CN114280187A - Method and equipment for detecting and analyzing benzene series in underground water of polluted site - Google Patents

Abstract

The invention discloses a method and equipment for detecting and analyzing benzene series in underground water of a polluted site, wherein the method comprises the following steps of S1: acquiring a water sample after determining a pollution treatment boundary and the height of the water level of underground water to obtain a sample to be detected; s2, adding a silver carbonate solution into the sample to be detected for reaction, and then filtering to obtain a pretreated sample; s3, heating the pretreated sample, placing the sample into a blowing and trapping device for blowing, collecting the blown gas through a trapping material, and finally heating the trapping material to obtain a resolved gas; s4, introducing the analytic gas into a gas chromatography mass spectrometer for qualitative and quantitative analysis; the invention has reasonable design and high detection efficiency of the benzene series in the groundwater, and is suitable for mass popularization.

Description

Method and equipment for detecting and analyzing benzene series in underground water of polluted site

Technical Field

The invention relates to the technical field of research on benzene series in underground water, in particular to a method and equipment for detecting and analyzing the benzene series in the underground water of a polluted site.

Background

Benzene series (BTEX) includes benzene, toluene, ethylbenzene and xylene, which are organic compounds with high volatility, high mobility and high toxicity. At present, with the development of industrial production, benzene series, especially benzene and toluene xylene, are widely used as solvents and basic chemical raw materials for grease, rubber, resin, paint and the like, so that discharged wastewater in the industries of petrochemical industry, pesticide, organic chemical industry, coking chemical industry and the like contains more benzene series, and becomes an important source of organic pollutants such as rivers, air, underground drinking water and the like.

Monocyclic aromatic hydrocarbons are generally colorless volatile liquids whose vapor is heavier than air, are poorly soluble in water and are readily soluble in organic solvents, and in liquid form, they have a specific gravity of less than 1 and are toxic. Benzene is a carcinogen, other benzene series substances have toxicity to human bodies and aquatic organisms in different degrees, and the substances can cause acute or chronic toxic effects to human bodies, and some substances are even related to tumors. Therefore, 6 benzene series of benzene, toluene, ethylbenzene, paraxylene, metaxylene and orthoxylene are listed in the blacklist of water environment priority control pollutants in China. In recent years, the influence of toxic and harmful organic pollutants on human health and living environment is becoming more serious, and particularly, benzene series matters are more important, so that the significance of monitoring the benzene series matters in the water environment is very important.

Disclosure of Invention

Aiming at the technical problems, the invention provides a method and equipment for detecting and analyzing benzene series in underground water of a polluted site.

The technical scheme of the invention is as follows: a method for detecting and analyzing benzene series in underground water of a polluted site comprises the following steps:

s1, sampling

S1-1, determining a pollution treatment boundary of a pollution site and the height of a groundwater level, and then equidistantly setting a plurality of groundwater sampling points in an internal area of the pollution treatment boundary;

s1-2, drilling pumping wells at different depths at each underground water sampling point according to the underground water level height obtained in the step S1-1, and then pumping underground water in each pumping well to obtain a sample to be detected;

s2 sample pretreatment

Adding a silver carbonate solution with the mass concentration of 15-35% into the sample to be detected obtained in the step S1-2, fully stirring to obtain a reaction solution, and then filtering the reaction solution by using a filter membrane with the pore diameter of 0.30-0.45 mu m to obtain a pretreated sample; wherein the volume ratio of the silver carbonate solution to the sample to be detected is 1: 9-16;

s3, extracting benzene series

S3-1, heating the pretreated sample obtained in the step S2 to 40-90 ℃, then placing the sample into a purging and trapping device, purging the heated pretreated sample by using nitrogen, and collecting the purged gas through a trapping material in the purging and trapping device to obtain a trapping material after trapping the gas; wherein the purging flow of the purging and trapping equipment is controlled to be 15-35 mL/min, and the purging temperature is controlled to be 80-120 ℃;

s3-2, heating the trapping material subjected to gas trapping obtained in the step S3-1 to 260-450 ℃ to obtain a resolved gas;

s4, detection analysis

Introducing the analysis gas obtained in the step S3-2 into a gas chromatography mass spectrometer for qualitative and quantitative analysis, wherein the chromatographic column is a DB-VRX quartz capillary column, and the tuning mode is DFTPP tuning; the chromatographic condition is that the carrier gas is high-purity helium gas, the flow rate is 1.2mL/min, split flow sampling is carried out at a ratio of 15:1, the temperature of a sample inlet is 230 ℃, the temperature of a column box is 40 ℃, the temperature raising program is kept for 2min at 40 ℃, and the temperature raising program is kept for 3min at 250 ℃ at the speed of 20 ℃/min; the mass spectrometry conditions are that the ion source temperature is 230 ℃, the interface temperature is 250 ℃, the solvent delay time is 0.5min, and the ion detection SCAN mode is adopted.

Further, in the step S1-2, before the sample to be detected is extracted, water pumping and well flushing are carried out on the water pumping well; the method specifically comprises the following steps: continuously draining for 10-25 min by using the maximum water yield of the pumping well; through carrying out well-flushing treatment to the pumping well, the benzene series content in the underground water tends to be stable, thereby improving the accuracy of the benzene series detection result in the underground water.

Further, after the step S2 is finished, adding an intermediate solvent with the volume of 20-35% of that of the pretreated sample, and uniformly mixing the mixture by shaking; the intermediate solvent is formed by mixing methanol and perylene-d 12 in equal volume; by adding the intermediate solvent formed by mixing methanol and perylene-d 12 into the pretreated sample, the stability and uniformity of the benzene series dispersion in the pretreated sample can be changed, so that the accuracy and precision of the detection and analysis method are improved.

Further, in the step S1-2, the depths of the pumping wells are arranged in an arithmetic progression, and the depths of the pumping wells are 8-15 m; by pumping the underground water with different depths, the interference of the content difference of the benzene series in the underground water with different depths on the detection and analysis result can be eliminated, and the accuracy of the detection and analysis result is improved.

Further, after the step S4 is completed, performing a blank standard addition experiment and a parallel experiment, wherein the relative percentage deviation of each compound in the blank standard addition experiment is less than 20%, and the recovery rate is 70-130%; the relative percentage deviation of the parallel experiment samples is less than 30%, and the matrix standard adding recovery rate of the water sample is 70-130%; by carrying out blank labeling experiments and parallel experiments, the influence of external environmental factors on detection and analysis results can be avoided, and the accuracy and the reliability of the detection and analysis results are ensured.

Further, after the step S2 is completed, introducing the pretreated sample into a quartz photolysis tube, and performing irradiation treatment on the quartz photolysis tube for 25-55 min by using a vacuum ultraviolet lamp with the wavelength of 85-165 nm; by carrying out photolysis treatment on the pretreated sample, inorganic halogen ions in the pretreated sample can be removed, and a good foundation is laid for sweeping and trapping benzene series in underground water.

