CN115308320B - Method for quantifying hydrophobic organic pollutants in soil and forming residual combined state through action of hydrophobic organic pollutants and humic acid - Google Patents
Method for quantifying hydrophobic organic pollutants in soil and forming residual combined state through action of hydrophobic organic pollutants and humic acid Download PDFInfo
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- QJZYHAIUNVAGQP-UHFFFAOYSA-N 3-nitrobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid Chemical compound C1C2C=CC1C(C(=O)O)C2(C(O)=O)[N+]([O-])=O QJZYHAIUNVAGQP-UHFFFAOYSA-N 0.000 title claims abstract description 139
- 239000004021 humic acid Substances 0.000 title claims abstract description 139
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- 230000002209 hydrophobic effect Effects 0.000 title claims abstract description 43
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- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical group CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 claims description 98
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 24
- 239000007853 buffer solution Substances 0.000 claims description 24
- 239000000356 contaminant Substances 0.000 claims description 24
- 239000000243 solution Substances 0.000 claims description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 230000001186 cumulative effect Effects 0.000 claims description 17
- 238000003756 stirring Methods 0.000 claims description 11
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- 238000002474 experimental method Methods 0.000 claims description 10
- 238000004128 high performance liquid chromatography Methods 0.000 claims description 9
- 238000006073 displacement reaction Methods 0.000 claims description 8
- 239000012528 membrane Substances 0.000 claims description 8
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 6
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N dimethyl sulfoxide Natural products CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 5
- 230000001502 supplementing effect Effects 0.000 claims description 5
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- IAZDPXIOMUYVGZ-WFGJKAKNSA-N Dimethyl sulfoxide Chemical group [2H]C([2H])([2H])S(=O)C([2H])([2H])[2H] IAZDPXIOMUYVGZ-WFGJKAKNSA-N 0.000 claims 1
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- MXWJVTOOROXGIU-UHFFFAOYSA-N atrazine Chemical compound CCNC1=NC(Cl)=NC(NC(C)C)=N1 MXWJVTOOROXGIU-UHFFFAOYSA-N 0.000 description 3
- 239000011324 bead Substances 0.000 description 3
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- KBPLFHHGFOOTCA-UHFFFAOYSA-N 1-Octanol Chemical compound CCCCCCCCO KBPLFHHGFOOTCA-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
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- -1 water is 4:1:95 Chemical compound 0.000 description 1
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Abstract
The invention discloses a method for quantifying hydrophobic organic pollutants in soil, which is characterized in that the hydrophobic organic pollutants are added into humic acid organic solution, humic acid aggregate is prepared by a dialysis method, the pollutants are wrapped in the aggregate, then a release test is carried out, then the release condition of the organic pollutants wrapped on the humic acid aggregate under different pH values is researched by release dynamics, the residual bonding state on the humic acid aggregate can be further analyzed from microcosmic, and then the formation process of the humic acid aggregate, the wrapping of the humic acid aggregate on the hydrophobic organic pollutants and the release process of the wrapped organic pollutants are inspected by dissipative particle dynamics simulation.
Description
Technical Field
The invention belongs to the technical field of environmental chemistry and organic pollutant chemotaxis, and particularly relates to a method for quantifying hydrophobic organic pollutants in soil, wherein the hydrophobic organic pollutants react with humic acid to form a residual combined state.
Background
Hydrophobic organic pollutants (HOCs) are a class of organic pollutants that have a large octanol/water partition coefficient, low water solubility, are generally difficult to degrade, are prone to accumulate in soil and sediment, and are transported over long distances through environmental media. With the rapid development of economy and the acceleration of people's pace of life, a large number of HOCs are released into the environment. HOCs have the characteristics of durability, difficult degradation, high biotoxicity and the like in the environment, and have great influence on human health and ecological environment.
Humic acid in soil and sediment plays an important role in the environment, and has great influence on the distribution, migration and bioavailability of hydrophobic organic pollutants in the soil environment. Therefore, the residual bonding state formed by interaction between the hydrophobic organic pollutant and the humic acid is explored, and the method has obvious environmental significance.
In view of the fact that in the prior art, through a mode of combining experiments and simulation, the research on quantifying the residual combined state of organic pollutants under the mediation of humic acid in soil is little, and the action mechanism is difficult to explain from a microscopic angle, but the defect of an experimental means can be supplemented to a certain extent by a simulation method, so that development of a method for quantifying the hydrophobic organic pollutants in the soil, which is reacted with the humic acid to form the residual combined state, is urgently needed.
