Based on water quality heavy metal online analyzer and the analytical approach of XRF technology
Technical field
The invention belongs to environmental monitoring technology field, be specifically related to a kind of water quality heavy metal online analyzer based on XRF technology and analytical approach.
Background technology
Along with the quickening of China's process of industrialization, the heavy metal pollution in water pollution problems particularly wide basin has become the main Environmental Problems of restriction socio-economic development, urgently solves from source.And crop heavy metal excessive problem derivative is thus also for mankind's health care belt has carried out great impact.Therefore, the exploitation for water quality heavy metal online analyzer and analytical approach has great importance.
The water quality heavy metal online analyzer of main flow in the market, mainly adopts photometry or Anodic stripping.Photometry technology relative maturity, good stability.But method sensitivity is not high, Element detection selectivity is not strong, is subject to coexisting ion interference, developer has response to a lot of metallic ion sometimes, cannot detect for various heavy, and chemical reagent may produce secondary pollution simultaneously, the detection of the complicated water sample of low concentration cannot be met.Anodic stripping is based on electrochemical method, detects complicated mechanism, and method is responsive, and repeatability wants specific luminosity method poor.Sensitivity and selectivity good, detectability can reach μ g/L, can realize the detection of the various heavy such as lead, cadmium, copper simultaneously.But instrument maintenance requires higher, especially electrode polishing is safeguarded, maintainer needs could grasp through professional training and long practice.
In addition, the producer realizing heavy metal analysis technology in water quality based on XRF technology mainly contains XOS company of the U.S. at present, uses X ray Single wavelength spectral technique, can carry out on-line monitoring at present for Pb and As, detect and be limited to 30 μ g/L.But this appliance requires uses expensive analyzing crystal to realize the light splitting of X incident ray and fluorescence signal, and is limited to analyzing crystal, not all element can detection.Meanwhile, instrument cost is higher, light path relative complex, and environmental suitability is slightly poor.
Summary of the invention
The object of the present invention is to provide a kind of water quality heavy metal online analyzer based on XRF technology and analytical approach, adopt water sample atomization in conjunction with XRF Dynamic Non-Destruction Measurement, can carry out on-line analysis for water quality heavy metal, sensitivity, stability, reappearance are outstanding.
For achieving the above object, technical scheme of the present invention is as follows:
Water quality heavy metal online analyzer of the present invention comprises: water sample atomization system, example enrichment system, detection system, strainer kinematic train and control acquisition system.The atomized sample that water sample atomization system produces, example enrichment system is transferred to by silicone tube (or metal tube), after completing example enrichment, enrichment spot is sent to detection system by strainer kinematic train, and the above-mentioned control of each system and the collection of data are completed by built-in intelligent software automatic synchronization by controlling acquisition system.Water sample atomization system, example enrichment system, strainer kinematic train and detection system are connected with control acquisition system by data line.
Water sample atomization system of the present invention comprises: sampling peristaltic pump 1, sample cell 2, first liquid level gauge 3, second liquid level gauge 4, ultrasonic atomizer 5, first solenoid valve 6, second solenoid valve 7, air compressor 8, venturi scrubber 9, exsiccator 10; Sampling peristaltic pump 1, first solenoid valve 6, sample cell 2 are connected by flexible pipe.Ultrasonic atomizer 5 is fixed on sample cell 2 bottom by fixed screw.First liquid level gauge 3 and the second liquid level gauge 4 are individually fixed in sample cell upper and lower, can be determined the atomization volume of sample liquid by difference in height.All connected by silicone tube (or metal tube) between sample cell 2, second solenoid valve 7, venturi scrubber 9, exsiccator 10, the position that silicone tube (or metal tube) enters sample cell 2 will, lower than the second liquid level gauge 4, guarantee to extract water sample atomization.Air compressor 8 provides pure air for the atomization of water sample by flexible pipe to venturi scrubber 9.Collection, quantitatively atomization that this system mainly realizes water sample form aerosol particle, by the heavy metal salt in water being formed after drying dry particle.
