RU2340022C1 - Method for obtaining sorbent for environment treatment - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention concerns obtaining sorbent for environment treatment of radioactive and toxic contamination, using crushed iron magnesium concretions and can be applied in radioactive and industrial sewage and air and air-vapour medium treatment. Method of obtaining sorbent for environment treatment of radioactive and toxic contamination, using crushed iron magnesium concretions involves iron magnesium concretion crushing and linking to bentonite. Obtained material is granulated to the size under 0.1 and dried at 25°C.

EFFECT: high efficiency of radioactive and industrial sewage treatment process involving easily available material.

2 cl, 2 dwg, 1 tbl

Description

The invention relates to a method for producing a sorbent for cleaning the environment from radioactive and toxic contaminants based on crushed ferromanganese nodules and can be used both in the processing of liquid radioactive waste and in the treatment of industrial wastewater, and for the purification of air and vapor-air media.

The known method for the catalytic decomposition of nitrous oxide in its pure form or in a mixture of gases according to the patent of Germany No. 3543640, IPC B01D-53/56, publ. 1987, provides for the use of palladium-containing catalysts. The disadvantage of this method is the complexity of the preparation and regeneration of the used catalysts and the use of expensive equipment with low process efficiency.

According to the patent of Germany No. 3634553, IPC B01D-53/56, publ. 1988, to reduce the content of nitrogen oxides in flue gases, lumpy manganese and manganese-containing marine nodules are used. The disadvantage of this method is the low strength characteristics of manganese-containing nodules.

According to the patent of the Russian Federation No. 2062518, IPC G21F 9/12, publ. 1996, adopted as a prototype, a method for cleaning solutions containing radioactive and toxic contaminants based on ground ferromanganese nodules to a particle size of 0.1-3.0 mm, heat-treated at 750-850 ° C. The disadvantages of this method are the increased energy consumption in the process of heat treatment of nodules, as well as a greater likelihood of desorption of components from the phase of nodules.

The technical result is the elimination of these shortcomings, namely the creation of an effective process for cleaning easily accessible material from liquid radioactive waste and industrial wastewater, as well as the purification of air and vapor-air environments. A feature of this material is the possibility of using modified ferromanganese nodules for cleaning components of rocket fuels from impurities of total nitrogen oxides and asymmetric dimethylhydrazine.

The technical result is achieved by the fact that in the method for producing a sorbent for cleaning the environment from toxic and radioactive contaminants according to the invention, ground ferromanganese nodules are bonded with bentonite, granulated to a particle size of not more than 0.1 mm and dried at a temperature of 25 ° C.

As a sorbent, ferromanganese nodules of the Gulf of Finland are used.

The method is illustrated in the table and drawings. The table shows the values of the specific surface area of simple and modified ferromanganese nodules, Fig. 1 shows sorption curves of nitrogen tetroxide with various sorbents, and Fig. 2 shows sorption curves of asymmetric dimethylhydrazine with various sorbents.

The method is as follows.

Ferromanganese nodules, for example, nodules in the Gulf of Finland, after crushing and grinding to an air-dry state, are associated with bentonite, obtaining granules with a particle size of less than 0.1 mm, and dried in air at a temperature of 25 ° C. Bentonite is a colloidal clay with pronounced sorption and plastic properties. When using this binder, the capacitive and strength characteristics of the sorbent are improved, which is explained by an increase in the specific surface during the grinding process.

The specific surface of the sorbents was determined by the Brunauer-Emmett-Teller method using liquefied air and precision weights. The results of measuring the specific surface are presented in the table.

Table
The results of determining the specific surface of the LMC Sorbent Specific surface, m ² / g LMC (-1.6 + 1.0) 112.6 LMC (-0.4 + 0.1) 123.7 LMC (-0.3 + 0.1) 129.9 LMC (-0.2 + 0.1) 135.34 FMCs bound by bentonite (<0.1 mm) 143.67

To confirm the possibility of treatment with modified nodules of radioactive and industrial waters, the values of the static ultimate capacities for strontium and nickel, as well as the dynamic capacity for iron (2+), were obtained.

