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METHOD OF PRESERVING DEXTRAN SOLUTION USED IN MEMBRANE FILTRATION APPLICATION

IP.com Disclosure Number: IPCOM000236054D
Publication Date: 2014-Apr-03
Document File: 3 page(s) / 76K

Publishing Venue

The IP.com Prior Art Database

Abstract

An improved method of preserving dextran solution used in membrane filtration application is proposed to maintain the integrity of the solution over extended period of time. After each usage of fresh dextran solution, the dextran is transferred into an autoclavable glass bottle and heated in a lab oven for at least two hours at 120C for complete sterilization. After the heat treatment, the solution is cooled and stored in refrigerator at around 4C with a tightly sealed cap till the next usage. The tests conducted show that the method controls bacteria growth and maintains the quality of the solution effectively through repeated usage, without the use of hazardous chemicals at low energy and processing costs. Environmental benefits accrue from greatly reduced discharge and remediation requirements for the used solution.

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METHOD OF PRESERVING DEXTRAN SOLUTION USED IN MEMBRANE FILTRATION APPLICATION

BACKGROUND

This publication relates generally to ultra-filtration membranes and more particularly to a method of preserving dextran solution used in ultra-filtration membrane characterizations tests such as molecular weight cut-off (MWCO) test. Laboratory prepared dextran solution with single size or range of different molecular weight is used to evaluate the membrane pore size and rejection capability. In some cases, a small size molecule such as sucrose is also added into the solution as a control for evaluation. Because of the nature of the contents, the solution is prone to bacterial growth during filtration tests and storage, which eventually deteriorates the solution quality and affects the accuracy of MWCO tests and needs to be discarded every five days. Traditionally, the dextran solution was claimed to be stable for years when stored in refrigerator and not used for any experimental purpose (Neame 1961). Although manufacturers claim that dextran solution can be sterilized by using autoclave or by addition of sodium hypochlorite, experimental results show that there is a change in dextran composition after autoclaving and the chemical properties of the dextran change by addition of sodium hypochlorite. In contrast to the above unsuccessful treatment methods for preserving the dextran solution for extended periods of time through repeated use, a method of preserving dextran solution by simple oven heating is proposed.

BRIEF DESCRIPTION OF DRAWINGS                                                              

Method of preserving dextran solution used in membrane filtration application is described further with reference to the following drawing in which:

Figure 1 is a flow diagram illustrating the proposed method of preserving dextran solution used in membrane test.

DETAILED DESCRIPTION

The invention proposes a new method of preserving and reusing dextran solution after MWCO test, as shown in Fig. 1. After use of fresh solution, the dextran is transferred into an autoclavable glass bottle and heated in a lab oven for at least two hours at 120°C for complete sterilization. After the heat treatment, the solution is cooled and stored in refrigerator at 4°C with a tightly sealed cap till next usage.

Fig: 1: Process flow diagram of dextran solution preservation

The quality of the treated solution was evaluat...