Microplastic Enrichment via Marked Screen Meshes and Micro-Spray
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Solution Overview
Problem
Current methods for extracting and analyzing microplastics from secondary effluent in wastewater treatment plants are inefficient and cause significant loss and damage to samples due to the use of high-concentration chemicals and multiple transfer steps, leading to inaccurate analysis.
Innovation Solution
An integrated device and method for enrichment, purification, and separation of microplastics using a multi-stage filtering system with marked screen meshes and a micro-spray system, where microplastics are enriched on the surface of screen meshes and subjected to in-situ purification and separation using low-concentration chemicals and heat treatment, minimizing sample transfer and chemical exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional purification methods using high-concentration acids, bases or oxidants are adopted, then organic foulants are degraded and removed, but the molecular structure of microplastics is damaged and sample loss increases
Solution Approach 1:
The patent changes the concentration parameter of chemical reagents from high-concentration (tens of moles in conventional methods) to low-concentration (0.1-1.0 mol/L), and extends the treatment time from minutes to days. This parameter transformation allows organic foulants to be degraded while preserving microplastic structural integrity, resolving the contradiction between purification effectiveness and sample preservation.
Solution Approach 2:
The patent implements a multi-stage periodic treatment process where samples undergo repeated cycles of chemical treatment and rinsing over extended periods (2-7 days). This periodic action allows gradual degradation of organic foulants while minimizing damage to microplastics, compared to the single-step harsh treatment in conventional methods.
2Reliability
If multiple transfer steps are used in conventional extraction methods, then enrichment, purification and separation are achieved, but operation complexity increases and sample loss increases
Solution Approach 1:
The patent merges the enrichment, purification and separation steps into a single integrated filtration device. The filtration unit combines screening (enrichment), chemical treatment (purification), and density separation (separation) functions in one system, eliminating the need for multiple separate operations and transfers between different equipment, thus reducing both complexity and sample loss.
Solution Approach 2:
The filtration device performs multiple functions simultaneously: it acts as a screen for enrichment, a reaction vessel for purification, and a separation chamber for density-based classification. This multi-functionality replaces the conventional sequence of separate operations, simplifying the overall process while maintaining separation effectiveness.
3Quantity of substance
If high-concentration chemicals are used for purification, then organic foulant degradation is achieved, but microplastic structural properties are damaged
Solution Approach 1:
The patent transforms the chemical concentration parameter from high (tens of moles) to low (0.1-1.0 mol/L), and compensates by extending treatment duration from minutes to days. This parameter swap achieves complete organic foulant removal while preserving microplastic structural properties, directly resolving the contradiction between foulant degradation and structural integrity.
4Manufacturing precision
If conventional density separation using saturated salt solutions is used, then low-density microplastics are separated, but high-density microplastics are lost
Solution Approach 1:
The patent changes the density parameter of the separation medium from saturated salt solutions (limited density range) to bromoform (density 2.89 g/cm³), which matches the density of high-density microplastics like PVC and PET. This parameter change enables effective separation of both low-density and high-density microplastics, resolving the contradiction between separation accuracy and material loss.
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 method effectively prevents sample loss and damage, achieving high separation accuracy (not less than 90%) while maintaining the integrity of microplastic properties for accurate analysis, and is suitable for various water bodies including surface water, lake water, and groundwater.
Implementation Method 1
porous media such as trawl nets, plankton nets, screen meshes, etc. are adopted to separate the microplastics from water bodies through physical interception
Implementation Method 2
leaving the filtering system standing in a constant temperature environment to remove residual moisture from surfaces of the microplastics
Implementation Method 3
The currently adopted purification methods involve acid degradation, alkaline degradation, and oxidation degradation. Mainly, by introducing strong acids, strong bases or oxidants, the molecular structure of the organic foulant is destroyed to be degraded and removed
Implementation Method 4
By using the density difference between microplastics and other foulants, it is possible for the foulant particles to sink to the bottom, and the microplastics with lower density are suspended on the surface of the solution
Implementation Method 5
the foulant particles to sink to the bottom, and the microplastics with lower density are suspended on the surface of the solution
Data Source
AI summary
An integrated device and method for enrichment, purification and separation of microplastics in a secondary effluent are provided. This integrated device comprises a micro-spray system and a filtering system with multi-stage filtering units, and marked screen meshes were installed in each filtering unit. The microplastics in secondary effluent are enriched on the surface of the marked screen meshes through the retaining effect. Then, lower concentration of alkali, acid or oxidant combined with the heat treatment to weaken the interaction forces between the inorganic/organic foulants and the enriched microplastic. On this basis, the micro-spray system was used to rinse the multistage filtration system, which generated shear force to carry away the foulants on the surfaces of the enriched microplastics, thereby achieving the purification and separation of microplastics synchronously. These are performed in the marked screen meshes, in which the microplastic are not subject to any path transfer or loss.