A method for quantitative prediction of electronic transfer ability of dissolvable carbon black

Abstract

The application discloses a kind of solubility carbon black electron transfer capacity quantitative prediction method, more than three temperature is selected and is prepared carbon black using biomass, is configured into mixed solution by adding water, mixed solution is cultured by shaker, solution is centrifuged, supernatant is filtered, and solubility carbon black solution is obtained;The concentration of solubility carbon black solution is determined, and the cyclic voltammetry curve of carbon black solution is determined using electrochemical workstation and three electrode system, the peak potential corresponding to each scanning speed in the curve, peak current are obtained, according to scanning rate, peak potential, peak current, solubility carbon black solution concentration, electron transfer rate constant k 0 It is calculated by using Bulter-Volmer equation, linear prediction model is constructed by the logarithmic value of electron transfer rate constant k 0 And pyrolysis temperature, the electron transfer capacity of carbon black at different temperatures is predicted using the model;The method is simple and easy to operate, and the electron transfer capacity of solubility carbon black of known raw material type can be directly predicted.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of solubility carbon black electron transfer ability quantitative prediction method, belong to solubility carbon black and electron transfer technical field. BACKGROUND

[0002] Carbon black is discharged into the atmosphere by fossil fuel, biofuel and biomass insufficient combustion, solubility carbon black is the water-soluble part of carbon black widely exists in natural water body, can account for 10% of total dissolved organic carbon in river water, and its biogeochemical cycle process has important significance to water environment.

[0003] Recently, it is found that the surface functional group of solubility carbon black can reversibly accept and provide a large number of electrons, and the role in many biogeochemical cycles and environment-related redox processes is very similar to natural organic matter, although it has been proposed that the electron transfer can be quantitatively described by electrochemical means, but the quantitative prediction method of electron transfer ability of solubility carbon black at any pyrolysis temperature within a certain range has not been established. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a simple, intuitive and rapid evaluation method for predicting the electron transfer ability of solubility carbon black prepared from known raw materials and pyrolysis temperature.

[0005] The technical scheme of the present application is as follows:

[0006] A quantitative prediction method of solubility carbon black electron transfer ability, the specific steps are as follows:

[0007] (1) Preparation of carbon black: carbon black is prepared by programmed temperature rise, and carbon black is prepared by selecting three or more temperatures and biomass;

[0008] (2) Extraction of solubility carbon black: the above mixture is placed in a shaking bed and cultured in the dark, the obtained solution is centrifuged in a centrifuge, and the supernatant obtained after centrifugation is filtered through a filter membrane to obtain a solubility carbon black solution;

[0009] (3) Using total organic carbon analyzer, the total organic carbon content of solubility carbon black solution is determined; gel permeation chromatography is used to determine the average relative molecular mass of solubility carbon black, and the concentration of solubility carbon black solution is calculated;

[0010] (4) Using a three-electrode system, Ag / AgCl electrode, platinum wire and glassy carbon electrode as reference electrode, counter electrode and working electrode respectively, adding soluble carbon black solution in the electrochemical cell, connecting the electrochemical workstation, setting potential, scan rate, scan number, sampling interval, standing time, changing scan rate, obtaining a set of cyclic voltammograms, peak current and potential due to oxidation and reduction reaction caused by the highest current characterizing direct electron transfer and charge and discharge process;

[0011] According to the scan rate, peak potential, peak current concentration of soluble carbon black solution, the electron transfer rate constant k 0 is calculated by using Bulter-Volmer equation

[0012]

[0013] In the formula: Intercept overpotential and linear fitting intercept of peak current natural logarithm value at different scan rates;

[0014] n is the number of transferred electrons, which is 2;

[0015] F is Faraday's constant;

[0016] A is the surface area of the working electrode, unit is m 2 ;

[0017] C is the concentration of soluble carbon black solution, mol / L;

[0018] e is the natural constant, the same throughout the text;

[0019] k 0 is used to quantify the electron transfer ability of soluble carbon black;

[0020] (6) By using origin software to fit the logarithmic value of electron transfer rate constant k 0 and pyrolysis temperature, a linear prediction model is constructed, and this model is used to predict the electron transfer ability of carbon black at different temperatures.

[0021] Step (1) The ratio of ultrapure water and carbon black is 40:1-100:1 (v / m).

[0022] Step (2) The shaking bed temperature is 20-30℃, the shaking time is 12-48h, and the speed is 100-200rpm.

