CN109900680B - Detection method and detection device for rare earth elements in pore water - Google Patents
Detection method and detection device for rare earth elements in pore water Download PDFInfo
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Abstract
The invention discloses a detection method and a detection device for rare earth elements in pore water, and relates to the technical field of rare earth element detection. The detection method of the rare earth elements in the pore water comprises the steps of utilizing an adsorption pipeline formed by a sample tank and an adsorption tube to make liquid to be adsorbed on resin in the adsorption tube, then utilizing an elution pipeline formed by an elution liquid tank, the adsorption tube and an elution sample tank to introduce pressure gas and eluent into the adsorption tube, and eluting substances adsorbed on the resin to enter the elution sample tank. The detection method of the rare earth elements in the pore water utilizes a sample tank, an adsorption tube and a pump set which are sequentially connected to form an adsorption pipeline, and utilizes an elution liquid tank, the adsorption tube and an elution sample tank which are sequentially connected to form an elution pipeline. The enrichment process of the rare earth elements is carried out by utilizing a closed pipeline, so that the pollution of the external environment is avoided; the pressure gas and the eluent are used for elution in parallel, the elution speed is high, the effect is good, and the accuracy of the subsequent detection process is improved.
Description
Technical Field
The invention relates to the technical field of rare earth element detection, in particular to a detection method and a detection device for rare earth elements in pore water.
Background
Rare Earth Elements (REEs) are extremely important tracers for geochemical processes in the ocean, but because the concentration of the rare earth elements is more than pmol/kg, the analysis and the test are difficult. Particularly, the test of the rare earth elements in the sediment pore water is performed because only about 10mL of rare earth elements are obtained from the sediment through centrifugal separation each time, the salinity is close to that in seawater, and the content of organic matters is high, so that the difficulty of analysis and test is increased. In order to make rare earth elements more widely used in marine research, accurate measurement of low concentration of rare earth elements in sediment pore water is necessary.
Inductively coupled plasma mass spectrometry (ICP-MS) can be used for multi-element analysis, but because the content of Y (yttrium) + REEs in pore water is extremely low and the content of salt is very high, the direct measurement can cause the problems of instrument atomizer blockage, high background, matrix interference and the like, thereby causing the reduction of sensitivity and accuracy. Therefore, pretreatment using enrichment separation combined with ICP-MS testing is a current trend in analysis.
However, the conventional analysis methods have the following problems: (1) the interference of multiple elements cannot be removed in one step in the pretreatment process, and the accuracy of the detection result is poor; (2) the REEs enrichment process is complex, a large amount of reagents are consumed, the consumed time is long, and the recovery rate is low; (3) the sample quantity is more, and the online test has more loss to the instrument; (4) the REEs enrichment process does not achieve effective enrichment of the REEs, and pollution is easy to generate by adopting a non-closed system.
Disclosure of Invention
The invention aims to provide a pretreatment method for testing rare earth elements, which aims to ensure that the enrichment process is in a fully closed state, improve the elution rate and avoid the pollution of the external environment.
The invention also aims to provide a pretreatment device for testing the rare earth elements, which is convenient to operate, has a closed enrichment process and a high elution rate.
The third objective of the present invention is to provide a method for detecting rare earth elements, which has the advantages of fast detection rate, high recovery rate of elements, and no environmental pollution.
The technical problem to be solved by the invention is realized by adopting the following technical scheme.
The invention provides a pretreatment method for testing rare earth elements, which adopts a pretreatment device to carry out treatment, wherein the pretreatment device comprises a sample tank, an adsorption tube, an elution sample tank and an elution liquid tank, and the sample tank is used for containing cleaning liquid or liquid to be adsorbed;
the sample tank is communicated with the adsorption pipe through a pipeline to form a closed adsorption pipeline; the elution liquid tank, the adsorption tube and the elution sample tank are communicated in sequence to form a closed elution pipeline;
the pretreatment method comprises the following steps:
filling resin for enriching rare earth elements into an adsorption tube, preparing a sample containing the rare earth elements into a liquid to be adsorbed, introducing the liquid to be adsorbed into the adsorption tube, enriching and then discharging;
and introducing the elution pressure gas into an elution liquid tank, introducing the elution pressure gas and the elution liquid into an adsorption tube to elute the resin, and then introducing the eluted solution into an elution sample tank.
The invention also provides a pretreatment device for testing the rare earth elements, which comprises a pump set, a sample tank for containing cleaning liquid or liquid to be adsorbed, an adsorption tube for containing resin, an elution sample tank for containing an elution sample and an elution liquid tank for containing solution for elution, wherein the elution liquid tank is connected with a pressure gas conveying pipeline, and the gas outlet end of the pressure gas conveying pipeline extends into the elution liquid tank;
the sample tank, the adsorption pipe and the pump set are sequentially connected to form an adsorption pipeline;
the elution liquid tank, the adsorption tube and the elution sample tank are sequentially connected to form an elution pipeline.
The invention also provides a method for detecting the rare earth element, which comprises an instrument analysis process and the pretreatment method;
wherein, the instrumental analysis process is to analyze elements in the elution sample obtained in the pretreatment method;
preferably, the instrumental analysis process is measured by an ICP-MS instrument;
further preferably, the atomizer of the ICP-MS instrument adopts an Apex atomizer.
