Recyclable Electret Filtering Membrane via Friction Electrification
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Solution Overview
Problem
Existing air filtration technologies using electret filtering materials face challenges with increasing filtration resistance, energy consumption, and secondary air pollution due to particle deposition, as well as complications in effective dust removal and charge regeneration, particularly with high-voltage corona recharging methods that can produce ozone.
Innovation Solution
A recyclable electret filtering membrane with a surface containing C—F bonds is developed through electrostatic spinning, followed by calcining and corona charging, and a water drop rolling cleaning and friction electrification method for dust removal and charge regeneration, which reduces filtration resistance and energy consumption while avoiding ozone production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-voltage corona recharging is used to regenerate electret filtering material, then charge regeneration is achieved, but operation becomes complicated and ozone may be produced
Solution Approach 1:
The patent changes the charging method from high-voltage corona discharge to low-voltage friction electrification. By modifying the electrical parameters (voltage level, charging mechanism), the system achieves charge regeneration without the complications and harmful effects of high-voltage corona discharge, thus resolving the contradiction between reliability and device complexity
Solution Approach 2:
The patent replaces the electrical field-based corona charging mechanism with a mechanical friction-based electrification system. Water drops physically contact the filter surface, and through friction, transfer charges. This mechanical substitution eliminates the need for complex high-voltage power supplies and corona discharge control systems
2Reliability
If high-voltage corona recharging is used to regenerate electret filtering material, then charge regeneration is achieved, but ozone production occurs
Solution Approach 1:
The patent replaces the electrical field-based corona charging mechanism with a mechanical friction-based electrification system. Water drops physically contact the filter surface, and through friction, transfer charges. This mechanical substitution eliminates the need for complex high-voltage power supplies and corona discharge control systems
3Loss of substance
If gas flushing is used to remove deposited particles, then dust removal is attempted, but effective particle removal is difficult to achieve
Solution Approach 1:
The patent introduces water drops as an intermediary substance to facilitate particle removal. Instead of using gas flushing that fails to effectively remove particles, water drops contact the filter surface, enable particle detachment through wetting and rolling actions, and carry particles away, thus significantly improving dust removal efficiency
Solution Approach 2:
The patent transitions from gas-based flushing to liquid-based particle removal. By using water drops (hydraulic approach) instead of gas flow, the system achieves effective particle detachment and removal from the filter surface, resolving the inadequacy of gas flushing
4Reliability
If electret filtering material is used to improve filtering efficiency, then electrostatic trapping effect is achieved, but filtration resistance increases with particle deposition
Solution Approach 1:
The patent implements a regeneration system that periodically removes accumulated particles from the electret filter surface using water drops. By discarding the deposited particles that cause resistance increase and recovering the filter's electrostatic properties through friction electrification, the system maintains both high filtering efficiency and low filtration resistance over extended operation periods
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 solution achieves a high dust removal rate of 90%-100% and charge recovery rate of 90%-125%, maintaining PM2.5 filtering efficiency at 94% or greater, with improved recyclability and reduced operational complexity.
Implementation Method 1
water drops undergo friction electrification with the surface of the filtering membrane during rolling
Implementation Method 2
performing electrostatic spinning for the spinning solution to obtain a fiber membrane
Implementation Method 3
subsequently performing corona charging for the porous fiber membrane to obtain the recyclable electret filtering membrane
Data Source
AI summary
Provided are a recyclable electret filtering membrane, a preparation method therefor and a cleaning and charge regeneration method therefor. The preparation method includes: dissolving fluorine-containing polymer particles and polyoxyethylene particles in deionized water to prepare a spinning solution, and then performing electrostatic spinning, calcining, cooling, drying and corona charging to obtain the recyclable electret filtering membrane. A surface of the filtering membrane is subjected to water drop rolling cleaning and friction electrification after dust holding, and then dried to realize charge regeneration and reuse. The filtering membrane obtained in the present invention has an initial surface potential of (−600)-(−950) V, the potential can be regenerated to (−700)-(−1000) V by water drop rolling and electrification after dust holding, the charge recovery rate is 90%-125%, the dust removal rate is 90%-100%, and the filtering efficiency for PM2.5 is equal to or greater than 94%.