CN113262727A - Method for extracting soil nano colloid - Google Patents
Method for extracting soil nano colloid Download PDFInfo
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- CN113262727A CN113262727A CN202110430788.XA CN202110430788A CN113262727A CN 113262727 A CN113262727 A CN 113262727A CN 202110430788 A CN202110430788 A CN 202110430788A CN 113262727 A CN113262727 A CN 113262727A
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- 239000002689 soil Substances 0.000 title claims abstract description 85
- 239000000084 colloidal system Substances 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000000725 suspension Substances 0.000 claims abstract description 23
- 229910021642 ultra pure water Inorganic materials 0.000 claims abstract description 20
- 239000012498 ultrapure water Substances 0.000 claims abstract description 20
- 238000003756 stirring Methods 0.000 claims abstract description 12
- 238000000108 ultra-filtration Methods 0.000 claims abstract description 11
- 239000000126 substance Substances 0.000 claims abstract description 9
- 238000001132 ultrasonic dispersion Methods 0.000 claims abstract description 7
- 238000000227 grinding Methods 0.000 claims abstract description 6
- 239000007788 liquid Substances 0.000 claims abstract description 6
- 238000007873 sieving Methods 0.000 claims abstract description 6
- 238000007605 air drying Methods 0.000 claims abstract description 5
- 150000002500 ions Chemical class 0.000 claims abstract description 5
- 238000002156 mixing Methods 0.000 claims abstract description 5
- 239000002245 particle Substances 0.000 claims description 20
- 238000000502 dialysis Methods 0.000 claims description 10
- 238000005119 centrifugation Methods 0.000 claims description 8
- 238000000605 extraction Methods 0.000 claims description 6
- 239000004695 Polyether sulfone Substances 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 239000012528 membrane Substances 0.000 claims description 4
- 229920006393 polyether sulfone Polymers 0.000 claims description 4
- 239000011347 resin Substances 0.000 claims description 4
- 229920005989 resin Polymers 0.000 claims description 4
- 239000012615 aggregate Substances 0.000 claims description 3
- 239000002681 soil colloid Substances 0.000 claims description 2
- 239000011521 glass Substances 0.000 abstract description 4
- 239000000203 mixture Substances 0.000 abstract description 3
- 239000007787 solid Substances 0.000 abstract 1
- 239000006228 supernatant Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000002572 peristaltic effect Effects 0.000 description 3
- 238000004062 sedimentation Methods 0.000 description 3
- 238000003917 TEM image Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000008236 biological pathway Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000001246 colloidal dispersion Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 230000037361 pathway Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses a method for extracting soil nano colloid, which mainly comprises the steps of air-drying soil to be extracted, grinding and sieving the soil, and uniformly mixing the sieved soil. And adding ultrapure water into the uniformly mixed soil and stirring the mixture by using a glass rod to obtain a soil suspension. Then carrying out ultrasonic dispersion treatment on the soil suspension, and transferring the upper layer liquid into a centrifugal tube; and (4) centrifuging the components transferred into the centrifugal tube to obtain the soil nano colloidal suspension. Finally, concentrating the soil nano colloid suspension by using a tangential flow ultrafiltration method; dialyzing the concentrated solution by using ultrapure water to remove redundant ions and small molecular substances in the concentrated solution; and (4) centrifugally concentrating to obtain soil nano colloid solid.
Description
Technical Field
The invention relates to the field of soil chemistry, in particular to a method for extracting soil nano colloid.
Background
The nano colloid is a highly dispersed nano-scale multiphase inhomogeneous system in the environment, and consists of two substances in different states, namely a dispersed phase and a continuous phase, and is also called nano colloidal dispersion or a mixture. Generally, the natural environment is classified into two categories, one is naturally formed in nature, and the other is artificially synthesized and then released into an environmental system. The soil nano colloid is colloid particles with the particle size of 1-100nm formed in the process of forming natural soil, has various components and is one of the main sources of the natural nano colloid. Biological pathways (microorganisms act on animal and plant residues), non-biological pathways (mineral weathering) and combined pathways of the two are three main modes for forming soil nano colloids, and the specific forming process is quite complex. Research shows that the soil nano colloid can absorb nutrients and participate in earth element circulation, and compared with large-particle soil colloid particles, the nano colloid has the characteristics of large specific surface area and small size, and is easy to interact with pollutants in the environment so as to influence the migration and transformation processes of the soil nano colloid in the environment, such as heavy metals of cadmium, chromium, lead and the like. In conclusion, soil nano-colloids have characteristics different from those of macro-particles, so that it is necessary to extract the soil nano-colloids to study their unique physicochemical properties and environmental effects.