The embodiment of the invention provides a pretreatment method for rare earth element testing, which has the beneficial effects that: and adsorbing the liquid to be adsorbed on the resin in the adsorption tube by using an adsorption pipeline formed by the sample tank and the adsorption tube, introducing pressure gas and eluent into the adsorption tube by using an elution pipeline formed by the eluent tank, the adsorption tube and the elution sample tank, and eluting the substances adsorbed on the resin into the elution sample tank. The enrichment process of the rare earth elements is carried out by utilizing a closed pipeline, so that the pollution of the external environment is avoided; the pressure gas and the eluent are used for elution in parallel, the elution speed is high, the effect is good, and the accuracy of the subsequent detection process is improved.
The invention also provides a pretreatment device for testing the rare earth elements, which utilizes the sequential connection of the sample tank, the adsorption tube and the pump set to form an adsorption pipeline, and the liquid to be adsorbed in the sample tank passes through the adsorption tube under the drive of the pump set, so that various rare earth elements are adsorbed on the resin in the adsorption tube; an elution pipeline is formed by utilizing an elution liquid tank, an adsorption pipe and an elution sample tank which are sequentially connected, and pressure gas and elution liquid output by a pressure gas conveying pipeline parallelly pass through the adsorption pipe and are collected in the elution sample tank. The rare earth element adsorption and elution processes are operated by independent and closed pipelines, so that the pollution of the external environment is avoided, and the detection rate is improved.
The invention also provides a method for detecting the rare earth element, which comprises an instrument analysis process and the pretreatment method; wherein the instrumental analysis process is to analyze elements in the elution sample obtained in the pretreatment method. The whole detection method has short detection period and high element recovery rate, and avoids the pollution of the external environment.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic structural diagram of a pretreatment device for rare earth element testing according to an embodiment of the present invention;
FIG. 2 shows the results of the measurement of the recovery of REEs by the treatment method according to the embodiment of the present invention.
Icon: 100-a pretreatment device; 101-an adsorption line; 102-an elution line; 103-buffer conditioning line; 110-sample tank; 120-a sorbent tube; 130-elution sample tank; 140-an eluent tank; 150-pump group; 160-pressure gas conveying pipeline; 170-buffer tank; 181-a first multi-way valve; 182-a second multi-way valve; 183-third multi-way valve; 184-nine way valve; 190-air filtration membrane.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The following describes a method and an apparatus for detecting rare earth elements in pore water according to embodiments of the present invention.
Referring to fig. 1, a pretreatment apparatus 100 is used for performing a pretreatment method for testing a rare earth element according to an embodiment of the present invention, the pretreatment apparatus 100 includes a sample tank 110, an adsorption tube 120, an elution sample tank 130, and an elution liquid tank 140, the sample tank 110 is used for containing a cleaning liquid or a liquid to be adsorbed; the sample tank 110 is communicated with the adsorption pipe 120 through a pipeline to form a closed adsorption pipeline 101; the elution liquid tank 140, the adsorption tube 120 and the elution sample tank 130 are sequentially communicated to form a closed elution line 102. The closed adsorption pipeline 101 and the elution pipeline 102 are used for enrichment and elution of elements respectively, the operation is convenient, and the pollution of the external environment is avoided.
Specifically, the pretreatment method comprises the following steps:
s1, resin cleaning and filling
The resin for adsorbing rare earth elements may be a commercially available resin commonly used for adsorbing rare earth elements, such as polyurethane, epoxy resin, or the like. Preferably, the resin for enriching rare earth elements contains ethylene diamine tetraacetic acid ammonium groups and iminodiacetic acid groups, and can be selected from NOBIAS chelate-PA1 type resin. The inventor finds that the resin of the type can quickly and efficiently adsorb rare earth elements, is easy to elute by nitric acid and has high reusability. This is probably because this type of resin forms many coordination bonds with metal ions, and the adsorption performance is very ideal, and the specific results are as follows:
preferably, before the resin is filled in the adsorption tube 120, washing is performed a plurality of times with methanol and water, respectively; if the purchased resin itself has been washed or has not adsorbed other metal ions, then no washing may be performed. Specifically, the multiple rinsing may be performed by rinsing with methanol four times and then rinsing with deionized water four times.
Further, the filling of the resin in the adsorption tube 120 depends on gravity to fill the resin, and the deionized water is driven to flow through the resin when the filling is nearly full. The specific operation is as follows: and (3) sucking the deionized water mixed solution soaked with the resin by using a liquid transfer gun, slowly filling the resin tube (with the length of 2cm) by virtue of gravity, and allowing the deionized water to flow through the resin under the driving of a peristaltic pump when the resin tube is nearly full of the resin tube. As the volume of the adsorption tube 120 is only 27uL (Global FIA) generally, the resin can be uniformly distributed in the resin tube while avoiding air bubbles generated during resin filling, so that the solution can pass through the resin tube at a constant speed, and the enrichment effect is optimized.
S2, assembling equipment
Fig. 1 shows two sets of pretreatment apparatuses, and one set may be assembled in practical application, or two or more sets may be assembled if the treatment capacity is large.
