A treatment process for polyester wastewater containing antimony
Patent Information
- Application Number
- CN202611080821.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-21
- Publication Date
- 2026-08-21
AI Technical Summary
[0004]本发明的目的是提供一种聚酯含锑废水的处理工艺，旨在解决现有含锑废水处理方法难以兼顾Sb(III)和Sb(V)同步高效去除、低浓度下处理效率低难以稳定达标排放、吸附材料成本高等技术问题
[0022] This invention solves the problem of the coexistence of Sb(III) and Sb(V) in wastewater, which makes it difficult for traditional methods to remove them simultaneously and efficiently. It also addresses the technical bottleneck of traditional methods failing due to "organic encapsulation" caused by the strong complexation of antimony with large amounts of ethylene glycol and oligomers in actual polyester production wastewater. The invention significantly improves the antimony removal agent's resistance to organic interference under complex water conditions and its efficiency in deep treatment of high-concentration antimony-containing wastewater. Furthermore, it addresses the current situation where existing deep antimony removal materials require excessive dosage in practical applications, easily generating large amounts of hazardous sludge and thus increasing the enterprise's hazardous waste disposal costs.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of wastewater treatment technology, and specifically to a treatment process for antimony-containing polyester wastewater. Background Technology
[0002] Antimony glycolate is commonly used as a polycondensation catalyst in the production of polyester (PET). During polyester production and subsequent processes such as cleaning and dyeing, antimony from the catalyst enters the wastewater system, forming antimony-containing wastewater. Antimony and its compounds are highly toxic and have been listed as priority pollutants by many countries.
[0003] Currently, the main methods for treating antimony-containing wastewater include sedimentation, coagulation, adsorption, and biological methods. Traditional coagulation and sedimentation methods use inorganic iron or aluminum salts as flocculants. However, actual polyester wastewater not only contains both Sb(III) and Sb(V) valence states, but also typically contains high concentrations of ethylene glycol and polyester oligomers. These organic compounds form extremely stable soluble complexes with antimony ions, resulting in traditional coagulants being ineffective at removing Sb(III) and unable to break the organic complexes, thus failing to stably treat total antimony to below the national standard (0.10 mg / L). On the other hand, while adsorption methods (such as modified activated carbon and molecular sieves) can achieve deep treatment, the adsorption materials are easily poisoned and deactivated in wastewater with high organic concentrations, are difficult to regenerate, and have high operating costs. Therefore, this invention provides a treatment process for antimony-containing polyester wastewater. Summary of the Invention
[0004] The purpose of this invention is to provide a treatment process for antimony-containing polyester wastewater, aiming to solve the technical problems of existing antimony-containing wastewater treatment methods, such as difficulty in simultaneously and efficiently removing Sb(III) and Sb(V), low treatment efficiency at low concentrations making it difficult to achieve stable emission standards, and high cost of adsorption materials.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0006] A process for treating antimony-containing polyester wastewater includes the following steps: adjusting the pH of the antimony-containing polyester wastewater to 7.5-8.5, adding a composite antimony removal agent to the wastewater at a dosage of 50-150 mg / L, reacting under stirring conditions for 20-40 min, allowing the mixture to settle after the reaction, and separating the solid and liquid components; the composite antimony removal agent is composed of a modified iron-based component and a modified chitosan component in a mass ratio of (3-5):1, wherein the modified iron-based component is an iron-manganese composite oxide obtained by co-precipitation of ferrous sulfate heptahydrate and manganese sulfate monohydrate and calcination, and the modified chitosan component is obtained by functionalizing chitosan nanoparticles cross-linked with sodium tripolyphosphate with carbon disulfide and sodium hydroxide solution.
