CN113603187A

CN113603187A - High-hardness underground water physicochemical hardness removal method based on composite modified macroporous resin

Info

Publication number: CN113603187A
Application number: CN202110941868.1A
Authority: CN
Inventors: 吴黎明; 乐恺宸; 徐敬生; 许辉学; 吕路
Original assignee: Enire Jiangsu Environmental Development Co ltd
Current assignee: Enire Jiangsu Environmental Development Co ltd
Priority date: 2021-08-17
Filing date: 2021-08-17
Publication date: 2021-11-05
Anticipated expiration: 2041-08-17
Also published as: CN113603187B

Abstract

The invention relates to the technical field of mineral water hardness removal, in particular to a high-hardness underground water physicochemical hardness removal method based on composite modified macroporous resin; on the basis of greatly reducing calcium and magnesium ions in RO concentrated water by adopting composite modified macroporous resin with orderly arranged three-dimensional apertures, the process flow of raw water → a pre-settling regulating tank → a flocculation sedimentation tank → a high-density sedimentation tank → a valveless filter tank → an ultrafiltration system → a reverse osmosis system → a hardness removal system → an electrodialysis system can reduce the hardness of the raw water from 300mg/L to 1.5mg/L, namely the hardness of the calcium ions from 120mg/L to 0.5mg/L, can meet the requirement that the calcium ions in the water fed by electrodialysis are less than 1.84mg/L, and effectively avoids the scaling risk formed by calcium sulfate in the electrodialysis system.

Description

High-hardness underground water physicochemical hardness removal method based on composite modified macroporous resin

Technical Field

The invention relates to the technical field of mineral water hardness removal, in particular to a high-hardness underground water physicochemical hardness removal method based on composite modified macroporous resin.

Background

The practical application of the invention is a No. five well and mine water treatment and utilization project of the West area of the great south lake, and in the process of construction diagram design and ordering and purchasing of electrodialysis equipment, it is found that calcium ions produced by ultrafiltration can reach about 40mg/L due to too high hardness of raw water in water quality, after RO system concentration is carried out, the calcium ion content of electrodialysis inflow water can reach 114mg/L, and electrodialysis manufacturers require that the calcium ion index of the inflow water of an electrodialysis normal system is less than 30 mg/L.

For the above reasons, the project of the present invention needs a hard water softening resin capable of effectively removing divalent cations in RO concentrated water, and the resin is preferably weakly acidic resin due to the process requirements of the project subsequent. Currently commercially available cation exchange resins achieve removal of heavy metal ions mainly by ion exchange through-SOH or-COOH, but have the following problems:

the main control mechanism of ion exchange is resin intraparticle diffusion, but the channels of resin intraparticle diffusion are susceptible to Ca²⁺、Mg²⁺Blockage interferes, and the efficiency of heavy metal removal is affected.

At present, a common solution to the above problems is to design a macroporous resin (macroporous resin is a general term for an ion exchange resin having a capillary structure inside a resin sphere particle) so as to reduce Ca²⁺、Mg²⁺The influence of (c). For the reasons mentioned above, such resins are mainly used for Pb²⁺、Cu²⁺、Ni²⁺And (4) removing.

The macroporous resins disclosed in the prior art are all produced in disorder, and the internal pore diameter of the particles except the surface may be in a closed pore state, so that the resin particle internal diffusion efficiency cannot be further improved, and Ca is not contained in the resin particles²⁺、Mg²⁺Is less effective than other divalent cations commonly found in mineral waters.

For the reasons, the invention aims to design the resin particles with orderly arranged inner pore diameters, reduce the problems of closed pores and low pore diameter utilization rate caused by disordered arrangement of the pore diameters, improve the internal diffusion efficiency of the resin particles and improve the Ca resistance of the resin²⁺、Mg²⁺The removal effect of (1).

Disclosure of Invention

In order to realize the aim, the invention provides a high-hardness groundwater physicochemical hardness removal method based on composite modified macroporous resin²⁺、Mg²⁺The specific technical scheme is as follows:

first, remove hard system

The invention discloses a high-hardness underground water physicochemical hardness removal method based on composite modified macroporous resin²⁺The concentration is more than or equal to 114mg/L, Mg²⁺Hardness of RO concentrated water with the concentration of more than or equal to 68mg/L is removed, and in the system:

the softener can remove divalent cations in RO concentrated water through the composite modified macroporous resin arranged in the softener, so that Ca in the water body flowing out of the hardness removal system²⁺The concentration is less than or equal to 0.5 mg/L.

Further, the generation amount of the RO concentrated water is 198m³H, the corresponding design treatment water amount of the hardness removal system is 198m³/h。

Furthermore, a regenerant used by the hardness removal system is hydrochloric acid with the concentration of 5%, the regeneration flow rate is 4-5 m/s, the regenerant used by the hardness removal system is hydrochloric acid with the concentration of 5%, the regeneration time is 45min, and the regeneration period is 15-18 h.

