CN107894405B - Method for determining nutrients in soil - Google Patents
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- CN107894405B CN107894405B CN201711400166.2A CN201711400166A CN107894405B CN 107894405 B CN107894405 B CN 107894405B CN 201711400166 A CN201711400166 A CN 201711400166A CN 107894405 B CN107894405 B CN 107894405B
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Abstract
The invention discloses a method for determining nutrients in soil, which comprises the following steps of: sampling soil to a depth of 0.5-1.5 m; preparing liquid: taking 10 parts of sieved soil by mass, adding 80-100 parts of deionized water, adding 2-3 parts of leaching agent, stirring at a high speed of 2000-3000r/min for 10-20min, and then stirring at a rotating speed of 40-60r/min for hydration; standing: placing the mixed solution obtained in the step A2 in an environment with the temperature of 30-40 ℃ and standing for 2-3 h; separation: inserting two electrode plates into the mixed liquid, inputting steep pulse current to the two electrode plates, setting the peak value of the steep pulse at 180V (150 plus one), the pulse width at 0.5-0.8ms, the repetition frequency at 300kHz (200 plus one), and the pulse gradient at 50-100 ns; centrifuging: placing the separation liquid obtained in the step A4 in a centrifuge, and centrifuging at the rotating speed of 10000-; and (3) determination: after centrifugation, the supernatant was aspirated, and the nutrients in the supernatant were measured using an ultraviolet-visible spectrophotometer. When the method is used for measuring the nutrient ions in the soil, the measured data is more accurate, and the measuring efficiency is higher.
Description
Technical Field
The invention relates to the technical field of soil detection, in particular to a method for determining nutrients in soil.
Background
The vegetation is an indicator of the natural environment around the people, and the research of the vegetation is one of the important means for revealing the natural law. The existence of any plant community is closely related to the environments such as altitude, climate, hydrology, terrain, soil and the like. The vegetation characteristics and the relationship between the vegetation characteristics and the environment are one of the core problems of vegetation ecology research, and the relationship between plant community distribution, species composition, diversity and environmental factors is three important aspects of the research on the relationship between vegetation and the environment. The research on the relation between vegetation and environment in foreign countries is always in the leading position, a large number of models are established and applied to research the relation between vegetation and environment, the researches provide important references for human to understand the response of vegetation to climate change, and the researches are particularly important today when the global climate change is aggravated.
The research on vegetation characteristics and environmental relationships in China is in contradiction between lack and urgent practical needs. At present, natural vegetation protection and management, water and soil loss, land desertification, grassland degradation and management and protection, biodiversity protection and vegetation restoration in China have no knowledge of the relationship between vegetation and environment which is not required to be applied. As a country lacking natural vegetation, any improper management, development and utilization will have serious consequences in china. Therefore, only by clearly knowing the relationship between the distributed plant community structure, species composition and diversity and environmental factors, a corresponding reasonable protection strategy can be made.
Any plant grows by taking soil as attachment and directly obtains nutrient components and water from the soil, so that research and analysis on soil components of the environment where the vegetation is located plays an important role in researching the vegetation, and when the research and analysis on the nutrient components in the soil are carried out, the current method basically comprises the following steps: the soil sample is subjected to pretreatment processes such as drying, grinding, sieving, leaching, diluting, developing and the like to prepare a solution to be detected, and then the content of each ion in the solution to be detected is measured by using an ultraviolet-visible spectrophotometer or atomic absorption spectrophotometry; however, the nutrient content of the soil sample may change along with the evaporation of soil moisture in the air drying process, and the measurement reliability of the soil sample is difficult to guarantee due to the influence of environmental factors such as temperature, microbial activity and the like.
Disclosure of Invention
In view of the above, the present invention provides a method for determining nutrients in soil, which can determine nutrient ions in soil more accurately and more efficiently.
