A high-efficiency domestic sewage treatment flocculant and its preparation method and application

Abstract

This invention provides a high-efficiency flocculant for treating domestic sewage, its preparation method, and its application. Specifically, it includes component A and component B. Component A is an inorganic polymer obtained using loess as the silicon, aluminum, and iron source through an alkali fusion, acid leaching, and polymerization process. In the flocculant, it functions as an adhesive agglomerator, adsorbent charge neutralization, adsorption bridging, and sweeping trap. Component B is an organic polymer obtained by modifying apple pomace. In the flocculant, it functions as an emulsifier and gelling agent, and also provides a carrier for component A, improving its stability. This invention uses natural loess and apple pomace as raw materials to prepare an environmentally friendly inorganic-organic polymeric composite flocculant. The raw materials are abundant, the preparation process is simple, the product is safe and environmentally friendly, has a wide range of applications, broad usage conditions, low dosage, fast settling speed, and good flocculation effect. The chemical composition of the sediment is close to the natural background value, and it can be recycled or biodegraded without causing secondary pollution.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a high-efficiency flocculant for treating domestic wastewater, its preparation method, and its application. Background Technology

[0002] Most domestic sewage contains nutrients such as nitrogen and phosphorus, as well as pollutants such as pathogens and organic matter. Some domestic sewage also contains heavy metals. If it is discharged directly into rivers and lakes without treatment, it will seriously pollute the ecological environment and harm human health.

[0003] Currently, the main methods for treating domestic sewage include biological treatment, activated carbon treatment, flocculation sedimentation, membrane separation, electrolysis, and wet catalytic oxidation. Among these, the water after biological treatment tends to have high color, while activated carbon deep treatment, membrane separation, electrolysis, and wet catalytic oxidation are costly, significantly limiting their practical application. In comparison, flocculation sedimentation is economical, efficient, and easy to operate. The core of flocculation sedimentation lies in the selection of flocculants. Currently, the most commonly used flocculants are polyaluminum chloride (PAC) and polyacrylamide (PAM). However, PAC has drawbacks such as weak bridging ability, slow settling speed, loose and fragile flocs, turbid effluent, and high residual aluminum content. PAM, on the other hand, has a long dissolution time at low temperatures, and excessive dosage can lead to viscous water, reduced fluidity, and blockage of dosing pipes. Furthermore, PAM has poor quality stability. Using PAC and PAM alone makes it difficult to simultaneously settle organic and inorganic matter in sewage, resulting in poor flocculation and secondary pollution.

[0004] While exploring solutions for the resource utilization of loess, the inventors developed a coagulant and its application in water-based paint wastewater (CN113461126A). Using loess as a raw material, they prepared Fenton's reagent, polyaluminum ferric sulfate, and porous structural materials, and then compounded them with modified chitosan to obtain the coagulant. However, the aforementioned solution suffers from numerous problems, including complex loess modification processes, high coagulant preparation costs, poor stability, and unsatisfactory flocculation effects on domestic sewage.

[0005] Apple pomace is a waste product from apple processing, accounting for approximately 25% of the apple's weight. Currently, there are no effective utilization methods or technologies for apple pomace, and it is generally dumped into farmland, causing numerous problems: Firstly, it undergoes uncontrolled fermentation and has a chemical oxygen demand (COD) of 250-300 g / kg, and the large quantity of apple pomace also requires a significant amount of biological oxygen demand (BOD) during natural biodegradation. Secondly, apple pomace contains a large amount of water and is prone to fermentation; improper disposal will cause serious pollution to the air and groundwater. Therefore, the safe and effective treatment of apple pomace and the prevention of environmental pollution has become a widespread problem that needs to be addressed.

[0006] Therefore, inventing a safe, environmentally friendly flocculant with good flocculation effect and low production cost is a key problem that urgently needs to be solved in the field of domestic sewage treatment. Summary of the Invention

[0007] The purpose of this invention is to provide a highly efficient flocculant for treating domestic sewage. It is made solely from loess and apple pomace, through processes such as modification, polymerization, compounding, and maturation, resulting in an inorganic-organic polymeric composite flocculant. This flocculant is non-toxic and harmless, effectively settling both organic and inorganic matter in sewage simultaneously and in a short time, exhibiting excellent flocculation performance. Only a small amount of flocculant is needed to achieve superior sewage treatment results, demonstrating significant advantages in removing turbidity, color, BOD5, COD, and fecal coliforms from water bodies. Furthermore, the flocs are readily biodegradable, preventing secondary pollution and effectively solving the problems existing in current technologies.

[0008] To achieve the above objectives, the present invention provides a high-efficiency flocculant for treating domestic sewage, comprising component A and component B;

[0009] Component A is an inorganic polymer obtained by using loess as the silicon, aluminum, and iron source alone, through alkali fusion, acid leaching, and polymerization processes; it plays a role in the flocculant by binding and agglomeration, adsorption and charge neutralization, adsorption bridging, and sweeping and trapping.

[0010] Component B is an organic polymer obtained by modifying apple pomace; it plays an emulsifying and gelling role in the flocculant, and also provides a carrier for component A, thereby improving the stability of component A.

