CN110960989A

CN110960989A - Cleaning agent for reverse osmosis membrane prepared from CMC (carboxy methyl cellulose) and preparation method of cleaning agent

Info

Publication number: CN110960989A
Application number: CN201811154792.2A
Authority: CN
Inventors: 王薇; 刘宁; 于湉
Original assignee: Tianjin Tiangongzheng Separation Membrane Inspection And Testing Technology Service Co ltd
Current assignee: Tianjin Tiangongzheng Separation Membrane Inspection And Testing Technology Service Co ltd
Priority date: 2018-09-30
Filing date: 2018-09-30
Publication date: 2020-04-07

Abstract

The invention relates to a reverse osmosis membrane cleaning agent prepared from CMC and a preparation method thereof. According to the invention, a small amount of CMC (sodium carboxymethylcellulose) is dissolved in water through the characteristics of emulsification dispersibility, solid dispersibility, corrosion resistance and physiological harmlessness of the CMC, and then the CMC is fused with a reverse osmosis membrane cleaning agent to circularly clean the reverse osmosis membrane, so that the water retention property and stability of the CMC can reduce the damage of the original reverse osmosis membrane cleaning agent to a polyamide ultrathin separation layer on the surface layer of the reverse osmosis membrane, protect a polyamide active layer with a separation effect on the surface of the reverse osmosis membrane, and prolong the service life of the reverse osmosis membrane. The reverse osmosis membrane cleaning agent disclosed by the invention is simple and easy to prepare, has no special requirements on equipment, and simultaneously plays a role in protecting a polyamide separation layer on the surface layer of the reverse osmosis membrane.

Description

Cleaning agent for reverse osmosis membrane prepared from CMC (carboxy methyl cellulose) and preparation method of cleaning agent

Technical Field

The invention belongs to the technical field of membrane element cleaning, and particularly relates to a preparation method of a reverse osmosis membrane cleaning agent.

Background

In the operation process of the reverse osmosis system, the surface of the reverse osmosis membrane can be deposited due to the existence of pollutants such as mud stains, organic matters, microorganisms and the like in raw water and the concentration of indissolvable substances in the membrane separation process, so that the pollution to the reverse osmosis membrane is formed. And the TDS value in the north is higher relatively, influences its life more, and reverse osmosis membrane cost is high, and user's replacement cost is high and troublesome. Therefore, different reverse osmosis membrane cleaning agents are prepared according to different pollutants, and the pollutants on the surface layer of the reverse osmosis membrane can be removed. However, as the usage of reverse osmosis membranes increases, users have been increasingly demanding shorter cleaning times for reverse osmosis membranes. Therefore, the method has important significance for improving the cleaning technology of the reverse osmosis membrane, prolonging the service life of the reverse osmosis membrane, reducing the water treatment cost and promoting the development of the reverse osmosis membrane technology to a wider application field.

CMC is cellulose ether, is easy to dissolve in cold and hot water, has the characteristics of solid dispersibility, difficult corrosivity, physiological harmlessness and the like, and has excellent properties of water retention, lubricity, suspension floating property and the like, so that the CMC is widely applied to the industries of food, medicine and the like. The excellent characteristics of CMC can be used for preparing efficient reverse osmosis membrane cleaning agents, but the prior art does not utilize CMC to prepare reverse osmosis membrane cleaning agents.

Disclosure of Invention

The invention provides a reverse osmosis membrane cleaning agent with high efficiency and small damage and a preparation method thereof by overcoming the defects of the prior art and utilizing the unique excellent performance of CMC.

Firstly, the invention provides a reverse osmosis membrane cleaning agent prepared from CMC and a preparation method thereof: the cleaning agent for the reverse osmosis membrane is composed of CMC, an acid and alkaline reverse osmosis membrane cleaning agent, wherein the CMC is colloidal liquid, and the reverse osmosis membrane cleaning agent is respectively prepared from citric acid, diluted hydrochloric acid or sodium hydroxide.

The above aspect may be further preferably:

the CMC glue solution is prepared from CMC powder and water, wherein the ratio of the CMC powder to the water is 1: 5.

the cleaning agent of the acidic reverse osmosis membrane can be prepared by using 1-2% of citric acid solution or 0.4% of HCL solution.

The alkaline reverse osmosis membrane alkaline cleaning agent is prepared from 0.2% of NaClO and 0.1% of NaOH.

Next, the efficient reverse osmosis membrane cleaning agent and the preparation method thereof are provided. Which comprises the following steps:

(1) dissolving CMC powder in warm water at a temperature of no more than 60 ℃, cooling to about 35 ℃ after the CMC powder is melted, then pouring the CMC powder into an acid-base preparation for cleaning a reverse osmosis membrane according to a ratio of 1:20, uniformly stirring, and standing for ten minutes;

(2) preparing CMC solution and cleaning water of reverse osmosis membrane acid-base preparation by using reverse osmosis membrane product water;

(3) circulating the cleaning solution in the pressure container for 1 hour or preset time, and setting a large flow velocity to pass through a reverse osmosis membrane product;

(4) after the cleaning is finished, the cleaning box is drained and washed, and then sensed reverse osmosis membrane product water is injected into the cleaning box for next washing.