Further, the transformation agent used by the hardness removal system is sodium hydroxide with the concentration of 5%, the transformation flow rate is 4-5 m/s, and the transformation time is 45 min.

Furthermore, the backwashing agent used by the hard removing system is backflow soft water, the backwashing flow rate is 5-10 m/s, and the transformation time is 15 min.

Second, specific preparation method of composite modified macroporous resin

S1, preparing a GO two-dimensional template by adopting a quenching method;

s2, preparation of modified graphene oxide framework

In-situ polymerizing carboxylic acid and amide monomers on the GO two-dimensional template prepared in the step S1, and neutralizing the carboxylic acid and amide monomers by using a NaOH solution to obtain a modified graphene oxide skeleton, namely a P @ GO template;

s3 preparation of composite modified macroporous resin

S3-1, with H⁺Preparing sulfonyl chloride resin by using type polystyrene sulfonic acid resin as a raw material;

s3-2, mixing the sulfonyl chloride resin prepared in the step S3-1, the P @ GO template prepared in the step S2 and hexamethylene diamine/CH₂Cl₂Mixing, dissolving and mixing to react to prepare P @ GO intermediate resin; preparing an ordered self-supporting pore diameter in the P @ GO intermediate resin by adopting an ion regulation and control ice mold method to obtain a composite macroporous resin;

s3-3, washing the composite macroporous resin prepared in the step S3-2, and removing residual reactants to obtain the composite modified macroporous resin.

Further, the specific scheme of step S1 is as follows:

s1-1, mixing graphene oxide powder with a NaCl solution in a vacuum box, and then splashing the mixture on a precooling slide at the temperature of-60 ℃ at the height of 1-1.5 m to form a single-layer polycrystalline slice; the concentration of the graphene oxide in the mixed solution is 0.4-1.3 g/L, and the concentration of NaCl is 0.3-1.1 g/L;

s1-2, freezing the single-layer polycrystalline slice prepared in the step S1-1 at the annealing temperature of-30 to-10 ℃ for 1h, and obtaining the GO two-dimensional template after freeze drying.

The principle of step S1 is: when the mixed droplets were splashed onto a pre-cooled slide at-60 ℃, the droplets quickly spread onto the surface and immediately frozen into a thin sheet of polycrystalline ice. Because the temperature of the precooled slide glass is lower than the homogeneous nucleation critical temperature of ice, the homogeneous nucleation of ice occurs at the moment of freezing the liquid drops, a large number of micro ice crystals are generated, a layer of polycrystalline ice sheets is formed, and the graphene oxide sheets are uniformly dispersed among the ice crystals. The temperature is then maintained at the higher annealing temperature for a period of time during which large ice crystals grow to consume the smaller ice crystals, the average size of the ice crystals increases and the overall population decreases. Along with the process of recrystallizing ice crystal growth, the graphene oxide sheets are pushed into the gaps of the ice product, and after the recrystallization process tends to be stable, the sample is freeze-dried to obtain a corresponding GO two-dimensional template.

Further, the thickness of the pre-cooling slide glass used in the step S1-1 is 0.09-0.12 mm to ensure good thermal conductivity, and before use, the pre-cooling slide glass is sequentially cleaned with isopropanol, acetone and absolute ethyl alcohol for 20min to ensure the cleanliness of the frozen surface.

Further, the specific scheme of the step 2 is as follows:

s2-1, pouring methacrylamide, N-methylene bisacrylamide and acrylic acid into distilled water, and ultrasonically mixing uniformly at 35 ℃ to obtain a mixed solution; in the mixed solution, the concentration of methacrylamide is 5g/L, and the mass ratio of acrylamide, N-methylene bisacrylamide and acrylic acid is 1: 1: 3;

s2-2, adding the GO two-dimensional template prepared in the step S1 into the mixed solution prepared in the step S2-1, and magnetically stirring for 30min at 40 ℃; the concentration of the GO two-dimensional template in the mixed solution is 100 g/L;

s2-3, adding potassium persulfate into the mixed solution after magnetic stirring in the step S2-2, and reacting for 2.5 hours at a constant temperature of 50 ℃; in the step, the concentration of the sodium persulfate in the mixed solution is 1.1 g/L;

s2-4, firstly, filtering the mixed liquid in the step S2-3 to obtain a filtered product, washing the filtered product with distilled water until the supernatant is clear, then standing the filtered product in a sodium hydroxide solution with the pH of 10 for 30min, filtering, washing the filtered product with distilled water until the pH of the washing liquid is 7.5-8.0, and finally drying the washed filtered product at 60 ℃ for 12h to obtain the @ GO template.

