Disclosure of Invention
The invention aims to provide a chelating resin, a preparation method and application thereof, which are used for purifying water or treating metal ion wastewater.
The purpose of the invention can be realized by the following technical scheme: a chelating resin having the structure shown below:
wherein R is selected from H and C1-C10Any one or more of straight chain or branched chain alkyl or alkoxy, chlorine and bromine;
R1radical is selected from (CH)2)nOH, said R2Radical is selected from (CH)2)nCOOH, n is 0-3;
indicating chlorine spheres having different degrees of crosslinking.
Preferably, n is 0.
Preferably, in the chelating resin, the functional groups are hydroxyl and carboxyl, and the content of the functional groups is 1.00-2.00 mmol/g. The chelating resin of the invention chelates metal ions through carbonyl oxygen and hydroxyl oxygen atoms in the radical.
The preparation method of the chelate resin has the following reaction general formula:
the method specifically comprises the following steps:
(1) pretreatment: specifically, deionized water and ethanol are used as detergents, the mixture is stirred at room temperature, and the chlorine ball is washed for multiple times to remove impurities in the chlorine ball.
(2) Adding a certain amount of methanol and sulfuric acid into the 2, 4-dihydroxyphenyl carboxylic acid compounds to carry out esterification reaction to obtain the 2, 4-dihydroxyphenyl carboxylic acid methyl ester compounds.
(3) And (3) sequentially adding a solvent into a reaction bottle containing a certain mass of pretreated chlorine balls for swelling, the obtained product in the step (2), an acid-binding agent, potassium iodide and tetrabutyl ammonium chloride, heating and refluxing for substitution reaction, separating out resin after the reaction is finished, washing the resin for multiple times by using the solvent, and drying the resin in vacuum to constant weight to obtain the 2-hydroxyphenyl carboxylic acid methyl ester resin compound.
(4) And (3) adding alkali liquor into the reaction bottle with the product obtained in the step (3), heating to perform hydrolysis reaction, separating out resin after the reaction is finished, washing the resin to be neutral for multiple times by using a solvent, and drying the resin in vacuum to constant weight to obtain the novel chelate resin.
The method takes 2, 4-dihydroxy benzoic acid as a raw material, and synthesizes the chelate resin through three steps of esterification protection of carboxyl, reaction with chloromethylated polystyrene resin, and hydrolysis to remove the protective group of carboxyl.
Preferably, the chlorine ball in the step (3) is any one of chloromethylated polystyrene-divinylbenzene resin with different crosslinking degrees. The preferred degree of crosslinking is 4%.
Preferably, the solvent for swelling the chlorine spheres in the step (3) is any one of acetone, ethanol, 1, 4-dioxane, dichloromethane, dimethyl sulfoxide, N-dimethylformamide, benzene and diethyl ether. The swelling solvent is preferably acetone.
Preferably, the swelling time in the step (3) is 6-12 h, preferably 10 h.
Preferably, the acid-binding agent in the step (3) is any one of anhydrous potassium carbonate, anhydrous sodium carbonate, triethylamine, tri-N-propylamine and N, N-diisopropylethylamine. The preferred acid-binding agent is anhydrous potassium carbonate.
Preferably, the molar ratio of the chlorine ball, the 2, 4-dihydroxy phenyl carboxylic acid methyl ester compound and the acid-binding agent in the step (3) is 1 (1.5-3) to (1-2). The preferred feed ratio is 1:2: 1.5. The methyl 2, 4-dihydroxyphenyl carboxylate compound is preferably methyl 2, 4-dihydroxybenzoate.
Preferably, the amount of potassium iodide and tetrabutylammonium chloride are catalyst equivalent.
Preferably, the solvent used for washing after the substitution reaction in the step (3) is any one or a mixture of several of absolute ethyl alcohol, dichloromethane, methanol, n-hexane, deionized water, 1, 4-dioxane and acetone, and preferably absolute ethyl alcohol and acetone;
the solvent used for washing in the hydrolysis reaction in the step (4) is any one or a mixture of several of absolute ethyl alcohol, dichloromethane, methanol, n-hexane, deionized water, 1, 4-dioxane and acetone, and preferably absolute ethyl alcohol and acetone.
Preferably, the alkali liquor in the step (4) is any one of a sodium hydroxide solution and a potassium hydroxide solution, and preferably, the alkali liquor is a sodium hydroxide solution.
Preferably, the heating reflux and the reaction time specifically include:
performing esterification reaction at 40-100 ℃ for 12-24 hours; the temperature is preferably 65 ℃ and the reaction time is 20 hours.
Performing substitution reaction at the temperature of 60-100 ℃ for 8-24 hours; the temperature is preferably 80 ℃ and the reaction time is 12 hours.
