CN110844964B

CN110844964B - Application of green modified carbon nano material in adsorption of organic pollutants in water

Info

Publication number: CN110844964B
Application number: CN201910842241.3A
Authority: CN
Inventors: 王凡凡; 魏源; 赵晓丽; 吴丰昌
Original assignee: Chinese Research Academy of Environmental Sciences
Current assignee: Chinese Research Academy of Environmental Sciences
Priority date: 2018-12-07
Filing date: 2018-12-07
Publication date: 2020-11-10
Anticipated expiration: 2038-12-07
Also published as: CN109678140B; CN109678140A; CN110844964A

Abstract

The invention belongs to the field of nano materials, and particularly relates to an application of a green modified carbon nano material in adsorption of organic pollutants in water. The nano material is prepared from Graphene Oxide (GO) and nano iron, the preparation method comprises the steps of graphene oxide colloid preparation, reduction, drying, detection and the like, and the used reducing agent nano iron has the characteristics of large specific surface area, strong reduction and the like. The method overcomes the defects that the existing reduction technology has certain toxicity and no pertinence in a reduction path, the carbon nano material is easy to agglomerate and is unstable after reduction, and the like, is a technology which is green and mild, is simple to prepare and low in cost, and the converted graphene oxide has good water phase stability and can be used for water phase adsorption; the reduced graphene is a green modified carbon nano material and has good adsorption performance on organic matters.

Description

Application of green modified carbon nano material in adsorption of organic pollutants in water

The invention relates to a divisional application of 'green modified carbon nano material, a preparation method and application thereof', which is applied for application number 201811496359.7, application date 2018, 12 months and 07 days.

Technical Field

The invention belongs to the field of nano materials, and particularly relates to a green modified carbon nano material as well as a preparation method and application thereof.

Background

Carbon nanomaterials have shown great potential for use in many fields due to their excellent electronic, mechanical, optical and catalytic properties. Among them, graphene oxide nanoparticles (GO) are very easily dispersed in aqueous solutions to form colloidal nanoparticles (gopps) due to the surface rich in a large number of oxygen-containing functional groups (such as carboxyl groups, hydroxyl groups, etc.) and have high reactivity, and thus become one of the hottest materials in the scientific community in recent years. The rapid development of the carbon nanomaterial industry has resulted in the inevitable release of carbon nanomaterials into the environment.

Under normal environmental conditions, GO is considered a metastable material, but in the presence of UV radiation, inorganic and organic reducing agents, GO produces a series of reduction reactions: chen et al have shown that sulfur-containing compounds cause GO to undergo reduction when heated to 95 deg.C; chandra et al have shown that hydrazine hydrate can reduce GO to Reduced Graphene Oxide (RGO) when the temperature reaches 90 ℃. These conversion processes can significantly change the physical state and surface chemical properties of the carbon nanomaterial, thereby possibly changing the enrichment capacity of the carbon nanomaterial on toxic pollutants, and also changing the environmental effects and environmental risks of the nanomaterial itself. Research has shown that RGO has strong adsorption affinity to environment-related organic pollutants, and thus, RGO can be used as a carrier of environmental pollutants and greatly improve the migration capacity of pollutants and change the bioavailability thereof.

The reducing agents currently used commercially to produce RGO are mainly vitamin C, hydrazine hydrate, sodium borohydride, hydroquinone, etc., and in order to achieve the desired reduction effect in a short period of time (1 minute to 3 days), it is usually necessary to add heat, ultrasound, a specific pH and H₂O₂And the like, as an external auxiliary condition. Without any auxiliary conditions in the natural environment, the reduction or conversion of GO generally occurs naturally as a buildup over time, but the rate of reaction may be quite slow.

In the existing research, the research related to chemical transformation of GO uses stronger reducing agents, such as hydrazine hydrate, sodium borohydride, hydroquinone and the like, and the reduction process needs to be carried out under the external conditions of heating, ultraviolet irradiation and the like. The addition of trace toxic substances as reducing agents can produce certain harmful effects, and particularly has obvious harmful effects on the relevant fields of biology. Meanwhile, the currently used reduction conversion method has no pertinence to the removal of oxygen-containing functional groups on the surface of GO, the reduction path is uncertain, and after reduction, pi-pi action between GO layers is increased due to the great reduction of the oxygen-containing functional groups to generate irreversible agglomeration, so that the dispersion performance is greatly reduced, and the processability is weakened.