Disclosure of Invention
The invention provides a method for quantifying hydrophobic organic pollutants in soil, which can be used for quantifying the residual combined state of organic pollutants under the mediation of humic acid in soil through combination experiments and calculation simulation, and has remarkable environmental significance for accurately evaluating the environmental behaviors and effects of the organic pollutants.
In order to achieve the above object, the technical scheme of the present invention is as follows.
A method for quantifying hydrophobic organic contaminants in soil that react with humic acid to form a residual bound comprising the steps of:
(1) Formation of humic acid aggregate coated organic pollutant and coating amount measurement:
respectively dissolving humic acid and hydrophobic organic pollutants in the same organic solvent, mixing the hydrophobic organic pollutant solution and the humic acid solution, stirring, dialyzing in deionized water by using a dialysis bag, periodically changing water, and freeze-drying after the dialysis is finished to obtain humic acid aggregates, wherein the organic pollutants are wrapped in the aggregates;
weighing 1mg humic acid aggregate coated with organic pollutant, dissolving in 10mL methanol, ultrasonic treating for 20min to dissolve the coated pollutant in methanol, passing through 0.45 μm filter membrane, measuring pollutant concentration by high performance liquid chromatography, and measuringDetermining the mass of the organic pollutants coated on the humic acid aggregate, and calculating the quantity E of the organic pollutants coated on the humic acid aggregate through a formula Wrapping contaminants ：
Combining the experimental results to obtainCan be given m Humic acid And m is equal to Wrapping contaminants Is m Wrapping contaminants ＝0.47m Humic acid ；
(2) Release experiment of organic pollutants coated on humic acid aggregate:
placing PBS buffer solution of humic acid aggregate into a dialysis bag, placing the PBS buffer solution into a beaker filled with the same PBS buffer solution, keeping the temperature constant at room temperature, stirring, extracting the buffer solution in the cup every time (1-24 h), and immediately supplementing an equal amount of fresh buffer solution for keeping the total volume of the solution unchanged, and measuring the accumulated release amount Er of organic pollutants on the humic acid aggregate by using high performance liquid chromatography:
wherein: er is the cumulative release of organic contaminants,%; ve is the buffer displacement volume, mL; v (V) 0 Is the total volume of the buffer solution, mL; c (C) i Sample concentration, mg/L, at the time of sampling for the ith displacement; m is m Wrapping contaminants The mass of the organic pollutants coated on the humic acid aggregate is mg; n is the number of times the buffer is replaced;
the amount of the hydrophobic organic pollutant wrapped by the humic acid aggregate in the soil can be released along with the change of the pH condition of the soil, and the relation between the release amount and the pH value is Y= -0.0501X+0.7215, R 2 =0.9964, y is the cumulative release of organic contaminants,%; x is the pH value of the soil, so that the soil can be calculatedAfter the environmental pH is changed, a part of the pollutant is still not released and is wrapped in the humic acid aggregate, namely the mass m of the pollutant residual combination state Residue (C) The mass of the residual bound of contaminants can be calculated by the following formula:
m residue (C) ＝0.47m Humic acid ×(1+0.0501X-0.7215)
＝0.47m Humic acid ×(0.2785+0.0501X)
Wherein m is Humic acid The mass of humic acid in the soil is shown, and X is the pH value of the soil.
Further, the mass ratio of the humic acid to the hydrophobic organic pollutant in the step (1) is 1:1, and the hydrophobic organic pollutant is dibutyl phthalate.
Further, the organic solvent in the step (1) is preferably dimethyl sulfoxide or dimethylformamide.
Further, the stirring time in the step (1) is preferably 4 to 6 hours, more preferably 4 hours.
Further, the molecular weight cut-off of the dialysis bag of step (1) is preferably 8000Da.
Further, the dialysis time in the step (1) is preferably 24 hours, water is exchanged every 1 hour in the first 4 hours in the dialysis process, water is exchanged every 4 hours in the period of 4-12 hours, and water is exchanged every 6 hours after 12 hours.
Further, the molecular weight cut-off of the dialysis bag of step (2) is preferably 8000Da.
