CN102284275A - Preparation method of heavy metal ion solid-phase extraction agent - Google Patents

Abstract

The invention relates to a preparation method of a heavy metal ion solid-phase extraction agent. In the method, a multi-walled carbon nano-tube is used as a main body, a phenyliminodiacetic acid ligand is introduced to the surface of the carbon nano-tube by virtue of a mild diazotization reaction so as to obtain a phenyliminodiacetic acid modified carbon nano-tube; and the phenyliminodiacetic acid modified carbon nano-tube serving as a heavy metal ion solid-phase extraction agent is filled in a 6ml SPE (solid phase extraction) column, a mixed water sample containing Pb(II), Cu(II) and Fe(III) is dynamically enriched by using an SPE device, the adsorption rate reaches 95 to 97 percent when the pH is 6, and the recovery rate is more than 97 percent. The heavy metal ion solid-phase extraction agent has a mild and quick reaction and a high functional modification degree by using water as a solvent, and has the characteristics of capabilities of simultaneously adsorbing Pb(II), Cu(II) and Fe(III) in the water body, high adsorption capacity, strong interference resistance, recyclability and the like.

Description

A kind of preparation method of heavy metal ion solid extracting agent

Technical field

The present invention relates to a kind of preparation method of heavy metal ion solid extracting agent, specifically is the technology for preparing phenylimino oxalic acid modified carbon nano-tube by diazo-reaction.The heavy metal ion pre-separation beneficiation technologies field that belongs to trace in the fluid sample.

Background technology

At present, the harm of heavy metal is paid close attention to by the people more and more, and heavy metal is as the most dangerous pollutant of a class, serious ecological environment and the human beings'health safety of threatening.Because heavy metal has irreversibility and accumulation property, even under the situation of trace, also can produce adverse consequences, therefore, content of beary metal seems necessary further in concentration and separation and the testing environment effectively.

Solid phase extraction techniques (Solid phase extraction, be called for short SPE) be a kind of novel pre-separation beneficiation technologies that grows up the seventies in last century, be widely used in all trades and professions because have the following advantages: 1) organic solvent consumption is few, composition to be measured is in the SPE post after the enrichment, only eluant, eluent that need be few just can be the complete wash-out of composition to be measured in fixing mutually, and the consumption of organic solvent is well below traditional liquid-liquid extraction.2) can carry out the pre-separation of the purifying and the interfering component of sample,, select extractant targetedly for use in conjunction with the characteristics of composition to be measured, thereby the composition to be measured of enrichment selectively, also can allow interfering component be retained on the extractant, allow composition to be measured pass through, thereby separate interfering component.Therefore, the SPE technology can effectively be carried out sample purifying and interfering component pre-separation.3) enrichment multiple height, to environmental water sample, the SPE technology can be enriched to several milliliters to tens compositions to be measured to hundreds of ml samples, the enrichment multiple reaches tens of times to hundreds of times, and this advantage when concentration of component to be measured is low more, show obvious more.4) the SPE technology can be enriched in composition to be measured in the SPE post, is convenient to the storage of sample and transports, and is highly suitable for the spot sampling in the environmental monitoring.5) easily realize automation mechanized operation, energy and various detecting instrument such as ICP, HPLC etc. link to each other, and reach the purpose of rapid analysis.

Application SPE technology Preconcentration and Separation trace metal ion has obtained vast scientific research person's concern, Liu Yongwen etc. are with 2,6-dihydroxy benzenes-diazoamino azobenzene (DHDAA) and 2-thiuretic acid benzene diazoamino azobenzene (AMPDAA) modification Ambcrlitc XAD-4 pre-separation enrichment Cd (II), Co (II), Cu (II), Zn metal ions such as (II), and be used for gathering and measuring (the Liu Y of these ions of environmental water sample, Guo Y, Meng S, FengF, Chang X.Microchemical Atca, 2007,157:209.).Cr (III), Pb (II), Fe (III) that active carbon after the human ethylenediamine modifications such as Chang Xijun adsorbs in the water sample have simultaneously obtained good effect (Chang X J, Li ZH, Zou X J, et al.Analytica ChimicaActa, 2009,632:272-277).The development of SPE technology has promoted the SPE Development of Materials.

In recent years, CNT is because its excellent physicochemical properties have been subjected to extensive concern.Wherein huge specific area, excellent chemical stability, and easily advantage such as functionalization has CNT to become the prerequisite of SPE material.People such as Yan have obtained satisfied result (Y Liu, Y Li, X P Yan, Adv Funct Mater, 18 (2008) 1536-1543.) with the Cd (II) in the L-cysteine carbon nano tube modified absorption environmental water sample.Humans such as Cui three-(2-aminoethyl) amine modified carbon nano-tube, and with its solid extracting agent, adsorption capacity as Pb (II) reach 38mg/g (Y Cui, S Liu, et al.Microchim Acta, 2011, DOI10.1007/s00604-011-0601-8).

