Rotating-Disc Seawater Electrolysis for Brucite Production

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Solution Overview

Problem

There is a need for efficient methods to produce brucite (Mg(OH)2) from seawater to increase ocean alkalinity and enhance carbon storage capacity, as well as methods to increase the pH of ocean water for carbon capture.

Innovation Solution

An electrochemical process using a rotating disc cathode and a membrane-less reactor to electrolytically generate hydroxide ions from seawater, precipitating brucite (Mg(OH)2) solids, which increases ocean alkalinity and promotes atmospheric carbon dioxide dissolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional brucite production methods (calcining magnesium carbonate or precipitation from seawater) are used, then brucite can be obtained, but the process requires high energy input and complex operational procedures

Engineering Contradiction:

Improvebrucite production efficiencyVSAvoidenergy requirement

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent replaces thermal processing (calcining at high temperatures) and chemical precipitation methods with an electrochemical method using a rotating disc cathode reactor. The electrochemical reduction of magnesium ions directly produces brucite precipitates at the cathode surface, eliminating the need for high-temperature calcination and complex chemical reagent addition, thereby significantly reducing energy consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental reaction parameter from thermal energy input to electrical energy input. By applying a controlled electric current density to the rotating disc cathode, the system achieves brucite formation through electrochemical reduction rather than thermal decomposition or chemical precipitation, optimizing energy efficiency.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If alkaline materials are added to increase ocean pH for carbon storage, then carbon storage capacity is enhanced, but the process requires additional material input and operational complexity

Engineering Contradiction:

Improvecarbon storage capacityVSAvoidprocess complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The rotating disc cathode system generates hydroxide ions in situ through electrochemical reduction of water at the cathode surface. These hydroxide ions immediately react with dissolved magnesium ions in seawater to form brucite precipitates directly on the cathode. This self-contained process eliminates the need for external alkaline material addition and complex dosing systems.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent combines multiple functions into a single electrochemical process: (1) generation of hydroxide ions for pH increase, (2) precipitation of brucite for carbon storage enhancement, and (3) simultaneous production of hydrogen gas as a valuable byproduct. This integration simplifies the overall system compared to separate alkaline addition and brucite production processes.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If brucite is produced by traditional precipitation from seawater, then Mg(OH)2 can be obtained, but the process lacks efficiency and scalability

Engineering Contradiction:

Improvebrucite production rateVSAvoidmanufacturing simplicity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The rotating disc cathode introduces dynamic motion to the electrochemical process. The rotation creates continuous renewal of the cathode surface, enhances mass transport of magnesium ions to the reaction site, and facilitates easy removal of precipitated brucite by simply stopping the rotation and scraping. This dynamic approach significantly improves production rate and simplifies product recovery compared to static precipitation methods.

Inventive Principle:

Principle #15Dynamics

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 process enhances seawater's carbon storage capacity by increasing pH, allowing for effective CO2 uptake and reducing energy requirements, maintenance costs, and operational expenses.

Implementation Method 1

contacting the catholyte with an electroactive mesh cathode to electrolytically generate hydroxide ions, thereby precipitating the one or more hydroxide solids

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

electrolytically generate hydroxide ions, thereby precipitating the one or more hydroxide solids

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS20250313966A1Seawater electrolysis enables mg(OH)2 production and co2 mineralization

Publication Date: 2025.10.09 RGT UNIV OF CALIFORNIA

AI summary

A method for producing one or more hydroxide solids includes providing a catholyte comprising an electrolyte solution; contacting the catholyte with an electroactive mesh cathode to electrolytically generate hydroxide ions, thereby precipitating the one or more hydroxide solid(s); and removing the one or more hydroxide solids from the surface of the mesh where they may deposit.