Iron removal agent suitable for water treatment system and application of iron removal agent

Abstract

The invention relates to an iron removal agent suitable for a water treatment system and application of the iron removal agent. The iron removal agent is prepared from the following components in percentage by weight: 15-35% of poly dimethyl diallyl ammonium chloride, 1-5% of alkyl dimethyl benzyl ammonium halide, 0-0.5% of isothiazolinone and 60-80% of deionized water. Compared with the prior art, the invention overcomes the defects of low iron removal efficiency, large amount of generated mud and the like in the raw water conveying process of a water treatment system or the concentration process of the water system in a common iron removal technology. The iron removal agent is excellent in performance, good in stability and low in use dosage, has general applicability to iron removal in the raw water conveying or water treatment system concentration process, and has the characteristics of no phosphorus, environment friendliness and high efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of iron removers, and relates to an iron remover suitable for a water treatment system and an application thereof, and in particular to an iron remover suitable for removing low-dose divalent iron ions and trivalent iron ions in a water treatment system and an application thereof. Background Art

[0002] With the continuous large-scale development of the economy, the consumption of energy and water resources in the industrial field has increased dramatically, and the pressure on the environment has increased day by day. The government encourages enterprises to use high-tech and high-tech materials to give full play to their scientific research advantages, realize technological transformation and upgrading, encourage the implementation of new industrial water-saving processes and technologies, effectively and reasonably save water and protect water resources from pollution, improve the energy-saving and emission reduction policy system, strengthen industrial water use management, and improve the comprehensive utilization efficiency of water resources.

[0003] Industrial raw water treatment or circulating water treatment systems often have high total iron (ferrous iron, ferric iron) due to various factors, which cannot meet the requirements of circulating water quality control standards (total iron ≤ 1.0 mg / L). Excessive total iron concentration will not only cause the water color to darken and the turbidity to increase, directly affecting the water quality and polluting the water quality, but also aggravate the corrosion, deposition and microbial breeding of the pipe network system. In order to control the total iron concentration in the water body, the main way to reduce the total iron concentration is to increase the water replacement amount or be forced to reduce the concentration rate of the water treatment system. This will cause a large amount of water resources to be wasted, and at the same time bring irreversible corrosion effects to normal production and operation, especially for corrosive water bodies, the damage is more obvious. Therefore, it is necessary to conduct a systematic study on the source of iron in the water treatment system and the form of iron, and develop feasible iron removal and iron control technologies in a targeted manner to effectively reduce the total iron content of the water treatment system, ensure the long-term, stable and safe operation of the water system, and achieve the purpose of water saving and emission reduction and extending the service life of the equipment.

[0004] In industrial water treatment systems, under acidic conditions, iron mainly exists in the form of dissolved divalent iron ions. When oxygen is present in the water, divalent iron ions are easily oxidized to trivalent iron ions. Iron usually exists in the form of colloids and ions in circulating water. Colloidal iron can be stably suspended in water, but under heat or charge conditions, the stability of the colloid will be destroyed and then condensed and deposited. Under alkaline conditions, iron will form iron hydroxide precipitates. In circulating water systems, the pH is usually in the range of 6.0-9.5, and both forms of iron will exist. The main reasons for the increase in total iron concentration are long-term operation of the system, natural aging of equipment, poor water treatment corrosion control, and high total iron in make-up water. In the process of continuous concentration of the water system, the total iron concentration is further concentrated and accumulated, causing it to exceed the control index range, and causing high turbidity and aggravated corrosion in the system. To solve the problem of excessive total iron, the current common method is to adopt two methods: large-scale drainage replacement and filtration. As people's awareness of water conservation increases, a large number of drainage replacements have been strictly restricted by the total amount of downstream environmental protection emissions. Generally, they can only be carried out by bypass filtration, but some problems are encountered in the filtration process. Even the filters with better effects can only filter out some insoluble colloidal iron, and have almost no effect on soluble iron ions. The filtration efficiency is extremely low. Therefore, how to remove total iron in the water system has become a difficult problem for water treatment workers.

[0005] Domestic researchers generally use two methods, physical and chemical, to remove total iron from water treatment systems.

