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INVENTION
Russian Federation Patent RU2045574
METHOD FOR PRODUCING SOLID biosorbents FOR EXTRACTION OF METALS
Name of the inventor: Karavaiko GI .; Galician NB .; Avakian ZA .; Korenevsky AA .; Zakharov VI .; Shcherbak VV
The name of the patentee: Open Joint Stock Company "Scientific Research Institute of Plastics im.G.S.Petrova with Pilot Plant plastics Moscow"; Institute of Microbiology, Russian Academy of Sciences
Address for correspondence:
Starting date of the patent: 1992.12.29
Using biotechnology, it can be used for selective extraction of trace metals in hydrometallurgy, in electroplating industries in the processing of non-ferrous metals. SUMMARY OF THE INVENTION: immobilizing microbial biomass is carried out in a polymeric carrier, the immobilization process carried out in the copolymerization of mono- and / or acrylic or divinyl aromatic compounds in the presence of an organic solvent in a weight ratio biomass: monomer: solvent of 0.4 0.6 0.6 0.4 0.5 1.0 in the presence of a radical initiator at 80 to 90 ° C for 8 - 10 hours. as used microbial biomass or fodder yeast for beer or Asperqillus terreus VKM F2220.
DESCRIPTION OF THE INVENTION
The invention relates to biotechnology relates biosorbents synthesis, and can be used for selective extraction of trace metals in hydrometallurgy, in electroplating industries in the processing of non-ferrous metals.
Known beer yeast biomass for extracting scandium from dilute solutions (1). Brewer's yeast biomass is brewery waste production in an amount of 4 g was placed in 100 ml of a solution containing in g / l: Sc 1,85 mg / l; Al 2 O3 8,82, Fe 2 O 3, 7.33; TiO 2 0.82; SiO 2 0.2, at pH 1.0. After 1.5 h stirring contacting the biomass is separated by filtration. The recovery rate Sc 85,5% ie biomass exhibits high selectivity for scandium.
However, when using pure biomass causes serious technological difficulties associated with separation of the biomass from the solution. There is a big loss of biomass, and the biomass activity decreases after the first few cycles of sorption-desorption. Therefore, technically acceptable metal sorption solid biosorbents developed on the basis of the microbial biomass.
A method of producing biosorbents solid biomass by chemical treatment with glutaraldehyde or toluene diisocyanate, and the inclusion of a polyacrylamide, agar, alginate or silica gels. As the use of biomass and Chlorella cells streptomitsitov for uranium extraction (2) and Citrobacter Sp for the extraction of cadmium (3). These sorbents exhibit high selectivity, their use of more high-tech. However, their use in industry and unacceptable due to poor mechanical strength, and a low sorption capacity per unit volume of the sorbent, due to the high swelling known gels.
Analysis of the prior art reveals that the most similar to the proposed method for producing a solid biosorbents by immobilizing the microbial biomass in the process of copolymerization of acrylamide (4). These biosorbents recommended for the extraction of metals.
The known method is carried out as follows: A suspension of chlorella cells of streptomycetes and chilled buffer (5 g of cells per 25 ml buffer) was mixed with a mixture of acrylamide (7.23 g) and N, N'-methylenebisacrylamide (0.37 g) in chilled buffer ( 0.05 m tris-HCl). The mixture was then poured into a vessel containing the polymerization initiator (ammonium persulfate tetramethylenediamine c). Polymerization was carried out in a nitrogen atmosphere for 2 minutes, the vessel was cooled and then kept at room temperature for 1 hour. The polymerized gel was washed with water and granulated. Granulated through a nylon sieve or buffer treatment under stirring. This creates a lot of waste, which are removed by decantation.
In the result based biosorbent Chlorella extract 160 mg / g (1.33 mg eq / g) of uranium, based on streptomycetes 312 mg / g (2.6 mg + q / g). Biosorbent mechanical strength compared with the non-immobilized cell increases substantially (losses of ~ 5 cycles of 10% instead of 50%). However, the known method has a number of significant shortcomings, virtually precluding its use in the industry. Is unsatisfactory mechanical strength biosorbent. High moisture content, swelling in water and correspondingly low bulk sorption capacity biosorbent lead to low efficiency of columnar sorption processes. In addition, a significant drawback is that not all types of biomass can be immobilized by a known method. Thus, an attempt to immobilize the brewer's yeast in an acrylamide gel is not allowed to enter more than 10% is unacceptable.
The object of the present invention is to improve the sorption properties for rare metals and diffused and longer service life.
This object is achieved in that the receiving biosorbents is performed by immobilizing the microbial biomass in a polymeric carrier, wherein the immobilization is carried out during the copolymerization of mono- and / or acrylic or divinyl aromatic compounds in the presence of an organic solvent in a weight ratio biomass: monomer: solvent equal to 0, 4-0,6: 0.6-0.4: 0.5-1.0, in the presence of a radical initiator at 80-90 ° C for 8-10 hours and used as a microbial biomass or fodder yeast for beer or Aspergillus terrus VKM F-2220.