But above-mentioned two kinds material modified be by CNT by under hot conditions with strong acid reaction after, use the thionyl chloride chloride, obtain under the process conditions by acid amides reaction introducing part again, therefore there is severe reaction conditions, complex process, contaminated environment and can only adsorb shortcoming and defect such as single heavy metal ion.

Summary of the invention

The object of the present invention is to provide the preparation method of a kind of phenylimino oxalic acid chemical modification CNT (MWCNTs-PIAD), this MWCNTs-PIAD can adsorb contents of many kinds of heavy metal ion simultaneously as the heavy metal ion solid extracting agent, and synthesis step environmental protection, simple to operate.

In order to achieve the above object, the present invention is based on multi-walled carbon nano-tubes, diazo-reaction by gentleness is introduced phenylimino oxalic acid part on carbon nano tube surface, the MWCNTs-PIAD that obtains is as a kind of novel sorbing material of SPE, when this material is used for the heavy metal ion enrichment of environment water, when pH=6, the adsorption capacity of Pb (II), Cu (II), Fe (III) is reached maximum, be respectively 16.9mg/g, 30.5mg/g, 64.8mg/g.Its strong interference immunity simultaneously, the metal ion after the enrichment can be with rare nitric acid or hydrochloric acid wash-out, and the rate of recovery reaches more than 95%.

MWNCTs-PIAD synthetic method of the present invention is the benzoic acid modified CNT of first synthesizing amino (MWCNTs-PA), again synthesis of phenyl iminodiacetic acid modified carbon nanotube (MWCNTs-PIAD).Concrete technology is as follows:

The first step, be in 10% the sodium dodecyl benzene sulfonate aqueous solution in the ultrasonic weight percent concentration that is dispersed in down earlier with the 0.3-0.5g multi-walled carbon nano-tubes, add 1 of 740-760mg then rapidly, the 4-amino benzoic Acid, 480-500mg natrium nitrosum and 6-10ml HCl, behind 80 ℃ of stirring reaction 24h with 45 μ m filtering with microporous membrane, filter residue DMF supersound washing, there is not color until filtrate, use ethanol again, acetone and water wash respectively and obtain solid, and solid is spent the night 80 ℃ of vacuum drying, obtain the amino benzoic Acid modified carbon nano-tube, standby;

Second step, get the amino benzoic Acid modified carbon nano-tube 0.1-0.3g that the first step obtains, it is dispersed in the 300-500ml absolute ethyl alcohol, ultrasonic dispersion 30min, add 1-3g NaOH, add the 1.5-3.0g sodium chloroacetate behind 78 ℃ of heating 45min, use the 45mm filtering with microporous membrane behind the reaction 24h, filter residue does not have color with the DMF washing until cleaning solution, use ethanol afterwards more respectively, water and acetone washing, last 80 ℃ of vacuum drying get end product phenylimino oxalic acid modified carbon nano-tube;

160w 59Hz SK-3300H type Ultrasound Instrument (Shanghai High Kudos Science Instrument Co., Ltd.) is all adopted in above-mentioned ultrasonic employing;

It is pure that above-mentioned raw materials is commercially available analysis.

Major advantage of the present invention and effect are as follows:

1, compare with existing L-cysteine carbon nano tube modified and three-(2-aminoethyl) amine modified carbon nano-tube, because part is different to the metal-complexing performance, therefore, the present invention can be adsorbed Pb (II), Cu (II) and Fe (III) three metal ion species simultaneously, and synthesis step environmental protection, simple to operate.

2, because the present invention utilizes gentle diazo-reaction to introduce phenylimino oxalic acid part on carbon nano tube surface, the MWCNTs-PIAD that obtains, CNT has nanometer and the dual yardstick characteristics of micron, with it as modified support, both effectively utilize the advantage of its super large specific area, guaranteed the separability of material and collection property again.

3, product of the present invention is just effectively enriched with trace metal Pb (II), Cu (II), Fe (III) from water body at short notice, and material has also that absorption pH is moderate, and adsorption capacity is big, and antijamming capability is strong, many characteristics such as can utilize repeatedly again.

4, the product that the present invention is obtained is filled in the dynamic enrichment operation of carrying out actual water sample in the SPE pillar, for its practicability is laid a good foundation.

The specific embodiment

Instantiation is explained the synthetic and application in Pb (II), Cu (II), Fe (III) SPE in water body that relates to MWNCTs-PIAD in detail.