Preferably, the resin in the device is cleaned after the device is assembled and before adsorption is performed, so that metal ions on the resin are further removed to prevent interference on the detection result. Specifically, the resin is washed by sequentially using HCl solution with concentration of 5.5-6.5N, ocean seawater with pH of 1.8-2.2, and HNO with concentration of 1.8-2.2N3Solution, HNO with concentration of 1.8-2.2N3The solution, deionized water and ocean water with pH 1.8-2.2. Wherein, the time of the seawater cleaning process is about 10 to 14 hours, and the rest cleaning steps are about 2 hours. This step of washing may be carried out by adding a washing solution to the sampleIn the tank 110, the adsorption line 101 is used for cleaning, and metal ions on the resin are washed away through multiple times of cleaning, and on the other hand, the resin is continuously expanded and contracted, so that the adsorption effect on the rare earth elements is improved.
The pH of ocean water having a pH of 1.8 to 2.2 is adjusted to 1.8 to 2.2.
The following describes the pretreatment apparatus 100 according to an embodiment of the present invention.
The embodiment of the invention also provides a pretreatment device 100 for rare earth element testing, which comprises a pump unit 150, a sample tank 110 for containing cleaning liquid or liquid to be adsorbed, an adsorption tube 120 for containing resin, an elution sample tank 130 for containing an elution sample, and an elution liquid tank 140 for containing solution for elution, wherein the elution liquid tank 140 is connected with a pressure gas conveying pipeline 160, and the gas outlet end of the pressure gas conveying pipeline 160 extends into the elution liquid tank 140. The sample tank 110, the adsorption pipe 120 and the pump unit 150 are connected in sequence to form an adsorption pipeline 101; the elution liquid tank 140, the adsorption tube 120 and the elution sample tank 130 are connected in sequence to form an elution line 102.
In some embodiments, a first multi-way valve 181 and a second multi-way valve 182 are installed on a communication pipeline between the sample tank 110 and the adsorption tube 120, and the pretreatment apparatus further includes a buffer tank 170; the sample tank 110 and the buffer liquid tank 170 are communicated with the first multi-way valve 181, so that the sample tank 110 is sequentially connected with the adsorption tube 120 through the first multi-way valve 181 and the second multi-way valve 182, and the buffer liquid tank 170 is sequentially connected with the adsorption tube 120 through the first multi-way valve 181 and the second multi-way valve 182. The buffer tank 170 is used to store buffer for adjusting the pH of the resin.
In some embodiments, a third multi-way valve 183 is installed on the communication pipeline between the eluent tank 140 and the adsorption tube 120; the eluent tank 140 is connected with the elution sample tank 130 through a third multi-way valve 183, an adsorption tube 120 and a second multi-way valve 182 in sequence to form an elution line 102; the sample tank 110 is connected with the pump group 150 through a first multi-way valve 181, a second multi-way valve 182, an adsorption tube 120 and a third multi-way valve 183 in sequence to form an adsorption pipeline 101; the buffer liquid tank 170 is connected to the pump group 150 through a first multi-way valve 181, a second multi-way valve 182, an adsorption tube 120, and a third multi-way valve 183 in order to form a buffer adjustment line 103. The adsorption line 101 and the buffer adjustment line 103 are used by switching the connection of the first multi-way valve 181 to the sample tank 110 and the buffer tank 170.
Preferably, the first multi-way valve 181, the second multi-way valve 182 and the third multi-way valve 183 are four-way valves, and the switching of pipelines can be satisfied by commercially available four-way valves, so that the operation is convenient.
Specifically, the pump unit 150 may be a peristaltic pump, and a nine-way valve 184 may be disposed between the eluent tank 140 and the third multi-way valve 183 to switch between different sets of elution lines 102 in order to achieve simultaneous operation of multiple sets of pretreatment apparatuses 100. During the operation, the pump speed of the peristaltic pump is preferably adjusted to about 0.5 mL/min.
It should be added that an air filtering membrane 190 may be added at the end of the pressure gas conveying pipeline 160 to filter the pressure gas passing through the eluent tank 140.
It should be noted that the shape of the sample tank 110, the adsorption tube 120, the eluent liquid tank 140, the elution sample tank 130, and other containers provided in the embodiments of the present invention may be various shapes, and is not limited to the shape shown in the drawings.
S3, preparation of liquid to be adsorbed and cleaning of device
The pretreatment method provided by the embodiment of the invention can be suitable for a large amount of test samples, and is particularly suitable for pore water samples with small sample amount.
The preparation of the liquid to be adsorbed is mainly pH adjustment, the pH of the liquid to be adsorbed is 5.5-5.8, rare earth elements can be effectively enriched, and the detection accuracy is high. For pore water, preferably, hydrochloric acid is adopted for acidification and then deionized water is adopted for dilution in the preparation process of the solution to be adsorbed, and then NH is utilized4The pH was adjusted with AC buffer solution. The following method can be adopted in actual operation: a 2mL sample of pore water HCI was acidified to pH 2, diluted to 10mL with 8mL ultrapure water, and then 3.7mol/L NH was used4Ac buffer solution adjusts the pH of the sample to be in the range of 5.5-5.8.
Before enriching the liquid to be adsorbed in the adsorption tube 120, the nitric acid cleaning liquid in the sample tank 110 is adopted to clean the adsorption tubeThe wire 101 is cleaned to remove interfering ions; then using NH4The AC buffer solution purges adsorption line 101 to adjust the resin pH; preferably, NH4The concentration of the AC buffer solution is 0.04-0.06mol/L (pH is 5.5-5.8 is suitable). By switching the connection position of the first multi-way valve 181, the adsorption pipeline 101 and the buffer solution adjusting pipeline 103 are respectively operated, and the operation is convenient.
