CN103657614A - Polystyrene based magnetic nano ferroferric oxide arsenic removal composite and preparation method thereof - Google Patents

Abstract

This patent discloses a preparation method of a polystyrene-based magnetic nano-ferric oxide arsenic-removing composite material. In a sealed container, water is used as the reaction solvent, styrene monomer and potassium persulfate are mixed, and the mixture is kept under nitrogen protection for 70 React at ~85°C for 12-24 hours under stirring conditions to obtain polystyrene pellets; in a sealed container, use water as the reaction solvent, bubble nitrogen to remove oxygen, and then add FeSO ₄ .7H ₂ O and FeCl ₃ .6H ₂ O, slowly add ammonia water dropwise under stirring conditions until the pH value reaches 8, stop the dropwise addition, react under stirring conditions at 25-40°C for 30-120min, and finally magnetically separate the obtained product, decant and wash several times, and dialyze. The colloid is nano-scale magnetic Fe ₃ O ₄ ; after the nano-scale magnetic Fe ₃ O ₄ colloid is ultrasonically treated, it is added dropwise to polystyrene pellets under stirring conditions, and after stirring heterogeneous coagulation, the resulting product is magnetically separated , decanting and washing several times, that is.

Description

A polystyrene-based magnetic nano-ferric oxide arsenic-removing composite material and its preparation method

technical field

The invention relates to a high-performance environmental functional composite material for adsorbing trace amounts of _AS (V) pollutants in an environmental medium, in particular to a core-shell arsenic-removing composite material with polystyrene as the core and nano-ferric iron tetroxide as the shell.

Background technique

Nano-scale iron oxide Fe ₃ O ₄ has received extensive attention in the treatment of arsenic-containing wastewater because of its strong adsorption capacity for As. In particular, Fe3O4 nanoparticles can be separated from adsorbents under a magnetic field due to their magnetic properties, and there have been many related research works. There are many factors that affect the arsenic adsorption capacity of nano-ferrite oxides, among which the particle size is a very critical factor. Reducing the particle size can increase the adsorption area hundreds to thousands of times and increase the dispersibility in aqueous solution. Some work has evaluated the effect of Fe ₃ O ₄ particle size on the adsorption capacity of arsenic (CYavuz, et.al.Science314 (2006) 964.) found that when the monodisperse Fe ₃ O ₄ particle size is around 25nm, the maximum adsorption capacity is 25mg /g, when the particle size of Fe ₃ O ₄ is reduced to 12nm, the maximum adsorption capacity can reach more than 150mg/g. It can be seen that reducing the particle size is an effective way to increase the adsorption capacity. However, these small-sized adsorption particles may encounter problems when used, because the force of the magnetic field on the particles is proportional to the particle size. When the particle size is too small, it is not enough to overcome the Brownian motion between particles, and magnetic separation cannot be achieved. accomplish. Or a very high magnetic field is required to separate, which will greatly increase the cost. In this way, the stability of the adsorbent in aqueous solution and the ease of separation become a contradiction. It is very important to develop an adsorbent to improve the adsorption capacity of nano-Fe ₃ O ₄ materials for arsenic adsorption while ensuring easy separation in aqueous solution.

Contents of the invention

The technical problem to be solved by the present invention is to provide a polystyrene-based magnetic nano-ferric oxide composite material, which can improve the adsorption capacity of magnetic nano-ferrite particles to adsorb arsenic while maintaining solid-liquid separation, so as to achieve arsenic adsorption in water. efficient removal.

The present invention also provides a preparation method of the above-mentioned polystyrene-based magnetic nano ferric oxide composite material.

In order to solve the problems of the technologies described above, the technical scheme adopted in the present invention is as follows:

A method for preparing a polystyrene-based magnetic nano-ferric oxide arsenic-removing composite material, the method comprising the following steps:

(1) Synthesis of polystyrene pellets: In a sealed container, use water as the reaction solvent, mix styrene monomer and potassium persulfate, and react under inert gas protection, 70-85°C, and stirring for 12-24 hours , to obtain polystyrene pellets;

