Composite material for purification of polluted aquatic environments, including radionuclides

 

(57) Abstract:

The invention relates to the treatment of aqueous media from radioactive contaminants by sorption and can be used in the process of operation of energy transport facilities. Technical result: complex extraction of radionuclides and oil from water at a preliminary processing tanks for storage of liquid radioactive waste (LRW), decrease the amount of radiation hazardous operations associated with the extraction and disposal of spent sorbent. This object is achieved in that the composite material including natural filler mordenite, additionally contains peat and polymer binder. As the polymer binder used ultra-high molecular weight polyethylene (mol.m. (1,5 - 4,0)106. Content, wt. %: filler mordenite 10 - 30, peat 87 - 67, binder ultra-high molecular weight polyethylene (mol.m. (1,5 - 4,0)1063 - 10. table 2.

The claimed technical solution relates to the field of processing of aquatic environments from radioactive contaminants by sorption and can be used in the process of operation of energy transport facilities. Wastewater from these facilities, the soda is a FL. Pre-cleaning of water storage tanks for liquid radioactive waste (LRW) from radionuclides of cesium and petroleum products should always be carried in closed containers storage for 2-3 months. Such pre-treatment can be performed floating on the surface of a sorbent selective for radionuclides of cesium and absorbing the oil.

In the prior art it is known that for water purification from radionuclides can be used peat [Kuznetsov, Y. A., Sepetkovski A. N., Trusov, A., Fundamentals of water purification from radioactive contamination. M: Atomizdat, 1974.]. The disadvantage of the sorption material is leached in acid and alkaline media, which leads to additional water pollution. The use of granulated peat does not give the desired result, as when operating in the aquatic environment of the peat pellets lose their mechanical strength due to the high swelling.

Known sorption-active material for water purification from oil products [F. Volkov Century, the Study of the processes of fibrous film and bulk products from ultra-high molecular weight polyethylene. Abstract. dis. on saisc. academic Art. K. T. N. St. Petersburg, 1994, reg. N 04.9.90 008 125.] with the ethylene (UHMWPE) with a molecular mass (MM) (1,5-4,0)106. This sorbent has a sorption capacity in relation to petroleum products to 6.5 kg per 1 kg of sorbent and positive buoyancy over 4 months. The sorbent is produced in the form of blocks of different shapes or granules. To the disadvantage of the sorption material is the inability to use it as an effective sorbent for complex extraction of radionuclides in the presence of petroleum products in the aquatic environment, since the rate of extraction of oil exceeds the rate of sorption of radionuclides.

The closest analogue to the claimed technical solution is a porous composite material [RF Patent N 2135278, MKI 6 B 01 J 20/18, G 21 9/12 F, C 02 F 1/28. Publ.27.08.99. The way sorption of the radionuclide cesium from aqueous media./ Goncharov, B. C., Bazan N. In., Dominican Century A. ] for treatment of polluted aquatic environments from radionuclides of cesium, including natural sorbent mordenite fractions 5-15 μm and a connecting propresidential taken in the ratio (15-85) - (85-15) wt.%. The sorbent is made in the form of blocks, which are placed in a storage tank waste. The disadvantage of this material is that you cannot use it for pre-treatment of water containing radionuclides of cesium and oil the NT should be introduced into the tank for several months prior to the processing of water on a regular wastewater treatment systems. Separate application of the sorbent for oil and cesium selective sorbent in this case is impractical, as it increases the amount of waste contaminated sorbents (solid radioactive waste), which requires additional cost in processing. In addition, the introduction of sorbent for oil and remove it after a quick removal of surface oil products (films), followed by the introduction and removal of the sorbent on the radionuclides cesium leads to two radiation hazardous operations instead of one. After removing the oil film from the surface, in the process of destruction of oil emulsions in water or changes in physico-chemical characteristics of water, adding any additional LRW oil can again gather on the surface of the water and should again be removed. Technological lack of material containing mordenite, is that it sinks to the bottom of the storage tank LRW, complicating its subsequent retrieval.

The technical result of the claimed invention is a complex extraction of radionuclides and oil from water at a preliminary processing of the storage capacities of the LRW.