[0006] Patent CN103007883A provides a steel industry wastewater iron removal agent, which uses a solid waste blue ash from coal gasification as a matrix and a solid waste containing SCN produced by the HPF desulfurization process. － The granular solid iron remover is obtained by reacting the desulfurization waste liquid at a high temperature of 600-800℃ in a closed reaction. When in use, a certain amount of the iron remover is fully mixed with the iron-containing steel industry wastewater, and then allowed to stand for a certain period of time, or the iron remover is placed in an adsorption column, and then the iron-containing steel process wastewater to be treated is added to the adsorption column, so that it flows through the adsorption column and maintains a certain hydraulic retention time, so that the iron ions in the wastewater can be effectively reduced. The iron removal principle of the iron remover is mainly that the pore volume and specific surface area of ​​the semi-coke are greatly improved under the high temperature and closed reaction conditions, thereby increasing the physical adsorption performance of the iron remover. After the iron remover acts on the steel industry wastewater for 30 minutes, the iron ion concentration in the steel industry wastewater can be reduced from 12.5mg / L to 8.3mg / L, and the reduction rate can reach 33.3%. After 60 minutes of action, the iron ion concentration in the steel industry wastewater can be reduced from 12.5mg / L to 4.2mg / L, and the reduction rate can reach 65.3%.

[0007] Patent CN213727102U discloses a utility model patent for iron slag in water, which involves an iron removal device for water treatment agents, which can promote the rapid mixing of water treatment flocculants with water, so that the iron slag in the water can be quickly condensed and precipitated, greatly improving the removal efficiency of the iron slag.

[0008] Patent CN107585900A discloses a water treatment system for removing iron and manganese. The invention has good iron and manganese removal effect, compact structure, small footprint, low maintenance and operation costs, and good full-automatic control operation and long service life.

[0009] In patent CN101288845B, waste biomaterials are crushed, sieved, calcined at high temperature, and then subjected to a series of treatments to form a composite adsorption material. The adsorption material is suitable for removing fluorine, iron and manganese from drinking water, and can also be used for removing fluorine, iron and manganese from industrial wastewater.

[0010] Guo Zhenyuan et al. confirmed through engineering examples that the layered manganese sand filter has a good removal effect on iron ions in groundwater. The concentration of divalent iron ions in the inlet water dropped from 1.57 mg / L to 0.06 mg / L in the outlet water, and the removal rate reached more than 96%. The mechanism of action of manganese sand filter media in removing divalent iron ions mainly involves adsorption, separation and filtration. Chen Nan et al. used a mixed filter media of quartz sand and manganese sand to remove iron from power plant cooling water, and the effect was better than that of quartz sand filter media alone. The results showed that the mixed layer filter media with a quartz sand / manganese sand ratio of 3:7, a pH value of 6.5-8.5, and a filtration rate of 1.5 m / h had the best iron removal effect, and the iron removal rate reached 92.09%. Gao Xi et al. used activated carbon to adsorb circulating water (total iron ion content of 5.50 mg / L), added the circulating water into a beaker filled with activated carbon, and the residence time was 5 min. After the first adsorption, the total iron content in the filtrate was measured to be 2.28 mg / L. The filtrate was adsorbed by activated carbon again, and the residence time was still 5 minutes. After the second adsorption, the total iron content in the filtrate was reduced to 1.17 mg / L. At the same time, for the water quality with high total iron content in circulating water, which is difficult to control with ordinary corrosion and scale inhibitors, polyaluminium chloride was added as a flocculant before the bypass filter, and the flocculation method under high pH (alkaline conditions) was adopted to make the iron ions with excessive content in the water form floccules and filter them out, which can remove the iron oxides in the circulating water, thereby achieving the purpose of purifying the water quality. Xue Rui et al. investigated the flocculation effect of polyaluminium chloride iron (PAFC, an inorganic polymer aluminium salt flocculant) on circulating cooling water with high iron content. The results showed that PAFC can effectively reduce the iron ion content in circulating water, and the iron ion content in water is reduced from 6.49 mg / L to 0.5 mg / L. It is worth noting that while PAFC is flocculating, it will also degrade phosphorus and zinc water treatment agents in the water. At the same time, the dosage reaches 150 mg / L, and flocculent deposition is easily formed in the circulating water. Cui Yubiao and others added a diaphragm dosing pump at the inlet of the circulating cooling water post sand filter and added the iron removal agent PC1192 (imported cationic coagulant). PC1192 has a strong flocculation and sedimentation effect on suspended particles of iron ions in aqueous media. Through electrical neutralization, the negatively charged suspended particles lose their dispersion stability and react with negatively charged dissolved substances to form insoluble precipitation, thereby achieving the purpose of iron removal. The test of the iron removal effect of PC1192 showed that the iron content of circulating cooling water dropped from 5.3mg / L to 0.84mg / L, and the turbidity (NTU) dropped from 30NTU to 15NTU. The water-saving effect after iron removal was obvious. Wang Haiping and others screened a high molecular polymer QT-1 for removing soluble iron ions in industrial circulating water, and discussed its application conditions. The preliminary on-site application results of QT-1 show that under the condition of the optimal dosage of QT-1 of 30 mg / L, the total iron content in a certain air-conditioning circulating cooling water system dropped from 28 mg / L to 0.8 mg / L, meeting the requirements of industrial circulating water treatment specifications.