[0023] Step (2) The centrifugation time is 5-15min, and the centrifuge speed is 2000-3000r / min.

[0024] Step (4) The scan rate setting range is 10-300mv / s, and the voltage setting range is-1.5-1.5V.

[0025] The present application has the advantages of:

[0026] 1、 The present application uses simple electrochemical analysis means, combined with calculation and model, fast and simple.

[0027] 2、 The present application can accurately predict the electron transfer capacity of the soluble carbon black according to the linear model through the type of raw material and the temperature of carbon black. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 lgk for example 1 0 - Linear prediction model curve of pyrolysis temperature;

[0029] Figure 2 lgk for example 2 0 - Linear prediction model curve of pyrolysis temperature;

[0030] Figure 3 k 0 - Pyrolysis temperature histogram. DETAILED DESCRIPTION

[0031] The present application will be further described below in conjunction with specific examples, but the scope of protection of the present application is not limited to the described content.

[0032] Example 1

[0033] A quantitative prediction method of the electron transfer capacity of soluble carbon black, the specific steps are as follows:

[0034] (1) Carbon black preparation: rice straw was heated to 200℃, 300℃, 400℃, 500℃, 600℃ at 20℃ / min under nitrogen atmosphere, and each temperature was kept for 2h, and a group of carbon black was obtained after pyrolysis, and cooled to room temperature;

[0035] (2) Extraction of soluble carbon black: 1g of carbon black was weighed in a 50mL centrifuge tube, 40mL of ultrapure water was added, and after uniform mixing, it was placed in a shaking bed at a temperature of 25℃ and shaken at a speed of 160rpm in the dark for 24h, then centrifuged at a speed of 3000r / min for 10min in a centrifuge, and the supernatant obtained after centrifugation was filtered through a 0.45μm filter membrane to obtain a soluble carbon black solution;

[0036] (3) Total organic carbon test: the concentration of the soluble carbon black solution was adjusted according to the detection limit of the instrument, and the volume of the sample solution was not less than 20mL;

[0037] (4) Average relative molecular mass: the concentration of the soluble carbon black solution obtained in step (3) was obtained by using conventional gel permeation chromatography;

[0038] (5) Cyclic voltammetry test: using a three-electrode system, Ag / AgCl electrode, platinum wire and glassy carbon electrode as reference electrode, counter electrode and working electrode respectively, 10 mL of dissolvable carbon black solution was added into the electrochemical cell, the electrochemical workstation was connected, the potential range was set to-1.5-1.5V, the scanning speed was set to 10mV / s, 20mV / s, 40mV / s, 60mV / s, 80mV / s, 100mV / s, 120mV / s, 140mV / s, 160mV / s in turn, the sampling interval was 0.01V, and the standing time was 30s, a group of cyclic voltammetry curves was obtained, and the peak current and the potential with the highest current due to oxidation and reduction reaction characterized the direct electron transfer and the charging and discharging process;

[0039] (6) Calculation of electron transfer rate constant k 0 : according to the scanning rate, peak potential, peak current and concentration of dissolvable carbon black solution, the electron transfer rate constant k 0 was calculated by using Bulter-Volmer equation:

[0040]

[0041] In the formula: Intercept is the overpotential and the intercept of the linear fitting of the natural logarithm value of the peak current at different scanning speeds;

[0042] n is the number of transferred electrons, which is 2;

[0043] F is the Faraday constant;

[0044] A is the surface area of the working electrode, and the unit is m 2 ;

[0045] C is the concentration of dissolvable carbon black, mol / L;

[0046] The electron transfer capacity of dissolvable carbon black is quantified in this way;

[0047] (7) A linear prediction model was constructed by using the logarithmic value of the electron transfer rate constant k 0 and the pyrolysis temperature, and the electron transfer capacity of carbon black at different temperatures was predicted by using the model.

[0048] Figure 1 The k 0 -PT curve of Example 1 can be seen that the pyrolysis temperature and the electron transfer rate are logarithmically linear, and the fitting curve R 2 =0.98, so according to the fitting equation lgk 0 =0.01448T-2.80, the electron transfer capacity of dissolvable carbon black of rice straw at any temperature in the range of 200-600℃ can be predicted.