S4 enrichment of rare earth elements
And (2) introducing the liquid to be adsorbed into the adsorption pipe 120 for enrichment and then discharging, namely adjusting the first multi-way valve 181 to the position of the sample tank 110, and discharging the pore water sample (with the pH value of 5.5-5.8) with the adjusted pH value through the first multi-way valve 181, the second multi-way valve 182, the adsorption pipe 120, the third multi-way valve 183 and the pipeline D1# -1 in sequence through a peristaltic pump, wherein REEs in the sample are enriched on the resin.
Before elution is performed after the to-be-adsorbed solution is enriched in the adsorption tube 120, a washing buffer solution is introduced into the adsorption tube 120 to remove residual metal ions. Preferably, the wash buffer is NH4AC buffer solution, and NH4The concentration of the AC buffer solution is 0.04-0.06 mol/L. The method comprises the following specific operations: the first multi-way valve 181 is adjusted to the buffer tank 170 position, and the third multi-way valve 183 is adjusted to D1# -1, NH4The AC buffer solution is discharged through the first multi-way valve 181, the second multi-way valve 182, the adsorption pipe 120, the third multi-way valve 183 and the pipeline D1# -1 by the peristaltic pump, and the residual Na on the resin is removed+、K+、Ca2+、Mg2+And washing out the metal ions.
S5 elution of rare earth elements
The elution pressure gas is introduced into the elution liquid tank 140, and the elution pressure gas and the elution liquid are introduced into the adsorption tube 120 to elute the resin, and then the eluted solution is introduced into the elution sample tank 130. The elution pressure gas and the eluent sequentially pass through the third multi-way valve 183, the adsorption tube 120 and the second multi-way valve 182 to enter the elution sample tank 130.
Specifically, the elution pressure gas may be nitrogen gas at a low cost, provided that no interfering reaction is introduced as a selective gas. The elution sample tank 130 may be a clean 15mL centrifuge tube (pre-weighed) that will be usedEnriching Y + REEs on a resin column with 1N HNO3The solution (containing 10ppb In internal standard) was eluted and weighed.
Preferably, the pressure of the elution pressure gas introduced into the elution liquid tank 140 is 4-6psi, the elution process can be accelerated in this pressure range, too low pressure is not favorable for increasing the elution rate, and too high pressure increases the detection cost.
The embodiment of the invention also provides a method for detecting the rare earth element, which comprises an instrument analysis process and the pretreatment method; wherein, the instrumental analysis process is to analyze the elements in the elution sample obtained in the pretreatment method. The instrument used in the instrument analysis process is preferably ICP-MS (plasma mass spectrometry), and the ICP-MS is adopted to detect the rare earth elements with higher accuracy.
The inventor finds that the atomizer of the ICP-MS instrument has higher sensitivity (the sensitivity is improved by 10-20 times compared with the conventional atomizer, and the oxide yield CeO +/Ce + is optimally reduced to 0.05%), which is probably because the Apex atomizer is a Teflon solvent removal component and is compared with the conventional ICP-MS common atomizer in a direct sample injection mode.
In some embodiments, the atomization chamber can adopt a heating cyclone atomization chamber to improve the introduction efficiency of the sample, the temperature is controlled to be 40-180 ℃, the gas is controlled by 2 MFC gas mass flowmeters, the flow rate of the purging gas can be accurately controlled, and the sample introduction amount of the test sample can be reduced to 300 uL.
When ICP-MS is used for measuring Y + REEs, polyatomic ions LREEO formed by light rare earth elements, hydrogen and oxygen+LREEOH+Will interfere with the multi-atomic ion BaO formed by the medium and heavy rare earth elements with equal mass number and Ba+Or BaOH+Interference with REEs, especially Eu elemental measurements, is formed. Measurement selection of CCT mode can significantly reduce interference (Ba + +/Ba + +) of oxide and double charges on REEs test<2％，CeO/Ce<4％)。
The features and properties of the present invention are described in further detail below with reference to examples.
Example 1
The embodiment provides a pretreatment method for rare earth element testing, which comprises the following steps:
(1) resin cleaning and filling
The NOBIAS latex-PA 1 type resin was placed in a 50mL centrifuge tube, washed 4 times with 10mL methanol and 10mL deionized water, respectively, and after washing, the resin was soaked in deionized water.
And (3) sucking the deionized water mixed solution soaked with the resin by using a liquid transfer gun, slowly filling the resin tube (with the length of 2cm) by virtue of gravity, and allowing the deionized water to flow through the resin under the driving of a peristaltic pump when the resin tube is nearly full of the resin tube.
(2) Equipment assembly
The enrichment and elution were carried out using a set of pretreatment apparatuses as shown in FIG. 1, and the treatment facilities were connected in the positional relationship shown in FIG. 1.
And cleaning the resin in the equipment after the equipment is assembled and before adsorption. The resin cleaning process is that the following 8 times of cleaning are carried out in sequence, and comprises (a)200mL of 6N HCl solution; (b)200mL of ocean water having a pH of 2; (c)200mL of 6N HCl solution; (d) seawater at pH 2; (e)100mL of 2N HNO3A solution; (f) HNO at 2N concentration3A solution; (g)500mL of deionized water; (h) seawater of pH 2. Wherein the time of the seawater cleaning process is about 12 hours, and the cleaning time of the rest cleaning steps is about 2 hours.
