CN101973644A - Reverse osmosis compound scale inhibitor - Google Patents

Abstract

The invention provides a reverse osmosis composite scale inhibitor, which belongs to the field of reverse osmosis water treatment. The scale inhibitor includes hydroxyethylidene diphosphonic acid, hydrolyzed polymaleic anhydride, polyacrylic acid, sulfonated styrene-maleic anhydride copolymer, and the weight percentage of each component is: hydroxyethylidene diphosphonic acid 10%～ 20%, hydrolyzed polymaleic anhydride 30%~40%, polyacrylic acid 30%~40%, sulfonated styrene-maleic anhydride copolymer 10%~20%. The antiscalant may also include a bactericide. The invention fully utilizes the synergistic effect among organic phosphine scale inhibitors, polycarboxylic acid scale inhibitors and sulfonic acid scale inhibitors, and has good scale inhibition and dispersion performance. Adding it to the reverse osmosis water inlet system can effectively reduce the pollution caused by calcium carbonate, calcium sulfate and silicate to the reverse osmosis membrane, and prolong the cleaning cycle and operating life of the reverse osmosis system.

Description

A reverse osmosis compound antiscalant

the

technical field

The invention relates to a reverse osmosis water treatment material, in particular to a reverse osmosis composite scale inhibitor capable of reducing membrane fouling.

Background technique

Reverse osmosis is a membrane separation technology that originated in the 1960s and has been widely used in water treatment. In some coastal areas where fresh water resources are scarce, reverse osmosis is used for seawater desalination to provide fresh water for people's production and life. At the same time, as a high-purity water preparation technology, reverse osmosis can meet the water requirements of semiconductor, microelectronics, electric power, chemical industry, medicine and other fields. In today's increasingly scarce water resources, reverse osmosis has also been widely used in wastewater treatment as advanced wastewater treatment technology and water resource reuse technology.

In the reverse osmosis water treatment process, membrane fouling is a key factor affecting the working efficiency and operating life of the reverse osmosis system. During the operation of the system, the bacteria, particles, colloidal particles or solute macromolecules in the feed water have physical and chemical interactions with the reverse osmosis membrane, or due to concentration polarization, the concentration of some solutes on the membrane surface exceeds its solubility and mechanical action. Adsorption and deposition on the membrane surface or in the membrane pores will cause the membrane pore size to become smaller or clogged, which will significantly reduce the membrane flux and separation characteristics, resulting in irreversible membrane fouling. Membrane fouling can be mainly divided into chemical fouling and biological fouling. The chemical pollution of the reverse osmosis system is mainly due to the deposition of carbonate scale in the membrane element and the poisoning of the membrane element due to the excessive content of Fe, Sr, and Ba in the water. Biological pollution mainly refers to the growth of microorganisms using the reverse osmosis membrane as a carrier with the help of nutrients in the concentrated water section of reverse osmosis, forming a biofilm layer on the surface of the reverse osmosis membrane, resulting in a rapid increase in the pressure difference between the inlet and outlet water of the reverse osmosis system, resulting in The water volume and desalination rate drop rapidly, and the product water is polluted at the same time. For microbial contamination, disinfection treatment is mostly used to reduce the number of microbial populations and biological activities in the influent. For inorganic scale, it can be solved by adding scale inhibitor. A good scale inhibitor can not only stabilize the inorganic scale-forming ions in the influent, but also affect the crystallization process of the inorganic scale-forming ions, reduce the force between the scale and the reverse osmosis membrane, and make it flow away with the concentrated water. At present, there are different types of reverse osmosis antiscalants in China, and there is still a certain gap in product performance compared with foreign countries. Most domestic reverse osmosis devices also use imported antiscalants.

US Patent No. 5,256,303 discloses a composite antiscalant for reverse osmosis systems, whose components include organic phosphines and acrylic acid copolymers, which can inhibit the deposition of calcium sulfate on the surface of reverse osmosis membranes. US Patent No. 5,358,640 discloses a composite scale inhibitor whose components include water-soluble organic phosphine, acrylamide polymer, caustic alkali and water. It can reduce calcium sulfate and calcium carbonate deposition pollution in reverse osmosis system. However, the disadvantages of these two scale inhibitors are that the formula contains more organic phosphine, and the reverse osmosis system must strictly control the temperature and pH value.