[0049] Example 2

[0050] A quantitative prediction method of solubility carbon black electron transfer ability, the specific steps are as follows:

[0051] (1) Carbon black preparation: sawdust is heated to 200℃, 300℃, 400℃, 500℃, 600℃ at 20℃ / min under nitrogen atmosphere respectively, and each temperature is kept for 2h, and a group of carbon black is obtained after pyrolysis, and cooled to room temperature;

[0052] (2) Extraction of solubility carbon black: 1g of carbon black is weighed in a 50mL centrifuge tube, 50mL of ultrapure water is added, and after uniform mixing, it is placed in a shaking bed at a temperature of 20℃ and shaken at a speed of 180rpm in the dark for 24h, and after taking out, it is centrifuged in a centrifuge at a speed of 2500r / min for 5min, and the supernatant obtained after centrifugation is filtered through a 0.45μm filter membrane, and the solubility carbon black solution is obtained;

[0053] (3) Total organic carbon test: the concentration of the solubility carbon black solution is adjusted according to the detection limit of the instrument, and the volume of the sample solution is not less than 20mL;

[0054] (4) Average relative molecular mass: the concentration of the solubility carbon black solution obtained in step (3) is obtained by using conventional gel permeation chromatography;

[0055] (5) Cyclic voltammetry test: using a three-electrode system, Ag / AgCl electrode, platinum wire and glassy carbon electrode are used as reference electrode, counter electrode and working electrode respectively, 9mL of solubility carbon black solution is added in the electrochemical cell, connected to the electrochemical workstation, the potential range is set to-1.5-1.5V, the scanning speed is set to 10mV / s, 20mV / s, 40mV / s, 60mV / s, 80mV / s, 100mV / s, 120mV / s, 140mV / s, 160mV / s in turn, the sampling interval is 0.01V, and the standing time is 30s, a group of cyclic voltammetry curves is obtained, and the peak current and the potential with the highest current due to oxidation and reduction reaction characterize the direct electron transfer and charging and discharging process;

[0056] (6) Calculation of electron transfer rate constant k 0 : according to the scanning rate, peak potential, peak current, solubility carbon black solution concentration, and using Bulter-Volmer equation to calculate the electron transfer rate constant k 0 :

[0057]

[0058] In the formula: Intercept overpotential and the intercept of the linear fitting of the natural logarithm value of the peak current at different scanning speeds;

[0059] n is the number of transferred electrons, which is 2;

[0060] F is Faraday's constant;

[0061] A is the working electrode surface area, in m 2 ;

[0062] C is the concentration of the soluble carbon black, in mol / L;

[0063] The electronic transfer ability of the soluble carbon black is quantified in this way;

[0064] (7) A linear prediction model is constructed by the logarithmic value of the electronic transfer rate constant k 0 and the pyrolysis temperature, and this model is used to predict the electronic transfer ability of carbon black at different temperatures.

[0065] Figure 2 k 0 -PT curves of Example 2, it can be seen that the pyrolysis temperature and the electronic transfer rate are logarithmically linear, and the fitting curve R 2 = 0.91, so according to the fitting equation lgk 0 = 0.00735T-1.68, the electronic transfer ability of the pine sawdust soluble carbon black at any temperature in the range of 200-600℃ can be predicted.

[0066] Figure 3 k 0 - pyrolysis temperature histograms of Examples 1 and 2, it can also be seen that the electronic transfer rate constants k 0 of the carbon black solutions prepared from two kinds of biomass are obviously different.

[0067] Example 3

[0068] A quantitative prediction method for the electronic transfer ability of soluble carbon black, the specific steps are as follows:

[0069] (1) Carbon black preparation: corn straw is heated to 200℃, 400℃ and 600℃ at 20℃ / min under nitrogen atmosphere, respectively, and each temperature is kept for 2h, and a group of carbon black is obtained after pyrolysis, and cooled to room temperature;

[0070] (2) Extraction of soluble carbon black: 1g of carbon black is weighed into a 50mL centrifuge tube, 100mL of ultrapure water is added, and after uniform mixing, it is placed in a shaking bed at a temperature of 30℃ and shaken at a speed of 100rpm in the dark for 48h, and after taking out, it is centrifuged at a speed of 2000r / min in a centrifuge for 15min, and the supernatant obtained after centrifugation is filtered through a 0.45μm filter membrane, and the soluble carbon black solution is obtained;

