348 results about "Electrodeionization" patented technology

A method and apparatus is provided for inhibiting scaling in an electrodeionization system and, more particularly, for increasing tolerance to hardness in the feed water to an electrodeionization unit by inhibiting precipitation of scale-forming metallic cations contained in the feed water and thereby increasing efficiencies of the electrodeionization system. Water to be purified is passed through an electrodeionization unit in which the flow in the diluting compartment is countercurrent to the flow in the concentrating compartment. This is to impede the migration of scale-forming metallic cations from the diluting compartment, through the cation exchange membrane, into the concentrating compartment and towards the concentrating compartment side of the anion exchange membrane, thereby preventing scale formation on the anion exchange membrane. The electrodeionization unit may be further modified by dividing the concentrating compartments into first and second compartments by a porous diaphragm or ion-conducting membrane. The porous diaphragm or ion-conducting membrane effectively eliminates convective transport of scale-forming metallic cations from the cation exchange membrane side of the concentrating compartment to the anion exchange membrane side of the concentrating compartment, thereby inhibiting scale formation on the anion exchange membrane.

The present invention is directed to a water treatment or purification system and method for providing treated water in industrial, commercial and residential applications. The treatment system provides treated or softened water to a point of use by removing at least a portion of any hardness-causing species contained in water from a water source, such as municipal water, well water, brackish water and water containing foulants. The water treatment system includes an electrochemical device, such as an electrodeionization device, that can have at least one compartment that generates and traps hydrogen ions which can be used in another compartment of the electrochemical device such as, an electrode compartment, to reduce or at least dissolve any scale. Other applications of the system would be in the treatment and processing of foods and beverages, sugars, various industries such as the chemical, pharmaceutical, waste water treatment and power generating industries.

A deionized water producing apparatus includes a pretreatment apparatus having a reverse osmosis apparatus, and an electrodeionization apparatus having a diluting compartment filled with an ion exchanger. In order to disinfect the deionized water producing apparatus, hot water of higher than 80° C. is flown through the pretreatment apparatus, and hot water of higher than 60° C. is flown through the electrodeionization apparatus. Hot water flowing thorough the electrodeionization apparatus is gradually heated at a rate of 0.1-10° C./min.

A low energy water treatment system and method is provided. The system has at least one electrodialysis device that produces partially treated water and a brine byproduct, a softener, and at least one electrodeionization device. The partially treated water stream can be softened by the softener to reduce the likelihood of scale formation and to reduce energy consumption in the electrodeionization device, which produces water having target properties. At least a portion of the energy used by the electrodeionization device can be generated by concentration differences between the brine and seawater streams introduced into compartments thereof. The brine stream can also be used to regenerate the softener.

A method and apparatus for purifying water are provided. A feed water such as seawater can be fed to a filter such as a microporous or nanofiltration membrane to produce a permeate that can, in turn, be fed to an electrodeionization system to produce fresh water.

Water purification systems include a concentrate filtration membrane and an electrodeionization unit. A concentrate effluent stream from the electrodeionization unit is filtered in the concentrate filtration membrane; the filtered concentrate effluent stream is provided to concentrating compartments of the electrodeionization unit.

An electrodeionization apparatus is provided comprising an ion-concentrating compartment partially bounded by an anion permeable membrane and also partially bounded by a cation permeable membrane, and a first ion exchange material domain disposed within the ion-concentrating compartment, wherein the first ion exchange material domain is contiguous with at least a portion of an ion-concentrating compartment side surface of one of the anion permeable membrane and the cation permeable membrane, and is spaced apart from the other one of the one of the anion permeable membrane and the cation permeable membrane. In the case where the one of the anion permeable membrane and the cation permeable membrane, having the at least a portion of an ion-concentrating compartment side surface with which the first ion exchange material domain is contiguous, is an anion permeable membrane, the first ion exchange material domain is an anion exchange material predominant domain. In the case where the one of the anion permeable membrane and the cation permeable membrane, having the at least a portion of an ion-concentrating compartment side surface with which the first ion exchange material domain is contiguous, is a cation permeable membrane, the first ion exchange material domain is a cation exchange material predominant domain.