(2) Synthesis of nano-scale magnetic Fe ₃ O ₄ : In a sealed container, use water as the reaction solvent, bubble through an inert gas to remove oxygen, then add FeSO ₄ .7H ₂ O and FeCl ₃ .6H ₂ O, stirring conditions Slowly add ammonia water dropwise under low temperature until the pH value reaches 8, stop the dropwise addition, react at 25-40°C for 30-120 minutes under stirring conditions, and finally magnetically separate the obtained product, decant and wash several times, and dialyze for 24-48 hours. The colloid is nano-scale magnetic Fe ₃ O ₄ ;

(3) Synthesis of arsenic-removing composite materials: after ultrasonic treatment of the nano-scale magnetic Fe ₃ O ₄ colloid obtained in step (2), add it dropwise to polystyrene pellets under stirring conditions, and stir for 1 to 3 hours to separate the phases After coagulation, the obtained product is magnetically separated, decanted and washed several times to obtain the obtained product.

In step (1), the added mass of potassium persulfate is 0.12-0.5% of the mass of styrene monomer.

In step (1), the stirring speed is 100-200rmp.

In step (2), the reaction molar ratio of FeSO ₄ .7H ₂ O and FeCl ₃ .6H ₂ O is 1:1-1.5.

In step (2), the stirring speed is 200-320rmp.

In step (2), the concentration of ammonia water is 5-15 mol/L.

In step (2), the time for bubbling an inert gas to remove oxygen is preferably 30 to 60 minutes.

In steps (1) and (2), the inert gas is preferably nitrogen.

In steps (1) and (2), water is used as the reaction solvent, and the amount of water used is not particularly regulated, as long as it is enough to dissolve the reaction raw materials and provide a liquid reaction environment.

In step (3), the ultrasonic treatment conditions are power of 70-100w, frequency of 20-60KHZ, and duration of 3-20min.

In step (3), the mass ratio of the polystyrene pellets to the nano-scale magnetic Fe ₃ O ₄ colloid is 1:0.1-0.2.

In step (3), the stirring speed is 300-500rmp.

The polystyrene-based magnetic nanometer iron ferric oxide arsenic-removing composite material prepared by the above method is also within the protection scope of the present invention.

Among them, the prepared polystyrene-based magnetic nano-ferric oxide arsenic removal composite material uses polystyrene beads as the core and nano-scale magnetic Fe ₃ O ₄ as the shell, and the particle size of the polystyrene beads is It is 500nm～2um, and the shell thickness is 20～100nm.

Beneficial effects: the preparation method of the invention has the advantages of simple operation and low cost. The polystyrene-based magnetic nano-ferric oxide arsenic removal composite material prepared by the present invention has the following advantages: 1. The inner core is polystyrene PS microspheres, which greatly improves the strength of the composite material; 2. The surface-loaded The nanoparticles of ferroferric oxide are evenly distributed. Third, the material has a high specific surface area and is evenly dispersed in wastewater; 3. The dispersibility in water has been greatly improved, which enables it to efficiently adsorb and remove As(V) in wastewater. The foundation is laid, so that the material has high arsenic _AS (V) adsorption capacity and good stability, and is easy to recycle by magnetic separation.

Detailed ways

The present invention can be better understood from the following examples. However, those skilled in the art can easily understand that the content described in the embodiments is only for illustrating the present invention, and should not and will not limit the present invention described in the claims.

Example 1:

Synthesis of polystyrene pellets: Seal the reaction vessel, add 100ml of distilled water under nitrogen protection, heat to 70°C, add 1g of styrene monomer, stir at 160rmp, add 2.3mg of potassium persulfate to the reaction system after stirring , and reacted at a constant temperature of 70°C for 12 hours to obtain polystyrene pellets (referred to as PS pellets) with a diameter of 800 nm.

Synthesis of nano-scale magnetic Fe ₃ O ₄ : Seal the reactor, bubble nitrogen gas to deoxygenate for 30min, then add 2.78g (0.01mol) FeSO ₄ .7H ₂ O and 3.244g (0.012mol) FeCl ₃ .6H ₂ O was added to the reactor respectively, and 5mol/L ammonia water was slowly added dropwise under 300rmp mechanical stirring until the pH value reached 8, then the dropwise addition was stopped, and the reaction was continued at a constant temperature of 25°C for 120min. Finally, the obtained product was magnetically separated, decanted, washed several times, and dialyzed for 48 hours. The obtained colloid was Fe ₃ O ₄ with a particle size of 30 nm.

