RU2543184C2 - Synthetic radioactive nanodiamond and method for production thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: synthetic radioactive nanodiamond consists of particles with an average diameter of not more than 100 nm and contains metal-containing radioactive impurities in amount of 0.04-1.24 wt %, with γ-radiation dose rate of less than 180 mcSv/h, γ+β-radiation dose rate of less than 720 mcSv/h. The radioactive nanodiamond is obtained by irradiating synthetic nanodiamonds, which contain metal-containing impurities, with neutron flux with neutron fluency of 1.4-1.46·10¹⁹ neutrons/cm².

EFFECT: technique for producing a radioactive nanodiamond is simple, safe, reliable and enables to set up industrial production.

2 cl, 8 tbl, 5 ex

Description

The invention relates to the field of inorganic chemistry of carbon, namely to cubic modification of carbon having superhard material properties and radioactivity, and the technology for its preparation.

DNDs are obtained by explosive decomposition of carbon-containing explosives (BB) with a negative oxygen balance from part of the released carbon in the form of nanodiamonds (size from 3 to 11 nm) as a result of chemical and physical processes behind the detonation wave front. Depending on the production method, DNDs contain various metal-containing impurities, some of which can be removed during chemical cleaning, and some remain unremovable as internal inclusions in primary indestructible aggregates, the size of which is 20-30 nm. Metal-containing impurities are technogenic in nature (the material of the walls of the explosive chamber, conductive wires, detonator capsule, impurities to the initial explosives).

Static synthesis nanodiamonds HA-AFM (particle size 100 nm) are obtained by crushing conventional synthetic diamond micropowders with subsequent classification in an aqueous or gaseous medium. Since NA-AFM is obtained in the presence of metal catalysts (Ni-Mn, Fe-Co, Cu), some of them are always contained as unremovable internal inclusions (up to 2.5% wt.). A certain amount of metal enters the NA-AFM from crushing and scattering devices.

Two stable carbon isotopes are known: ¹² C (~ 98.9%) and ¹³ C (~ 1.1%). Of the radioactive isotopes of carbon, ¹⁴ C with a half-life of T _½ = 5.6 · 10 ³ years is most important.

Given the usually very small amounts of nanodiamonds used in medicine and composites (0.001-0.3% by weight), they are almost impossible to diagnose. Only radioactive nanodiamonds (R-DND or R-HA-ACM) would be indispensable for diagnosis and use for research and industrial purposes, especially in medical practice.

State of the art

DND and NA-AFM are widely known and studied very deeply [V.Yu. Dolmatov. Detonation nanodiamonds. - SPb .: Publishing house of NPO Professional, 2011, 534 p .; The physical properties of diamond. Handbook, ed. N.V. Novikova. - Kiev: Naukova Dumka, 1987, 190 pp.]. It is known that it is almost impossible to obtain even ¹⁴ C irradiation of diamond. Yes, and there is no point in this, because its half-life is very long. ¹⁴ C, in fact, cannot be a full-fledged marker of DNA or HA-AFM, especially in medicine.

DNDs are individual particles combined into primary clusters of 5 crystallites [A.N. Ozerin, E.S. Kurkin, V.Yu. Dolmatov. Study of the structure of detonation synthesis nanodiamonds by X-ray diffraction, Crystallography, 2008, vol. 53, No. 1, pp. 80-87]. The latter, in turn, form indestructible aggregates of 9-10 clusters. Further, quite easily destructible aggregates are formed.

Upon receipt of DND, the so-called detonation diamond-containing charge (AS) is first formed, including 40-50% of the DND itself, ~ 40-50% of non-diamond carbon and ~ 10% of non-combustible impurities. The latter are, as a rule, a wide range of metal oxides and carbides, namely: Na, Mg, Al, Si, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, W, V.

Known methods of exposure to various materials using neutron radiation from industrial nuclear reactors.

The radiation energy is many times higher than the chemical bond energy. The action of radiation on a solid causes processes associated with modifications of the chemical composition or structure.

Solids have the ability to maintain thermodynamically unstable disturbances in chemical composition and structure for a long time. By the accumulation of such disturbances under the influence of radiation, some properties of a solid can be regulated. Under the influence of radiation causing nuclear reactions, it is possible to introduce microimpurities of neighboring elements into a solid body. This method of strict dosing of microimpurities can be effective for changing in the right direction the composition of the starting material.

Known technology for nuclear alloying of semiconductor materials in industrial production on power reactors such as RBMK. During the nuclear doping of silicon when it is placed in the neutron field of the reactor, part of the silicon nuclei is converted to the nuclei of the dopant of phosphorus [Smirnov L.S. Doping of semiconductors by nuclear reaction method. - Novosibirsk: Nauka, 1981]:

The ³⁰ Si nuclei, absorbing thermal neutrons with the emission of γ radiation, are converted into the nuclei of the unstable isotope ³¹ Si, which decays after 2.62 hours with the emission of β particles, forming nuclei of the dopant of phosphorus ³¹ P. The distribution of the nuclei formed corresponds to the distribution of the thermal neutron fluence by volume of silicon ingots.