The invention solves the technical problems by the following technical means:
a method for determining nutrients in soil comprises the following steps,
a1, sampling: removing a 2-3cm surface layer on the soil surface, then sampling the soil from top to bottom, and sampling the soil to a depth of 0.5-1.5 m;
a2, liquid preparation: crushing the soil sampled in the step A1, stirring and mixing uniformly, screening impurities by using a 50-80-mesh screen, taking 10 parts of screened soil by mass, adding 80-100 parts of deionized water, adding 2-3 parts of leaching agent, stirring for 10-20min under the high-speed stirring of 2000-3000r/min, stirring at the rotating speed of 40-60r/min, and hydrating for 1-2h to obtain a mixed solution;
a3, standing: placing the mixed solution obtained in the step A2 in an environment with the temperature of 30-40 ℃ and standing for 2-3 h;
a4, separation: inserting two electrode plates into the mixed liquid under stirring at a rotating speed of 40-60r/min, inputting steep pulse current to the two electrode plates, setting the peak value of the steep pulse at 180V, the pulse width at 0.5-0.8ms, the repetition frequency at 300kHz and the pulse gradient at 50-100 ns;
a5, centrifugation: after 10-15min of steep pulse separation, placing the separation liquid obtained in the step A4 in a centrifuge within 60-80 seconds, and centrifuging at the rotating speed of 10000-;
a6, measurement: after centrifugation, the supernatant was aspirated, and the nutrients in the supernatant were measured using an ultraviolet-visible spectrophotometer.
The principle of the invention is as follows: in the step A1, the soil surface has more humus, the soil layer covers less roots of plants, the plants cannot be supplied with nutrients at any time during the growth of the plants, and the soil layer needs to be rotten and permeated for a period of time before being absorbed by the plants, so that when the soil nutrients are measured, the soil nutrients are removed, the soil nutrients supplied to the plants are measured more accurately, and when the soil is sampled, the measured data is that the whole soil is 0.5-1.5 meters deep soilThe average value of the nutrients of the soil section is more accurate, and the nutrients in the soil where the plants grow can be reflected; in the step 2, the soil has some larger impurities such as stones, sticks and the like, the nutrients in the soil are dissolved in the solution conveniently after the soil is crushed, the impurities are filtered by using a screen, the soil is dispersed in deionized water, and the leaching agent is added to dissolve calcium, phosphorus, aluminum, iron, magnesium and NH in the soil4 +、K+The leaching agent is used for leaching various components in the soil, the soil is stirred by using a stirrer rotating at a high speed, the soil can be scattered into tiny particles by using stirring force generated during high-speed stirring during stirring, various ionic components in the soil can be conveniently immersed into the solution, and in addition, a part of ions adsorbed on the soil can be thrown into the solution by using huge centrifugal force generated during high-speed stirring, so that the leaching effect of various ions in the soil is better, and the measured nutrient data is more accurate; in the step A3, the mixed solution is kept stand, so that the soil can be statically hydrated in the solution, and in the hydration process, nutrient ions in the soil are extracted by the extracting agent; in the step A4, steep pulse positioning current is used, and a pulse time-varying electric field generated by the steep pulse current enables a time-varying potential difference to be generated in the mixed solution, so that the movement rate of nutrient ions in the mixed solution is accelerated and the difference is time-varying, therefore, the separation of colloid particle impurities and nutrient ions in soil can be realized, the nutrient ions in the soil are separated from the adsorption of the colloid particle impurities, more of the colloid particle impurities are dissolved in the solution, and then the colloid particle impurities are complexed and chelated by an extracting agent, so that the determination of the soil nutrient ions is more accurate; in step a5, the purpose of centrifugation is to separate the solution and the soil solids in the mixed solution into layers, so that all nutrient ions in the soil are dissolved in the solution, and the various nutrient ions in the solution can be measured according to the prior art of step a 6.
Further, the leaching agent comprises NaHCO3Ethylenediaminetetraacetic acid and NaF. Among them, HC03 -Effective Ca and P in the calcareous soil can be effectively extracted; NaHCO 23Has alkalinity, and can extract effective Fe-P and part of effective Fe-PAl-P；F-Is a heavy metal complexing agent, has the strongest complexing ability on Al, is a strong extractant of A1-P, and simultaneously can be used for treating Fe2+Also has certain complexing ability; the ethylene diamine tetraacetic acid is used as a metal chelating agent, and can chelate metal ions from Fe-P, Al-P and Ca-P with surface activity, so that effective solid-phase active phosphorus in the solution enters the solution and is extracted; na in the leaching agent+Has certain substitution ability, and can extract substituted potassium in soil; due to ethylene diamine tetraacetic acid and F-The chelation and complexation of the metal elements are performed, so that effective Cu, Fe, Mn and Zn in the soil are extracted simultaneously; NH adsorbed on soil colloid4 +、K+、Ca2+And Mg2+The equicationic is in Na+The substitution of (a) partially into solution.