Performing hydrolysis reaction at 40-90 ℃ for 8-24 hours; the preferred temperature is 50 ℃ and the reaction time is 12 hours.
The chelating resin is used for removing metal ions in wastewater with different acidity, and the metal ions are one or more of nickel, cobalt, manganese, calcium, magnesium, iron, zinc and copper ions.
Preferably, the removing process comprises the steps of:
s1: changing the chelating resin into Na type, and mixing and balancing the Na type chelating resin with a sodium hydroxide solution, a sodium chloride solution or a sodium sulfate solution;
s2: mixing Na-type chelating resin with solution containing metal ions for balancing.
Further preferably, the removing process further specifically includes the following steps:
(a) filling chelating resin in an exchange column, and enabling a solution containing nickel ions, cobalt ions, manganese ions, calcium ions, magnesium ions, iron ions, zinc ions and copper ions with the original concentration of 1.00g/L to pass through the chelating resin layer from top to bottom at a certain flow rate.
(b) The concentration of metal ions in the solution flowing out of the exchange column (a) is lower than 6mg/L through the detection of an inductively coupled plasma spectrometer, and the removal rate is more than 99%.
(c) Passing a sufficient amount of the eluent from the column in (a) through the layer of the adsorption equilibrium chelate resin at a flow rate from top to bottom.
(d) And (c) after the elution is balanced, determining the elution rate, wherein the elution rate is more than 99.9 percent. I.e. the resin has been regenerated.
Preferably, the eluent is a sulfuric acid solution, and the concentration range of the eluent is 1-5 mol/L, preferably 3 mol/L.
Compared with the prior art, the invention has the following advantages:
1. the chelating resin contains carboxyl and hydroxyl, can perform coordination and chelation on metal ions by utilizing an O atom, forms a complex with a higher stability constant with certain metals, has higher adsorption selectivity, and plays an important role in the fields of metal ion-containing wastewater treatment, water purification and the like;
2. carboxyl and hydroxyl are introduced into the resin structure, and the O atom can play a role in coordination and chelation on metal ions, so that the bonding force with a target object is stronger, the selectivity is higher, and the resin is more suitable for adsorption of substances at low concentration;
3. the chelating resin can effectively remove various metal impurities in the wastewater, can be used under different acidity conditions, has high elution rate and can be repeatedly used;
4. the chelating resin product has good quality and high added value, can effectively remove metal impurities such as nickel, cobalt, manganese, calcium, magnesium, iron, zinc, copper and the like in wastewater with different acidity, and has a removal rate of more than 99% under a neutral condition;
5. the invention has simple synthesis, easy control of conditions and easy realization of industrial production
6. The raw materials of the 2, 4-dihydroxy phenyl carboxylic acid compound and the chloromethylated bead used in the invention are cheap and easy to obtain;
7. the invention can be used for purifying water or treating wastewater containing metal ions.
Detailed Description
The following examples are given to illustrate the present invention, and the following examples are carried out on the premise of the technical solution of the present invention, and give detailed embodiments and specific procedures, but the scope of the present invention is not limited to the following examples.
In the following examples, unless otherwise specified, all the conventional commercially available raw materials or conventional processing techniques in the art are indicated.
2, 4-dihydroxy benzoic acid is used as a raw material, and the influence of a solvent on the grafting rate is examined:
comparative example 1
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 200mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of dichloromethane for 12 hours. Then, 10.00g of methyl 2, 4-dihydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.2g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were performed for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxybenzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxybenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxybenzoic acid chelate resin, namely the novel chelate resin.
Comparative example 2
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 250mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of acetone for 12 hours. Then, 10.00g of methyl 2, 4-dihydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.20g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were performed for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxybenzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxybenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxybenzoic acid chelate resin, namely the novel chelate resin.
Comparative example 3
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 250mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of chlorine balls were added and the mixture was fully swollen with 100mL of 1, 4-dioxane for 12 hours. Then, 10.00g of methyl 2, 4-dihydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.2g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were performed for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxybenzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxybenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxybenzoic acid chelate resin, namely the novel chelate resin.
Comparative example 4
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 250mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of toluene for 12 hours. Then, 10.00g of methyl 2, 4-dihydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.2g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were performed for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxybenzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxybenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxybenzoic acid chelate resin, namely the novel chelate resin.
Comparative example 5
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 250mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of ethanol for 12 hours. Then, 10.00g of methyl 2, 4-dihydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.2g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were performed for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxyphenylmethyl acetate resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxyphenylacetate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added to the mixture, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxyphenylacetic acid chelate resin, namely the novel chelate resin.
