A method for preparing aminated magnetic chitosan

Abstract

A method for preparing aminated magnetic chitosan is disclosed. The method includes covering magnetic nanoparticles with chitosan to prepare magnetic chitosan which can be separated in a magnetic manner; forming a polydopamine modification layer on the surface of the magnetic chitosan by utilizing adhesive force of the polydopamine; and then performing addition and condensation to graft polyethyleneimine to the magnetic chitosan surface modified with the polydopamine to obtain the aminated magnetic chitosan. The prepared aminated magnetic chitosan has higher adsorption performance and adsorption selectivity for cadmium in water, can achieve rapid magnetic separation, can be recycled and reused, and solves a problem that conventional ion exchange, precipitation and other unit techniques don't have ideal cleaning effects. The method has mild reaction conditions, and can avoid environment pollution caused by organic solvents, reaction conditions and a modification process are easy to control and the method is suitable for industrial production.

Description

technical field

[0001] The invention relates to the technical field of metal-organic composite materials, in particular to a preparation method of aminated magnetic chitosan. Background technique

[0002] Chitosan (CTS) is one of the most effective adsorbents for the removal of heavy metal ions and has been widely used in the treatment of wastewater and soil contaminated by heavy metals. Chitosan molecules contain a large number of amino groups and hydroxyl groups, which can effectively physically or chemically adsorb heavy metal ions through hydrogen bonds, salt bonds, and chelation. However, due to the shortcomings of chitosan itself, such as easy swelling, soluble in dilute acid, poor mechanical properties, etc., it is difficult to be directly applied to the removal of heavy metal pollution in wastewater, and chitosan generally requires physical or Chemical modification to overcome its deficiencies.

[0003] Dopamine is a kind of neurotransmitter, which can undergo self...

Examples

Embodiment 1

[0029] A preparation method of aminated magnetic chitosan, comprising the following steps;

[0030] 1) Preparation of magnetic nanoparticles: add 25mL water into a 50mL three-neck flask, stir mechanically, pass argon gas to remove oxygen for about 30min, add 4mmol FeCl 3 ·6H 2 O and 2.4 mmol FeSO 4 ·7H 2 O, continue to stir for 10min, the stirring speed is 500r / min, the solution is orange-red, the water bath is heated to 60°C, slowly add 2.5mL concentrated ammonia water dropwise, and the addition is completed in about 1min. The orange red turns black, continue to stir for 40 minutes, raise the temperature to 80°C, stop stirring, and age for 30 minutes, in order to prevent Fe 2+ was oxidized, and the solution was kept under the protection of argon during the whole reaction process. The magnetic nanoparticles were separated by an external magnetic field, then washed three times alternately with deionized water and alcohol, and the product was freeze-dried and stored for late...

Embodiment 2

[0035] A preparation method of aminated magnetic chitosan, comprising the following steps;

[0036] 1) Preparation of magnetic nanoparticles: add 25mL water into a 50mL three-neck flask, stir mechanically, pass argon gas to remove oxygen for about 30min, add 5mmol FeCl3 6H2O and 2.1mmol FeSO4 7H2O, continue stirring for 10min, the stirring speed is 500r / min, the solution is Orange red, heat the water bath to 60°C, slowly add 2.5mL of concentrated ammonia water dropwise, and finish adding in about 1 minute. The pH value of the solution is between 9-10, and the solution quickly changes from orange red to black. ℃, stop stirring, and age for 30 minutes, in order to prevent Fe 2+ was oxidized, and the solution was kept under the protection of argon during the whole reaction process. The magnetic nanoparticles were separated by an external magnetic field, then washed three times alternately with deionized water and alcohol, and the product was freeze-dried and stored for later use...

Embodiment 3

[0045] The aminated magnetic chitosan prepared in Example 1 is the test group, and the magnetic chitosan prepared in Example 2, Comparative Example 1, and Comparative Example 2 is a control group 1, a control group 2, and a control group 3, and each group is tested The adsorption time and adsorption capacity when the adsorption of Cd(II) solution reaches adsorption equilibrium are shown in Table 1.