Further, the NaHCO is used according to parts by mass3The weight portion of the NaF is 2-3, the concentration is 0.1-0.3moL/L, the weight portion of the ethylene diamine tetraacetic acid is 4-6, the concentration is 0.01-0.015moL/L, the weight portion of the NaF is 5-7, and the concentration is 0.01-0.015 moL/L. Experiments prove that the extraction effect of nutrient ions dissolved in the solution is better and the measured concentration of the nutrient ions is more accurate due to the proportioning concentration in the leaching agent.
Further, the steep pulse current is an exponential decay pulse current. The exponentially decaying pulse current can be obtained by charging and discharging the energy storage capacitor, and the pulse system is simple in design and manufacture, wide in output voltage range and more convenient to operate.
Furthermore, the anode of the electrode plate is a carbon nano tube electrode, the cathode of the electrode plate is a copper mesh electrode, and the distance between the electrode plates is 3-5 cm. The carbon nanotube electrode and the copper mesh electrode have good conductivity, can promote electron transfer, improve the impurity rate of colloid particles separated from nutrient ions, have large specific surface area and more active sites, can improve the performance of the electrode, can change the resistance between the electrodes at the distance between the polar plates, and have higher current efficiency and smaller electrolysis energy consumption when the distance between the polar plates is 3-4 cm.
The cathode is an electrode modified to a copper mesh by ordered mesoporous carbon-chitosan, the anode is a multiwall carbon nanotube modified by β -cyclodextrin, the copper mesh electrode is modified by ordered mesoporous carbon-chitosan, the ordered mesoporous carbon has good conductivity, can promote electron transfer, and further improves the rate of nutrient ions to be separated from colloid particle impurities, and the chitosan can greatly improve the selectivity and sensitivity of electrode reaction, and the multiwall carbon nanotube is modified by β -cyclodextrin, so that the modified electrode has the advantages of good selectivity, high sensitivity, good electrochemical stability, strong anti-interference capability and the like, and shows excellent conductivity.
Further, the manufacturing method of the electrode plate cathode comprises the following steps: comprises the following steps of (a) carrying out,
b1 polishing copper mesh by polishing copper mesh electrode with effective diameter of 10-12cm on chamois leather with particle size of 0.05-0.2 μm α -A1203Polishing the powder into a mirror surface;
b2, cleaning: cleaning the copper mesh electrode by using deionized water, and respectively carrying out ultrasonic oscillation cleaning for 15min in acetone, absolute ethyl alcohol and water to obtain a clean and bright copper mesh electrode;
b3, weighing ordered mesoporous carbon which accounts for 10-20% of the total mass of the copper mesh electrode, and a chitosan solution which accounts for 80-90% of the total mass of the copper mesh electrode and has a concentration of 0.5%, dissolving the ordered mesoporous carbon in the chitosan solution, and performing ultrasonic dispersion for 20-30min to obtain a uniform ordered mesoporous carbon-chitosan dispersion solution;
b4, absorbing the dispersion liquid obtained in the step B3 by using an injector, uniformly dripping the dispersion liquid on the surface of the copper mesh electrode, and drying the electrode for 10-15min under an infrared lamp to obtain the ordered mesoporous carbon-chitosan modified copper mesh electrode.