[0011] In summary, by setting up filter adsorption or adding agents in the side filtration system, the conversion of soluble iron into insoluble iron ions is achieved, and then under the auxiliary conditions of the filtration system, the purpose of effectively removing total iron and turbidity in the water body is achieved, which greatly reduces the discharge of water, saves water resources, and reduces the water cost of industrial enterprises. However, when the above various total iron removal methods are actually implemented, various application problems are encountered. For example, setting up filter adsorption will significantly increase the equipment investment cost, and the filter material needs to be replaced in time, which is inconvenient to operate. Whether it is adding flocculant PAFC or polymer QT-1, the dosage is large, which will significantly increase the amount of mud and there is a possibility of fouling the filtration system. In addition, the agent residue will further flocculate and precipitate in the system, resulting in local dirt deposition and the risk of corrosion under dirt. At the same time, the flocculant PAFC will also significantly degrade phosphorus and zinc agents, affecting the water treatment effect. The imported product PC1192 cationic coagulant has a low dosage (0.5 mg / L) and a good effect, but it is expensive and has a low cost performance.

[0012] In summary, the existing technology has defects such as increased production costs, inconvenient operation, possible system blockage, risk of residue and corrosion, and low cost performance of flocculants. Therefore, under the premise of ensuring the normal operation of the circulating water system, a deironing agent with excellent performance, environmental protection, high efficiency and good cost performance is designed and developed. On the one hand, it reduces the total iron content of circulating cooling water, meets the control requirements of various indicators of circulating water, ensures the long-term, efficient and safe operation of the circulating water system, achieves water saving and emission reduction, reduces comprehensive operating costs, and extends the service life of equipment; on the other hand, it responds to the requirements of sustainable development and follows the research concept of green chemistry, so that its production and use have practical significance. Summary of the invention

[0013] The purpose of the present invention is to provide an iron removal agent suitable for water treatment systems and its application in order to overcome the technical defects of the existing iron removal technology. The iron removal agent of the present invention can effectively remove the high concentration of iron ions in the raw water system and the circulating water system, and effectively control the water quality of the raw water and the circulating water.

[0014] The purpose of the present invention can be achieved by the following technical solutions:

[0015] One of the technical solutions is to provide an iron remover suitable for a water treatment system, the iron remover comprising the following components in percentage by weight:

[0016]

[0017] And the sum of each component is 100%.

[0018] Further preferred options:

[0019] Preferably, the molecular weight of the polydimethyldiallylammonium chloride is 40,000-60,000.

[0020] Preferably, the alkyl dimethyl benzyl ammonium halide is alkyl dimethyl benzyl ammonium chloride or alkyl dimethyl benzyl ammonium bromide.

[0021] More preferably, the alkyl dimethyl benzyl ammonium chloride is an alkyl dimethyl benzyl ammonium chloride having an alkyl number of twelve to eighteen.