In US Pat. RF No. 2193609 [BI No. 33, 2002] describes an improved method for neutron-transmutation doping of silicon, including irradiation with a neutron flux according to the dose-time schedule of a container with silicon ingots in the channel of a nuclear reactor, while the averaged neutron fluence is controlled using a neutron chamber and vertical assemblies composed of discrete current sensors.

In US Pat. RF No. 2172533 [BI No. 23, 2001] describes a method for producing a carbon-14 radionuclide by irradiating a mixture of calcium and sodium nitrates purified from impurities. The nitrate mixture is melted at 250-500 ° C, cooled, crushed and loaded into a container. After irradiation in a neutron flux, the lid of the container is pierced and served in portions through the holes of HNO ₃ to dissolve the irradiated substance, while simultaneously heating the container to 150-200 ° C. The resulting gaseous carbon-14 compounds are periodically blown out of the container and sent for processing. Carbon-14 is widely used in the form of labeled organic compounds, as well as in sources of β-radiation.

At the moment, there is no information on nanodiamonds (and other diamonds as well) having the properties of radioactive materials.

Disclosure of invention

The basis of the invention is the task of creating a radioactive nanodiamond, thanks to this unique ability, including inclusion in a variety of composite materials and coatings, for use in medical practice, which would be obtained by a simple technology characterized by relative safety, reliability, improved technical and economic and environmental parameters and allowing to organize on its basis the industrial production of the inventive nanodiamond material.

The problem is solved in that as the claimed material is proposed synthetic radioactive diamond, consisting of particles whose average diameter does not exceed 100 nm, containing metal-containing radioactive impurities in an amount of 0.04-1.24% wt., With a dose rate of γ-radiation less than 5.0 μR / s (180 μSv / h), dose rate of γ + β radiation less than 20 μR / s (720 μSv / h).

Diamond ash (metal-containing impurities) is due to the presence of inorganic impurities associated with the peculiarities of its production and is due to the presence of oxides and carbides of iron, salts of copper and nickel, compounds of calcium, aluminum, silicon, titanium, chromium, sodium, tungsten, which is the basis for the formation of radioactivity of nanodiamonds and is not an obstacle to the use of the claimed material in various fields of application (medicine, polymer chemistry, composite materials).

The problem is also solved by the fact that the inventive radioactive nanodiamonds are obtained by irradiating synthetic nanodiamonds, including metal-containing impurities in an amount of 0.04-1.24% by weight, by a neutron flux with a neutron fluence of 1.4-1.46 · 10 ¹⁹ neutrons / cm ² .

The inventive radioactive nanodiamond is a powder from light gray to black in color with the size of individual particles from 2 to 100 nm, determined by light scattering and x-ray diffraction analysis. The specific surface area, determined using the Brunauer-Emmett-Teller isotherms from the thermal desorption of argon, has a value of 200 to 450 m ² / g for DND and 20 to 60 m ² / g for NA-AFM. By analyzing the IR absorption spectrum of the R-DND and R-HA-ACM samples, absorption bands characteristic of carbonyl = CO, carboxyl = COOH and hydroxyl-CO groups were found.

Thus, the inventive radioactive diamond material has in comparison with the closest material, namely, the original DND and NA-AFM, radioactivity with a dose rate of γ radiation of less than 5.0 μR / s (180 μSv / h) and dose rate γ + β-radiation of less than 20 μR / s (720 μSv / h), which allows it to be effectively used in medicine (real-time determination of the concentration and amount of R-DNA in the body, the place of elimination from the body), in polymer chemistry (additional crosslinking polymer chains), in composite materials.

The appearance of the radioactivity of nanodiamonds is due to a specific method of its production by irradiation in a nuclear reactor with a certain neutron fluence, and the effect of radiation affects unremovable metal-containing impurities in nanodiamonds.

The essence of the method is illustrated by examples of its implementation.

Example No. 1.

In 4 quartz glass ampoules, 4 samples of detonation nanodiamond powder (DND-STP) produced by the Electrokhimpribor combine (Table 1) were placed and sealed.

Table 1 The weight of the ampoules with DND-STP powder (bulk density 0.38 g / cm ³ , metal-containing impurities - 1.24% wt.) Ampoule no. Ampoule mass with powder, g Powder mass, g one 2,2347 0.3029 2 2.1721 0.3046 3 2,1034 0.3065 four 2,1041 0,3004

Ampoules from No. 1-4 were irradiated in the reactor of the 4th power unit of the Leningrad NPP from 10/04/2010 12 ¹⁵ to 10/06/2010 12 ³⁰ in a special cooled channel. The average power of a fuel assembly (fuel assembly) in the immediate vicinity of the irradiation channel was 2.35 MW.

