Process for the separation of biological sulphur

Abstract

The present application relates to the field of sulfur separation, and particularly relates to a biological sulfur separation method, which comprises: contacting a material containing biological sulfur with nano-magnetic enzyme. The method realizes the separation of biological sulfur by adopting nano-magnetic enzyme and magnetic flocculation, can quickly and efficiently separate biological sulfur, is simple to operate, is friendly to the environment, and can reuse enzyme preparation and magnetic flocculant, and has high biological sulfur recovery rate and high sulfur purity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sulfur separation method, in particular to a biological sulfur separation method. BACKGROUND

[0002] Biological desulfurization technology is a new technology developed in 1980s to replace conventional desulfurization technology, which has many advantages, such as no need of catalyst and oxidant, no need of chemical sludge treatment, little biological pollution, low energy consumption, high sulfur recovery, high efficiency, no odor, etc. The disadvantages are that the process is not easy to control and the conditions are harsh.

[0003] In the biological reactor, the elemental sulfur (biological sulfur) obtained by biological conversion is very different from the chemical elemental sulfur in the nature in many aspects. Lettinga et al. found that the biological sulfur obtained by microorganism conversion has a very rough and uneven surface by exploring the characteristics of the biological sulfur and observing the morphological characteristics of the biological sulfur. The protruding part on the surface of the biological sulfur is various biological macromolecular polymers attached to the surface of the biological sulfur particles, which is in sharp contrast to the chemical sulfur particles, the surface of which is very smooth, and the chemical sulfur particles have regular geometric shapes. He found that the long-chain polymers on the surface of the biological sulfur particles also have negative charges, which have a negative effect on the aggregation and precipitation of the sulfur particles. Therefore, the elemental sulfur obtained by biological conversion is in a colloidal state and is not easy to settle and aggregate, and is in a suspended state in water, which is difficult to separate from water.

[0004] At present, the commonly used separation methods of particulate matter mainly include gravity sedimentation method, centrifugal precipitation method, flocculation precipitation method, air floatation method, etc. The current research on the separation method of biological sulfur mainly focuses on the separation of biological sulfur in the sulfide removal process. The biological sulfur particles can be separated from water by using flocculation sedimentation method, but the flocculant will wrap the biological sulfur particles inside, which causes great difficulty in subsequent solvent extraction and crystallization purification. The process of "slow filter pool filtration-sand scraping-extraction-distillation" is used to realize the recovery of elemental sulfur, but the extraction is expensive, the economic cost is too high, and the toxicity is very large, so the engineering application needs to be further studied. The Shell-Paques company in the Netherlands uses air floatation method to recover biological sulfur particles, which not only has large energy consumption and high economic cost, but also the biological sulfur particles are easily oxidized in the floatation process, so it is not suitable for large-scale use. SUMMARY

[0005] The purpose of the present application is to overcome the problems existing in the prior art, and to provide a biological sulfur separation method, which realizes the separation of biological sulfur by using nano-magnetic enzyme digestion combined with magnetic flocculation, can quickly and efficiently separate biological sulfur, and has the advantages of simple operation, environmental friendliness, and reusability of enzyme preparation and magnetic flocculant, and high biological sulfur recovery rate and sulfur purity.

[0006] To achieve the above object, the present application provides a method for separating bio-sulfur, characterized in that the method comprises contacting bio-sulfur-containing material with nano-magnetic enzyme.

[0007] Through the above technical solution, the method for separating bio-sulfur can decompose macromolecular polymers attached to the surface of bio-sulfur particles with impurities into biological small molecules under the action of nano-magnetic enzyme, and utilize the biological small molecules as microbial nutrient sources, so that the negative electrically charged attachments on the surface of bio-sulfur are reduced, and the settling performance is improved. Further, in the preferred embodiment, the method further comprises using magnetic flocculants to promote the aggregation of bio-sulfur particles, forming larger composite magnetic flocs, and rapidly settling under the action of gravity and external magnetic field force to obtain separation.

[0008] The present application can quickly and efficiently separate bio-sulfur and effluent, the clear liquid can be recycled, the operation is simple, the environment is friendly, the enzyme preparation and the magnetic flocculant can be repeatedly used, the bio-sulfur recovery rate can reach above 98%, and the sulfur purity can reach above 95%.

[0009] The method for separating bio-sulfur can be used for treating material from a sulfur recovery treatment unit in a microbial desulfurization process of natural gas, biogas, coal-fired flue gas, sulfur-containing wastewater, etc., and has a wide application range. DETAILED DESCRIPTION

[0010] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The approximate values allow for variation based on experimental error, measurement techniques, and the like. Any numerical value can be converted to a range by adding or subtracting a value from the numerical value. Any range can be subdivided into a number of smaller ranges having endpoints that are the approximate values.