(3) Preparation of liquid to be adsorbed and cleaning of device
A 2mL sample of pore water HCI was acidified to pH 2, diluted to 10mL with 8mL ultrapure water, and then 3.7mol/L NH was used4Ac buffer solution adjusts the pH of the sample to be in the range of 5.5-5.8.
A nitric acid cleaning solution with the concentration of 1N is filled into a sample tank 110, an adsorption pipeline 101 is cleaned, and the nitric acid cleaning solution passes through a first multi-way valve 181, a second multi-way valve 182, an adsorption pipe 120, a third multi-way valve 183 and a pipeline D1# -1 in sequence and is completely discharged through a peristaltic pump. Then using NH4The adsorption line 101 is cleaned with an AC buffer solution, NH4The concentration of the AC buffer solution was 0.05 mol/L. The first multi-way valve 181 is switched to the buffer liquid tank 170, and the buffer liquid tank 170, the first multi-way valve 181, the second multi-way valve 182, the adsorption pipe 120, the third multi-way valve 183 and the pipe are sequentially arrangedAnd a path D1# -1 which is completely discharged through a peristaltic pump.
(4) Enrichment of rare earth elements
The liquid to be adsorbed is placed in the sample tank 110, and is discharged through the first multi-way valve 181, the second multi-way valve 182, the adsorption tube 120, the third multi-way valve 183, the pipeline D1# -1 and the peristaltic pump, and REEs in the sample are enriched on resin.
NH with the concentration of 0.05mol/L4The AC buffer solution is placed in the buffer tank 170, the first multi-way valve 181 is adjusted to the position of the buffer tank 170, and the third multi-way valve 183 is adjusted to D1# -1, NH4The AC buffer solution is discharged through the peristaltic pump from a pipeline D1# -1 through the first multi-way valve 181, the second multi-way valve 182, the adsorption pipe 120 and the third multi-way valve 183 in sequence.
(5) Elution of rare earth elements
Weighing the weight of the elution sample tank 130, introducing nitrogen elution pressure gas into the elution sample tank 140, wherein the pressure in the pressure gas conveying pipeline 160 is about 5psi, and the elution pressure gas and the elution solution sequentially pass through the third multi-way valve 183, the adsorption pipe 120 and the second multi-way valve 182 and enter the elution sample tank 130. The final elution sample tank 130 is then weighed.
The embodiment also provides a method for detecting rare earth elements, wherein the elution sample obtained by elution is subjected to instrument analysis, the test instrument is an ICP-MS instrument, an Apex atomizer is adopted, and a CCT mode is selected. Specific operating parameters are shown in table 1.
TABLE 1 Instrument operating parameters
Example 2
The embodiment provides a pretreatment method for rare earth element testing, which comprises the following steps:
(1) resin cleaning and filling
The NOBIAS latex-PA 1 resin was placed in a 50mL centrifuge tube, washed 4 times with 10mL methanol and 10mL deionized water, respectively, and the resin was soaked in deionized water after washing.
And (3) sucking the deionized water mixed solution soaked with the resin by using a liquid transfer gun, slowly filling the resin tube (with the length of 2cm) by virtue of gravity, and allowing the deionized water to flow through the resin under the driving of a peristaltic pump when the resin tube is nearly full of the resin tube.
(2) Equipment assembly
The enrichment and elution were carried out using a set of pretreatment apparatuses as shown in FIG. 1, and the treatment facilities were connected in the positional relationship shown in FIG. 1.
And cleaning the resin in the equipment after the equipment is assembled and before adsorption. The resin cleaning process is that the following 8 times of cleaning are carried out in sequence, and comprises (a)200mL of HCl solution with the concentration of 5.5N; (b)200mL of ocean water having a pH of 1.8; (c)200mL of a 5.5N HCl solution; (d) seawater at pH 1.8; (e)100mL of 1.8N HNO3A solution; (f) HNO concentration of 1.8N3A solution; (g)500mL of deionized water; (h) seawater pH 1.8. Wherein the time of the seawater cleaning process is about 12 hours, and the cleaning time of the rest cleaning steps is about 2 hours.
(3) Preparation of liquid to be adsorbed and cleaning of device
A 2mL sample of pore water HCI was acidified to pH 2, diluted to 10mL with 8mL ultrapure water, and then 3.7mol/L NH was used4Ac buffer solution adjusts the pH of the sample to be in the range of 5.5-5.8.
A nitric acid cleaning solution with the concentration of 1N is filled into the sample tank 110, the adsorption pipeline 101 is cleaned, and the nitric acid cleaning solution is discharged through a peristaltic pump after passing through the first multi-way valve 181, the second multi-way valve 182, the adsorption pipe 120, the third multi-way valve 183 and a pipeline D1# -1 in sequence. Then using NH4The adsorption line 101 is cleaned with an AC buffer solution, NH4The concentration of the AC buffer solution was 0.04 mol/L. And the first multi-way valve 181 is switched to the buffer liquid tank 170, and the buffer liquid is discharged through the peristaltic pump after passing through the buffer liquid tank 170, the first multi-way valve 181, the second multi-way valve 182, the adsorption pipe 120, the third multi-way valve 183 and the pipeline D1# -1 in sequence.