The P @ GO template prepared in the step 2 has the following characteristics:

(1) the P @ GO template has good adsorption performance on calcium and magnesium ions in water;

(2) the preparation process of the P @ GO template is green and environment-friendly, and the carboxylic acid and amide copolymers loaded on the inner surface and the outer surface of the P @ GO template are not easy to elute;

(3) the P @ GO template has a long service life.

Further, the specific scheme of the step S3-1 is as follows:

S3-1-1、h is to be⁺Mixing polystyrene sulfonic acid resin with chloroform, and swelling for 24 h; h in the trichloromethane⁺The concentration of the polystyrene sulfonic acid resin is 200 g/L;

s3-1-2, mixing the mixed solution in the step S3-1-1 with a mixed solution with a volume ratio of 1: 1 SOCl₂/CHCl₃Mixing the mixed solution, refluxing for 8h at 80 ℃ by micro-boiling, and filtering to obtain solid particles after the reaction is finished; the mixed solution and SOCl in the step S3-1-1₂/CHCl₃The mixing volume ratio of the mixed solution is 1: 1;

s3-1-3, using CH₂Cl₂And (3) washing the solid particles prepared in the step S3-1-2 for 5-7 times, and drying in vacuum to obtain the sulfonyl chloride resin.

Further, the specific scheme of the step S3-2 is as follows:

s3-2-1, mixing the sulfonyl chloride resin prepared in the step S3-1, the P @ GO template prepared in the step S2, and a mixture of a sulfonyl chloride resin and a P @ GO template in a volume ratio of 1: 1 of hexamethylenediamine/CH₂Cl₂Mixing the mixed solution, and slightly boiling and refluxing for 1h at 60 ℃ to obtain P @ GO intermediate resin; the said and hexamethylenediamine/CH₂Cl₂The concentration of sulfonyl chloride resin in the mixed solution is 120-160 g/L, and the concentration of the P @ GO template is 30-60 g/L;

s3-2-2, adding a NaCl solution with the concentration of 0.3-1.2 g/L into the P @ GO intermediate resin prepared in the step S3-2-1 to prepare a precursor liquid, precooling the precursor liquid to 0 ℃, and then filling the precursor liquid into a reaction container to be directionally frozen to obtain a product; the temperature gradient of the directional freezing is-10 ℃, 15 ℃, 20 ℃, 30 ℃, 40 ℃, 60 ℃ and 80 ℃;

s3-2-3, continuously freezing the product subjected to the directional freezing treatment in the step S3-2-2 at the temperature of minus 40 ℃ for 12 hours, and continuously freezing and drying for 48 hours to obtain the composite macroporous resin.

The principle of preparing the oriented ordered pore size resin by the step S3-2 is as follows:

the whole mixed system is directionally frozen at different freezing temperatures (-10 ℃, -15 ℃, -20 ℃, -30 ℃, -40 ℃, -60 ℃, -80 ℃). In the directional freezing process, a single upward temperature gradient can be generated in the vertical direction, the solvent water firstly triggers nucleation and crystallization on the freezing surface of the P @ GO template close to the cold source, and then the ice crystals grow upwards along the vertical direction and are microtubular ice crystals. During the growth of ice crystals, the precursor solution is subjected to microphase separation: the solvent water crystallizes in a large range to form a frozen phase; the components in the precursor liquid are squeezed between the ice crystals and are gathered in micro liquid phase in the gaps of the ice crystals, and assembled and compressed to form a three-dimensional framework among the ice crystals. Then, the completely frozen sample is transferred to a refrigerator at-40 ℃ for further freezing for 12h, and the three-dimensional pore size is further formed stably. Finally, the ice crystals are completely removed by freeze drying for 48 hours.

Further, the reaction container used in the step S3-2-2 is composed of a pre-cooling slide glass and a polytetrafluoroethylene tube bonded on the pre-cooling slide glass, and the wall thickness of the polytetrafluoroethylene tube is 2.5-3 mm.

Further, the specific scheme of the step S3-3 is as follows:

s3-3-1, using CH₂Cl₂Washing the composite macroporous resin prepared in the step S3-2 for 5-7 times, and then washing with absolute ethyl alcohol for 4-5 times;

s3-3-2, soaking the composite macroporous resin washed in the step S3-3-1 in a sodium hydroxide solution with the pH value of 10 for 30min, and filtering to obtain a filtered product;

s3-3-3, washing the filtered product in the step S3-3-2 by deionized water until the pH value of the washing liquid is reduced to 7.5, and then drying the filtered product at 45 ℃ until the weight is constant to obtain the composite modified macroporous resin.

Compared with the existing groundwater physicochemical hardness removal method, the method has the beneficial effects that:

(1) the system for removing hardness of underground water by materialization can remove Ca²⁺The concentration is more than or equal to 114mg/L, Mg²⁺The RO concentrated water with the concentration more than or equal to 68mg/L is subjected to hardness removal, so that Ca in the water body flowing out of the hardness removal system²⁺The concentration is less than or equal to 0.5mg/L, and the calcium ion index of the water inlet of the electrodialysis normal system required by an electrodialysis manufacturer is met.