At present, a unified standard method for separating and extracting soil nano colloid does not exist, common methods comprise a vibration-sedimentation method, a chemical dispersion-sedimentation method, a centrifugal sedimentation method and the like, some original characteristics of the soil nano colloid can be damaged by adopting chemical dispersion, and the physical dispersion has the defects of long extraction time, small extraction amount and incapability of batch extraction; in addition, the operation conditions of the currently adopted extraction method are not strict enough, and human errors are easily introduced into the extracted products, particularly the granularity; the extracted nano colloid has large particle size range variation, lacks of uniform standard and cannot ensure the parallelism and the accuracy of analysis.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for effectively extracting nano colloids from soil.
The technical scheme of the invention is a method for extracting soil nano colloid, which comprises the following steps:
(1) and (3) air-drying the soil to be extracted, grinding and sieving, and uniformly mixing the sieved soil.
(2) And adding ultrapure water into the uniformly mixed soil and stirring the mixture by using a glass rod to obtain a soil suspension.
(3) And carrying out ultrasonic dispersion treatment on the soil suspension, and taking the upper layer liquid to transfer into a centrifugal tube.
(4) And (4) centrifuging the components transferred into the centrifugal tube to obtain the soil nano colloidal suspension.
(5) Concentrating the soil nano colloid suspension by using a tangential flow ultrafiltration method.
(6) And dialyzing the concentrated solution by using ultrapure water to remove redundant ions and small molecular substances in the concentrated solution.
(7) And (4) placing the dialyzed soil nano colloid suspension into a centrifugal concentrator for centrifugal concentration to obtain soil nano colloid.
Furthermore, the soil nano colloid is in the form of aggregates, and the size of each single particle is less than 100 nm.
Further, the particle size distribution of the soil nano colloid is mainly between 10.33nm and 90.13 nm.
Further, the average particle size of the soil nano colloid is 29.95 nm.
Further, in the step (2), the mass ratio of the soil to the ultrapure water is 1: 100-1: 20.
Further, in the step (3), a washing tank type ultrasonic instrument is adopted for ultrasonic dispersion, and the working frequency is set to be 40 KHz.
Further, the parameters of the centrifugation in the step (4): the temperature is 4 ℃, the rotating speed is 6030rpm/min, the time is 20min, and the centrifugation is carried out for three times.
Further, the soil nano colloid solution obtained by concentrating the step (5) by adopting a tangential flow ultrafiltration technology.
Wherein, the rotating speed of the peristaltic pump in the tangential flow ultrafiltration technology is 100-140 rpm/min.
Wherein, the molecular weight cut-off of the membrane is 5kDa, and the material is polyether sulfone resin.
Further, the step (5) is finally concentrated into 30-40ml of concentrated solution.
Further, the molecular weight cut-off of the dialysis bag in the step (6) is 5kDa, the dialysis bag is placed in a 1L beaker containing ultrapure water, and the ultrapure water is changed every 4 hours with stirring for 12 hours on a magnetic stirrer at the stirring speed of 150 rpm/min.
Further, the temperature of the centrifugal concentration centrifugal chamber in the step (7) is set to-20 ℃, the centrifugal rotating speed is set to 2000rpm/min, and the centrifugal concentration is carried out for 36 hours.
The method for extracting the soil nano colloid can be used for extracting nano particles with low loss in large batch under the condition of not adding any chemical substance, and the technical progress is mainly reflected in that:
1. the soil liquid after ultrasonic dispersion does not need long-time standing operation, and the extraction time is greatly shortened.
2. The obtained soil nano colloid suspension is concentrated by using a tangential flow ultrafiltration method, so that the sample loss caused by split charging is reduced, and the quality of the obtained soil nano colloid is improved.
3. And finally, the original freeze drying method is replaced by a centrifugal concentration method, so that the required time is greatly shortened.
4. In addition, the range of the particle size of the nano colloid extracted by the method of the invention presents a uniform trend, and the parallelism and the accuracy of analysis are ensured.
Drawings
FIG. 1 is a flow diagram of the method of the present invention;
FIGS. 2 and 4 are TEM images of the extracted soil nanocolloid;
fig. 3 and 5 are particle size distribution diagrams of the extracted soil nanocolloid based on TEM observation statistics.
Detailed Description
The invention is further described below with reference to the following figures and specific examples.
Example 1
The embodiment of the invention selects yellow soil which is collected from a certain paddy field in Anhui Anqing.
(1) Naturally air-drying the collected soil, removing gravel, plant residual roots and the like, grinding and sieving by a 10-mesh sieve, and uniformly mixing the sieved soil.