The invention also provides detection and analysis equipment for benzene series in underground water of a polluted site, which comprises sampling equipment for collecting underground water samples, pretreatment equipment for pretreating samples to be detected, purging and trapping equipment for extracting the benzene series in the pretreated samples and a gas chromatography mass spectrometer for detecting and analyzing the benzene series in the underground water; the purging and trapping device comprises a device box, a purging component, a sample introduction component, a trapping component and a PLC (programmable logic controller); the lower end of the equipment box is provided with a base, the upper end of the equipment box is provided with an air inlet pipe and a sample inlet pipe, and the side wall of the equipment box is provided with a liquid discharge pipe; the purging component comprises a purging box, an air collecting sleeve, an air homogenizing disc and an air pump, the purging box is fixedly arranged at one end of the equipment box and communicated with the inside of the equipment box, a purging motor is arranged on the outer wall of the purging box, an output shaft of the purging motor penetrates through the purging box and is provided with an impeller, the air collecting sleeve is fixedly arranged at one side, close to the purging box, of the inside of the equipment box, the air homogenizing disc is sleeved inside the air collecting sleeve and communicated with an air inlet pipe, a plurality of air nozzles are uniformly distributed at one side, far away from the purging box, of the air homogenizing disc, the air pump is fixedly arranged on the base, and the output end of the air pump is communicated with the air inlet pipe; the sample injection assembly comprises a sample injection ring, a plurality of movable nozzles, a swinging component and a pressure pump, wherein the sample injection ring is movably clamped inside the equipment box, the sample injection ring is hollow and communicated with the sample injection pipe, the movable nozzles are uniformly distributed on the inner side of the sample injection ring and movably hinged with the sample injection ring, each movable nozzle is respectively connected and communicated with the sample injection ring through a hose, the swinging component is movably clamped inside the equipment box and used for adjusting the reciprocating swing of each movable nozzle, the pressure pump is fixedly arranged on the base, and the output end of the pressure pump is communicated with the sample injection pipe; the collecting component comprises a mounting sleeve and a collecting box, the mounting sleeve is fixedly arranged at the other end of the equipment box and extends into the equipment box, the collecting box is movably clamped inside the mounting sleeve, a plurality of exhaust holes are uniformly formed in the collecting box, and collecting materials are movably clamped inside the collecting box; the PLC controller is respectively and electrically connected with the air pump, the blowing motor and the pressure pump.

Furthermore, a polyacrylate solid-phase micro-extraction needle with the thickness of 55-75 mu m is adopted as a trapping material; so that the benzene series substances in the underground water can be trapped more comprehensively and thoroughly.

Furthermore, the swing component comprises a swing sleeve and a swing motor, the swing sleeve is rotatably clamped inside the equipment box through a connecting sleeve, each movable nozzle is provided with a movable shaft, the side wall of the swing sleeve is provided with an arc-shaped chute corresponding to each movable shaft, each movable shaft is respectively clamped in the arc-shaped chute at the corresponding position in a sliding manner, the lower end of the swing sleeve is provided with a gear groove, the swing motor is fixedly arranged inside the equipment box, an output shaft of the swing motor is provided with a driving gear, the driving gear is meshed with the gear groove and is electrically connected with the PLC; the swing motor drives the swing sleeve to swing in a reciprocating manner, so that each movable nozzle swings in a reciprocating manner in the sample injection ring, underground water samples on the inner side of the sample injection ring are distributed more uniformly, and the sweeping and trapping efficiency of the benzene series is improved.

Furthermore, a limit baffle is arranged at the joint of the trapping material and the trapping box; through setting up limit baffle, can improve the stability that entrapment material and entrapment box are connected to improve the effect of entrapment material.

Furthermore, 2-4 air inlet channels are arranged in the air homogenizing disc, the air inlet channels are communicated with one another, and the air nozzles correspond to the air inlet channels in position and are communicated with one another; through setting up a plurality of inlet channels, can improve each air jet nozzle air-jet homogeneity to improve benzene series thing in the groundwater and sweep efficiency.

The working principle of the sweeping and trapping device comprises the following steps:

s1, respectively connecting the air pump, the blowing motor and the pressure pump with an external power supply;

s2, controlling the air pump, the blowing motor and the pressurizing pump to be started through the PLC, pressurizing nitrogen by the air pump, introducing the pressurized nitrogen into the air homogenizing disc through the air inlet pipe, and ejecting the pressurized nitrogen through the air nozzle; the PLC controller is used for controlling the start of the purging motor, and the purging motor is used for driving the impeller to rotate so as to increase the flow velocity of the nitrogen;

s3, pressurizing the underground water sample by using a pressurizing pump, introducing the pressurized underground water sample into a sample injection ring through a sample injection pipe, ejecting the pressurized underground water sample through a movable nozzle, and moving the pressurized underground water sample towards the direction of a trapping box after the benzene series in the underground water is swept by the pressurized nitrogen;

s4, adsorbing the benzene series substances blown out by the nitrogen by utilizing the trapping material in the trapping box; after adsorption is finished, removing the trapping material and carrying out the next detection; the purged groundwater sample is drained out of the apparatus box through a drain pipe.

Compared with the prior art, the beneficial effects of the invention are embodied in the following points:

firstly, the method detects and analyzes the benzene series in the underground water of the polluted site by utilizing sweeping and trapping combined with gas chromatography-mass spectrometry, has the advantages of low detection limit, high detection sensitivity and high accuracy, and has promotion significance for treating underground water pollution;

secondly, in the sampling process, by collecting underground water samples at different depths and simultaneously removing inorganic halogen ions in the collected underground water samples, the interference of external environmental factors on detection and analysis results is reduced, and the accuracy of the detection and analysis results is improved;

thirdly, the sweeping and trapping device can blow off the benzene series volatilized from the underground water sample to the maximum extent, and creates good conditions for gas chromatography-mass spectrometry detection and analysis.

Drawings

FIG. 1 is a longitudinal section of the purge trap apparatus of the present invention;

FIG. 2 is a top view of the purge and trap apparatus of the present invention;

FIG. 3 is a schematic view of the internal structure of the gas distribution plate of the present invention;

FIG. 4 is a schematic view of the connection of the oscillating sleeve of the present invention to a movable nozzle;

FIG. 5 is a schematic view of the construction of the wobble sleeve of the present invention;

the device comprises a device box 1, a base 10, an air inlet pipe 11, a sample inlet pipe 12, a liquid discharge pipe 13, a purging component 2, a purging box 20, a gas collecting sleeve 21, a gas homogenizing disc 22, an air nozzle 220, an air inlet channel 221, an air pump 23, a purging motor 24, an impeller 240, a sample inlet component 3, a sample injection ring 30, a movable nozzle 31, a movable shaft 310, a swinging component 32, a swinging sleeve 320, a swinging motor 321, a driving gear 3210, a connecting sleeve 322, an arc-shaped chute 323, a gear groove 324, a pressurizing pump 33, a trapping component 4, a mounting sleeve 40, a trapping box 41 and a limit baffle 42.

Detailed Description

Example 1

A method for detecting and analyzing benzene series in underground water of a polluted site comprises the following steps:

s1, sampling

S1-1, determining a pollution treatment boundary of a pollution site and the height of a groundwater level, and then equidistantly setting a plurality of groundwater sampling points in an internal area of the pollution treatment boundary;

s1-2, drilling pumping wells at different depths at each underground water sampling point according to the underground water level height obtained in the step S1-1, and then pumping underground water in each pumping well to obtain a sample to be detected;

s2 sample pretreatment

Adding a silver carbonate solution with the mass concentration of 15% into the sample to be detected obtained in the step S1-2, fully stirring to obtain a reaction solution, and then filtering the reaction solution by using a filter membrane with the pore diameter of 0.30 mu m to obtain a pretreated sample; wherein the volume ratio of the silver carbonate solution to the sample to be detected is 1: 9;

s3, extracting benzene series

S3-1, heating the pretreated sample obtained in the step S2 to 40 ℃, then placing the sample into a purging and trapping device, purging the heated pretreated sample by using nitrogen, and collecting the purged gas through a trapping material in the purging and trapping device to obtain a trapping material after trapping the gas; wherein, the purging flow of the purging and trapping equipment is controlled to be 15mL/min, and the purging temperature is 80 ℃;

s3-2, heating the trapping material subjected to the gas trapping obtained in the step S3-1 to 260 ℃ to obtain a resolved gas;

s4, detection analysis

Introducing the analysis gas obtained in the step S3-2 into a gas chromatography mass spectrometer for qualitative and quantitative analysis, wherein the chromatographic column is a DB-VRX quartz capillary column, and the tuning mode is DFTPP tuning; the chromatographic condition is that the carrier gas is high-purity helium gas, the flow rate is 1.2mL/min, split flow sampling is carried out at a ratio of 15:1, the temperature of a sample inlet is 230 ℃, the temperature of a column box is 40 ℃, the temperature raising program is kept for 2min at 40 ℃, and the temperature raising program is kept for 3min at 250 ℃ at the speed of 20 ℃/min; the mass spectrometry conditions are that the ion source temperature is 230 ℃, the interface temperature is 250 ℃, the solvent delay time is 0.5min, and the ion detection SCAN mode is adopted.