(4) Enrichment of rare earth elements
The liquid to be adsorbed is placed in the sample tank 110, and is discharged through the first multi-way valve 181, the second multi-way valve 182, the adsorption tube 120, the third multi-way valve 183, the pipeline D1# -1 and the peristaltic pump, and REEs in the sample are enriched on resin.
NH with the concentration of 0.04mol/L4The AC buffer solution is placed in the buffer tank 170, the first multi-way valve 181 is adjusted to the position of the buffer tank 170, and the third multi-way valve 183 is adjusted to D1# -1, NH4The AC buffer solution is discharged from a pipeline D1# -1 through a peristaltic pump through a first multi-way valve 181, a second multi-way valve 182, the adsorption pipe 120 and a third multi-way valve 183 in sequence.
(5) Elution of rare earth elements
Weighing the weight of the elution sample tank 130, introducing nitrogen elution pressure gas into the elution sample tank 140, wherein the pressure in the pressure gas conveying pipeline 160 is about 4psi, and the elution pressure gas and the elution solution sequentially pass through the third multi-way valve 183, the adsorption tube 120 and the second multi-way valve 182 to enter the elution sample tank 130. The final elution sample tank 130 is then weighed.
This example also provides a method for detecting rare earth elements, which is to perform instrumental analysis on an eluted sample obtained by elution, specifically referring to example 1.
Example 3
The embodiment provides a pretreatment method for rare earth element testing, which comprises the following steps:
(1) resin cleaning and filling
The NOBIAS latex-PA 1 resin was placed in a 50mL centrifuge tube, washed 4 times with 10mL methanol and 10mL deionized water, respectively, and the resin was soaked in deionized water after washing.
And (3) sucking the deionized water mixed solution soaked with the resin by using a liquid transfer gun, slowly filling the resin tube (with the length of 2cm) by virtue of gravity, and allowing the deionized water to flow through the resin under the drive of a peristaltic pump when the resin tube is nearly full of the resin tube.
(2) Equipment assembly
The enrichment and elution were carried out using a set of pretreatment apparatuses as shown in FIG. 1, and the treatment facilities were connected in the positional relationship shown in FIG. 1.
And cleaning the resin in the equipment after the equipment is assembled and before adsorption. The resin cleaning process is that the following 8 times of cleaning are carried out in sequence, and comprises (a)200mL of 6.5N HCl solution; (b)200mL of ocean water having a pH of 2.2; (c)200mL of 6.5N HCl solution; (d) seawater at pH 2.2; (e)100mL of 2.2N HNO3A solution; (f) HNO with concentration of 2.2N3A solution; (g)500mL of deionized water; (h) seawater pH 2.2. Wherein the time of the seawater cleaning process is about 12 hours, and the cleaning time of the rest cleaning steps is about 2 hours.
(3) Preparation of liquid to be adsorbed and cleaning of device
A 2mL sample of pore water HCI was acidified to pH 2, diluted to 10mL with 8mL ultrapure water, and then 3.7mol/L NH was used4Ac buffer solution adjusts the pH of the sample to be in the range of 5.5-5.8.
A nitric acid cleaning solution with the concentration of 1N is filled into a sample tank 110, an adsorption pipeline 101 is cleaned, and the nitric acid cleaning solution passes through a first multi-way valve 181, a second multi-way valve 182, an adsorption pipe 120, a third multi-way valve 183 and a pipeline D1# -1 in sequence and is completely discharged through a peristaltic pump. Then using NH4The adsorption line 101 is purged with an AC buffer solution, NH4The concentration of the AC buffer solution was 0.06 mol/L. And the first multi-way valve 181 is switched to the buffer liquid tank 170, and the buffer liquid is discharged through the peristaltic pump after passing through the buffer liquid tank 170, the first multi-way valve 181, the second multi-way valve 182, the adsorption pipe 120, the third multi-way valve 183 and the pipeline D1# -1 in sequence.
(4) Enrichment of rare earth elements
The liquid to be adsorbed is placed in the sample tank 110, and is discharged through the first multi-way valve 181, the second multi-way valve 182, the adsorption tube 120, the third multi-way valve 183, the pipeline D1# -1 and the peristaltic pump, and REEs in the sample are enriched on resin.
NH with the concentration of 0.06mol/L4The AC buffer solution is placed in the buffer tank 170, the first multi-way valve 181 is adjusted to the position of the buffer tank 170, and the third multi-way valve 183 is adjusted to D1# -1, NH4The AC buffer solution passes through the first multi-way valve 181, the second multi-way valve 182, the adsorption pipe 120 and the third multi-way valve in sequenceThe valve 183 discharges all from line D1# -1 via the peristaltic pump.
(5) Elution of rare earth elements
Weighing the weight of the elution sample tank 130, introducing nitrogen elution pressure gas into the elution sample tank 140, wherein the pressure in the pressure gas conveying pipeline 160 is about 6psi, and the elution pressure gas and the elution solution sequentially pass through the third multi-way valve 183, the adsorption pipe 120 and the second multi-way valve 182 and enter the elution sample tank 130. The final elution sample tank 130 is then weighed.