Embodiment 1:

The first step, amino benzoic Acid modified carbon nano-tube (MWCNTs-PA) synthetic.

Taking by weighing commercially available model is the multi-walled carbon nano-tubes 0.3-0.5g of M210, making it be dispersed in weight percent concentration under the 50Hz ultrasound condition is in 10% the sodium dodecyl benzene sulfonate aqueous solution, add 740-760mg 1 more rapidly, the 4-amino benzoic Acid, 480-500mg natrium nitrosum and 6-10ml HCl, 80 ℃ of stirring reaction 24h, reaction finishes back with 45 μ m filtering with microporous membrane, filter residue DMF supersound washing, do not have color until filtrate, use ethanol again, acetone and water wash respectively, 80 ℃ of vacuum drying are spent the night, and it is standby to obtain MWCNTs-PA;

In second step, phenylimino oxalic acid modified carbon nano-tube (MWCNTs-PIAD) is synthetic.Getting 0.1-0.3g MWCNTs-PA is dispersed in the 300-500ml absolute ethyl alcohol, ultrasonic dispersion 30min adds 1-3g NaOH, 78 ℃ of heating 45min, add the 1.5-3.0g sodium chloroacetate afterwards, reaction 24h, reaction finishes back 45mm filtering with microporous membrane, and filter residue does not have color with the DMF washing until cleaning solution, use ethanol afterwards more respectively, water and acetone washing, 80 ℃ of vacuum drying get end product MWCNTs-PIAD.

160w 59Hz SK-3300H type Ultrasound Instrument (Shanghai High Kudos Science Instrument Co., Ltd.) is all adopted in above-mentioned ultrasonic employing;

It is pure that above-mentioned raw materials is commercially available analysis.

Embodiment 2:

MWCNTs-PIAD30-50mg with embodiment 1 gained, be filled in the SPE pillar of 6mL, with the SPE device to 300-500mL contain Pb (II), Cu (II) and Fe (III), the mixed sample that the content of every heavy metal species ion is 1～5 μ g/L carries out dynamic enrichment, and with the HNO of 5mL 2M ₃Wash-out, adsorption rate all reach 95%-97%, and when mixed sample pH=6, all greater than 97%, and adsorption time only needs 15min to Pb (II), Cu (II), Fe (III) the heavy metal ion rate of recovery, and it is saturated just to reach absorption; Common ion does not influence the enrichment of Pb (II), Cu (II), Fe (III) in the interfering ion experiment discovery natural water, and the rate of recovery is all greater than 97%.

MWCNTs-PIAD to embodiment 1 gained carries out the adsorption capacity experiment, and the saturated extent of adsorption that draws Pb (II), Cu (II), Fe (III) is respectively 16.9mg/g, 30.5mg/g, 64.8mg/g.

The present invention has adopted portable solid-phase extractor (GE PSPE-01 goes up sea green Supreme Being Environmental Protection Technology Co., Ltd)

Annotate: be used to measure the content of Pb (II), Cu (II), Fe (III) in the example and the instrument of concentration is the inductively coupled plasma emission spectrometer of U.S. PE company.

Claims (1)

1. the preparation method of a heavy metal ion solid extracting agent is characterized in that:

The first step, earlier the 0.3-0.5g multi-walled carbon nano-tubes is dispersed in weight percent concentration is under ultrasound condition in 10% the sodium dodecyl benzene sulfonate aqueous solution, add 1 of 740-760mg then rapidly, the 4-amino benzoic Acid, 480-500mg natrium nitrosum and 6-10ml HCl, behind 80 ℃ of stirring reaction 24h with 45 μ m filtering with microporous membrane, filter residue DMF supersound washing, there is not color until filtrate, use ethanol again, acetone and water wash respectively and obtain solid, and solid is spent the night 80 ℃ of vacuum drying, obtain the amino benzoic Acid modified carbon nano-tube, standby;

Second step, get the amino benzoic Acid modified carbon nano-tube 0.1-0.3g that the first step obtains, it is dispersed in the 300-500ml absolute ethyl alcohol, ultrasonic dispersion 30min, add 1-3g NaOH, add the 1.5-3.0g sodium chloroacetate behind 78 ℃ of heating 45min, use the 45mm filtering with microporous membrane behind the reaction 24h, filter residue does not have color with the DMF washing until cleaning solution, use ethanol afterwards more respectively, water and acetone washing, last 80 ℃ of vacuum drying get end product phenylimino oxalic acid modified carbon nano-tube;

Above-mentioned ultrasonic employing 160w 59Hz SK-3300H type Ultrasound Instrument, Shanghai High Kudos Science Instrument Co., Ltd.;

Above-mentioned raw materials is that commercially available analysis is pure.