SU1432070A1 - Composition for forming ultrafiltration membranes - Google Patents

Abstract

The invention relates to chemical technology, in particular to the preparation of cellulose-based semipermeable membranes for ultrafiltration, and makes it possible to increase the separating ability of membranes up to 58% due to the fact that a solution containing, in wt.%, Is used for forming: cellulose 3.5- 7.2; carboxymethylcellulose 0.35-3.5; solvent up to 100%. As a solvent, the solution contains a mixture of dimethylformamide and nitrogen (IV) at a ratio of 4-5: 1. 1 hp ff, 2 tab. one

Description

four

SAE

Is9

This invention relates to chemical technology, in particular to the preparation of cellulose-based semi-permeable ultrafiltration membranes.

The aim of the invention is to increase the separation capacity of membranes.

Example 1.66% w / w% sulfate cellulose with SP 600 and 0.35% w / w carboxymethylcellulose (CMP) are dissolved under continuous stirring in 93% by weight of a mixture of dimethylformamide (daFA) and nitrogen (IV) oxide at a ratio of 4.3 :one,

The solution is filtered, air dried and applied using a slotted die with a fixed gap on the substrate, held for 2 minutes

In the spirit of 50–70% relative humidity and immersed in water, the Forming membrane is washed in water from residual solvent.

Example 2-6, Similarly, receive the membrane by processing the composition of the following composition, wt,%: cellulose 6.3, CMC 0.7, solvent 93; cellulose 4.9, CMC 2.1, solvent 93; cellulose 3.5, CMC 3.5, solvent 93, In all cases, the solvent is a mixture of DMF and nitrogen oxide (TV) with a ratio of 4.3: 1,

The characteristics of the obtained membranes are given in table.

obtained when going beyond the limits of the proposed formulations are given for comparison,

The characteristics of the membranes are carried out on an Ж02-200 membrane filter at 0.1 MPa and, 0.1% aqueous solutions of egg albumin and chymotrypsin (M 2400D) are used as capillaries. The productivity (G) and the degree of separation of dissolved substances are determined. (., where H and R ' are membrane retention factors with respect to egg albumin and chymotrypsin, respectively.

Example 7. 7.2 masl of cellulose, 0.8 wt.% CMC and 92 wt.% Mixture

Table 1

dimethylformamide and nitric oxide (IV), the ratio of the last 4: is stirred until a clear, viscous solution is formed. The preparation of the membrane is carried out according to Example I. The productivity of the obtained membrane is 30.6% separation of solutes 28%,

In the example, a composition of the following composition is prepared, wt.%: Cellulose 4.0; CMC 1, 0; a mixture of DMF - nitric oxide (rv) 95, the ratio of DMF and nitric oxide (IV) is 5: 1, the resulting solution is filtered, deaerated, applied to the substrate, incubated for 1.5 minutes in air with a relative humidity of 76% and precipitated in water The formed membrane is washed in water to a constant pH of the washing liquid.

The membrane capacity is 65, the degree of separation of solutes is 38%,

PRI me R 9 (control), Get a solution of the following composition, wt,%: cellulose 73; nitric oxide (IV) 8; polyvinyl chloride (PVC) 9; DMF 96; polyacrylonitrile (PAN) 11.5

Based on these relationships, the composition of the solution for the preparation of membranes corresponds to the following, wt%: cellulose 3.9; PVC 0.48; PAN 0.62; nitric oxide (IV) 7.3; LMPA 87.7.

The solution is prepared by mixing two separately prepared solutions.

To prepare a first solution of 3.9 hours, sulphate pulp with SP 820, pour a mixture of 7.3 hours, nitric oxide (IV) and 77.7 hours of LMFA beforehand, and mix until a clear, viscous solution is obtained. For the preparation of a second solution of 0.48 h, PVC and 0.62 h, PAN was poured over 10 hours. DMF and dissolved 30 min at 50 ° C. Then the solutions are drained and stirred for 1 ~ 3 h,

The membrane is formed by nanoorning a thin layer of solution onto a polished surface, followed by immersion in a precipitation bath (water at). The formed membrane is washed from the residual solvent and its filtration characteristics are determined.

The data obtained are given in Table 2.

Table 2.

Suggested examples

Claims (1)

Invention Formula 1, A solution for forming ultrafiltration membranes containing cellulose, a solvent and a modifying additive, characterized in that, in order to increase the separating ability of membranes, the solution contains carboxymethylcellulose in the following ratio of components, wt.%: Cellulose Carboxymethyl- Cellulose Solvent 2, The solution according to claim 1, i, u and so that 3.5-7.2 0.35-3.50 The rest is different as the solvent; it contains a mixture of dimethylformamide and nitric oxide (IV) with a ratio of 45 components (4-5): 1,