[0011] In the present application, the term "enzyme activity unit" refers to the amount of enzyme, which is the amount of enzyme required to produce 1 micromole of product in 1 minute under specific conditions, and is referred to as one enzyme activity unit (IU, also referred to as U).

[0012] The definition of the enzyme activity unit of protease is that 1 micromole of tyrosine is hydrolyzed in 1 minute under the condition of 37℃ and pH7.

[0013] The definition of the enzyme activity unit of cellulase is that 1 micromole of glucose is hydrolyzed in 1 minute under the condition of 25℃ and pH7.

[0014] The definition of the enzyme activity unit of lipase is that 1 μmol of fatty acid is hydrolyzed from polyvinyl olive oil emulsion in 1 minute at 25℃ and pH 7.

[0015] The present application provides a method for separating bio-sulfur, which is characterized in that the method comprises contacting a bio-sulfur-containing material with nano-magnetic enzyme.

[0016] In the present application, the bio-sulfur-containing material contains pure bio-sulfur (elemental sulfur) and bio-sulfur with impurities, the content of the pure bio-sulfur is 40-70% by weight, the surface of the bio-sulfur with impurities is rough and uneven, the protruding part of the surface is a bio-macromolecular polymer attached to the surface of the bio-sulfur particle, and the long-chain polymer on the surface of the bio-sulfur with impurities usually has a negative charge.

[0017] Preferably, the content of the bio-sulfur with impurities in the bio-sulfur-containing material is 0.1-1 g / L, and more preferably 0.2-0.5 g / L. More preferably, the particle size of the bio-sulfur with impurities is 1-10 μm.

[0018] Preferably, the surface of the bio-sulfur with impurities has a negative charge. More preferably, the zeta potential of the single bio-sulfur particle with impurities is -30 mV to -50 mV.

[0019] In the present application, the bio-sulfur-containing material can be a bio-desulfurization bacteria catalyzed HS - ion into elemental sulfur process, which can be obtained from a sulfur recovery treatment unit in a microbial desulfurization process of natural gas, biogas, coal-fired flue gas, sulfur-containing wastewater, etc. Generally, the surface of the sulfur particles in the material is attached with bio-polymers such as polysaccharides, proteins and lipids, etc. The content of each of the polysaccharides, proteins and lipids can be 0.5-2% by weight, 2-5% by weight, 0.1-1% by weight, respectively.

[0020] Preferably, the contacting method is that the bio-sulfur-containing material continuously flows through the nano-magnetic enzyme, and the amount of the bio-sulfur with impurities flowing through each gram of the nano-magnetic enzyme per hour is 1-30 g.

[0021] Preferably, the nano-magnetic enzyme comprises magnetic particles and enzyme preparations fixed on the magnetic particles, and the magnetic particles are chitosan-coated ferroferric oxide magnetic nanoparticles. The particle size of the magnetic particles can be 100-500 nm.

[0022] In the present application, the nano-magnetic enzyme is an enzyme preparation capable of degrading bio-polymers fixed on a magnetic ferroferric oxide chitosan nanoparticle.

[0023] In the present application, the preparation method of the nano-magnetic enzyme can comprise the following steps: firstly, preparing the ferroferric oxide magnetic nanoparticles with a magnetic core by the coprecipitation method; secondly, coating the chitosan on the surface of the ferroferric oxide magnetic nanoparticles by the electrostatic adsorption method to form the magnetic ferroferric oxide chitosan immobilized enzyme carrier (i.e. the chitosan-coated ferroferric oxide); and thirdly, using a crosslinking agent (such as glutaraldehyde) to fix the free enzyme preparation on the magnetic ferroferric oxide chitosan immobilized enzyme carrier. The coating amount of the chitosan can be 0.03-0.08 mg per milligram of ferroferric oxide, and the loading amount of the enzyme preparation can be 10-200 U. The particle size of the ferroferric oxide can be 100-500 nm. The amount of the crosslinking agent (such as glutaraldehyde) can be 15-35 g per gram of the chitosan-coated ferroferric oxide magnetic nanoparticles.

[0024] In the detailed description of the present application, the specific preparation method of the nano-magnetic enzyme comprises the following steps:

[0025] (1) Firstly, the ferroferric oxide magnetic nanoparticles with a magnetic core are prepared by the coprecipitation method: the chitosan solution is added into the ultrasonically dispersed Fe3O4 magnetic fluid, stirred at room temperature for 3-5 h, ultrasonically dispersed for 5-15 min, and washed by the magnetic separation method for 4-5 times to obtain the chitosan-coated ferroferric oxide magnetic nanoparticles after modification.