(2) And adding 1L of ultrapure water into 50g of the uniformly mixed soil, and stirring for 5-10 min by using a glass rod to obtain a soil suspension.
(3) The soil suspension was ultrasonically dispersed for 1h, and the supernatant liquid was transferred to a 50ml centrifuge tube.
(4) And (3) centrifuging the components transferred into the centrifugal tube, wherein the centrifugation speed is set to 6030rpm/min, the centrifugation temperature is 4 ℃, centrifuging for 20min, and centrifuging for three times, and taking supernatant each time to obtain the soil nano colloidal suspension.
(5) Concentrating 600mL of soil nano colloid suspension by using a tangential flow ultrafiltration method, and finally concentrating to 30mL, wherein the molecular weight cutoff of a membrane is 5kDa, the material is polyether sulfone resin, and the rotating speed of a peristaltic pump is set to be 120 rpm/min.
(6) And dialyzing the concentrated solution by using ultrapure water to remove redundant ions and small molecular substances in the concentrated solution, wherein the molecular weight cut-off of a dialysis bag is 5kDa, placing the dialysis bag in a 1L beaker containing the ultrapure water, stirring for 12h on a magnetic stirrer at the stirring speed of 150rpm/min, and replacing the ultrapure water every 4 h.
(7) And (4) performing centrifugal concentration to obtain soil nano colloid, wherein the temperature of a centrifugal chamber is set to be-20 ℃, the centrifugal rotating speed is set to be 2000rpm/min, and the centrifugal concentration time is 24 h.
Example 2
The embodiment of the invention selects brown soil which is collected from a certain paddy field in the New countryside of Henan.
(1) Naturally air-drying the collected soil, removing gravel, plant residual roots and the like, grinding and sieving by a 10-mesh sieve, and uniformly mixing the sieved soil.
(2) And adding 1L of ultrapure water into 50g of the uniformly mixed soil, and stirring for 5-10 min by using a glass rod to obtain a soil suspension.
(3) The soil suspension was ultrasonically dispersed for 1h, and the supernatant liquid was transferred to a 50ml centrifuge tube.
(4) And (3) centrifuging the components transferred into the centrifugal tube, wherein the centrifugation speed is set to 6030rpm/min, the centrifugation temperature is 4 ℃, centrifuging for 20min, and centrifuging for three times, and taking supernatant each time to obtain the soil nano colloidal suspension.
(5) Concentrating 600mL of soil nano colloid suspension by using a tangential flow ultrafiltration method, and finally concentrating to 40mL, wherein the molecular weight cutoff of a membrane is 5kDa, the material is polyether sulfone resin, and the rotating speed of a peristaltic pump is set to be 100 rpm/min.
(6) And dialyzing the concentrated solution by using ultrapure water to remove redundant ions and small molecular substances in the concentrated solution, wherein the molecular weight cut-off of a dialysis bag is 5kDa, placing the dialysis bag in a 1L beaker containing the ultrapure water, stirring for 12h on a magnetic stirrer at the stirring speed of 150rpm/min, and replacing the ultrapure water every 4 h.
(7) And (4) performing centrifugal concentration to obtain soil nano colloid, wherein the temperature of a centrifugal chamber is set to be-20 ℃, the centrifugal rotating speed is set to be 2000rpm/min, and the centrifugal concentration time is 24 h.
As is clear from the TEM images shown in fig. 2 and 4, the extracted soil nanocolloids were in the form of aggregates, and the size thereof was over the nanometer scale, but the individual particle size was 100nm or less. Fig. 3 and 5 show the particle size distribution diagrams of the extracted yellow soil nano colloid and brown soil nano colloid respectively, specifically, the particle size of the nano colloid extracted from the yellow soil is mainly between 10.33nm and 90.13nm, the average particle size is 29.95nm, the particle size of the nano colloid extracted from the brown soil is mainly between 1.87nm and 95.68nm, and the average particle size is 42.22nm, which confirms that the extracted soil nano colloid belongs to the nano scale.
Claims (10)
1. The method for extracting the soil nano colloid is characterized by comprising the following steps of:
(1) grinding and sieving: air-drying the soil to be extracted, grinding and sieving, and uniformly mixing the sieved soil;
(2) preparing a soil suspension: adding ultrapure water into the uniformly mixed soil obtained in the step (1) and stirring to obtain a soil suspension;
(3) ultrasonic dispersion: carrying out ultrasonic dispersion treatment on the soil suspension, and transferring the upper-layer liquid into a centrifugal tube;
(4) centrifugal extraction: centrifuging the components transferred into the centrifugal tube to obtain a soil nano colloidal suspension;
(5) tangential flow ultrafiltration concentration: concentrating the soil nano colloid suspension by using a tangential flow ultrafiltration method;
(6) and (3) dialysis: dialyzing the concentrated solution by using ultrapure water to remove redundant ions and small molecular substances in the concentrated solution;
(7) centrifuging and concentrating the soil colloid concentrated solution obtained after dialysis to obtain soil nano colloid;
the soil nano colloid is in the form of aggregates, and the sizes of single particles are all below 100 nm.