Example enrichment system of the present invention comprises: the 3rd solenoid valve 11, sampling pipe lifting motor 12, sample stage 13, particulate filter 14, flow-control module 15, sampling pump 16.Be between exsiccator 10, the 3rd solenoid valve 11 metal tube connect, sampling pipe lower end under the action of sampling pipe lifting motor 12, sampling pipe by extruding strainer 28 can and sample stage 13 between form airtight sample space.Connected by flexible pipe between sample stage 13, particulate filter 14, flow-control module 15, sampling pump 16.Enrichment system is drawn into strainer surface by the particle of the drying produced by atomization system and carries out enrichment, realizes the enrichment of heavy metal substance in water.
Described detection system comprises: X ray light pipe 17, light pipe high-voltage power supply 18 and XRF detecting device 19.X ray light pipe 17 is connected by high-tension bus-bar with light pipe high-voltage power supply 18.Light pipe high-voltage power supply 18 and XRF detecting device 19, be connected with industrial PC 31 by data line, controlled by intelligent software.Detection system is positioned at the right side of sample stage 13, the top of strainer 28, by XRF technology, realizes the detection to different heavy metal.
Described strainer kinematic train comprises: feed belt wheel 20, take-up pulley 21, smoothly take turns 22-25, pinch roller 26, transmission shaft 27, strainer 28.Feed belt wheel 20, first smooth take turns 22 and the 3rd smoothly take turns 24, pinch roller 26, transmission take out 27 and be positioned on the left of sample stage 13, feed belt wheel 20 and constantly can release strainer, then rotated by the coordination of each several part strainer 28 is conveyed into example enrichment system.4th smooth take turns 25 and second smoothly take turns 23, take-up pulley 21 is positioned on the right side of sample stage 13.Take-up pulley 21 is by rotating the strainer can constantly packed up through detecting.Strainer 28 two ends are wound in feeds on belt wheel 20 and take-up pulley 21, and the collaborative motion of the two, can realize the continuous folding and unfolding of strainer 28.The transmission of strainer sample between enrichment system and detection system is realized by the friction force between pinch roller 26 and transmission shaft 27.Feed belt wheel 20, take-up pulley 21 and carry out corresponding folding and unfolding strainer along with the transmission of strainer, the smooth 22-25 that takes turns ensures smooth at whole transmission process of strainer 28.
Control acquisition system of the present invention comprises: water sample atomization control circuit board 29, enrichment transmission control circuit plate 30, industrial PC 31 and intelligent software.Water sample atomization control circuit board 29, enrichment driving circuit plate 30 is connected with industrial PC 31 by data line, and intelligent software is installed in industrial PC 31.
The use power of X ray light pipe 17 is 10-100W; XRF detecting device 19 is SDD type.
The detectability for most of heavy metal element of this analyser can reach 1 μ g/L.
A kind ofly the described water quality heavy metal on-line analysis based on XRF technology is adopted to comprise the following steps:
1) water sampling, atomization and example enrichment: first the first solenoid valve 6, second solenoid valve 7 is all in open mode, water sample is squeezed in sample cell 2 by sampling pipe by sampling peristaltic pump 1, until after the liquid level in sample cell 2 detected by the first liquid level gauge 3, close sampling peristaltic pump 1 and stop sampling, close the first solenoid valve 6 again, guarantee the consistance of each sampling quantity.Then start ultrasonic atomizer 5 and start beginning primary atomization, air compressor 8 startup subsequently drives venturi scrubber 9 to be atomized further.Air-flow after atomization is by exsiccator 10, and removed by the water produced in aerosol particle, form dry particle, heavy metal substance can reside in Particle Phase.When venturi scrubber 9 is opened, synchronous unlatching the 3rd solenoid valve 11, sampling pipe lifting motor 12 declines, and is clamped by strainer 28 between sample stage 13, forms confined space.Open sampling pump 16, synchronously carry out the example enrichment of dried particles thing.Flow controller 15 controls the gas circuit speed of evacuation, ensures the stability of sampling.Particulate filter 14, for the protection of flow controller, prevents blocking.Along with the carrying out of atomization, when the liquid level in sample cell 2 drops to the second liquid level gauge 4 place, ultrasonic atomizer 5, air compressor 8, second solenoid valve 7 first cuts out.(be generally set as 20s) after time delay certain hour, the 3rd solenoid valve 11, sampling pump 16 is closed successively.Sampling pipe lifting motor 12 rises.Complete the collection of sample, atomization and enrichment process.
