CN1296140C

CN1296140C - Physical sorting method of atmosphere micro dust particles

Info

Publication number: CN1296140C
Application number: CNB03113582XA
Authority: CN
Inventors: 杨冠玲; 何振江; 李丰果; 彭力; 邱健
Original assignee: South China Normal University
Current assignee: South China Normal University
Priority date: 2003-01-16
Filing date: 2003-01-16
Publication date: 2007-01-24
Anticipated expiration: 2023-01-16
Also published as: CN1589973A

Abstract

The present invention relates to a physical separating method for atmosphere micro dust particles. The present invention comprises the steps of connection among a cutting head, a double distilled water particle receiving device, a flow controller and an air extractor, sampling, sampling drying, microscopic observation, particle separation, particle separation, etc. The method can realize the separation of particles below PM2.5 in the atmosphere and has the advantages of easy operation and favourable separating effect.

Description

The physical separation method of atmospheric fallout particle

(1) technical field

The present invention relates to a kind of from atmospheric aerosol the method for sorting variable grain size, particularly diameter is less than the method for separating of the particle of 2.5 μ m, it can separate the particle of different shape in the atmospheric aerosol effectively, can be used for more effectively the formation of atmospheric aerosol and the analysis of chemistry, and the further optical effect of analyse atmos aerosol particle.

(2) background technology

At present in the world how the acquisition method of atmospheric aerosol is gathered particle in the atmosphere with the particle hits device, and these particles are captured on the film, or particle is captured in the diameter that electron microscope uses is on the copper mesh of 3mm.Copper mesh will as applying the supporting film of collodion earlier, plate carbon film again through some processing, and particle directly is captured on the carbon film, carries out projection with rhotanium, observes with transmission electron microscope again.Can determine its composition by this method for particle with specific form structure.But this method formality is cumbersome, and filters with copper mesh and also may lose many information, adds with the viewed grain amount of this method fewly, promptly uses trace analysis also often to be difficult to carry out with chemical analysis, has not more talked sorting.

(3) Fa Ming content

The objective of the invention is at the deficiencies in the prior art, realize the sorting of PM2.5 in the atmosphere following (be diameter less than 2.5 microns particle, down with) particle with the method for physics, method is easy and simple to handle, good separation effect.

Concretely, the inventive method comprises the steps:

(1) gathers airborne particulate with the multistage or single-stage ram that generally adopts both at home and abroad (or claiming cutting head), with the obstructed filter membrane of particle gathered but directly feed in the redistilled water, collect particle by redistilled water;

(2) take out 0.1～0.3 milliliter of sample liquid that contains particle in the intact back of sample collection, place on flat board 1 plate with bright and clean plane, and make it dry;

(3) 1 plate that will have a dry residue places under the microscopical object lens, microscopical visual field is positioned on the dry residue, divide 1～3 time it to be applied flowability liquid a little (each 1～3) preferably, with separating granular, till observing clean micronic dust particle and presenting;

(4) same 2 plates that require of horizontal positioned below 1 plate, the liquid that 1 plate has inclined with 2 plates become α angle (scope at α angle can at 1～85 degree range changing) better to be easy to volatilize with the flowability of 0.2～2 ml vol washes away 1 plate (particle on 1 plate separates), when the lower limb of mobile arrival 1 plate that washes away liquid, make between 1 plate and 2 plates and slide along parallel direction is relative, on 2 plates, can be sorted into size this moment with the equally distributed relatively particle that the delivery time successively changes, on 1 plate, stay clean mobile relatively poor particle.

In step of the present invention (1), the sampling time of gathering airborne particulate with cutting head can be a several hrs according to the cleannes decision of local air, also can twenty or thirty hour or more than.The concrete operations that redistilled water is collected particle are: the gas outlet at cutting head connects a flexible pipe, the other end and a hollow tube at flexible pipe join, hollow tube passes rubber stopper and is inserted in the bottle with two necks that redistilled water is housed, another of bottle mouthful links to each other with the bleeding point of sampling controller, the bleed power supply of controller of connection, the atmosphere of being gathered can enter in the redistilled water by cutting head and hollow tube.

In step of the present invention (2), the extraction of sample liquid generally adopts pipette or buret to carry out, and the dry run of sample liquid is relevant with environment temperature and humidity, generally needs tens minutes to three, four hours, in order to reduce the interference of environment, require this step to carry out at clean environment.

In step (3), flowability liquid preferably can adopt redistilled water, ethanol etc., and the number of times of its dropping decides according to the selection and the different of particle of aforesaid liquid with the amount of dropping, presents with the micronic dust particle that can better observe cleaning to be as the criterion.

In the step (4); the size of the angle α of 1 plate and 2 plates is as the criterion so that granule or circular granular thing can flow out and non-rounded grain or the bigger particle generation of flow resistance are flowed with fluid according to the level and smooth degree on 1 plate surface, the size of particle, the selection and the consumption decision of flush liquid.The concrete operations that liquid washes away are: use impregnator or buret on reference axis Z direction, evenly apply liquid along the reference axis directions X.The concrete operations of parallel relative slip are as follows between 1 plate and 2 plates: drag 1 plate along reference axis+Y direction, or drag 2 plates along reference axis-Y direction, also can drag 2 plates along reference axis-Y direction when reference axis+Y direction drags 1 plate.The rate request that slides is moderate, to reach result that particle can carry out sorting for well.

In the present invention, the whole operation process is carried out in clean environment, might add other small quantities of particles in the process of dry run or dropping liquid, but can ignore.