An electrodeionization, (EDI) apparatus has flow cells with a sparse distribution of ion exchange (IX) material or beads. The beads extend between membranes defining opposed walls of the cell to separate and support the membranes, and form a layer substantially free of bead-to-bead dead-end reverse junctions. The beads enhance capture of ions from surrounding fluid in dilute cells, and do not throw salt when operating current is increased. In concentrating cells, the sparse bead filling provides a stable low impedance bridge to enhanced power utilization in the stack. A monotype sparse filling may be used in concentrate cells, while mixed, layered, striped, graded or other beads may be employed in dilute cells. Ion conduction paths are no more than a few grains long and the lower packing density permits effective fluid flow. A flow cell thickness may be below one millimeter, and the beads may be discretely spaced, form a mixed or patterned monolayer, or form an ordered bilayer, and a mesh having a lattice spacing comparable to or of the same order of magnitude as resin grain size, may provide a distributed open support that assures a stable distribution of the sparse filling, and over time maintains the initial balance of uniform conductivity and good through-flow. The cells or low thickness and this resin layers relax stack size and power supply constraints, while providing treatment efficiencies and process stability. Reduced ion migration distances enhance the ion removal rate without reducing the product flow rate. The sparse resin bed may be layered, graded along the length of the path, striped or otherwise patterned. Inter-grain ion hopping is reduced or eliminated, thus avoiding the occurrence of salt-throwing which occurs at reverse bead junctions of prior art constructions. Conductivity of concentrate cells is increased, permitting more compact device construction, allowing increases in stack cell number, and providing more efficient electrical operation without ion additions. Finally, ion storage within beads is greatly reduces, eliminating the potential for contamination during reversal operation. Various methods of forming sparse beds and assembling the stacks are disclosed.

Systems and methods for removing hydrogen peroxide from water purification systems are provided. In a general embodiment, the present disclosure provides a water purification system including a water treatment unit, an electrodeionization unit and a hydrogen peroxide decomposition catalyst in fluid connection with the electrodeionization unit. The water purification system can be fluidly connected to a renal treatment system.

The present disclosure generally relates to methods, systems, and devices for electrically purifying liquids containing species such as minerals, salts, ions, organics, and the like. One aspect of the invention provides an electrical purification apparatus, including an electrodeionization device. The electrodeionization device may be run in any suitable fashion, for example, continuously or essentially continuously, intermittently, upon demand, with periodic reversals of polarity. In another aspect, methods of regenerating media within an electrical purification device are provided, for example, exposing the media to one or more eluting solutions, and/or selectively desorbing ions, organics, and/or other species from the media by exposing the media to certain eluting conditions. In yet another aspect, methods of selectively removing one or more ions, organics, and/or other species from a liquid to be purified are provided, by selective removal of one or more ions, or organics, and the like from solution that can easily precipitate, and/or cause scaling or fouling to occur. In still another aspect, the invention provides a method of treating a solution containing ions, organics, and/or other species using an electrical purification apparatus in a continuous or semi-continuous fashion, while also performing regeneration of media contained within the apparatus.

A liquid treatment process is described for sequential removal of ionic species of progressively decreasing ionic strength without precipitation or “scaling.” An aspect of the invention includes dual electrodeionization operations. The first electrodeionization operation is performed at a voltage calculated to remove strongly ionized species such as calcium and magnesium from the feed water without scaling. The product of the first electrodeionization operation is then subjected to a second electrodeionization operation. The second electrodeionization operation is performed at a voltage greater than the first electrodeionization operation, and is designed to remove more weakly ionized species such as silica and carbon dioxide, preventing scaling. More than two successive electrodeionization operations may be performed if desired. Multiple electrodeionization operations may occur in a single electrodeionization stack or in multiple electrodeionization stacks.

A water treatment system and method including a membrane-based boron removal unit includes a boron analyzer for detecting the concentration of boron in a treatment stream. The boron removal unit can be a reverse osmosis (RO) or electrodeionization (EDI) treatment unit. A controller responds to the detected boron concentration to control an operation of the RO or EDI units. In an EDI system, the controller may adjust current or voltage supplied to match current to changes in ionic load and maintain a portion of the dilute cell in a substantially regenerated state. In an RO system, the controller may control the high pressure side flow rate, the brine blowdown rate, the product water permeation rate, pH, or feed rate of chemicals in response to the detected boron concentration value.

Water purification systems include a reverse osmosis unit, a treatment unit, and an electrodeionization unit. A reverse osmosis reject stream from the reverse osmosis unit is treated in the treatment unit and provided to concentrating compartments of the electrodeionization unit.