Contents of the invention

1. The technical problem to be solved by the invention: In view of the limited use conditions of the existing composite scale inhibitors used in reverse osmosis systems and easy to cause pollution, the present invention aims to provide a composite scale inhibitor for reverse osmosis, which can be used for reverse osmosis Osmosis process reduces membrane fouling, improves operating efficiency of reverse osmosis system, and prolongs operating life.

2. Contents of the invention

Invention principle: The reverse osmosis composite scale inhibitor composed of hydroxyethylidene diphosphonic acid, hydrolyzed polymaleic anhydride, polyacrylic acid, and sulfonated styrene-maleic anhydride copolymer is mixed in a certain proportion based on the active ingredients to make an aqueous solution , the high-performance reverse osmosis composite antiscalant provided by the present invention can be obtained. The invention fully utilizes the synergistic effect among organic phosphine scale inhibitors, polycarboxylic acid scale inhibitors and sulfonic acid scale inhibitors, and develops a high-performance composite scale inhibitor. According to different water quality conditions, the present invention can change the ratio of different components in the composite scale inhibitor.

Technical scheme of the present invention is:

A reverse osmosis composite scale inhibitor comprises hydroxyethylidene diphosphonic acid, hydrolyzed polymaleic anhydride, polyacrylic acid and sulfonated styrene-maleic anhydride copolymer. Active ingredients are calculated by weight percentage, among which the amount of hydroxyethylidene diphosphonic acid is 10% to 20%, the amount of hydrolyzed polymaleic anhydride is 30% to 40%, the amount of polyacrylic acid is 30% to 40%, and the amount of sulfonated The amount of styrene-maleic anhydride copolymer is 10% to 20%.

The further improvement of the present invention comprises one or two or three of the fungicides dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride or polyquaternium Mixed, the dosage is 1% concentration by weight of the active ingredients of the compound antiscalant (hydroxyethylidene diphosphonic acid, hydrolyzed polymaleic anhydride, polyacrylic acid and sulfonated styrene-maleic anhydride copolymer) and the net content of the fungicide %~5%.

The hydroxyethylidene diphosphonic acid used in the present invention is powdery solid or its aqueous solution, the molecular weight of hydrolyzed polymaleic anhydride is 400-2000g/mol, the molecular weight of polyacrylic acid is 2000-100000g/mol, sulfonated styrene-maleic anhydride The molecular weight of the anhydride copolymer is 1000-10000g/mol. The bactericide used in the present invention is one of dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, polyquaternium salt or a mixture of two or three thereof .

The present invention achieves a good synergistic effect by mixing different ratios of hydroxyethylidene diphosphonic acid, hydrolyzed polymaleic anhydride, polyacrylic acid and sulfonated styrene-maleic anhydride copolymer, and has a good effect on inorganic scale-forming ions and inorganic scale-forming ions. Scale has excellent chelating solubilization, lattice distortion and coagulation dispersion. 1% to 5% fungicide can prolong the shelf life of antiscalant. According to the different influent water quality of the reverse osmosis system, the dosage of the present invention is generally between 2-15 mg/L.

In order to achieve the best anti-scaling performance, the dosing point should be set before the security filter, and dosing with a metering pump to ensure that the dosage is stable and adjustable. The invention can be miscible with water in any proportion, and the dosing amount can be set according to the influent water quantity and water quality, so as to ensure the best scale inhibition effect.

3. Beneficial effects: the present invention provides a reverse osmosis composite scale inhibitor. The components are uniformly mixed according to a certain ratio and formulated into an aqueous solution to obtain the scale inhibitor provided by the present invention. The present invention can be mixed with water in any proportion, and the contents of each component are calculated as effective components (that is, the ratio of the effective components of each component to the total effective components).

The invention is used in the reverse osmosis system, which can effectively control the large-scale fouling of CaCO ₃ , CaSO ₄ , BaSO ₄ etc. on the reverse osmosis membrane, and has a certain influence on the crystallization process of inorganic salts, so that the formed inorganic scale is not easy to be deposited on the membrane surface. Deposit and flow away with concentrated water. Thereby prolonging the service life of the membrane element and greatly reducing the operating cost of the equipment.

Detailed ways:

The present invention is further illustrated in conjunction with the following examples without limiting its scope.