2) water sample is discharged: after water sample atomization and enrichment complete, the first solenoid valve 6 and the second solenoid valve 7 are opened, and all liq in sample cell 2 is discharged by sampling peristaltic pump 1, completes this sampling, and evacuated tube road, prepare the collection of next water sample.
3) sample detection: the strainer completing enrichment, is run to by gearing and detects position, and industrial PC 31 controls to open light pipe high-voltage power supply 18, X ray light pipe 17 and XRF detecting device 19 automatically.Industrial PC 31 software completes the acquisition and processing of spectrogram, according to built-in working curve, finally can be calculated the concentration of corresponding heavy metal in water sample in conjunction with the data gathered.
In above-mentioned steps, X ray light pipe 17, XRF detecting device 19 are all configured by the software systems in industrial PC 31 detection time.Adopt Non-Destructive Testing, be kept at the sample on strainer, can retain and detect further for laboratory.
Beneficial effect of the present invention is:
1, the present invention is based on XRF technology water quality heavy metal online analyzer, the characteristic spectrum of different heavy metal element need not, therefore the method can realize the same detection of water quality detection device for multi metallic elements.Without the need to any chemical reagent, decrease maintenance cost, it also avoid the secondary pollution problem of chemical reagent simultaneously;
2, present invention employs water sample atomization and enrichment method, there is the Monitoring lower-cut of μ g/L magnitude, and by regulating enrichment ratio, the detection (μ g/L-g/L) of wide dynamic detection range can be realized, surface water and Online monitoring of pollution sources needs can be met simultaneously;
3, the XRF detection technique that the present invention adopts is lossless detection method, can reclaim test sample compared with existing main stream approach, is convenient to realize the recovery of same sample, retention and laboratory and rechecks;
4, sampling of the present invention and detecting portion physical isolation, is more applicable to operating mode on-the-spot, can reduces the cost of maintenance greatly;
Accompanying drawing explanation
Fig. 1 is the water quality heavy metal online analyzer system schematic that the present invention is based on XRF technology.Wherein, sampling peristaltic pump 1, sample cell 2, first liquid level gauge 3, second liquid level gauge 4, ultrasonic atomizer 5, first solenoid valve 6, second solenoid valve 7, air compressor 8, venturi scrubber 9, exsiccator 10, draw together the 3rd solenoid valve 11, sampling pipe lifting motor 12, sample stage 13, particulate filter 14, flow-control module 15, sampling pump 16, X ray light pipe 17, light pipe high-voltage power supply 18, XRF detecting device 19, feed belt wheel 20, take-up pulley 21, first smoothly takes turns 22, second smoothly takes turns 23, 3rd smoothly takes turns 24, 4th smoothly takes turns 25, pinch roller 26, transmission shaft 27, strainer 28, water sample atomization control circuit board 29, enrichment transmission control circuit plate 30, industrial PC 31.
Fig. 2 is the spectrogram of content of heavy metal lead in certain lead waste water of measuring of the water quality heavy metal online analyzer based on XRF technology of the present invention.
Embodiment
Water quality heavy metal online analyzer of the present invention comprises: water sample atomization system, example enrichment system, detection system, strainer kinematic train and control acquisition system.The atomized sample that water sample atomization system produces, example enrichment system is transferred to by silicone tube (or metal tube), after completing example enrichment, enrichment spot is sent to detection system by strainer kinematic train, and the above-mentioned control of each system and the collection of data are completed by built-in intelligent software automatic synchronization by controlling acquisition system.Water sample atomization system, example enrichment system, strainer kinematic train and detection system are connected with control acquisition system by data line.
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.
The present invention is the water quality heavy metal online analyzer based on XRF technology, and system comprises water sample atomization system, example enrichment system, detection system, strainer kinematic train and controls acquisition system.