Synthesis of arsenic-removing composite materials: Take 0.2g of Fe ₃ O ₄ nano colloidal particles and place them in an ultrasonic device for 3 minutes, ultrasonic power 100w, frequency 20KHZ, and then under 300rmp mechanical stirring, Fe ₃ O ₄ colloidal liquid drop by drop Add it to 1 g of polystyrene pellets, stir for 1 hour, and finally obtain the product PS-Fe ₃ O ₄ through heterogeneous coagulation.

Ultrasound the prepared PS-Fe ₃ O ₄ for 10min, then add 0.05g sample to each 100ml of As(V) simulated wastewater with a concentration of 50mg/L, put it in a shaker, and absorb it at a constant temperature of 25°C for 24h. The adsorption amount of As(V) was 100 mg/g.

Example 2:

Synthesis of polystyrene pellets: Seal the reaction vessel, add 90ml of distilled water under nitrogen protection, heat to 70°C, add 1g of styrene monomer, stir at 200rmp, add 2.3mg of potassium persulfate to the reaction system after stirring , and reacted at a constant temperature of 70°C for 24 hours to obtain polystyrene pellets (referred to as PS pellets) with a diameter of 500 nm.

Synthesis of nano-scale magnetic Fe ₃ O ₄ : Seal the reactor, bubble nitrogen to deoxygenate for 30min, then mix 2.78g (0.01mol) FeSO ₄ .7H ₂ O and 3.5165g (0.013mol) FeCl ₃ .6H ₂ O was added to the reactor respectively, and 10 mol/L ammonia water was slowly added dropwise under 320rmp mechanical stirring until the pH value reached 8, then the dropwise addition was stopped, and the reaction was continued at a constant temperature of 25°C for 120min, and finally the resulting product was magnetically separated and poured. Filtered and washed several times, and dialyzed for 48 hours, the obtained colloid was Fe ₃ O ₄ with a particle size of 20nm.

Synthesis of arsenic-removing composite materials: Take 0.1g of Fe ₃ O ₄ nano-colloidal particles and put them in an ultrasonic device for 20 minutes, ultrasonic power 90w, frequency 20KHZ, and then under 350rmp mechanical stirring, Fe ₃ O ₄ colloidal liquid drop by drop Add it to 1 g of polystyrene pellets, stir for 3 hours, and finally obtain the product PS-Fe ₃ O ₄ through heterogeneous coagulation.

Ultrasound the prepared PS-Fe ₃ O ₄ for 10min, then add 0.05g sample to each 100ml of As(V) simulated wastewater with a concentration of 50mg/L, put it in a shaker, and absorb it at a constant temperature of 25°C for 24h. The adsorption amount of As(V) was 150 mg/g.

Example 3:

Synthesis of polystyrene pellets: seal the reaction vessel, add 110ml of distilled water under nitrogen protection, heat to 85°C, add 1g of styrene monomer, stir at 100rmp, add 2.8mg of potassium persulfate to the reaction system after stirring , and reacted at a constant temperature of 85°C for 12 hours to obtain polystyrene pellets (referred to as PS pellets) with a size of 2 μm.

Synthesis of nano-scale magnetic Fe ₃ O ₄ : Seal the reactor, bubble nitrogen to remove oxygen for 30min, then add 2.78g (0.01mol) FeSO ₄ .7H ₂ O and 4.0575g (0.015mol) FeCl ₃ .6H ₂ O was added to the reactor respectively, and 15 mol/L ammonia water was slowly added dropwise under 200rmp mechanical stirring until the pH value reached 8, then the dropwise addition was stopped, and the reaction was continued at a constant temperature of 40°C for 30min. Finally, the obtained product was magnetically separated, decanted, washed several times, and dialyzed for 24 hours. The obtained colloid was Fe ₃ O ₄ with a particle size of 100 nm.

Synthesis of arsenic-removing composite materials: Take 0.2g of Fe ₃ O ₄ nano colloidal particles and put them in an ultrasonic device for 20 minutes, ultrasonic power 100w, frequency 60KHZ, then under 300rmp mechanical stirring, Fe ₃ O ₄ colloidal liquid drop by drop Add it to 1 g of polystyrene pellets, stir for 3 hours, and finally obtain the product PS-Fe ₃ O ₄ through heterogeneous coagulation.

