RO Membrane Biocide Composition for Biofouling Without Dehalogenation
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Solution Overview
Problem
Existing biocides used in reverse osmosis (RO) membranes are ineffective against biofouling, require dehalogenation, are costly, and pose safety risks, leading to increased maintenance costs and operational inconvenience.
Innovation Solution
A biocide composition formed by combining stabilized hypochlorous acid with a water-soluble bromide ion source, such as sodium bromide, is applied to the RO membrane to form hypobromous acid in situ, which effectively controls biofouling without harming the membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional biocides are used to control biofouling, then biofouling control is achieved, but membrane damage occurs and dehalogenation is required
Solution Approach 1:
The patent changes the chemical parameters of the biocide by using bromine instead of chlorine, and by controlling the pH level (6.0-9.0) to optimize the formation of hypobromous acid. This parameter change allows effective biofouling control without the harmful effects of conventional chlorine-based biocides on the membrane.
Solution Approach 2:
The patent converts the potentially harmful bromine into beneficial hypobromous acid through controlled chemical reaction with bromide ions and chlorine at specific pH levels. This transformation allows the system to achieve effective biocidal action while avoiding membrane damage, turning a potentially harmful substance into a beneficial one.
2Reliability
If chlorine-based biocides are used, then biofouling is controlled, but additional dehalogenation steps are required
Solution Approach 1:
The patent extracts and eliminates the need for dehalogenation steps by using bromine-based chemistry that does not require removal of halogen atoms. The bromine is incorporated into the membrane cleaning process directly, simplifying the overall process by removing the complex dehalogenation step entirely.
Solution Approach 2:
The patent introduces bromide ions as an intermediary substance that reacts with chlorine to form hypobromous acid. This intermediary approach allows the system to achieve effective biocidal action without requiring dehalogenation, as the bromide serves as a bridge that transforms the chlorine into a membrane-safe form.
3Reliability
If existing biocides are applied continuously, then biofouling is prevented, but operational costs increase
Solution Approach 1:
The patent implements a self-service system where the membrane cleaning process generates its own biocidal agents. The chlorine and bromide ions react in-situ to form hypobromous acid, eliminating the need for external biocide addition and reducing operational costs while maintaining continuous protection.
Solution Approach 2:
The patent optimizes the concentration parameters of bromide ions (0.01-10% by weight) and pH levels (6.0-9.0) to maximize the efficiency of hypobromous acid formation. By carefully controlling these parameters, the system achieves effective biofouling prevention with minimized substance consumption and reduced operational costs.
4Productivity
If aggressive biocides are used to maintain membrane performance, then flux is maintained, but membrane integrity is compromised
Solution Approach 1:
The patent converts the potentially harmful effect of strong oxidants on membrane integrity into a beneficial process by using controlled hypobromous acid formation at specific pH levels. This transformation allows the system to maintain membrane flux through effective biofouling control while preserving membrane integrity through gentler chemical action.
Solution Approach 2:
The patent changes the chemical parameters by controlling pH levels (6.0-9.0) and bromide ion concentrations to optimize hypobromous acid formation. These parameter changes enable the system to achieve effective biocidal action that protects membrane flux while avoiding the excessive oxidation that would compromise membrane integrity.
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 biocide composition effectively prevents biofouling, reduces maintenance needs, and eliminates the need for dehalogenation, thus lowering costs and improving operational convenience.
Implementation Method 1
A biocide composition formed by combining stabilized hypochlorous acid with a water-soluble bromide ion source, such as sodium bromide, is applied to the RO membrane to form hypobromous acid in situ
Implementation Method 2
the biocide composition effectively prevents biofouling
Data Source
AI summary
The present disclosure relates to biocide compositions, formulations and methods for using formulations. In particular the present disclosure relates to biocide compositions and their use in treating reverse osmosis membranes.