[0022] More preferably, the alkyl dimethyl benzyl ammonium bromide is dodecyl dimethyl benzyl ammonium bromide.

[0023] Preferably, the isothiazolinone is a mixture of 5-chloro-2-methyl-4-isothiazoline-3-one and 2-methyl-4-isothiazoline-3-one; the mass ratio of 5-chloro-2-methyl-4-isothiazoline-3-one to 2-methyl-4-isothiazoline-3-one is (2.5-3.4):1.

[0024] The pharmaceutical component polydimethyldiallylammonium chloride of the present invention has a strong iron ion adsorption capacity, and has a good synergistic effect with alkyl dimethylbenzyl ammonium halide. In the water system, the pH is within the range of 6.0-9.0, and the divalent iron and trivalent iron ions mainly exist in the form of soluble colloidal ions. After the iron remover enters the water body, the strong adsorption capacity forms stable micro-flocculation with the soluble colloidal ions, and can also produce mutual adsorption with negatively charged turbidity substances, and is intercepted by the side filtration system. The flocculated colloidal ions and turbidity substances are removed with the backwashing and sewage discharge, thereby achieving the purpose of purifying water quality.

[0025] The pharmaceutical ingredient isothiazolinone of the present invention can ensure the long-term stability of the use effect of the pharmaceutical and effectively prolong the shelf life of the pharmaceutical.

[0026] The components of the agent of the present invention have good synergistic effects, forming a synergistic mode of charge adsorption-net capture-flocculation, capturing fine particles in the water body to form microflocculations, which are retained by the filter material of the filtration system, and a small amount of wastewater is discharged into the wastewater treatment system through backwashing.

[0027] The second technical solution provides an application of an iron remover suitable for a water treatment system, wherein the iron remover is used to remove iron in the water treatment system. The filling point of the iron remover in the application is selected at the total water inlet of the filtration system or the bypass filtration system of the water treatment system, and the fluid has a sufficient reaction time of 5-15 seconds from the filtration tank;

[0028] Furthermore, the water treatment system is: a raw water system or a circulating water system.

[0029] Furthermore, the use concentration of the iron remover is 1.0-5.0 mg / L, and the concentration is designed according to the total water intake. Preferably, a fixed power supply or a mobile power supply is used for continuous injection by a metering pump, and the output voltage is ~220V, and the outlet pressure of the metering pump is greater than the pipe network pressure; generally speaking, the iron remover is used in the raw water or circulating water system at a concentration of about twice the total iron concentration of the system for metering, that is, the agent concentration: iron ion ratio is 2:1, combined with the total water intake, the continuous injection dosage is calculated, and the changes in the total iron concentration of the import and export are detected. According to the iron removal effect, the optimal dosage is debugged and confirmed.

[0030] Furthermore, the pH value of the iron remover in a 1% by weight aqueous solution is 5.0-7.0.

[0031] Compared with the prior art, the iron removal agent and its application provided by the present invention have at least the following advantages:

[0032] (1) The iron removal effect of the iron removal agent technology of the present invention is better than that of the imported cationic flocculant PC1192 product used on the market, and the dosage used is equivalent. It is continuously injected in dosage according to the total water volume of the side filtration or filtration system through a simple metering pump, which can quickly and effectively capture iron ions and turbidity substances, and form micro-floc reaction products with total iron colloidal ions in a very short time, so that the iron ions in the water body are removed, effectively solving the problem of large-scale water quality replacement caused by high iron ions, greatly reducing the system wastewater discharge, and then reducing the amount of make-up water, achieving the purpose of water saving and emission reduction, and realizing good economic benefits, environmental benefits and social benefits for industrial enterprises.

[0033] (2) The pharmaceutical composition of the present invention does not contain phosphorus and the dosage is very low, thus avoiding the eutrophication problem that may be caused by the discharge of water bodies, and generating very little sewage and wastewater, which is beneficial to water conservation, emission reduction and environmental protection.

[0034] (3) In addition to the preferred excellent performance of polydimethyldiallyl ammonium chloride, the alkyl dimethylbenzyl ammonium halide in the iron remover formula of the present invention has a good synergistic effect with it, which can promote the iron remover to form microflocculation with total iron colloid ions and adsorb turbidity substances. At the same time, the isothiazolinone in the formula components can ensure that the iron remover remains stable for a long time during transportation and storage, and has a certain inhibitory effect on microorganisms.

