Mixed Metal Oxide Electrodes for Biofilm Sensor Self-Cleaning
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Solution Overview
Problem
Existing electrochemical biofilm sensors face limitations, including the use of sacrificial anode materials that can reduce sensor lifespan and introduce metal ions into process liquids, as well as the complexity and cost of cleaning electrodes in remote locations.
Innovation Solution
The development of electrochemical biofilm sensors with a first working electrode, a second reference electrode, and a third counter-electrode, where the electrodes are coated with mixed oxides of different noble metals, such as iridium, ruthenium, and platinum, allowing for self-cleaning capabilities and extended sensor lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sacrificial anode materials (e.g., zinc) are used for the counter-electrode, then the sensor can detect biofilm growth through electrochemical reactions, but the sensor lifespan is reduced and metal ions are introduced into the process liquid
Solution Approach 1:
The patent changes the material parameter of the counter-electrode from sacrificial anode materials (zinc) to mixed metal oxide coatings (iridium, ruthenium, platinum on titanium). This material substitution eliminates the harmful dissolution of metal ions while maintaining electrochemical functionality for biofilm detection through oxygen evolution reactions.
Solution Approach 2:
The patent employs composite material structures: mixed metal oxide coatings (combining iridium, ruthenium, and platinum oxides) applied on a titanium substrate. This composite approach provides both structural integrity and catalytic activity for oxygen evolution, replacing sacrificial anodes and eliminating metal ion contamination while extending sensor lifespan.
2Adaptability or versatility
If remote location installation is implemented, then the sensor can monitor biofilm in hard-to-reach systems, but electrode cleaning becomes complex and costly
Solution Approach 1:
The patent implements self-cleaning functionality by applying high current pulses to the mixed metal oxide coated electrodes. These pulses generate strong oxidizing conditions that automatically remove accumulated biofilm from the electrode surfaces, eliminating the need for manual intervention and making the sensor suitable for remote installations where maintenance access is difficult.
3Stability of the object's composition
If mixed oxide coatings of different noble metals are used, then electrode stability and self-cleaning capability are improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies controlled coating parameters including thickness (0.1-50 microns, preferably 2.5 microns ±10%) and composition ratios of different metal oxides. These parameter specifications provide a clear manufacturing target that balances electrode performance (stability and self-cleaning capability) with manufacturability, ensuring reproducible results through defined parameters rather than open-ended material selection.
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 use of mixed metal oxide coatings enhances the stability and longevity of the sensor electrodes, enables self-cleaning of the biofilm, and prevents the introduction of metal ions into the process liquid, thereby improving the sensor's performance and maintenance efficiency.
Implementation Method 1
the kinetics of some evolving reactions on the metal surface of the sensor's working electrode
Implementation Method 2
coated with a coating based on mixed oxides of different noble metals, such as iridium, ruthenium, platinum, rhodium, tantalum or niobium
Implementation Method 3
detect the growth of this bacterial layer by exploiting the alteration, induced by the biofilm, of the kinetics of some evolving reactions on the metal surface
Implementation Method 4
The possibility of 'self-cleaning' for this type of sensor would therefore offer an undoubted advantage
Data Source
Figure 1~2(b)
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AI summary
The invention relates to an electrochemical biofilm sensor comprising a first, a second and a third electrode, wherein the first electrode is a working electrode on whose surface the biofilm whose growth is to be measured develops, the second electrode is a reference electrode having the function of providing a stable reference potential for the polarization of the working electrode, the third electrode is a counter-electrode that can be connected to the first electrode through an electric circuit so as to allow the circulation of current from the first electrode to the third electrode or vice versa, a function of the alteration induced by the biofilm on the kinetics of the evolving reactions on the surface of the first electrode. The first electrode and/or the second electrode and/or the third electrode have the characteristic of being coated with a coating based on mixed oxides of different noble metals, such as iridium, ruthenium, platinum, rhodium, tantalum or niobium, and wherein one or more electrodes are made of titanium or tantalum, and wherein the coating has a thickness of between 0. 1 and 50 microns, preferably 2.5 microns ± 10%.