Collection, quantitatively atomization that water sample atomization system mainly realizes water sample form aerosol particle, then form the dried particles thing of heavy metal salt after further drying.
As shown in Figure 1, sampling peristaltic pump 1, sample cell 2, the first liquid level gauge 3, second liquid level gauge 4, ultrasonic atomizer 5, the first solenoid valve 6, second solenoid valve 7, air compressor 8, venturi scrubber 9, exsiccator 10.All connected by flexible pipe between above-mentioned each parts, the flexible pipe lower end in sample cell 2 needs to be placed in below the second liquid level gauge 4, ensures all to be in below liquid level in whole atomization process, can extract water sample and be atomized.
The heavy metal salt particle that example enrichment system is used for water sample atomization system produces is enriched in strainer surface, improves the concentration of measurand, improves Monitoring lower-cut and the stability of holistic approach instrument.
As shown in Figure 1, example enrichment system mainly comprises the 3rd solenoid valve 11, sampling pipe lifting motor 12, sample stage 13, particulate filter 14, flow-control module 15, sampling pump 16.For flexible pipe connects between exsiccator 10, the 3rd solenoid valve 11, sampling pipe lifting motor 12.Sampling pipe lifting motor 12 lower end is metal tube, after ensureing to decline can and sample stage 13 between formed and seal.Sample stage 13, particulate filter 14, flow-control module 15 and sampling pump 16 are all connected by flexible pipe.
Water quality heavy metal principle of enrichment in strainer is as follows: utilize water sample atomization system, by the sequential control designed, ensures that the water sample amount of each atomization is consistent.By air suction sampling, by the heavy metal particles thing enrichment after atomization drying and strainer surface.In enrichment process, industrial PC 31 can record the volume V of water quality atomization
l, the concentration of certain water quality heavy metal wherein detected is C
l.Subsequently, the concentration obtained by detection system is C
s, on strainer, the area of particle concentrations is S
s.Wherein C
s, C
l, S
s, V
lmeet formula below:
C
s×S
s=C
l×V
l
Due to S
s, V
lknown, obtain C by detection system
s, just obtain C by above-mentioned formulae discovery
l, namely obtain the concentration of corresponding heavy metal in actual water sample.
Detection system is based on the XRF technology of line, comprise and use the X ray light pipe 17 and SDD type detecting device 19 that power is 10-100W, SDD type detecting device 19 adopts electricity refrigeration, integrated level is high, technology maturation, there is higher detection efficiency and energy resolution, effective detection of most of Characteristics of Heavy Metals XRF can be met; X ray light pipe 17 and detecting device 19 are individually fixed in above strainer.X ray light pipe 17 is connected by high voltage insulated cable with light pipe high-voltage power supply 18, and light pipe high-voltage power supply 18 is connected by data line with industrial PC 31.Detecting device 19 is connected with industrial PC 31 by data line, and the software that industrial PC 31 inside is installed can control X ray light pipe 17, light pipe high-voltage power supply 18 and detecting device 19 automatically, realizes the normal work of detection system.
The principle that X ray detects heavy metal element is as follows: x-ray bombardment is on sample, heavy metal element contained in sample can be excited, produce characteristic of correspondence fluorescence, fluorescent energy and Atom of Elements Z square are directly proportional, and the content of element to be measured is relevant with the feature X-fluorescence intensity of its transmitting; Digital signal by the built-in FPGA data processing circuit of detecting device 19 to gathering, amplify, after A/D conversion processes, and carries out data transmission by data-interface and industrial PC 31 and communicate with controlling.In analytic process, software can identify the spectrum peak of different heavy metal element automatically, and automatically smoothing, and the spectrogram process such as buckle back scape, whole spectrogram is presented on the screen of industrial PC 31 in real time.The data processing of this method adopts peak area method, by automatically identifying the characteristic peak of corresponding heavy metal, after carrying out buckle back scape, obtains clean peak intensity I
0 m, then after carrying out interference correction by software, new correction intensity I can be obtained
m.By the standard model of the corresponding heavy metal element of use, composed peak I accordingly
mdata; Get the sample of n heavy metal element different content, obtain one group of I
m(n), wherein n>=3; Draw I
mwith this concentration of element C in sample
mfunctional arrangement, obtain working curve.Heavy metal concentration (the C of enrichment on the relative intensity inverse strainer obtained in being detected by reality again
s).Again by above-mentioned formulae discovery C
l, namely obtain the concentration of heavy metal in water.This method is selected by the upgrading of software, light path hardware, can expand the quantitative test realizing the different elements such as cadmium, lead, arsenic, copper, chromium, zinc.