[0035] (4) The present invention is applicable to raw water or circulating water systems, and can significantly reduce wastewater discharge, which is beneficial to water conservation and emission reduction.

[0036] (5) The present invention has good stability and good compatibility with common fungicides, such as chlorine-type and bromine-type oxidizing fungicides and organic sulfur-type, quaternary ammonium salt and other non-oxidizing fungicides.

[0037] (6) The pharmaceutical composition of the present invention has almost no adsorption effect on substances such as calcium ions, phosphate ions, zinc ions, etc. that exist in the form of ions in water.

[0038] (7) The agent of the present invention is used at an extremely low concentration, and the micro-flocculation is formed due to the electrostatic repulsion and complementary flocculation. After being trapped in the filter, it can be removed by normal backwashing, and there is no risk of fouling and clogging the filtration system.

[0039] (8) The drug formulation of the present invention can achieve stable and continuous injection through a simple metering pump or a simple metering pump equipped with a mobile power supply according to the change of the total water inlet of the filter. It is easy to operate, uses a low dosage, and has no obvious drug residue problem. It solves the problems existing in general iron removal technology and iron removal agents, ensures the application effect of water treatment technology, and provides technical guarantee for convenient and efficient water quality management.

[0040] (9) The raw materials of the pharmaceutical formula of the present invention are widely available, the dosage is low, the iron removal effect reaches 80% or more, and the price is moderate. Compared with other iron removal agent technologies on the market, it has a good cost-effectiveness and can reduce the comprehensive pharmaceutical treatment cost of the circulating water system.

[0041] (10) The pharmaceutical formulation of the present invention has a wide range of uses, and is particularly suitable for raw water pretreatment systems containing low concentrations of iron ions and industrial circulating cooling water systems with long-term high iron ion concentrations. It can effectively remove the existing iron ions and turbidity substances in the water system, and avoid the problems of iron bacteria breeding, increased turbidity, and increased corrosion rate caused by high iron ions. It can be widely used in circulating cooling water systems and raw water pretreatment systems in various industries such as petrochemicals, fertilizers, electric power, and coal chemical industries. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific embodiments. It should be noted that the following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, several variations and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0043] All raw materials of the present invention are not particularly limited in their sources, and can be purchased on the market or prepared according to conventional methods well known to those skilled in the art. The determination of water quality indicators (such as pH, turbidity, conductivity, calcium hardness, total alkalinity, chloride ion, total iron, etc.) in the embodiments is determined according to national standard methods, and the relevant methods are well known to those skilled in the art and will not be described in detail here.

[0044] Embodiment 1:

[0045] For the circulating water system of a petrochemical company in Dongying, Shandong, a deironing agent suitable for the water treatment system is provided. The deironing agent is composed of the following components in percentage by weight:

[0046] Polydimethyldiallylammonium chloride: 20.0%;

[0047] Dodecyl dimethyl benzyl ammonium chloride: 1.0%;

[0048] Deionized water: 79%.

[0049] Circulating water system: circulating water volume 15000m 3 / h, water capacity 6000m 3 . The make-up water is mainly purified water from the Yellow River, with a small amount of underground well water. The iron ion content in the make-up water is relatively high, with an average iron ion of 0.25 mg / L and above. The concentration ratio of the circulating water system is required to be ≥4.0 times. After the iron ions accumulate, they are greater than 1.0 mg / L, which exceeds the index control requirement (the standard requires total iron ≤1.0 mg / L). In addition, during the actual operation, due to the switching of local equipment in the system or slight corrosion of the equipment material of the system itself, the iron ions in the circulating water system exceed the standard. In order to solve the problem of excessive iron ions, a slight modification is made to the main water inlet network of the bypass filtration system, and an iron removal agent filling port is set before the valve of the main water inlet pipeline of the bypass filtration system. The partial resistance of the valve promotes the formation of a turbulent state in the water body. The iron removal agent enters the water body and quickly mixes with the iron colloid ions and turbidity substances in the incoming water, and then enters the filter tank. The iron removal agent dosing box is set indoors, and a diaphragm pump is used to pump the iron ions according to the total water inlet volume of 500m 3 / h, about 1.5L / h of iron removal agent stock solution is added every hour, and the metered concentration is about 3.0mg / L.