Example 2

The embodiment describes detection and analysis equipment for benzene series in underground water of a polluted site, which is suitable for the detection and analysis equipment of the benzene series in the underground water of the polluted site in the embodiment 1, and comprises sampling equipment for collecting an underground water sample, pretreatment equipment for pretreating a sample to be detected, ultrafiltration membrane filtration equipment in the prior art, purging and trapping equipment for extracting the benzene series in the pretreated sample, and a gas chromatography mass spectrometer for detecting and analyzing the benzene series in the underground water; the sweeping and trapping device comprises a device box 1, a sweeping component 2, a sample introduction component 3, a trapping component 4 and a PLC (programmable logic controller); the lower end of the equipment box 1 is provided with a base 10, the upper end is provided with an air inlet pipe 11 and a sample inlet pipe 12, and the side wall is provided with a liquid discharge pipe 13; the purging component 2 comprises a purging box 20, an air collecting sleeve 21, an air homogenizing disc 22 and an air pump 23, the purging box 20 is fixedly arranged at one end of the equipment box 1 and communicated with the inside of the equipment box 1, a purging motor 24 is arranged on the outer wall of the purging box 20, an output shaft of the purging motor 24 penetrates through the purging box 20 and is provided with an impeller 240, the air collecting sleeve 21 is fixedly arranged at one side, close to the purging box 20, of the inside of the equipment box 1, the air homogenizing disc 22 is sleeved inside the air collecting sleeve 21 and communicated with the air inlet pipe 11, a plurality of air nozzles 220 are uniformly distributed at one side, far away from the purging box 20, of the air homogenizing disc 22, the air pump 23 is fixedly arranged on the base 10, and the output end of the air pump 23 is communicated with the air inlet pipe 11; the sample introduction assembly 3 comprises a sample introduction ring 30, movable nozzles 31, swing members 32 and a pressure pump 33, wherein the sample introduction ring 30 is movably clamped inside the equipment box 1, the sample introduction ring 30 is hollow and communicated with the sample introduction pipe 12, the number of the movable nozzles 31 is 8, each movable nozzle 31 is uniformly distributed on the inner side of the sample introduction ring 30 and movably hinged with the sample introduction ring 30, each movable nozzle 31 is respectively connected and communicated with the sample introduction ring 30 through a hose, the swing members 32 are movably clamped inside the equipment box 1 and used for adjusting the reciprocating swing of each movable nozzle 31, the pressure pump 33 is fixedly arranged on the base 10, and the output end of the pressure pump 33 is communicated with the sample introduction pipe 12; the collecting component 4 comprises an installation sleeve 40 and a collecting box 41, the installation sleeve 40 is fixedly arranged at the other end of the equipment box 1 and extends into the equipment box 1, the collecting box 41 is movably clamped inside the installation sleeve 40, a plurality of exhaust holes are uniformly formed in the collecting box 41, and collecting materials are movably clamped inside the collecting box 41; the PLC is respectively and electrically connected with the air pump 23, the purging motor 24 and the pressure pump 33; the PLC controller, the air pump 23, the blowing motor 24 and the pressurizing pump 33 are all commercially available products.

Example 3

A method for detecting and analyzing benzene series in underground water of a polluted site comprises the following steps:

s1, sampling

S1-1, determining a pollution treatment boundary of a pollution site and the height of a groundwater level, and then equidistantly setting a plurality of groundwater sampling points in an internal area of the pollution treatment boundary;

s1-2, drilling pumping wells at different depths at each underground water sampling point according to the underground water level obtained in the step S1-1, and performing pumping and well washing treatment on the pumping wells; the method specifically comprises the following steps: continuously draining for 10min by using the maximum water yield of the pumping well; finally, pumping underground water in each pumping well to obtain a sample to be detected; wherein the depths of the pumping wells are arranged in an arithmetic progression, and the depths of the pumping wells are 8 m;

s2 sample pretreatment

Adding a 23% silver carbonate solution in mass concentration into the sample to be detected obtained in the step S1-2, fully stirring to obtain a reaction solution, and then filtering the reaction solution by using a filter membrane with the pore diameter of 0.41 mu m to obtain a pretreated sample; wherein the volume ratio of the silver carbonate solution to the sample to be detected is 1: 12;

s3, extracting benzene series

S3-1, heating the pretreated sample obtained in the step S2 to 69 ℃, then placing the sample into a purging and trapping device, purging the heated pretreated sample by using nitrogen, and collecting the purged gas through a trapping material in the purging and trapping device to obtain a trapping material after trapping the gas; wherein the purging flow of the purging and trapping equipment is controlled to be 26mL/min, and the purging temperature is controlled to be 105 ℃;

s3-2, heating the trapping material subjected to gas trapping obtained in the step S3-1 to 380 ℃ to obtain a resolved gas;

s4, detection analysis

Introducing the analysis gas obtained in the step S3-2 into a gas chromatography mass spectrometer for qualitative and quantitative analysis, wherein the chromatographic column is a DB-VRX quartz capillary column, and the tuning mode is DFTPP tuning; the chromatographic condition is that the carrier gas is high-purity helium gas, the flow rate is 1.2mL/min, split flow sampling is carried out at a ratio of 15:1, the temperature of a sample inlet is 230 ℃, the temperature of a column box is 40 ℃, the temperature raising program is kept for 2min at 40 ℃, and the temperature raising program is kept for 3min at 250 ℃ at the speed of 20 ℃/min; the mass spectrometry conditions are that the ion source temperature is 230 ℃, the interface temperature is 250 ℃, the solvent delay time is 0.5min, and the ion detection SCAN mode is adopted.

Example 4

The embodiment describes detection and analysis equipment for benzene series in underground water of a polluted site, which is suitable for the detection and analysis equipment of the benzene series in the underground water of the polluted site in the embodiment 3, and comprises sampling equipment for collecting an underground water sample, pretreatment equipment for pretreating a sample to be detected, ultrafiltration membrane filtration equipment in the prior art, purging and trapping equipment for extracting the benzene series in the pretreated sample, and a gas chromatography mass spectrometer for detecting and analyzing the benzene series in the underground water; the sweeping and trapping device comprises a device box 1, a sweeping component 2, a sample introduction component 3, a trapping component 4 and a PLC (programmable logic controller); the lower end of the equipment box 1 is provided with a base 10, the upper end is provided with an air inlet pipe 11 and a sample inlet pipe 12, and the side wall is provided with a liquid discharge pipe 13; the purging component 2 comprises a purging box 20, an air collecting sleeve 21, an air homogenizing disc 22 and an air pump 23, the purging box 20 is fixedly arranged at one end of the equipment box 1 and communicated with the inside of the equipment box 1, a purging motor 24 is arranged on the outer wall of the purging box 20, an output shaft of the purging motor 24 penetrates through the purging box 20 and is provided with an impeller 240, the air collecting sleeve 21 is fixedly arranged at one side, close to the purging box 20, of the inside of the equipment box 1, the air homogenizing disc 22 is sleeved inside the air collecting sleeve 21 and communicated with the air inlet pipe 11, a plurality of air nozzles 220 are uniformly distributed at one side, far away from the purging box 20, of the air homogenizing disc 22, the air pump 23 is fixedly arranged on the base 10, and the output end of the air pump 23 is communicated with the air inlet pipe 11; the sample introduction assembly 3 comprises a sample introduction ring 30, movable nozzles 31, swing members 32 and a pressure pump 33, wherein the sample introduction ring 30 is movably clamped inside the equipment box 1, the sample introduction ring 30 is hollow and communicated with the sample introduction pipe 12, the number of the movable nozzles 31 is 8, each movable nozzle 31 is uniformly distributed on the inner side of the sample introduction ring 30 and movably hinged with the sample introduction ring 30, each movable nozzle 31 is respectively connected and communicated with the sample introduction ring 30 through a hose, the swing members 32 are movably clamped inside the equipment box 1 and used for adjusting the reciprocating swing of each movable nozzle 31, the pressure pump 33 is fixedly arranged on the base 10, and the output end of the pressure pump 33 is communicated with the sample introduction pipe 12; the collecting component 4 comprises a mounting sleeve 40 and a collecting box 41, the mounting sleeve 40 is fixedly arranged at the other end of the equipment box 1 and extends into the equipment box 1, the collecting box 41 is movably clamped inside the mounting sleeve 40, a plurality of exhaust holes are uniformly formed in the collecting box 41, a collecting material is movably clamped inside the collecting box 41, and the collecting material is a polyacrylate solid-phase micro-extraction needle with the thickness of 65 micrometers; the trapping of the benzene series in the underground water is more comprehensive and thorough; a limiting baffle 42 is arranged at the joint of the trapping material and the trapping box 41; the limiting baffle 42 can improve the stability of the connection of the trapping material and the trapping box 41, thereby improving the effect of the trapping material; the PLC is respectively and electrically connected with the air pump 23, the purging motor 24 and the pressure pump 33; the PLC controller, the air pump 23, the blowing motor 24 and the pressurizing pump 33 are all commercially available products.