(2) The invention aims to improve the Ca content of macroporous weak acid cation exchange resin²⁺、Mg²⁺The orderly arranged three-dimensional pore diameter is constructed in the resin particles by taking the P @ GO template as a standard, and the internal diffusion of the resin particles is increasedDegree of Ca increase²⁺、Mg²⁺The removal rate of (3).

Drawings

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is a graph showing the dynamic adsorption curve of calcium and magnesium ions by a resin in an experimental example of the present invention;

FIG. 3 is a graph showing the effect of the amount of resin on the removal rate of calcium ions from water in the experimental examples of the present invention.

Detailed Description

In order to further illustrate the adopted modes and the obtained effects of the invention, the technical scheme of the invention is clearly and completely described by combining the embodiment and the experimental example.

Example 1

The main purpose of example 1 is to illustrate the data indexes of the hardness removal system designed by the present invention.

The invention discloses a high-hardness underground water physicochemical hardness removal method based on composite modified macroporous resin²⁺The concentration is more than or equal to 114mg/L, Mg²⁺The hardness of the RO concentrated water with the concentration of more than or equal to 68mg/L is removed, and the technical innovation of the invention is as follows:

in the system, the softener is provided with the composite modified macroporous resin. Through the composite modified macroporous resin, the softener can remove divalent cations in RO concentrated water, so that Ca in the water body flowing out of the hardness removal system²⁺The concentration is less than or equal to 0.5 mg/L.

Specifically, the generation amount of the RO concentrated water is 198m³H, the corresponding design treatment water amount of the hardness removal system is 198m³/h。

Specifically, the regenerant used in the hardness removal system is hydrochloric acid with the concentration of 5%, the regeneration flow rate is 4-5 m/s, the regeneration time is 45min, and the regeneration period is 15-18 h.

Specifically, the transformation agent used by the hardness removal system is sodium hydroxide with the concentration of 5%, the transformation flow rate is 4-5 m/s, and the transformation time is 45 min.

Specifically, the backwashing agent used by the hard removal system is backflow soft water, the backwashing flow rate is 5-10 m/s, and the transformation time is 15 min.

Example 2

Example 2 is mainly intended to illustrate a specific preparation method of the composite modified macroporous resin designed by the present invention, and the contents are as follows:

s1, preparing GO two-dimensional template

S1-1, mixing graphene oxide powder with a NaCl solution in a vacuum box, and then splashing the mixture on a precooling slide at the temperature of-60 ℃ at the height of 1m to form a single-layer polycrystalline slice; the concentration of the graphene oxide in the mixed solution is 0.4g/L, and the concentration of NaCl is 0.3 g/L;

s1-2, freezing the single-layer polycrystalline slice prepared in the step S1-1 at the annealing temperature of-30 ℃ for 1h, and obtaining a GO two-dimensional template after freeze drying;

s2, preparation of modified graphene oxide framework

S2-1, pouring 5g of methacrylamide, 5g N, N-methylene bisacrylamide and 15g of acrylic acid into 1L of distilled water, and ultrasonically mixing uniformly at 35 ℃ to obtain a mixed solution;

s2-2, adding 100g of the GO two-dimensional template prepared in the step S1 into the mixed solution prepared in the step S2-1, and magnetically stirring for 30min at 40 ℃;

s2-3, adding 1.1g of potassium persulfate into the mixed solution after magnetic stirring in the step S2-2, and reacting for 2.5 hours at a constant temperature of 50 ℃;

s2-4, firstly filtering the mixed liquid in the step S2-3 to obtain a filtered product, washing the filtered product with distilled water until the supernatant is clear, then standing the filtered product in a sodium hydroxide solution with the pH of 10 for 30min, filtering, washing the filtered product with distilled water until the pH of the washing liquid is 7.5, and finally drying the washed filtered product at 60 ℃ for 12h to obtain a P @ GO template;

s3 preparation of composite modified macroporous resin

S3-1, preparing sulfonyl chloride resin, and specifically comprising the following steps:

s3-1-1, mixing 200g of 732-CR with 1L of trichloromethane, and swelling for 24 hours;

the 732 cation exchange resin (732-CR) was supplied by Shanghai resin works and its physicochemical properties are shown in Table 1.

TABLE 1732 physicochemical Properties of CR

S3-1-2, mixing 1L of the mixed liquor in the step S3-1-1 with 1L of the mixed liquor in a volume ratio of 1: 1 SOCl₂/CHCl₃Mixing the mixed solution, refluxing for 8h at 80 ℃ by micro-boiling, and filtering to obtain solid particles after the reaction is finished;

s3-1-3, using CH₂Cl₂And (3) washing the solid particles prepared in the step S3-1-2 for 5 times, and drying in vacuum to obtain the sulfonyl chloride resin.

