Layer by layer self-assembly compound nanofiltration membrane based on natural cellulose polyelectrolyte and preparation method

A natural cellulose and composite nanofiltration membrane technology, applied in the field of membrane separation, can solve the problems of undiscovered natural cellulose polyelectrolyte composite nanofiltration membrane, and achieve good anti-pollution performance, cost reduction, and controllable membrane layer

Active Publication Date: 2014-02-05
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Based on the above literature review, it can be known that there is no relevant report on the preparation of natural cellu

Method used

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  • Layer by layer self-assembly compound nanofiltration membrane based on natural cellulose polyelectrolyte and preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Pretreat the base membrane to make its surface negatively charged: use polyacrylonitrile ultrafiltration membrane as the base membrane, immerse it in a 2.0 mol / L sodium hydroxide solution, and treat it at 30°C for 90 minutes. Take it out and rinse it repeatedly with deionized water to a pH of 7.

[0023] (2) Preparation of polyelectrolyte solution: Polydimethyldiallylammonium chloride (PDDA) is selected and dissolved in deionized water to prepare a cationic polyelectrolyte solution with a concentration of 7.0 g / L. Sodium carboxymethyl cellulose (CMC-Na) is dissolved in deionized water to prepare an anionic cellulose polyelectrolyte solution with a concentration of 1.0 g / L. Among them, when preparing an anionic polyelectrolyte solution, sodium carboxymethyl cellulose (CMC-Na) should be slowly added under stirring to prevent it from agglomerating and preventing dissolution. After stirring evenly, let it stand for 24 hours to defoam and make it fully dissolved.

[0024] (...

Embodiment 2

[0028] (1) Pretreat the base membrane to make its surface negatively charged: use polyacrylonitrile ultrafiltration membrane as the base membrane, immerse it in a 2.0 mol / L sodium hydroxide solution, and treat it at 30°C for 90 minutes. Take it out and rinse it repeatedly with deionized water to a pH of 7.

[0029] (2) Preparation of polyelectrolyte solution: Polydimethyldiallylammonium chloride (PDDA) is selected and dissolved in deionized water to prepare a cationic polyelectrolyte solution with a concentration of 5.0 g / L. Sodium carboxymethyl cellulose (CMC-Na) is dissolved in deionized water to prepare an anionic cellulose polyelectrolyte solution with a concentration of 2.0 g / L. Among them, when preparing an anionic polyelectrolyte solution, sodium carboxymethyl cellulose (CMC-Na) should be slowly added under stirring to prevent it from agglomerating and preventing dissolution. After stirring evenly, let it stand for 24 hours to defoam and make it fully dissolved.

[0030] (...

Embodiment 3

[0034] (1) Pretreat the base membrane to make its surface negatively charged: use polyacrylonitrile ultrafiltration membrane as the base membrane, immerse it in a 2.0 mol / L sodium hydroxide solution, and treat it at 30°C for 60 minutes. Take it out and rinse it repeatedly with deionized water to a pH of 7.

[0035] (2) Preparation of polyelectrolyte solution: Polydimethyldiallylammonium chloride (PDDA) is selected and dissolved in deionized water to prepare a cationic polyelectrolyte solution with a concentration of 5.0 g / L. Sodium carboxymethyl cellulose (CMC-Na) is dissolved in deionized water to prepare an anionic cellulose polyelectrolyte solution with a concentration of 2.0 g / L. Among them, when preparing an anionic polyelectrolyte solution, sodium carboxymethyl cellulose (CMC-Na) should be slowly added under stirring to prevent it from agglomerating and preventing dissolution. After stirring uniformly, let it stand for 18h to degas to make it dissolve fully.

[0036] (3) Th...

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Abstract

The invention discloses a layer by layer self-assembly compound nanofiltration membrane based on natural cellulose polyelectrolyte and a preparation method, belonging to the technical field of membrane separation. The preparation method comprises the following steps: firstly, adopting an ultrafiltration membrane as a base membrane for preparing a compound nanofiltration membrane, carrying out chemical modification on the surface of the base membrane to ensure that the surface of the base membrane has a charge property so as to generate static reaction with a polyelectrolyte; and secondly, through alternating depositing anionic and cationic polyelectrolytes, preparing the compound nanofiltration membrane through a layer by layer self-assembly method. According to the preparation method, the adopted cationic polyelectrolyte is a natural cellulose polyelectrolyte; compared with a currently used synthetic polyelectrolyte, the natural cellulose polyelectrolyte is lower in cost, and is an environmental-friendly resource; and the prepared compound nanofiltration membrane containing natural cellulose is good in hydrophilcity and charge performance so that the surface of the membrane is good in pollution resistance; and the compound nanofiltration membrane has a good retaining property for dye molecules such as divalent metal ions such as Ni<2+>, xylenol orange sodium salt, and rhodamine B.

Description

Technical field [0001] The invention belongs to the technical field of membrane separation, and relates to a natural cellulose polyelectrolyte composite nanofiltration membrane and a preparation method. Background technique [0002] Nanofiltration (NF) membrane is a pressure-driven membrane between ultrafiltration (UF) membrane and reverse osmosis (RO) membrane. It was developed in the early 1980s. Because of its special charging performance and membrane pore size distribution, nanofiltration membranes have demonstrated their unique advantages in the separation of ions with different valences and the separation of small molecular organics. [0003] Currently, composite methods are commonly used to prepare composite nanofiltration membranes with large flux and high retention performance. Specific preparation methods mainly include coating method (such as the patent of publication number CN101879416A), interfacial polymerization method (such as the patent of publication number CN102...

Claims

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Application Information

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IPC IPC(8): B01D69/12B01D71/12B01D67/00
Inventor 秦振平杜子昂郭红霞李叶单玲珑耿常乐
Owner BEIJING UNIV OF TECH
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