Further, the manufacturing method of the electrode plate anode comprises the following steps: comprises the following steps of (a) carrying out,
c1, placing carbon nanotube electrode on chamois leather pad, and applying α -A1 with particle size of 0.05-0.2 μm203Polishing by powder;
c2, polishing the carbon nanotube electrode by using HNO3Ultrasonic cleaning with anhydrous ethanol and distilled water for 2-3min, and placing the cleaned carbon nanotube electrode in 0.5mol/L H2S03In solution, at a sweeping rate of 35-50mV/sCircularly scanning the potential range of-0.3 to +1.0V until no peak exists, taking out the carbon nano tube electrode, washing the carbon nano tube electrode with distilled water, and storing the carbon nano tube electrode in the distilled water for later use;
c3, using the carbon nano tube electrode obtained in the step C2 as a substrate electrode, and the thickness of the carbon nano tube electrode is 4.0-5.0 multiplied by 10-3β -cyclodextrin in mol/L and H in 0.5mol/L2S03In a medium, circularly scanning for 20 weeks at a sweeping speed of 80-100mV/s between the potential ranges of-0.6V to 1.2V under the static condition of a solution until a cyclic voltammetry curve is stable, then taking out an electrode, rinsing the surface of the electrode by deionized water, and drying;
c4, HNO in volume ratio3: HCl ═ 1: 3 refluxing for 12h to carboxylate the multi-wall carbon nano-tube, washing the multi-wall carbon nano-tube with 0.01mol/L NaOH until the pH value is 6.5-7.5, centrifuging and drying;
c5, weighing 5 parts by weight of the multi-walled carbon nano-tube treated in the step C4 in 6-8 parts by weight of N, N-methylformamide, and ultrasonically dispersing for 30min to finally obtain stable dispersion liquid;
and C6, taking the dispersed liquid drops obtained in the step C5 by using an injector, modifying the surface of the electrode by β -cyclodextrin in the step C3, and drying under an infrared lamp to obtain the anode of the electrode plate.
The invention has the beneficial effects that:
(1) according to the invention, the nutrient ions in the soil are determined by using the fresh soil, so that the problem that the measurement reliability is difficult to guarantee due to the influence of environmental factors such as temperature and microbial activity in the soil drying process is avoided, and the determined soil nutrient data is more accurate;
(2) NaHCO is used in the invention3Extracting soil with lixiviant comprising EDTA and NaF to obtain soil extract containing calcium, phosphorus, aluminum, iron, magnesium and NH4 +、K+The main components such as Cu, Mn, Zn and the like are extracted into the solution, so that the analysis of each component in the soil is facilitated, and the analysis data of nutrients is accurate and reliable;
(3) the invention uses the steep pulse to position the current, and the pulse time-varying electric field generated by the steep pulse current enables the mixed solution to generate the time-varying potential difference, so that the movement rate of nutrient ions in the mixed solution is accelerated and the time-varying difference between the movement rate and the time-varying difference can be realized, the separation of colloid particle impurities and nutrient ions in the soil can be realized, the nutrient ions in the soil are separated from the adsorption of the colloid particle impurities, more nutrient ions are dissolved in the solution, and the measurement of the soil nutrient ions is more accurate;
(4) the electrode used in the invention is an electrode modified by ordered mesoporous carbon-chitosan to a copper mesh and a multiwalled carbon nanotube modified by β -cyclodextrin, has good conductivity, can promote electron transfer, and further improves the rate of nutrient ions to be separated from colloid particle impurities and the determination efficiency of the nutrient ions in soil.
Detailed Description
The soil sampling test is carried out on the middle section of the south slope of Qinling mountains in Shaanxi province of China, and the method is used for measuring nutrient ions in soil, and the concrete test is as follows:
examples 1,
A method for determining nutrients in soil comprises the following steps,
a1, sampling: removing a 2-3cm surface layer on the soil surface, then sampling the soil from top to bottom, and sampling the soil to a depth of 0.7 m;
a2, liquid preparation: crushing, stirring and mixing the soil sampled in the step A1 uniformly, screening impurities by using a 60-mesh screen, taking 10g of the screened soil according to the mass fraction, adding 100g of deionized water, adding 2.5g of leaching agent, stirring for 15min under the high-speed stirring of 3000r/min at 2000-year rotation speed, stirring at the rotation speed of 50r/min, and hydrating for 1.5h to obtain a mixed solution;
a3, standing: placing the mixed solution obtained in the step A2 in an environment with the temperature of 35 ℃ and standing for 2.5 h;
a4, separation: under the stirring of a rotating speed of 50r/min, inserting two electrode plates into the mixed liquid, inputting steep pulse current to the two electrode plates, setting the peak value of the steep pulse at 160V, setting the pulse width at 0.6ms, setting the repetition frequency at 220kHz and setting the pulse gradient at 75 ns;
a5, centrifugation: after 12min of steep pulse separation, placing the separation liquid obtained in the step A4 in a centrifuge within 70 seconds, and centrifuging at the rotating speed of 10000-;
a6, measurement: after centrifugation, the supernatant was aspirated, and the nutrients in the supernatant were measured using an ultraviolet-visible spectrophotometer.