Further, the concentration of the humic acid aggregate in the PBS buffer solution of the humic acid aggregate in the step (2) is 0.5-1.5 mg/mL, preferably 1mg/mL.
Further, the temperature in the step (2) is preferably 20 to 30 ℃, more preferably 25 ℃; the stirring rate is preferably 70 to 150r/min, more preferably 100r/min.
Further, the volume of the buffer solution in each extracting cup in the step (2) is preferably 3-6 mL, more preferably 4mL.
Further, the method for obtaining the release amount versus pH value curve Y= -0.0501X+0.7215 in the step (2) specifically comprises the following steps:
(1) Accurately weighing 5mg of humic acid aggregate, dissolving in 5mL of prepared PBS buffer solution with pH value of 4.0-9.0, dividing the solution into three parts under each pH value condition, respectively transferring into three dialysis bags with molecular weight cut-off of 8000Da, placing the dialysis bags in a beaker, adding 115mL of PBS buffer solution corresponding to the dialysis bags as a release medium into the beaker, placing the beaker on a magnetic stirrer, setting stirring speed of 100r/min, carrying out release experiment at 25 ℃, taking out 3-6 mL of solution from the beaker at intervals of 1-24 h during release, supplementing fresh buffer solution corresponding to the same volume, filtering the obtained samples with a filter membrane with 0.45 mu m, measuring the concentration of the organic pollutants released from the humic acid aggregate by high performance liquid chromatography, and calculating the accumulated release amount Er of the organic pollutants:
wherein: er is cumulative release of organic contaminants,%; ve is the buffer displacement volume, mL; v (V) 0 Is the total volume of the buffer solution, mL; c (C) i Sample concentration, mg/L, at the time of sampling for the ith displacement; m is m Wrapping contaminants The mass of the organic pollutants on the humic acid aggregate is mg; n is the number of times the buffer is replaced;
(2) Fitting the corresponding organic pollutant cumulative release amounts under different pH conditions, and making a functional relation diagram of the corresponding organic pollutant cumulative release amounts under different pH conditions to obtain a relation of the organic pollutant cumulative release amounts and the pH value as Y= -0.0501X+0.7215, wherein Y is the organic pollutant cumulative release amount; x is the pH value.
The invention also examines the formation process of humic acid aggregate and the wrapping of the humic acid aggregate on hydrophobic organic pollutants through the dissipative particle dynamics simulation, the release process of the wrapped organic pollutants, and the residual bonding state of the organic pollutants under the mediation of humic acid in the soil is quantified from a microscopic angle, and then the method is combined with experiments, so that the residual bonding state of the organic pollutants under the mediation of humic acid in the soil can be quantified.
The bioavailability of the residual bonding state is low, and the formation of the residual bonding state is considered as a process for reducing the toxicity of pollutants, so that the amount of the residual bonding state formed by the hydrophobic organic pollutants under the mediation of the soil humic acid aggregate is calculated, and a certain theoretical guidance is provided for judging the environmental behaviors and effects of the organic pollutants in the soil.
The invention mainly explores the process of wrapping the humic acid aggregate on the hydrophobic organic matters and the release condition of the organic pollutants wrapped on the humic acid aggregate under different pH conditions, and can intuitively embody the morphological change process of the humic acid aggregate and the release process of the organic pollutants from the aggregate by means of dissipative particle dynamics simulation, thereby being more beneficial to quantifying the residual bonding state of the organic pollutants under the mediation of humic acid in soil from a microscopic angle.
The invention quantifies the residual bonding state formed under the interaction mediation of hydrophobic organic pollutants and humic acid through experiments, firstly, the hydrophobic organic pollutants are added into a humic acid organic solution, then humic acid aggregate is prepared through a dialysis method, and the pollutants are wrapped in the aggregate; the release kinetics is used for researching the release condition of organic pollutants wrapped on humic acid aggregates under different pH conditions, so that the residual bonding state (the part which can not be released in the release process) on the humic acid aggregates can be quantitatively analyzed from a macroscopic scale; the invention also examines the formation process of humic acid aggregate and the wrapping of the humic acid aggregate on the hydrophobic organic pollutant through the dissipative particle dynamics simulation, the release process of the wrapped organic pollutant reflects the residual bonding state of the organic pollutant under the mediation of humic acid from the microscopic angle, and the invention intuitively reflects the process of the morphological change of the humic acid aggregate and the wrapping of the humic acid aggregate on the hydrophobic organic pollutant through the simulation, and the release process of the wrapped organic pollutant is combined with the experiment, so that the residual bonding state of the organic pollutant under the mediation of humic acid in soil can be quantified, and the invention has obvious environmental significance for accurately evaluating the environmental behavior and effect of the organic pollutant.