Example 5

A method for detecting and analyzing benzene series in underground water of a polluted site comprises the following steps:

s1, sampling

S1-1, determining a pollution treatment boundary of a pollution site and the height of a groundwater level, and then equidistantly setting a plurality of groundwater sampling points in an internal area of the pollution treatment boundary;

s1-2, drilling pumping wells at different depths at each underground water sampling point according to the underground water level height obtained in the step S1-1, and then pumping underground water in each pumping well to obtain a sample to be detected;

s2 sample pretreatment

Adding a 35% silver carbonate solution into the sample to be detected obtained in the step S1-2, fully stirring to obtain a reaction solution, and then filtering the reaction solution by using a filter membrane with the pore diameter of 0.45 mu m to obtain a pretreated sample; wherein the volume ratio of the silver carbonate solution to the sample to be detected is 1: 16; adding an intermediate solvent with the volume of 20% of that of the pretreated sample, and uniformly mixing the mixture by shaking; the intermediate solvent is formed by mixing methanol and perylene-d 12 in equal volume;

s3, extracting benzene series

S3-1, heating the pretreated sample processed in the step S2 to 90 ℃, then placing the sample into a purging and trapping device, purging the heated pretreated sample by using nitrogen, and collecting the purged gas through a trapping material in the purging and trapping device to obtain a trapping material after trapping the gas; wherein the purging flow of the purging and trapping equipment is controlled to be 35mL/min, and the purging temperature is controlled to be 120 ℃;

s3-2, heating the trapping material subjected to the gas trapping obtained in the step S3-1 to 450 ℃ to obtain a resolved gas;

s4, detection analysis

Introducing the analysis gas obtained in the step S3-2 into a gas chromatography mass spectrometer for qualitative and quantitative analysis, wherein the chromatographic column is a DB-VRX quartz capillary column, and the tuning mode is DFTPP tuning; the chromatographic condition is that the carrier gas is high-purity helium gas, the flow rate is 1.2mL/min, split flow sampling is carried out at a ratio of 15:1, the temperature of a sample inlet is 230 ℃, the temperature of a column box is 40 ℃, the temperature raising program is kept for 2min at 40 ℃, and the temperature raising program is kept for 3min at 250 ℃ at the speed of 20 ℃/min; the mass spectrometry conditions are that the ion source temperature is 230 ℃, the interface temperature is 250 ℃, the solvent delay time is 0.5min, and the ion detection SCAN mode is adopted.

Example 6

The embodiment describes detection and analysis equipment for benzene series in underground water of a polluted site, which is suitable for the detection and analysis equipment of the benzene series in the underground water of the polluted site in the embodiment 5, and comprises sampling equipment for collecting an underground water sample, pretreatment equipment for pretreating a sample to be detected, ultrafiltration membrane filtration equipment in the prior art, purging and trapping equipment for extracting the benzene series in the pretreated sample, and a gas chromatography mass spectrometer for detecting and analyzing the benzene series in the underground water; the sweeping and trapping device comprises a device box 1, a sweeping component 2, a sample introduction component 3, a trapping component 4 and a PLC (programmable logic controller); the lower end of the equipment box 1 is provided with a base 10, the upper end is provided with an air inlet pipe 11 and a sample inlet pipe 12, and the side wall is provided with a liquid discharge pipe 13; the purging component 2 comprises a purging box 20, an air collecting sleeve 21, an air homogenizing disc 22 and an air pump 23, the purging box 20 is fixedly arranged at one end of the equipment box 1 and communicated with the inside of the equipment box 1, a purging motor 24 is arranged on the outer wall of the purging box 20, an output shaft of the purging motor 24 penetrates through the purging box 20 and is provided with an impeller 240, the air collecting sleeve 21 is fixedly arranged at one side, close to the purging box 20, of the inside of the equipment box 1, the air homogenizing disc 22 is sleeved inside the air collecting sleeve 21 and communicated with the air inlet pipe 11, a plurality of air nozzles 220 are uniformly distributed at one side, far away from the purging box 20, of the air homogenizing disc 22, the air pump 23 is fixedly arranged on the base 10, and the output end of the air pump 23 is communicated with the air inlet pipe 11; the sample feeding assembly 3 comprises a sample feeding ring 30, movable nozzles 31, a swinging member 32 and a pressure pump 33, wherein the sample feeding ring 30 is movably clamped inside the equipment box 1, the sample feeding ring 30 is hollow and communicated with the sample feeding pipe 12, the number of the movable nozzles 31 is 8, each movable nozzle 31 is uniformly distributed on the inner side of the sample feeding ring 30 and movably hinged with the sample feeding ring 30, each movable nozzle 31 is respectively communicated with the sample feeding ring 30 through a hose, the swinging member 32 comprises a swinging sleeve 320 and a swinging motor 321, the swinging sleeve 320 is rotatably clamped inside the equipment box 1 through a connecting sleeve 322, each movable nozzle 31 is provided with a movable shaft 310, the side wall of the swinging sleeve 320 is provided with an arc chute 323 corresponding to each movable shaft 310, each movable shaft 310 is respectively clamped in the arc chute 323 corresponding to the position in a sliding manner, the lower end of the swinging sleeve 320 is provided with a gear groove 324, the swinging motor 321 is fixedly arranged inside the equipment box 1, a driving gear 3210 is arranged on an output shaft of the swing motor 321, the driving gear 3210 is meshed with the gear groove 324, and the swing motor 321 is electrically connected with the PLC controller; the swing motor 321 drives the swing sleeve 320 to swing in a reciprocating manner, so that each movable nozzle 31 swings in a reciprocating manner in the sample injection ring 30, underground water samples inside the sample injection ring 30 are distributed more uniformly, the sweeping and trapping efficiency of benzene series is improved, the pressure pump 33 is fixedly arranged on the base 10, and the output end of the pressure pump 33 is communicated with the sample injection pipe 12; the collecting component 4 comprises an installation sleeve 40 and a collecting box 41, the installation sleeve 40 is fixedly arranged at the other end of the equipment box 1 and extends into the equipment box 1, the collecting box 41 is movably clamped inside the installation sleeve 40, a plurality of exhaust holes are uniformly formed in the collecting box 41, and collecting materials are movably clamped inside the collecting box 41; the PLC is respectively and electrically connected with the air pump 23, the blowing motor 24, the swing motor 321 and the pressure pump 33; the PLC controller, the air pump 23, the blowing motor 24, the swing motor 321 and the pressure pump 33 are all commercially available products.