[0026] Preferably, the content of chitosan in the chitosan solution is 0.5-2 wt%, and more preferably, the solvent of the chitosan solution is 0.5-2 wt% acetic acid aqueous solution.

[0027] (2) The chitosan-coated ferroferric oxide magnetic nanoparticles are dispersed in the glutaraldehyde aqueous solution, placed on a constant-temperature shaker at 20-30 °C for oscillation for 3-6 h, then separated by a magnet, and repeatedly washed with deionized water to wash away the unreacted glutaraldehyde; then the enzyme preparation solution is added, placed on a constant-temperature shaker at 20-30 °C for oscillation for 2-4 h, and the supernatant is filtered, and repeatedly washed with distilled water until no enzyme activity is detected in the washing liquid.

[0028] Preferably, the amount of the glutaraldehyde is 15-35 g per gram of the chitosan-coated ferroferric oxide magnetic nanoparticles, and more preferably, the concentration of the glutaraldehyde aqueous solution is 2-6 wt%.

[0029] Further preferably, the loading amount of the enzyme preparation can be 10-200 U per milligram of ferroferric oxide. More preferably, the concentration of the enzyme preparation in the enzyme preparation solution is 5-20 mg / mL.

[0030] In the present application, the enzyme preparation on the nanometer magnetic enzyme can be various common enzymes for separating bio-sulfur, for example, the enzyme preparation on the nanometer magnetic enzyme is at least one of protease, cellulase and lipase; preferably protease, cellulase and lipase.

[0031] Preferably, the ratio between the protease, cellulase and lipase activity units per unit carrier mass of the nanometer magnetic enzyme is 1-150:0.2-10:1.

[0032] More preferably, the protease activity per unit carrier mass of the nanometer magnetic enzyme is 10-150 U / mg.

[0033] More preferably, the cellulase activity per unit carrier mass of the nanometer magnetic enzyme is 2-30 U / mg.

[0034] More preferably, the lipase activity per unit carrier mass of the nanometer magnetic enzyme is 1-10 U / mg.

[0035] More preferably, the protease is alkaline protease, preferably Bacillus licheniformis protease.

[0036] More preferably, the lipase is glycerol ester hydrolase.

[0037] In the present application, the contact between the bio-sulfur-containing material and the nanometer magnetic enzyme is carried out in a solid-liquid magnetic fluidized bed. Under the action of an applied magnetic field, the nanometer magnetic enzyme presents a regular fluidized state, greatly improving the enzyme catalytic reaction speed. At the same time, the nanometer magnetic enzyme is locked in the magnetic field area, and the bio-sulfur-containing material can be continuously contacted with the nanometer magnetic enzyme and quickly separated, which can effectively improve the degradation efficiency of the bio-polymer on the surface of sulfur. Therefore, preferably, the contact is carried out in a solid-liquid magnetic fluidized bed.

[0038] In order to obtain better separation effect, more preferably, the contact is carried out in 2-5 solid-liquid magnetic fluidized beds in series.

[0039] Preferably, the flow rate of the material in the solid-liquid magnetic fluidized bed is in the range of 0.003-0.005 m / s, and the magnetic field strength is 0.025-0.045 T. More preferably, the amount of nanometer magnetic enzyme in each solid-liquid magnetic fluidized bed is 10-50 mg.

[0040] In the present application, the temperature of the contact can be room temperature, such as 20-40℃.

[0041] In the present application, the aggregation of biological sulfur particles is promoted by adding magnetic flocculants to form larger composite magnetic flocs, which can be carried out in a flocculation tank. Then, magnetic separation is carried out under the action of an external magnetic field, which is beneficial to realize rapid flocculation and separation of biological sulfur and further improve the purity of the obtained biological sulfur. The magnetic separation can be carried out in a weak magnetic field magnetic separator. Therefore, preferably, the method further comprises: carrying out solid-liquid separation after mixing the contact product with the magnetic flocculants.

[0042] More preferably, the magnetic flocculants comprise four-iron oxide magnetic powder.

[0043] More preferably, the particle size of the magnetic flocculants ranges from 1 to 10 μm.

[0044] More preferably, the amount of the magnetic flocculants added is 100-500 mg per liter of the contact product.

[0045] Preferably, the mixing conditions are as follows: pH value is 5-7, and time is 10-30 min. Since the four-iron oxide magnetic powder is positively charged and the biological sulfur is negatively charged, the two are electrostatically attracted to form flocs.

[0046] Preferably, the solid-liquid separation is carried out by magnetic separation, preferably, the mixed product is put into a magnetic separator for magnetic separation.