Therefore, while the reaction time is ensured to be shortened as much as possible, it is necessary to develop a means for performing targeted reduction and conversion on different oxygen-containing functional groups on the surface of the carbon nano material under a mild environmental condition or by using a mild reducing agent, so that the environmental effect of the carbon nano material can be improved, and the dispersion stability of the material can also be ensured. And the organic carbon nano-particles are used for adsorbing and degrading organic pollutants in a water environment, so that the migration capacity of the pollutants is improved, and the bioavailability is changed, which has important significance for relieving the problem of water environment pollution.

Disclosure of Invention

In order to solve the technical problems that the existing reduction technology has certain toxicity and no toxicity, the carbon nano material is easy to agglomerate and unstable after reduction, and the like, the modified carbon nano material and the preparation method thereof are green and mild, simple in preparation process and low in cost.

In order to achieve the purpose, the invention adopts the following technical scheme:

a modified carbon nano material is prepared from the following components: graphene oxide, humic acid and ferrous sulfate, or graphene oxide and nano-iron.

Preferably, the dosage ratio of the ferrous sulfate or the nano-iron to the graphene oxide is 0.05-3 mmol/L: 10mg/L, and the mass ratio of the humic acid to the graphene oxide is 0.5-1: 1.

A preparation method of a modified carbon nano material comprises the following steps:

(1) taking graphene oxide, performing ultrasonic treatment in deionized water to obtain colloidal graphene oxide, and refrigerating for storage;

(2) adding the colloidal graphene oxide into a sealed container, introducing nitrogen, adding a nano iron or ferrous sulfate reducing agent, and balancing in a dark place to obtain reduced graphene oxide, wherein the product is for later use; wherein, adding humic acid into a system of ferrous sulfate;

(3) and (3) collecting the product in the step (2), cleaning and drying to obtain the modified nano material.

Preferably, in the step (1), the concentration of the colloidal graphene oxide is 100-500 mg/L.

Preferably, in step (1), the temperature for preservation is 1-5 ℃.

Preferably, the ultrasonic condition in the step (1) is 800-1200HZ, 200-600W, the ultrasonic time is 1-5h, and the ultrasonic temperature is 25-30 ℃.

Preferably, the nitrogen gas is introduced in the step (2) for 10-120min, the rotating speed of the rotary mixer is 5-15rpm, the light-shielding time is 1-3d, and the temperature is 15-30 ℃.

Preferably, the drying temperature in step (3) is 25 ℃.

The invention also aims to provide application of the modified carbon nanomaterial or the nanomaterial prepared by the preparation method of the modified carbon nanomaterial in adsorption or degradation of organic pollutants in water.

Preferably, the organic contaminant in the water is naphthol.

The conception of the invention is as follows:

(1) the nano iron can be used as a reducing agent to modify the carbon nano material graphene oxide, the modification conditions are green and mild, high temperature and high pressure or other chemical reagents are not needed, and the nano iron has a high specific surface area, so that the reduction speed is high. The reduced material still has better stability and can be used for the subsequent water environment.

(2) In the adsorption process after the nano iron is reduced and modified with the graphene oxide, compared with GO, Fe-GO shows stronger adsorption capacity, and the adsorption capacity of the Fe-GO is increased along with the increase of the reduction degree of the GO. Research has shown that the adsorption capacity between naphthol and carbonaceous material in water environment system depends mainly onRelying on pi-pi interactions and hydrogen bonding. The reduction of nano-iron leads the change of GO surface property to change the pi-pi action and hydrogen bond action between GO and naphthol. Firstly, the locally restored pi conjugated region of GO enables the naphthol molecules to be connected with the graphitized structure of GO through the pi-pi action. Secondly, the reduction of nano-iron leads to the reduction of C-O-C (epoxy group), C-OH (hydroxyl group) and C ═ O (carbonyl) on the GO surface, while the increase of COOH (carboxyl group) leads to the stronger capability of forming hydrogen bonds compared with the much reduced C-O (alkoxy group and epoxy group), which also leads to the enhancement of the hydrogen bonding between naphthol and Fe-GO although the oxygen-containing functional groups on the GO surface are reduced totally after the reduction. In addition, the enhanced hydrophobicity of Fe-GO also promotes the adsorption between GO and naphthol, naphthol (log K)_OW2.85) are hydrophobic organic contaminants.