In the following examples, the sulfonated styrene-maleic anhydride copolymer used in the composite antiscalant formula adopts the Versa TL-3 product produced by Arco Chemical Company, hydroxyethylidene diphosphonic acid, hydrolyzed polymaleic anhydride and Polyacrylic acid adopts NC-201, NC-303, NC-301 produced by Nanjing Naco Water Treatment Technology Co., Ltd., dodecyl dimethyl benzyl ammonium chloride and tetradecyl dimethyl benzyl ammonium chloride The chemical agent from Chengdu Gracia Chemical Technology Co., Ltd. is used, and the polyquaternium is HL-505 product produced by Hubei Wuhan Xianbao Company.

Example 1

Each component is mixed and compounded according to the following proportions in terms of active ingredients:

hydroxyethylidene diphosphonic acid 20% Hydrolyzed Polymaleic Anhydride 30% Polyacrylic acid 30% Sulfonated styrene-maleic anhydride copolymer 15% Lauryl dimethyl benzyl ammonium chloride 5%

Get hydroxyethylidene diphosphonic acid aqueous solution 29.9g, hydrolyzed polymaleic anhydride aqueous solution 60.0g, polyacrylic acid aqueous solution 85.7g, sulfonated styrene-maleic anhydride copolymer aqueous solution 21.4g and dodecyl dimethyl benzyl chloride Add 11.4g of ammonium chloride into the reaction vessel, stir evenly and place at room temperature for 24 hours, the active ingredient content of the composite scale inhibitor is 48.0%. the

Example 2

Each component is mixed and compounded according to the following proportions in terms of active ingredients:

hydroxyethylidene diphosphonic acid 10% Hydrolyzed Polymaleic Anhydride 40% Polyacrylic acid 39% Sulfonated styrene-maleic anhydride copolymer 10% Lauryl dimethyl benzyl ammonium chloride 1%

According to the calculated amount, 10.0g of hydroxyethylidene diphosphonic acid powder, 80.0g of hydrolyzed polymaleic anhydride aqueous solution, 111.4g of polyacrylic acid aqueous solution, 14.2g of sulfonated styrene-maleic anhydride copolymer aqueous solution and dodecyl dimethyl Add 2.3 g of benzyl ammonium chloride into the reaction vessel, stir evenly and place at room temperature for 24 hours, the active ingredient content of the composite antiscalant is 45.9%.

Example 3

Each component is mixed and compounded according to the following ratio in terms of active ingredients:

hydroxyethylidene diphosphonic acid 15% Hydrolyzed Polymaleic Anhydride 30% Polyacrylic acid 32% Sulfonated styrene-maleic anhydride copolymer 20% Lauryl dimethyl benzyl ammonium chloride 3%

Get 22.4g of hydroxyethylidene diphosphonic acid aqueous solution, 60.0g of hydrolyzed polymaleic anhydride aqueous solution, 91.4g of polyacrylic acid aqueous solution, 28.6g of sulfonated styrene-maleic anhydride copolymer aqueous solution and dodecyl dimethyl benzyl chloride Add 6.8g of ammonium chloride into the reaction vessel and stir evenly. The active ingredient content of the composite scale inhibitor is 47.8%.

Example 4

Each component is mixed and compounded according to the following proportions in terms of active ingredients:

hydroxyethylidene diphosphonic acid 10% Hydrolyzed Polymaleic Anhydride 35% Polyacrylic acid 40% Sulfonated styrene-maleic anhydride copolymer 13% Lauryl dimethyl benzyl ammonium chloride 2%

Take 14.9g of hydroxyethylidene diphosphonic acid aqueous solution, 70.0g of hydrolyzed polymaleic anhydride aqueous solution, 114.2g of polyacrylic acid aqueous solution, 18.6 of sulfonated styrene-maleic anhydride copolymer aqueous solution and dodecyldimethylbenzyl chloride Add 4.5g of ammonium aqueous solution into the reaction vessel, stir evenly, and the active ingredient content of the composite scale inhibitor is 45.0%.