This enhances sorption capacity (volume) and dispersed on rare metals by 1.5 times and increase service life of the sorbent due to the increase of mechanical strength by 20% Thus, the capacity of scandium from dilute solutions of 1.0 mg / ml (instead of 0.15 mg / ml by the method-prototype) and molybdenum capacity 40 mg / ml instead of 8.5 mg / ml. The mechanical strength of 15 cycles of the proposed sorbent has a loss of not more than 20% of the sorbent according to the method prototype 40% high sorption properties due to a process for preparing biosorbent that enables variation of its chemical composition and physical (porous) structure. By changing the ratio within the specified range of monomer components, and biomass inert blowing agent may be prepared sorbents with the set sorption-kinetic properties. At the same time, the use of brewer's yeast makes it possible to dispose of waste from food production, negatively affecting the environment. Increased mechanical strength compared with sorbents known due to the fact that during the polymerization is formed securely crosslinked polymer matrix network structure instead of gelatinous matrix by using a polyacrylamide gel. For the same reason the proposed water capacity of the sorbent (30%) is significantly lower than the polyacrylamide sorbent (300%), that provides high volumetric sorption capacity, ie high efficiency of a column of the sorption process.
As biomass for solid biomass used biosorbents beer (Soccharougres carlsberjnsis) or fodder yeast, biomass of Aspergillus terreus VKM F-2220). yeast biomass contains acidic groups in an amount of not less than 1.5 mgekv / g.
As mono- and divinyl aromatic compounds are used (styrene, divinylbenzene) or acrylate (methyl methacrylate, glycidyl methacrylate, trietilenglikoldimetakrilat) monomers.
As the organic solvent used are aliphatic hydrocarbons C n alcohols 
4 toluene.
Reducing biosorbents biomass content lower than 0.4 leads to a significant drop in the sorption capacity, an increase of 0.6 in a loss of mechanical strength. The amount of organic solvent present in the copolymerization must not be greater than 1 (100%) by weight of the monomers, the sorbent is not destroyed. Decreasing the amount of less than 0.5 reduces the sorption-kinetic properties biosorbent.
The copolymerization is carried out in the presence of a radical initiator (benzoyl peroxide) at 80-90r for 8-10 h. The polymerization time depends on the composition of the monomer mixture and the blowing agent.
Tests conducted sorption properties:
for the diluted solutions of scandium, a complex salt composition simulating real solutions in the process of nitrate leaching red mud comprising: scandium 0.65 mg / L, alumina, 2.1 g / l, iron trioxide, 1.03 g / l titanium dioxide 0.23 g / l silica 0.04 g / l, at pH 1.0, the contacting for 1.5 hours with stirring. The ratio of the solid and liquid phase 1:50. Tests were performed in dynamic conditions in the column at a rate of transmittance of 5 / hr. The regeneration was carried out with a 5% solution of soda;
of molybdenum from solutions with a concentration of 215 mg of molybdenum / l tungsten ions in the presence of copper and at pH 2.
The contact time with stirring for 1.5 hours. The ratio of the solid and liquid phases of 1:50. Dynamic testing was carried out in a column at a rate of 5 / hr. Regeneration was performed with 10% ammonia solution.
Term sorbents service mechanical strength was evaluated by sorbents, which was evaluated by the weight loss biosorbent loaded in the column after 15 cycles of adsorption desorption operation.
A process for preparing solid biosorbents illustrated by the following examples.
Example 1. A mixture consisting of 20 g styrene, 5 g divinylbenzene and 3.2 mL (100 vol.) Of gasoline and 0.25 g of BR-1 grade benzoyl peroxide. This mixture is poured 25 g of brewer's yeast, are placed in a glass vial or a porcelain cup.
The mass is kept for 0.5 hours, then placed in an oven and the polymerization was conducted for 10 hours at 80 ° C Ready polymerizate recovered, crushed and treated with steam. Biosorbent then dried and crushed to a granular size of 0.25-2.0 mm. The properties of the adsorbent are shown in the table.
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Example 2-13 s. Same as Example 1. The ratio of the starting reagents, their nature, process conditions and properties obtained are shown in Table biosorbents where DVB divinylbenzene, TGM triethylene glikoldimetilakrilat. Sorption capacity scandium determined under static conditions.
CLAIM
1. METHOD FOR PRODUCING SOLID biosorbents EXTRACTION OF METALS, comprising immobilizing the microbial biomass in a polymeric carrier, carried out during the copolymerization of monomers flowing in the presence of a radical initiator to form the polymer, wherein the copolymerization is carried styrene and divinylbenzene monomers and / or acrylate monomers, or acrylate monomers and divinylbenzene in the presence of an organic solvent in a weight ratio biomass: monomer: solvent 0.4 0.6 0.6 0.4 0.5 1.0 in the presence of benzoyl peroxide at 80 to 90 o C for 8 to 10 hours, and microbial biomass QUALITY using brewer's yeast or feed or biomass of the strain of the fungus Aspergillus terreus VKM F-2220.
2. A method according to claim 1, characterized in that the use of acrylate monomers methyl methacrylate, glycidyl methacrylate and trietilenglikoldimetakrilat.
3. A method according to claim 1, characterized in that the solvent used is benzyl, iso-butanol or toluene.
print version
Publication date 15.03.2007gg
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