This example also provides a method for detecting rare earth elements, which is to perform instrumental analysis on an eluted sample obtained by elution, specifically referring to example 1.
Comparative example 1
The comparative example provides a pretreatment method for rare earth element testing, which adopts an incomplete closed enrichment system, particularly refers to Jie et al 2017 NOBIAS PA1 chelating resin enrichment-ICP-MS quantitative determination of rare earth elements in offshore water bodies, and still adopts NOBIAS chelate-PA1 type resin.
The comparative example also provides a method for detecting rare earth elements, and the elution sample obtained by elution is subjected to instrument analysis, which specifically refers to example 1.
Comparative example 2
This comparative example provides a pretreatment method for rare earth element testing, which is substantially the same as example 1 except that: the NOBIAS latex-PA 1 type resin was replaced with RESpec resin.
The comparative example also provides a method for detecting rare earth elements, and the elution sample obtained by elution is subjected to instrument analysis, which specifically refers to example 1.
Comparative example 3
This comparative example provides a pretreatment method for rare earth element testing, which is substantially the same as example 1 except that: the NOBIAS chelate-PA1 type resin is replaced by solid phase extraction resin Chelex 100 chelating resin (Chelex 100 for short).
The comparative example also provides a method for detecting rare earth elements, and the elution sample obtained by elution is subjected to instrument analysis, which specifically refers to example 1.
Comparative example 4
This comparative example provides a pretreatment method for rare earth element testing, which is substantially the same as example 1 except that: the elution process does not introduce nitrogen to elute the pressure gas.
The comparative example also provides a method for detecting rare earth elements, and the elution sample obtained by elution is subjected to instrument analysis, which specifically refers to example 1.
Test example 1
The detection method in example 1 was evaluated: the blank was subjected to 5-time measurement in parallel, and 2% nitric acid (n ═ 5), the blank count and detection limit (3 σ) of the method were as shown in table 2, where n represents the number of samples.
The spiked recovery of the detection method in example 1 was determined using the spiked recovery method. The method comprises the following steps: 0mL (1ppb), 0.05mL (1ppb), 0.1mL (1ppb), 0.3mL (1ppb) and 0.1mL (10ppb) of the standard stock solutions of Y + REEs were sequentially added to a 15mL centrifugal tube containing 5 2mL seawater, and then the volume was adjusted to 10mL with ultrapure water, the pH was adjusted to 5.5 to 5.8, and the resin enrichment ICP-MS test was performed. The recovery rate of REEs by the analysis method established in the research is between 103 and 108 percent, and the result is shown in figure 2.
TABLE 2 blank average and detection limits
As can be seen from the detection results in table 2 and fig. 2, the detection method provided in the embodiment of the present invention is suitable for detecting Y + REEs in pore water and small-volume water (<5mL), and has high detection accuracy and an ideal recovery rate of the elements (103% to 108%).
Test example 2
The results of evaluation of the detection methods of comparative examples 1 to 4 by the method of test example 1 show that the recovery rates of REEs in comparative examples 1 to 4 are 94% to 106%, 80% to 120%, 80% to 88%, and 92% to 100%, respectively.
Therefore, the closed enrichment system provided by the embodiment of the invention can not only avoid the pollution of the external environment, but also be beneficial to further improving the recovery rate of the rare earth elements; the selection of the resin in the embodiment of the invention has a remarkable influence on the improvement of the recovery rate of the rare earth elements.
In summary, according to the pretreatment method for the rare earth element test provided by the invention, the enrichment process of the rare earth element is performed by using a closed pipeline, so that the pollution of the external environment is avoided; the pressure gas and the eluent are used for elution in parallel, the elution speed is high, the effect is good, and the accuracy of the subsequent detection process is improved.
The invention also provides a pretreatment device for testing the rare earth elements, which utilizes the sequential connection of the sample tank, the adsorption tube and the pump set to form an adsorption pipeline; an elution pipeline is formed by utilizing an elution liquid tank, an adsorption pipe and an elution sample tank which are sequentially connected. The rare earth element adsorption and elution processes are operated by independent and closed pipelines, so that the pollution of the external environment is avoided, and the detection rate is improved.
The invention also provides a method for detecting the rare earth element, which comprises an instrument analysis process and the pretreatment method; wherein the instrumental analysis process is to analyze elements in the elution sample obtained in the pretreatment method. The whole detection method has short detection period and high element recovery rate, and avoids the pollution of the external environment.
The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Claims (17)
1. A method for detecting rare earth elements in pore water is characterized by comprising an instrument analysis process and a pretreatment method; wherein, the instrument analysis process is to analyze elements in the elution sample obtained in the pretreatment method;
the pretreatment method comprises the steps of adopting a pretreatment device to carry out treatment, wherein the pretreatment device comprises a pump set, a sample tank for containing cleaning liquid or liquid to be adsorbed, an adsorption tube for containing resin, an elution sample tank for containing an elution sample and an elution liquid tank for containing solution for elution, wherein a pressure gas conveying pipeline is connected to the elution liquid tank, and the gas outlet end of the pressure gas conveying pipeline extends into the elution liquid tank;
the sample tank, the adsorption pipe and the pump set are sequentially connected to form a closed adsorption pipeline; the elution liquid tank, the adsorption tube and the elution sample tank are sequentially connected to form a closed elution pipeline;
the pretreatment method comprises the following steps:
filling resin for enriching rare earth elements into the adsorption tube, preparing a sample containing the rare earth elements into the to-be-adsorbed solution, introducing the to-be-adsorbed solution into the adsorption tube, enriching and then discharging;
introducing elution pressure gas into the elution liquid tank, introducing the elution pressure gas and the elution liquid into the adsorption tube to elute the resin, and then introducing the eluted solution into the elution sample tank;
the sample is sediment pore water, and the volume of the sample is less than 5 mL;
the pressure of the elution pressure gas introduced into the elution liquid tank is 4-6psi, and the resin is NOBIAS latex-PA 1 type resin.
