RU2462302C2 - Sorbent for cleaning gas-air mixtures, ground and waste water from petroleum and fuel hydrocarbons and method of producing said sorbent - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to environmental protection using organomineral sorbents. The sorbent is a product of modifying a mineral support with a plasticised polymer modifier. The mineral support used is natural and synthetic silicates and/or aluminosilicates. The polymer modifier used is polyethylene, polypropylene or rubber. The plasticisers used are oligomers of ethylene, aliphatic and aromatic esters of di- and tribasic acids. Components of the sorbent are in the weight ratio - mineral base: polymer: plasticiser = 100:(5-30):(1-20). The natural or synthetic silicate or aluminosilicate is treated with a solution or latex containing a polymer and a plasticiser at temperature 15-30°C, or a viscous-plastic mixture of polymer and plasticiser at temperature 100-180°C while stirring.

EFFECT: invention enables to obtain an effective sorbent with uniform distribution of the modifying layer on a natural support.

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Description

The invention relates to the field of environmental protection, in particular, to the purification of gas and air media from oil and fuel hydrocarbons using organomineral sorbents obtained by modifying the mineral base with organic polymers.

A known method of producing organomineral sorbents based on previously heat-treated zeolites by modifying them with natural macromolecular substances, and alginates polysaccharides or chitosan are used as natural macromolecular substances in an amount ensuring their content in the sorbent, respectively, wt.%: 4,5-40, 5 and 3-9, and the modification of zeolites with the indicated polysaccharides is carried out by their interaction under conditions of mechanochemical synthesis in a mill reactor of a vibrational type bo in the aquatic environment (Patent RU No. 2184607, published July 10, 2002). The resulting organomineral sorbents have a high degree of sorption of metal ions and organic dyes of various nature, however, they practically do not sorb hydrocarbons. The latter property is associated with the structural features of natural polysaccharide modifiers, which, in contrast to synthetic polymers, are characterized by a very low sorption capacity with respect to low- and non-polar organic compounds.

Also known is a method of producing an organomineral sorbent based on a clinoptilolite type zeolite and an organic polymer, including a three-step sequential treatment of a zeolite with a 33% aqueous solution of polyhexamethylene guanidine, anhydrous epichlorohydrin and, at the last stage, a 30% aqueous solution of sodium hydroxide. The duration of each stage is from 8 hours to a day, and constant or periodic mixing of the suspension is required (Patent RU No. 2050971, published December 27, 1995).

The disadvantages of this method are: high losses of polyhexamethylene guanidine due to the use of concentrated polymer solutions in the synthesis and toxicity of the used structuring agent - epichlorohydrin, which refers to substances of hazard class II.

Closest to the proposed method is a two-stage method for producing organomineral sorbents based on clinoptilolite, polyhexamethylene guanidine (or polyethyleneimine) and epichlorohydrin (Patent RU No. 2161066, published December 27, 2000), characterized by lower costs and relative ease of implementation compared to the above method (Patent RU 2050971). According to the known method, clinoptilolite is impregnated with a 10-16% aqueous solution of a mixture of an organic polymer and epichlorohydrin in their molar ratio (1-10): 1, then excess impregnation solution is removed by filtration to obtain a wet sorbent, after which the resulting sorbent is washed with a concentration of 10 alkali solution -15%, and then with water, followed by drying with hot air. Along with polyhexamethylene guanidine or polyethyleneimine, their copolymers of composition 4: 1 and 1: 4 are used as an organic polymer. Despite the decrease in the concentration of the toxic structuring agent - epichlorohydrin - in the impregnating solution, the processes of mineral modification, washing and drying of the product pose a threat to the health of staff, and also require additional measures to prevent the harmful effects of hazardous production on the environment.

Closest to the proposed composition is a sorbent consisting of a mixture of propylene stereopolymers with atactic polypropylene content from 5 to 50 wt.% (Patent RU No. 2182849, published 05.27.2002). The presence of two polypropylene (isotactic and atactic) in the structure of the hydrocarbon chain in the sorbent reduces the crystallinity of their mixture, which positively affects the sorption capacity of the sorbent in relation to hydrocarbons. The disadvantages of this composition include: the high cost of the sorbent, because it consists only of synthetic polymers and does not contain cheaper components, for example, mineral additives; technological difficulties in adjusting the particle size of the sorbent to a predetermined dispersion necessary to provide the desired permeability of the sorption layer, as well as enhancing the cohesion of polymer particles as they are saturated with hydrocarbon as a result of absorption.

The aim of the invention is the creation of an organomineral sorbent with a high sorption capacity for hydrocarbons both in dry and in wet conditions and capable of purifying gas and water environments from oil and products of its processing. Moreover, the method of producing the sorbent should be technologically simple, ensure uniform distribution of the modifying layer on the minerals, not require expensive and special equipment, and be based on the use of environmentally friendly components.