(5) After flushing the reverse osmosis membrane, it is reinstalled and run on normal drain (about 40 minutes is recommended) until the product water is clean, no foam or detergent residue.

The above aspect may be further preferably:

the mass fraction of the CMC glue solution and the citric acid solution mixed aqueous solution is 10-11%; the mass fraction of the CMC solution and the HCl solution mixed aqueous solution is 10.2 percent; the mass fraction of the CMC solution and the mixed aqueous solution of the sodium hydrochloride and the sodium hydroxide solution is 10.15 percent.

The dissolution temperature of the CMC should be less than 60 ℃ for 6-10 hours, the dissolution temperature is further preferably 55 ℃, and the dissolution time is further preferably 8 hours.

The optimal cleaning temperature of the CMC glue solution and the mixed aqueous solution of the citric acid solution, the HCL solution, the sodium hydrochloride and the sodium hydroxide solution is 35 ℃.

The cleaning time of the reverse osmosis membrane is 1 h.

Compared with the prior art, the CMC reverse osmosis membrane cleaning agent has stable chemical performance, good water retention property, solid dispersibility, corrosion resistance and physiological harmlessness, can effectively clean pollutants of the reverse osmosis membrane, increases the hydrophilicity of the membrane, can reduce damage to the reverse osmosis membrane, prolongs the service life of the reverse osmosis membrane, reduces the cost, and does not harm drinking water.

Detailed Description

The present invention will be further described with reference to specific examples, but the present invention is not limited thereto.

Firstly, a reverse osmosis membrane cleaning agent prepared from CMC and a preparation method thereof are provided, which comprises the following steps:

(1) dissolving CMC powder in warm water at 55 ℃ in a ratio of 1:5 by using reverse osmosis membrane product water, uniformly stirring, standing for 8 hours, and dissolving into a glue solution;

(2) then mixing the solution with an acid-base solution for cleaning the reverse osmosis membrane according to the ratio of 1:20, uniformly stirring, and controlling the temperature of the mixed solution to be about 35 ℃;

(3) pouring the prepared solution into a pressure container, setting the cleaning time (recommended 1.5h, but the cleaning time can be prolonged or shortened according to actual conditions), setting a larger flow rate (recommended at 35) to allow the cleaning solution to flow through the reverse osmosis membrane in an impacting manner, after the cleaning is finished, reinstalling the reverse osmosis membrane, and normally draining to run (recommended about 40 min) until the product water is clean and has no foam or cleaning agent residues.

The using effect of the high-efficiency reverse osmosis membrane cleaning agent prepared by the method is tested by adopting the following method:

respectively adding the CMC glue solution into a citric acid solution, an HCL solution and an alkaline solution according to the ratio of 1:20, respectively pouring the mixture into a pressure container to respectively test the cleaning effect of the reverse osmosis membrane, wherein the test conditions are as follows: the preparation method comprises the steps of self-preparing 250 liters of mixed preparation, testing the temperature to be 35 ℃, soaking a reverse osmosis membrane in a solution for 0.5 hour in advance, injecting the preparation into the reverse osmosis membrane of a pure water machine, raising the head by 30 meters, opening a concentrated water discharge valve fully after the test is started, reducing the pressure as much as possible, closing a water production valve to prevent the preparation from flowing into a pure water tank, and cleaning the preparation without recycling. The testing quantity of the reverse osmosis membrane elements cleaned by each mixed preparation is at least three parts, the testing results are averaged, and the desalination rate and the water yield of the cleaned reverse osmosis membrane are recorded.

After testing, the reverse osmosis membrane cleaning time cleaned by using the reverse osmosis membrane cleaning preparation made of CMC can reach the cleaning effect within 1h, the water yield of the cleaned reverse osmosis membrane is reduced by about 7-11%, the desalination rate is reduced by about 9%, the cleaning time of other reverse osmosis membrane cleaning preparations is averagely 1.5h, the water yield of the cleaned reverse osmosis membrane is averagely reduced by 10-15%, the desalination rate is averagely reduced by 15%, and the performance of the cleaned reverse osmosis membrane is superior to that of other cleaning preparations.

Claims

1. A reverse osmosis membrane cleaning agent prepared from CMC and a preparation method thereof are characterized in that: compared with other reverse osmosis membrane cleaning agents, the CMC reverse osmosis membrane cleaning agent has the effect of quickly dissolving pollutants; the CMC reverse osmosis membrane cleaning agent can keep the water content of the reverse osmosis membrane by the water-retaining property, and reduce the influence of the reverse osmosis membrane on the performance by the environment.

2. The CMC reverse osmosis membrane cleaning agent and the preparation method thereof as claimed in claim 1, wherein the CMC glue solution is mainly composed of CMC powder and reverse osmosis membrane product water according to the proportion of 1:5, and then the CMC glue solution is added into the reverse osmosis membrane cleaning agent according to the proportion of 1:20 to form a new CMC reverse osmosis membrane cleaning agent.

3. The cleaning agent for reverse osmosis membranes made of CMC and the preparation method thereof as claimed in claim 1, characterized in that the cleaning time of reverse osmosis membranes can be reduced, the damage to the performance of reverse osmosis membranes in the cleaning process can be reduced, and the service life of reverse osmosis membranes can be prolonged.