S3-2, preparing the composite macroporous resin, which comprises the following steps:

s3-2-1, mixing 120g of sulfonyl chloride resin prepared in the step S3-1, 30g of P @ GO template prepared in the step S2 and 1L of a mixed solvent with the volume ratio of 1: 1 of hexamethylenediamine/CH₂Cl₂Mixing the mixed solution, and slightly boiling and refluxing for 1h at 60 ℃ to obtain P @ GO intermediate resin;

s3-2-2, adding a NaCl solution with the concentration of 0.3g/L into the P @ GO intermediate resin prepared in the step S3-2-1 to prepare a precursor liquid, precooling the precursor liquid to 0 ℃, and then filling the precursor liquid into a reaction container for directional freezing to obtain a product; the temperature gradient of the directional freezing is-10 ℃, 15 ℃, 20 ℃, 30 ℃, 40 ℃, 60 ℃ and 80 ℃;

s3-2-3, continuously freezing the product subjected to the directional freezing treatment in the step S3-2-2 at the temperature of minus 40 ℃ for 12 hours, and continuously freezing and drying for 48 hours to obtain the composite macroporous resin;

s3-3, preparing the composite modified macroporous resin, which comprises the following steps:

s3-3-1, using CH₂Cl₂Washing the composite macroporous resin prepared in the step S3-2 for 5 times, and then washing with absolute ethyl alcohol for 4 times;

Specifically, the thickness of the pre-cooling slide glass used in the step S1-1 is 0.09mm to ensure good thermal conductivity, and before use, the pre-cooling slide glass is sequentially cleaned with isopropanol, acetone and absolute ethyl alcohol for 20min to ensure the cleanliness of the frozen surface.

Specifically, the reaction vessel used in step S3-2-2 is composed of a pre-cooling slide and a polytetrafluoroethylene tube bonded to the pre-cooling slide, and the wall thickness of the polytetrafluoroethylene tube is 2.5 mm.

Example 3

Example 3 is based on the scheme described in example 2, and aims to illustrate a specific preparation method of the composite modified macroporous resin under another parameter:

s1, preparing GO two-dimensional template

S1-1, mixing graphene oxide powder with a NaCl solution in a vacuum box, and then splashing the mixture on a precooling slide at the temperature of-60 ℃ at the height of 1m to form a single-layer polycrystalline slice; the concentration of graphene oxide in the mixed solution is 1.3g/L, and the concentration of NaCl is 1.1 g/L;

s1-2, freezing the single-layer polycrystalline slice prepared in the step S1-1 at the annealing temperature of-10 ℃ for 1h, and obtaining a GO two-dimensional template after freeze drying;

s2, preparation of modified graphene oxide framework

S2-1, pouring 20g of methacrylamide, 20g of 20g N, N-methylene bisacrylamide and 60g of acrylic acid into 2L of distilled water, and ultrasonically mixing uniformly at 35 ℃ to obtain a mixed solution;

s2-2, adding 200g of the GO two-dimensional template prepared in the step S1 into the mixed solution prepared in the step S2-1, and magnetically stirring for 30min at 40 ℃;

s2-3, adding 2.2g of potassium persulfate into the mixed solution after magnetic stirring in the step S2-2, and reacting for 2.5h at the constant temperature of 50 ℃;

s2-4, firstly filtering the mixed liquid in the step S2-3 to obtain a filtered product, washing the filtered product with distilled water until the supernatant is clear, then standing the filtered product in a sodium hydroxide solution with the pH of 10 for 30min, filtering, washing the filtered product with distilled water until the pH of the washing liquid is 8.0, and finally drying the washed filtered product at 60 ℃ for 12h to obtain a P @ GO template;

s3 preparation of composite modified macroporous resin

s3-1-1, mixing 200g of 732-CR with 2L of trichloromethane, and swelling for 24 hours;

s3-1-2, mixing the mixed liquor in the 2L step S3-1-1 with 2L of the mixed liquor with the volume ratio of 1: 1 SOCl₂/CHCl₃Mixing the mixed solution, refluxing for 8h at 80 ℃ by micro-boiling, and filtering to obtain solid particles after the reaction is finished;

s3-1-3, using CH₂Cl₂And (3) washing the solid particles prepared in the step S3-1-2 for 7 times, and drying in vacuum to obtain sulfonyl chloride resin.

