Fractionation Tool for Dioxins Using Segmented Adsorption Layers
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Solution Overview
Problem
Current methods for fractionating dioxins in solutions are unable to accurately separate non-ortho PCBs, PCDDs, and PCDFs from mono-ortho PCBs, leading to unreliable analytical results due to mixing of dioxin types in the same solution.
Innovation Solution
A tool with a tubular body containing a purification layer of silver nitrate and sulfuric acid silica gel, followed by an adsorption layer of activated carbon-containing silica gel and graphite-containing silica gel, and an optional alumina layer, is used to fractionate dioxins by injecting the solution and solvent through the layers, allowing non-ortho PCBs, PCDDs, and PCDFs to be adsorbed in one layer and mono-ortho PCBs in another, with optional separation using a second alumina layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single adsorption layer is used to fractionate dioxins, then the device complexity is reduced, but the measurement precision of dioxin separation is insufficient
Solution Approach 1:
The adsorption layer is segmented into multiple functional layers with different adsorption characteristics. The first adsorption layer (activated carbon-containing silica gel) selectively adsorbs PCDDs and PCDFs, while the second adsorption layer (graphite-containing silica gel) selectively adsorbs non-ortho PCBs. This segmentation enables precise separation of different dioxin groups without requiring a single complex adsorption material.
Solution Approach 2:
The patent employs composite adsorption materials combining different carbon-based substances with silica gel supports. The first layer uses activated carbon-containing silica gel, and the second layer uses graphite-containing silica gel. These composite materials provide complementary adsorption properties that enable selective fractionation of different dioxin types, achieving high separation precision through material composition rather than structural complexity.
2Measurement precision
If multiple adsorption layers are used to improve dioxin separation, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
Each adsorption layer is designed with local quality tailored to specific dioxin groups. The first adsorption layer has activated carbon-containing silica gel optimized for PCDDs and PCDFs, while the second layer has graphite-containing silica gel optimized for non-ortho PCBs. This local optimization of adsorption properties in different layers achieves high separation precision without requiring uniform complexity throughout the entire device.
Solution Approach 2:
The patent utilizes porous silica gel as a support matrix for both adsorption layers, providing high surface area and controlled pore structures. The porous materials enable efficient mass transfer and selective adsorption based on molecular size and polarity differences, achieving precise separation with relatively simple layer structures rather than complex configurations.
3Ease of operation
If dioxins are not fractionated, then the analysis process is simplified, but the reliability of quantitative analysis decreases due to interference
Solution Approach 1:
The patent extracts and separates different dioxin groups (PCDDs, PCDFs, and non-ortho PCBs) from the mixed extract into distinct fractions using sequential adsorption layers. By taking out each dioxin group into separate eluates, the method eliminates mutual interference in quantitative analysis, improving reliability while maintaining operational simplicity through automated sequential elution.
Solution Approach 2:
The patent introduces different solvents as intermediaries to selectively elute different dioxin groups. A first solvent elutes PCDDs and PCDFs from the first adsorption layer, while a second solvent elutes non-ortho PCBs from the second adsorption layer. These intermediary solvents enable clean separation and prevent cross-contamination between fractions, ensuring reliable quantitative analysis without complex manual separation procedures.
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 approach enables high-accuracy fractionation of dioxins into distinct groups, reducing interference and improving the reliability of quantitative analysis by separating dioxins effectively, as demonstrated by high recovery rates and minimal interference peaks in HRGC/HRMS analysis.
Implementation Method 1
the primary column is supplied with a hydrocarbon solvent. The hydrocarbon solvent dissolves dioxins in the injected extract, and passes through the primary column and the secondary column. During the passage, dioxins dissolved in the hydrocarbon solvent pass through the purifying agent of the primary column, and are adsorbed to the adsorbing agent of the secondary column. On the other hand, impurities contained in the extract are dissolved in the hydrocarbon solvent together with dioxins, and partially degraded while they are passing through the purifying agent of the primary column, and partially adsorbed.
Implementation Method 2
impurities contained in the extract are dissolved in the hydrocarbon solvent together with dioxins, and partially degraded while they are passing through the purifying agent of the primary column, and partially adsorbed
Implementation Method 3
all kinds of dioxins contained in the extract are adsorbed to the adsorbing agent in the secondary column, and the adsorbed dioxins are extracted with alkylbenzene
Implementation Method 4
the adsorption layer is separated into a first adsorption layer including the activated carbon-containing silica gel layer and the graphite-containing silica gel layer, and a second adsorption layer including the alumina layer
Implementation Method 5
The hydrocarbon solvent dissolves dioxins in the injected extract, and passes through the primary column and the secondary column
Implementation Method 6
the secondary column is supplied with an alkylbenzene capable of dissolving dioxins. By collecting the alkylbenzene passing through the secondary column, it is possible to obtain an impurities-free alkylbenzene solution of dioxins
Data Source
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AI summary
A fractionating tool (200) capable of fractionating dioxins contained in a solution of dioxins includes a tubular body (210) opening at both ends, and a purification layer (220) and an adsorption layer (230) packed therein. The adsorption layer (230) includes a first adsorption layer (240) including an activated carbon-containing silica gel layer (241) and a graphite-containing silica gel layer (242), and a second adsorption layer (250) including an alumina layer (251). When a solution of dioxins is injected into the purification layer (220) and then a solvent capable of dissolving dioxins is supplied thereto, the solvent dissolves dioxins and passes through the purification layer (220) and the adsorption layer (230). In this process, non-ortho PCBs, PCDDs and PCDFs among dioxins are adsorbed to the first adsorption layer (240), and mono-ortho PCBs among dioxins are adsorbed to the second adsorption layer (250). As a result, dioxins are fractionated.