For standard irradiation conditions in the channel under consideration (the average fuel assembly power is 2.27 MW), the neutron flux density reduced to a thermal point is 8.1 · 10 ¹³ cm ^-2 · sec ^-1 .

Thus, during the irradiation, the neutron fluence amounted to:

8.1 · 10 ¹³ cm ^-2 · s ^-1 · 2.35 MW / 2.27 MW · (2 · 24 · 3600 + 900) s = 1.46 · 10 ¹⁹ neutrons · cm ^-2 .

Assessment of radiation dose rate from ampoules with DND powder. The measurement date is October 13, 2010 (exposure 7 days after the end of irradiation).

The mass of the powder in an aqueous ampoule is 0.3 g.

The dose rate of γ-radiation (1 cm from the ampoule) is 144 μSv / h when measuring DRG-05M with a filter. The dose rate of γ + β radiation (1 cm from the ampoule) is 648 μSv / h when measuring DRG-05M without a filter.

Spectrometric measurements of ampoules No. 1 and No. 2 using a semiconductor Ge-Li detector. Date of measurement - 10/18/2010

table 2 Most likely radionuclides after exposure Radionuclide Activity in ampoule, Ki Note Cr-51 1.8 · 10 ^-6 The main radionuclide present Hf-181 2.4 · 10 ^-8 Identified with high confidence. Sb-122, Sb-124, Zr-95 ≤1 · 10 ^-8 Present with a probability of 50%

Below is the elemental composition of non-removable, mainly metal-containing, impurities in the initial DND (Table 3).

Table 3 The elemental composition of non-removable impurities in chemically purified DND-STP Element Content, ppm Content,% wt. Na 156 0.0156 Mg 133 0.0113 Al 60 0.0060 Si 553 0,0553 Ca 238 0,0238 Ti 96 0.0096 Cr 5146 0.5146 Mn 60 0.0060 Fe 702 0,0702 Ni eleven 0.0011 Cu 35 0.0035 S 21 0.0021

A comparison of Tables 2 and 3 shows that the source of the Cr-51 radionuclide formation is the Cr-50 isotope (4.35% content in elemental chromium); radionuclide Hf-181 - stable isotope Hf-180 (content of 35.10% in elemental hafnium, a chemical analogue of titanium); other chemical impurities - iron, titanium, aluminum can also form long-lived radionuclides, such as Fe-59, Sc-46, Co-60.

Examples No. 2-5.

The following types of nanodiamonds were used as starting products (Table 4).

Table 4 Source nanodiamonds Ampoule no. Type of nanodiamonds and its manufacturer The mass of nanodiamond powder, g Example No. 2-1 Detonation, CJSC Diamond Center (Russia), undermining in the environment of an aqueous solution of urotropin (complexing agent) 0.2736 2 2-2 0.2050 3-1 Detonation, ZAO Alit (Ukraine), standard charge detonation in water 0.3741 3 3-2 0.3585 4-1 Detonation, made in prof. Osawa (Japan), non-aggregated DNA 0.5606 four 4-2 0.4548 5-1 Static Synthesis Nanodiamond (0.1 / 0), SAKID LLC (Russia), (NA-AFM) 1,0119 5 5-2 0.9386

All 8 ampoules (Table 4) were irradiated in the reactor of the 4th power unit of the Leningrad NPP from 01/11/2011 12 ¹⁵ to 01/13/2011 12 ²⁰ in a special cooled channel located in cell 34-57. During irradiation, the reactor was at a nominal power level of 1020 ± 10 MW el. The average fuel assembly power in the immediate vicinity of the irradiation channel was 2.27 MW.

During the irradiation, the neutron fluence was 8.1 · 10 ¹³ cm ^-2 · s ^-1 · (2 · 24 · 3600 + 300) s = 1.40 · 10 ¹⁹ neutrons · cm ^-2

Evaluation of the radiation dose rate from ampoules with nanodiamond powder:

First measurement date: 02/01/2011, 14 ⁰⁰ (exposure time 19 days).

The mass of powder in one ampoule is from 0.2050 to 1.0119 g.

The dose rate of γ-radiation (1 cm from the ampoule) when measuring DRG-05M with a filter and the dose rate of γ + β-radiation (1 cm from the ampoule) when measuring DRG-05M without a filter are presented in Tables 5, 6, 7.