s3-2-1, mixing 160g of sulfonyl chloride resin prepared in the step S3-1, 60g of P @ GO template prepared in the step S2 and 1L of a mixed solvent prepared by mixing the raw materials in a volume ratio of 1: 1 of hexamethylenediamine/CH₂Cl₂Mixing the mixed solution, and slightly boiling and refluxing for 1h at 60 ℃ to obtain P @ GO intermediate resin;

s3-2-2, adding a NaCl solution with the concentration of 1.2g/L into the P @ GO intermediate resin prepared in the step S3-2-1 to prepare a precursor liquid, precooling the precursor liquid to 0 ℃, and then filling the precursor liquid into a reaction container for directional freezing to obtain a product; the temperature gradient of the directional freezing is-10 ℃, 15 ℃, 20 ℃, 30 ℃, 40 ℃, 60 ℃ and 80 ℃;

s3-3-1, using CH₂Cl₂Washing the composite macroporous resin prepared in the step S3-2 for 5 times, and then washing the composite macroporous resin for 5 times by using absolute ethyl alcohol;

Specifically, the thickness of the pre-cooling slide glass used in the step S1-1 is 0.12mm to ensure good thermal conductivity, and before use, the pre-cooling slide glass is sequentially cleaned with isopropanol, acetone and absolute ethyl alcohol for 20min to ensure the cleanliness of the frozen surface.

Specifically, the reaction vessel used in the step S3-2-2 is composed of a pre-cooling slide and a polytetrafluoroethylene tube bonded to the pre-cooling slide, and the wall thickness of the polytetrafluoroethylene tube is 3 mm.

Examples of the experiments

The experimental example is described based on the scheme described in example 2, and aims to clarify the specific properties of the composite modified macroporous resin prepared by the invention.

1. Design of experiments

To illustrate the specific properties of the composite modified macroporous resin prepared in accordance with the present invention, the following experimental group was designed, and for visual comparison, a commercial resin-732-CR was used as a blank in this example, and the basic parameters of the commercial resin are shown in Table 1 above.

Blank group: commercial resin-732-CR in Table 1;

experimental group 1: using the protocol described in example 1, sulfonyl chloride resin was prepared from sulfonyl chloride resin without using an ice mold method;

experimental group 2: using the protocol described in example 1, with hexamethylenediamine/CH₂Cl₂Preparing hexamethylenediamine modified polystyrene macroporous resin by using the mixed solution and sulfonyl chloride resin as raw materials without adopting an ice mold method;

experimental group 3: using the protocol described in example 1, with sulfonyl chloride resin, GO two-dimensional template, hexamethylenediamine/CH₂Cl₂Preparing GO/composite modified macroporous resin by using the mixed solution as a raw material without adopting an ice mold method;

experimental group 4: using the protocol described in example 1, with sulfonyl chloride resin, P @ GO template, hexamethylenediamine/CH₂Cl₂Preparing PGO/composite modified macroporous resin by using the mixed solution as a raw material without adopting an ice mold method;

experimental group 5: using the protocol described in example 1, with sulfonyl chloride resin, P @ GO template, hexamethylenediamine/CH₂Cl₂Preparing P @ GO/composite modified macroporous resin by using the mixed solution as a raw material by adopting an ice mold method;

2. influence of different synthetic methods on numerical specific surface area

Blank groups and experimental groups 1-6 are selected, the specific surface area of each group of resin is measured, and specific data are shown in table 2.

TABLE 2 Carrier hydrophilicity

Referring to the data in Table 2, it can be seen that the specific surface area of 732-CR currently commercially available is 443m²The reason why the specific surface area of the sulfonyl chloride resin prepared in experimental group 1 is lower than that of 732-CR is presumed to be that the 732-CR is re-swollen to destroy the original pore size structure of 732-CR without constituting a new pore size structure, resulting in a decrease in specific surface area.

Comparing the experimental groups 2, 3 and 4 with the blank group, it can be found that the specific surface areas of the resins prepared by the experimental groups 2, 3 and 4 are slightly higher than 732-CR, but the difference is not large, and the difference between the specific surface areas of the resins among the experimental groups 2, 3 and 4 is also small, and whether the GO two-dimensional template and the P @ GO template are added or not is presumed, the specific surface area of the resin cannot be changed, and the decisive effect on the formation of the pore diameter structure of the resin is not achieved.

It is to be noted that the specific surface area of the resin prepared in Experimental group 5 was much higher than that of the other groups (the specific surface area of the resin in Experimental group 5 was 513m²The/g) because the ice mold method is adopted, the components in the precursor liquid are squeezed between the ice crystals in the directional freezing process and are gathered in the micro liquid phase in the gaps of the ice crystals, and then the pore diameter with the three-dimensional structure is formed.

Therefore, in the present experimental example, the method of preparing the resin having a large specific surface area is preferably an ice mold method.

2. Influence of NaCl solution concentration in precursor solution on resin morphology

Based on the scheme in the experimental group 5, the following experimental group is designed to explore the influence of the concentration of the NaCl solution in the precursor solution on the morphology of the resin, and the specific data are shown in table 3.