In order to achieve a technical result, an organic-mineral sorbent is proposed for the purification of gas and air media from oil and fuel hydrocarbons, which is a product of modifying a mineral carrier with plasticized polymer modifiers, which includes natural and synthetic silicates and / or aluminosilicates, the polymer modifier is a synthetic polymer, and also plasticizer - ethylene oligomers or complex aliphatic and aromatic esters of dibasic and tribasic acids, and having mineral base: polymer: plasticizer, equal in weight units of 100: 5-30: 1-20, characterized by high sorption activity with respect to hydrocarbons in the vapor phase (capacity for hexane and benzene - up to 300 μl / g) and in water phase (the values of the sorption coefficients for benzene K _d ~ 14-16). As a mineral carrier use sand, zeolites, zeolite-bearing rocks, montmorillonites, bentonites, silica gels, diatomites; polymer modifier - low molecular weight polyethylene, natural and synthetic rubbers: isoprene, chloroprene, butadiene, styrene butadiene, methyl styrene butadiene, divinyl chlorobutadiene, butyl rubber, bromobutyl rubber, chlorobutyl rubber; plasticizer - ethylene oligomers, dialkyl phthalates, alkyl aryl phthalates, triaryl phosphates, dialkyl adipates, dialkyl sebacinates.

A method for producing an organomineral sorbent by treating natural or synthetic silicate or aluminosilicate with a mixture of polymer and plasticizer in a ratio of 5-30: 1-20 in the form of latex or a solution in an organic solvent at a temperature of 15-30 ° C or with a visco-plastic mixture of a polymer and plasticizer in a ratio of 5- 30: 1-20 at a temperature of 100-180 ° C with stirring while maintaining the ratio of mineral carrier: polymer: plasticizer, equal in weight units of 100: 5-30: 1-20. In the case of processing the mineral base with a solution or latex, the organomineral sorbent is filtered off and dried at a temperature of 90-110 ° C. In the case of latex modification, the mineral carrier is pretreated with coagulants (salts of polyvalent metals). The proposed method provides a uniform distribution of all components in an organomineral sorbent. This is achieved by the simultaneous introduction of a modifier and a plasticizer in the form of a liquid mixture (latex, solution or melt) into a reactor filled with a mineral base. The proposed method gives the resulting plasticized polymer coating homogeneity, which ensures its high sorption capacity with respect to hydrocarbons, as well as reproducibility of consumer and technological properties of the sorbent. The proposed method also simplifies and reduces the cost of sorbent production technology.

The invention consists in the following:

Synthetic polymers, the molecules of which have a carbon chain structure, absorb hydrocarbons, linking them in the bulk of the polymer phase. In accordance with the absorption mechanism, the degree of binding of a hydrocarbon sorbate is determined by the rate and depth of its diffusion into the polymer phase. The diffusion process is substantially controlled by the structure of the polymer phase, first of all, by its most important indicator - the density, which is directly dependent on the energy of interaction of the polymer molecules with each other. As a result, the greater the energy of intermolecular interaction in the polymer, the greater its density and, accordingly, the lower the absorption of the hydrocarbon sorbate. In order to weaken the intermolecular bond between the polymer chains, organic plasticizers are introduced into the proposed composition, which sharply increase the sorption activity of the sorbent with respect to hydrocarbons - in the vapor phase (hexane and benzene capacity up to 300 μl / g) and in the aqueous phase (sorption coefficient K _d benzene ~ 14-16).

To reduce the cost of the sorbent and improve its filtering characteristics, cheap minerals are used as an inorganic base in the composition of the organomineral sorbent. The use of minerals does not lead to a decrease in the sorbing ability of the proposed composition, since the uniform distribution of the mineral-based polymer in the form of a film, the volume of which is almost completely accessible for the diffusion of hydrocarbon sorbate in it, in combination with the action of an organic plasticizer, allows to increase the sorption capacity due to the absence of diffusion difficulties in the interaction of the sorbent with hydrocarbon. The uniform distribution of the modifying layer on the surface of the mineral particles is achieved by the simultaneous introduction of a modifier and plasticizer into the reactor in the form of a liquid mixture (solution or melt). The thickness of the organic layer is controlled by the ratio of the amount of mineral and modifying composition introduced into the reactor. By varying the content in the proposed composition of minerals, as well as modifying and plasticizing additives, it was experimentally established that, in general, sorbents with optimal sorption and filtering characteristics are obtained when the sorbent contains a mineral base of 66.67-94.34 wt.%, Polymer 4, 72-20.00%, plasticizer 0.94-13.33%.