Wherein the leaching agent comprises NaHCO3Ethylenediaminetetraacetic acid and NaF.
Wherein, NaHCO3The mass of (3) is 2.5g and the concentration is 0.2moL/L, the mass of the ethylene diamine tetraacetic acid is 5g and the concentration is 0.012moL/L, and the mass of the NaF is 6g and the concentration is 0.012 moL/L.
Wherein the steep pulse current is an exponentially decaying pulse current.
The anode of the electrode plate is a carbon nano tube electrode, the cathode of the electrode plate is a copper mesh electrode, and the distance between the electrode plates is 4 cm.
The cathode is an electrode which is modified to a copper mesh by utilizing ordered mesoporous carbon-chitosan, and the anode is a multiwall carbon nanotube modified by β -cyclodextrin.
The manufacturing method of the electrode plate cathode comprises the following steps: comprises the following steps of (a) carrying out,
b1 polishing copper mesh by polishing copper mesh electrode with effective diameter of 11cm on chamois leather with particle size of 0.05-0.2 μm α -A1203Polishing the powder into a mirror surface;
b2, cleaning: cleaning the copper mesh electrode by using deionized water, and respectively carrying out ultrasonic oscillation cleaning for 15min in acetone, absolute ethyl alcohol and water to obtain a clean and bright copper mesh electrode;
b3, weighing ordered mesoporous carbon accounting for 15% of the total mass of the copper mesh electrode and a chitosan solution accounting for 85% of the total mass of the copper mesh electrode and having a concentration of 0.5%, dissolving the ordered mesoporous carbon in the chitosan solution, and performing ultrasonic dispersion for 25min to obtain a uniform ordered mesoporous carbon-chitosan dispersion liquid;
b4, absorbing the dispersion liquid obtained in the step B3 by using an injector, uniformly dripping the dispersion liquid on the surface of the copper mesh electrode, and drying the electrode for 10-15min under an infrared lamp to obtain the ordered mesoporous carbon-chitosan modified copper mesh electrode.
The manufacturing method of the electrode plate anode comprises the following steps: comprises the following steps of (a) carrying out,
c1 placing carbon nanotube electrode on chamois padα -A1 with a particle size of 0.05-0.2 μm is used203Polishing by powder;
c2, polishing the carbon nanotube electrode by using HNO3Ultrasonic cleaning with anhydrous ethanol and distilled water for 2-3min, and placing the cleaned carbon nanotube electrode in 0.5mol/L H2S03In the solution, circularly scanning at a potential interval of-0.3 to +1.0V at a scanning speed of 45mV/s until no peak exists, taking out the carbon nano tube electrode, washing the carbon nano tube electrode with distilled water, and storing the carbon nano tube electrode in the distilled water for later use;
c3, using the carbon nanotube electrode obtained in step C2 as a substrate electrode, at 4.5X 10-3β -cyclodextrin in mol/L and H in 0.5mol/L2S03In a medium, circularly scanning for 20 weeks at a sweeping speed of 90mV/s between the potential ranges of-0.6V to 1.2V under the static condition of the solution until a cyclic voltammetry curve is stable, then taking out an electrode, rinsing the surface of the electrode by deionized water, and drying;
c4, HNO in volume ratio3: HCl ═ 1: 3 refluxing for 12h to carboxylate the multi-wall carbon nano-tube, washing the multi-wall carbon nano-tube with 0.01mol/L NaOH until the pH value is 7, centrifuging and drying the multi-wall carbon nano-tube;
c5, weighing 5 parts of the multi-walled carbon nano-tube treated in the step C4, and ultrasonically dispersing in 7g of N, N-methylformamide for 30min to finally obtain stable dispersion liquid;
and C6, taking the dispersed liquid drops obtained in the step C5 by using an injector, modifying the surface of the electrode by β -cyclodextrin in the step C3, and drying under an infrared lamp to obtain the anode of the electrode plate.