TABLE 3 influence of NaCl solution concentration in the precursor solution on the morphology of the resin

Referring to the data in table 3, regarding the variation of the pore size of the resin, it can be seen that when the concentration of the NaCl solution is 0.1g/L, the pore size of the prepared resin is 0.3nm at the minimum and 4.3nm at the maximum, i.e. the difference of pore sizes is very large (difference is 4.0nm), and the directional pore-forming effect is not good; when the concentration of the NaCl solution is gradually increased to 1.9g/L, the pore diameter of the prepared resin is 2.1nm at the minimum and 2.8nm at the maximum, and the minimum pore and the maximum pore are reduced, namely the difference of the pore diameters is reduced (the difference is 0.7nm), which shows that the prepared resin has better directional pore-forming effect and the pore diameters with uniform particle sizes are obtained. However, it is noted that when the NaCl solution concentration was increased to 1.2g/L, the minimum and maximum pore numbers of the obtained resin were both decreased (pore diameter was 0.8nm at the minimum and 1.9nm at the maximum), and the difference in pore diameter was abruptly increased (difference was 1.1 nm).

Referring to the data in Table 3, in terms of the thickness variation between the pore diameters of the resin, it can be seen that the pore diameter thickness of the prepared resin gradually becomes thicker (0.3 to 3.2nm) as the concentration of the NaCl solution gradually increases.

In combination with the above, as the concentration of the NaCl solution is gradually increased, the pore diameter thickness of the resin is gradually increased from thin to thick. When the concentration of the NaCl solution is 0.1g/L, although the reticular pore diameter is obtained and the resin structure is compactly reinforced, the pore diameter distribution is not uniform, which can cause poor mechanical transformation performance; as the NaCl solution concentration gradually increases to 1.9g/L, more resin components are repelled by the particle ice crystals and are compressed among the ice crystals, so that the pore size distribution is more uniform and ordered. However, when the concentration of NaCl solution is increased to 1.2g/L, the pore size is blocked due to the thick wall between the pores, the ordered formation of the pore size is destroyed, and the phenomenon that the difference of the pore size is suddenly increased is shown.

Therefore, in this experimental example, in order to obtain a resin material having small pore diameter variation and uniform pore diameter, the concentration of NaCl solution is preferably 1.9 g/L.

3. Dynamic analysis of calcium and magnesium ions by resin under flowing water condition

Fig. 2 is a dynamic adsorption curve of calcium and magnesium ions by the composite modified macroporous resin prepared by the method under different flow rates. In this experimental example, a mixed solution of simulated calcium and magnesium ions having a concentration of 500ppm (in terms of calcium carbonate) and a concentration of 4:1 of calcium and magnesium ions was used. The outlet flow rates were 5.0, 15.0, 30.0mL/min, respectively.

Comparing the three dynamic adsorption curves, it can be seen that the smaller the flow rate, the better the adsorption effect of the resin, and the higher the removal rate of calcium and magnesium ions, which can reach 99.6% at most, and the other two adsorption curves are 92.3% and 87.4% in sequence. It is noted that, as the adsorption time is prolonged, the adsorption effect of the resin is gradually deteriorated, and the removal rate of calcium and magnesium ions is gradually reduced. This is because as the adsorption proceeds, the resin adsorbs a certain amount of adsorbate, and some functional groups in the resin are already aggregated with calcium and magnesium ions, resulting in a gradual decrease in adsorption rate. Therefore, in practical use, the outlet flow rate of the drinking water is controlled, so that the treated resin can meet the requirement of hardness of the drinking water, and the service life of the resin can be prolonged to the maximum extent.

4. Influence of resin dosage on removal rate of calcium ions in water

FIG. 3 is a graph showing the effect of the amount of the modified macroporous resin composition prepared in the present application on the removal rate of calcium ions in water. From fig. 3, it can be seen that, by changing the amount of the composite modified macroporous resin added while keeping the calcium ion concentration at 500ppm (in terms of calcium carbonate) and the volume of water at 100mL, the removal rate of calcium ions increases with the increase of the amount of the resin used, and when the amount of the composite modified macroporous resin added is 0.11g, the removal rate of calcium ions in water reaches nearly 100%.

5. Practical application

The practical application of the invention utilizes project design purchasing and construction management general contract project for No. five well water treatment in the West area of the great south lake, the place is the east part of the West area of the great south lake of the south Tu Ha coal field in Xinjiang Hami city, and the company is Xuan mine group Hami energy limited company.

Item information: treatment scale: producing 100m of water³The method comprises the following steps of (1) constructing 4 sets of the Perx 5 sets at a time, and reserving 1 set of the positions; the hardness of underground mine water is high, most of the underground mine water is permanent hardness, and the underground mine water needs to be softened by caustic soda and calcined soda, and then enters reverse osmosis after being pretreated after the hardness is removed. The details of the hardness removal system are shown in Table 4.