Drawings
FIG. 1 is a graph showing the cumulative release of DBP under different pH conditions for humic acid aggregates;
FIG. 2 is a graph fitted with a function of the cumulative release of organic contaminants for different pH conditions;
FIG. 3 is a structural model of humic acid, DBP and water molecules and coarse-grained model thereof;
FIG. 4 is a schematic illustration of the process of humic acid aggregate formation;
FIG. 5 is a schematic representation of humic acid agglomerates versus DBP encapsulation;
FIG. 6 is a graph of radial distribution function analysis of equilibrium phase diagram of humic acid agglomerates versus DBP encapsulation;
FIG. 7 is a graph showing the dynamic profile of the release of DBP from humic acid aggregates and the graph of radius of gyration analysis.
Detailed Description
In order to better understand the present invention, the following describes the technical scheme of the present invention in detail with reference to specific embodiments.
The humic acid selected in the invention is extracted from soil, and dibutyl phthalate (DBP) is purchased from Ala-dine.
Example 1
Preparation of humic acid aggregate coated DBP and coating amount measurement:
accurately weighing 20mg of humic acid and 20mg of DBP, respectively dissolving in 40mL of dimethyl sulfoxide, adding the DBP solution into the humic acid solution, stirring for 4 hours, then placing into a dialysis bag with the molecular weight cut-off of 8000Da for dialysis for 24 hours, changing water every 1 hour before the dialysis process, changing water every 4 hours, changing water every 6 hours after the dialysis process, and freeze-drying after the dialysis is finished to obtain humic acid agglomerates coated with DBP, wherein the organic pollutants DBP are coated in the agglomerates;
1mg of the humic acid aggregate coated with DBP is weighed and dissolved in 10mL of methanol, the ultrasonic treatment is carried out for 20min, the coated DBP is completely dissolved in the methanol, then the solution passes through a filter membrane with the thickness of 0.45 mu m, the concentration of the DBP is measured by high performance liquid chromatography, the mass of the coated DBP on the humic acid aggregate is measured, and then the quantity of the coated DBP of the humic acid aggregate is calculated by a formula (1):
combining the experimental results to obtainCan be given m Wrapping DBP And m is equal to Humic acid Is m Package dbp= 0.47m Humic acid 。
Example 2
Release experiment of coated DBP on humic acid agglomerates at different pH values:
accurately weighing 5mg of humic acid aggregate, respectively dissolving in 5mL of prepared PBS buffer solution with pH value of 4.0, 7.0 and 9.0, dividing the solution into three parts under each pH condition, respectively transferring into three dialysis bags with molecular weight cut-off of 8000Da, placing the dialysis bags in a beaker, adding 115mL of PBS buffer solution corresponding to the dialysis bags into the beaker as a release medium, placing the beaker on a magnetic stirrer, setting stirring speed to be 100r/min, carrying out release experiment of organic pollutants at 25 ℃, taking out the solution from the beaker at intervals of 1h, 2h, 4h, 6h, 8h, 12h, 24h, 36h, 60h, 84h, 108h, 132h and 156h during release, taking out 4mL of solution from the beaker each time, immediately supplementing 4mL of buffer solution corresponding to the dialysis bags, passing the obtained sample through 0.45 mu m of buffer solution, measuring the concentration of humic acid aggregate from the acid aggregate in 156h by using a high performance liquid chromatography, and calculating the accumulated release amount of DBP (DBP 2) of the filter membrane in the filter membrane after the determination of the DBP (DBP 2):
wherein: er: cumulative DBP release,%; ve: buffer displacement volume, mL; v (V) 0 : total volume of buffer, mL; c (C) i : sample concentration, mg/L, at the ith displacement sampling; m is m DBP : the mass of DBP on humic acid aggregate, mg; n: the number of buffer substitutions;
the cumulative DBP release amounts in the release medium at pH values 4.0, 7.0 and 9.0 are shown in fig. 1, and at ph=4.0, the cumulative DBP release amounts are highest, reaching about 60%; at ph=7.0, the cumulative release of DBP is about 40%; at ph=9.0, the cumulative release of DBP is about 25%, the corresponding cumulative release of organic pollutants in 156h under different pH conditions is plotted on the left, see fig. 2, and the relationship between the cumulative release and the pH is obtained by fitting:
Y＝-0.0501X+0.7215 (3)
wherein Y is the accumulated release amount of the organic pollutants,%; x is pH value, R 2 ＝0.9964；
The residual bonding state mass m of the corresponding organic pollutant DBP on the humic acid aggregate under different pH conditions can be obtained Residue (C) The calculation formula is as follows:
m residue (C) ＝0.47m Humic acid ×(1-Y)
＝0.47m Humic acid ×(1+0.0501X-0.7215)
＝0.47m Humic acid ×(0.2785+0.0501X) (4)
Wherein m is Humic acid The mass of humic acid in the soil is shown, and X is the pH value of the soil.