[0011] Components A and B are compounded, matured, dried, ground, and sieved to form the flocculant.

[0012] In a preferred embodiment, the ratio of component A to component B by weight is (23~28):10.

[0013] In a preferred embodiment, the preparation method of component A includes the following steps:

[0014] S1. Disperse loess in pure water and allow it to settle naturally. Remove the upper suspension and the bottom fine sand particles and impurities. Take the middle loess slurry, centrifuge, dry, crush and sieve it to obtain loess powder.

[0015] S2. After uniformly mixing loess powder with Na2CO3, the mixture is calcined, ground, acid-leached, diluted with water, and then filtered to obtain filtrate I and filter residue.

[0016] S3. The filter residue is alkali-leached and filtered. The resulting filtrate II is acidified and polymerized, then mixed with filtrate I, alkalized and aged to obtain component A.

[0017] In a preferred embodiment, in step S1, the loess is clean loess with a moisture content of less than 5%.

[0018] In a preferred embodiment, in step S1, the ratio of loess to pure water by weight is 1:(3.0~4.0).

[0019] In a preferred embodiment, in step S1, the natural settling time is 5.0~7.0 h.

[0020] In a preferred embodiment, in step S1, the drying can be carried out using conventional equipment and conditions known to those skilled in the art to remove moisture from the loess slurry. Preferably, the drying conditions are drying at 80~100℃ for 2.0~6.0 hours.

[0021] In a preferred embodiment, in step S1, the sieving is done through a 100-mesh sieve, which makes the obtained loess powder fine and facilitates subsequent modification.

[0022] In a preferred embodiment, in step S2, the ratio of loess powder to Na2CO3 by weight is (18~22):(3~7).

[0023] In a preferred embodiment, in step S2, the calcination conditions are: calcination in a muffle furnace at 700~850 °C for 2.0~2.5 h.

[0024] In a preferred embodiment, in step S2, the grinding can be carried out using conventional methods known to those skilled in the art. Preferably, the grinding method is to grind the material through a 100-mesh sieve after cooling it to room temperature.

[0025] In a preferred embodiment, in step S2, the acid leaching conditions are as follows: 5.0~7.0 mol / L hydrochloric acid and loess powder are mixed in a weight ratio of (4.0~5.0):1, and then stirred and leached in a water bath for 1.5~3.0 h; wherein the water bath temperature is 80~90 ℃ and the stirring speed is 200~400 r / min;

[0026] More preferably, the acid leaching conditions are as follows: 6.0 mol / L hydrochloric acid and loess powder are mixed in a weight ratio of (4.0~5.0):1, and then the mixture is stirred and leached in a water bath at 80~90 ℃ at 300 r / min for 2.0~2.5 h.

[0027] In a preferred embodiment, in step S2, the ratio of dilution water to loess powder by weight is (12.0~15.0):1.

[0028] In a preferred embodiment, in step S3, the alkaline leaching conditions are as follows: 5.0~7.0 mol / L NaOH solution is mixed with the filter residue and then stirred and leached in a water bath for 1.0~2.5 h; wherein the ratio of NaOH solution to loess powder by weight is (2.0~2.5):1, the water bath temperature is 60~80 ℃, and the stirring speed is 200~400 r / min;

[0029] More preferably, the alkaline leaching conditions are as follows: after mixing 6.0 mol / L NaOH solution with the filter residue, the mixture is stirred and leached in a water bath at 300 r / min for 1.5 to 2.0 h at 60 to 80 ℃.

[0030] In a preferred embodiment, in step S3, the acidification conditions are as follows: 1.0 mol / L hydrochloric acid solution is added to filtrate II to adjust the pH to 1.8~2.2.

[0031] In a preferred embodiment, in step S3, the polymerization conditions are: stirring polymerization at room temperature for 2.0~2.5 h, followed by static activation for 2.0~3.0 h; wherein the stirring speed is 200~400 r / min, preferably 300 r / min.

[0032] In a preferred embodiment, in step S3, the alkalization conditions are as follows: in a water bath environment, 0.30 mol / L NaOH solution is slowly added dropwise over 0.5 h to adjust the pH of the system to 5.8-6.2, and stirring is continued for 0.5-1.0 h to prevent precipitation; wherein the water bath temperature is 50-60 ℃ and the stirring speed is 200-400 r / min; preferably, NaOH solution is added to adjust the pH of the system to 6.0, and the stirring speed is 300 r / min.

[0033] In a preferred embodiment, in step S3, the aging conditions are: static aging at room temperature for 12.0~18.0 h.

[0034] In this invention, through the above-described process design and the setting of suitable treatment conditions, silicon dioxide, aluminum oxide, and iron oxide in loess can be fully transformed into inorganic polymers such as polyaluminum iron silicate, polysilicic acid, polyaluminum, and polyferric silicate, forming a composite inorganic flocculant. This eliminates the need for additional iron or aluminum sources, thus reducing the use of chemical additives.

[0035] In a preferred embodiment, the preparation method of component B includes the following steps:

[0036] After crushing and sieving apple pomace, washing with warm water, acid soaking, washing with ethanol, drying, grinding and sieving, component B is obtained.

