Preparation method and application of imprinting material for removing nitrate in drinking underground water

文档序号：1961024 发布日期：2021-12-14 浏览：19次中文

阅读说明：本技术 一种用于去除饮用地下水中硝酸盐的印迹材料制备方法和应用 (Preparation method and application of imprinting material for removing nitrate in drinking underground water ) 是由董军李文德夏添梁雪于 2021-07-28 设计创作，主要内容包括：本发明涉及一种用于去除饮用地下水中硝酸盐的印迹材料制备方法和应用,硝酸盐的离子印迹材料以硝酸钠为模板,二甲基二烯丙基氯化铵和丙烯酰胺为功能单体,二甲基丙烯酸乙二醇脂为交联剂,偶氮二异丁腈为引发剂,利用本体聚合反应技术制备,其对硝酸根具有快速的吸附能力,可应用于分散式农村饮用地下水中硝酸盐靶向吸附方面。本发明分别探究了模板和功能分子的预组装时间以及材料中各组分比例对材料饱和吸附量的影响。最终开发的硝酸盐的离子印迹材料对硝态氮的饱和吸附容量为14.876mg/L,具有较好的吸附性,相对于SO-(4)～(2-),材料对NO-(3)～(-)的选择性系数为1.833,具有良好的选择性。(The invention relates to a preparation method and application of a blotting material for removing nitrate in drinking groundwater. The invention respectively explores the influence of the preassembly time of the template and the functional molecule and the proportion of each component in the material on the saturated adsorption capacity of the material. The finally developed nitrate ion imprinted material has the saturated adsorption capacity of 14.876mg/L for nitrate nitrogen, has better adsorbability, and is relative to SO 4 2‑ Material to NO 3 ‑ The selectivity coefficient of (A) is 1.833, and good selectivity is achieved.)

1. A preparation method of a blotting material for removing nitrate in drinking underground water is characterized in that nitrate is used as template ions, dimethyl diallyl ammonium chloride and acrylamide are used as functional monomers, ethylene glycol dimethacrylate is used as a cross-linking agent, and azobisisobutyronitrile is used as an initiator, and the blotting material is prepared by a bulk polymerization method and is a porous solid.

2. The method for preparing the blotting material for removing nitrate from drinking groundwater according to claim 1, comprising the steps of:

A. pre-assembling imprinting materials: respectively adding a proper amount of template molecule sodium nitrate, functional monomers dimethyl diallyl ammonium chloride and acrylamide into a mixed solution of N, N dimethyl formamide and methanol, and stirring and pre-assembling at normal temperature for 6-24 h;

B. polymerization of the material: heating the prepared liquid after pre-assembly in a 65 ℃ water bath, sequentially adding a proper amount of cross-linking agent ethylene glycol dimethacrylate and initiator azobisisobutyronitrile into a reaction vessel, and synthesizing a porous solid polymer by using a bulk polymerization method in a closed environment;

C. cleaning and drying materials: cooling the synthesized material to room temperature, and then washing the material with absolute ethyl alcohol, NaCl solution and deionized water until no nitrate is detected in the eluent; and (3) drying the cleaned imprinting material in a vacuum drying oven at 45 ℃ for 12h, and then transferring the imprinting material to a freeze drying oven for drying for 12 h.

3. The method for preparing the blotting material for removing nitrate from drinking groundwater as claimed in claim 2, wherein: step A, the preassembly time is 12 h.

4. The method for preparing the blotting material for removing nitrate from drinking groundwater according to claim 3, wherein: the molar ratio of the template molecules to the functional monomers to the cross-linking agent is as follows: 1: 1-10: 1 to 7.

5. The method for preparing the blotting material for removing nitrate from drinking groundwater according to claim 4, wherein: the molar ratio of the template molecules to the functional monomers to the cross-linking agent is 1: 10: 5.

6. the method for preparing the blotting material for removing nitrate from drinking groundwater according to claim 4, wherein: the molar ratio of the template molecules to the initiator is as follows: 1: 5.

7. the method for preparing the blotting material for removing nitrate from drinking groundwater according to claim 4, wherein: the molar ratio of the functional monomers dimethyl diallyl ammonium chloride to acrylamide is as follows: 1: 1.

8. the method for preparing the blotting material for removing nitrate from drinking groundwater as claimed in claim 2, wherein: the template molecule sodium nitrate is 0-1.7g, the functional monomer dimethyl diallyl ammonium chloride is 5.38g, the acrylamide is 1.421g, and the ethylene glycol dimethacrylate is 1.982-13.875 g.

9. The method for preparing the blotting material for removing nitrate from drinking groundwater as claimed in claim 1, wherein: the prepared nitrate imprinting material can be applied to nitrate target adsorption treatment in underground water for drinking in distributed rural areas.

Technical Field

The invention belongs to the technical field of new materials for removing nitrate in underground water, and particularly relates to a preparation method of a imprinted material for selectively adsorbing nitrate ions and application of the imprinted material in nitrate targeted adsorption of nitrate in distributed rural drinking underground water.

