RO Membrane Rejection Rate Stabilization via Polyphenol-Surfactant Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for improving the rejection rate of reverse osmosis (RO) membranes often result in decreased permeation flux and stability, especially when treated with polyphenols, as they can peel away from the membrane surface and enhance contaminant adherence due to increased charging properties.
Innovation Solution
A method involving the use of an aqueous solution containing polyphenol, modified poly(vinyl alcohol), high molecular polysaccharides, and poly(amino acids) to pass through the RO membrane, which stabilizes the polyphenol adsorption and reduces membrane charging, thereby enhancing rejection rate and flux stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyphenol is used to improve rejection rate, then rejection rate is restored, but permeation flux decreases by 20% or more
Solution Approach 1:
The invention uses a composite treatment solution containing polyphenol (50-500 mg/L), surfactant (0.1-10 mg/L), and alkaline substance (pH 8-12) to treat the RO membrane. This composite approach allows the polyphenol to restore rejection rate while the surfactant and alkaline substance prevent excessive flux decline by controlling the treatment conditions and preventing membrane pore blockage
Solution Approach 2:
The invention specifies precise parameter ranges: polyphenol concentration (50-500 mg/L), surfactant concentration (0.1-10 mg/L), and pH (8-12). By optimizing these parameters, the treatment restores rejection rate while minimizing flux decline to less than 10%, resolving the contradiction between rejection rate improvement and flux maintenance
2Reliability
If polyphenol is adhered to membrane surface, then rejection rate is improved, but polyphenol peels away and contaminant adherence increases
Solution Approach 1:
The invention introduces surfactant as an intermediary substance that mediates between polyphenol and membrane surface. The surfactant (0.1-10 mg/L) forms a stable complex with polyphenol, preventing polyphenol from peeling away while also preventing excessive contaminant adherence by controlling surface charging properties
Solution Approach 2:
The invention controls pH (8-12) to optimize polyphenol adsorption stability on the membrane surface. At this pH range, polyphenol maintains stable adsorption without excessive charging that would cause contaminant accumulation, and the alkaline environment prevents polyphenol degradation
3Reliability
If membrane charging property is enhanced, then rejection rate is improved, but contaminant adherence increases
Solution Approach 1:
The surfactant acts as an intermediary that modulates membrane surface charging. It provides sufficient negative charge for salt rejection while preventing excessive charging that would attract and retain cationic contaminants, thus resolving the contradiction between rejection performance and contaminant resistance
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 method efficiently restores the rejection rate of RO membranes with improved stability and contamination resistance, maintaining a high permeation flux and preventing membrane degradation.
Implementation Method 1
Method for improving rejection rate of reverse osmosis membrane
Implementation Method 2
a method in which the rejection rate is improved by adhering an anionic or a cationic high molecular compound to a membrane surface
Data Source
AI summary
To provide a method for improving a rejection rate of an RO membrane, which further improves the stability of removal performance (rejection rate) and flux stability (sustainability of contamination resistance). In a method for improving a rejection rate of an RO membrane, including a step of allowing an aqueous solution containing a polyphenol to pass through an RO membrane, the method further includes a step of allowing an aqueous solution containing at least one type selected from the group consisting of a modified poly(vinyl alcohol), a high molecular polysaccharide, and a poly(amino acid) to pass through the RO membrane. The method preferably further includes a step of allowing an aqueous solution containing an organic compound having an amino group and having a molecular weight of 1,000 or less to pass through the RO membrane.