[0037] In a preferred embodiment, the apple pomace is prepared by washing fresh apples, slicing them, juicing them, and then air-drying or drying them before crushing them through a 100-mesh sieve.

[0038] In a preferred embodiment, the ratio of apple pomace to loess powder by weight is 1:2.

[0039] In a preferred embodiment, the warm water washing conditions in the preparation method of component B are as follows: washing with pure water at 40~60℃ 2~3 times, with the ratio of water to apple pomace by weight being 5:1 each time.

[0040] In a preferred embodiment, the acid leaching conditions for preparing component B are as follows: 5.0-7.0 mol / L hydrochloric acid and apple pomace are mixed in a weight ratio of 5:1, the pH of the system is adjusted to 1.5-2.0, and the mixture is stirred in a water bath for 2.0-3.0 h; wherein the water bath temperature is 90-100 ℃ and the stirring speed is 200-400 r / min.

[0041] More preferably, the acid leaching conditions are as follows: 6.0 mol / L hydrochloric acid and apple pomace are mixed in a ratio of 5:1 by weight, the pH of the system is adjusted to 1.5~2.0, and the mixture is stirred at 300 r / min for 2.0~3.0 h in a water bath at 90~100 ℃.

[0042] In a preferred embodiment, in the preparation method of component B, the ethanol washing involves repeatedly washing with 80-95% ethanol by volume until the filtrate is neutral; preferably, the ratio of ethanol used to apple pomace by weight is 2:1 for each washing.

[0043] In a preferred embodiment, in the preparation method of component B, the drying can be carried out using conventional equipment and conditions known to those skilled in the art. Preferably, the drying conditions are: drying at 40~60°C for 2.0~6.0 hours.

[0044] In a preferred embodiment, in the preparation method of component B, the grinding can be carried out using conventional methods known to those skilled in the art, preferably, the material is passed through a 100-mesh sieve after grinding.

[0045] In this invention, apple pomace is first washed with warm water to remove surface impurities. Then, through hydrochloric acid extraction and ethanol precipitation, high-molecular polymers such as pectin from the apple pomace are extracted to the surface, increasing the contact area with pollutants and improving the flocculation effect. When combined with modified loess with a porous morphology, it synergistically increases the flocculation capacity for both inorganic and organic pollutants. The resulting flocculant has high ionicity, is easily soluble in water, and exhibits good hydrolytic stability, possessing both flocculation and disinfection properties. It shows excellent removal effects on turbidity, color, BOD5, and COD in domestic sewage.

[0046] Another objective of this invention is to provide a method for preparing a high-efficiency flocculant for treating domestic sewage. The overall preparation method is simple, has less dependence on equipment and energy consumption, and is particularly suitable for large-scale industrial production.

[0047] To achieve the above objectives, the present invention provides a method for preparing a high-efficiency domestic sewage treatment flocculant, wherein component A and component B are mixed, the pH of the system is adjusted to 3.5-4.5 with hydrochloric acid or NaOH solution, heated and stirred, allowed to stand for aging, dried and ground to obtain the flocculant.

[0048] In a preferred embodiment, the concentration of the hydrochloric acid or NaOH solution is 1.0 mol / L.

[0049] In a preferred embodiment, the pH of the adjustment system is 4.0.

[0050] In a preferred embodiment, the heating and stirring conditions are: stirring at 200-400 r / min for 2.5-3.5 h at 70-80 °C.

[0051] In a preferred embodiment, the settling and ripening time is 24.0~36.0 h.

[0052] In a preferred embodiment, the drying can be carried out using conventional equipment and conditions known to those skilled in the art. Preferably, the drying conditions are: drying at 40~60°C for 2.0~6.0 hours.

[0053] In a preferred embodiment, the grinding can be carried out using conventional methods known to those skilled in the art, and preferably, the material is passed through a 150-mesh sieve after grinding.

[0054] Another objective of this invention is to provide an application of the aforementioned high-efficiency flocculant for domestic sewage treatment in the field of domestic sewage treatment. This invention uses loess as a silicon, aluminum, and iron source to prepare inorganic polymers through modification; and uses apple pomace as a biopolymer material source to prepare natural organic polymers through modification; the inorganic polymers and natural organic polymers are then compounded and matured to obtain a flocculant for treating domestic sewage. The preparation process is safe and environmentally friendly, and the resulting flocculant combines the advantages of coagulation aid, adsorption, rapid sedimentation, good floc stability, and easy biodegradability. It is simple and easy to use, with high flocculation efficiency and low cost.

[0055] To achieve the above objectives, the present invention provides a method for applying the aforementioned high-efficiency domestic sewage treatment flocculant in the field of domestic sewage treatment, comprising the following steps:

[0056] In domestic sewage with a pH range of 4.0 to 10.0, the flocculant described is added at a rate of 36.0 to 45.0 g per cubic meter of sewage. After stirring, settling, and filtering at room temperature, the water quality can meet the Class V standard requirements of the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0057] In a preferred embodiment, the stirring speed is 100~200 r / min and the stirring time is 0.1~0.5h.

