RU2426305C1 - Mix for forming acetilation pulp ultra filtration membrane (versions) - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: invention relates to food industry and may be used for lactoserum proteins separation. Proposed mix consists of cellulose diacetate in acetone and millet thrashing wastes thermally treated at t=200-400C with no oxygen that have particle sized of 85 mcm at the following content of components, wt %: cellulose diacetate - 5.0, acetone - 62.6-68.5, millet thrashing wastes thermally treated - 26.5-32.4. In using thermally treated millet thrashing wastes with particle size of 160 mcm, proposed mix features the following content of components, wt%: cellulose diacetate - 7.0, acetone - 67.7-78.5, millet thrashing wastes thermally treated - 14.5-25.3. ^ EFFECT: higher sensitivity of membranes. ^ 2 cl, 1 tbl, 1 ex

Description

The invention relates to membrane materials and technologies and can be widely used for the separation of multicomponent liquids, especially in the food industry for the isolation of whey proteins and their fractions from whey.

A known mixture for forming industrial ultrafiltration membrane UAM from cellulose acetate and solvents. The membrane has a selective filter layer with a thickness of about 10 nm and a large-pore base with a thickness of 5 · 10 ⁴ nm. Cellulose acetate membranes are the most compatible with food products / Dubyaga V.P. et al. Polymeric membranes - M .: Chemistry. - 1981. - 216 p. /.

A significant disadvantage of the membranes from the above mixture is their low permeability and selectivity, which does not exceed 62% for whey proteins and their fractions.

A known mixture for forming an ultrafiltration membrane, representing 5%; 10%; 15% solution of cellulose acetate in acetone. The membrane obtained from such a mixture is a homogeneous cellulose acetate fine-porous film with a thickness of (16-17) · 10 ⁴ nm. Permeability at 20 ° C and a pressure of 0.2 MPa is 0.48-0.72 l / m ² · min. The selectivity for whey protein does not exceed 72.0% / patent No. 2093255 of the Russian Federation, publ. 10.20.1997 /.

When using a membrane from such a mixture for ultrafiltration of whey, insufficient selectivity is observed for individual protein fractions.

The closest technical solution is a mixture for the formation of cellulose acetate ultrafiltration adsorption membrane containing a solution of cellulose diacetate in acetone and a particulate filler - activated charcoal in the following components, wt.%:

cellulose diacetate 5,0 acetone 62.6-68.5 activated wood coal with a particle size of 85 microns 26.5-32.4

or

cellulose diacetate 7.0 acetone 67.7-78.5 activated wood coal with a particle size of 160 microns 14.5-25.3

/ patent No. 2287929 of the Russian Federation, publ., bull. No. 33 dated 05/10/2006 /

The main disadvantage of the technical solution of the prototype is the wide variation in pore size and low selectivity for fractions of whey proteins.

When creating the invention, the task was to increase the selectivity of membranes both in whey proteins and in their individual fractions.

To achieve the task and obtain a technical result, a mixture for molding cellulose acetate ultrafiltration membrane containing a solution of cellulose diacetate in a solvent acetone and a dispersed filler in the following components, wt.%:

cellulose diacetate 5,0 acetone 62.6-68.5 particulate filler with a particle size of 85 microns 26.5-32.4

or

cellulose diacetate 7.0 acetone 67.7-78.5 particulate filler with a particle size of 160 microns 14.5-25.3;

as a dispersed filler, the mixture contains heat treated at th = 200-400 ° С without oxygen access threshing millet (OOP).

The invention is carried out as follows.

Membranes are made on the basis of 5% and 7% solutions of cellulose diacetate (DAC) in acetone. As a filler, heat-treated waste of threshing millet of two fractions of 85 microns and 160 microns is used.

Example. To prepare a 5% solution of DAC in acetone, it is necessary to take 5 g of DAC and 95 g of acetone.

The density of acetone is ρ _AC = 0.79 g / ml.

Therefore, 95 g of acetone will be 95 g / 0.79 g / ml = 120 ml.

A portion of the solution is prepared in a volume of 200 ml:

120 ml of acetone - 5 g of DAC

200 ml of acetone - X g DAC

X = 8.34 g DAC

For the solution, a 7% concentration of DAC is 11.8 g.

In the manufacture of the molding mixture, 50 ml of a DAC solution in acetone is measured, a filler is added - heat treated at t = 200-400 ° C without access of oxygen, threshing millet wastes. In this temperature range, the structure of the filler particles varies slightly. At temperatures below 200 ° C, some undecomposed organic products are retained in OOP, which negatively affects the structure of the membrane. At temperatures above 400 ° C, the destruction of the dispersed filler begins, leading to a change in its chemical composition. Then the mixture of DAC, acetone and filler is stirred until a homogeneous molding solution is formed, which is divided into 10 ml portions and the membranes are cast from them. Membrane formation occurs at t = 20 ° C for 24 hours. In this case, acetone slowly evaporates from the entire volume of the molding mixture with the formation of a finely porous membrane structure.

Table 1 shows data on examples of the composition of the mixture for the formation of cellulose acetate ultrafiltration membranes, as well as data on the permeability and selectivity of the membranes for distilled water and whey.

Membrane permeability was determined by the flow method, and their selectivity for protein and individual fractions was determined by chemical methods.

A significant difference between the membranes of the claimed mixture is their high selectivity for whey proteins and their fractions, due to the presence in the molding mixture of heat-treated waste threshed millet.

This mixture has several advantages over the prototype:

- increases the selectivity of membranes for serum proteins from 63% to 88%;

- sufficient membrane selectivity for the main fractions of whey proteins is manifested:

by α-lactalbumin - 62%;

β-lactoglobulin - 78%;

bovine serum albumin - 89%;

lactoferrin - 92%;

immunoglobulin - 97%.

In addition, the use of millet threshing waste as a dispersed filler can significantly reduce the cost of filler production, and therefore the cost of products, as well as use environmentally friendly raw materials.

Table 1 No. p / p DAC, wt.% Acetone, wt.% Filler - waste threshing millet, wt.% Particle size dispersed floor
carrier, microns Poris
toast,% Whey protein selectivity,% Permeability, l / m ² · h By distilliro
bath water For whey one 5 84.1 10.9 85 11.85 fifty 41.3 25,4 2 75.7 19.3 13.15 62 70.5 52.6 3 68.5 26.5 17.17 88 114.68 91.25 four 62.6 32,4 22.5 75 250.25 212.75 5 7 85,2 7.8 160 12.7 71 61.25 27,2 6 78.5 14.5 15,52 84 94.72 34,4 7 72.7 20.3 17.00 80 120.45 48.6 8 67.7 25.3 24.83 83 156.24 64.76 Prototype 11.67 63 50,5 30.57

Claims (2)

1. A mixture for the formation of cellulose acetate ultrafiltration membrane, consisting of cellulose diacetate in an acetone solvent and a particulate filler with a particle size of 85 μm in the following components, wt.%:
Cellulose diacetate 5,0 Acetone 62.6-68.5 Dispersed filler with a particle size of 85 microns 26.5-32.4
characterized in that as a dispersed filler contains heat treated at t = 200-400 ° C without access to oxygen, the waste of threshing millet. 2. A mixture for molding a cellulose acetate ultrafiltration membrane, consisting of cellulose diacetate in an acetone solvent and a particulate filler with a particle size of 160 μm with the following components, wt.%:
Cellulose diacetate 7.0 Acetone 67.7-78.5 Particulate filler with a particle size of 160 microns 14.5-25.3
characterized in that as a dispersed filler contains heat treated at t = 200-400 ° C without access to oxygen, the waste of threshing millet.