2. The detection method according to claim 1, wherein a washing buffer is introduced into the adsorption tube to remove residual metal ions before elution is performed after the liquid to be adsorbed is enriched in the adsorption tube.
3. The method of claim 2, wherein the wash buffer is NH4AC buffer solution, and said NH4The concentration of the AC buffer solution is 0.04-0.06 mol/L.
4. The test strip of claim 1The method is characterized in that before the liquid to be adsorbed is enriched in the adsorption tube, the adsorption pipeline is cleaned by nitric acid cleaning liquid in the sample tank; then using NH4The adsorption line is purged with an AC buffer solution.
5. The detection method according to claim 4, wherein the NH is4The concentration of the AC buffer solution is 0.04-0.06 mol/L.
6. The detection method according to claim 1, wherein the pH of the liquid to be adsorbed is 5.5 to 5.8.
7. The detection method according to claim 6, wherein the solution to be adsorbed is prepared by acidifying with hydrochloric acid and then diluting with deionized water, and then using NH4The pH was adjusted with AC buffer solution.
8. The detection method according to claim 1, wherein the resin is washed after being filled in the adsorption tube and before being adsorbed.
9. The detection method according to claim 8, wherein the resin is washed by sequentially using HCl solution with concentration of 5.5-6.5N, ocean seawater with pH =1.8-2.2, HNO with concentration of 1.8-2.2N3Solution, HNO with concentration of 1.8-2.2N3The solution, deionized water and ocean water at pH = 1.8-2.2.
10. The detection method according to claim 8, wherein before the resin is filled in the adsorption tube, washing is performed a plurality of times with methanol and water, respectively.
11. The method of claim 8, wherein the resin is filled by gravity during filling of the sorbent tube, and wherein deionized water is driven through the resin when the fill is nearly full.
12. The detection method according to claim 1, wherein the instrumental analysis process is measured using an ICP-MS instrument.
13. The detection method according to claim 12, wherein an Apex nebulizer is used as the nebulizer of the ICP-MS instrument.
14. The detection device for testing the rare earth elements in the pore water is used for implementing the detection method according to any one of claims 1 to 13, and is characterized by comprising a pump unit, a sample tank for containing cleaning liquid or liquid to be adsorbed, an adsorption pipe for containing resin, an elution sample tank for containing an elution sample and an elution liquid tank for containing solution for elution, wherein a pressure gas conveying pipeline is connected to the elution liquid tank, and the gas outlet end of the pressure gas conveying pipeline extends into the elution liquid tank;
the sample tank, the adsorption pipe and the pump set are sequentially connected to form an adsorption pipeline;
the elution liquid tank, the adsorption tube and the elution sample tank are sequentially connected to form an elution pipeline.
15. The detection device according to claim 14, wherein a first multi-way valve and a second multi-way valve are mounted on a communication pipeline between the sample tank and the adsorption tube, and the pretreatment device further comprises a buffer tank;
the sample tank and the buffer liquid tank are communicated with the first multi-way valve, so that the sample tank is connected with the adsorption tube sequentially through the first multi-way valve and the second multi-way valve, and the buffer liquid tank is connected with the adsorption tube sequentially through the first multi-way valve and the second multi-way valve.
16. The detection device according to claim 15, wherein a third multi-way valve is mounted on a communication pipeline between the eluent tank and the adsorption tube;
the elution liquid tank is connected with the elution sample tank through the third multi-way valve, the adsorption pipe and the second multi-way valve in sequence to form an elution pipeline;
the sample tank is connected with the pump group through the first multi-way valve, the second multi-way valve, the adsorption pipe and the third multi-way valve in sequence to form an adsorption pipeline;
the buffer solution tank is connected with the pump group through the first multi-way valve, the second multi-way valve, the adsorption pipe and the third multi-way valve in sequence to form a buffer solution adjusting pipeline.
17. The sensing device of claim 16, wherein the first, second, and third multi-way valves are four-way valves.
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| CN112834488A (en) * | 2021-01-05 | 2021-05-25 | 包头钢铁（集团）有限责任公司 | Method for determining contents of lanthanum, cerium, praseodymium, neodymium, samarium, calcium and magnesium in iron ore |
| CN113049668B (en) * | 2021-02-24 | 2023-05-23 | 中科南京绿色制造产业创新研究院 | Dynamic separation process research and analysis system and method |
| CN113866253B (en) * | 2021-09-08 | 2024-03-19 | 中国辐射防护研究院 | Rapid analysis method for plutonium content in urine sample |
| CN114427031B (en) * | 2022-01-26 | 2022-12-13 | 江苏南方永磁科技有限公司 | High-purity rare earth metal recovery device taking rare earth metal slag as raw material |
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