Ultrasound the prepared PS-Fe ₃ O ₄ for 10min, then add 0.05g sample to each 100ml of As(V) simulated wastewater with a concentration of 50mg/L, put it in a shaker, and absorb it at a constant temperature of 25°C for 24h. The adsorption amount of As(V) was 80 mg/g.

Example 4:

Synthesis of polystyrene pellets: seal the reaction vessel, add 100ml of distilled water under nitrogen protection, heat to 85°C, add 1g of styrene monomer, stir at 180rmp, add 5mg of potassium persulfate to the reaction system after stirring, The reaction was carried out at a constant temperature of 85° C. for 24 hours to obtain polystyrene pellets (referred to as PS pellets) with a diameter of 700 nm.

Synthesis of nano-scale magnetic Fe ₃ O ₄ : Seal the reactor, bubble nitrogen gas to deoxygenate for 30min, then add 2.78g (0.01mol) FeSO ₄ .7H ₂ O and 3.244g (0.012mol) FeCl ₃ .6H ₂ O was added to the reactor respectively, and 5mol/L ammonia water was slowly added dropwise under mechanical stirring at 250rmp until the pH value reached 8, then the dropwise addition was stopped, and the reaction was continued at a constant temperature of 25°C for 120min. Finally, the obtained product was magnetically separated, poured Filtered and washed several times, and dialyzed for 24 hours, the obtained colloid was Fe ₃ O ₄ with a particle size of 50nm.

Synthesis of arsenic-removing composite materials: Take 0.16g of Fe ₃ O ₄ nano-colloidal particles and put them in an ultrasonic device for 20 minutes, ultrasonic power 100w, frequency 20KHZ, and then under 400rmp mechanical stirring, Fe ₃ O ₄ colloidal liquid drop by drop Add it to 1 g of polystyrene pellets, stir for 3 hours, and finally obtain the product PS-Fe ₃ O ₄ through heterogeneous coagulation.

Ultrasound the prepared PS-Fe ₃ O ₄ for 10min, then add 0.05g sample to each 100ml of As(V) simulated wastewater with a concentration of 50mg/L, put it in a shaker, and absorb it at a constant temperature of 25°C for 24h. The adsorption amount of As(V) was 103 mg/g.

Example 5:

Synthesis of polystyrene pellets: seal the reaction vessel, add 100ml of distilled water under nitrogen protection, heat to 70°C, add 5g of styrene monomer, stir at 180rmp, add 10mg of potassium persulfate to the reaction system after stirring, The reaction was carried out at a constant temperature of 70° C. for 24 hours to obtain polystyrene pellets (referred to as PS pellets) with a diameter of 600 nm.

Synthesis of nano-scale magnetic Fe ₃ O ₄ : Seal the reactor, bubble nitrogen gas to deoxygenate for 30min, then add 2.78g (0.01mol) FeSO ₄ .7H ₂ O and 3.244g (0.012mol) FeCl ₃ .6H ₂ O was added to the reactor respectively, and 10 mol/L ammonia water was slowly added dropwise under 300rmp mechanical stirring until the pH value reached 8, then the dropwise addition was stopped, and the reaction was continued at a constant temperature of 35°C for 120min. Finally, the obtained product was magnetically separated, decanted, washed several times, and dialyzed for 48 hours. The obtained colloid was Fe ₃ O ₄ with a particle size of 35 nm.

Synthesis of arsenic-removing composite materials: Take 0.1g of Fe ₃ O ₄ nano-colloidal particles and put them in an ultrasonic machine for 10 minutes, ultrasonic power 70w, frequency 40KHZ, and then under 350rmp mechanical stirring, Fe ₃ O ₄ colloidal liquid drop by drop Add it to 1 g of polystyrene pellets, stir for 3 hours, and finally obtain the product PS-Fe ₃ O ₄ through heterogeneous coagulation.

Ultrasound the prepared PS-Fe ₃ O ₄ for 10min, then add 0.05g sample to each 100ml of As(V) simulated wastewater with a concentration of 50mg/L, put it in a shaker, and absorb it at a constant temperature of 25°C for 24h. The adsorption amount of As(V) was 120 mg/g.