[0058] In a preferred embodiment, the settling time is 2.0 to 12.0 hours.

[0059] In a preferred embodiment, the filtered residue can be recycled or biodegraded. Specifically, because the raw materials used to prepare the flocculant are non-toxic, harmless, and easily biodegradable natural loess and apple pomace, the resulting flocculent residue can be used to produce biogas and biogas fertilizer, or, under normal temperature and pressure, the flocculent residue can be transformed into harmless substances and return to nature through natural biodegradation within 1 to 6 months.

[0060] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0061] (1) The main components of the high-efficiency domestic sewage treatment flocculant provided by this invention include: inorganic polymers such as polyaluminum ferric silicate, polysilicic acid, aluminum salts, and iron salts, and natural organic polymers containing functional groups such as carboxylic acids, polyphenols, and amino acids. This flocculant combines the good bonding, aggregation, coagulation aid, adsorption, and bridging effects of polyaluminum ferric silicate and polysilicic acid. The aluminum salt flocculant has large flocs and good decolorization performance, while the iron salt flocculant has dense flocs and fast settling speed. The natural organic polymer has strong adsorption and bridging effects, stable flocs, and easy biodegradability. The composite flocculant prepared by compounding the above-mentioned inorganic polymers and natural organic polymers can play a synergistic role, and can specifically adsorb and flocculate various components (including heavy metal ions) in domestic sewage, effectively enhancing flocculation and versatility.

[0062] (2) This invention innovates the modification method of loess, making the modification process simpler, the utilization rate of effective components of loess higher, the prepared inorganic polymer components richer, the removal of more types of pollutants, and the flocculation effect better. Moreover, it does not require the addition of aluminum and iron sources. With appropriate modification methods and compounding with modified apple pomace, it achieves excellent flocculation effect, simplifies the process formula, and reduces production costs.

[0063] (3) The present invention improves the modification method of apple pomace by replacing formaldehyde-hydrochloric acid with hydrochloric acid, reducing secondary pollution, adding ethanol precipitation process, avoiding the loss of effective components in apple pomace, broadening the types of pollutants removed, and significantly improving the flocculation effect.

[0064] (4) The raw materials of this invention are natural, environmentally friendly, abundant, and inexpensive. The product preparation process is simple, the production cost is low, and it is easy to industrialize. The product is easy to use, has a wide range of applications, broad application conditions, low dosage, and good flocculation effect. The sludge can be recycled or biodegraded. It can not only effectively utilize idle loess and waste apple pomace resources, but also effectively reduce the amount of other chemical additives used, while enhancing the biodegradability of the sludge. The chemical composition of the sludge is close to the natural background value, reducing the secondary pollution of the environment by the flocculant. In particular, it has significant advantages in removing turbidity, color, BOD5, COD and fecal coliforms from domestic sewage, achieving a flocculation effect of 1+1>2. Attached Figure Description

[0065] These and / or other aspects and advantages of the present invention will become clearer and more readily understood from the following detailed description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0066] Figure 1 This is an SEM image of the flocculant prepared in Example 1 of the present invention. Detailed Implementation

[0067] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0068] This invention provides a highly efficient flocculant for treating domestic sewage, its preparation method, and its application, solving the problems of poor flocculant stability, difficulty in simultaneously settling organic and inorganic matter in sewage, high flocculant cost, and complex preparation process in the prior art when treating domestic sewage.

[0069] The technical solution of this application will be described in detail below through specific embodiments:

[0070] Unless otherwise specified, the technical means used in this invention are conventional means well known to those skilled in the art. All raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. Unless otherwise specified, all reagents used in this invention are of analytical grade.

[0071] In this invention, the weight parts can be weight units known in the art such as µg, mg, g, kg, or multiples thereof, such as 1 / 10, 1 / 100, 10, 100 times, etc.

[0072] Example 1

[0073] A high-efficiency flocculant for treating domestic sewage is prepared by the following steps:

[0074] (1) Disperse 20.0 parts of clean loess with a moisture content of less than 5% in 70 parts of pure water by weight. After natural settling for 5.0 h, remove the upper suspension and the bottom fine sand particles and other impurities. Take the middle loess slurry, centrifuge it, dry it at 100 ℃, grind it through a 100-mesh sieve, and obtain loess powder.

[0075] (2) Take 20 parts of the above loess powder and mix it evenly with 5.0 parts of Na2CO3. Then, calcine it in a muffle furnace at 850 ℃ for 2.0 h. After cooling to room temperature, grind it through a 100-mesh sieve and add it to 100 parts of 6.0 mol / L hydrochloric acid. Stir it in an 80 ℃ water bath at 300 r / min for 2.5 h. Dilute it with 250 parts of water and filter it to obtain filtrate I and filter residue. Extract the filter residue with 50 parts of 6.0 mol / L NaOH solution at 70 ℃ with stirring at 300 r / min for 2.0 h. Filter it. Adjust the pH of the filtrate to 2.0 with 1.0 mol / L hydrochloric acid. Stir it at 300 r / min at room temperature for 2.0 h. Let it stand for 2.5 h to activate it. Then add it to filtrate I and place it in a 50 ℃ water bath. Slowly add 0.30 mol / L NaOH solution dropwise over 0.5 h until the pH of the system is 6.0. Stir at r / min for 1.0 h to prevent precipitation, and let stand at room temperature for 15.0 h to obtain component A.

