The invention is directed to a method for recovering lactose from an aqueous lactose solution comprising a concentration step, wherein water is removed from the aqueous lactose solution by freezing out water at a temperature below the eutectic temperature of the aqueous lactose solution and at a lactose concentration higher than the eutectic concentration of the aqueous lactose solution, thereby obtaining a concentrated lactose solution; and a crystallization step, wherein at least part of the concentrated lactose solution is subjected to crystallization at a temperature above the eutectic temperature of the concentrated lactose solution, thereby obtaining lactose crystals.

Disclosed is a method for preparing adrenochrome by catalytic oxidation using nitrogen-doped carbon nanotubes. The method catalyzes dissolved oxygen in an aqueous solution by the nitrogen-doped carbon nanotubes to rapidly oxidize adrenaline, which is completely transformed into adrenochrome. It is a novel preparation process of adrenochrome, which is simple, and has mild reaction conditions, high product purity, an impurity content less than 10.sup.−8%, and low subsequent processing cost, thereby having a great application prospect. The nitrogen-doped carbon tubes after use can be regenerated and recovered, and its reutilization is still able to realize the complete transformation of adrenaline. The high utilization rate of catalytic material conforms to the concept of energy conservation, minimizing the costs.

Disclosed is a method for preparing adrenochrome by catalytic oxidation using nitrogen-doped carbon nanotubes. The method catalyzes dissolved oxygen in an aqueous solution by the nitrogen-doped carbon nanotubes to rapidly oxidize adrenaline, which is completely transformed into adrenochrome. It is a novel preparation process of adrenochrome, which is simple, and has mild reaction conditions, high product purity, an impurity content less than 10.sup.−8%, and low subsequent processing cost, thereby having a great application prospect. The nitrogen-doped carbon tubes after use can be regenerated and recovered, and its reutilization is still able to realize the complete transformation of adrenaline. The high utilization rate of catalytic material conforms to the concept of energy conservation, minimizing the costs.

A method for highly concentrating aqueous solutions containing thermally sensitive organic constituents and with or without mineral constituents, wherein firstly, a major portion of the water is extracted by membrane filtration from the solution for pre-concentration and is discharged from the process and the solution which is pre-concentrated is then subjected to a freeze concentration procedure, in which, in the form of separated ice crystallisate, further water is extracted from the solution. To promote results, that concentration may be effected in the freeze concentration procedure until a viscosity of the mother solution of at least 0.0002 m.sup.2/s is achieved, and in that the separated ice crystallisate from the freeze concentration with the mother solution adhering thereto as a suspension is returned to the membrane filtration upstream of the membrane filtration or after melting of the ice crystallisate.

A method for highly concentrating aqueous solutions containing thermally sensitive organic constituents and with or without mineral constituents, wherein firstly, a major portion of the water is extracted by membrane filtration from the solution for pre-concentration and is discharged from the process and the solution which is pre-concentrated is then subjected to a freeze concentration procedure, in which, in the form of separated ice crystallisate, further water is extracted from the solution. To promote results, that concentration may be effected in the freeze concentration procedure until a viscosity of the mother solution of at least 0.0002 m.sup.2/s is achieved, and in that the separated ice crystallisate from the freeze concentration with the mother solution adhering thereto as a suspension is returned to the membrane filtration upstream of the membrane filtration or after melting of the ice crystallisate.

Disclosed is a method for preparing adrenochrome by catalytic oxidation using nitrogen-doped carbon nanotubes. The method catalyzes dissolved oxygen in an aqueous solution by the nitrogen-doped carbon nanotubes to rapidly oxidize adrenaline, which is completely transformed into adrenochrome. It is a novel preparation process of adrenochrome, which is simple, and has mild reaction conditions, high product purity, an impurity content less than 10.sup.−8%, and low subsequent processing cost, thereby having a great application prospect. The nitrogen-doped carbon tubes after use can be regenerated and recovered, and its reutilization is still able to realize the complete transformation of adrenaline. The high utilization rate of catalytic material conforms to the concept of energy conservation, minimizing the costs.

Disclosed is a method for preparing adrenochrome by catalytic oxidation using nitrogen-doped carbon nanotubes. The method catalyzes dissolved oxygen in an aqueous solution by the nitrogen-doped carbon nanotubes to rapidly oxidize adrenaline, which is completely transformed into adrenochrome. It is a novel preparation process of adrenochrome, which is simple, and has mild reaction conditions, high product purity, an impurity content less than 10.sup.−8%, and low subsequent processing cost, thereby having a great application prospect. The nitrogen-doped carbon tubes after use can be regenerated and recovered, and its reutilization is still able to realize the complete transformation of adrenaline. The high utilization rate of catalytic material conforms to the concept of energy conservation, minimizing the costs.

It is an object of the present invention is to obtain a solid-liquid distribution detecting apparatus that detects solid-liquid distribution in a solid-liquid separation column. A solid-liquid distribution detecting apparatus (20) of the present invention detects solid-liquid distribution of a content in a solid-liquid separation column (10) of a freeze concentration device and includes a sound source (21) that emits a sound wave to the column surface of the solid-liquid separation column (10), a measuring device (22) that measures a resonance waveform on the surface of the column, and an analysis device (24) that analyzes the resonance waveform measured by the measuring device (22) and determines a solid-liquid distribution state of the content in the solid-liquid separation column based on the analysis result.

It is an object of the present invention is to obtain a solid-liquid distribution detecting apparatus that detects solid-liquid distribution in a solid-liquid separation column. A solid-liquid distribution detecting apparatus (20) of the present invention detects solid-liquid distribution of a content in a solid-liquid separation column (10) of a freeze concentration device and includes a sound source (21) that emits a sound wave to the column surface of the solid-liquid separation column (10), a measuring device (22) that measures a resonance waveform on the surface of the column, and an analysis device (24) that analyzes the resonance waveform measured by the measuring device (22) and determines a solid-liquid distribution state of the content in the solid-liquid separation column based on the analysis result.

An apparatus for generating dialysate for dialysis comprising a dialysate outlet and a dialysate inlet and dialysate purifying means, wherein the purifying means comprise a cryopurifier for generating pure water, wherein the inlet of the cryopurifier is connected to the dialysate outlet and the outlet of the cryopurifier is connected to the dialysate inlet; and a method for reclaiming of fresh dialysate from ultrafiltrate and wasted dialysate extracted from a dialysis patient, comprising the following steps: preparing an ice slurry from the dialysate, wherein the ice slurry contains ice crystals and a liquid containing solutes; and separating the ice crystals from the liquid containing the solutes.