[0046] Test method: take Cd(NO 3 ) 2 4H 2 O was dissolved in 500mL deionized water to prepare a mother solution with a concentration of Cd(II) of 1000mg / L. The Cd(II) solutions of various concentrations required in the experiment were obtained by diluting the mother solution. 20 mL of Cd(II) solution with a concentration of 200 mg / L was placed in a 100 mL Erlenmeyer flask, and each group of samples with a dose of 5-20 mg was added respectively.

[0047] The Erlenmeyer flask containing the test solution was placed in a shaker at a rotational speed of 150 rpm. After the adsorptio...

technical field

[0001] The invention relates to the technical field of metal-organic composite materials, in particular to a preparation method of aminated magnetic chitosan. Background technique

[0002] Chitosan (CTS) is one of the most effective adsorbents for the removal of heavy metal ions and has been widely used in the treatment of wastewater and soil contaminated by heavy metals. Chitosan molecules contain a large number of amino groups and hydroxyl groups, which can effectively physically or chemically adsorb heavy metal ions through hydrogen bonds, salt bonds, and chelation. However, due to the shortcomings of chitosan itself, such as easy swelling, soluble in dilute acid, poor mechanical properties, etc., it is difficult to be directly applied to the removal of heavy metal pollution in wastewater, and chitosan generally requires physical or Chemical modification to overcome its deficiencies.

[0003] Dopamine is a kind of neurotransmitter, which can undergo self...

Examples

Embodiment 1

[0029] A preparation method of aminated magnetic chitosan, comprising the following steps;

[0030] 1) Preparation of magnetic nanoparticles: add 25mL water into a 50mL three-neck flask, stir mechanically, pass argon gas to remove oxygen for about 30min, add 4mmol FeCl 3 ·6H 2 O and 2.4 mmol FeSO 4 ·7H 2 O, continue to stir for 10min, the stirring speed is 500r / min, the solution is orange-red, the water bath is heated to 60°C, slowly add 2.5mL concentrated ammonia water dropwise, and the addition is completed in about 1min. The orange red turns black, continue to stir for 40 minutes, raise the temperature to 80°C, stop stirring, and age for 30 minutes, in order to prevent Fe 2+ was oxidized, and the solution was kept under the protection of argon during the whole reaction process. The magnetic nanoparticles were separated by an external magnetic field, then washed three times alternately with deionized water and alcohol, and the product was freeze-dried and stored for late...

Embodiment 2

[0035] A preparation method of aminated magnetic chitosan, comprising the following steps;

[0036] 1) Preparation of magnetic nanoparticles: add 25mL water into a 50mL three-neck flask, stir mechanically, pass argon gas to remove oxygen for about 30min, add 5mmol FeCl3 6H2O and 2.1mmol FeSO4 7H2O, continue stirring for 10min, the stirring speed is 500r / min, the solution is Orange red, heat the water bath to 60°C, slowly add 2.5mL of concentrated ammonia water dropwise, and finish adding in about 1 minute. The pH value of the solution is between 9-10, and the solution quickly changes from orange red to black. ℃, stop stirring, and age for 30 minutes, in order to prevent Fe 2+ was oxidized, and the solution was kept under the protection of argon during the whole reaction process. The magnetic nanoparticles were separated by an external magnetic field, then washed three times alternately with deionized water and alcohol, and the product was freeze-dried and stored for later use...

Embodiment 3

[0045] The aminated magnetic chitosan prepared in Example 1 is the test group, and the magnetic chitosan prepared in Example 2, Comparative Example 1, and Comparative Example 2 is a control group 1, a control group 2, and a control group 3, and each group is tested The adsorption time and adsorption capacity when the adsorption of Cd(II) solution reaches adsorption equilibrium are shown in Table 1.

[0046] Test method: take Cd(NO 3 ) 2 4H 2 O was dissolved in 500mL deionized water to prepare a mother solution with a concentration of Cd(II) of 1000mg / L. The Cd(II) solutions of various concentrations required in the experiment were obtained by diluting the mother solution. 20 mL of Cd(II) solution with a concentration of 200 mg / L was placed in a 100 mL Erlenmeyer flask, and each group of samples with a dose of 5-20 mg was added respectively.

[0047] The Erlenmeyer flask containing the test solution was placed in a shaker at a rotational speed of 150 rpm. After the adsorptio...

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