Granular Visible Light Catalyst for Persulfate Activation
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Solution Overview
Problem
Existing persulfate advanced oxidation technology struggles to effectively degrade low-concentration organic pollutants and is hindered by the difficulty in recovering iron-based activators, leading to secondary pollution.
Innovation Solution
A visible light catalyst system comprising a conductive carbon material, such as graphene oxide, combined with a transition metal compound like molybdenum disulfide and tungsten oxide, and coated with sodium alginate, which activates persulfate under visible light to synergistically degrade organic pollutants, facilitating easy recovery and broadening the technology's application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If iron-based powdery activator is used to activate persulfate, then degradation-resistant organic pollutants can be oxidized, but the activator is difficult to recover and increases ferric iron content in treated water causing secondary pollution
Solution Approach 1:
The patent changes the physical form of the activator from powder to granular catalyst, and changes the material composition from pure iron-based to composite material (carbon material + transition metal compound + coating material). This parameter change enables both effective persulfate activation and easy recovery through filtration, eliminating secondary pollution while maintaining oxidation capability.
Solution Approach 2:
The patent uses composite granular catalysts consisting of carbon materials (graphene, carbon nanotubes), transition metal compounds (oxides, sulfides), and coating materials. This composite structure combines the advantages of different materials: carbon provides conductivity and stability, transition metals provide catalytic activity for persulfate activation, and coating materials facilitate recovery. The composite structure resolves the contradiction between effective oxidation and easy recovery without secondary pollution.
2Reliability
If persulfate advanced oxidation technology is used for high-concentration organic wastewater, then strong oxidizing ability is achieved, but it cannot satisfy the requirement for low-concentration organic wastewater treatment
Solution Approach 1:
The patent introduces granular catalysts with controlled surface area, pore structure, and catalytic activity that can be optimized for different wastewater concentrations. The catalysts enable persulfate activation at lower concentrations through enhanced surface catalysis, expanding the applicable concentration range from only high-concentration to both high and low-concentration organic wastewater while maintaining strong oxidizing ability.
3Productivity
If traditional iron-based activator is used, then persulfate can be activated to degrade organic pollutants, but the activator cannot be easily recovered after reaction
Solution Approach 1:
The patent segments the activator into discrete granular particles with specific size ranges (0.5-5mm) rather than using fine powders. This segmentation allows easy separation from treated water through filtration or sedimentation, dramatically improving recovery ease while maintaining high degradation efficiency through the internal catalytic structure of the granules.
Solution Approach 2:
The patent changes the physical parameters of the activator from powder form to granular form with controlled size, density, and surface properties. These parameter changes enable the activator to maintain high catalytic activity for persulfate activation while being easily recoverable through physical separation methods, resolving the contradiction between degradation efficiency and recovery ease.
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 visible light catalyst system achieves high degradation efficiency for low-concentration organic pollutants, with a degradation rate of up to 96.5%, reducing secondary pollution and enhancing the applicability of persulfate advanced oxidation technology.
Implementation Method 1
Photocatalysis technology is to degrade organic pollutants by the energy of sunlight, and is recognized as a green water treatment technology. Photocatalyst can generate photo-induced electrons under the condition of light, which is likely to activate persulfate.
Implementation Method 2
Photocatalyst can generate photo-induced electrons under the condition of light, which is likely to activate persulfate.
Implementation Method 3
Under the excitation by activator, persulfate produces highly reactive sulfate radicals to oxidize degradation-resistant organic matter.
Implementation Method 4
persulfate produces highly reactive sulfate radicals to oxidize degradation-resistant organic matter
Data Source
AI summary
A visible light catalyst, its preparation method, a visible light catalyst activated persulfate system and its use. The visible light catalyst includes a carbon material, a transition metal compound and a coating material. The carbon material is conductive carbon material, and the transition metal compound is selected from one or more of transition metal oxides, transition metal sulfides, and acid or salt compounds containing a transition metal. The visible light catalyst has high visible light photocatalytic activity and performance of degrading organic pollutants and activating persulfate which can result in synergistically degrading degradation-resistant organic pollutants.