Open-Cell Foam Contaminant Sampling
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Solution Overview
Problem
Traditional methods for testing water and air for contaminants, such as grab sampling, are inadequate for detecting transient and low-concentration contaminants and fail to accurately represent exposure over time, especially in non-equilibrium water systems, and existing semi-permeable membrane devices are costly and ineffective for high molecular weight contaminants.
Innovation Solution
An open-cell foam matrix material, preferably composed of a copolymer of ethylene and alkyl acrylate, is used to accumulate contaminants over time, maximizing surface area for absorption and adsorption of oils and chemicals while repelling water, allowing for more accurate and cost-effective detection of a wide range of contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If semi-permeable membrane (SPMD) non open-cell foam sampling is used, then the ability to concentrate contaminants over extended time period is improved, but the cost increases and absorption of high molecular weight contaminants is reduced or eliminated
Solution Approach 1:
The patent employs open-cell foam materials with controlled porosity to enable contaminant absorption. The open-cell structure allows contaminants to penetrate and accumulate within the foam matrix, providing effective sampling while using cost-effective materials rather than expensive semi-permeable membranes.
Solution Approach 2:
The patent utilizes composite foam materials comprising multiple polymers (e.g., polyethylene, polypropylene, polystyrene) with specific properties. These composite materials are engineered to balance absorption capacity for high molecular weight contaminants, structural integrity, and cost-effectiveness, resolving the contradiction between detection precision and manufacturing cost.
2Ease of operation
If grab sampling is used, then the sampling process is simple and instantaneous, but the ability to detect transient and low-concentration contaminants is lost
Solution Approach 1:
The foam sampling devices are deployed in advance and left in the water environment for extended periods (days to weeks) to pre-accumulate contaminants. This preliminary action allows transient and low-concentration contaminants to build up to detectable levels before the device is retrieved for analysis, maintaining simplicity while improving detection capability.
Solution Approach 2:
The foam devices continuously accumulate contaminants over the deployment period, providing ongoing sampling action rather than a single instantaneous measurement. This continuous accumulation process ensures that transient contaminants are captured and concentrated, improving detection precision while keeping the operation simple.
3Loss of time
If grab sampling is used, then the sampling reflects instantaneous conditions, but it fails to represent exposure over time in non-equilibrium water systems
Solution Approach 1:
The foam sampling devices are deployed for extended periods (excessive time compared to instantaneous sampling) to capture contaminant accumulation over time. This excessive exposure time ensures that the sampling represents average exposure conditions rather than transient instantaneous values, providing better information about actual exposure while accepting longer deployment time.
4Duration of action of moving object
If SPMD devices are used for monitoring, then the sampling extends over time, but the detection of high molecular weight contaminants becomes difficult and cost prohibitive
Solution Approach 1:
The open-cell foam structure provides larger pore sizes and higher porosity compared to semi-permeable membranes, enabling effective absorption and accumulation of high molecular weight contaminants. The porous structure allows these larger molecules to penetrate and reside within the foam matrix, making them detectable after extended sampling periods.
Solution Approach 2:
The patent changes key material parameters including foam porosity, cell size, and polymer composition to optimize absorption of high molecular weight contaminants. By adjusting these parameters, the device maintains effective sampling duration while improving detection capability for larger molecules that are difficult to detect with traditional SPMD devices.
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 open-cell foam matrix provides a more accurate representation of contaminant exposure over time, reducing variability and detecting contaminants that may be undetectable with traditional methods, including high molecular weight substances, and can be used in various water bodies and environments.
Implementation Method 1
The open-cell structure behaves as the alveoli of the human lungs in that it maximizes surface area which maximizes the efficacy of the open-cell foam's ability to attract oil, chemicals, and related contamination at the molecular level
Implementation Method 2
The open-cell structure behaves as the alveoli of the human lungs in that it maximizes surface area which maximizes the efficacy of the open-cell foam's ability to attract oil, chemicals, and related contamination at the molecular level, while repelling water
Data Source
AI summary
A method of removing and detecting the presence of substances from at least one of a body of water (20) and the air. The method includes placing into the body of water (20) or into the air an open-cell foam material (12, 14, 16), removing separate portions of the open-cell foam material (12, 14, 16) from the water (20) or air at different exposure times after the open-cell foam material (12, 14, 16) was placed into the water (20) or air, and determining the presence in the removed separate portions of one or more substances that were removed from the water (20) or air by the open-cell foam material (12, 14, 16).