heat pumps and humidity control systems
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
The present invention provides a metal-organic framework which can both adsorb water vapor in low relative humidity and reduce the magnitude of the humidity difference between the adsorption humidity and the desorption humidity. A metal organic framework wherein the metal ion is an aluminum ion, a first ligand is an organic compound ion consisting of a first heterocycle having two carboxyl groups, and a heteroatom composing the first heterocycle is present on the minor angle side of the angle created by the two carboxyl groups, a second ligand is different than the first ligand, is an organic compound ion consisting of a second heterocycle having two carboxyl groups, and a heteroatom composing the second heterocycle is present on the major angle side of the angle create by the two carboxyl groups, and a third ligand is different than the first ligand and the second ligand, is an organic compound ion having two carboxyl groups, and the first ligand, second ligand, and third ligand are present in a specific ratio.