Description:
Reference #: 1686
The University of South Carolina is offering licensing opportunities for Electrochemical ion extraction apparatus comprising ion selective membrane.
Background:
The present invention relates generally to the field of mining valuable mineral ions from an aqueous phase. Particularly, the present invention describes an electrochemical ion extraction apparatus comprising ion selective membrane and its applications in the field, including but not limited to selective ions extraction from seawater/brine water for valuable minerals production/recycling and isotope separation.
Currently, many valuable metals, like lithium, are mainly obtained from ores. Mining ores is usually time and capital costly and disastrous for the local environment. Considering both the amounts of ores and the access to ores are limited, their extraction from other sources is a must. Seawater has the world's largest amount of various valuable metals in their ions form, but many of their concentrations in seawater are relatively low. Meanwhile, there exist interfering ions, such as Mg2+, Ca2+, and Na+, which cause difficulty and cost-effectiveness issue for mineral mining from seawater. The main traditional methods of metal ion extraction from salt lakes in the world are extraction, adsorption, salt-field enrichment precipitation, calcination infiltration, and sun pond method; each of them is limited by its own drawbacks such as long operation time, requirement of a large area, or vast chemical byproduct. Thus, recent research methods including the membrane method and electrochemical method, are receiving more and more attention.
Nanofiltration processes are commonly used in membrane extraction techniques to pre-concentrate and extract metal ions from seawater/brine water. Mass transfer in nanofiltration is mainly affected by factors such as Donnan exclusion and dielectric exclusion. However, nanofiltration methods have low selectivity for monovalent ions, which restrains their capability to extract valuable monovalent ions such as Li+. Electromigration employed with ion exchange membranes (IEMs) has been widely used in seawater desalination and ion separation. However, current commercial IEMs do not have sufficient ion selectivity to separate or extract metal ions. Therefore, membranes with high selectivity towards target ion is crucial for metal ion extraction via electromigration.
Invention Description:
The present invention provides a novel Flow Electrode Extraction (FEE) apparatus employing ion-selective ceramic membranes (ICMs) that successfully overcome the difficulties of seawater/brine water extraction and can be applied for selectively pre-concentrating and extracting metal ions. In the invented FEE apparatus, an aqueous flow electrode comprising carbon-based or redox chemical-based electrolyte is used. The flow electrode is circulated between the anode and cathode current collectors during operation. With an applied cell voltage, the flow electrode materials are charged or discharged at the respective current collector surface, forcing cations and anions to move from one water chamber to another through the ion-selective ceramic membrane (ICM) to neutralize the extra charge generated by the charging or discharging process, resulting in the concentrating of ions in one of the chambers. A variety of ceramic materials, including but not limited to oxides, sulfides, selenides, phosphates, silicates, perovskites, zeolites, layered hydroxides, as well as their composites with polymers, are ion-specific conductive and can be used as ICM in the FEE apparatus for ion-selective extraction. Taking Li ion mining as an example, ceramic membranes like LiFePO4 and perovskite-type materials (like LLTO), with their unique crystal structure that forms tunnels to allow only Li ions jumping from one site to another, can be used as ICM for selective Li ion extraction from seawater/brine water.
Potential Applications:
Valuable metal extraction from aqueous sources, desalination
Advantages and Benefits:
The electrode materials of the invention are made of low-cost and carbon based materials. The invention can be operated using standard electrical power, which can be easily converted to other green-energy sources such as solar panels and wind-driven generators. A range of valuable isotopes and ions can be isolated using this extracted method in a more efficient and cost-effective way