Examples 2,
Compared with example 1, example 2 differs from example 1 only in that: example 2 no leaching agent was used in the extraction process.
Examples 3,
Compared with example 1, example 3 differs from example 1 only in that: example 3 extraction of nutrient ions from soil was carried out without using a steep pulse current to separate the nutrient ions from the soil.
Examples 4,
Compared with example 1, example 4 differs from example 1 only in that: example 4 in the case of separating nutrient ions from soil using a steep pulse current, the anode of the electrode plate was a carbon nanotube electrode and the cathode was a copper mesh electrode.
Through the tests of the 4 examples, the nutrient of 4 parts of soil taken out from the middle section of the south slope of Qinling mountains in Shaanxi province of China at the same time is determined, and the determination result is as follows:
through the above 4 examples, it can be seen that, the same soil produced in the same stage has different content of each nutrient ion measured by using the above 4 examples, while the ion content measured by using example 1 is the highest, and the ion content measured by using examples 2 to 4 is lower than that of example 1, which indicates that the leaching of nutrient ions in soil is insufficient in the tests of examples 2 to 4, and the nutrient ions in soil measured by using example 1 according to the method of the present invention are closer to the actual nutrient ion content in soil, so that the determination of nutrients in soil by using the method of example 1 is more accurate.
In addition, when the soil nutrient is measured by using the method in the embodiment 1, the time spent for one time is about 5 hours, and compared with the time for accurately measuring the soil nutrient in the prior art for 2-3 days, the measuring efficiency is higher.
Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims. The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.
Claims (8)
1. A method for determining nutrients in soil, characterized by: comprises the following steps of (a) carrying out,
a1, sampling: removing a 2-3cm surface layer on the soil surface, then sampling the soil from top to bottom, and sampling the soil to a depth of 0.5-1.5 m;
a2, liquid preparation: crushing the soil sampled in the step A1, stirring and mixing uniformly, screening impurities by using a 50-80-mesh screen, taking 10 parts of screened soil by mass, adding 80-100 parts of deionized water, adding 2-3 parts of leaching agent, stirring for 10-20min under the high-speed stirring of 2000-3000r/min, stirring at the rotating speed of 40-60r/min, and hydrating for 1-2h to obtain a mixed solution;
a3, standing: placing the mixed solution obtained in the step A2 in an environment with the temperature of 30-40 ℃ and standing for 2-3 h;
a4, separation: inserting two electrode plates into the mixed liquid under stirring at a rotating speed of 40-60r/min, inputting steep pulse current to the two electrode plates, setting the peak value of the steep pulse at 180V, the pulse width at 0.5-0.8ms, the repetition frequency at 300kHz and the pulse gradient at 50-100 ns;
a5, centrifugation: after 10-15min of steep pulse separation, placing the separation liquid obtained in the step A4 in a centrifuge within 60-80 seconds, and centrifuging at the rotating speed of 10000-;
a6, measurement: after centrifugation, the supernatant was aspirated, and the nutrients in the supernatant were measured using an ultraviolet-visible spectrophotometer.
2. A method for determining nutrients in soil according to claim 1, wherein: the leaching agent comprises NaHCO3Ethylenediaminetetraacetic acid and NaF.
3. A method for determining nutrients in soil according to claim 2, wherein: by mass parts, said NaHCO3The weight portion of the NaF is 2-3, the concentration is 0.1-0.3moL/L, the weight portion of the ethylene diamine tetraacetic acid is 4-6, the concentration is 0.01-0.015moL/L, the weight portion of the NaF is 5-7, and the concentration is 0.01-0.015 moL/L.
4. A method for determining nutrients in soil according to claim 3, wherein: the steep pulse current is an exponentially decaying pulse current.
5. The method of claim 4, wherein the nutrient is measured in the soil by: the anode of the electrode plate is a carbon nano tube electrode, the cathode of the electrode plate is a copper mesh electrode, and the distance between the electrode plates is 3-5 cm.
6. The method for determining nutrients in soil as claimed in claim 5, wherein the cathode is an electrode modified to copper mesh by ordered mesoporous carbon-chitosan, and the anode is multi-walled carbon nanotube modified by β -cyclodextrin.