Embodiment 6:

Synthesis of polystyrene pellets: seal the reaction vessel, add 100ml of distilled water under nitrogen protection, heat to 70°C, add 3g of styrene monomer, stir at 130rmp, add 5mg of potassium persulfate to the reaction system after stirring, The reaction was carried out at a constant temperature of 85° C. for 24 hours to obtain polystyrene pellets (abbreviated as PS pellets) with a size of 1.2 μm.

Synthesis of nano-scale magnetic Fe ₃ O ₄ : Seal the reactor, bubble nitrogen to deoxygenate for 30 min, then add 2.78g (0.01mol) FeSO ₄ .7H ₂ O and 2.705g (0.01mol) FeCl ₃ .6H ₂ O was added to the reactor respectively, and 5mol/L ammonia water was slowly added dropwise under 320rmp mechanical stirring until the pH value reached 8, then the dropwise addition was stopped, and the reaction was continued at a constant temperature of 35°C for 60min. Finally, the obtained product was magnetically separated, decanted, washed several times, and dialyzed for 48 hours. The obtained colloid was Fe ₃ O ₄ with a particle size of 25 nm.

Synthesis of arsenic-removing composite materials: Take 0.125g of Fe ₃ O ₄ nano-colloidal particles and place them in an ultrasonic device for 10 minutes, ultrasonic power 100w, frequency 40KHZ, and then under 350rmp mechanical stirring, Fe ₃ O ₄ colloidal liquid drop by drop Add it to 1 g of polystyrene pellets, stir for 3 hours, and finally obtain the product PS-Fe ₃ O ₄ through heterogeneous coagulation.

Ultrasound the prepared PS-Fe ₃ O ₄ for 10min, then add 0.05g sample to each 100ml of As(V) simulated wastewater with a concentration of 50mg/L, put it in a shaker, and absorb it at a constant temperature of 25°C for 24h. The adsorption amount of As(V) was 86 mg/g.

Embodiment 7:

Synthesis of polystyrene pellets: Seal the reaction vessel, add 100ml of distilled water under nitrogen protection, heat to 70°C, add 3g of styrene monomer, stir at 140rmp, add 6.8mg of potassium persulfate to the reaction system after stirring , and reacted at a constant temperature of 70°C for 12 hours to obtain polystyrene pellets (referred to as PS pellets) with a size of 1.0 μm.

Synthesis of nano-scale magnetic Fe ₃ O ₄ : Seal the reactor, bubble nitrogen gas to deoxygenate for 30min, then add 2.78g (0.01mol) FeSO ₄ .7H ₂ O and 3.244g (0.012mol) FeCl ₃ .6H ₂ O was added to the reactor respectively, and 15 mol/L ammonia water was slowly added dropwise under 270rmp mechanical stirring until the pH value reached 8, then the dropwise addition was stopped, and the reaction was continued at a constant temperature of 30°C for 120min. Finally, the obtained product was magnetically separated, decanted, washed several times, and dialyzed for 48 hours. The obtained colloid was Fe ₃ O ₄ with a particle size of 40 nm.

Synthesis of arsenic-removing composite materials: Take 0.2g of Fe ₃ O ₄ nano-colloidal particles and put them in an ultrasonic device for 10 minutes, ultrasonic power 80w, frequency 60KHZ, and then under 350rmp mechanical stirring, Fe ₃ O ₄ colloidal liquid drop by drop Add it to 1 g of polystyrene pellets, stir for 3 hours, and finally obtain the product PS-Fe ₃ O ₄ through heterogeneous coagulation.

Ultrasound the prepared PS-Fe ₃ O ₄ for 10min, then add 0.05g sample to each 100ml of As(V) simulated wastewater with a concentration of 50mg/L, put it in a shaker, and absorb it at a constant temperature of 25°C for 24h. The adsorption amount of As(V) was 90 mg/g.

Embodiment 8:

Synthesis of polystyrene pellets: seal the reaction vessel, add 100ml of distilled water under nitrogen protection, heat to 70°C, add 2g of styrene monomer, stir at 190rmp, add 3mg of potassium persulfate to the reaction system after stirring, The reaction was carried out at a constant temperature of 70° C. for 24 hours to obtain polystyrene pellets (referred to as PS pellets) with a diameter of 560 nm.