Background

Underground water is the most main source of drinking water in rural areas in northern areas of China, nitrate in the underground water can directly harm the body health of residents in the rural areas, the residents can cause human diseases if drinking water with excessive nitrate content is taken for a long time, and cancers are seriously caused. Compared with the characteristics that residents in rural areas in northern China are small in inhabitation and wide in area, the residents are relatively dispersed in urban population, the daily water consumption is small, the fluctuation is large along with seasonal variation, most of groundwater drinking water in the rural areas is taken by distributed self-exploiting wells, and the system has the typical characteristics of distributed groundwater water sources such as large quantity, wide distribution, small scale and the like. Because the centralized treatment amount per day is small, the centralized urban drinking water solution cannot be applied to removing nitrate from drinking underground water in vast rural areas, and the characteristic of distributed water collection in the rural areas brings great difficulty to the removal of nitrate. Therefore, a scheme for properly and efficiently removing nitrate is required to be provided aiming at the characteristics of distributed rural drinking water.

For counties with relatively concentrated resident population, the physical method of utilizing a semi-permeable membrane and ion exchange resin to adsorb nitrate in drinking water is common, and the main mechanism is to enrich and concentrate nitrate nitrogen and transfer the enriched concentrated solution to other places for secondary treatment. The ion enrichment process is non-selective, and the semi-permeable membrane and the ion exchange resin can adsorb non-target ions while adsorbing nitrate nitrogen in the polluted water body, so that the material utilization rate is reduced. In the chemical method for removing nitrate nitrogen, the reducing agent not only reduces the nitrate nitrogen into ammonia nitrogen or nitrogen, but also reduces other oxidizing substances in the polluted water body, so that the reducing agent is consumed purposelessly, nitrate is preferentially adsorbed on an anode due to negative electricity of the nitrate in electrochemical catalysis, nitrate reduction occurs on a cathode, and the electrochemical catalysis efficiency is reduced. In summary, the non-selectivity of nitrate removal methods reduces the efficiency of drinking water purification and increases the cost of decentralized drinking groundwater removal, which increases the cost of water usage in relatively laggard rural areas, and it is therefore desirable to find a method to reduce the unintended consumption of materials in the nitrate conversion removal process.

The imprinting material is an adsorbent with selective adsorption function, imprinting cavities formed in the preparation process are highly matched with the template in the aspects of size, space structure, binding sites and the like, so that the imprinting material has specific selectivity and excellent binding affinity to the template, and can selectively adsorb specific pollutants from drinking water. The imprinting material comprises molecular imprinting and ion imprinting, wherein the ion imprinting is divided into cationic imprinting material and anionic imprinting material. Nitrate radical is a common anionic pollutant of drinking water, the ionic radius of the nitrate radical is small, the ionic functionalization is weak, the complex effect with functional monomers is not easy to generate, effective template recognition sites are difficult to establish, the electrostatic adsorption capacity of the nitrate radical is poorer than that of cation in the adsorption process, but anions such as nitrate radical are also common pollutants in drinking underground water. Therefore, the development of the material with the nitrate radical targeted adsorption function has important significance for the high-efficiency treatment of nitrate in rural drinking underground water.

Disclosure of Invention

The invention aims to provide a preparation method of a blotting material capable of selectively adsorbing nitrate ions and also provides application of the blotting material capable of selectively adsorbing nitrate ions in nitrate-targeted adsorption in dispersed rural drinking groundwater so as to solve the problems of low removal efficiency and difficult removal of nitrate in dispersed rural drinking water caused by non-targeted reaction in the existing method for removing nitrate in drinking groundwater through conversion.

The purpose of the invention is realized by the following technical scheme:

a preparation method of a blotting material for removing nitrate in drinking underground water is characterized in that nitrate is used as template ions, dimethyl diallyl ammonium chloride and acrylamide are used as functional monomers, ethylene glycol dimethacrylate is used as a cross-linking agent, and azobisisobutyronitrile is used as an initiator, and the blotting material is prepared by a bulk polymerization method and is a porous solid.

The preparation method of the imprinting material for removing the nitrate in the drinking groundwater specifically comprises the following steps:

Further, step a, the preassembly time is 12 h.

Further, the molar ratio of the template molecule, the functional monomer and the cross-linking agent is as follows: 1: 1-10: 1 to 7.

Further, the mole ratio of the template molecule, the functional monomer and the cross-linking agent is 1: 10: 5.

further, the molar ratio of the template molecule to the initiator is: 1: 5.

furthermore, the mole ratio of the functional monomers dimethyl diallyl ammonium chloride and acrylamide is as follows: 1: 1.

furthermore, the template molecule sodium nitrate is 0-1.7g, the functional monomer dimethyl diallyl ammonium chloride is 5.38g, the acrylamide is 1.421g, and the ethylene glycol dimethacrylate is 1.982-13.875 g.

The ionic imprinting material of the nitrate is applied to the nitrate nitrogen pollution treatment of drinking underground water, in particular to the application of nitrate target adsorption in the drinking underground water of distributed rural areas.