Table 5 Radiation dose rate as of February 1, 2011, 14 ⁰⁰ (exposure 19 days after the end of irradiation) Ampoule no. Fireproof impurities,% wt. The dose rate of γ-radiation, μSv / h (average) % γ-radiation from the total γ + β-radiation The dose rate of γ + β radiation, μSv / h (average) 2-1 and 2-2 0,07 13.68 43 31.86 3-1 and 3-2 0.34 14.22 38 37.08 4-1 and 4-2 0.79 124.20 thirty 410.40 5-1 and 5-2 0.85 160,20 35 459.00

Table 6 Radiation dose rate as of May 10, 2011, 11 ⁰⁰ (exposure 117 days after the end of irradiation) Ampoule no. Fireproof impurities,% wt. The dose rate of γ-radiation, μSv / h (average) % γ-radiation from the total γ + β-radiation The dose rate of γ + β radiation, μSv / h (average) 2-1 and 2-2 0,07 3.24 72 4,50 3-1 and 3-2 0.34 4.68 76.5 6.12 4-1 and 4-2 0.79 30.24 64.6 40.68 5-1 and 5-2 0.85 32,4 54 60.12

Table 7 Radiation dose rate as of August 28, 2011, 11 ⁰⁰ (exposure 227 days after the end of irradiation) Ampoule no. Fireproof impurities
% wt. The dose rate of γ-radiation, μSv / h (average) % γ-radiation from the total γ + β-radiation The dose rate of γ + β radiation, μSv / h (average) 2-1 and 2-2 0,07 0.61 70.8 0.86 3-1 and 3-2 0.34 1.22 73.0 1,66 4-1 and 4-2 0.79 7.74 74.1 10.44 5-1 and 5-2 0.85 11.20 64.8 17.28

Below is the elemental composition of non-removable, mainly metal-containing, impurities of the initial DND (examples Nos. 2, 3 and 4) and NA-AFM (example No. 5) (Table 8).

Table 8 The elemental composition of non-removable impurities in chemically purified DND and NA-AFM Element Project 2 DND, Diamond Center CJSC (Russia) Project 3 DNA, ZAO Alit (Ukraine) Pr. 4 BOTTOM, prof. Osawa (Japan) Project 5 NA-ASM, LLC SAKID (Russia) content in ppm % wt. ppm % wt. ppm % wt. ppm % wt. Na 9 0,0006 29th 0.0029 809 0,0809 8 0,0008 Mg - - 26 0.0026 104 0.0104 eighteen 0.0018 Al - - 326 0,0326 243 0,0243 eleven 0.011 Si 99 0.0066 492 0,0492 571 0,0571 344 0,0344 K - - thirty 0.0030 38 0.0038 - - Ca 71 0.0054 119 0.0119 220 0.0220 58 0.0058 Ti 46 0.0035 208 0,0208 936 0.0936 - - Cr - - 74 0.0074 264 0.0264 16 0.0016 Mn - - 2 0,0002 10 0.0010 2406 0.2406 Fe 160 0.0123 450 0.0450 1109 0,1109 255 0,0255 Ni - - 3 0,0003 26 0.0026 2710 0.2710 Cu 9 0,0006 64 0.0064 32 0.0032 - - Zn - - 77 0.0077 - - 3 0,0003 Zr - - 3 0,0003 12 0.0012 - - W - - 210 0.0210 603 0,0603 - - S - - 8 0,0008 12 0.0012 - - V - - 17 0.0017 65 0.0065 - - Pb - - 112 0.0112 - - - - Sn - - - - four 0,0004 Co - - 6 0,0006

From a comparison of Table 8 with Table 5, 6 and 7, it can be seen that the resulting radioactivity of DND and NA-AFM after irradiation with neutrons can be attributed to radionuclides formed from Na, Ca, Ti, Fe, Al, W, V, Cu.

This radioactive diamond material is intended primarily for use in medicine. When using DND as an anti-cancer agent [Pat. RF №2203068, prior. 04/12/2001, registered. 04/27/2003, BI No. 12] it is impossible to determine in a living organism the places of accumulation of DND, the effectiveness of exposure to cancer cells, the ratio of the amounts of DND in places of elimination from the body in real time. Only the use of radioactive DNA makes this possible.

R-DND and R-HA-ACM can also be used for enhanced crosslinking of polymeric materials, to create all kinds of composite materials.

Claims (2)

1. A synthetic nanodiamond, consisting of particles whose average diameter does not exceed 100 nm, a part of the surface of which contains functional groups, including metal-containing radioactive impurities in an amount of 0.04-1.24% by weight, with a dose rate of γ radiation of less than 180 μS3v / h and a dose rate of joint γ + β radiation of less than 720 μS3v / h. 2. A method of producing a radioactive synthetic nanodiamond by irradiating synthetic nanodiamonds, including metal-containing impurities in an amount of 0.04-1.24% by weight, by a neutron flux with a neutron fluence of 1.4-1.46 · 10 ¹⁹ neutrons / cm ² .