UV-Visible Debromination of Brominated Flame Retardants in Plastics
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Solution Overview
Problem
Current methods for degrading brominated flame retardants in plastic materials either fail to completely remove these toxic substances, lead to the degradation of the plastic itself, or require significant amounts of solvent, making them inefficient and environmentally harmful.
Innovation Solution
A process involving UV-visible irradiation of plastic materials under reduced oxygen pressure, which facilitates the debromination of brominated flame retardants without significantly degrading the plastic, allowing for their removal and enabling the recycling of treated plastics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If UV-visible irradiation is performed in air at atmospheric pressure to debrominate brominated flame retardants, then the flame retardants are degraded, but the plastic material also degrades and cannot be recycled
Solution Approach 1:
The patent applies an inert atmosphere (nitrogen or argon) during UV-visible irradiation to prevent oxygen from participating in the photodegradation process. This selective inert environment allows the degradation of brominated flame retardants while protecting the plastic polymer chains from oxidation and chain scission, thereby maintaining material recyclability.
Solution Approach 2:
The patent changes the atmospheric composition parameter from oxygen-containing (air) to oxygen-free (inert gas), which fundamentally alters the photochemical reaction pathways. This parameter change suppresses harmful photooxidation of the plastic while allowing debromination to proceed through different mechanistic routes.
2Loss of substance
If solvent extraction is used to remove brominated flame retardants from plastic, then the flame retardants are extracted, but large quantities of solvent are required and the halogenated components are not destroyed
Solution Approach 1:
The patent replaces the mechanical/physical separation process (solvent extraction) with a photochemical degradation process. Instead of using solvents to extract and separate flame retardants, UV-visible irradiation directly breaks down the chemical bonds of the brominated compounds, converting them into harmless degradation products that remain in the plastic matrix.
Solution Approach 2:
The patent uses UV-visible radiation as a form of energy that accelerates the breakdown of brominated flame retardants through photolytic oxidation, achieving complete degradation without requiring external solvents or chemicals.
3Object-generated harmful factors
If photodegradation is performed to remove brominated flame retardants, then the flame retardants are debrominated, but the plastic material degrades and loses its recyclability
Solution Approach 1:
The patent uses an inert atmosphere to create a selective chemical environment where only the brominated flame retardants undergo photodegradation while the plastic polymer remains stable. This selective degradation preserves the mechanical and chemical properties needed for recyclability.
Solution Approach 2:
The inert gas atmosphere acts as an intermediary that mediates between the UV-visible radiation and the plastic material, allowing energy transfer to the flame retardants while preventing harmful interactions with the polymer chains.
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
This process effectively removes brominated flame retardants while minimizing damage to the plastic, allowing for the recycling of treated materials and reducing environmental harm.
Implementation Method 1
The present invention relates to a method for the photolytic degradation of brominated flame retardants contained in a plastic material
Implementation Method 2
irradiation with UV-visible radiation under an atmosphere with a reduced oxygen content
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
The invention relates to a method for debrominating at least one brominated flame retardant contained in a plastic material, wherein said plastic material is subjected to irradiation in the UV-visible spectrum. Characteristically, said irradiation is carried out in an atmosphere which, before irradiation, has a pressure equal to or less than 100 Pa and greater than or equal to 0.1 Pa, and in particular equal to 2 Pa, 1.5 Pa, 1 Pa or 0.5 Pa.