The influence of the reaction time on the grafting yield was investigated:
comparative example 6
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 250mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of acetone for 12 hours. Then, 10.00g of methyl 2, 4-dihydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.2g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were carried out for 24 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxybenzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxybenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxybenzoic acid chelate resin, namely the novel chelate resin.
The influence of the reaction temperature on the grafting ratio was examined:
comparative example 7
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 250mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of acetone for 12 hours. Then, 10.00g of methyl 2, 4-dihydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.2g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were performed for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxybenzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxybenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added, followed by reaction at 80 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxybenzoic acid chelate resin, namely the novel chelate resin.
Investigating the influence of the feeding ratio on the grafting ratio:
comparative example 8
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 250mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of acetone for 12 hours. Then, 7.56g of methyl 2, 4-dihydroxybenzoate, 4.15g of anhydrous potassium carbonate, 0.2g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added thereto, and heated under reflux for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxybenzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxybenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxybenzoic acid chelate resin, namely the novel chelate resin.
Comparative example 9
A preparation method of o-hydroxybenzoic acid chelate resin comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 250mL three-necked flask, 12.00g of 2, 4-dihydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxybenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of acetone for 12 hours. Then, 15.12g of methyl 2, 4-dihydroxybenzoate, 8.29g of anhydrous potassium carbonate, 0.2g of potassium iodide, and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were performed for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxybenzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxybenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxybenzoic acid chelate resin, namely the novel chelate resin.
And (3) testing: full switching capacity test
The purpose of the full exchange capacity test is to obtain the hydrogen ion exchange capacity of the resin by a back titration method, and the hydrogen ion exchange capacity represents the number of hydroxyl groups and carboxyl groups on the resin.
Two portions of the novel chelate resin, each 0.9-1.1g (to an accuracy of 0.0001g), are weighed by a subtractive method on an analytical balance and placed in a dry triangular flask with a stopper. To each triangular flask containing the sample, 100mL of 0.1mol/L sodium hydroxide standard solution was added by a pipette, shaken well, and the stopper was closed tightly. Soaking in 60 deg.C water bath for 2 hr, taking out, and cooling to room temperature. Using a pipette, 25mL of the infusion solution (resin pellet not aspirated) was removed from the Erlenmeyer flask with a stopper, placed in the Erlenmeyer flask, and 50mL of pure water and 3 drops of mixing indicator were added. Titrating to reddish with 0.1mol/L hydrochloric acid standard solution, keeping the reddish color for 15 seconds, and performing a blank experiment.
In the formula: q is the resin total exchange capacity, mmol/g;
CHCl-concentration of hydrochloric acid standard solution, mol/L;
V2-blank experiment consumes volume of hydrochloric acid standard solution, mL;
V1-titrating the volume of the hydrochloric acid standard solution consumed by the soak solution, mL;
m1mass of resin sample, g.
The capacities of the chelate resins of comparative examples 1 to 9 were measured according to the above-mentioned methods as follows:
TABLE 1 exchange Capacity of comparative examples
It can be known that when acetone is used as a solvent to swell the chlorine ball, the performance of the product chelating resin is optimal.
Acetone is taken as a solvent for swelling chlorine spheres, and 2, 4-dihydroxy phenyl carboxylic acid compounds except 2, 4-dihydroxy benzoic acid are taken as raw materials to prepare the chelate resin as follows:
example 1
A preparation method of 2-hydroxy-6-methyl benzoic acid chelating resin (R group is methyl) comprises the following steps:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 200mL three-necked flask, 12.00g of 2, 4-dihydroxy-6-methylbenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxy-6-methylbenzoate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of acetone for 12 hours. Then, 10.92g of methyl 2, 4-dihydroxy-6-methylbenzoate, 6.22g of anhydrous potassium carbonate, 0.20g of potassium iodide and 1 drop of tetrabutylammonium chloride were added in this order, and heating and refluxing were carried out for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the 2-hydroxy-6 methyl-benzoic acid methyl ester resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl 2-hydroxy-6-methylbenzoate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added to react at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin with water, adding excessive 2mol/L sulfuric acid for acidification, fully stirring the mixture at room temperature, washing the mixture to be neutral with a large amount of water, performing suction filtration, and performing vacuum drying on the mixture to obtain the 2-hydroxy-6-methylbenzoic acid chelate resin, namely the novel chelate resin.
