Chemical product comprising an anionic surfactant, chelant, and enzyme, and process for cleaning nanofiltration and reverse osmosis membranes

Abstract

The present invention relates to a chemical product and process for cleaning nanofiltration and reverse osmosis membranes, based on enzymatic action aiming to remove biofouling and inorganic scale quickly. The product mentioned in present invention also proposes elimination of the neutralization step of the chemical product used, given that the enzymatic action allows an adequate pH for disposal to be maintained, which fact increases the speed and efficiency of the process.

Claims

1. A chemical product for cleaning nanofiltration and reverse osmosis membranes consisting of: A) from 0.1 to 10% of a surfactant agent selected from the group consisting of dodecylbenzene sodium sulfonate, sodium lauryl sulfate, sodium lauryl ether sulfate, and sodium stearate; B) a chelating agent selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), sodium or potassium salt thereof, and diethylenetriaminepentaacetic acid (DTPA), or sodium or potassium salt thereof; C) an enzymatic agent selected from the group consisting of an amylase, a cellulase, a xylanase, a lipase, and a mixture of these enzymes; and D) a buffering (pH regulating) solution.

2. The product of claim 1, wherein the concentration of the chelating agent is between 0.1 and 10%.

3. The product of claim 1, wherein the total concentration of the enzymatic agents in said product is between 0.1 and 5%.

4. The product of claim 1, wherein the buffering solution (pH-regulating solution) maintains and/or adjusts the pH between 7 and 9.

5. A process for cleaning nanofiltration and reverse osmosis membranes, wherein the process uses a product as defined in claim 1.

6. The process of claim 5, wherein the process performs cleaning of the membranes through performance of circulation and wetting cycles.

7. The process of claim 5, wherein each wetting step lasts between 1 and 4 hours.

8. The process of claim 6, wherein at the end of the circulation and wetting cycles, the solution is disposed.

9. The process of claim 8, wherein after finalizing the cleaning the process includes rinsing with industrial water directly for disposal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) This invention will be described in greater detail below, referencing the attached FIGURE, which clearly and unrestrictedly of the inventive scope, provide examples of its realization. The designs show:

(2) FIG. 1 contains a simplified diagram of the process for cleaning nanofiltration and reverse osmosis membranes in accordance with this invention, in which the following are shown:

(3) 1. Bank of first-stage membranes 2. Bank of second-stage membranes 3. Filter 4. Circulation pump 5. Cleaning solution tank PPermeate RWaste DDrain V1, V2, V3, V4, V5, V6Valves

DETAILED DESCRIPTION OF THE INVENTION

(4) In the principal aspect of this invention, a chemical product is described for cleaning nanofiltration and reverse osmosis membranes, using a surfactant agent, a chelating agent, an enzymatic agent, and a buffering solution (or pH regulator).

(5) In this principal aspect, note that the surfactant agent may be selected from among sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium lauryl ether sulfate, or sodium stearate, in which the surfactant agent is at a concentration of 0.1 to 10%.

(6) Also in relation to the same principal aspect, the chelating agent is ethylenediaminetetraacetic acid (EDTA), its sodic or potassic salt, or diethylenetriaminepentaacetic acid (DTPA), or its sodic or potassic salt.

(7) In the same principal aspect, it is also noted that the concentration of the chelating agent is between 0.1 and 10%.

(8) Also on the mentioned principal aspect, the enzymes used are amylases, cellulases, xylanases, lipases, or a mixture of these enzymes, with a total concentration between 0.1 to 5%.

(9) A buffering solution is used (or a pH-regulating solution), which maintains and/or adjusts the pH of the solution between 7 and 9.

(10) In a second aspect of this invention, it is noted that the nanofiltration and reverse osmosis membrane cleaning process uses the product defined above, which is comprised of a surfactant agent, a chelating agent, an enzymatic agent, and a buffering solution.

(11) In this second aspect, it is noted that the process refers to membrane cleaning through performance of circulation and wetting cycles.

(12) Also in this second aspect, it is noted that each wetting step lasts from 1 to 4 hours.

(13) In the second aspect of this invention, it must also be noted that at the end of the circulation and wetting cycles the solution is discarded, eliminating the need for the neutralization process.

(14) Thus this invention has technical advantages in the operation of sulfate-removal systems, which involves periodic stoppages for cleaning and removal of biofouling, and inorganic incrustations, as it eliminates the need for neutralization of the cleaning solution before disposal.

(15) Thus, the nanofiltration and reverse osmosis membrane-cleaning system based on enzymatic action described in this document has an effective cleaning solution, which dispenses with the use of more aggressive chemical products, which may be discarded directly without the need to neutralize the solution.

(16) It should be noted that although this invention has been described in relation to the attached drawing, it may be modified and adapted by experts versed in the matter, depending on the specific situation, but remaining within the inventive scope defined herein.