7. The method of claim 6, wherein the nutrient is measured in the soil by: the manufacturing method of the electrode plate cathode comprises the following steps: comprises the following steps of (a) carrying out,
b1 polishing copper mesh by polishing copper mesh electrode with effective diameter of 10-12cm on chamois leather with particle size of 0.05-0.2 μm α -A1203Polishing the powder into a mirror surface;
b2, cleaning: cleaning the copper mesh electrode by using deionized water, and respectively carrying out ultrasonic oscillation cleaning for 15min in acetone, absolute ethyl alcohol and water to obtain a clean and bright copper mesh electrode;
b3, weighing ordered mesoporous carbon which accounts for 10-20% of the total mass of the copper mesh electrode, and a chitosan solution which accounts for 80-90% of the total mass of the copper mesh electrode and has a concentration of 0.5%, dissolving the ordered mesoporous carbon in the chitosan solution, and performing ultrasonic dispersion for 20-30min to obtain a uniform ordered mesoporous carbon-chitosan dispersion solution;
b4, absorbing the dispersion liquid obtained in the step B3 by using an injector, uniformly dripping the dispersion liquid on the surface of the copper mesh electrode, and drying the electrode for 10-15min under an infrared lamp to obtain the ordered mesoporous carbon-chitosan modified copper mesh electrode.
8. A method for determining nutrients in soil according to claim 7, wherein: the manufacturing method of the electrode plate anode comprises the following steps: comprises the following steps of (a) carrying out,
c1 placing carbon nanotube electrode on chamois padα -A1 with a particle size of 0.05-0.2 μm is used203Polishing by powder;
c2, polishing the carbon nanotube electrode by using HNO3Ultrasonic cleaning with anhydrous ethanol and distilled water for 2-3min, and placing the cleaned carbon nanotube electrode in 0.5mol/L H2S03In the solution, circularly scanning at a potential interval of-0.3 to +1.0V at a sweeping speed of 35-50mV/s until no peak exists, taking out the carbon nano tube electrode, washing with distilled water, and storing in the distilled water for later use;
c3, using the carbon nano tube electrode obtained in the step C2 as a substrate electrode, and the thickness of the carbon nano tube electrode is 4.0-5.0 multiplied by 10-3β -cyclodextrin in mol/L and H in 0.5mol/L2S03In a medium, circularly scanning for 20 weeks at a sweeping speed of 80-100mV/s between the potential ranges of-0.6V to 1.2V under the static condition of a solution until a cyclic voltammetry curve is stable, then taking out an electrode, rinsing the surface of the electrode by deionized water, and drying;
c4, HNO in volume ratio3: HCl ═ 1: refluxing for 12h for 3 to carboxylate the multi-wall carbon nano-tube, washing with 0.01mol/LNaOH until the pH is 6.5-7.5, centrifuging and drying;
c5, weighing 5 parts by weight of the multi-walled carbon nano-tube treated in the step C4 in 6-8 parts by weight of N, N-methylformamide, and ultrasonically dispersing for 30min to finally obtain stable dispersion liquid;
and C6, taking the dispersed liquid drops obtained in the step C5 by using an injector, modifying the surface of the electrode by β -cyclodextrin in the step C3, and drying under an infrared lamp to obtain the anode of the electrode plate.
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| CN101549218A (en) * | 2008-04-01 | 2009-10-07 | 哈尔滨理工大学 | Crude oil pre-dewatering and controlling equipment |
| JP2012027006A (en) * | 2010-06-25 | 2012-02-09 | Seiko Instruments Inc | Method for analyzing concentration of heavy metal ion or rare-earth metal ion |
| CN104344984A (en) * | 2014-11-27 | 2015-02-11 | 中国科学院地理科学与资源研究所 | Method for measuring available nutrients in soil |
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| CN101549218A (en) * | 2008-04-01 | 2009-10-07 | 哈尔滨理工大学 | Crude oil pre-dewatering and controlling equipment |
| JP2012027006A (en) * | 2010-06-25 | 2012-02-09 | Seiko Instruments Inc | Method for analyzing concentration of heavy metal ion or rare-earth metal ion |
| CN104344984A (en) * | 2014-11-27 | 2015-02-11 | 中国科学院地理科学与资源研究所 | Method for measuring available nutrients in soil |
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