[0050] System water quality at time 0:

[0051] Make-up water: pH 8.20, turbidity 0.78 NTU, conductivity 859 us / cm, calcium hardness 158.73 mg / L, total alkalinity 140.53 mg / L, chloride ion 94.57 mg / L, total iron 0.34 mg / L.

[0052] About 24 hours after the addition of the iron remover, the iron ion concentration in the circulating water system dropped rapidly from 1.41 mg / L (the value measured after the total iron of 0.34 mg / L was concentrated to 4.0 times) to 0.28 mg / L, and the total iron quickly reached the index control requirements. The cumulative iron ion removal effect of the iron remover reached 80% or more, and its iron ion removal effect was very obvious.

[0053] Example 2

[0054] For the chemical circulating water system of a petrochemical company in Zhoushan, Zhejiang, a deironing agent suitable for the water treatment system is provided. The deironing agent is composed of the following components in percentage by weight:

[0055] Polydimethyldiallylammonium chloride: 30.0%;

[0056] Dodecyl dimethyl benzyl ammonium chloride: 1.0%;

[0057] Isothiazolinone: 0.5%; wherein the mass ratio of 5-chloro-2-methyl-4-isothiazolin-3-one to 2-methyl-4-isothiazolin-3-one is (2.5-3.4):1, which can fluctuate up and down and is within an acceptable error range;

[0058] Deionized water: 68.5%.

[0059] Ethylene unit circulating water system, circulating water volume 90000m 3 / h, water capacity 50000m 3 The replenishment water of the circulating water system is a mixture of seawater desalination water and double membrane recycled water, and its water quality is as follows:

[0060] Water quality at time 0:

[0061] Desalination water quality indicators:

[0062] pH 6.0-8.5, turbidity <1.0NTU, conductivity <100us / cm, calcium hardness 0.6mg / L, sulfate 0.4mg / L, total alkalinity <50mg / L, chloride ion <25mg / L, total iron <0.3mg / L.

[0063] Double membrane reuse water quality indicators:

[0064] pH 6.5-9.0, turbidity ≤0.3NTU, total dissolved solids <100mg / L, calcium hardness 0.6mg / L, sulfate 0.4mg / L, total alkalinity <50mg / L, chloride ion <25mg / L, total iron <0.3mg / L.

[0065] Desalinated water and recycled water have extremely low hardness and alkalinity, and the make-up water is weakly acidic, which has a strong tendency to corrode metal pipe equipment. During the delivery of make-up water, since the make-up water delivery pipeline has not been treated with anti-corrosion, the iron ion content of the make-up water is relatively high when it enters the circulating water system, usually reaching 0.1-0.2 mg / L. After entering the circulating water system, the concentration ratio is required to reach 10-15 times. Excessive iron ions will inevitably exceed the control index requirements (iron ions ≤ 1.0 mg / L), which restricts the improvement of the concentration ratio. In order to remove the key factors that restrict the improvement of the concentration ratio, it is confirmed to set the iron removal agent filling port from the total water inlet of the quartz sand filtration system. Through debugging, the iron removal agent is added at a concentration of 3.5 mg / L, and the iron ions of the system are stably controlled to be <0.3 mg / L and below, maintaining the stable operation of the system water quality, greatly reducing the low concentration ratio caused by high iron ions, reducing a large amount of discharged water, achieving good water-saving and emission reduction effects, and greatly reducing the water production and water production costs of desalinated seawater.

[0066] Example 3

[0067] A deironing agent suitable for water treatment system of a refining and chemical circulating water system of a Sinopec Guangdong refining and chemical company, the deironing agent is composed of the following components in percentage by weight:

[0068] Polydimethyldiallylammonium chloride: 35.0%;

[0069] Dodecyl dimethyl benzyl ammonium chloride: 1.0%;

[0070] Isothiazolinone: 0.5%; wherein the mass ratio of 5-chloro-2-methyl-4-isothiazolin-3-one to 2-methyl-4-isothiazolin-3-one is (2.5-3.4):1, which can fluctuate up and down and is within an acceptable error range;

[0071] Deionized water: 63.5%.