(3) In addition, in the reducing agent ferrous sulfate (Fe)²⁺) In the preparation process of the modified carbon nano material, humic acid, graphene oxide and Fe²⁺The three have a certain synergistic effect, and the addition of humic acid can promote the change of the properties of the graphene oxide on one hand, so that the Fe is promoted²⁺Reducing graphene oxide; humic acid and Fe on the other hand²⁺The complexation between the Fe and the Fe can also improve²⁺The reaction activity is improved, so that the reduction of the graphene oxide is promoted.

(4) In the process of degrading pollutants, the graphene oxide is used as an oxidant to remove Fe in ferrous sulfate²⁺Conversion to Fe³⁺Further degrading or coupling pollutants, wherein the addition of humic acid plays a role in coordination with the Fe²⁺Or Fe³⁺Complexing, and improving the reactivity of metal ions.

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

1) the invention provides a green, mild and targeted means for reducing and converting different oxygen-containing functional groups of a carbon nano material.

2) Simple preparation process, environmental protection and low cost. The reduction and conversion process does not need a complex treatment process, the raw materials do not relate to heavy toxic substances, any toxic substances are not consumed in the conversion process, other toxic and harmful substances are not introduced, and the method is environment-friendly. And the main raw materials used in the preparation process are inorganic salts which are common in the environment, so the cost is very low.

3) The reduction process is targeted, and a proper reducing agent metering can be selected according to the requirements of the target adsorbate. The nano-iron reducing agent selected in the invention can be used for converting different oxygen-containing functional groups of the carbon nano-material, and the nano-iron as the reducing agent has the advantages of larger specific surface area and stronger reduction performance than that of ferrous salt under the same reduction condition.

4) The water stability of the graphene oxide converted by the nano iron reducing agent is still good, and the graphene oxide can be used for water phase adsorption. Most of the existing reduction methods cause GO to generate agglomeration, the dispersity is poor, and a system using water as a solvent cannot be formed. When the sample subjected to reduction and conversion of the nano iron is used as an adsorbent, the dosage is small, and the adsorption efficiency is high. A small amount of samples can be used as an adsorbent to adsorb a large amount of pollutants, and the adsorption coefficient is 10-100 times of that of a common geological adsorbent (such as natural organic matters and clay minerals) in the environment.

5) The sample which is reduced and converted by ferrous sulfate and humic acid generate better complexing effect, and the humic acid and Fe²⁺By complexation of Fe²⁺Activity, and further promoting the degradation of organic matters.

6) The product obtained by reducing graphene oxide with nano iron and the product obtained by complexing humic acid after reducing graphene oxide with ferrous sulfate can play a good role in the adsorption and degradation of organic matters in sewage by the combined use of the two product systems, and the novel green modified nano material is a better sewage treatment agent.

Drawings

FIG. 1: fourier infrared (FTIR) spectra of GO and examples 2-6 nano iron-GO;

FIG. 2: adsorption isotherms of 1-naphthol on GO (a) and nano-iron-GO of examples 2-4 (B-D); q (mmol/kg) and C_W(mmol/L) represents adsorption respectivelyEquilibrium concentration of proton in the adsorbent and aqueous solution;

FIG. 3: example 1, GO, Fe²⁺HA and comparative examples 1-3, HPLC chromatograms of 1-naphthol in seven systems, wherein 5.5min is the liquid chromatogram peak position of 1-naphthol itself;

FIG. 4: and the LC-MS content comparison chart of the 1-naphthol degradation product in different systems.