[0047] Preferably, the magnetic field strength of the magnetic separation is 0.08-0.3 T.

[0048] Preferably, the method further comprises: removing the magnetic particles in the solid phase obtained by solid-liquid separation.

[0049] In the present application, the product after flocculation treatment is subjected to magnetic separation to obtain a solid phase and a liquid phase. The solid phase contains biological sulfur, and the liquid phase contains rich biological small molecules, which are nutrient substances required for microbial growth, and can be pumped into a biological desulfurization unit for recycling.

[0050] Preferably, the magnetic particles in the solid phase are removed by putting the solid phase into a magnetic recovery device for recovery.

[0051] In the present application, the biological sulfur composite magnetic flocs after magnetic separation are put into a magnetic recovery device to recover the magnetic particles, and the remaining part is pure biological sulfur. The magnetic particles can be reused after activation and regeneration.

[0052] In the present application, the activation and regeneration of the magnetic particles can be carried out by ultrasonic treatment.

[0053] In the present application, the unit "T (Tesla)" used is a magnetic field strength unit, which is the ratio of the magnetic field acting on a current-carrying conductor perpendicular to the direction of the magnetic field to the product of the current intensity and the length of the conductor, and is called the magnitude of the magnetic induction at the place where the current-carrying straight conductor is located, with the unit of Tesla.

[0054] The present application will be described in detail below through examples.

[0055] The temperature control of the magnetic fluidized bed in each embodiment is 25℃;

[0056] The source of the biological sulfur material is the product of a microbial hydrogen sulfide removal device;

[0057] The protease is an alkaline protease purchased from Henan Wanbang Industry Co., Ltd., with an enzyme activity of 200,000 U / g;

[0058] The cellulase is a cellulase purchased from Zhejiang Yinao Biological Technology Co., Ltd., with an enzyme activity of 50,000 U / g;

[0059] The lipase is a lipase purchased from Shandong Longkete Enzyme Preparation Co., Ltd., with an enzyme activity of 100,000 U / g;

[0060] The determination method of the biological sulfur content adopts the sulfite method, which utilizes the principle that elemental sulfur and sulfite in water are converted into measurable thiosulfate at high pH value, and determines the content of thiosulfate in the reaction solution by ion chromatography to indirectly reflect the content of biological sulfur. The determination steps are described in the literature (Reduction of produced elementary sulfur in denitrifying sulfide removal process. Environmental biotechnology, 2011, 90: 1129-1136.). The biological sulfur content before and after flocculation of the effluent containing biological sulfur is determined, and the recovery rate of biological sulfur can be calculated according to the determination results. The biological sulfur with impurities will affect the flocculation of biological sulfur, and further affect the recovery rate of biological sulfur.

[0061]

[0062] In the formula, a0 represents the total amount of biological sulfur in the effluent containing biological sulfur, with the unit of mg / L; and a1 represents the amount of biological sulfur contained in the liquid phase after flocculation and magnetic separation treatment, with the unit of mg / L.

[0063] The purity of elemental sulfur (i.e. the purity of bio-sulfur) was determined by high performance liquid chromatography. 0.01 g of recovered elemental sulfur was accurately weighed and dissolved in 100 mL of tetrachloroethylene. After dissolution, the solution was filtered through a 0.22 μm organic membrane. The chromatographic conditions were as follows: chromatographic column: Agilent, SB-C18 (4.6 mm x 250 mm), mobile phase: methanol: water = 95:5, flow rate: 1 mL / min, injection volume: 10 uL, UV detector, detection wavelength: 263 nm; column temperature: 35 °C. The retention time of the chromatographic peak was used for qualitative determination, and the peak area was used for quantitative determination of the results by external standard method.

[0064] Enzyme activity determination: The enzyme activity was determined according to the definition of the enzyme activity unit described above.

[0065]

[0066] In the formula, A is the measured mass of the decomposition product, mg; T is the enzyme hydrolysis time, min; B is the enzyme amount, mg / g; n is the dilution multiple; C is the molar mass of the substrate, g / mol; and 60 is the time conversion coefficient, s / min.

[0067]

[0068] In the formula, the enzyme activity of the enzyme solution is 100% (initial enzyme activity). The enzyme activity determined under different conditions is compared with the initial enzyme activity, and is expressed as relative enzyme activity.

[0069] Preparation Example

[0070] Fe 2+ (FeSO4·7H2O) and Fe 3+ (FeCl4·6H2O) were co-precipitated with 25% (volume fraction) NH3·6H2O at 60 °C to obtain magnetic Fe3O4particles. 0.8 g of chitosan was added to a 1 wt% aqueous acetic acid solution to prepare a 1% chitosan solution. After complete dissolution, 1000 mg of ultrasonically dispersed Fe3O4magnetic fluid was added to 250 mL of the chitosan solution. The mixture was stirred at room temperature for 4 h, ultrasonically dispersed for 10 min, and washed by magnetic separation for 4 times to obtain chitosan-coated Fe3O4magnetic nanoparticles. The coating amount of chitosan per milligram of Fe3O4was 0.05 mg.