[0072] Refinery circulating water system circulating water volume 35000m 3 / h, water capacity 27000m 3 , bypass water volume is about 1150m 3 / h, biochemical reuse water accounts for 50% or more of the total replenishment water, and the relevant water quality is as follows:

[0073] Water quality at time 0:

[0074] Recycled water: pH 8.09, turbidity 9.99NTU, conductivity 716us / cm, calcium hardness 123.4mg / L, total alkalinity 115.1mg / L, chloride ion 53.6mg / L, total iron 0.46mg / L, ammonia nitrogen 0.2mg / L.

[0075] Municipal water supply: pH 7.48, turbidity 0.32NTU, conductivity 152us / cm, calcium hardness 30.81mg / L, total alkalinity 40.04mg / L, chloride ion 42.86mg / L, total iron 0.11mg / L.

[0076] The circulating water system reuses a large amount of recycled water, and the quality of the recycled water is poor. The iron ion concentration is often high, usually reaching 0.2-0.4 mg / L. After entering the circulating water system and reaching the concentration ratio (≥4.0 times), the total iron ion exceeds 1.5 mg / L, affecting the normal operation and management of water quality. In order to solve the problem of excessive total iron, combined with the actual working conditions, an online start is set in front of the total water inlet valve of the side filter, and a simple dosing device is made with a mobile power supply and a metering pump. The iron removal agent is continuously added according to the total water inlet, and the dosing concentration is stably controlled at 3.0-4.0 mg / L. The side filter effluent is taken for iron ion analysis, and the effluent iron ion is <0.2 mg / L, and the total iron removal effect reaches 85% or more. After two days of continuous filling, the total iron ion gradually dropped to below 0.5 mg / L, the circulating water quality was clear and transparent, and the turbidity was significantly reduced. While the water quality was restored, the purpose of water saving and emission reduction was achieved.

[0077] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An iron removal agent suitable for a water treatment system, characterized in that: The deironing agent is composed of the following components in percentage by weight: And the sum of each component is 100%.

2. The iron removal agent suitable for a water treatment system according to claim 1, characterized in that: The molecular weight of the polydimethyldiallylammonium chloride is 40,000-60,000.

3. The iron removal agent suitable for a water treatment system according to claim 1, characterized in that: The alkyl dimethyl benzyl ammonium halide is alkyl dimethyl benzyl ammonium chloride or alkyl dimethyl benzyl ammonium bromide.

4. The iron removal agent suitable for a water treatment system according to claim 3, characterized in that: The alkyl dimethyl benzyl ammonium chloride is an alkyl dimethyl benzyl ammonium chloride having an alkyl number of twelve to eighteen.

5. The iron removal agent suitable for a water treatment system according to claim 3, characterized in that: The alkyl dimethyl benzyl ammonium bromide is dodecyl dimethyl benzyl ammonium bromide.

6. The iron removal agent suitable for a water treatment system according to claim 1, characterized in that: The isothiazolinone is a mixture of 5-chloro-2-methyl-4-isothiazoline-3-one and 2-methyl-4-isothiazoline-3-one; the mass ratio of the 5-chloro-2-methyl-4-isothiazoline-3-one and 2-methyl-4-isothiazoline-3-one is (2.5-3.4):

1.

7. The use of an iron removal agent suitable for a water treatment system as claimed in claim 1, characterized in that: The iron remover is used to remove iron in a water treatment system.

8. The use of an iron removal agent suitable for a water treatment system according to claim 7, characterized in that: The water treatment system is: a raw water system or a circulating water system.

9. The use of an iron removal agent suitable for a water treatment system according to claim 7, characterized in that: The filling point of the iron remover is selected at the total water inlet of the filtration system or the bypass filtration system of the water treatment system.

10. The use of an iron removal agent suitable for a water treatment system according to claim 7, characterized in that: The use concentration of the iron remover is 1.0-5.0 mg / L.

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