The principle of the inventive method foundation is as follows:

The particle of Brownian movement is under the surface tension effects of liquid evaporation in the liquid, when surface tension during greater than the frictional force between Brownian movement power and particle and the holder, the motion of particle is influenced by the cohesive force of surface tension and particle mainly can assemble the residue after formation is done admittedly to the direction of liquid contraction.When utilizing a separation principle to apply a strength greater than the depolymerize power of cohesive force, adhesive force and the particle of particle and the stiction summation between the holder, just can will accumulate in around the bigger material or the smaller particles on surface is separated to doing residue after solid.Utilize hydrokinetic process of washing away, the characteristics that granule has a better flowability than bulky grain reach the sorting of variable grain.

The present invention compared with prior art has following advantage or effect:

(1) only utilize cutting head can't carry out the separation and the sorting of particle by the filter membrane sampling airborne particulate at present, the present invention can realize the separation and the sorting of Atmospheric particulates well.

(2) prior art because observed grain amount is few, promptly uses trace analysis also often to be difficult to carry out with chemical analysis with the particle on the transmission electron microscope observing copper mesh.Utilize the present invention can obtain the allied substances of more amount, form very valuable further understanding atmospheric aerosol.

(3) the present invention adopts physical method sorting airborne particulate, can not produce the characteristic of particle to change.

(4) description of drawings

Fig. 1 is the flow chart of the inventive method

Fig. 2 is an operation chart of collecting particle in the inventive method with redistilled water

Fig. 3 is the schematic diagram of relative slip between 1 plate and 2 plates in the inventive method

Fig. 4 is the various particles after the inventive method sorting.

(5) concrete embodiment

As seen from Figure 1, the inventive method comprises being connected between cutting head and distilled water particle picker, flow controller, the air exhauster; Sampling; Sampling is dry; Microexamination; Particle separation; Steps such as grain sorting.

As seen from Figure 2, the concrete operations that redistilled water is collected particle are: after sampling controller started, the sampling atmosphere entered redistilled water particle picker by glass-tube, and gas is drawn out of by outlet after picker and is discharged into atmosphere again.

In Fig. 3,1 expression, 1 plate, 2 expressions, 2 plates.Relative slip can be to drag 1 plate along reference axis+Y direction between 1 plate and 2 plates, or drags 2 plates along reference axis-Y direction, also can drag 2 plates along reference axis-Y direction when reference axis+Y direction drags 1 plate.

As seen from Figure 4, this method has realized the physical separation of air micronic dust particle preferably.This figure is with the PM2.5 cutting head of Anderson240 type and the sampling apparatus of redistilled water particle collector composition, on the height of building, Guangzhou Environmental Protection Science Research Institute layer 6, acquisition time is 33 hours air samples of being gathered.Get 0.2 milliliter in its liquid sample, after the air dry, under the low power objective of ME600L differential interference phase-contrast microscope, observe, and drip successively with 3 and analyze straight alcohols, make particle separation after, spend in 60 degree scopes from 15, change the angle of 1 plate and 2 plates, evenly wash away with 1.2 milliliters of ethanol simultaneously, and under the situation of 25 millimeters of the positions of 1 plate that slides, the result who under same microscope high power objective, observes after the sorting.The distribution of residue on 1 plate in 3 presentation graphs 3, the distribution of particle after the sorting on 4 expressions, 2 plates.

Claims

1, a kind of physical separation method of atmospheric fallout particle is characterized in that comprising the steps:

(1) gathers airborne particulate with cutting head, with the obstructed filter membrane of particle gathered but directly feed in the redistilled water, collect particle by redistilled water;

(2) take out 0.1～0.3 milliliter of sample liquid that contains particle in the intact back of sample collection, place on flat board 1 plate (1) with bright and clean plane, and make it dry;

(3) will have 1 plate (1) of doing solid residue and place microscopically, microscopical visual field is positioned on the dried solid residue, divide 1～3 time, each 1～3 it is applied flowability liquid preferably, with separating granular, till observing clean micronic dust particle and presenting;

(4) same 2 plates (2) that require of horizontal positioned below 1 plate (1), 1 plate (1) has inclined and has become the α angle with 2 plates (2), liquid mobile better, that be easy to volatilize with 0.2～2 ml vol washes away 1 plate (1), when the lower limb of mobile arrival 1 plate (1) that washes away liquid, make between 1 plate (1) and 2 plates (2) and slide along parallel direction is relative, on 2 plates (2), can be sorted into size this moment with the equally distributed particle that the delivery time successively changes, on 1 plate (1), stay clean mobile relatively poor particle.

2, the method for claim 1, it is characterized in that: in the step (1), the concrete operations of collecting particle with redistilled water are: the gas outlet at cutting head connects a flexible pipe, the other end of flexible pipe and a hollow tube join, hollow tube passes rubber stopper and is inserted in the bottle with two necks that redistilled water is housed, another of bottle mouthful links to each other with the bleeding point of sampling controller, connects the power supply of the controller of bleeding, and the atmosphere of being gathered enters in the redistilled water by cutting head and hollow tube.

3, the method for claim 1 is characterized in that: in the step (2), the extraction of sample liquid adopts pipette or buret to carry out, and the dry run of sample liquid is carried out at clean environment.

4, the method for claim 1 is characterized in that: in step (3), flowability liquid preferably adopts redistilled water or ethanol.

5, as claim 1 or 2 or 3 or 4 described methods, it is characterized in that: in the step (4), 1 plate (1) is 1 °～85 ° with the scope of the angle α of 2 plates (2); The concrete operations that liquid washes away are: use impregnator or buret on reference axis Z direction, evenly apply liquid along the reference axis directions X; The concrete operations of relative slip are as follows between 1 plate (1) and 2 plates (2): drag 1 plate (1) along reference axis+Y direction, or drag 2 plates (2) along reference axis-Y direction, also can when dragging 1 plate (1), reference axis+Y direction drag 2 plates (2) along reference axis-Y direction.