Example 7

A method for detecting and analyzing benzene series in underground water of a polluted site comprises the following steps:

s1, sampling

S1-1, determining a pollution treatment boundary of a pollution site and the height of a groundwater level, and then equidistantly setting a plurality of groundwater sampling points in an internal area of the pollution treatment boundary;

s1-2, drilling pumping wells at different depths at each underground water sampling point according to the underground water level height obtained in the step S1-1, and then pumping underground water in each pumping well to obtain a sample to be detected;

s2 sample pretreatment

Adding a silver carbonate solution with the mass concentration of 15% into the sample to be detected obtained in the step S1-2, fully stirring to obtain a reaction solution, and then filtering the reaction solution by using a filter membrane with the pore diameter of 0.30 mu m to obtain a pretreated sample; wherein the volume ratio of the silver carbonate solution to the sample to be detected is 1: 9;

s3, extracting benzene series

S3-1, heating the pretreated sample obtained in the step S2 to 40 ℃, then placing the sample into a purging and trapping device, purging the heated pretreated sample by using nitrogen, and collecting the purged gas through a trapping material in the purging and trapping device to obtain a trapping material after trapping the gas; wherein, the purging flow of the purging and trapping equipment is controlled to be 15mL/min, and the purging temperature is 80 ℃;

s3-2, heating the trapping material subjected to the gas trapping obtained in the step S3-1 to 260 ℃ to obtain a resolved gas;

s4, detection analysis

Introducing the analysis gas obtained in the step S3-2 into a gas chromatography mass spectrometer for qualitative and quantitative analysis, wherein the chromatographic column is a DB-VRX quartz capillary column, and the tuning mode is DFTPP tuning; the chromatographic condition is that the carrier gas is high-purity helium gas, the flow rate is 1.2mL/min, split flow sampling is carried out at a ratio of 15:1, the temperature of a sample inlet is 230 ℃, the temperature of a column box is 40 ℃, the temperature raising program is kept for 2min at 40 ℃, and the temperature raising program is kept for 3min at 250 ℃ at the speed of 20 ℃/min; the mass spectrometry conditions are that the ion source temperature is 230 ℃, the interface temperature is 250 ℃, the solvent delay time is 0.5min, and an ion detection SCAN mode is adopted; finally, carrying out a blank standard adding experiment and a parallel experiment, wherein the relative percentage deviation of each compound in the blank standard adding experiment is less than 20%, and the recovery rate is 70-130%; the relative percentage deviation of the parallel experiment samples is less than 30%, and the matrix standard adding recovery rate of the water sample is 70-130%.

Example 8

The embodiment describes detection and analysis equipment for benzene series in underground water of a polluted site, which is suitable for the detection and analysis equipment of the benzene series in the underground water of the polluted site in the embodiment 7, and comprises sampling equipment for collecting an underground water sample, pretreatment equipment for pretreating a sample to be detected, ultrafiltration membrane filtration equipment in the prior art, purging and trapping equipment for extracting the benzene series in the pretreated sample, and a gas chromatography mass spectrometer for detecting and analyzing the benzene series in the underground water; the sweeping and trapping device comprises a device box 1, a sweeping component 2, a sample introduction component 3, a trapping component 4 and a PLC (programmable logic controller); the lower end of the equipment box 1 is provided with a base 10, the upper end is provided with an air inlet pipe 11 and a sample inlet pipe 12, and the side wall is provided with a liquid discharge pipe 13; the blowing component 2 comprises a blowing box 20, an air collecting sleeve 21, an air homogenizing disc 22 and an air pump 23, the blowing box 20 is fixedly arranged at one end of the equipment box 1 and communicated with the inside of the equipment box 1, a blowing motor 24 is arranged on the outer wall of the blowing box 20, an output shaft of the blowing motor 24 penetrates through the blowing box 20 and is provided with an impeller 240, the air collecting sleeve 21 is fixedly arranged at one side, close to the blowing box 20, of the inside of the equipment box 1, the air homogenizing disc 22 is sleeved inside the air collecting sleeve 21 and is communicated with the air inlet pipe 11, a plurality of air nozzles 220 are uniformly distributed at one side, far away from the blowing box 20, of the air homogenizing disc 22, 3 air inlet flow channels 221 are arranged inside the air homogenizing disc 22, the air inlet flow channels 221 are communicated with one another, and the air nozzles 220 correspond to the positions of the air inlet flow channels 221 and are communicated with one another; by arranging the plurality of air inlet channels 221, the uniformity of air injection of each air nozzle 220 can be improved, so that the sweeping efficiency of the benzene series in the underground water is improved; the air pump 23 is fixedly arranged on the base 10, and the output end of the air pump 23 is communicated with the air inlet pipe 11; the sample feeding assembly 3 comprises a sample feeding ring 30, movable nozzles 31, a swinging member 32 and a pressure pump 33, wherein the sample feeding ring 30 is movably clamped inside the equipment box 1, the sample feeding ring 30 is hollow and communicated with the sample feeding pipe 12, the number of the movable nozzles 31 is 8, each movable nozzle 31 is uniformly distributed on the inner side of the sample feeding ring 30 and movably hinged with the sample feeding ring 30, each movable nozzle 31 is respectively communicated with the sample feeding ring 30 through a hose, the swinging member 32 comprises a swinging sleeve 320 and a swinging motor 321, the swinging sleeve 320 is rotatably clamped inside the equipment box 1 through a connecting sleeve 322, each movable nozzle 31 is provided with a movable shaft 310, the side wall of the swinging sleeve 320 is provided with an arc chute 323 corresponding to each movable shaft 310, each movable shaft 310 is respectively clamped in the arc chute 323 corresponding to the position in a sliding manner, the lower end of the swinging sleeve 320 is provided with a gear groove 324, the swinging motor 321 is fixedly arranged inside the equipment box 1, a driving gear 3210 is arranged on an output shaft of the swing motor 321, the driving gear 3210 is meshed with the gear groove 324, and the swing motor 321 is electrically connected with the PLC controller; the swing motor 321 drives the swing sleeve 320 to swing in a reciprocating manner, so that each movable nozzle 31 swings in a reciprocating manner in the sample injection ring 30, underground water samples on the inner side of the sample injection ring 30 are distributed more uniformly, and the sweeping and trapping efficiency of the benzene series is improved; the pressure pump 33 is fixedly arranged on the base 10, and the output end of the pressure pump 33 is communicated with the sampling pipe 12; the collecting component 4 comprises a mounting sleeve 40 and a collecting box 41, the mounting sleeve 40 is fixedly arranged at the other end of the equipment box 1 and extends into the equipment box 1, the collecting box 41 is movably clamped inside the mounting sleeve 40, a plurality of exhaust holes are uniformly formed in the collecting box 41, a collecting material is movably clamped inside the collecting box 41, and the collecting material is a polyacrylate solid-phase micro-extraction needle with the thickness of 65 micrometers; a limiting baffle 42 is arranged at the joint of the trapping material and the trapping box 41; the limiting baffle 42 can improve the stability of the connection of the trapping material and the trapping box 41, thereby improving the effect of the trapping material; the PLC is respectively and electrically connected with the air pump 23, the blowing motor 24, the swing motor 321 and the pressure pump 33; the PLC controller, the air pump 23, the blowing motor 24, the swing motor 321 and the pressure pump 33 are all commercially available products.

Example 9

A method for detecting and analyzing benzene series in underground water of a polluted site comprises the following steps:

s1, sampling

S1-1, determining a pollution treatment boundary of a pollution site and the height of a groundwater level, and then equidistantly setting a plurality of groundwater sampling points in an internal area of the pollution treatment boundary;

s1-2, drilling pumping wells at different depths at each underground water sampling point according to the underground water level height obtained in the step S1-1, and then pumping underground water in each pumping well to obtain a sample to be detected;

s2 sample pretreatment

Adding a 35% silver carbonate solution into the sample to be detected obtained in the step S1-2, fully stirring to obtain a reaction solution, and then filtering the reaction solution by using a filter membrane with the pore diameter of 0.45 mu m to obtain a pretreated sample; wherein the volume ratio of the silver carbonate solution to the sample to be detected is 1: 16; introducing the pretreated sample into a quartz photolysis tube, and irradiating the quartz photolysis tube for 25min by using a vacuum ultraviolet lamp with the wavelength of 85 nm;

s3, extracting benzene series

S3-1, heating the pretreated sample obtained in the step S2 to 90 ℃, then placing the sample into a purging and trapping device, purging the heated pretreated sample by using nitrogen, and collecting the purged gas through a trapping material in the purging and trapping device to obtain a trapping material after trapping the gas; wherein, the purging flow of the purging and trapping equipment is controlled to be 15mL/min, and the purging temperature is 80 ℃;

s3-2, heating the trapping material subjected to the gas trapping obtained in the step S3-1 to 260 ℃ to obtain a resolved gas;

s4, detection analysis

Introducing the analysis gas obtained in the step S3-2 into a gas chromatography mass spectrometer for qualitative and quantitative analysis, wherein the chromatographic column is a DB-VRX quartz capillary column, and the tuning mode is DFTPP tuning; the chromatographic condition is that the carrier gas is high-purity helium gas, the flow rate is 1.2mL/min, split flow sampling is carried out at a ratio of 15:1, the temperature of a sample inlet is 230 ℃, the temperature of a column box is 40 ℃, the temperature raising program is kept for 2min at 40 ℃, and the temperature raising program is kept for 3min at 250 ℃ at the speed of 20 ℃/min; the mass spectrometry conditions are that the ion source temperature is 230 ℃, the interface temperature is 250 ℃, the solvent delay time is 0.5min, and the ion detection SCAN mode is adopted.