[0076] (3) 10.0 parts by weight of dried apple pomace were crushed and passed through a 100-mesh sieve. Each time, it was washed 2-3 times with 50 parts of pure water at 50 ℃. Then, it was added to 50 parts of 6.0 mol / L hydrochloric acid and the pH was adjusted to 1.5. The mixture was stirred at 300 r / min for 2.5 h in a 95 ℃ water bath. Each time, it was washed repeatedly with 20 parts of 80% ethanol until the filtrate was neutral. Then, it was dried at 50 ℃, ground, and passed through a 100-mesh sieve to obtain component B.

[0077] (4) Add 10.0 parts by weight of component B to 25.0 parts by weight of component A, adjust the pH to 4.0 with 1.0 mol / L hydrochloric acid or NaOH solution, stir at 300 r / min for 3.0 h at 70 ℃, let stand for 24.0 h, dry at 50 ℃, grind through a 150 mesh sieve to obtain an orange-yellow flocculant, the microstructure of which is as follows: Figure 1 As shown in the figure, the modified loess and modified apple pomace have a good combination effect, and the resulting flocculant exhibits a rich and multi-branched network aggregate morphology.

[0078] Example 2

[0079] A high-efficiency flocculant for treating domestic sewage is prepared by the following steps:

[0080] (1) Disperse 21.0 parts of clean loess with a moisture content of less than 5% in 75 parts of pure water by weight. After natural settling for 6.0 h, remove the upper suspension and the bottom fine sand particles and other impurities. Take the middle loess slurry, centrifuge it, dry it at 100 ℃, grind it through a 100-mesh sieve, and obtain loess powder.

[0081] (2) Take 21.0 parts of the above loess powder and 5.1 parts of Na2CO3, mix them evenly, and calcine them in a muffle furnace at 800 ℃ for 2.5 h. After cooling to room temperature, grind them through a 100-mesh sieve, and then add them to 90 parts of 6.0 mol / L hydrochloric acid. Stir at 300 r / min for 2.0 h in an 85 ℃ water bath. Dilute with 280 parts of water and filter to obtain filtrate I and filter residue. Extract the filter residue with 45 parts of 6.0 mol / L NaOH solution at 80 ℃ with stirring at 300 r / min for 2.0 h, filter, adjust the pH of the filtrate to 2.0 with 1.0 mol / L hydrochloric acid, stir at 300 r / min for 2.2 h at room temperature, let it stand for 2.0 h, add it to filtrate I and place it in a 55 ℃ water bath. Slowly add 0.30 mol / L NaOH solution dropwise over 0.5 h until the pH of the system is 6.0, and then stir at 300 r / min for 2 h. Stir at r / min for 1.0 h to prevent precipitation, and let stand at room temperature for 18.0 h to obtain component A.

[0082] (3) 10.5 parts by weight of dried apple pomace were crushed and passed through a 100-mesh sieve. Each time, it was washed 2-3 times with 50 parts of pure water at 50 ℃. Then, it was added to 50 parts of 6.0 mol / L hydrochloric acid and the pH was adjusted to 1.8. The mixture was stirred at 300 r / min for 2.0 h in a 100 ℃ water bath. Each time, it was washed repeatedly with 20 parts of 85% ethanol until the filtrate was neutral. Then, it was dried at 50 ℃, ground, and passed through a 100-mesh sieve to obtain component B.

[0083] (4) Add 10.0 parts by weight of component B to 25.0 parts by weight of component A, adjust the pH to 4.0 with 1.0 mol / L hydrochloric acid or NaOH solution, stir at 300 r / min for 3.0 h at 70 ℃, let stand for 36.0 h, dry at 60 ℃, grind through a 150 mesh sieve to obtain an orange-yellow flocculant.

[0084] Example 3

[0085] A high-efficiency flocculant for treating domestic sewage is prepared by the following steps:

[0086] (1) Disperse 19.0 parts of clean loess with a moisture content of less than 5% in 60 parts of pure water by weight. After natural settling for 5.5 h, remove the upper suspension and the bottom fine sand particles and other impurities. Take the middle loess slurry, centrifuge it, dry it at 100 ℃, grind it through a 100-mesh sieve, and obtain loess powder.

[0087] (2) Take 19.0 parts of the above loess powder and 4.9 parts of Na2CO3, mix them evenly, and calcine them in a muffle furnace at 700 ℃ for 2.4 h. After cooling to room temperature, grind them through a 100-mesh sieve, and then add them to 90 parts of 6.0 mol / L hydrochloric acid. Stir at 300 r / min for 2.5 h in a 90 ℃ water bath. Dilute with 260 parts of water and filter to obtain filtrate I and filter residue. Extract the filter residue with 40 parts of 6.0 mol / L NaOH solution at 80 ℃ with stirring at 300 r / min for 1.5 h, filter, adjust the pH of the filtrate to 2.0 with 1.0 mol / L hydrochloric acid, stir at 300 r / min for 2.2 h at room temperature, let it stand for 2.0 h, add it to filtrate I and place it in a 55 ℃ water bath. Slowly add 0.30 mol / L NaOH solution dropwise over 0.5 h until the pH of the system is 6.0, and then stir at 300 r / min. Stir at r / min for 1.0 h to prevent precipitation, and let stand at room temperature for 15.0 h to obtain component A.