Example 5

Each component is mixed and compounded according to the following proportions in terms of active ingredients:

hydroxyethylidene diphosphonic acid 12% Hydrolyzed Polymaleic Anhydride 33% Polyacrylic acid 32% Sulfonated styrene-maleic anhydride copolymer 20% Lauryl dimethyl benzyl ammonium chloride 3%

Get hydroxyethylidene diphosphonic acid aqueous solution 17.9g, hydrolysis polymaleic anhydride aqueous solution 66.0g, polyacrylic acid aqueous solution 91.4g, sulfonated styrene-maleic anhydride copolymer aqueous solution 28.6g and lauryl dimethyl ammonium chloride Add 6.8g of the aqueous solution into the reaction vessel, stir evenly and place it at room temperature for 24 hours. The active ingredient content of the composite antiscalant is 47.4%.

Example 6

Each component is mixed and compounded according to the following proportions in terms of active ingredients:

hydroxyethylidene diphosphonic acid 12% Hydrolyzed Polymaleic Anhydride 33% Polyacrylic acid 32% Sulfonated styrene-maleic anhydride copolymer 20% tetradecyl dimethyl benzyl ammonium chloride 3%

Get 17.9g of hydroxyethylidene diphosphonic acid aqueous solution, 66.0g of hydrolyzed polymaleic anhydride aqueous solution, 91.4g of polyacrylic acid aqueous solution, 44.4g of sulfonated styrene-maleic anhydride copolymer aqueous solution and tetradecyl dimethyl benzyl chloride Add 6.8g of ammonium chloride aqueous solution into the reaction vessel, stir evenly and place at room temperature for 24 hours, the active ingredient content of the composite scale inhibitor is 44.1%.

Example 7

Each component is mixed and compounded according to the following proportions in terms of active ingredients:

hydroxyethylidene diphosphonic acid 12% Hydrolyzed Polymaleic Anhydride 33% Polyacrylic acid 32% Sulfonated styrene-maleic anhydride copolymer 20% Polyquaternium 3%

Hydroxyethylidene diphosphonic acid aqueous solution 17.9g, hydrolysis polymaleic anhydride aqueous solution 66.0g, polyacrylic acid aqueous solution 91.4g, sulfonated styrene-maleic anhydride copolymer aqueous solution 28.6g and polyquaternium salt aqueous solution 6.8g Add it into the reaction container, stir evenly and place it at room temperature for 24 hours. The active ingredient content of the composite antiscalant is 47.4%.

In order to prove the antiscaling performance of the present invention, the applicant used the composite antiscaling agent prepared by the mass ratio of Examples 1 to 7, and according to the national standard GB/T16632-2008 of the People's Republic of China "Measurement of the antiscaling performance of water treatment agent calcium carbonate deposition The anti-scaling test was carried out according to the method, and the results are shown in the following table:

Test results of static scale inhibition performance of composite scale inhibitor of the present invention

Example Effective concentration of antiscalant (mg/L) Calcium carbonate scale inhibition rate (%) Example 1 10 76.8 Example 2 15 78.2 Example 3 8 77.3 Example 4 2 70.8 Example 5 4 73.8 Example 6 6 76.3 Example 7 5 72.9

Examples The test results of scale inhibition performance show that in the evaluation method of the national standard GB/T16632-2008, the test temperature is 80°C, and the examples of the present invention exhibit excellent scale inhibition performance. However, most reverse osmosis systems operate at room temperature, and the scale inhibition effect is more obvious.

Claims (4)

1. reverse osmosis composite scale inhibitor, it is characterized in that being made up of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid, hydrolytic polymaleic anhydride, polyacrylic acid, Sulfonated Copolymer of Styrene and Maleic Anhydride, wherein the weight percent of each component is: 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid 10%～20%, hydrolytic polymaleic anhydride 30%～40%, polyacrylic acid 30%～40%, Sulfonated Copolymer of Styrene and Maleic Anhydride 10%～20%.

2. reverse osmosis composite scale inhibitor according to claim 1, it is characterized in that also comprising a kind of in dodecyl benzyl dimethyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride or the polyquaternium as sterilant or wherein two kinds or three's mixing, its weight percent content is 1%～5%.

3. reverse osmosis composite scale inhibitor according to claim 1 and 2 is characterized in that form or aqueous solution that each component exists when buying with it.

4. reverse osmosis composite scale inhibitor according to claim 1 and 2 is characterized in that reverse osmosis composite scale inhibitor usage quantity is 2～15mg/L.