The invention will now be further illustrated with reference to the accompanying drawings and examples:

Detailed Description

Example 1

(1) Preparing graphene oxide in a colloidal state: taking 0.3g of GO powder, putting the GO powder into 1L of deionized water (DI water) solution, performing ultrasonic treatment for 4h (more than 1h of ultrasonic treatment time, ice blocks need to be added to maintain the temperature of ultrasonic water bath stable) at 1200HZ, 600W and 30 ℃ to obtain a uniform dark brown solution, namely colloidal graphene oxide stock Solution (GONPs), and storing the solution in a refrigerator at 4 ℃.

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 0.417g of ferrous sulfate (crystal, the same below) reducing agent, adding 0.21g of humic acid, and balancing the mixture on a rotary mixer at the speed of 8rmp and the temperature of 25 ℃ in a dark place for 2d to obtain a reduced graphene oxide product;

(3) and (3) collecting the reduced graphene oxide product in the step (2) by using a filter flask, repeatedly washing by using deionized water, and drying the washed sample at 25 ℃ to obtain a powdery product.

Example 2

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 0.084g of nano-iron reducing agent, and balancing the mixture on a rotary mixer at the speed of 8rmp and the temperature of 25 ℃ in a dark place for 2d to obtain a reduced graphene oxide product;

Example 3

(1) Preparing graphene oxide in a colloidal state: 0.1g of GO powder is put into 0.5L of deionized water (DI water) solution and subjected to ultrasonic treatment for 1h at 800HZ, 200W and 30 ℃ to obtain uniform dark brown solution, namely colloidal graphene oxide stock Solution (GONPs), and the dark brown solution is stored in a refrigerator at 1 ℃.

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 10min, adding 0.056g of nano-iron reducing agent, and balancing the mixture on a rotary mixer at the speed of 5rpm and the temperature of 15 ℃ in a dark place for 1d to obtain a reduced graphene oxide product;

(3) and (3) collecting the reduced graphene oxide product in the step (2) by using a filter flask, repeatedly washing the reduced graphene oxide product with deionized water, and drying the washed sample at 25 ℃ to obtain a powdery product.

Example 4

(1) Preparing graphene oxide in a colloidal state: loading 0.5g of GO powder in 2L of deionized water (DI water) solution at 1200HZ and 600W, performing ultrasonic treatment at 25 ℃ for 5h (more than 1h of ultrasonic treatment time, ice blocks need to be added to maintain the temperature of the ultrasonic water bath stable), obtaining uniform dark brown solution, namely colloidal graphene oxide stock Solution (GONPs), and storing the solution in a refrigerator at 5 ℃.

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 120min, adding 1.4g of a nano-iron reducing agent, and balancing the mixture on a rotary mixer at a speed of 15rpm and a temperature of 30 ℃ in a dark place for 3d to obtain a reduced graphene oxide product;

Example 5

(1) Preparing graphene oxide in a colloidal state: 0.3g of GO powder is put into 1L of deionized water (DI water) solution to be subjected to ultrasonic treatment for 4h at 1200HZ, 600W and 28 ℃ (ice blocks need to be added for more than 1h to maintain the temperature of ultrasonic water bath stable), so as to obtain uniform dark brown solution, namely colloidal graphene oxide stock Solution (GONPs), and the uniform dark brown solution is stored in a refrigerator at 4 ℃.

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 1.68g of a nano-iron reducing agent, and balancing the mixture on a rotary mixer at a speed of 8rmp and a temperature of 25 ℃ in a dark place for 2d to obtain a reduced graphene oxide product;

Example 6

(1) Preparing graphene oxide in a colloidal state: taking 0.3g of GO powder, performing ultrasonic treatment in 1L of deionized water (DI water) solution at 1200HZ, 600W and 25 ℃ for 4h (ice blocks need to be added for more than 1h of ultrasonic treatment time to maintain the temperature of the ultrasonic water bath stable), obtaining a uniform dark brown solution, namely colloidal graphene oxide stock Solution (GONPs), and storing the solution in a refrigerator at 4 ℃.