Synthesis of nano-scale magnetic Fe ₃ O ₄ : Seal the reactor, bubble nitrogen gas to deoxygenate for 30min, then add 2.78g (0.01mol) FeSO ₄ .7H ₂ O and 3.244g (0.012mol) FeCl ₃ .6H ₂ O was added to the reactor respectively, and 10 mol/L ammonia water was slowly added dropwise under 300rmp mechanical stirring until the pH value reached 8, then the dropwise addition was stopped, and the reaction was continued at a constant temperature of 25°C for 100min. Finally, the obtained product was magnetically separated, decanted, washed several times, and dialyzed for 36 hours. The obtained colloid was Fe ₃ O ₄ with a particle size of 32 nm.

Synthesis of arsenic-removing composite materials: Take 0.1g of Fe ₃ O ₄ nano-colloidal particles and put them in an ultrasonicator for 5 minutes, ultrasonic power 100w, frequency 50KHZ, and then under 330rmp mechanical stirring, Fe ₃ O ₄ colloidal liquid drop by drop Add it to 1 g of polystyrene pellets, stir for 3 hours, and finally obtain the product PS-Fe ₃ O ₄ through heterogeneous coagulation.

Ultrasound the prepared PS-Fe ₃ O ₄ for 10min, then add 0.05g sample to each 100ml of As(V) simulated wastewater with a concentration of 50mg/L, put it in a shaker, and absorb it at a constant temperature of 25°C for 24h. The adsorption amount of As(V) was 132 mg/g.

Claims (11)

1. a preparation method for polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite, is characterized in that, the method comprises the steps:

(1) polystyrene sphere is synthetic: in airtight container, take water as reaction dissolvent, styrene monomer and potassium peroxydisulfate are mixed, under inert gas shielding, 70～85 ℃, stirring condition, react 12～24h, obtain polystyrene sphere;

(2) nano-scale magnetic Fe ₃o ₄synthetic: in airtight container, take water as reaction dissolvent, bubbling leads to inert gas deoxygenation, then adds FeSO ₄.7H ₂o and FeCl ₃.6H ₂o, slowly drips ammoniacal liquor under stirring condition until pH value to 8 stops dripping, and under 25～40 ℃, stirring condition, reacts 30～120min, and finally that the product magnetic of gained is separated, decantation is cleaned for several times, the 24～48h that dialyses, and the colloid of gained is nano-scale magnetic Fe ₃o ₄;

(3) arsenic removal composite is synthetic: the nano-scale magnetic Fe that step (2) is obtained ₃o ₄after the ultrasonic processing of colloid, under stirring condition, drop in polystyrene sphere, stir after the cohesion of 1～3h out-phase, the product magnetic of gained is separated, incline to considering and clean for several times, obtain.

2. the preparation method of polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite according to claim 1, is characterized in that, in step (1), the quality that adds of potassium peroxydisulfate is 0.12～0.5% of styrene monomer quality.

3. the preparation method of polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite according to claim 1, is characterized in that, in step (1), mixing speed is 100～200rmp.

4. the preparation method of polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite according to claim 1, is characterized in that, in step (2), and FeSO ₄.7H ₂o and FeCl ₃.6H ₂the reaction mol ratio of O is 1:1～1.5.

5. the preparation method of polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite according to claim 1, is characterized in that, in step (2), mixing speed is 200～320rmp.

6. the preparation method of polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite according to claim 1, is characterized in that, in step (2), the concentration of ammoniacal liquor is 5～15mol/L.

7. the preparation method of polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite according to claim 1, is characterized in that, in step (3), ultrasonic treatment conditions are power 70～100w, frequency 20～60KHZ, and the duration is 3～20min.

8. the preparation method of polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite according to claim 1, is characterized in that, in step (3), and polystyrene sphere and nano-scale magnetic Fe ₃o ₄the mass ratio of colloid is 1:0.1～0.2.

9. the preparation method of polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite according to claim 1, is characterized in that, in step (3), mixing speed is 300～500rmp.

10. the polystyrene base magnetic nano tri-iron tetroxide arsenic removal composite that in claim 1～9, any one prepares.

11. polystyrene base magnetic nano tri-iron tetroxide arsenic removal composites according to claim 10, it take polystyrene sphere as core, with nano-scale magnetic Fe ₃o ₄for shell, polystyrene sphere particle diameter is 500nm～2um, and shell thickness is 20～100nm.