The DBP wrapped on the soil humic acid aggregate can be released to a certain extent along with the change of the pH condition of the soil, but a part of pollutants can not be released, a pollutant residual bonding state is formed, and the accumulated release amount of the DBP is gradually reduced along with the increase of the pH value, so that the DBP is unstable under the protonation condition, the DBP is easy to release from the aggregate, and the humic acid aggregate is stable under the deprotonation condition, so that a spherical structure of a core-shell is formed, and the DBP can be better wrapped in a core area, so that the DBP is difficult to release.
The formation process of humic acid aggregate, the wrapping of the humic acid aggregate on hydrophobic organic pollutants and the release process of the wrapped organic pollutants are simulated by adopting dissipative particle dynamics, and the specific steps are as follows:
(1) Using Materials Studio software to construct model of humic acid, DBP (black beads) and water molecule in simulation system, coarsening and corresponding beads as shown in figure 3, adopting all-in-oneThe sub-dynamics calculates Flory-Huggins parameters of each bead, and further calculates interaction force parameters among the beads according to a dissipative particle dynamics theory, and a simulation system is constructed to be as large asThe system with the size can effectively avoid the influence caused by the periodic boundary effect;
(2) Construction using Build Mesostructure part of Materials Studio softwareAccording to the number ratio of humic acid: the water is 5:95 to fill a simulation system, selecting Geometry Optization tasks by a mesoite module to perform structural optimization on the constructed simulation system, and then simulating the formation process of humic acid aggregates by using DPD tasks, wherein at first, humic acid and water in the system are distributed in a solution in a random dispersed state, and as the number of simulation steps increases, different segments of humic acid start to agglomerate under the action of hydrophilicity/hydrophobicity; with the continuous increase of the step number, small aggregates formed by humic acid gradually tend to form a sphere due to the surface tension effect, and the small aggregates are mutually close and collide to be fused into large aggregates;
(3) Construction using Build Mesostructure part of Materials Studio softwareAccording to the quantity ratio of humic acid to DBP, namely, water is 4:1:95, filling the simulation system, selecting Geometry Optization tasks by using a mesoite module to perform structural optimization on the constructed simulation system, then simulating the process of humic acid aggregates on hydrophobic organic pollutants under the condition of protonation and deprotonation by using DPD tasks, wherein the humic acid and the DBP are distributed in a solution in a random dispersed state at first, and small aggregates formed by the humic acid are mutually gathered and collide with each other along with the continuous increase of the steps, so that the large aggregates are fused; the hydrophobic organic pollutant DBP gradually begins to agglomerate under the hydrophobic effect and gradually diffuses to humic acidThe core layer area of the agglomerate is shown in fig. 6 (a), after that, the number of steps is increased continuously, the shape and the size of the humic acid agglomerate are kept unchanged, which indicates that the simulation system reaches equilibrium, the humic acid agglomerate wrapping DBP is formed, the initial state and the intermediate state of the system are basically similar when the deprotonation condition is compared with the protonation condition, the pollutant agglomerate is also in the core layer area of the humic acid agglomerate, as shown in fig. 6 (B), except that the agglomerate formed by humic acid is relatively small, the pH value response fragment is converted from the protonation to the deprotonation, the hydrophilicity of the agglomerate fragment is caused, and the structure of the humic acid agglomerate is changed;
(4) The Mesocite module is utilized, the simulation step length is 100000 steps, the release process of the humic acid aggregate wrapping DBP under the deprotonation condition is simulated, the DBP is wrapped in the core layer area of the humic acid aggregate, the conversion from protonation to deprotonation occurs to the pH value response segment from hydrophobicity to hydrophilicity is carried out along with the increase of the simulation step number, the segment stretches to a hydrophilic area, the aggregate with a spherical structure swells from inside to outside to rupture, the aggregate presents the most loose state, and a certain amount of DBP is exposed and diffused from the hydrophobic area; as the number of steps is increased, the swelling degree is reduced until the swelling degree disappears; the core layer segment (P) and the middle layer segment (D) of the agglomerate shrink towards the core, respectively, the pH responsive segment (a) also shrinks slightly, and the DBP is recoated in the core region of the agglomerate to form a three-layer, relatively compact, spherical structure of "core-middle layer-shell", at which time DBP is difficult to release from the agglomerate (corresponding to a low experimental pH), indicating that at high pH conditions the amount of contaminants encapsulated by the humic acid agglomerate is relatively high, and as the pH decreases, the amount of contaminants encapsulated by the humic acid agglomerate gradually decreases, describing a dynamic process of humic acid-mediated formation of residual bound state of contaminants in a semi-quantitative manner.
