The present invention provides a method for hemodiafiltration which applies dialysate gradient across a multi-chambered hemodiafiltrator having a plurality of compartmentalized tubular dialysate chambers. An acidic dialysate with urea at a concentration is applied to a first dialysate chamber. A less acidic dialysate with a lower concentration of urea than those for the first dialysate chamber is applied to a second dialysate chamber. A basic dialysate with no urea but with ammonia at a concentration up to a concentration detected in normal human blood is applied to a last dialysate chamber. The concentrations of urea for the first and second dialysate chambers decrease over time to zero prior to conclusion of hemodiafiltration.

An electrodialytic battery system comprises an electrodialysis apparatus having first and second reservoirs, wherein concentration of an input solution in the first reservoir increases and concentration of the input solution decreases in the second reservoir during an operation mode. A first redox-active electrolyte chamber comprises a first electrode and a first solution of a first redox-active electrolyte material and has a reversible redox reaction with the first electrolyte material to drive an ion into the first reservoir. A second redox-active electrolyte chamber comprises a second electrode and a second solution of a redox-active electrolyte material and has a reversible redox reaction with the second electrolyte material to accept an ion from the second reservoir. A first type of membrane is disposed between the first and second reservoirs, and a second type of membrane, different from the first type, is disposed between the respective electrode chambers and reservoirs.

This document describes systems and methods for treating and recovering water from feed solutions using a membrane module that has a plurality of hollow fiber membranes encapsulated in a collection chamber and an expansion chamber that is connected to the outlet of the membrane module.

The invention relates to a dialysis cell for sample preparation for a chemical analysis method, in particular for ion chromatography. The dialysis cell comprises a donor channel and an acceptor channel extending parallel thereto. The donor channel and the acceptor channel are separated from each other by a selectively permeable dialysis membrane. In particular, an analyte that is dissolved in a donor solution in the donor channel can enter through the dialysis membrane into the acceptor solution in the acceptor channel. The acceptor channel has at least in some sections a volume that is smaller than the volume of the donor channel extending parallel thereto. Acceptor and donor channels are formed from half-cells, between which the dialysis membrane is arranged, wherein the donor channel and the acceptor channel are designed in each case as a recess in a contact surface of one of the half-cells with the dialysis membrane.

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 continuous CO.sub.2 capture system, method, and device are disclosed. The device includes a CO.sub.2 pump membrane including a moisture-swing material, and a cavity having a first fluid. The CO.sub.2 pump membrane separates the first fluid from a second fluid, the fluids creating a water concentration gradient across the membrane and transport of water through the membrane. The water concentration gradient creates a carbon concentration gradient across the membrane that decreases moving from outside the cavity to inside the cavity. As water is continuously transported from the first fluid to the second fluid through the CO.sub.2 pump membrane because of the water concentration gradient, carbon dioxide is continuously captured from the second fluid by the moisture-swing material of the CO.sub.2 pump membrane and continuously pumped along the carbon concentration gradient across the CO.sub.2 pump membrane and into the first fluid within the cavity.

A liquid desiccant regeneration system comprises an electrodialysis apparatus having first and second reservoirs, wherein concentration of an input solution in the first reservoir increases to a threshold concentration and concentration of the input solution decreases in the second reservoir during an operation mode. A first redox-active electrolyte chamber comprises a first electrode and a first solution of a redox-active electrolyte material and has a reversible redox reaction with the first electrolyte material to drive an ion into the first reservoir. A second redox-active electrolyte chamber comprises a second electrode and a second solution of a redox-active electrolyte material and has a reversible redox reaction with the second electrolyte material to accept an ion from the second reservoir. A first type of membrane is disposed between the first and second reservoirs, and a second type of membrane, different from the first, is disposed between the respective electrode chambers and reservoirs.

A system comprises an electrodialysis apparatus, which includes first and second reservoirs, wherein a salt concentration in the first reservoir reduces below a threshold concentration, and salt concentration in the second reservoir increases during an operation mode. A first electrode comprises a first solution of a first redox-active electrolyte material, and a second electrode comprises a second solution of a second redox-active electrolyte material. In a first reversible redox reaction between the first electrode and first electrolyte material at least one ion is accepted from the first reservoir, and in a second reversible redox reaction between the second electrode and second electrolyte material at least one ion is driven into the second reservoir. A first type of ion exchange membrane is disposed between the first and second reservoirs, and a second type of ion exchange membrane, different from the first type, is disposed between the respective electrodes and reservoirs.

[Object] To provide a method for isolating and purifying a minute useful substance. [Solution] Disclosed is a method for isolating and purifying a minute useful substance. The method includes filtering a liquid containing a minute useful substance through a hollow fiber membrane. The hollow fiber membrane has an inner diameter of 0.2 mm to 1.4 mm and a molecular weight cut-off of 100000 to 1000000. The filtering includes a first filtration process of press-fitting the liquid containing the minute useful substance from a first opening on one end side of the hollow fiber membrane and filtering the liquid to separate the liquid into a permeate and a first concentrate, and a second filtration process of press-fitting the first concentrate from a second opening on the other end side of the hollow fiber membrane and filtering the first concentrate to separate the first concentrate into a permeate and a second concentrate. A concentrate is produced in which a concentration of the minute useful substance is increased by filtration in which the first filtration process and the second filtration process are alternately performed a plurality of times at a membrane surface velocity of 0.3 m/sec to 2 m/sec.

A micro flow filtration system comprises a fluid circuitry (3) and a first reservoir (1) outside the circuitry (3) suitable for containing a fluid. The fluid circuitry (3) comprises a tangential flow filtration module (10) capable of separating the fluid sample into a retentate stream and a permeate stream upon passage of the fluid sample into the tangential flow filtration module (10) through an inlet feed (18). The fluid circuitry (3) further comprises a second reservoir (2) integrated in the fluid circuitry (3), a pump (5) for creating and driving a fluid flow, optionally at least one pressure sensor (6, 7 or 8) for acquiring and detecting data about the fluid sample, optionally a pressure regulator (9) for regulating the flow in the fluid circuitry (3) and a plurality of conduits (22) forming the fluid circuitry (3) together with the second reservoir (2), the TFF-module (10), the pump (5), the pressure sensor (6, 7 or 8) (if present) and the pressure regulator (9) (if present). The volume of the first reservoir (1) outside the circuitry (3) is significantly larger than the volume of the second reservoir (2). The first reservoir (1) outside the fluid circuitry (3) is connected to the circuitry (3) via a connection conduit (31) such that the fluid flows unidirectionally into the circuitry (3) until the first reservoir (1) is empty so that a continuous fluid flow from the first reservoir (1) to the circuitry (3) is established.