Example 10

The embodiment describes detection and analysis equipment for benzene series in underground water of a polluted site, which is suitable for the detection and analysis equipment of the benzene series in the underground water of the polluted site in the embodiment 9, and comprises sampling equipment for collecting an underground water sample, pretreatment equipment for pretreating a sample to be detected, ultrafiltration membrane filtration equipment in the prior art, purging and trapping equipment for extracting the benzene series in the pretreated sample, and a gas chromatography mass spectrometer for detecting and analyzing the benzene series in the underground water; the sweeping and trapping device comprises a device box 1, a sweeping component 2, a sample introduction component 3, a trapping component 4 and a PLC (programmable logic controller); the lower end of the equipment box 1 is provided with a base 10, the upper end is provided with an air inlet pipe 11 and a sample inlet pipe 12, and the side wall is provided with a liquid discharge pipe 13; the blowing component 2 comprises a blowing box 20, an air collecting sleeve 21, an air homogenizing disc 22 and an air pump 23, the blowing box 20 is fixedly arranged at one end of the equipment box 1 and communicated with the inside of the equipment box 1, a blowing motor 24 is arranged on the outer wall of the blowing box 20, an output shaft of the blowing motor 24 penetrates through the blowing box 20 and is provided with an impeller 240, the air collecting sleeve 21 is fixedly arranged at one side, close to the blowing box 20, of the inside of the equipment box 1, the air homogenizing disc 22 is sleeved inside the air collecting sleeve 21 and is communicated with the air inlet pipe 11, a plurality of air nozzles 220 are uniformly distributed at one side, far away from the blowing box 20, of the air homogenizing disc 22, 3 air inlet flow channels 221 are arranged inside the air homogenizing disc 22, the air inlet flow channels 221 are communicated with one another, and the air nozzles 220 correspond to the positions of the air inlet flow channels 221 and are communicated with one another; by arranging the plurality of air inlet channels 221, the uniformity of air injection of each air nozzle 220 can be improved, so that the sweeping efficiency of the benzene series in the underground water is improved; the air pump 23 is fixedly arranged on the base 10, and the output end of the air pump 23 is communicated with the air inlet pipe 11; the sample feeding assembly 3 comprises a sample feeding ring 30, movable nozzles 31, a swinging member 32 and a pressure pump 33, wherein the sample feeding ring 30 is movably clamped inside the equipment box 1, the sample feeding ring 30 is hollow and communicated with the sample feeding pipe 12, the number of the movable nozzles 31 is 8, each movable nozzle 31 is uniformly distributed on the inner side of the sample feeding ring 30 and movably hinged with the sample feeding ring 30, each movable nozzle 31 is respectively communicated with the sample feeding ring 30 through a hose, the swinging member 32 comprises a swinging sleeve 320 and a swinging motor 321, the swinging sleeve 320 is rotatably clamped inside the equipment box 1 through a connecting sleeve 322, each movable nozzle 31 is provided with a movable shaft 310, the side wall of the swinging sleeve 320 is provided with an arc chute 323 corresponding to each movable shaft 310, each movable shaft 310 is respectively clamped in the arc chute 323 corresponding to the position in a sliding manner, the lower end of the swinging sleeve 320 is provided with a gear groove 324, the swinging motor 321 is fixedly arranged inside the equipment box 1, a driving gear 3210 is arranged on an output shaft of the swing motor 321, the driving gear 3210 is meshed with the gear groove 324, and the swing motor 321 is electrically connected with the PLC controller; the swing motor 321 drives the swing sleeve 320 to swing in a reciprocating manner, so that each movable nozzle 31 swings in a reciprocating manner in the sample injection ring 30, underground water samples on the inner side of the sample injection ring 30 are distributed more uniformly, and the sweeping and trapping efficiency of the benzene series is improved; the pressure pump 33 is fixedly arranged on the base 10, and the output end of the pressure pump 33 is communicated with the sampling pipe 12; the collecting component 4 comprises a mounting sleeve 40 and a collecting box 41, the mounting sleeve 40 is fixedly arranged at the other end of the equipment box 1 and extends into the equipment box 1, the collecting box 41 is movably clamped inside the mounting sleeve 40, a plurality of exhaust holes are uniformly formed in the collecting box 41, a collecting material is movably clamped inside the collecting box 41, and the collecting material is a polyacrylate solid-phase micro-extraction needle with the thickness of 75 micrometers; a limiting baffle 42 is arranged at the joint of the trapping material and the trapping box 41; the limiting baffle 42 can improve the stability of the connection of the trapping material and the trapping box 41, thereby improving the effect of the trapping material; the PLC is respectively and electrically connected with the air pump 23, the blowing motor 24, the swing motor 321 and the pressure pump 33; the PLC controller, the air pump 23, the blowing motor 24, the swing motor 321 and the pressure pump 33 are all commercially available products.

Example 11

A method for detecting and analyzing benzene series in underground water of a polluted site comprises the following steps:

s1, sampling

S1-1, determining a pollution treatment boundary of a pollution site and the height of a groundwater level, and then equidistantly setting a plurality of groundwater sampling points in an internal area of the pollution treatment boundary;

s1-2, drilling pumping wells at different depths at each underground water sampling point according to the underground water level obtained in the step S1-1, and then pumping and flushing the pumping wells; the method specifically comprises the following steps: continuously draining water for 25min at the maximum water yield of the pumping well; finally, pumping underground water in each pumping well to obtain a sample to be detected; wherein the depths of the pumping wells are arranged in an arithmetic progression, and the depths of the pumping wells are 15 m;

s2 sample pretreatment

Adding a 35% silver carbonate solution into the sample to be detected obtained in the step S1-2, fully stirring to obtain a reaction solution, and then filtering the reaction solution by using a filter membrane with the pore diameter of 0.45 mu m to obtain a pretreated sample; wherein the volume ratio of the silver carbonate solution to the sample to be detected is 1: 16; adding an intermediate solvent with the volume of 35% of that of the pretreated sample, and uniformly mixing the mixture by shaking; the intermediate solvent is formed by mixing methanol and perylene-d 12 in equal volume; introducing the pretreated sample into a quartz photolysis tube, and irradiating the quartz photolysis tube for 55min by using a vacuum ultraviolet lamp with the wavelength of 165 nm;

s3, extracting benzene series

S3-1, heating the pretreated sample obtained in the step S2 to 90 ℃, then placing the sample into a purging and trapping device, purging the heated pretreated sample by using nitrogen, and collecting the purged gas through a trapping material in the purging and trapping device to obtain a trapping material after trapping the gas; wherein the purging flow of the purging and trapping equipment is controlled to be 35mL/min, and the purging temperature is controlled to be 120 ℃;

s3-2, heating the trapping material subjected to the gas trapping obtained in the step S3-1 to 450 ℃ to obtain a resolved gas;

s4, detection analysis

Introducing the analysis gas obtained in the step S3-2 into a gas chromatography mass spectrometer for qualitative and quantitative analysis, wherein the chromatographic column is a DB-VRX quartz capillary column, and the tuning mode is DFTPP tuning; the chromatographic condition is that the carrier gas is high-purity helium gas, the flow rate is 1.2mL/min, split flow sampling is carried out at a ratio of 15:1, the temperature of a sample inlet is 230 ℃, the temperature of a column box is 40 ℃, the temperature raising program is kept for 2min at 40 ℃, and the temperature raising program is kept for 3min at 250 ℃ at the speed of 20 ℃/min; the mass spectrometry conditions are that the ion source temperature is 230 ℃, the interface temperature is 250 ℃, the solvent delay time is 0.5min, and an ion detection SCAN mode is adopted; finally, carrying out a blank standard adding experiment and a parallel experiment, wherein the relative percentage deviation of each compound in the blank standard adding experiment is less than 20%, and the recovery rate is 70-130%; the relative percentage deviation of the parallel experiment samples is less than 30%, and the matrix standard adding recovery rate of the water sample is 70-130%.