2. The method of claim 1, wherein the soil nanocolloid has a particle size distribution that is predominantly between 10.33nm and 90.13 nm.
3. The method of claim 1, wherein the soil nano-colloid has an average particle size of 29.95 nm.
4. The method according to claim 1, wherein the mass ratio of the soil to the ultrapure water in the step (2) is 1:100 to 1: 20.
5. The method according to claim 1, wherein the ultrasonic dispersion treatment of step (3) is carried out by using a launder-type ultrasonic instrument.
6. The method of claim 1, wherein the parameters of the centrifugation of step (4): the temperature is 4 ℃, the rotating speed is 6030rpm/min, the time is 20min, and the centrifugation is carried out for three times.
7. The method of claim 1, wherein the pump speed in the tangential flow ultrafiltration in step (5) is 100-140 rpm/min.
8. The method of claim 7, wherein the tangential flow ultrafiltration membrane has a molecular weight cut-off of 5kDa and is a polyethersulfone resin material;
finally concentrating to obtain 30-40ml concentrated solution.
9. The method for extracting soil nano-colloids as claimed in claim 1, wherein the molecular weight cut-off of the dialysis bag in step (6) is 5kDa, the dialysis bag is placed in a 1L beaker containing ultrapure water, and the ultrapure water is changed every 4 hours with stirring for 12 hours on a magnetic stirrer at the speed of 150 rpm/min.
10. The method for extracting soil nano-colloids according to claim 1, wherein the step (7) adopts a centrifugal concentrator, the temperature of a centrifugal chamber is set to-20 ℃, the centrifugal rotating speed is set to 2000rpm/min, and the centrifugal concentrating time is 24 h.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113670882A (en) * | 2021-09-01 | 2021-11-19 | 南开大学 | Method for analyzing interaction between soil nano colloid and cadmium by utilizing two-dimensional correlation spectrum |
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| CN101580587A (en) * | 2009-03-30 | 2009-11-18 | 山东阜丰生物科技开发有限公司 | Novel technology for extracting polyglutamic acid |
| CN101607691A (en) * | 2009-07-14 | 2009-12-23 | 浙江大学 | A kind of method of extracting nano particle in the soil |
| US20100272770A1 (en) * | 2008-01-04 | 2010-10-28 | Wim De Windt | Silver nanoparticles with specific surface area and a method for producing them |
| WO2018203347A1 (en) * | 2017-05-01 | 2018-11-08 | Council Of Scientific & Industrial Research | A process for interfacial separation of metal nanoparticles or nanowires using centrifugal separators |
| CN109370316A (en) * | 2018-10-16 | 2019-02-22 | 嘉兴学院 | Two-step method prepares the method and conductive ink of highly concentrated nano Argent grain conductive ink |
| CN111707624A (en) * | 2020-06-15 | 2020-09-25 | 南开大学 | Qualitative and quantitative analysis method for environmental nano-colloids in river water |
-
2021
- 2021-04-21 CN CN202110430788.XA patent/CN113262727A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100272770A1 (en) * | 2008-01-04 | 2010-10-28 | Wim De Windt | Silver nanoparticles with specific surface area and a method for producing them |
| CN101580587A (en) * | 2009-03-30 | 2009-11-18 | 山东阜丰生物科技开发有限公司 | Novel technology for extracting polyglutamic acid |
| CN101607691A (en) * | 2009-07-14 | 2009-12-23 | 浙江大学 | A kind of method of extracting nano particle in the soil |
| WO2018203347A1 (en) * | 2017-05-01 | 2018-11-08 | Council Of Scientific & Industrial Research | A process for interfacial separation of metal nanoparticles or nanowires using centrifugal separators |
| CN109370316A (en) * | 2018-10-16 | 2019-02-22 | 嘉兴学院 | Two-step method prepares the method and conductive ink of highly concentrated nano Argent grain conductive ink |
| CN111707624A (en) * | 2020-06-15 | 2020-09-25 | 南开大学 | Qualitative and quantitative analysis method for environmental nano-colloids in river water |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113670882A (en) * | 2021-09-01 | 2021-11-19 | 南开大学 | Method for analyzing interaction between soil nano colloid and cadmium by utilizing two-dimensional correlation spectrum |
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