[0071] (3) Total organic carbon test: the concentration of the soluble carbon black solution is adjusted according to the detection limit of the instrument, and the volume of the sample solution is not less than 20mL;

[0072] (4) Average relative molecular mass: The concentration of the soluble carbon black solution was obtained by conventional gel permeation chromatography in combination with step (3);

[0073] (5) Cyclic voltammetry curve test: A three-electrode system was used, with Ag / AgCl electrode, platinum wire and glassy carbon electrode as reference electrode, counter electrode and working electrode, respectively. 15 mL of dissolved carbon black solution was added to the electrochemical cell and connected to the electrochemical workstation. The potential range was set to -1.5 to 1.5 V, and the scan rate was set to 10 mV / s, 20 mV / s, 40 mV / s, 60 mV / s, 80 mV / s, 100 mV / s, 120 mV / s, 140 mV / s and 160 mV / s respectively. The sampling interval was 0.01 V and the settling time was 30 s. A set of cyclic voltammetry curves were obtained. The peak current and the potential at which the current is highest due to oxidation and reduction reactions characterize the direct electron transfer and charge-discharge process.

[0074] (6) Electron transfer rate constant k 0 Calculation: Based on the scan rate, peak potential, peak current, and concentration of soluble carbon black solution, the electron transport rate constant k is calculated using the Butler-Volmer equation. 0 :

[0075]

[0076] Where: Intercept is the intercept of the natural logarithmic linear fit of the overpotential and the peak current at different scan rates;

[0077] n is the number of electrons transferred, which is 2;

[0078] F is Faraday's constant;

[0079] A represents the surface area of ​​the working electrode, in m². 2 ;

[0080] C represents the concentration of soluble carbon black, in mol / L;

[0081] This is used to quantify the electron transfer capability of soluble carbon black;

[0082] (7) Through the electron transfer rate constant k 0 A linear prediction model was constructed using the logarithmic value and pyrolysis temperature. The pyrolysis temperature and electron transfer rate showed a logarithmic linear relationship, and this model was used to predict the electron transfer capacity of carbon black at different temperatures.

[0083] The above examples illustrate that the electron transfer capability of soluble carbon black is highly dependent on the pyrolysis temperature and the type of raw materials, providing a basis for those skilled in the art to subsequently explain the migration and transformation patterns and biogeochemical cycling behavior of pollutants in the environment.

Claims

1. A method for quantitatively predicting the electron transfer capacity of soluble carbon black, characterized in that, The specific steps are as follows: (1) Carbon black is prepared by selecting three or more temperatures using biomass, and then mixed with ultrapure water to form a mixture; (2) The mixture was cultured in a shaker in the dark, centrifuged, and the supernatant was filtered to obtain a soluble carbon black solution. The concentration of the soluble carbon black solution was then determined. (3) Using an electrochemical workstation and a three-electrode system, the cyclic voltammetry curve of the carbon black solution was measured, and the electron transfer rate constant k was calculated using the Butler-Volmer equation. 0 : Where: Intercept is the intercept of the natural logarithmic linear fit of the overpotential and the peak current at different scan rates; n is the number of electrons transferred, which is 2; F is Faraday's constant; A represents the surface area of ​​the working electrode, in m². 2 ; C represents the concentration of the soluble carbon black solution, in mol / L; Use k 0 To quantify the electron transfer capability of soluble carbon black; (4) Through the electron transfer rate constant k 0 The logarithmic values ​​and pyrolysis temperatures were fitted using Origin software to construct a linear prediction model.

2. The method for quantitatively predicting the electron transfer capacity of soluble carbon black according to claim 1, characterized in that, Step (1) The ratio of ultrapure water to carbon black is 40:1 to 100:1 mL / g.

3. The method for quantitatively predicting the electron transfer capacity of soluble carbon black according to claim 1, characterized in that, Step (2) The temperature of the shaker is 20-30℃, the shaking time is 12-48h, and the speed is 100-200rpm.

4. The method for quantitatively predicting the electron transfer capacity of soluble carbon black according to claim 1, characterized in that, Step (2) The centrifugation time is 5 to 15 minutes and the centrifuge speed is 2000 to 3000 r / min.

5. The method for quantitatively predicting the electron transfer capacity of soluble carbon black according to claim 1, characterized in that, In step (3), the scanning speed for cyclic voltammetry curve determination is 10 mV / s to 300 mV / s, and the voltage is -1.5 to 1.5 V.

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