Strainer kinematic train comprises feeds belt wheel 20, take-up pulley 21, smoothly takes turns 22-25, pinch roller 26, transmission shaft 27, strainer 28.Strainer 28 is clamped, by forward and reverse rotation of transmission shaft 27 between pinch roller 26 and transmission shaft 27.Realize the transmission of strainer 28 between each system.Hello belt wheel 20, take-up pulley 21, transmission shaft 27 are connected with enrichment transmission control circuit plate 30, and enrichment transmission control circuit plate 30 is connected by data line with industrial PC 31, and the sequential of final strainer 28 moves control, by software control.
Control acquisition system and comprise water sample atomization control circuit board 29, enrichment transmission control circuit plate 30, industrial PC 31 and intelligent software.The collection of Various types of data in the automatic control of the process such as stream, circuit in total system and system, process and storage is realized by the software in industrial PC 31 and logical circuit.
Water quality heavy metal online analyzer based on XRF technology of the present invention and analytical approach comprise the following steps:
1) water sampling, atomization and example enrichment: first the first solenoid valve 6, second solenoid valve 7 is all in opening, water sample is squeezed in sample cell 2 by sampling pipe by sampling peristaltic pump 1, until after the liquid level in sample cell 2 detected by the first liquid level gauge 3, close sampling peristaltic pump 1 and stop sampling, close the first solenoid valve 6 again, guarantee the consistance of each sampling quantity.Then start ultrasonic atomizer 5 and start beginning primary atomization, air compressor 8 starts drive venturi scrubber 9 and is atomized further.Air-flow after atomization is by exsiccator 10, and removed by the water produced in aerosol particle, form dry particle, heavy metal substance can reside in Particle Phase.When atomization starts, open the 3rd solenoid valve 11, sampling pipe lifting motor 12 declines, and is clamped by strainer 28 between sample stage 13, forms confined space.Open sampling pump 16, synchronously carry out the example enrichment of dried particles thing.Flow controller 15 controls the gas circuit speed of evacuation, ensures the stability of sampling.Along with the liquid level in sample cell 2 drop to the second liquid level gauge 4 place time, ultrasonic atomizer 5, air compressor 8, second solenoid valve 7 first cuts out.(be generally set as 20s) after time delay certain hour, the 3rd solenoid valve 11, sampling pump 16 is closed successively.Sampling pipe lifting motor 12 rises.Complete the collection of sample, atomization and enrichment process.
2) water sample is discharged: after water sample atomization and enrichment complete, the first solenoid valve 6 and the second solenoid valve 7 are opened, and all liq in sample cell 2 is discharged by sampling peristaltic pump 1, completes this sampling, and evacuated tube road, prepare the collection of next water sample.
3) sample detection: the strainer completing enrichment, is run to by gearing and detects position, and industrial PC 31 controls to open light pipe high-voltage power supply 18, X ray light pipe 17 and XRF detecting device 19 automatically.Industrial PC 31 software completes the acquisition and processing of spectrogram, according to built-in working curve, finally can be calculated the concentration of corresponding heavy metal in water sample in conjunction with the data gathered.
Water quality heavy metal online analyzer based on XRF technology of the present invention and analytical approach are combined by the upgrading of software, light path hardware, K (potassium can be realized in theory, No. 19 elements)-U (uranium, No. 92 elements) etc. the expanded application of different heavy metal element, range of application is very extensive.
Water quality heavy metal online analyzer based on XRF technology of the present invention and analytical approach, detection for water quality heavy metal is limited to 1 μ about g/L, meets the requirement for limit value discharges such as lead, cadmium, mercury, arsenic, chromium, nickel, copper, zinc in water quality heavy metal in all existing national environmental standards.