PVC Filter Chromium Removal via Hydrogen Peroxide Oxidation
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Solution Overview
Problem
Existing methods for removing residual chromium from polyvinyl chloride (PVC) membranes and films are destructive due to the need for alkaline modifications, which damage the filters and interfere with analytical results by not distinguishing between environmentally harvested chromium and manufacturing byproducts.
Innovation Solution
A non-destructive process using a non-alkaline solution of concentrated hydrogen peroxide at elevated temperatures to convert and remove chromium, specifically hexavalent chromium, from PVC filters without altering the filter's structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alkaline modification is used to remove chromium from PVC filters, then chromium removal efficiency is improved, but the filter structure is damaged
Solution Approach 1:
The invention changes the chemical parameters of the treatment solution from alkaline to non-alkaline (pH 4.5-5.0), and changes the temperature parameter to elevated temperatures (30-80°C). This parameter transformation allows chromium removal while preserving the PVC filter structure, resolving the contradiction between removal efficiency and structural integrity
Solution Approach 2:
The invention replaces the chemical mechanism (alkaline modification) with a different chemical mechanism (non-alkaline oxidation using hydrogen peroxide at elevated temperatures). This substitution eliminates the structural damage caused by alkaline conditions while maintaining effective chromium removal capability
2Quantity of substance
If conventional chromium removal methods are used, then chromium is removed from filters, but the filters become unsuitable for analytical use
Solution Approach 1:
By changing the pH parameter from alkaline to non-alkaline (pH 4.5-5.0) and introducing temperature control (30-80°C), the invention achieves chromium removal that preserves filter integrity, maintaining reliability for analytical use while reducing chromium content
Solution Approach 2:
The invention converts the potential harm of chromium presence into a benefit by using controlled non-alkaline oxidation conditions that selectively remove chromium while preserving the filter's analytical utility, turning a problematic situation into a solution that maintains both low chromium content and filter reliability
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 over 90% of chromium from PVC filters in a single treatment, maintaining the filter's structural integrity and enabling accurate monitoring of workplace chromium levels without interference from manufacturing byproducts.
Implementation Method 1
Cr (III) can be oxidized to Cr (VI) with hydrogen peroxide under alkaline conditions
Implementation Method 2
The concentrated hydrogen peroxide solution is heated to a temperature from about 30 deg C. to not greater than 80 deg C.
Data Source
AI summary
A non-destructive process for removing chromium from polyvinyl chloride filters is disclosed. The process involves immersing the polyvinyl chloride filters in a concentrated hydrogen peroxide solution at elevated temperatures, followed by rinsing with deionized water. Removing the background concentration of chromium from the filters allows for more accurate measurements of the amount of hexavalent and total chromium present in workplace environments.