Sorption of strontium and nickel separately was studied under static conditions on model solutions with the ratio of the volume of the liquid phase to the mass of solid V / m = 10 ml · g ^-1 and the weight of the weight of LMCs associated with bentonite, 5 g. The value of the capacities was determined by the difference in the concentrations of the initial C ₀ and equilibrium C _eq solutions. A model solution of the corresponding cation was mixed with a weighed sample of modified LMC magnetic stirrer at a stirring speed of 400 rpm ^-1 to equilibrium. The time to establish equilibrium corresponding to a constant concentration of the solution was 5–6 hours; in the experiments, the contact time of the phases was set to at least 10 hours. The equilibrium concentration of the components was determined by photometric methods. The values of the capacitance for strontium were determined experimentally 0.97 eq · kg ^-1 , nickel 2.058 eq · kg ^-1 .

The behavior of iron (2+) was studied under dynamic conditions in a column with a layer height of 300 mm and a diameter of 16 mm, the sorbent volume in the columns was 60 ml. The dynamic capacity to breakthrough (DE) of iron (2+) with a concentration of 0.1 mg / L (3.57 mEq / L) (MPC for fishery reservoirs) was determined by analysis of 50 ml samples taken at the outlet of the column. In the selected samples of the solution, the total iron content (2+) and (3+) were determined by spectrophotometric method. The initial concentration of iron (II) at the inlet to the column when determining the DE was 0.026 eq / L (0.728 g / l), and when determining the PDE 0.134 eq / L (7.504 g / l). The dynamic capacity of the modified nodules turned out to be 4.1–4.4 eq / kg, whereas the simple ones were 0.5–3 eq / kg.

To confirm the possibility of sorption of gas mixtures, a unit was assembled, including a gas-dynamic unit (GDU), which allows you to set the concentration of impurities in the vapor-air mixture (PVA) from 10 ^-6 to 10 ^-3 mg / l, a gas photospectrometric colorimeter (GFSK) for analytical control of PVA and filter filled with sorbent. The experimental design is shown in Figure 1. The measurements were carried out in 5 consecutive series according to the following scheme: air without impurities, PVA mixed with nitrogen or asymmetric dimethylhydrosine (UDMH), PVA with nitrogen and UDMH passed through a sorbent under normal climatic conditions (ambient temperature 25 ° C, pressure 760 mm, humidity 85%).

The concentration of nitrogen impurities and UDMH in PVA was established constant and amounted to 1.00 · 10 ^-3 mg / L.

As sorbents, silica gel, anthracite, expanded clay, artificial sorbent of the Aquamandix brand, LMC of various granular composition and LMC modified with bentonite were used. It was shown that not one of the filters used, except for nodules associated with bentonite, did not completely purify the PVA from the vapor of nitrogen oxides (Figure 1) and UDMH (Figure 2) to the level of maximum permissible concentration.

In the method, nodules of not only the Gulf of Finland, but also oceanic nodules, as well as nodules of the Baltic Sea, can be used.

Thus, in the inventive method, a high efficiency of the process of cleaning easily accessible material from liquid radioactive waste and industrial wastewater, as well as the purification of air and vapor-air environments, is achieved. A feature of this material is the possibility of using modified ferromanganese nodules for cleaning components of rocket fuels from impurities of nitrogen oxides and asymmetric dimethylhydrazine.

Claims (2)

1. A method of producing a sorbent for cleaning the environment from radioactive and toxic contaminants based on crushed ferromanganese nodules, characterized in that the crushed ferromanganese nodules are associated with bentonite, granulated to a particle size of not more than 0.1 mm and dried at a temperature of 25 ° C. 2. The method of producing the sorbent according to claim 1, characterized in that ferromanganese nodules of the Gulf of Finland are used.

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