[0071] The 500 mg of chitosan-coated ferroferric oxide magnetic nanoparticles were dispersed in 300 mL of a 4 wt% glutaraldehyde aqueous solution, and placed in a constant-temperature shaker at 25°C for 4 h, and then separated by a magnet. The unreacted glutaraldehyde was repeatedly washed away with deionized water. Then, 50 mL of a 5-20 mg / mL enzyme preparation solution (see the examples for the specific amount of each enzyme preparation) was added, and placed in a constant-temperature shaker at 25°C for 3 h. The supernatant was filtered, and repeatedly washed with distilled water until no enzyme activity was detected in the washing liquid.

[0072] Example 1

[0073] The effluent containing biological sulfur with an impurity content of 0.2 g / L was introduced into a 3-stage magnetic fluidized bed. The material flow rate was 0.004 m / s, and the magnetic field strength was 0.031 T. The amount of nanomagnetic enzyme added to each single magnetic fluidized bed was 40 mg, and the proteinase activity, cellulase activity, and lipase activity of the nanomagnetic enzyme per unit carrier mass were 100 U / mg, 20 U / mg, and 8 U / mg, respectively (the amounts of the proteinase preparation, cellulase, and lipase used in the preparation example were 250 mg, 200 mg, and 40 mg, respectively). The material was treated at a rate of 0.226 g of biological sulfur with impurities per hour. The hydrolyzed effluent containing biological sulfur was introduced into a flocculation tank, and the pH was adjusted to 6.5. Then, 200 mg / L of magnetic flocculant (Fe3O4 magnetic powder with a particle size of 1-10 μm) was added, and the mixture was uniformly stirred for flocculation. After 15 min, the treated material was transported to a weak magnetic field magnetic separator with a magnetic field strength of 0.25 T. After magnetic separation, the liquid phase was removed, and the solid phase was collected. The collected solid phase was transported to a magnetic recovery device, and the magnetic particles were recovered. The remaining part was the biological sulfur.

[0074] When the nanomagnetic enzyme was continuously used for 72 h, the relative enzyme activity of the magnetic enzyme particles decreased to 80%. Meanwhile, the magnetic flocculant was recycled for 5 times, the recovery rate of biological sulfur reached 99.5%, and the purity of biological sulfur reached 98.7%.

[0075] Example 2

[0076] The effluent of the biological sulfur content of 0.2 g / L with impurities to be treated containing biological sulfur material is passed into a 5-stage magnetic fluidized bed in series, the material flow rate is 0.004 m / s, and the magnetic field intensity is 0.031 T. The addition amount of nano-magnetic enzyme in each single magnetic fluidized bed is 20 mg, the protease activity, cellulase activity and lipase enzyme activity of the nano-magnetic enzyme per unit carrier mass are 80 U / mg, 10 U / mg and 3 U / mg respectively (the preparation example uses 200 mg of protease preparation, 100 mg of cellulase and 15 mg of lipase), and 0.226 g of biological sulfur with impurities is treated per hour. The effluent containing biological sulfur after hydrolysis is flowed into a flocculation tank, after adjusting the pH to 6.5, 200 mg / L of magnetic flocculants (Fe3O4 magnetic powder with a particle size of 1-10 μm) is added, and the mixture is uniformly stirred for flocculation reaction. After 15 min, the treated material is transported to a weak magnetic field magnetic separator with a magnetic field intensity of 0.25 T, after magnetic separation, the liquid phase is removed, and the solid phase is collected. The collected solid phase is transported to a magnetic recovery device, the magnetic particles are recovered, and the remaining part is biological sulfur.

[0077] When the nano-magnetic enzyme is continuously used for 72 h, the relative enzyme activity of the magnetic enzyme particles decreases to 85%, at the same time, the magnetic flocculants are recycled for 5 times, the biological sulfur recovery rate reaches 99.1%, and the biological sulfur purity reaches 97.6%.

[0078] Example 3

[0079] The effluent of the biological sulfur content of 0.5 g / L with impurities to be treated containing biological sulfur material is passed into a 3-stage magnetic fluidized bed in series, the material flow rate is 0.004 m / s, and the magnetic field intensity is 0.031 T. The addition amount of nano-magnetic enzyme in each single magnetic fluidized bed is 40 mg, the protease activity, cellulase activity and lipase enzyme activity of the nano-magnetic enzyme per unit carrier mass are 100 U / mg, 20 U / mg and 8 U / mg respectively (the preparation example uses 250 mg of protease preparation, 200 mg of cellulase and 40 mg of lipase), and 0.565 g of biological sulfur with impurities is treated per hour. The effluent containing biological sulfur after hydrolysis is flowed into a flocculation tank, after adjusting the pH to 6.5, 300 mg / L of magnetic flocculants (Fe3O4 magnetic powder with a particle size of 1-10 μm) is added, and the mixture is uniformly stirred for flocculation reaction. After 15 min, the treated material is transported to a weak magnetic field magnetic separator with a magnetic field intensity of 0.25 T, after magnetic separation, the liquid phase is removed, and the solid phase is collected. The collected solid phase is transported to a magnetic recovery device, the magnetic particles are recovered, and the remaining part is biological sulfur.

[0080] When the nanometer magnetic enzyme is continuously used for 72 h, the relative enzyme activity of the magnetic enzyme particles decreases to 83%, while the magnetic flocculant is recycled for 5 times, the biological sulfur recovery rate reaches 99.2%, and the biological sulfur purity reaches 98.1%.

[0081] Example 4

[0082] The effluent containing biological sulfur with an impurity content of 0.5 g / L to be treated is introduced into a 5-stage magnetic fluidized bed in series, the material flow rate is 0.004 m / s, and the magnetic field strength is 0.031 T. The addition amount of nanometer magnetic enzyme in each single magnetic fluidized bed is 20 mg, the proteinase activity, cellulase activity, and lipase activity of the nanometer magnetic enzyme per unit carrier mass are 80 U / mg, 10 U / mg, and 3 U / mg respectively (the preparation amount of proteinase in the preparation example is 200 mg, the cellulase amount is 100 mg, and the lipase amount is 15 mg), and 0.565 g of biological sulfur with impurities is treated per hour. The effluent containing biological sulfur after hydrolysis is introduced into a flocculation tank, after adjusting the pH to 6.5, 300 mg / L of magnetic flocculant (Fe3O4 magnetic powder, particle size is 1-10 μm) is added, the mixture is uniformly stirred and subjected to flocculation reaction. After 15 min, the treated material is transported to a weak magnetic field magnetic separator with a magnetic field strength of 0.25 T, after magnetic separation, the liquid phase is discharged, and the solid phase is collected. The collected solid phase is transported to a magnetic recovery device, the magnetic particles are recovered, and the remaining part is biological sulfur.

[0083] When the nanometer magnetic enzyme is continuously used for 72 h, the relative enzyme activity of the magnetic enzyme particles decreases to 78%, while the magnetic flocculant is recycled for 5 times, the biological sulfur recovery rate reaches 98.9%, and the biological sulfur purity reaches 97.8%.

[0084] Example 5

[0085] The effluent of the material containing biological sulfur with 1 g / L of biological sulfur with impurities was introduced into a 2-stage magnetic fluidized bed in series, the material flow rate was 0.004 m / s, and the magnetic field intensity was 0.031 T. The addition amount of nano-magnetic enzyme in each single magnetic fluidized bed was 50 mg, the protease activity, cellulase activity and lipase activity of the nano-magnetic enzyme per unit carrier mass were 150 U / mg, 30 U / mg and 10 U / mg respectively (the amount of protease preparation used in the preparation example was 375 mg, the amount of cellulase used was 300 mg, and the amount of lipase used was 50 mg), and 1.13 g of biological sulfur with impurities was treated per hour. The effluent containing biological sulfur after hydrolysis was introduced into a flocculation tank, after adjusting the pH to 6.5, 500 mg / L of magnetic flocculants (Fe3O4 magnetic powder with a particle size of 1-10 μm) was added, and the mixture was stirred uniformly for flocculation reaction. After 15 min, the treated material was transported to a weak magnetic field magnetic separator with a magnetic field intensity of 0.25 T, after magnetic separation, the liquid phase was removed, and the solid phase was collected. The collected solid phase was transported to a magnetic recovery device, the magnetic particles were recovered, and the remaining part was biological sulfur.

[0086] When the nano-magnetic enzyme was continuously used for 72 h, the relative enzyme activity of the magnetic enzyme particles decreased to 81%, at the same time, the magnetic flocculants were recycled for 5 times, the recovery rate of biological sulfur reached 98.5%, and the purity of biological sulfur reached 96.7%.

[0087] Example 6

[0088] The effluent of the material containing biological sulfur with 1 g / L of biological sulfur with impurities was introduced into a 2-stage magnetic fluidized bed in series, the material flow rate was 0.004 m / s, and the magnetic field intensity was 0.031 T. The addition amount of nano-magnetic enzyme in each single magnetic fluidized bed was 50 mg, the protease activity, cellulase activity and lipase activity of the nano-magnetic enzyme per unit carrier mass were 150 U / mg, 30 U / mg and 10 U / mg respectively (the amount of protease preparation used in the preparation example was 375 mg, the amount of cellulase used was 300 mg, and the amount of lipase used was 50 mg), and 1.13 g of biological sulfur with impurities was treated per hour. The effluent containing biological sulfur after hydrolysis was introduced into a flocculation tank, after adjusting the pH to 6.5, 500 mg / L of magnetic flocculants (Fe3O4 magnetic powder with a particle size of 1-10 μm) was added, and the mixture was stirred uniformly for flocculation reaction. After 15 min, the treated material was transported to a weak magnetic field magnetic separator with a magnetic field intensity of 0.25 T, after magnetic separation, the liquid phase was removed, and the solid phase was collected. The collected solid phase was transported to a magnetic recovery device, the magnetic particles were recovered, and the remaining part was biological sulfur.

[0089] When the nano-magnetic enzyme was continuously used for 72 h, the relative enzyme activity of the magnetic enzyme particles decreased to 77%, at the same time, the magnetic flocculants were recycled for 5 times, the recovery rate of biological sulfur reached 98.1%, and the purity of biological sulfur reached 95.8%.

[0090] Example 7

[0091] The method of Example 1 was followed, except that the material flow rate was changed to 0.011 m / s and the magnetic field strength was changed to 0.085 T.

[0092] When the nano-magnetic enzyme was continuously used for 72 h, the relative enzyme activity of the magnetic enzyme particles decreased to 70%, and the magnetic flocculant was recycled for 5 times, the biological sulfur recovery rate reached 95.3%, and the biological sulfur purity reached 92.5%.

[0093] Example 8

[0094] The method of Example 1 was followed, except that the amount of the magnetic flocculant added was changed to 50 mg / L.

[0095] When the nano-magnetic enzyme was continuously used for 72 h, the relative enzyme activity of the magnetic enzyme particles decreased to 78%, and the magnetic flocculant was recycled for 5 times, the biological sulfur recovery rate reached 88.7%, and the biological sulfur purity reached 97.6%.

[0096] Comparative Example 1

[0097] The biological sulfur-containing effluent with a biological sulfur content of 0.2 g / L was introduced into the pretreatment tank, and 40 mg / L of the composite free enzyme preparation was added, wherein the protease activity, cellulase activity, and lipase enzyme activity were 100 U / mg, 20 U / mg, and 8 U / mg, respectively (the amount of the protease preparation used in the preparation example was 250 mg, the amount of the cellulase used was 200 mg, and the amount of the lipase used was 40 mg). 0.226 g of the impurity-containing biological sulfur was treated per hour. The biological sulfur-containing effluent after hydrolysis was introduced into the flocculation tank, 200 mg / L of the polyaluminum chloride flocculant was added, and the mixture was introduced into the sedimentation tank for separation. The biological sulfur recovery rate reached 81.2%, and the sulfur purity reached 84.7%.

[0098] When the composite free enzyme preparation was continuously used for 72 h, the relative enzyme activity decreased to 50% due to enzyme loss and other reasons. The polyaluminum chloride flocculant cannot be recycled and needs to be continuously added.

[0099] Comparative Example 2

[0100] The effluent containing biosulphur with 0.2 g / L of impure biosulphur is introduced into a pretreatment tank, and 40 mg / L of a complex free enzyme preparation is added in the pretreatment tank, wherein the protease activity, cellulase activity and lipase enzyme activity are 100 U / mg, 20 U / mg and 8 U / mg respectively (the preparation amount of the protease is 250 mg, the cellulase is 200 mg and the lipase is 40 mg in the preparation example), and 0.226 g of impure biosulphur is treated per hour. The hydrolyzed effluent containing biosulphur is introduced into a flocculation tank, and after the pH is adjusted to 6.5, 200 mg / L of a magnetic flocculant (magnetic powder with a particle size of 1-10 μm) is added, and the mixture is uniformly stirred and flocculated. After 15 min, the treated material is transported to a weak magnetic field magnetic separator with a magnetic field strength of 0.25 T, and after magnetic separation, the liquid phase is removed, and the solid phase is collected. The collected solid phase is transported to a magnetic recovery device, and the magnetic particles are recovered, and the remaining part is biosulphur.

[0101] When the complex free enzyme preparation is continuously used for 72 h, the relative enzyme activity decreases to 52% due to enzyme loss and other reasons. The magnetic flocculant is recycled for 5 times, the biosulphur recovery rate reaches 98.3%, and the biosulphur purity reaches 85.1%.

[0102] From the implementation effect of the comparative example, it can be seen that under the same conditions, the nano magnetic enzyme is in a steady state in the magnetic fluidized bed, is not easy to lose, and fully contacts with the material to perform an enzymatic reaction, so that the sulphur purity reaches more than 95%, which is increased by 12.2% than the complex free enzyme preparation. The magnetic flocculant is used in the flocculation process, the flocculation effect is good, the magnetic flocculant can be recycled for multiple times, and after magnetic separation, the purity of the biosulphur is not affected, and the sulphur recovery rate reaches more than 98%, which is increased by 20.7% than the conventional flocculant.

[0103] The preferred embodiments of the application are described in detail above, but the application is not limited thereto. Within the technical concept of the application, various simple modifications can be made to the technical solutions of the application, including that various technical features are combined in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the application, and all fall within the protection scope of the application.

Claims

1. A method for the separation of biological sulphur, characterized in that, The method comprises: contacting a material containing biological sulfur with nano-magnetic enzyme; The nano-magnetic enzyme comprises magnetic particles and enzyme preparation fixed on the magnetic particles, and the magnetic particles are chitosan-coated ferroferric oxide magnetic nanoparticles; The enzyme preparation on the nano-magnetic enzyme is at least one of protease, cellulase and lipase; The contacting is performed in a solid-liquid magnetic fluidized bed.

2. The separation method of claim 1, wherein, The content of the biological sulfur with impurities in the material containing biological sulfur is 0.1-1 g / L.

3. The separation method according to claim 1 or 2, wherein, The content of the biological sulfur with impurities in the material containing biological sulfur is 0.2-0.5 g / L.

4. The separation method of claim 2, wherein, The particle size of the biological sulfur with impurities is 1-10 μm.

5. The separation method of claim 2, wherein, The biological sulfur with impurities has a negative charge on the surface.

6. The separation method of claim 2, wherein, The zeta potential of a single biological sulfur particle with impurities is -30 mV to -50 mV.

7. The separation method according to claim 1 or 2, wherein, The contacting is performed by continuously flowing the material containing biological sulfur through the nano-magnetic enzyme, and the amount of the biological sulfur with impurities flowing through per gram of the nano-magnetic enzyme per hour is 1-30 g.

8. The separation method of claim 7, wherein, The enzyme preparation on the nano-magnetic enzyme is protease, cellulase and lipase.

9. The separation method of claim 8, wherein, The ratio between the units of protease, cellulase and lipase per unit of carrier mass of the nano-magnetic enzyme is 1-150:0.2-10:1; And / or, the protease activity per unit of carrier mass of the nano-magnetic enzyme is 10-150 U / mg; And / or, the cellulase activity per unit of carrier mass of the nano-magnetic enzyme is 2-30 U / mg; And / or, the lipase activity per unit of carrier mass of the nano-magnetic enzyme is 1-10 U / mg; And / or, the protease is alkaline protease; And / or, the lipase is glyceride hydrolase.

10. The separation method of claim 9, wherein, The protease is Bacillus licheniformis protease.

11. The separation method according to claim 1 or 2, wherein, The contacting is performed in 2-5 solid-liquid magnetic fluidized beds in series.

12. The separation method of claim 1, wherein, The flow rate of the material in the solid-liquid magnetic fluidized bed ranges from 0.003 m / s to 0.005 m / s, the magnetic field strength ranges from 0.025 T to 0.045 T, and the amount of the nano-magnetic enzyme in each solid-liquid magnetic fluidized bed ranges from 10 mg to 50 mg.

13. The separation method of claim 1 or 2, wherein, The method further comprises: mixing the contacting product with a magnetic flocculating agent and then performing solid-liquid separation.

14. The separation method of claim 13, wherein, The magnetic flocculating agent comprises ferroferric oxide magnetic powder; And / or, the particle size of the magnetic flocculating agent ranges from 1 μm to 10 μm; And / or, the amount of the magnetic flocculating agent relative to each liter of the contacting product ranges from 100 mg to 500 mg; And / or, the mixing condition is that the pH value ranges from 5 to 7 and the time ranges from 10 min to 30 min; And / or, the solid-liquid separation is performed by magnetic separation.

15. The separation method of claim 14, wherein, The magnetic field strength of the magnetic separation ranges from 0.08 T to 0.3 T.

16. The separation method of claim 13, wherein, The method further comprises: removing the magnetic particles in the solid phase obtained by the solid-liquid separation.

17. The separation method of claim 16, wherein, The removal is performed by placing the solid phase into a magnetic recovery device for recovery.

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