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 5.04g of a nano iron reducing agent, and balancing the mixture on a rotary mixer at the speed of 8rmp and the temperature of 25 ℃ in a dark place for 2d to obtain a reduced graphene oxide product;

Example 7

(1) Preparing graphene oxide in a colloidal state: taking 0.5g of GO powder, putting the GO powder into 1L of deionized water (DI water) solution, performing ultrasonic treatment for 4h (more than 1h of ultrasonic treatment time, ice blocks need to be added to maintain the temperature of ultrasonic water bath stable) at 1200HZ, 600W and 30 ℃ to obtain a uniform dark brown solution, namely colloidal graphene oxide stock Solution (GONPs), and storing the solution in a refrigerator at 4 ℃.

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 6.95g of ferrous sulfate reducing agent, adding 0.25g of humic acid, and balancing the mixture on a rotary mixer at the speed of 8rmp and in a dark place at 25 ℃ for 2d to obtain a reduced graphene oxide product;

Example 8

(1) Preparing graphene oxide in a colloidal state: taking 0.1g of GO powder, putting the GO powder into 1L of deionized water (DI water) solution, performing ultrasonic treatment for 4h (more than 1h of ultrasonic treatment time, ice blocks need to be added to maintain the temperature of ultrasonic water bath stable) at 1200HZ, 600W and 30 ℃ to obtain a uniform dark brown solution, namely colloidal graphene oxide stock Solution (GONPs), and storing the solution in a refrigerator at 4 ℃.

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 8.34g of ferrous sulfate reducing agent, adding 0.1g of humic acid, and balancing the mixture on a rotary mixer at the speed of 8rmp and in a dark place at the temperature of 25 ℃ for 2d to obtain a reduced graphene oxide product;

Comparative example 1 (without ferrous sulfate compared to example 1)

(graphene oxide + humic acid, Fe-free)²⁺)

(1) Preparing graphene oxide in a colloidal state: and (3) putting 0.3g of GO powder in 1L of deionized water (DI water) solution, performing ultrasonic treatment for 4 hours at 1200HZ, 600W and 30 ℃ to obtain uniform dark brown solution, namely colloidal graphene oxide stock Solution (GONPs), and storing the solution in a refrigerator at 4 ℃.

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 0.21g of humic acid, and balancing the mixture on a rotary mixer at the speed of 8rmp and in the dark at the temperature of 25 ℃ for 2 d.

Comparative example 2 (in comparison with example 1, without humic acid)

(graphene oxide + Fe)²⁺Without humic acid)

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 0.417g of ferrous sulfate reducing agent, and balancing the mixture on a rotary mixer at the speed of 8rmp and the temperature of 25 ℃ in a dark place for 2d to obtain a reduced graphene oxide product;

Comparative example 3 (No graphene oxide compared to example 1)

(humic acid + Fe)²⁺And does not contain graphene oxide

(1) 0.21g of humic acid was added to 0.417g of ferrous sulfate and mixed. The mixture was purged with nitrogen and equilibrated on a rotary mixer at 8rmp for 2d at 25 ℃ in the absence of light

COMPARATIVE EXAMPLE 4 (replacement of ferrous sulfate by ferric sulfate compared to EXAMPLE 1)

(graphene oxide + humic acid + Fe)³⁺)

(2) Adding the colloidal graphene oxide into a sealed cylinder bottle, introducing nitrogen for 30min, adding 0.6g of ferric sulfate and 0.21g of humic acid, and balancing the mixture on a rotary mixer at the speed of 8rmp and the temperature of 25 ℃ in a dark place for 2d to obtain a reduced graphene oxide product;

Structural characterization

(1) Surface element composition test:

XPS test: the surface physicochemical properties of GO and the samples of the nano iron-GO in the examples 2-6 are characterized by X-ray photoelectron spectroscopy. The reducing agent reduces the GO to reduce the oxygen-containing functional groups on the surface of GO on the whole, but the specific change of the functional groups is different: the reduction of nano-iron leads to the specific change of oxygen-containing functional groups on the GO surface into epoxy/hydroxyl groups, the reduction of carbonyl groups, but the increase of carboxyl groups.

The results show that compared with the common reduction conversion method, the reduction means selected in the invention can convert different oxygen-containing functional groups on the surface of GO (Table 1).