Example 1

100 parts by weight were placed in a metal container. dry sand, was added 10 wt.h. low molecular weight polyethylene NMPE (TU 2211-060-00203521-2002, melting point 85 ° C, crystallinity 3-16%, molecular weight 50-8000 Da). The plasticizer was ethylene oligomers with a molecular weight of less than 540 Da contained in low molecular weight polyethylene. The container was placed for 30 minutes in a heat chamber heated to 100-120 ° С, then it was thoroughly mixed and kept at the indicated temperature for another 30 minutes. The mixture was cooled and stirred until loose.

Example 2

100 parts by weight were placed in a container at 25 ° C. silica gel with a particle size of 0.2-1.0 mm, a solution of 20 parts by weight was added with stirring low molecular weight polyethylene NMPE with the characteristics shown in Example 1, 300 parts by weight hexane or petroleum ether. The plasticizer was ethylene oligomers with a molecular weight of less than 540 Da contained in low molecular weight polyethylene. The solvent was evaporated in a water bath with stirring until a thick mass was formed, then the sorbent was placed for 1 h in a heat chamber heated to 100-120 ° C to remove residual solvent. The mixture was cooled and stirred until free flowing.

Example 3

100 parts by weight were placed in a container at 25 ° C. dry sand, a solution of 20 parts by weight was added with stirring. bromobutyl rubber and 10 parts by weight dinonylphthalate at 500 parts by weight carbon tetrachloride. The mixture was stirred for 30 minutes, then filtered. The sorbent was placed for 1-2 hours in a heat chamber heated to 100-120 ° C to remove residual solvent. The mixture was cooled and stirred until free flowing.

Example 4

100 parts by weight were placed in a container at 25 ° C. dry sand, a solution of 30 parts by weight was added with stirring. chlorobutyl rubber and 20 parts by weight tricresyl phosphate at 500 parts by weight carbon tetrachloride. The mixture was stirred for 30 minutes, then filtered. The sorbent was placed for 1-2 hours in a heat chamber heated to 100-120 ° C to remove residual solvent. The mixture was cooled and stirred until free flowing.

Example 5

100 parts by weight were placed in a container at 25 ° C. silica gel with a particle size of 0.2-1.0 mm, pre-treated with a 5% aqueous solution of aluminum sulfate and dried, was added with stirring a mixture of 30 parts by weight latex DVHB-70 and 10 parts by weight tricresyl phosphate. The mixture was stirred for 30 minutes, then filtered. The sorbent was placed for 1-2 hours in a heat chamber heated to 100-120 ° C for drying. The mixture was cooled and stirred until free flowing.

Example 6

100 parts by weight were placed in a container at 25 ° C. silica gel with a particle size of 0.2-1.0 mm, a solution of 20 parts by weight was added with stirring natural rubber of the “smoked-shit” brand and 5 parts by weight dioctyl adipate in 500 parts by weight Nefras C2 80/120. The mixture was stirred for 30 minutes, then filtered. The sorbent was placed for 1-2 hours in a heat chamber heated to 100-120 ° C to remove residual solvent. The mixture was cooled and stirred until free flowing.

Claims (8)

1. Organomineral sorbent of oil and fuel hydrocarbons from gas-air and aqueous media based on natural and synthetic polymers, characterized in that it contains a plasticizer and a mineral carrier in the following ratio: mineral carrier - 100 parts by weight, polymer - (5-30) parts by weight, plasticizer - (1-20) parts by weight, where ethylene oligomers, aliphatic and aromatic esters of dibasic and tribasic acids selected from the group are used as plasticizer: dialkyl phthalates, alkylaryl phthalates, triaryl phosphates, dialkyl adipates, dialkyl adipates alkyl sebacinates. 2. The sorbent according to claim 1, characterized in that low molecular weight polyethylene and polypropylene, natural and synthetic rubbers selected from the group: isoprene, chloroprene, butadiene, butadiene-styrene, butadiene-methylstyrene, divinyl-chlorobutadiene, butyl rubber, are used as the polymer bromobutyl rubber, chlorobutyl rubber. 3. The sorbent according to claim 2, characterized in that sand, zeolites, zeolite-containing rocks, montmorillonites, bentonites, silica gels, diatomites are used as a mineral carrier. 4. The method of producing the sorbent according to claim 1 by modifying the mineral carrier with organic polymers, characterized in that a mixture of polymer with a plasticizer is applied to the mineral carrier. 5. The method according to claim 4, characterized in that the mixture of polymer with a plasticizer in the form of a solution is applied to a mineral carrier at a temperature of 15-30 ° C with stirring. 6. The method according to claim 4, characterized in that the mixture of the polymer with a plasticizer in the form of latex is applied to a mineral carrier treated with a coagulant at a temperature of 15-30 ° C with stirring. 7. The method according to claim 5 or 6, characterized in that after processing the organomineral sorbent is filtered off and dried at a temperature of 90-120 ° C. 8. The method according to claim 4, characterized in that the mixture of polymer and plasticizer in a visco-plastic state is applied to a mineral carrier at a temperature of 100-180 ° C with stirring.