Example 12

The embodiment describes detection and analysis equipment for benzene series in underground water of a polluted site, which is suitable for the detection and analysis equipment of the benzene series in the underground water of the polluted site in the embodiment 11, and comprises sampling equipment for collecting an underground water sample, pretreatment equipment for pretreating a sample to be detected, ultrafiltration membrane filtration equipment in the prior art, purging and trapping equipment for extracting the benzene series in the pretreated sample, and a gas chromatography mass spectrometer for detecting and analyzing the benzene series in the underground water; the sweeping and trapping device comprises a device box 1, a sweeping component 2, a sample introduction component 3, a trapping component 4 and a PLC (programmable logic controller); the lower end of the equipment box 1 is provided with a base 10, the upper end is provided with an air inlet pipe 11 and a sample inlet pipe 12, and the side wall is provided with a liquid discharge pipe 13; the blowing component 2 comprises a blowing box 20, an air collecting sleeve 21, an air homogenizing disc 22 and an air pump 23, the blowing box 20 is fixedly arranged at one end of the equipment box 1 and communicated with the inside of the equipment box 1, a blowing motor 24 is arranged on the outer wall of the blowing box 20, an output shaft of the blowing motor 24 penetrates through the blowing box 20 and is provided with an impeller 240, the air collecting sleeve 21 is fixedly arranged at one side, close to the blowing box 20, of the inside of the equipment box 1, the air homogenizing disc 22 is sleeved inside the air collecting sleeve 21 and is communicated with the air inlet pipe 11, a plurality of air nozzles 220 are uniformly distributed at one side, far away from the blowing box 20, of the air homogenizing disc 22, 3 air inlet flow channels 221 are arranged inside the air homogenizing disc 22, the air inlet flow channels 221 are communicated with one another, and the air nozzles 220 correspond to the positions of the air inlet flow channels 221 and are communicated with one another; by arranging the plurality of air inlet channels 221, the uniformity of air injection of each air nozzle 220 can be improved, so that the sweeping efficiency of the benzene series in the underground water is improved; the air pump 23 is fixedly arranged on the base 10, and the output end of the air pump 23 is communicated with the air inlet pipe 11; the sample feeding assembly 3 comprises a sample feeding ring 30, movable nozzles 31, a swinging member 32 and a pressure pump 33, wherein the sample feeding ring 30 is movably clamped inside the equipment box 1, the sample feeding ring 30 is hollow and communicated with the sample feeding pipe 12, the number of the movable nozzles 31 is 8, each movable nozzle 31 is uniformly distributed on the inner side of the sample feeding ring 30 and movably hinged with the sample feeding ring 30, each movable nozzle 31 is respectively communicated with the sample feeding ring 30 through a hose, the swinging member 32 comprises a swinging sleeve 320 and a swinging motor 321, the swinging sleeve 320 is rotatably clamped inside the equipment box 1 through a connecting sleeve 322, each movable nozzle 31 is provided with a movable shaft 310, the side wall of the swinging sleeve 320 is provided with an arc chute 323 corresponding to each movable shaft 310, each movable shaft 310 is respectively clamped in the arc chute 323 corresponding to the position in a sliding manner, the lower end of the swinging sleeve 320 is provided with a gear groove 324, the swinging motor 321 is fixedly arranged inside the equipment box 1, a driving gear 3210 is arranged on an output shaft of the swing motor 321, the driving gear 3210 is meshed with the gear groove 324, and the swing motor 321 is electrically connected with the PLC controller; the swing motor 321 drives the swing sleeve 320 to swing in a reciprocating manner, so that each movable nozzle 31 swings in a reciprocating manner in the sample injection ring 30, underground water samples on the inner side of the sample injection ring 30 are distributed more uniformly, and the sweeping and trapping efficiency of the benzene series is improved; the pressure pump 33 is fixedly arranged on the base 10, and the output end of the pressure pump 33 is communicated with the sampling pipe 12; the collecting component 4 comprises a mounting sleeve 40 and a collecting box 41, the mounting sleeve 40 is fixedly arranged at the other end of the equipment box 1 and extends into the equipment box 1, the collecting box 41 is movably clamped inside the mounting sleeve 40, a plurality of exhaust holes are uniformly formed in the collecting box 41, a collecting material is movably clamped inside the collecting box 41, and the collecting material is a polyacrylate solid-phase micro-extraction needle with the thickness of 55 microns; a limiting baffle 42 is arranged at the joint of the trapping material and the trapping box 41; the limiting baffle 42 can improve the stability of the connection of the trapping material and the trapping box 41, thereby improving the effect of the trapping material; the PLC is respectively and electrically connected with the air pump 23, the blowing motor 24, the swing motor 321 and the pressure pump 33; the PLC controller, the air pump 23, the blowing motor 24, the swing motor 321 and the pressure pump 33 are all commercially available products.

Test examples

The methods of the embodiments 1, 3, 5, 7, 9 and 11 of the invention are respectively used for detecting and analyzing the benzene series in the groundwater of a certain chemical plant in south China, and the results are shown in the table 1:

table 1 influence of each example on the detection result of benzene series in groundwater;

as can be seen from the data in table 1: compared with the distinguishing scheme of the embodiment 1, the embodiment 3 has the advantages that the content of the benzene series in the underground water tends to be stable by performing well flushing treatment on the pumping well, so that the accuracy of the detection result of the benzene series in the underground water can be improved; by pumping the underground water with different depths, the interference of the content difference of the benzene series in the underground water with different depths on the detection and analysis result can be eliminated, and the accuracy of the detection and analysis result is improved;

example 5 compared with example 1, the stability and uniformity of the benzene series dispersion in the pretreated sample can be changed by adding the intermediate solvent formed by mixing methanol and perylene-d 12 into the pretreated sample, so that the accuracy and precision of the detection and analysis method are improved;

compared with the embodiment 1, the embodiment 7 can avoid the influence of external environmental factors on the detection and analysis result by carrying out a blank labeling experiment and a parallel experiment, thereby ensuring the accuracy and reliability of the detection and analysis result;

compared with the embodiment 1, the embodiment 9 has the advantages that inorganic halogen ions in the pretreated sample can be removed by performing photolysis treatment on the pretreated sample, and a good foundation is laid for sweeping and trapping benzene series in underground water; meanwhile, the sweeping and trapping equipment can trap benzene series in the underground water more comprehensively and thoroughly; the swinging motor drives the swinging sleeve to swing in a reciprocating manner, so that each movable nozzle swings in a reciprocating manner in the sample injection ring, underground water samples on the inner side of the sample injection ring are distributed more uniformly, and the sweeping and trapping efficiency of the benzene series is improved; the limit baffle is arranged, so that the connection stability of the trapping material and the trapping box can be improved, and the action effect of the trapping material is improved; the air inlet channels are arranged, so that the air injection uniformity of each air injection nozzle can be improved, and the sweeping efficiency of the benzene series in the underground water is improved;

in example 11, compared with examples 1, 3, 5, 7 and 9, the detection limit, precision and accuracy of the benzene series in the groundwater of the polluted site can be optimized by integrating and optimizing the parameter conditions.