TABLE 1 carbon-containing species and contents of GO and nano-iron-GO

^aThe values in parentheses are the concentration of nano-iron (mM-nano-iron/(10 mg/L of GO));

^banalyzing by using an X-ray photoelectron spectrometer;

ND: not detected.

(2) Measuring infrared transmission spectrograms of GO and the nano iron-GO samples of examples 2-6, qualitatively distinguishing the types of oxygen-containing functional groups on the surface of the graphene oxide, and using spectral pure potassium bromide and a product in a weight ratio of 1: 80, mixing, drying, uniformly grinding, tabletting and putting into a sample pool to scan an infrared transmission spectrogram of a sample;

the results show that the test results of the infrared spectrometer on GO and the nano iron-GO samples of examples 2-6 are consistent with the XPS results. As shown in FTIR spectrum (figure 1), aromatic carbon increases (C-C/C ═ C vibration peak position is-1730 cm) for nano iron-GO^-1) Reduced epoxy group (C-O-C vibration peak at 1220 cm)^-1) And phenolic hydroxyl (O-H vibration peak located at-1380 cm)^-1) Reduced carbonyl group/carboxyl group (C ═ O vibration peak at 1730 cm)^-1) All are reduced.

Application Effect examples

1. Experimental group of 1-naphthol adsorption experiments on the adsorption performance of organic matters: graphene Oxide (GO) groups and examples 2-4

10mM phosphate buffer (NaH) was used₂PO₄/Na₂HPO₄) The solution pH was controlled to neutral conditions. The EPA bottle with the mixture of the adsorbent (GO or the example 2-4) and the adsorbate (1-naphthol) is covered with a bottle cap and put on a rotary mixer to be balanced for 2 days at room temperature and at the speed of 8rmp in the dark. The equilibrium aqueous phase concentration of contaminant 1-naphthol in the adsorbent GO or samples from examples 2-4 was determined by the fiber solid phase microextraction method: after equilibrium of adsorption on GONPs was reached, a 5cm fiber (fiber) was added to the sample vial. After the bottle cap is closed, the mixture is put on a rotary mixer and is turned to the fiber adsorption equilibrium in a dark place at the room temperature and the speed of 8rmp, and the fiber equilibrium time of the adsorbate is 4 days. Finally, the fiber was taken out, wiped clean with a wet paper towel, and then the adsorbate adsorbed on the fiber was extracted with methanol. The adsorbate concentration in the aqueous phase was calculated by the fiber-water partition coefficient. The concentration of the adsorbate phase on the ginps is calculated by mass balance. All adsorption experiments were performed in parallel at two points.

Detecting the content of 1-naphthol by using an HPLC detection method: the samples were analyzed by Waters high performance liquid chromatography equipped with a 3mm x 100mm SunAire C18 reverse phase column using an ultraviolet detector for 1-naphthol, with a mobile phase ratio of water: methanol (50:50v: v, 1mL/min), ultraviolet detection wavelength 328 nm. The mobile phase ratio, flow rate and detector wavelength are determined based on the observed peak shape, detector response and correlation of the calibration curve.

The results show (fig. 2): the adsorbents of examples 2-4 adsorbed 1-naphthol much more than the GO group.

2. 1-Naphthol degradation test for organic degradation performance

Experimental groups: 1. example 1; 2. examples 7 to 8; 3. graphene oxide; 4. ferrous sulfate; 5. humic acid; 6. ferric sulfate + graphene oxide; 7. ferric sulfate + humic acid; 8. comparative examples 1 to 4.

(1) 10mM phosphate buffer (NaH) was added to the graphene oxide, ferrous sulfate, humic acid, and the samples of example 1 and comparative examples 1-4, respectively₂PO₄And Na₂HPO₄·12H₂O), after adjusting the pH of the whole system to neutral (6.98), 100mg/L of 1-naphthol was added, and then, one 3cm fiber was added to each sample bottle.