Example 3
The method provided in example 1 was verified, 200mg of farmland soil in a certain area was randomly taken, poured into a beaker, the pH=7.4 of the soil was measured, 100mL of deionized water was added according to the conventional method, the pH value of the solution was adjusted to 10, the solution was stirred for 1h and then allowed to stand for 12h, the supernatant was collected, the supernatant was centrifuged, the lower precipitate (humic acid and possibly contained organic pollutants) was collected, the precipitate was dissolved in 50mL of methanol, the contaminants were completely dissolved in methanol by ultrasonic treatment for 20min, 4mL of the solution was taken and passed through a 0.45um filter membrane, the concentration of atrazine in the solution was measured with a high performance liquid chromatography ultraviolet detector at a wavelength of 220nm, the mass of atrazine residual bound in humic acid was 0.89mg, the mass of atrazine residual bound in humic acid was about 0.84mg when the pH value was calculated to 10 by the equation (4) in example 1, and the experimental deviation was not significant in the two equation (4) because of the pH value was adjusted and the other substances were disturbed in the experimental results.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above examples, and any other changes, modifications, substitutions, and simplifications that do not depart from the spirit and principles of the present invention are intended to be included in the scope of the present invention.
Claims (6)
1. A method for quantifying hydrophobic organic contaminants in soil that interact with humic acid to form a residual bound state, comprising the steps of:
(1) Respectively dissolving humic acid and hydrophobic organic pollutants in the same organic solvent, mixing the hydrophobic organic pollutant solution and the humic acid solution, stirring, dialyzing in deionized water by using a dialysis bag, periodically changing water, and freeze-drying after the dialysis is finished to obtain humic acid aggregates coated with the organic pollutants; 1mg of humic acid aggregate coated with organic pollutants is weighed and dissolved in 10mL of methanol, ultrasonic treatment is carried out, the coated organic pollutants are completely dissolved in the methanol, the mixture passes through a filter membrane with the thickness of 0.45 mu m, the pollutant concentration is measured by high performance liquid chromatography, the mass of the organic pollutants coated on the humic acid aggregate is measured, and the quantity E of the organic pollutants coated on the humic acid aggregate is calculated Wrapping contaminants ：
Combining the experimental results to obtain E Wrapping contaminants ＝0.32，m Package contamination = 0.47m Humic acid ；
(2) Placing PBS buffer solution of humic acid aggregate into dialysis bag, placing in the same PBS buffer solution, stirring at constant temperature, extracting buffer solution every 1-24 h, supplementing fresh buffer solution with equal amount, and measuring accumulated release amount Er of organic pollutant on humic acid aggregate by high performance liquid chromatography:
wherein: er is the cumulative release of organic contaminants,%; ve is the buffer displacement volume, mL; v (V) 0 Is the total volume of the buffer solution, mL; c (C) i Sample concentration, mg/L, at the time of sampling for the ith displacement; m is m Wrapping contaminants The mass of the organic pollutants coated on the humic acid aggregate is mg; n is the number of times the buffer is replaced;
the amount of the humic acid aggregate coated with the hydrophobic organic pollutant in the soil can be released along with the change of the pH value of the soil, and the relation between the release amount and the pH value is shown as follows:
Y＝-0.0501X+0.7215 (3)
wherein Y is the accumulated release amount of the organic pollutants,%; x is the pH value of the soil;
calculating the mass m of the residual combination state of pollutants in humic acid aggregates in soil with different pH values Residue (C) ：
m Residue (C) ＝0.47m Humic acid ×(0.2785+0.0501X) (4)
Wherein m is Humic acid The mass of humic acid in the soil is shown, and X is the pH value of the soil.