Compared with the prior art, the invention has the beneficial effects that:

the invention utilizes the ion exchange principle, uses dimethyl diallyl ammonium chloride and acrylamide containing C ═ C and amino as functional monomers, uses ethylene glycol dimethacrylate as a cross-linking agent, uses azobisisobutyronitrile as an initiator, prepares a nitrate ion imprinting material by a bulk polymerization method, and is applied to the treatment of nitrate nitrogen pollution of drinking groundwater, the saturated adsorption capacity of the ion imprinting material to the nitrate nitrogen is 14.876mg/L, the ion imprinting material has better adsorbability, and compared with SO, the ion imprinting material has the advantages that the saturated adsorption capacity is 14.876mg/L, the adsorption capacity is higher, and the adsorption capacity is higher₄ ^2-Material to NO₃ ^-The selectivity coefficient of (A) is 1.833, and good selectivity is achieved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a synthesized nitrate-targeted adsorption material;

2 a-2 d are SEM images of the surface of the nitrate-targeted adsorbent material particles;

FIG. 3 is a graph of the effect of different pre-assembly times on the adsorption performance of an ion imprinting material;

FIG. 4 shows the influence of the ratio of functional monomers to cross-linking agents on the adsorption performance of the ion imprinting material;

FIG. 5 shows the influence of the ratio of template molecules to functional monomers on the adsorption performance of the ion imprinted material;

FIG. 6 is a flow chart of a method of making a blotting material for removing nitrate from drinking groundwater.

Detailed Description

The present invention will be further described with reference to specific embodiments, which are implemented on the premise of the technology of the present invention, and detailed embodiments are given, but the scope of the present invention is not limited to the following examples.

A preparation method of a blotting material for removing nitrate in drinking underground water is characterized in that nitrate is used as template ions, dimethyl diallyl ammonium chloride and acrylamide are used as functional monomers, ethylene glycol dimethacrylate is used as a cross-linking agent, and azobisisobutyronitrile is used as an initiator, and the blotting material is prepared by a bulk polymerization method and is a porous solid.

The preparation method of the imprinting material for removing the nitrate in the drinking groundwater specifically comprises the following steps:

A. pre-assembling imprinting materials: weighing 0-1.7g of template molecule sodium nitrate, 5.38g of functional monomer dimethyl diallyl ammonium chloride and 1.421g of acrylamide, adding into a mixed solution of N, N-dimethylformamide and methanol, stirring at normal temperature, and pre-assembling for 6-24 h;

B. polymerization of the material: heating the prepared liquid after pre-assembly in a water bath kettle at 65 ℃, sequentially adding 1.982-13.875g of cross-linking agent ethylene glycol dimethacrylate and 0.821g of initiator azobisisobutyronitrile into a reaction container, sealing the container after the material addition is finished, and synthesizing a porous solid polymer by a bulk polymerization method;

C. cleaning and drying materials: cooling the synthesized material to room temperature, then placing the cooled material in absolute ethyl alcohol for washing for 5 times to remove a mixed solvent and unreacted organic materials in a reaction system, then placing the material in 5g/L NaCl solution for washing for 5 times to elute template ion nitrate radicals in the material until no nitrate radical is detected in an eluent, and finally washing impurities remained on the surface of solid particles by deionized water; and (3) drying the cleaned imprinting material in a vacuum drying oven at 45 ℃ for 12h, and then transferring the imprinting material to a freeze drying oven for drying for 12 h.

The nitrate ion imprinting material can be applied to nitrate target adsorption in the drinking underground water in the decentralized rural areas.

Examples 1-4 mainly explore the effect of pre-assembly time on the adsorption capacity of the ion imprinted material.

Example 1

A preparation method of a blotting material for removing nitrate in drinking groundwater comprises the following steps:

A. weighing 0.85g of template molecule sodium nitrate, 5.38g of functional monomer dimethyl diallyl ammonium chloride and 1.421g of acrylamide in a 250mL silk-mouth reagent bottle, simultaneously weighing 40mL of N, N-dimethylformamide and 10mL of methanol, adding the mixture into the silk-mouth reagent bottle, placing the bottle in a water bath shaker at 25 ℃, and oscillating for 12 hours to obtain a polymerization reaction preparation solution.

B. Transferring the silk reagent bottle containing the preparation solution into a 65 ℃ water bath kettle, sequentially adding 9.911g of crosslinking agent ethylene glycol dimethacrylate and 0.821g of initiator azobisisobutyronitrile into the reaction container, and sealing the container after the materials are added. The polymerization was heated for 3 h.

C. And cooling the synthesized solid material to room temperature, then placing the cooled solid material in absolute ethyl alcohol for washing for 5 times to remove a mixed solvent and unreacted organic materials in a reaction system, then placing the imprinted material in a 5g/L NaCl solution for washing for 5 times, eluting template ion nitrate in the material until no nitrate is detected in the eluent, and finally washing impurities remained on the surfaces of solid particles by using deionized water. And (3) drying the cleaned imprinting material in a vacuum drying oven at 45 ℃ for 12h, and then transferring the imprinting material into a freeze drying oven for drying for 12 h.

Example 2