[0088] (3) 11.0 parts by weight of dried apple pomace were crushed and passed through a 100-mesh sieve. Each time, it was washed 2-3 times with 55 parts of pure water at 50 ℃. Then, it was added to 50 parts of 6.0 mol / L hydrochloric acid and the pH was adjusted to 2.0. The mixture was stirred at 300 r / min for 3.0 h in a 98 ℃ water bath. Each time, it was washed repeatedly with 22 parts of 95% ethanol until the filtrate was neutral. The mixture was then dried at 50 ℃, ground, and passed through a 100-mesh sieve to obtain component B.

[0089] (4) Add 10.0 parts by weight of component B to 25.0 parts by weight of component A, adjust the pH to 4.0 with 1.0 mol / L hydrochloric acid or NaOH solution, stir at 300 r / min for 3.0 h at 80 ℃, let stand for 30.0 h, dry at 60 ℃, grind through a 150 mesh sieve to obtain orange-yellow flocculant.

[0090] Example 4

[0091] A high-efficiency flocculant for treating domestic sewage is prepared by the following steps:

[0092] (1) Disperse 20.0 parts of clean loess with a moisture content of less than 5% in 80 parts of pure water by weight. After natural settling for 5.5 h, remove the upper suspension and the bottom fine sand particles and other impurities. Take the middle loess slurry, centrifuge it, dry it at 100 ℃, grind it through a 100-mesh sieve, and obtain loess powder.

[0093] (2) Take 20.0 parts of the above loess powder and 4.9 parts of Na2CO3 and mix them evenly. Then, calcine them in a muffle furnace at 750 ℃ ​​for 2.4 h. After cooling to room temperature, grind them through a 100-mesh sieve and add them to 100 parts of 6.0 mol / L hydrochloric acid. Stir at 300 r / min for 2.0 h in an 88 ℃ water bath. Dilute with 280 parts of water and filter to obtain filtrate I and filter residue. Extract the filter residue with 40 parts of 6.0 mol / L NaOH solution at 65 ℃ with stirring at 300 r / min for 1.8 h. Filter the residue. Adjust the pH of the filtrate to 2.0 with 1.0 mol / L hydrochloric acid. Stir at 300 r / min for 2.2 h at room temperature. Let it stand for 3.0 h to activate. Then add it to filtrate I and place it in a 55 ℃ water bath. Slowly add 0.30 mol / L hydrochloric acid over 0.5 h. The system was prepared with NaOH solution until the pH reached 6.0, and stirred at 300 r / min for 1.0 h to prevent precipitation. The mixture was then allowed to stand at room temperature for 13.0 h to obtain component A.

[0094] (3) 10.0 parts by weight of dried apple pomace were crushed and passed through a 100-mesh sieve. Each time, it was washed 2-3 times with 50 parts of pure water at 50 ℃. Then, it was added to 50 parts of 6.0 mol / L hydrochloric acid and the pH was adjusted to 1.6. The mixture was stirred at 300 r / min for 2.8 h in a 90 ℃ water bath. Each time, it was washed repeatedly with 20 parts of 85% ethanol until the filtrate was neutral. Then, it was dried at 50 ℃, ground, and passed through a 100-mesh sieve to obtain component B.

[0095] (4) Add 10.0 parts by weight of component B to 25.0 parts by weight of component A, adjust the pH to 4.0 with 1.0 mol / L hydrochloric acid or NaOH solution, stir at 300 r / min for 3.0 h at 70 ℃, let stand and mature for 32.0 h, dry at 60 ℃, grind through a 150 mesh sieve to obtain an orange-yellow flocculant.

[0096] Example 5

[0097] A high-efficiency flocculant for treating domestic sewage is prepared by the following steps:

[0098] (1) Disperse 20.0 parts of clean loess with a moisture content of less than 5% in 75 parts of pure water by weight. After natural settling for 6.5 h, remove the upper suspension and the bottom fine sand particles and other impurities. Take the middle loess slurry, centrifuge it, dry it at 100 ℃, grind it through a 100-mesh sieve, and obtain loess powder.