Techn environments include natural filler mordenite, additionally contains peat, and as the polymer binder used ultra-high molecular weight polyethylene with a molecular weight of 1.5-4.0)106in the following, wt.%:

Filler - mordenite - 10-30

Peat - 87-67

Binder - ultra-high molecular weight polyethylene - 3-10

Composite material (KM) in the form of granules (e.g., spherical) with a mass of 10-15 g is placed in the storage capacity of LRW with radioactively contaminated water containing oil at a rate of 1 kg KM 1 m3water and is extracted from the tank in 2-3 months. During operation KM floats on the surface of the water absorbing surface oil film and removing radionuclides from the volume of water being treated.

Example 1

Obtaining sorption-active material for water purification from oil products and radionuclides is as follows. In a heated apparatus with a three-bladed stirrer [vasiltsov E. A., Ushakov Century, Apparatus for mixing liquid media: a reference guide. L.: Chemistry, 1972. - 464 S.] preparing a solution of UHMWPE concentration of 1 wt.%. As the solvent used paraffin (TU 6-09-3637-87). At 140oC and continuous stirring (150 rpm) in a solvent zagrujayetsya with increasing temperature up to 150oC for 9 min with constant stirring. Filler - peat is heated at 130oC for 60 minutes and Heated filler (peat) is loaded into the polymer solution at a temperature of 140oC in the amount of 0.9 kg Is mixing the composition at 25-30 rpm for 5 minutes the resulting composition is placed in the form and cooled at room temperature. The cooled composite for removal of paraffin is extracted hydrocarbon, C6-C10when the boiling temperature of the hydrocarbon. Then, a material drying at 70oC for 30 minutes Ready sorption-active material is a composite with filler content (peat) 90 wt.% and the content of the binder (UHMWPE) 10 wt.%.

Example 2

Obtaining sorption-active material for water purification from oil products and radionuclides is as follows. In a heated apparatus with a three-bladed stirrer [vasiltsov E. A., Ushakov Century, Apparatus for mixing liquid media: a reference guide. L.: Chemistry, 1972. - 464 S.] preparing a solution of UHMWPE concentration of 1 wt.%. As the solvent used paraffin (TU 6-09-3637-87). At 140oC and continuous stirring (150 rpm) in a solvent is carried out by increasing the temperature to 150oC for 9 min with constant stirring. Fillers - peat and mordenite are heated at 130oC for 60 minutes Warm fillers (peat and mordenite) is loaded into the polymer solution at a temperature of 140oC the number of 4.35 kg of peat and 0.5 kg of mordenite. Is mixing the composition at 25-30 rpm for 5 minutes the resulting composition is placed in the form and cooled at room temperature. The cooled composite for removal of paraffin is extracted hydrocarbon 6-C10when the boiling temperature of the hydrocarbon. Then, a material drying at 70oC for 30 minutes Ready sorption-active material is a composite with filler contents 97 wt. % (peat - 87 wt.%. and the mordenite - 10 wt.%.), and the content of the binder (UHMWPE) 3 wt.%.

It is proposed to introduce the following notation for floating composite material - PCM UHMWPE wt.% + peat wt.% + mordenite wt.% (for example, PCM 3% + 87% + 10% means that the porous composite material, the binder content is 3 wt.%, the content of the peat - 87 wt.%, the content of the mordenite - 10 wt.%).

Check sorption activity PKM carried out in model conditions. Chemical SOS is ammonia). For sorption of caesium radionuclides used radioactive label cesium-137 (without media). Specific volume activity of the solution was 3,6106-5Ku/L. In the case of water, oil contaminated in the model water was applied oil Taj-17 in the amount of 0.05 g (concentration 1 g/l) and the solution was shaken for 10 minutes to obtain emulsion. The PCM samples having a mass of 0.05 g, was placed in buxy with 50 ml of a model of the aquatic environment. The solution in the tube was not mixed. After 24 hours the solution was additionally added oil Taj-17 in the amount of 0.05 g to check the health of the sorbent with respect to petroleum products throughout the operating time. After a certain period of time, samples of the solution were selected on radiometrically, and the sorbent was determined by water absorption and sorption capacity in relation to petroleum products. Water absorption and sorption capacity in relation to petroleum products was determined by the gravimetric method [Lurie Y. Y. Analytical chemistry of industrial wastewater. M.: Chemistry, 1984. - 448 C.]. The results are presented in table. 1.

