REACTIVE ELECTROCHEMICAL MEMBRANE FILTRATION
Abs: Physical membrane separation suffers from membrane fouling due to the deposition and adsorption of various foulants. Frequent membrane backwashing and cleaning is required to maintain a desired separation and functional filtration, which elevates the operational cost. The reactive electrochemical membrane (REM) technology will use low level direct current (DC) to control and mitigate membrane fouling during filtration or backwash to better recover flux.
Physical membrane separation suffers from membrane fouling due to the deposition and adsorption of various foulants. Frequent membrane backwashing and cleaning is required to maintain a desired separation and functional filtration, which elevates the operational cost. Usually, hydraulic flushing, biocides or harsh chemical cleaners are used to recover permeate flux, which are costly and potentially harmful to membrane integrity or life span. The reactive electrochemical membrane (REM) technology will use low level direct current (DC) to control and mitigate membrane fouling during filtration or backwash to better recover flux. Many prior research including ours demonstrated the use of REM membrane in various forms (i.e., monolithic porous ceramics, electrospun mats of nanofibers, and carbon nanofibers loaded with conductive nanomaterials) as both electrodes and membrane filter could have could have anodic or cathodic polarization under DC current and therefore could efficiently oxidize organic compounds or surface foulants by hydroxyl radical (•OH) produced from water oxidation. Compared to regular ceramic membrane filtration, electrochemical ceramic membranes will bring more measurable synergies, including but not limited to: durable and stable permeate flux across ceramic membrane without significant fouling over a larger period of time, degradation of organic pollutants or compounds in the treated water, and reduction in membrane fouling and energy use for backwash for recovery of flux. These features are usually not all available in one integrated membrane process.
The REM technology holds high commercialization potential because (1) ceramic membranes and conductive membranes are already implemented in many industrial water and wastewater treatment in various fields (e.g. pharmaceutical wastewater, dye and mining wastewater treatment). Thus, REM could be conveniently deployed and upgrade the existing ceramic membrane modules. (2) The increasing demand for high water quality in many industrial applications. For example, semiconductor production requires ultra-high purity water and has a great demand for reliable and high efficient filtration systems to eliminate water pollutants such as salts, particles, and organics. (3) Conventional polymer membrane filtration suffers inherent limitations in fouling, aging, and instability in the treatment of complex water (e.g., corrosive or high salt content waters). (4) A benchmark innovation in reactive ceramic filtration will advance and potentially upgrade the filtration industries from physical separation to versatile and tunable reactive separation, which is interesting and attractive to customers we interviewed in the past.
This technology represents a potentially game-changing filtration technology that is designed to improve water filtration efficiency, lower fouling potential (increased durability and stability), enabling high fluxes of water permeate and pre-oxidation of organic substituents. Accordingly, may provide value propositions in saving the capital costs on membrane backwash, membrane maintenance, reduce down time or off-line time, and reduce chemical uses for membrane cleaning, and replacement of membranes that are fouled or aged; decrease pumping energy; increase water quality by efficiently removing phenols in water based on electrochemical oxidation reactions on REM surfaces.