Dynamic-Pore Co-DPB MOF for Humidity-Stable SF6/N2 Separation
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Solution Overview
Problem
Existing adsorption separation technologies for sulfur hexafluoride (SF6) face challenges in achieving high-purity separation from nitrogen (N2) with low energy consumption, while maintaining stability and efficiency, especially under humid conditions, due to limitations in precise pore size control and moisture resistance of conventional porous materials.
Innovation Solution
A pyrazole cobalt-based metal-organic framework (Co-DPB) with a dynamic pore size, constructed using a bidentate pyrazole ligand, allows for efficient SF6 capture and selective separation of SF6/N2, utilizing a flexible benzene ring structure to accommodate and bind SF6 molecules, achieving high adsorption capacity and selectivity, even under humid conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional porous materials (zeolite, porous carbon) are used for SF6 adsorption, then initial progress in SF6 capture is achieved, but precise control of pore size and pore environment is limited, resulting in insufficient separation performance
Solution Approach 1:
The patent employs MOF materials where pore size and pore environment can be precisely tuned by changing the metal ion/cluster and organic ligand parameters. The Co-DPB material achieves a pore size of 4-8 Å through specific coordination between Co2+ ions and pyrazole ligands, enabling precise molecular recognition and separation of SF6 from N2
Solution Approach 2:
The patent creates composite MOF structures by combining metal ions (Co2+) with organic ligands (pyrazole-based compounds) to form a coordinated polymer network. This composite approach allows simultaneous optimization of pore size, pore environment, and chemical functionality for enhanced SF6 capture performance
2Reliability
If MOF materials are used to achieve ultra-high SF6/N2 selectivity, then separation performance is improved, but moisture causes MOFs to degrade after multiple cycles
Solution Approach 1:
The patent introduces hydrophobic modifications at specific locations within the MOF structure. The Co-DPB material incorporates hydrophobic pore environments through specific ligand design, creating localized water-resistant zones that protect the MOF framework from moisture-induced degradation while maintaining high SF6 selectivity
Solution Approach 2:
The patent pre-protects the MOF structure against moisture damage by incorporating hydrophobic components during synthesis. The Co-DPB material is designed with inherent water resistance through its ligand framework, providing beforehand cushioning against humidity that would otherwise cause degradation during cyclic operation
3Reliability
If cryogenic distillation or liquefaction is used for SF6/N2 separation, then separation can be achieved, but energy consumption is high and purification efficiency is low for low-concentration SF6
Solution Approach 1:
The patent replaces energy-intensive mechanical separation processes (cryogenic distillation, liquefaction) with adsorption-based separation using Co-DPB MOF. The material's selective pore structure enables SF6 capture at room temperature through molecular recognition, eliminating the need for cryogenic conditions and significantly reducing energy consumption
Solution Approach 2:
The patent utilizes the porous structure of MOF materials to achieve separation based on molecular size and shape recognition. The Co-DPB material's 4-8 Å pores selectively adsorb SF6 molecules while excluding N2, providing high purification efficiency for low-concentration SF6 streams without requiring phase changes or high energy input
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 Co-DPB material achieves high SF6 adsorption capacity (2.82 mmol/g) and selectivity (2485) at room temperature and low pressure, maintaining high-purity SF6 recovery (>99.9%) and structural integrity through multiple cycles, even at high humidity, surpassing previous materials in efficiency and stability.
Implementation Method 1
a core of the adsorption separation technology lies in research and development of adsorbents
Implementation Method 2
MOFs show unique advantages in selective molecular recognition and separation
Implementation Method 3
Due to a vibrational flexibility of a benzene ring structure of the bidentate pyrazole ligand H2DPB, the Co-DPB presents a molecular trap structure with a dynamic size (4-8 Å)
Data Source
AI summary
The present disclosure provides a pyrazole cobalt-based metal-organic framework material, a chemical formula of the pyrazole cobalt-based metal-organic framework material is CoC12H8N4, and the pyrazole cobalt-based metal-organic framework material is named Co-DPB; a ligand of the Co-DPB is 1,3-Di (1-H-pyrazolyl) benzene H2DPB, and a structural formula isand the Co-DPB is prepared by a solvothermal reaction of an organic ligand H2DPB and a cobalt source; and the Co-DPB is a purple bulk crystal material.