Measurement of the activity of the sample was performed using Ge (Li) detector in the composition of Ganja - of 2.7 Kev at E=1,63 MeV. To suppress background radiation detector is surrounded by a lead shield. In such conditions, the limit of detection of activity of the sample cesium-137 with 95% probability is 1 Bq with exposure time of 1 h Spectra were recorded by a multichannel analyzer, the exposure time is chosen 10 (30) min [RF Patent N 2135278, MKI 6 01 J 20/18, G 21 9/12 F, C 02 F 1/28. Publ. 27.08.99. The way sorption of the radionuclide cesium from aqueous media./ Goncharov, B. C., Bazan N. In., Dominican Century A. ].

The results of the measurements was calculated purification coefficient (K) and the coefficient of the distribution of radionuclides between water and the sorbent (Kp). The calculation was carried out according to the formula:

< / BR>
< / BR>
where JRefand JKon- the initial and final (at the time of sampling) activity of the aquatic environment, Bq/DM3; V is the volume of the water environment, cm3; m is the mass of sorbent, g

In our experiment . There were three series of experiments. Results the efficiency of sorption of cesium-137 from the water environment (average value) are presented in table.2.

As can be seen from the table. 2, the sorbent p/p-1 (analog) shows the low efficiency of radionuclides of cesium,pdoes not exceed 400 when the duration of the cleanup for 58 days. BB is m it should be noted, the increase in the content of the mordenite in the composite over 30% has little effect on the cleaning efficiency. The duration of cleanup over 38 days practically does not increase the cleaning efficiency of the RMB, this is especially noticeable on the sorbents containing mordenite 30% and above. There is no difference in the efficiency of PKM cleaning water contaminated with petroleum products without them.

Sorbent p/p-9 (prototype), located at the bottom of the tube, showing the cleaning efficiency comparable with the effectiveness of treatment using PCM with a 30% content of the mordenite.

During preliminary treatment of LRW sorbent, manufactured in the form of granules, is loaded in a storage tank. During the whole operation time (2-3 months) PCM is located on the surface of the water. After placing sorbent for the contaminated water surface is active absorption of mineral oil. Within 25-30 minutes is reached the value of sorption of oil in its excess or cleaning the surface of the water in excess of the sorbent. The salt content of the water does not affect the process of its purification from petroleum products by this sorbent. Sorption of radionuclides occurs during the entire operating time of the sorbent. If additionally the lnoe value sorption. Re-sorption of oil does not affect the water treatment process from radionuclides. After 2-3 months, the RMB is collected from the water surface the net and make his disposal.

Industrial tests were conducted confirmed the efficiency of water purification from radionuclides of cesium and petroleum sorbent of the following composition, wt.%: UHMWPE - 3, peat - 67 and mordenite - 30.

Based on the above conclusions can be drawn:

most effective for water treatment containing oil products, porous composite materials containing 3% UHMWPE, 67-87% peat, 10-30% of mordenite;

the duration of the sorbent in water treatment is not less than one and a half months;

when the ratio (i.e. 1 kg of sorbent per 1 m3processed LRW) coefficient of water purification is 17-20, and the distribution coefficient Kp16000-20000.

Composite material for purification of polluted aquatic environments, including radionuclides, including natural filler mordenite, wherein the material further contains peat, and as the polymeric binder is ultra-high molecular weight polyethylene (mol.m. (1,5 - 4,0)106in the following content of components, m is mol.m. (1,5 - 4,0)106- 3 -10

 

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FIELD: sorbents.

SUBSTANCE: invention provides an improved adsorbent to remove impurities form various hydrocarbon streams. Adsorbent contains zeolite, alumina, and an additional metal oxide, at least 10 mol % of metal in the metal oxide being based on stoichiometric amount of metal required to compensate negative charge of zeolite lattice. Resulting adsorbent containing zeolite X, aluminum oxide, and sodium is successfully used to treat ethylene stream to liberate the latter from CO2, H2S, methanol, and other sulfur- and oxygen-containing compounds.

EFFECT: expanded hydrocarbon purification possibilities.

6 cl, 4 tbl, 11 ex

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