Claims (10)

1. A method for detecting and analyzing benzene series in underground water of a polluted site is characterized by comprising the following steps:

s1, sampling

S1-1, determining a pollution treatment boundary of a pollution site and the height of a groundwater level, and then equidistantly setting a plurality of groundwater sampling points in an internal area of the pollution treatment boundary;

s1-2, drilling pumping wells at different depths at each underground water sampling point according to the underground water level height obtained in the step S1-1, and then pumping underground water in each pumping well to obtain a sample to be detected;

s2 sample pretreatment

Adding a silver carbonate solution with the mass concentration of 15-35% into the sample to be detected obtained in the step S1-2, fully stirring to obtain a reaction solution, and then filtering the reaction solution by using a filter membrane with the pore diameter of 0.30-0.45 mu m to obtain a pretreated sample; the volume ratio of the silver carbonate solution to the sample to be detected is 1: 9-16;

s3, extracting benzene series

S3-1, heating the pretreated sample obtained in the step S2 to 40-90 ℃, then placing the sample into a purging and trapping device, purging the heated pretreated sample by using nitrogen, and collecting the purged gas through a trapping material in the purging and trapping device to obtain a trapping material after trapping the gas; wherein the purging flow of the purging and trapping equipment is controlled to be 15-35 mL/min, and the purging temperature is controlled to be 80-120 ℃;

s3-2, heating the trapping material subjected to gas trapping obtained in the step S3-1 to 260-450 ℃ to obtain a resolved gas;

s4, detection analysis

Introducing the analysis gas obtained in the step S3-2 into a gas chromatography mass spectrometer for qualitative and quantitative analysis, wherein the chromatographic column is a DB-VRX quartz capillary column, and the tuning mode is DFTPP tuning; the chromatographic condition is that the carrier gas is high-purity helium gas, the flow rate is 1.2mL/min, split flow sampling is carried out at a ratio of 15:1, the temperature of a sample inlet is 230 ℃, the temperature of a column box is 40 ℃, the temperature raising program is kept for 2min at 40 ℃, and the temperature raising program is kept for 3min at 250 ℃ at the speed of 20 ℃/min; the mass spectrometry conditions are that the ion source temperature is 230 ℃, the interface temperature is 250 ℃, the solvent delay time is 0.5min, and the ion detection SCAN mode is adopted.

2. The method for detecting and analyzing the benzene series in the underground water of the polluted site according to claim 1, wherein in step S1-2, before the sample to be detected is extracted, the pumping well is pumped and flushed; the method specifically comprises the following steps: and continuously draining for 10-25 min by using the maximum water yield of the pumping well.

3. The method for detecting and analyzing the benzene series in the underground water of the polluted site according to claim 1, wherein after the step S2 is completed, an intermediate solvent with the volume of 20-35% of that of the pretreated sample is added into the pretreated sample, and the mixture is vibrated and uniformly mixed; the intermediate solvent is formed by mixing methanol and perylene-d 12 in equal volume.

4. The method for detecting and analyzing the benzene series in the underground water of the polluted site according to claim 1, wherein in the step S1-2, the depths of the pumping wells are arranged in an arithmetic progression and are 8-15 m.

5. The method for detecting and analyzing the benzene series in the underground water of the polluted site according to claim 1, wherein after the step S4 is completed, a blank standard addition experiment and a parallel experiment are performed, the relative percentage deviation of each compound in the blank standard addition experiment is less than 20%, and the recovery rate is 70-130%; the relative percentage deviation of the parallel experiment samples is less than 30%, and the matrix standard adding recovery rate of the water sample is 70-130%.

6. The method for detecting and analyzing the benzene series in the underground water of the polluted site according to claim 1, wherein after the step S2 is completed, the pretreated sample is introduced into a quartz photolysis tube, and the quartz photolysis tube is irradiated for 25-55 min by using a vacuum ultraviolet lamp with a wavelength of 85-165 nm.

7. The detection and analysis equipment for the benzene series in the underground water of the polluted site for the method of any one of claims 1 to 6 is characterized by comprising sampling equipment for collecting underground water samples, pretreatment equipment for pretreating the samples to be detected, purging and trapping equipment for extracting the benzene series in the pretreated samples and a gas chromatography mass spectrometer for detecting and analyzing the benzene series in the underground water; the purging and trapping device comprises a device box (1), a purging component (2), a sample injection component (3), a trapping component (4) and a PLC (programmable logic controller); a base (10) is arranged at the lower end of the equipment box (1), an air inlet pipe (11) and a sample inlet pipe (12) are arranged at the upper end of the equipment box, and a liquid discharge pipe (13) is arranged on the side wall of the equipment box; the purging component (2) comprises a purging box (20), a gas collecting sleeve (21), a gas homogenizing disc (22) and an air pump (23), the purging box (20) is fixedly arranged at one end of the equipment box (1), and is communicated with the inside of the equipment box (1), the outer wall of the purging box (20) is provided with a purging motor (24), an output shaft of the purging motor (24) penetrates through the purging box (20) and is provided with an impeller (240), the gas collecting sleeve (21) is fixedly arranged at one side of the inside of the equipment box (1) close to the purging box (20), the gas homogenizing disc (22) is sleeved inside the gas collecting sleeve (21), and is communicated with the air inlet pipe (11), a plurality of air nozzles (220) are uniformly distributed on one side of the air-homogenizing disc (22) far away from the purging box (20), the air pump (23) is fixedly arranged on the base (10), and the output end of the air pump (23) is communicated with the air inlet pipe (11); the sample injection assembly (3) comprises a sample injection ring (30), movable nozzles (31), a swinging member (32) and a pressure pump (33), wherein the sample injection ring (30) is movably connected inside the equipment box (1), the sample injection ring (30) is hollow inside and is communicated with the sample injection pipe (12), the movable nozzles (31) are provided with a plurality of movable nozzles (31), the movable nozzles (31) are uniformly distributed inside the sample injection ring (30) and are movably hinged with the sample injection ring (30), the movable nozzles (31) are respectively connected and communicated with the sample injection ring (30) through hoses, the swinging member (32) is movably connected and connected inside the equipment box (1) and is used for adjusting the reciprocating swinging of the movable nozzles (31), the pressure pump (33) is fixedly arranged on the base (10), and the output end of the pressure pump (33) is communicated with the sample injection pipe (12); the catching assembly (4) comprises an installation sleeve (40) and a catching box (41), the installation sleeve (40) is fixedly arranged at the other end of the equipment box (1) and extends into the equipment box (1), the catching box (41) is movably clamped inside the installation sleeve (40), a plurality of exhaust holes are uniformly formed in the catching box (41), and catching materials are movably clamped inside the catching box (41); the PLC is respectively and electrically connected with the air pump (23), the blowing motor (24) and the pressure pump (33).

8. The device for detecting and analyzing the benzene series in the underground water of the polluted site according to claim 7, wherein the trapping material is a polyacrylate solid-phase micro-extraction needle with the thickness of 55-75 μm.

9. The detection and analysis equipment for the benzene series in the groundwater of the dyeing field according to claim 7, wherein the swing member (32) comprises a swing sleeve (320) and a swing motor (321), the swing sleeve (320) is rotatably clamped inside the equipment box (1) through a connecting sleeve (322), each movable nozzle (31) is provided with a movable shaft (310), the side wall of the swing sleeve (320) is provided with an arc chute (323) corresponding to the position of each movable shaft (310), each movable shaft (310) is respectively clamped in the arc chute (323) corresponding to the position in a sliding manner, the lower end of the swing sleeve (320) is provided with a gear groove (324), the swing motor (321) is fixedly arranged inside the equipment box (1), the output shaft of the swing motor (321) is provided with a driving gear (3210), and the driving gear (3210) is meshed with the gear groove (324), the swing motor (321) is electrically connected with the PLC controller.

10. The method for detecting and analyzing the benzene series in the underground water of the polluted site according to claim 1, wherein the trapping material is a polyacrylate solid-phase micro-extraction needle with the thickness of 55-75 μm.

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