[0099] (2) Take 20.0 parts of the above loess powder and 5.0 parts of Na2CO3 and mix them evenly. Then, calcine them in a muffle furnace at 800 ℃ for 2.5 h. After cooling to room temperature, grind them through a 100-mesh sieve and add them to 100 parts of 6.0 mol / L hydrochloric acid. Stir at 300 r / min for 2.0 h in a 90 ℃ water bath. Dilute with 260 parts of water and filter to obtain filtrate I and filter residue. Extract the filter residue with 48 parts of 6.0 mol / L NaOH solution at 60 ℃ with stirring at 300 r / min for 2.0 h. Filter the residue. Adjust the pH of the filtrate to 2.0 with 1.0 mol / L hydrochloric acid. Stir at 300 r / min for 1.8 h at room temperature and let it stand for 2.8 h to activate. Then add it to filtrate I and place it in a 55 ℃ water bath. Slowly add 0.30 mol / L hydrochloric acid over 0.5 h. The system was prepared with NaOH solution until the pH reached 6.0, and stirred at 300 r / min for 1.0 h to prevent precipitation. The mixture was then allowed to stand at room temperature for 16.0 h to obtain component A.

[0100] (3) 10.0 parts by weight of dried apple pomace were crushed and passed through a 100-mesh sieve. Each time, it was washed 2-3 times with 50 parts of pure water at 50 ℃. Then, it was added to 50 parts of 6.0 mol / L hydrochloric acid and the pH was adjusted to 1.8. The mixture was stirred at 300 r / min for 2.8 h in a 92 ℃ water bath. Each time, it was washed repeatedly with 20 parts of 86% ethanol until the filtrate was neutral. Then, it was dried at 50 ℃, ground, and passed through a 100-mesh sieve to obtain component B.

[0101] (4) Add 10.0 parts by weight of component B to 25.0 parts by weight of component A, adjust the pH to 4.0 with 1.0 mol / L hydrochloric acid or NaOH solution, stir at 300 r / min for 3.0 h at 80 ℃, let stand for 30.0 h, dry at 60 ℃, grind through a 150 mesh sieve to obtain orange-yellow flocculant.

[0102] Comparative Example 1

[0103] A high-efficiency flocculant for treating domestic sewage is prepared by the following steps:

[0104] (1) Disperse 20.0 parts of clean loess with a moisture content of less than 5% in 70 parts of pure water by weight. After natural settling for 5.0 h, remove the upper suspension and the bottom fine sand particles and other impurities. Take the middle loess slurry, centrifuge it, dry it at 100 ℃, grind it through a 100-mesh sieve, and obtain loess powder.

[0105] (2) Take 20 parts of the above loess powder and mix it evenly with 5.0 parts of Na2CO3. Then, calcine it in a muffle furnace at 850 ℃ for 2.0 h. After cooling to room temperature, grind it through a 100-mesh sieve and add it to 100 parts of 6.0 mol / L hydrochloric acid. Stir it in an 80 ℃ water bath at 300 r / min for 2.5 h. Dilute it with 250 parts of water and filter it to obtain filtrate I and filter residue. Extract the filter residue with 50 parts of 6.0 mol / L NaOH solution at 70 ℃ with stirring at 300 r / min for 2.0 h. Filter it. Adjust the pH of the filtrate to 2.0 with 1.0 mol / L hydrochloric acid. Stir it at 300 r / min at room temperature for 2.0 h. Let it stand for 2.5 h to activate it. Then add it to filtrate I and place it in a 50 ℃ water bath. Slowly add 0.30 mol / L NaOH solution dropwise over 0.5 h until the pH of the system is 6.0. Stir at r / min for 1.0 h to prevent precipitation, and let stand at room temperature for 15.0 h to obtain component A.

[0106] (3) Adjust component A to pH 4.0 with 1.0 mol / L hydrochloric acid or NaOH solution, stir at 300 r / min for 3.0 h at 70 ℃, let stand for 24.0 h, dry at 50 ℃, grind through a 150 mesh sieve to obtain flocculant.

[0107] Comparative Example 2

[0108] A high-efficiency flocculant for treating domestic sewage is prepared by the following steps:

[0109] (1) 10.0 parts by weight of dried apple pomace were crushed and passed through a 100-mesh sieve. Each time, it was washed 2-3 times with 50 parts of pure water at 50 ℃. Then, it was added to 50 parts of 6.0 mol / L hydrochloric acid and the pH was adjusted to 1.5. The mixture was stirred at 300 r / min for 2.5 h in a 95 ℃ water bath. Each time, it was washed repeatedly with 20 parts of 80% ethanol until the filtrate was neutral. Then, it was dried at 50 ℃, ground, and passed through a 100-mesh sieve to obtain component B.

[0110] (2) Adjust component B to pH 4.0 with 1.0 mol / L hydrochloric acid or NaOH solution, stir at 300 r / min for 3.0 h at 70 ℃, let stand for 24.0 h, dry at 50 ℃, grind through a 150 mesh sieve to obtain flocculant.