Example 2
Preparation method of 2-hydroxymethyl benzoic acid chelating resin (R)1Radical CH2OH) comprising the steps of:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 200mL three-necked flask, 12.00g of 2-hydroxymethyl-4-hydroxybenzoic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2-hydroxymethyl-4-hydroxybenzoate as a white solid. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of acetone for 12 hours. Then, 10.92g of methyl 2-hydroxymethyl-4-hydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.20g of potassium iodide and 1 drop of tetrabutylammonium chloride were sequentially added, and heating and refluxing were carried out for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the 2-hydroxymethyl methyl benzoate resin. And (5) standby. (4) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl 2-hydroxymethylbenzoate resin and 100mL of 2mol/L sodium hydroxide solution were added and reacted at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the 2-hydroxymethyl benzoic acid chelate resin, namely the novel chelate resin.
Example 3
Preparation method (R) of o-hydroxyphenylacetic acid chelate resin2Radical CH2COOH) comprising the steps of:
(1) pretreatment: 30g of chlorine balls (the degree of crosslinking is 4%) and 100mL of deionized water are added to a 250mL beaker, the mixture is stirred at room temperature, the washing is repeated for 3 times, then the filtration is carried out, 100mL of absolute ethyl alcohol is added, the stirring is carried out, and the washing is repeated for 3 times. And performing suction filtration to obtain clean chlorine balls for later use. (2) Esterification reaction: in a 200mL three-necked flask, 12.00g of 2, 4-dihydroxybenzeneacetic acid, 60mL of methanol, and 5mL of sulfuric acid were added, and the mixture was refluxed for 20 hours. After the reaction was completed, it was cooled to room temperature, methanol was removed under reduced pressure, and the residue was poured into 200mL of ice water. The precipitate was collected and washed with water. The solid was recrystallized (methanol/hexane) to give methyl 2, 4-dihydroxyacetate as a white solid product. (3) And (3) substitution reaction: in a 250mL three-necked flask, 30g of a chlorine ball was added, and the mixture was sufficiently swollen with 100mL of acetone for 12 hours. Then, 10.92g of methyl 2, 4-dihydroxybenzoate, 6.22g of anhydrous potassium carbonate, 0.20g of potassium iodide, and 1 drop of tetrabutylammonium chloride were added in this order, and the mixture was refluxed for 12 hours. And separating the resin after the reaction is finished, repeatedly washing the resin by using absolute ethyl alcohol and acetone, then adding 50mL of 2mol/L sulfuric acid solution, fully stirring the mixture at room temperature, then washing the mixture by using excessive 0.246mol/L NaOH solution, washing the mixture to be neutral by using deionized water, performing suction filtration, and drying the mixture in vacuum to constant weight to obtain the o-hydroxyphenylmethyl acetate resin. And (5) standby. (4) And (3) hydrolysis reaction: in a 250mL three-necked flask, 35g of methyl o-hydroxyphenylacetate resin was added, and 100mL of a 2mol/L sodium hydroxide solution was added to the mixture, followed by reaction at 50 ℃ for 12 hours. And separating the resin after the reaction is finished, repeatedly washing with water, then adding excessive 2mol/L sulfuric acid for acidification, fully stirring at room temperature, then washing with a large amount of water to be neutral, performing suction filtration, and performing vacuum drying to constant weight to obtain the o-hydroxyphenylacetic acid chelate resin, namely the novel chelate resin.
The capacities of the chelating resins of examples 1-3 were obtained using the same full exchange capacity test method as follows:
TABLE 2 exchange Capacity of the examples
Example 4
An application of o-hydroxybenzoic acid chelate resin in adsorbing metal ions is as follows:
the o-hydroxybenzoic acid chelate resin prepared in comparative example 2 was selected to adsorb metal ions, and solutions of different acidity were prepared, and the content of metal ions in the solution was as shown in table 3 below.
TABLE 3 ion content in various solutions of different acidity
Preparing 20g of o-hydroxybenzoic acid chelate resin into Na type, placing the Na type into a 150mL conical flask, adding 50mL of the solution, and oscillating the solution in a constant temperature oscillator at 25 ℃ at a rate of 250r/min for 24 hours to ensure that the adsorption reaches the balance (primary adsorption); filtering, and adding 20g Na-type o-hydroxybenzoic acid chelate resin into the filtrate again for adsorption (secondary adsorption) under the same conditions. The concentration of metal ions in the solution at the time of two equilibria was measured and the adsorption rate was calculated.
TABLE 4 ion content of various solutions of different acidity after resin adsorption
The experimental results are shown in table 4, the secondary adsorption rates of the o-hydroxybenzoic acid chelate resin to nickel, cobalt, manganese, calcium, magnesium, iron, zinc and copper are all more than 99%, the advanced treatment of metal ions with different acidity (pH 2-6) is realized, and the o-hydroxybenzoic acid chelate resin can be used for purifying water or treating wastewater containing metal ions.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.