(2) After the samples of the examples in (1) were equilibrated on a rotary mixer at a speed of 8rmp for 7 days at 25 ℃ in the absence of light, the fibers were taken out, wiped with a wet paper towel, and the adsorbate adsorbed on the fibers was extracted with 1ml of methanol. The organic substances contained in each experimental group were measured by a combined liquid chromatography-mass spectrometry (LC-MS) technique.

(3) HPLC detection method: the samples were analyzed by Waters high performance liquid chromatography equipped with a 3mm x 100mm SunAire C18 reverse phase column using an ultraviolet detector for 1-naphthol, with a mobile phase ratio of water: methanol (50:50v: v, 1mL/min), ultraviolet detection wavelength 328 nm. The mobile phase ratio, flow rate and detector wavelength are determined based on the observed peak shape, detector response and correlation of the calibration curve.

(4) An LC-MS-MS detection method comprises the following steps: the sample is detected by a liquid chromatography-mass spectrometer (LC-MS-MS, Waters Xevo TQ-S) by adopting a full-scanning m/z of 80-210, a positive ion mode and a dead time of 40 MS.

The experimental result shows that HPLC chromatograms (figure 3) of seven systems of example 1, graphene oxide, ferrous sulfate, humic acid group and comparative examples 1-3 show that only GO and Fe in example 1²⁺1-naphthol is degraded in the coexisting system of the three components (about 8.8min, a degradation product peak appears), and the graphene oxide, the ferrous sulfate and the humic acid group and other six systems of comparative examples 1-3 have no degradation products (only a liquid phase peak of the 1-naphthol exists, about 5.5 min).

Further LC-MS measurement of organic substances contained in different systems showed (FIG. 4), GO and Fe in example 1 and examples 7-8²⁺The content of 1-naphthol degradation products in a coexisting system of HA and the main component is the highest; comparative examples 1-4, the ferric sulfate + graphene oxide system, the ferric sulfate + humic acid system, and the graphene oxide, ferrous sulfate, humic acid system alone had and only had a small amount of degradation products, and were therefore not detected in the HPLC method.

The above detailed description is specific to some possible embodiments of the present invention, and the embodiments are not intended to limit the scope of the present invention, and all equivalent implementations or modifications that do not depart from the scope of the present invention should be included within the scope of the present invention.

Claims

1. The application of the modified carbon nanomaterial in adsorbing organic pollutants in water is characterized in that the modified carbon nanomaterial is prepared from the following components: graphene oxide and nano-iron; the dosage ratio of the nano iron to the graphene oxide is 0.05-3 mmol/L: 10 mg/L;

the preparation method of the modified carbon nano material comprises the following steps:

(2) adding the colloidal graphene oxide into a sealed container, introducing nitrogen, adding nano iron, and balancing in a dark place to obtain reduced graphene oxide, wherein the product is reserved;

2. The application of the modified carbon nanomaterial in adsorbing organic pollutants in water as claimed in claim 1, wherein in the step (1) of the preparation method of the modified carbon nanomaterial, the concentration of the colloidal graphene oxide is 100-500 mg/L.

3. The use of the modified carbon nanomaterial of claim 1 to adsorb organic contaminants in water, wherein the modified carbon nanomaterial is prepared in step (1) at a temperature of 1-5 ℃.

4. The application of the modified carbon nanomaterial in adsorbing organic pollutants in water as claimed in claim 1, wherein in the step (1) of the preparation method of the modified carbon nanomaterial, the ultrasonic condition is 800-1200HZ and 200-600W, the ultrasonic time is 1-5h, and the ultrasonic temperature is 25-30 ℃.

5. The use of the modified carbon nanomaterial of claim 1 to adsorb organic pollutants in water, wherein in the step (2) of the preparation method of the modified carbon nanomaterial, the nitrogen gas is introduced for 10-120 min.

6. The use of the modified carbon nanomaterial in adsorbing organic pollutants in water according to claim 1, wherein in the step (2) of the preparation method of the modified carbon nanomaterial, the light-shielding equilibration is performed on a rotary mixer, the rotating speed of the rotary mixer is 5-15rpm, and the light-shielding time is 1-3 days.

7. The use of the modified carbon nanomaterial of claim 6 to adsorb organic contaminants in water, wherein the organic contaminants in water are naphthols.