[0111] Example of effect

[0112] The flocculants obtained in Examples 1-5 and Comparative Examples 1-2, as well as commercially available PAC and PAM, were subjected to performance testing. The specific method was as follows: Nine equal amounts of domestic sewage were taken from the same water source. 40g of flocculant (the flocculant from Examples 1-5, PAC, PAM, and the flocculant from Comparative Examples 1-2) was added to each sewage sample. The nine sewage samples with the added flocculant were simultaneously stirred at 100 r / min for 0.5h at room temperature, then allowed to stand for 6h, filtered, and the quality of the nine treated water samples was tested. The results are shown in Table 1. The reference standard was the Class V standard requirements of the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0113] Table 1. Treatment effect of flocculants on domestic sewage

[0114]

[0115] As shown in Table 1, after treatment with the flocculants obtained in Examples 1-5, the removal rates of turbidity, color, BOD5, and COD in domestic sewage reached as high as 96.9%, 98.1%, 96.5%, and 86.5%, respectively, significantly higher than those of PAC and PAM at the same dosage. In Comparative Examples 1 and 2, the flocculants prepared solely using modified loess and modified apple pomace still showed far lower flocculation effects than the flocculant solution provided in this invention. This indirectly verifies that the technology provided in this invention is not a simple superposition of modified loess and modified apple pomace solutions; it has achieved a 1+1>2 flocculation effect in the treatment of domestic sewage, particularly demonstrating significant technical advantages in the removal of turbidity, color, BOD5, COD, and fecal coliforms.

[0116] The water treated with the flocculant of this invention meets the Class V standard requirements of the "Surface Water Environmental Quality Standard" (GB 3838-2002) and can be used for agricultural and general landscape water.

[0117] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. The application of a high-efficiency flocculant for domestic sewage treatment in the field of domestic sewage treatment, characterized in that, The high-efficiency domestic sewage treatment flocculant includes component A and component B; Component A is an inorganic polymer obtained by using loess as the silicon, aluminum, and iron source alone, through alkali fusion, acid leaching, and polymerization processes; it plays a role in the flocculant by binding and agglomeration, adsorption and charge neutralization, adsorption bridging, and sweeping and trapping. Component B is an organic polymer obtained by crushing and sieving apple pomace, washing it with warm water, acid soaking, washing it with ethanol, drying it, grinding it, and sieving it. It acts as an emulsifier and gelling agent in flocculants, and also provides a carrier for component A, improving the stability of component A; the acid leaching conditions are as follows: 5.0~7.0 mol / L hydrochloric acid and apple pomace are mixed in a weight ratio of 5:1, the pH of the system is adjusted to 1.5~2.0, and the mixture is stirred in a water bath for 2.0~3.0 h; ethanol washing: the mixture is repeatedly washed with 80~95% ethanol until the filtrate is neutral; Component A and component B are mixed in a weight ratio of (23~28):

10. The pH of the system is adjusted to 3.5~4.5 with hydrochloric acid or NaOH solution. The mixture is heated and stirred, allowed to stand for maturation, dried, and ground to obtain the flocculant. The heating and stirring conditions are: stirring at 200~400 r / min at 70~80℃ for 2.5~3.5 h; the maturation time is 24.0~36.0 h. The application method of the high-efficiency domestic sewage treatment flocculant in the field of domestic sewage treatment includes: adding 36.0~45.0 g of the flocculant per cubic meter of domestic sewage with a pH range of 4.0~10.0, stirring, settling, and filtering at room temperature, and the water quality can meet the Class V standard requirements of the "Surface Water Environmental Quality Standard" (GB 3838-2002); the filtered residue can be recycled or biodegraded.

2. The application of the high-efficiency domestic sewage treatment flocculant as described in claim 1 in the field of domestic sewage treatment, characterized in that, The preparation method of component A includes the following steps: S1. Disperse loess in pure water and allow it to settle naturally. Remove the upper suspension and the bottom fine sand particles and impurities. Take the middle loess slurry, centrifuge, dry, crush and sieve it to obtain loess powder. S2. After uniformly mixing loess powder with Na2CO3, the mixture is calcined, ground, acid-leached, diluted with water, and then filtered to obtain filtrate I and filter residue. S3. The filter residue is alkali-leached and filtered. The resulting filtrate II is acidified and polymerized, then mixed with filtrate I, alkalized and aged to obtain component A.

3. The application of the high-efficiency domestic sewage treatment flocculant as described in claim 2 in the field of domestic sewage treatment, characterized in that, In step S2: The ratio of loess powder to Na2CO3 by weight is (18~22):(3~7); Calcination conditions: Calcination in a muffle furnace at 700~850 ℃ for 2.0~2.5 h; Acid leaching conditions: Mix 5.0~7.0 mol / L hydrochloric acid with loess powder in a weight ratio of (4.0~5.0):1, and then stir and leach in a water bath for 1.5~3.0 h; In step S3: Alkali leaching conditions: Mix 5.0~7.0 mol / L NaOH solution with the filter residue and leach in a water bath for 1.0~2.5 h with stirring; wherein the ratio of NaOH solution to loess powder by weight is (2.0~2.5):1; Acidification conditions: Add 1.0 mol / L hydrochloric acid solution to filtrate II to adjust the pH to 1.8~2.2; Polymerization conditions: Stirred polymerization at room temperature for 2.0–2.5 h, followed by static activation for 2.0–3.0 h; Alkalization conditions: In a water bath environment, slowly add 0.30 mol / L NaOH solution dropwise over 0.5 h to adjust the pH of the system to 5.8~6.2, and continue stirring for 0.5~1.0 h to prevent precipitation; Aging conditions: Aging at room temperature for 12.0~18.0 h.

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