2. The method for quantifying hydrophobic organic contaminants in soil that react with humic acid to form residual bound according to claim 1, wherein the mass ratio of humic acid to hydrophobic organic contaminants in step (1) is 1:1; the hydrophobic organic pollutant is dibutyl phthalate and the organic solvent is dimethyl sulfoxide or dimethylformamide.
3. The method for quantifying hydrophobic organic pollutants in a residual combined state formed by the action of humic acid in soil according to claim 1, wherein the stirring time in the step (1) is 4-6 h; the dialysis time is 24h, water is changed every 1h in the first 4h in the dialysis process, water is changed every 4h, and water is changed every 6h after 12 h.
4. The method for quantifying hydrophobic organic contaminants in soil that interact with humic acid to form residual bound according to claim 1 wherein the molecular weight cut-off of the dialysis bags of step (1) and step (2) is 8000Da.
5. The method for quantifying hydrophobic organic contaminants in soil that react with humic acid to form residual bound according to claim 1, wherein the concentration of humic acid aggregate in PBS buffer of the humic acid aggregate in the step (2) is 0.5-1.5 mg/mL.
6. The method for quantifying hydrophobic organic pollutants in a residual combined state formed by the action of humic acid in soil according to claim 1, wherein the relation curve Y= -0.0501X+0.7215 of the release amount and the pH value in the step (2) is obtained by the following steps:
(1) Weighing 5mg of humic acid aggregate, dissolving in 5mL of prepared PBS buffer solution with pH value of 4.0-9.0, dividing each pH value solution into three equal parts, respectively transferring into three dialysis bags with molecular weight cut-off of 8000Da, placing the dialysis bags into a beaker, adding 115mL of PBS buffer solution which is the same as that in the dialysis bags into the beaker as a release medium, carrying out a release experiment at a stirring speed of 100r/min and a temperature of 25 ℃, taking out 3-6 mL of solution from the beaker at intervals of 1-24 h during release, supplementing the fresh buffer solution with the same volume corresponding to the solution, filtering the obtained samples with a filter membrane with the volume of 0.45 mu m, measuring the concentration of organic pollutants released from the humic acid aggregate by using high performance liquid chromatography, and calculating the accumulated release Er of the pollutants, wherein the calculation formula is shown as formula (2);
(2) Fitting the corresponding organic pollutant accumulated release amounts under different pH conditions to obtain the relationship between the organic pollutant accumulated release amounts and the pH value as Y= -0.0501X+0.7215, wherein Y is the organic pollutant accumulated release amount,%; x is the pH value of the soil.
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| CN105203374A (en) * | 2015-09-16 | 2015-12-30 | 中国环境科学研究院 | Method for extracting small-molecule humic acid from soil through XAD resin |
| CN105548389A (en) * | 2015-12-14 | 2016-05-04 | 南京大学 | Method for analyzing contents of three different occurrence forms of organic pollutants in soil |
| WO2018008986A1 (en) * | 2016-07-06 | 2018-01-11 | 주식회사 삼양바이오팜 | In vitro release testing method and evaluation method of polymer micelle preparation containing poorly water-soluble drug |
| DE102017222295A1 (en) * | 2017-12-08 | 2019-06-13 | Axagarius Gmbh & Co. Kg | Kits and methods for removing contaminants from a sample containing nucleic acid |
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| CN105203374A (en) * | 2015-09-16 | 2015-12-30 | 中国环境科学研究院 | Method for extracting small-molecule humic acid from soil through XAD resin |
| CN105548389A (en) * | 2015-12-14 | 2016-05-04 | 南京大学 | Method for analyzing contents of three different occurrence forms of organic pollutants in soil |
| WO2018008986A1 (en) * | 2016-07-06 | 2018-01-11 | 주식회사 삼양바이오팜 | In vitro release testing method and evaluation method of polymer micelle preparation containing poorly water-soluble drug |
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