TABLE 4 hard removal System details

Raw water type: the third-level wastewater has SDI less than 2.5.

The water quality parameters of each stream within the RO are shown in table 5.

TABLE 5 Water quality parameters of the streams in RO

The effect of the hardness removal system on removing calcium from RO water based on the composite modified macroporous resin prepared by the invention is shown in Table 6.

TABLE 6 calcium removal effect of the hardness removal System

The data in table 6 show that, in an alkaline state (PH is greater than or equal to 11.5), the composite modified macroporous resin can greatly reduce calcium and magnesium ions in the RO concentrated water, and can reduce the hardness of the raw water from 300mg/L to 1.5mg/L, that is, the hardness of calcium ions is reduced from 120mg/L to 0.5mg/L, so that the requirement that the calcium ions in the feed water of electrodialysis are less than 1.84mg/L can be met, and the scaling risk formed by calcium sulfate in an electrodialysis system can be effectively avoided.

The principle of the RO concentrated water calcium removal process can be known as follows: only the effluent of the ion exchange resin can completely remove calcium ions, and the requirement of calcium ion concentration of the electrodialysis influent water is met, so in the experimental example, the RO concentrated water softening scheme is preferably performed by adopting composite modified macroporous resin, 3% -5% de HCL is adopted for regeneration, the regenerated solution is enriched with divalent cations such as high-concentration calcium, magnesium and the like, and can be continuously returned to the system for chemical softening removal.

In addition, in the application engineering of the invention, the concentration of the fluorinion in the raw water is 0.9mg/L, the concentration of the fluorinion after RO concentration is 2.55mg/L, and CaF₂Has a KSP constant of 2.7X 10^-11The solubility of calcium fluoride is 14mg/L, the fluorine ion is 7.16mg/L, the calcium ion is 7.54mg/L, and the calcium ion exceeds the concentration to form fluoridation scale, so that the effective removal of the calcium ion in the RO concentrated water is very important for the normal operation of the system.

Although barium ions and strontium ions are not detected in raw water of the engineering, barium sulfate, strontium sulfate, calcium carbonate and the like are substances which are easy to form scales, divalent cations such as calcium, magnesium, barium, strontium and the like are also very necessary to be removed through ion exchange softening, and meanwhile, the ion exchange softening is a process which is often adopted in a zero-emission process, so that the process of removing the divalent calcium and magnesium ions by adopting the modified macroporous resin to RO concentrated water is very important to the engineering and is a process which must be adopted.

Claims

1. A physicochemical hardness removal method for high-hardness underground water based on composite modified macroporous resin is characterized in that a hardness removal system consisting of a soft water pump, a softener and a resin catcher is used for removing Ca²⁺The concentration is more than or equal to 114mg/L, Mg²⁺Hardness of RO concentrated water with the concentration of more than or equal to 68mg/L is removed, and in the system:

the softener can remove RO concentrated water through the composite modified macroporous resin arranged in the softenerDivalent cations in (1) to make Ca in the water body flowing out of the hardness removing system²⁺The concentration is less than or equal to 0.5 mg/L.

2. The method for materializing and removing the hardness of the high-hardness underground water based on the composite modified macroporous resin as claimed in claim 1, wherein the generation amount of the RO concentrated water is 198m³H, the corresponding design treatment water amount of the hardness removal system is 198m³/h。

3. The high-hardness underground water physicochemical hardness removal method based on the composite modified macroporous resin as claimed in claim 1, wherein a regenerant used in the hardness removal system is hydrochloric acid with a concentration of 5%, the regeneration flow rate is 4-5 m/s, the regeneration time is 45min, and the regeneration period is 15-18 h.

4. The high-hardness underground water physicochemical hardness removal method based on the composite modified macroporous resin as claimed in claim 1, wherein the transformation agent used by the hardness removal system is sodium hydroxide with the concentration of 5%, the transformation flow rate is 4-5 m/s, and the transformation time is 45 min.

5. The high-hardness underground water physicochemical hardness removal method based on the composite modified macroporous resin as claimed in claim 1, wherein the backwashing agent used by the hardness removal system is backflow soft water, the backwashing flow rate is 5-10 m/s, and the transformation time is 15 min.

6. The composite modified macroporous resin used in the physicochemical hardness removal method according to claim 1, wherein the specific preparation method of the composite modified macroporous resin is as follows:

s1, preparing a GO two-dimensional template by adopting a quenching method;

s2, preparation of modified graphene oxide framework

s3 preparation of composite modified macroporous resin

7. The method for preparing the composite modified macroporous resin as claimed in claim 6, wherein the specific scheme of the step 2 is as follows:

8. The method for preparing the composite modified macroporous resin as claimed in claim 6, wherein the specific scheme of the step S3-2 is as follows: