A sludge foaming agent and its preparation method and application

Abstract

The present invention belongs to the field of foaming technology, and specifically relates to a sludge foaming agent and a preparation method and application thereof. The sludge foaming agent provided by the present invention has stable foaming, and its main components are all derived from sludge, which has a wide source and will not cause secondary pollution. It also realizes the resource utilization of sludge and overcomes the disadvantage of the lack of animal and plant protein sources. In addition, the sludge foaming agent provided by the present invention is compounded with sludge protein and sludge particles by extracting alginate and polymer gel from sludge, thereby enhancing the viscoelasticity of the foam, greatly prolonging the stability time of the foam, and making the foam stability time greater than 48h.

Description

Technical Field

[0001] The invention belongs to the technical field of foaming, and in particular relates to a sludge foaming agent and a preparation method and application thereof. Background Art

[0002] The foaming agent has changed from using surfactant chemicals as the main foaming source in the early days to using biomass as the main foaming source. Compared with traditional physical foaming agents and chemical foaming agents, biomass foaming agents have 1 to 3 times higher foaming properties and 0.5 to 2 times higher stability than foaming agents of the same price. Moreover, the raw materials of biomass foaming agents are easy to obtain and environmentally friendly. Although they are more expensive, they are still recognized by the market.

[0003] According to the source of raw materials, biomass foaming agents include plant protein foaming agents and animal protein foaming agents. Using plant and animal proteins as basic foaming agents is the mainstream in the current domestic market, but it also has some shortcomings and defects. Plant protein foaming agents are difficult to promote on a large scale because of the unstable quality of raw materials, which results in unstable foaming performance of the final product and limited scope of application; animal protein foaming agents use animal keratin as raw material and are made through a series of chemical reactions. The raw material resources are limited and will cause secondary pollution. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a sludge foaming agent and a preparation method and application thereof. The sludge foaming agent provided by the present invention has stable foaming, and its main preparation raw materials are various sludges with a wide source, will not cause secondary pollution, and realizes the resource utilization of sludge.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a sludge foaming agent, comprising the following components in parts by weight:

[0007] 97.5-99.4 parts of sludge extracted protein aqueous solution, 0.5-2 parts of sludge granules, 0.01-0.2 parts of sludge extracted alginate, 0.1-0.3 parts of sludge extracted polymer gel;

[0008] The sludge extracted protein aqueous solution comprises 6 to 10 parts of sludge extracted protein and 87.5 to 93.4 parts of water.

[0009] Preferably, the sludge extracted protein is obtained by extracting sludge, and the sludge includes one or more of primary sludge, activated sludge, humic sludge, chemical sludge and secondary sludge.

[0010] Preferably, the method for preparing the aqueous solution of protein extracted from sludge comprises the following steps:

[0011] After solid-liquid separation of the sludge, the obtained precipitate is mixed with an inorganic alkali aqueous solution and leached to obtain a sludge alkaline leaching solution;

[0012] The sludge alkaline extract is neutralized to neutrality to obtain a sludge protein extracted aqueous solution.

[0013] Preferably, the concentration of the inorganic alkali aqueous solution is 0.1-1 mol / L; the ratio of the mass of the precipitate to the volume of the inorganic alkali aqueous solution is 1 kg:(5-15) L.

[0014] Preferably, the extraction temperature is 20-30° C. and the extraction time is 1-3 hours.

[0015] Preferably, the particle size of the sludge particles is 0.075-0.15 mm; the sludge particles are obtained by drying, crushing and screening one or more of primary sludge, activated sludge, humic sludge, chemical sludge, concentrated sludge and secondary sludge.

[0016] Preferably, the method for preparing alginate-like substances extracted from sludge comprises the following steps:

[0017] Dissolving the dried sludge particles in an aqueous solution of sodium salt, performing extraction and first centrifugation in sequence to obtain a supernatant;

[0018] After the pH value of the supernatant is adjusted to 1.5-3.5, a second centrifugation is performed, and the obtained precipitate is dissolved in an inorganic alkali solution and then mixed with an alcohol solution for alcohol precipitation. The obtained alcohol precipitation system is subjected to a third centrifugation to obtain sludge-extracted alginate.

[0019] Preferably, the method for preparing the sludge extracted polymer gel comprises the following steps:

[0020] After the solid-liquid separation of the activated sludge, the obtained precipitate is mixed with a sodium salt solution, the pH value of the obtained mixed solution is adjusted to 11-13, and extraction is performed to obtain a sludge polymer gel.

[0021] The present invention also provides a method for preparing the sludge foaming agent described in the above technical solution, comprising the following steps:

[0022] The sludge-extracted protein aqueous solution, sludge particles, sludge-extracted alginate and sludge-extracted polymer gel are mixed to obtain a sludge foaming agent.

[0023] The present invention also provides the use of the sludge foaming agent described in the above technical solution or the sludge foaming agent prepared by the preparation method described in the above technical solution.

[0024] The present invention provides a sludge foaming agent, comprising the following components by mass: 97.5-99.4 parts of sludge extracted protein aqueous solution, 0.5-2 parts of sludge granules, 0.01-0.2 parts of sludge extracted alginate, and 0.1-0.3 parts of sludge extracted polymer gel; the sludge extracted protein aqueous solution comprises 6-10 parts of sludge extracted protein and 87.5-93.4 parts of water. The sludge foaming agent provided by the present invention has stable foaming, and its main components are all derived from sludge, which has a wide source and will not cause secondary pollution, and realizes the resource utilization of sludge, overcoming the disadvantage of the lack of animal and plant protein sources. In addition, the sludge foaming agent provided by the present invention is compounded with sludge extracted alginate and sludge extracted polymer gel with sludge protein and sludge granules, and the viscosity of the solution before and after compounding is enhanced from 264.55cP to 1700cP, which strengthens the viscoelasticity of the foam, greatly prolongs the stability time of the foam, and makes the foam stability time>48h. DETAILED DESCRIPTION

[0025] The present invention provides a sludge foaming agent, comprising the following components in parts by weight:

[0026] 97.5-99.4 parts of sludge extracted protein aqueous solution, 0.5-2 parts of sludge granules, 0.01-0.2 parts of sludge extracted alginate, 0.1-0.3 parts of sludge extracted polymer gel;

[0027] The sludge extracted protein aqueous solution comprises 6 to 10 parts of sludge extracted protein and 87.5 to 93.4 parts of water.

[0028] Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials used, and commercially available products known to those skilled in the art may be used.

[0029] The sludge foaming agent provided by the present invention comprises an aqueous solution of 97.5 to 99.4 parts by mass of sludge extracted protein, preferably 98 to 99 parts. In the present invention, the aqueous solution of sludge extracted protein comprises 6 to 10 parts of sludge extracted protein and 87.5 to 93.4 parts of water, preferably 8 to 9 parts of sludge extracted protein and 89 to 91 parts of water. In an embodiment of the present invention, the sludge extracted protein is specifically 6 parts, 7 parts or 8 parts, and the water is specifically 90.95 parts, 91.83 parts or 93.22 parts.

[0030] In the present invention, the sludge protein aqueous solution is obtained by extracting sludge; the sludge preferably includes one or more of primary sludge, activated sludge, humic sludge, chemical sludge and secondary sludge, and more preferably primary sludge, activated sludge, humic sludge, chemical sludge or secondary sludge. When the sludge is the above-mentioned types, the present invention has no special restrictions on the ratio of different types of sludge, and any ratio can be used.

[0031] In the present invention, the method for preparing the aqueous solution of protein extracted from sludge preferably comprises the following steps:

[0032] After solid-liquid separation of the sludge, the obtained precipitate is mixed with an aqueous solution of an inorganic alkali and extracted to obtain an alkaline extract of sludge protein;

[0033] The sludge protein alkaline extract is neutralized to neutrality to obtain a sludge protein extracted aqueous solution.

[0034] The present invention separates the sludge into solid and liquid to obtain precipitation.

[0035] In the present invention, the solid-liquid separation includes centrifugation and filtration performed sequentially; the centrifugation rate is preferably 3000-8000rpm, more preferably 4000-6000rpm; the centrifugation time is preferably 5-20min, more preferably 10-15min; the present invention has no special limitation on the filtration process, and the filtration process well known in the art can be used.

[0036] After obtaining the precipitate, the present invention mixes the precipitate with an aqueous solution of an inorganic alkali, performs leaching, and obtains an alkaline leaching solution of sludge protein.

[0037] In the present invention, the inorganic base is preferably an alkali metal hydroxide, more preferably sodium hydroxide and / or potassium hydroxide, and in the embodiments, it can be specifically sodium hydroxide or potassium hydroxide; when the inorganic base is sodium hydroxide and potassium hydroxide, the present invention has no special limitation on the ratio of sodium hydroxide and potassium hydroxide, and any ratio can be used.

[0038] In the present invention, the concentration of the aqueous solution of the inorganic base is preferably 0.1-1 mol / L, more preferably 0.2-0.5 mol / L; the ratio of the mass of the precipitate to the volume of the aqueous solution of the inorganic base is preferably 1 kg:(5-15) L, more preferably 1 kg:(5-10) L; the extraction temperature is 20-30°C, more preferably 20-25°C, and the extraction time is preferably 1-3 h, more preferably 2 h.

[0039] After obtaining the sludge protein alkaline extract, the present invention preferably neutralizes the sludge protein alkaline extract to neutrality to obtain a sludge protein extracted aqueous solution.

[0040] In the present invention, the neutralization agent is preferably hydrochloric acid or sulfuric acid, more preferably sulfuric acid.

[0041] Based on 1 mass part of the sludge protein aqueous solution in the sludge foaming agent, the sludge foaming agent provided by the present invention includes 0.5 to 2 parts of sludge particles, preferably 0.6 to 1 part. In the embodiment of the present invention, the sludge particles are preferably 0.5 parts, 0.8 parts or 1 part.

[0042] In the present invention, the particle size of the sludge particles is preferably 0.075-0.15 mm, more preferably 0.075-0.1 mm; the sludge particles are preferably obtained by drying, crushing and screening one or more of primary sludge, activated sludge, humic sludge, chemical sludge, concentrated sludge and secondary sludge, more preferably primary sludge, activated sludge, humic sludge, chemical sludge, concentrated sludge or secondary sludge; the moisture content of the concentrated sludge is preferably 60-80%, more preferably 65-75%.

[0043] In the present invention, the drying temperature is preferably 80-130°C, more preferably 90-110°C, the time is preferably 40-60h, more preferably 48h; the drying method is preferably oven drying; the drying equipment is preferably an oven; the crushing equipment is preferably a crusher; the aperture of the sieve used for screening is preferably 150-300 mesh, more preferably 200 mesh.

[0044] The sludge particles in the present invention can synergize with the sludge protein extract to make them strongly adsorbed on the bubble surface, and at the same time form a three-dimensional network structure between the foam surface and the continuous phase to prevent the bubbles from agglomerating and disproportionating, thereby achieving the effect of enhancing the foam stability.

[0045] Based on 1 mass part of the sludge extracted protein aqueous solution in the sludge foaming agent, the sludge foaming agent provided by the present invention includes 0.01 to 0.2 parts of sludge extracted alginate, more preferably 0.02 to 0.05 parts. In the embodiment of the present invention, the sludge extracted alginate is specifically 0.02 parts, 0.03 parts or 0.05 parts.

[0046] In the present invention, the sludge-extracted alginate is preferably sludge-extracted sodium alginate.

[0047] In the present invention, the method for preparing alginate-like substances extracted from sludge preferably comprises the following steps:

[0048] Dissolving the dried sludge particles in an aqueous solution of sodium salt, and sequentially performing extraction and a first centrifugation to obtain a supernatant;

[0049] After the pH value of the supernatant is adjusted to 1.5-3.5, a second centrifugation is performed, and the obtained precipitate is dissolved in an inorganic alkali solution and then mixed with an alcohol solution for alcohol precipitation. The obtained alcohol precipitation system is subjected to a third centrifugation to obtain sludge-extracted alginate.

[0050] In the present invention, the method for preparing the dried sludge particles is preferably: after the solid-liquid separation of the sludge, drying, crushing and screening are carried out in sequence to obtain the dried sludge particles. In the present invention, the sludge preferably includes one or more of primary sludge, activated sludge, humic sludge, chemical sludge, concentrated sludge and secondary sludge, and more preferably primary sludge, activated sludge, humic sludge, chemical sludge, concentrated sludge or secondary sludge; when the sludge is the above-mentioned types, the present invention has no special restrictions on the ratio of different types of sludge, and any ratio can be used.

[0051] In the present invention, the solid-liquid separation preferably includes centrifugation and filtration performed sequentially; the centrifugation rate is preferably 3000-8000rpm, more preferably 5000rpm; the centrifugation time is preferably 5-20min, more preferably 10min; the present invention has no special limitation on the filtration process, and the filtration process well known in the art can be used.

[0052] After the solid-liquid separation, the present invention preferably dries the precipitate obtained by the solid-liquid separation; the drying temperature is preferably 50-80°C, more preferably 70°C; the drying time is preferably 40-60h, more preferably 48h; the drying method is preferably oven drying.

[0053] After the drying, the present invention preferably pulverizes the dried sludge; the pulverization method is preferably grinding; the present invention has no special limitation on the grinding process, and the grinding process well known in the art can be used.

[0054] After the pulverization, the present invention preferably sieves the pulverized sludge to obtain dried sludge particles; the aperture of the sieve used for the sieving is preferably 150-300 mesh, more preferably 200-250 mesh; the particle size of the dried sludge particles is preferably 0.075mm-0.15mm, more preferably 0.075-0.1mm.

[0055] In the present invention, the dried sludge particles are preferably dissolved in an aqueous solution of sodium salt for extraction.

[0056] In the present invention, the sodium salt preferably includes sodium carbonate and / or sodium bicarbonate, more preferably sodium carbonate; when the sodium salt is sodium carbonate and sodium bicarbonate, the present invention has no special limitation on the ratio of sodium carbonate and sodium bicarbonate, and any ratio is sufficient; the concentration of the aqueous solution of the sodium salt is preferably 0.1-0.3 mol / L, more preferably 0.2 mol / L; the ratio of the mass of the dried sludge particles to the volume of the aqueous solution of the sodium salt is preferably 1 g:(15-50) mL, more preferably 1 g:(20-30) mL; the extraction temperature is preferably 70-90°C, more preferably 80°C; the extraction time is preferably 1.5-2.5 h, more preferably 2 h.

[0057] After the extraction, the present invention preferably performs a first centrifugation on the mixed solution after extraction to obtain a supernatant; the rate of the first centrifugation is preferably 3000-8000 rpm, more preferably 5000 rpm; the time of the first centrifugation is preferably 5-20 min, more preferably 10 min.

[0058] After obtaining the supernatant, the present invention preferably adjusts the pH value of the supernatant to 1.5-3.5, and then performs a second centrifugation to obtain a precipitate; the pH value of the supernatant is more preferably 2-3, and most preferably 2.2; the reagent used to adjust the pH value is preferably an inorganic acid solution, and more preferably a sulfuric acid solution; the concentration of the sulfuric acid solution is preferably 0.1 mol / L; the speed of the second centrifugation is preferably 3000-8000 rpm, and more preferably 5000-7000 rpm; the time of the second centrifugation is preferably 5-20 min, and more preferably 5-10 min.

[0059] After obtaining the precipitate, the present invention preferably dissolves the precipitate in an inorganic alkali solution and then mixes it with an alcohol solution for alcohol precipitation. In the present invention, the inorganic alkali solution preferably includes sodium hydroxide solution and / or potassium hydroxide solution, more preferably sodium hydroxide solution; when the inorganic alkali solution is sodium hydroxide solution and potassium hydroxide solution, the present invention has no special restrictions on the ratio of sodium hydroxide solution and potassium hydroxide solution, and any ratio can be used; the concentration of the sodium hydroxide solution is preferably 0.4 mol / L; the alcohol solution preferably includes methanol solution and / or ethanol solution, more preferably ethanol solution; the volume concentration of the ethanol solution is preferably 80%; the volume ratio of the inorganic alkali solution to the alcohol solution is preferably 1: (1 to 3), more preferably 1: 2.

[0060] After the alcohol precipitation, the alcohol precipitation system obtained by the alcohol precipitation is subjected to a third centrifugation to obtain a precipitate. In the present invention, the rate of the third centrifugation is preferably 3000-8000 rpm, more preferably 4000-5000 rpm; the time of the third centrifugation is preferably 5-20 min, more preferably 5-10 min.

[0061] After obtaining the precipitate, the present invention preferably washes and dries the precipitate in sequence to obtain sludge-extracted alginate; the reagent used for the washing is preferably ethanol; the drying temperature is preferably 50 to 70°C, more preferably 55 to 60°C, and the drying time is preferably 10 to 30 hours, more preferably 12 to 24 hours.

[0062] The sludge-extracted alginate in the present invention is a polymer mainly composed of polysaccharides and proteins, and has highly similar structures and properties to alginate extracted from large seaweed. The present invention uses the sludge-extracted alginate as a stabilizer for the foaming agent to improve the foaming stability of the sludge-extracted protein.

[0063] Taking 1 mass part of the sludge extracted protein aqueous solution in the sludge foaming agent as the benchmark, the sludge foaming agent provided by the present invention includes 0.1 to 0.3 parts of sludge extracted polymer gel, and more preferably 0.15 to 0.25 parts. In an embodiment of the present invention, the sludge extracted polymer gel is specifically preferably 0.15 parts, 0.2 parts or 0.25 parts.

[0064] In the present invention, the method for preparing the polymer gel extracted from sludge preferably comprises the following steps:

[0065] After the solid-liquid separation of the activated sludge, the obtained precipitate is mixed with a sodium salt solution, the pH value of the obtained mixed solution is adjusted to 11-13, and extraction is performed to obtain a sludge extraction polymer gel.

[0066] In the present invention, the pH value of the mixed solution obtained by adjusting is preferably 11-13, more preferably 12; the solid-liquid separation includes centrifugation and filtration performed sequentially; the centrifugation rate is preferably 3000-8000rpm, more preferably 4000-5000rpm; the centrifugation time is preferably 5-20min, more preferably 5-10min; the present invention has no special limitation on the filtration process, and the filtration process well known in the art can be used.

[0067] In the present invention, the sodium salt solution preferably includes sodium carbonate solution and / or sodium chloride solution, more preferably sodium chloride solution; when the sodium salt solution is sodium carbonate solution and sodium chloride solution, the present invention has no special limitation on the ratio of sodium carbonate solution and sodium chloride solution, and any ratio can be used; the mass concentration of the sodium salt solution is preferably 0.9%; the volume ratio of the mixed solution obtained by mixing the precipitate and the sodium salt solution to the activated sludge is preferably 1: (1-1.5), more preferably 1: 1; the reagent used for adjusting the pH value is preferably sodium hydroxide solution; the concentration of the sodium hydroxide solution is preferably 0.4 mol / L.

[0068] In the present invention, the extraction temperature is preferably 20-30°C, more preferably 25°C; the extraction time is preferably 1-2h, more preferably 1h; the extraction is preferably carried out under stirring; the stirring speed is preferably 300-500rpm, more preferably 300-400rpm.

[0069] After the extraction, the present invention preferably further comprises: centrifuging, filtering and drying the mixed solution obtained by the extraction in sequence to obtain a sludge extracted polymer gel powder. In the present invention, the centrifugal speed is preferably 3000-8000rpm, more preferably 4000-5000rpm; the centrifugal time is preferably 5-20min, more preferably 5-10min; the filtration is preferably performed using a 0.45μm filter membrane; the drying is preferably freeze drying; the freeze drying temperature is preferably -50--30°C, more preferably -40°C; the freeze drying time is preferably 20-30h, more preferably 12-24h.

[0070] During the sludge growth process, organic and inorganic particles, microorganisms and cationic polymers are bonded together through the adsorption and bridging of extracellular polymers, thus forming a three-dimensional gel-like network structure. In sludge treatment, sludge flocculation conditioning is a very important step. The method of adding flocculants is usually adopted, the purpose of which is to promote adsorption and electrical neutralization, adhesion and bridging on the surface of sludge colloidal particles, reduce the affinity between colloidal particles, and improve the dewatering performance of sludge. The commonly used flocculant is polyacrylamide. The main components of the sludge polymer gel in the present invention are extracellular polymers and flocculants (polyacrylamide). It is precisely because of the presence of the polymer gel that the sludge can maintain structural stability. The present invention uses sludge to extract polymer gel as a stabilizer for the sludge foaming agent to improve the foaming stability of the sludge foaming agent.

[0071] The present invention also provides a method for preparing the sludge foaming agent described in the above technical solution, comprising the following steps:

[0072] The sludge-extracted protein aqueous solution, sludge particles, sludge-extracted alginate and sludge-extracted polymer gel are mixed to obtain a sludge foaming agent.

[0073] In the present invention, the mixing is preferably carried out under stirring conditions; the stirring rate is preferably 300 to 800 rpm, more preferably 400 to 500 rpm, and the time is preferably 5 to 20 min, more preferably 5 to 10 min.

[0074] In the present invention, the mixing process of the sludge extracted protein aqueous solution, sludge particles, sludge extracted alginate and sludge extracted polymer gel is preferably: adding sludge particles, sludge extracted alginate and sludge extracted polymer gel to the sludge extracted protein aqueous solution. When the water in the sludge extracted protein aqueous solution is different from the water in the sludge foaming agent by mass, the present invention preferably removes part of the water in the sludge extracted protein aqueous solution or adds part of the water to the sludge extracted protein aqueous solution.

[0075] The present invention also provides the use of the sludge foaming agent described in the above technical solution or the sludge foaming agent prepared by the preparation method described in the above technical solution in the foaming field.

[0076] The present invention has no special limitation on the application mode of the sludge foaming agent in the foaming field, and it can be selected according to actual needs.

[0077] The main components of the sludge foaming agent provided by the present invention are all derived from sludge, which realizes the resource utilization of sludge. At the same time, the sludge has a wide source, which overcomes the disadvantage of the lack of animal and plant protein sources. In addition, the sludge foaming agent provided by the present invention is compounded with sludge-extracted alginate and sludge-extracted polymer gel, sludge protein and sludge particles, which strengthens the viscoelasticity of the foam and greatly prolongs the stability time of the foam, and the foam stability time is greater than 48 hours.

[0078] Furthermore, the raw materials for preparing the sludge protein extraction in the present invention are different types of sludge, which is low in cost and suitable for large-scale application.

[0079] The high-stability sludge foaming agent provided by the present invention is suitable for controlling odor substances in various polluted sites, including: preventing the acute volatilization of odor substances during the excavation of polluted sites, ensuring the safety of construction workers, and improving the quality of the surrounding air environment; replacing the covering soil in landfills can effectively prevent the spread of odor substances and save the manpower and material resources required for covering soil. Using the solution provided by the present invention to control odor pollution sources exposed to the air can effectively prevent the spread of odor substances into the atmosphere, and the effective time is greater than 48 hours.

[0080] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0081] Example 1

[0082] The sludge foaming agent provided in this embodiment is composed of the following components in parts by weight:

[0083] 8 parts of sludge extracted protein, 0.8 parts of sludge particles (particle size 0.075 mm), 0.05 parts of sludge extracted sodium alginate, 0.2 parts of sludge extracted polymer gel, 90.95 parts of water;

[0084] The sludge particles are prepared by the following steps: taking concentrated sludge (water content 65%) and drying it in an oven at 100° C. for 48 hours, crushing it with a crusher after drying, and passing it through a 200-mesh sieve after crushing;

[0085] The sludge-extracted sodium alginate is prepared by the following steps: taking sludge and centrifuging at 5000rpm for 10min, drying the precipitate at 70°C for 48h, grinding the medium, passing through a 200-mesh sieve (0.075mm), dissolving each 1g of sludge in 20mL of a 0.2mol / L sodium carbonate solution, extracting at 80°C for 2h, centrifuging at 5000rpm for 10min after extraction, discarding the precipitate, adjusting the pH value of the supernatant to 2.2 with 0.1mol / L sulfuric acid, centrifuging at 5000rpm for 10min again, washing the precipitate with deionized water until the effluent is neutral, dissolving it in a 0.4mol / L NaOH solution, injecting twice the volume of 80% ethanol, centrifuging at 5000rpm for 10min again, washing the generated precipitate with ethanol, and drying at 60°C for 24h;

[0086] The sludge-extracted polymer gel is prepared by the following steps: taking activated sludge and centrifuging it at 5000rpm for 10 minutes, discarding the supernatant to remove suspended impurities in the sludge, adding 0.9% NaCl solution to the pretreated sludge to restore the original volume, then adding 0.4mol / LNaOH solution to adjust the pH value to 12, stirring at 25°C and 300rpm for 1h, then centrifuging again at 5000rpm for 10min, discarding the precipitate, filtering the obtained supernatant through a 0.45μm filter membrane, and freeze-drying it at -40°C for 24h to obtain sludge polymer gel powder;

[0087] The sludge was centrifuged at 5000 rpm for 10 min and then immersed in a sodium hydroxide aqueous solution (0.4 mol / L) for alkaline extraction at a temperature of 25°C and a liquid-to-solid ratio of 10:1. After extraction for 2 h, the sludge protein alkaline extract was obtained by filtering. The pH value of the alkaline solution of the sludge protein was adjusted to neutral with sulfuric acid, and then sludge particles, sludge-extracted sodium alginate, and sludge-extracted polymer gel were added in the above-mentioned mass proportions and stirred evenly at 500 rpm for 10 min to obtain a high-stability sludge foaming agent.

[0088] Example 2

[0089] The high stability sludge foaming agent provided in this embodiment includes the following components in parts by weight:

[0090] 6 parts of sludge extracted protein, 0.5 parts of sludge particles with a particle size of 0.075 mm, 0.03 parts of sludge extracted sodium alginate, 0.25 parts of sludge extracted polymer gel, and 93.22 parts of water.

[0091] The sludge was centrifuged at 5000 rpm for 15 min and then immersed in a potassium hydroxide aqueous solution (0.4 mol / L) for alkaline extraction at a temperature of 25°C and a liquid-to-solid ratio of 10:1. After extraction for 2 h, the sludge protein alkaline extract was obtained by filtering. The pH value of the alkaline solution of the sludge protein was adjusted to neutral with hydrochloric acid, and then sludge particles, sludge-extracted sodium alginate, and sludge-extracted polymer gel were added in the above-mentioned mass proportions and stirred evenly at 800 rpm for 15 min to obtain a high-stability sludge foaming agent.

[0092] Example 3

[0093] The high stability sludge foaming agent provided in this embodiment includes the following components in parts by weight:

[0094] 7 parts of sludge extracted protein, 1 part of sludge particles with a particle size of 0.075 mm, 0.02 parts of sludge extracted sodium alginate, 0.15 parts of sludge extracted polymer gel, and 91.83 parts of water.

[0095] The sludge was centrifuged at 5000 rpm for 20 min and then immersed in a sodium hydroxide aqueous solution (0.4 mol / L) for alkaline extraction at a temperature of 25°C and a liquid-to-solid ratio of 10:1. After extraction for 2 h, the sludge protein alkaline extract was obtained by filtering. The pH value of the alkaline solution of the sludge protein was adjusted to neutral with sulfuric acid, and then sludge particles, sludge-extracted sodium alginate, and sludge-extracted polymer gel were added in the above-mentioned mass proportions and stirred evenly at 500 rpm for 10 min to obtain a high-stability sludge foaming agent.

[0096] Comparative Example 1

[0097] The difference from Example 1 is that the sodium alginate extracted from sludge and the polymer gel extracted from sludge are not contained, and the rest of the contents are consistent with Example 1.

[0098] Performance Testing

[0099] (1) 50 mL of the sludge foaming agent prepared in Example 1 was stirred in a low-speed stirrer at 3000 rpm for 10 min, and the foaming volume was observed to be 200 mL. It was left to stand at room temperature of 25° C. and the half-life time was observed to be greater than 48 h.

[0100] The contaminated site in this implementation is a landfill, and its main odor is hydrogen sulfide. The concentration of hydrogen sulfide in the air 20 cm above the contaminated surface is 936 mg / m 3 The sludge foaming agent prepared in this example is foamed with a matching foam spraying device and sprayed on the surface of the contaminated soil with a spraying thickness of 10 cm. After the foam is laid, the timing sampling is started for analysis.

[0101] After the sludge foaming agent prepared in this example was covered on the hydrogen sulfide contaminated soil for 10 minutes, the concentration of hydrogen sulfide in the air 20 cm above the contaminated soil decreased from 936 mg / m 3 Reduced to 39 mg / m 3 , the removal rate reached 95.8%.

[0102] (2) 50 mL of the sludge foaming agent prepared in Example 2 was stirred in a low-speed stirrer at 3000 rpm for 10 min, and the foaming volume was observed to be 200 mL. It was left to stand at room temperature of 25° C. and the half-life time was observed to be greater than 48 h.

[0103] The contaminated site in this implementation is the old site of a pesticide factory. The main odor is dichlorodifluoromethane. The concentration of dichlorodifluoromethane in the air 20 cm above the contaminated surface is 868 mg / m 3 The high stability foaming agent prepared in this example is foamed with a matching foam spraying device and sprayed on the surface of the contaminated soil with a spraying thickness of 10 cm. After the foam is laid, timed sampling and analysis are started.

[0104] After the sludge foaming agent prepared in this example was covered on the above-mentioned difluorodichloromethane contaminated soil for 10 minutes, the concentration of difluorodichloromethane in the air 20 cm above the contaminated soil decreased from 868 mg / m 3 Reduced to 29 mg / m 3 , the removal rate reached 96.7%.

[0105] (3) 50 mL of the sludge foaming agent prepared in Example 3 was stirred in a low-speed stirrer at 3000 rpm for 10 min, and the foaming volume was observed to be 200 mL. It was left to stand at room temperature of 25° C. and the half-life time was observed to be greater than 48 h.

[0106] The contaminated site in this implementation is a sludge dumping site. The main odor is methyl mercaptan. The concentration of methyl mercaptan in the air 20 cm above the contaminated surface is 917 mg / m 3 The sludge foaming agent prepared in this example is foamed with a matching foam spraying device and sprayed on the surface of the contaminated soil with a spraying thickness of 10 cm. After the foam is laid, the timing sampling is started for analysis.

[0107] After the sludge foaming agent prepared in this example was covered on the methyl mercaptan contaminated soil for 10 minutes, the concentration of methyl mercaptan in the air 20 cm above the contaminated soil decreased from 917 mg / m 3 Reduced to 36 mg / m 3 , the removal rate reached 96.1%.

[0108] (4) The solution viscosity of the sludge foaming agent obtained in Example 1 and the sludge foaming agent obtained in Comparative Example 1 was tested.

[0109] After testing, the viscosity of the sludge foaming agent obtained in Example 1 is 1700 cP, and the viscosity of the sludge foaming agent obtained in Comparative Example 1 is 264.55 cP. It can be seen that the present invention improves the viscosity of the solution by compounding the sludge-extracted alginate and the sludge-extracted polymer gel with the sludge protein and the sludge particles, thereby enhancing the viscoelasticity of the foam and greatly prolonging the stability time of the foam, making the foam stability time greater than 48 hours.

[0110] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A sludge foaming agent, characterized in that: The method is composed of the following components in parts by weight: 97.5 to 99.4 parts of an aqueous solution of protein extracted from sludge, 0.5 to 2 parts of sludge particles, 0.01 to 0.2 parts of alginate extracted from sludge, and 0.1 to 0.3 parts of a polymer gel extracted from sludge; The sludge extracted protein aqueous solution is composed of 6 to 10 parts of sludge extracted protein and 87.5 to 93.4 parts of water; The method for preparing the aqueous solution of protein extracted from sludge comprises the following steps: after solid-liquid separation of the sludge, the obtained precipitate is mixed with an inorganic alkali aqueous solution, and leaching is performed to obtain a sludge alkaline leaching solution; neutralizing the sludge alkaline extract to neutrality to obtain a sludge protein extracted aqueous solution; The concentration of the inorganic alkali aqueous solution is 0.1-1 mol / L; the ratio of the mass of the precipitate to the volume of the inorganic alkali aqueous solution is 1 kg: (5-15) L; the leaching temperature is 20-30° C., and the leaching time is 1-3 h; The method for preparing alginate extracted from sludge comprises the following steps: dissolving dried sludge particles in an aqueous solution of sodium salt, sequentially performing extraction and first centrifugation to obtain a supernatant; After adjusting the pH value of the supernatant to 1.5-3.5, a second centrifugation is performed, and the obtained precipitate is dissolved in an inorganic alkaline solution and then mixed with an alcohol solution for alcohol precipitation, and the obtained alcohol precipitation system is subjected to a third centrifugation to obtain sludge-extracted alginate; The method for preparing the sludge-extracted polymer gel comprises the following steps: after solid-liquid separation of activated sludge, the obtained precipitate is mixed with a sodium salt solution, the pH value of the obtained mixed solution is adjusted to 11-13, and extraction is performed to obtain the sludge-extracted polymer gel.

2. The sludge foaming agent according to claim 1, characterized in that The sludge extracted protein is obtained by extracting sludge, and the sludge includes one or more of primary sludge, activated sludge, humus sludge, chemical sludge and secondary sludge.

3. The sludge foaming agent according to claim 1, characterized in that The particle size of the sludge particles is 0.075-0.15 mm; the sludge particles are obtained by drying, crushing and screening one or more of primary sludge, activated sludge, humic sludge, chemical sludge, concentrated sludge and secondary sludge.

4. The method for preparing the sludge foaming agent according to any one of claims 1 to 3, comprising the following steps: The sludge-extracted protein aqueous solution, sludge particles, sludge-extracted alginate and sludge-extracted polymer gel are mixed to obtain a sludge foaming agent.

5. Use of the sludge foaming agent according to any one of claims 1 to 3 or the sludge foaming agent prepared by the preparation method according to claim 4 in the field of foaming.