Method for improving polyamide reverse osmosis membrane performance through surface modification

A reverse osmosis membrane and surface modification technology, applied in reverse osmosis, semi-permeable membrane separation, chemical instruments and methods, etc., can solve the problems of membrane flux reduction, achieve membrane flux improvement, easy implementation, and reduce application operation cost effect

Active Publication Date: 2016-07-20
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The reported anti-fouling modification methods of polyamide reverse osmosis membranes will reduce the membrane flux while improving the anti-fouling performance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Prepare 1g / L sodium lignosulfonate solution, under the conditions of operating pressure of 0.6MPa, membrane surface flow rate of 3m / s, and temperature of 25 degrees Celsius, cross-flow filtration of 5 lignin solutions with a flat polyamide reverse osmosis membrane hours, and then rinsed the residual lignin solution on the membrane surface twice with pure water under the conditions of no pressure and a membrane surface flow rate of 4 m / s to obtain a modified reverse osmosis membrane. The tested membrane flux increased by 7%, and the rejection rate of sodium chloride was 98.06%.

Embodiment 2

[0028] Prepare 0.5g / L alkaline lignin solution, under the conditions of operating pressure of 2MPa, membrane surface flow rate of 1m / s, and temperature of 30 degrees Celsius, cross-flow filtration of lignin solution 3 with a roll-type polyamide reverse osmosis membrane hours, and then rinsed the residual lignin solution on the membrane surface three times with pure water under the conditions of no pressure and a flow rate of 3 m / s on the membrane surface to obtain a modified reverse osmosis membrane. The tested membrane flux increased by 24%, and the rejection rate of inorganic salt sodium chloride was 98.5%.

Embodiment 3

[0030] Prepare 2g / L alkaline lignin solution, under the conditions of operating pressure of 1MPa, membrane surface flow rate of 0.5m / s, and temperature of 45 degrees Celsius, cross-flow filter the lignin solution with a flat polyamide reverse osmosis membrane for 1 hour , and then rinse the residual lignin solution on the membrane surface for 4 times with pure water under the conditions of no pressure and a membrane surface flow rate of 1 m / s to obtain a modified reverse osmosis membrane. The tested membrane flux increased by 12%, and the rejection rate of inorganic salt sodium chloride was 98.8%.

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Abstract

The invention relates to a method for improving polyamide reverse osmosis membrane performance through surface modification. The method comprises the specific steps that a lignin solution is prepared at first; then, the prepared lignin solution is filtered through a polyamide reverse osmosis membrane on the conditions of the certain pressure, flow speed and temperature; finally, the lignin solution in a device is discharged, and pure water is used for flushing the membrane device on the conditions of zero pressure and high flow speed to obtain the modified reverse osmosis membrane. According to the modified reverse osmosis membrane obtained through the method, the membrane surface roughness is improved, the load electric property is enhanced, the membrane osmosis performance is remarkably improved, the membrane anti-pollution capacity is improved, and the operation cost of the reverse osmosis membrane can be lowered.

Description

technical field [0001] The invention relates to a method for surface modification to improve the performance of a polyamide reverse osmosis membrane. It belongs to the method of surface treatment of membrane material. Background technique [0002] A reverse osmosis membrane is a semi-permeable membrane that uses pressure as a driving force to trap solutes in a solution. Compared with the evaporation separation process, reverse osmosis has the advantages of low cost, simple operation process, high removal efficiency and environmental friendliness, and is widely used in many fields such as desalination of seawater and brackish water, wastewater treatment, concentration and separation. [0003] At present, commercial reverse osmosis membranes are mainly made of aromatic polyamide materials. How to improve the membrane permeability and anti-fouling performance is a hot spot in reverse osmosis membrane research. The most important method is to modify the membrane surface. The mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/56B01D69/06B01D67/00B01D61/02
CPCB01D61/025B01D67/0088B01D69/06B01D71/56
Inventor 邢卫红吴雅萍陈朋利汪勇李卫星
Owner NANJING UNIV OF TECH
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