A low energy system and process for seawater desalination wherein the system has at least an electrodialysis apparatus that produces partially desalinated water and a brine by-product, an ion exchange softener, and at least one electrodeionization apparatus. The softener treats the partially desalinated water stream to remove or reduce the amount of scaling material in order to maintain deionization apparatus efficiency and reduce energy consumption. The softener has the capability of removing a higher ratio of calcium ions to magnesium ions than is in the partially desalinated stream, thereby reducing softener size and energy use. The deionization apparatus produces product water of the desired properties. The brine stream may be used to regenerate the softener.

The present invention pertains to a method of ion chromatography wherein a specialized electrodeionization (EDI) apparatus is used for (1) the preparation of a pure acid or pure base for use as an eluent in a chromatographic separation column and/or (2) for ion suppression (or neutralization) of the acid or base after it has been used to elute ions from a chromatographic separation column. Methods for trace ion removal, acid and base neutralization, and ion suppression using a specialized EDI apparatus are also described. The methods described herein allow for the ion suppression of samples containing chloride, nitrate, and other electrochemically active anions, without causing damage to the suppressor.

The present invention provides a method and apparatus for purifying effluent wastewater utilizing electrophoretic cross-flow filtration and electrode ionization. The method first comprises filtering the water in a cross-flow direction with a filter membrane in the presence of an electric field that is operative to drive suspended particles away from a surface of the filter membrane. The permeate containing dissolved solids is next passed through a mixture of at least one cation-exchange resin and at least one anion-exchange resin disposed between a cation-selective membrane and an anion-selective membrane in the presence of an electric field. The electric field drives cations in the permeate through the cation-selective membrane, and drives anions in the permeate through the anion-selective membrane, thereby to form deionized water. The apparatus includes cell modules adapted to be used in plate-and-frame or radial flow configurations.

The present invention provides a resin-wafer electrodeionization (RW-EDI) apparatus including cathode and anode electrodes separated by a plurality of porous solid ion exchange resin wafers, which when in use are filled with an aqueous fluid. The apparatus includes one or more wafers comprising a basic ion exchange medium, and preferably includes one or more wafers comprising an acidic ion exchange medium. The wafers are separated from one another by ion exchange membranes. The fluid within the acidic and/or basic ion exchange wafers preferably includes, or is in contact with, a carbonic anhydrase (CA) enzyme to facilitate conversion of bicarbonate ion to carbon dioxide within the acidic medium. A pH suitable for exchange of CO₂ is electrochemically maintained within the basic and acidic ion exchange wafers by applying an electric potential across the cathode and anode.

Apparatus and method are disclosed for introducing ion exchange or other particulates into compartments of an already-assembled electrodeionization or comparable stack by modulating a flow of slurry into the compartments with slugs of gas such as air. The air propels liquid through the cells, scavenging ponded liquid so that the particulates (which are retained, e.g., by a strainer or obstruction, in compartment of the apparatus) are deposited as well-packed beds to fill the compartments. Pressurized air filling protocols may deliver discrete slugs of slurry between bursts of air, and the direction of filling may be periodically reversed to diminish particle bed non-homogeneities or settling gradients that arise during transport. The slugs of air may be applied in the direction of slurry flow, in the reverse direction, or both. Different slurries may be transported in a sequence to form layered and packed beds of enhanced utility. An apparatus of the invention has filled compartments of enhanced packing, and is ported or has its passages arranged so that ion exchange material may be filled, or may be replenished by a fluidized flow according to a method of this invention.

The invention discloses an electrodeionization (EDI) method and system dispensing with ion exchange membranes. The system is characterized in that porous water distribution plates, top electrodes, ion exchange resins, bottom electrodes and porous floating blocks with density less than that of water are placed in an insulating cavity from top to bottom in sequence; a top cover and the upper ends of cylindrical shells are sealed by upper seal rings; a bottom cover and the lower ends of the cylindrical shells are sealed by lower seal rings; the porous water distribution plates and the top electrodes are fixed between the top cover and the end faces of the cylindrical shells; the bottom electrodes are fixed on the porous floating blocks; intermediate seal rings are installed between the porous floating blocks and the cylindrical shells; and the top and bottom electrodes are respectively connected with a high-voltage direct current power supply. The method and the system have the following beneficial effect: the problems of membrane pollution, concentration polarization, scaling, hydroxide precipitates formed on the membrane surfaces when the heavy metal wastewater containing Cu<2+>, Ni<2+> and other ions are treated because the ion exchange membranes are adopted for EDI are solved. The method and the system are suitable for preparation of highly pure water, purification of electroplating rinse wastewater containing heavy metal ions and treatment of water and wastewater aiming at removing the ionic impurities.