[0007] Further, the preparation method of the modified iron-based component includes: dissolving ferrous sulfate heptahydrate and manganese sulfate monohydrate in deionized water to prepare a mixed salt solution; adding alkaline solution dropwise to the mixed salt solution under stirring until the pH is 7.5-8.5, so that iron ions and manganese ions co-precipitate to form an iron-manganese complex hydroxide precursor; separating, washing, and drying the obtained precipitate, and then calcining it at 350-450°C for 2-4 hours in an air atmosphere to obtain the modified iron-based component;
[0008] Furthermore, the mass ratio of ferrous sulfate heptahydrate to manganese sulfate monohydrate is (8~10):1.
[0009] Furthermore, the total metal ion concentration in the mixed salt solution is 0.5~1.0 mol / L.
[0010] Further, the preparation method of the modified chitosan component includes: dissolving chitosan in acetic acid solution to prepare a chitosan solution; adding sodium tripolyphosphate to the chitosan solution under stirring to carry out a cross-linking reaction to form a chitosan nanoparticle suspension; adding carbon disulfide and sodium hydroxide solution to the chitosan nanoparticle suspension, stirring and reacting at 40~50℃ for 2~4h, and then separating, washing and drying to obtain the modified chitosan component.
[0011] Furthermore, in the preparation of the modified iron-based component, the drying temperature is 60~80℃ and the drying time is 12~24h.
[0012] Furthermore, in the preparation of the modified iron-based component, the calcination heating rate is 5~10℃ / min.
[0013] Furthermore, the degree of deacetylation of the chitosan is ≥90%.
[0014] Furthermore, the chitosan solution contains 2-3% chitosan by mass.
[0015] Furthermore, the mass ratio of sodium tripolyphosphate to chitosan is (1~2):10.
[0016] Furthermore, the mass ratio of carbon disulfide to chitosan is (3~5):10.
[0017] Furthermore, the crosslinking reaction is carried out at room temperature for 1-2 hours.
[0018] Furthermore, in the preparation of the modified chitosan component, the drying is performed by vacuum drying at 50°C for 24 hours.
[0019] Furthermore, the stirring speed is 60~100 rpm.
[0020] Furthermore, the settling time is 30-60 minutes.
[0021] The beneficial effects of this invention are as follows:
[0022] This invention solves the problem of the coexistence of Sb(III) and Sb(V) in wastewater, which makes it difficult for traditional methods to remove them simultaneously and efficiently. It also addresses the technical bottleneck of traditional methods failing due to "organic encapsulation" caused by the strong complexation of antimony with large amounts of ethylene glycol and oligomers in actual polyester production wastewater. The invention significantly improves the antimony removal agent's resistance to organic interference under complex water conditions and its efficiency in deep treatment of high-concentration antimony-containing wastewater. Furthermore, it addresses the current situation where existing deep antimony removal materials require excessive dosage in practical applications, easily generating large amounts of hazardous sludge and thus increasing the enterprise's hazardous waste disposal costs.
[0023] This invention combines iron-manganese composite oxides with dithiocarbamic acid (DTC)-functionalized chitosan nanoparticles. The manganese(IV) in the modified iron-based component possesses extremely strong oxidizing properties, instantly converting difficult-to-treat Sb(III) in wastewater into easily adsorbed Sb(V). The strong adsorption of the iron-manganese oxides combined with the strong complexing and chelating effects of the DTC groups result in the stereotactic capture of antimony ions in different valence states, overcoming the bottleneck of low removal rates with a single mechanism. Although the modified iron-based component contains highly oxidizing manganese(IV), while the modified chitosan component contains reducing DTC groups, the two are combined in a solid-phase powder state, exhibiting a significant steric hindrance effect. Furthermore, in terms of reaction kinetics, manganese(IV) oxidizes free and complexed Sb(III) in the aqueous phase extremely quickly (instantaneously), while oxidizing the DTC groups within the solid-phase cross-linked network is extremely slow. This perfectly avoids the self-consumption and internal friction conflicts that occur when strong oxidants and strong reducing agents are combined, ensuring synergistic effects between the two.
[0024] This invention addresses the problem that organic substances such as ethylene glycol in polyester wastewater readily form stable complexes with antimony. The DTC-functionalized chitosan of this invention can competitively disrupt the "antimony-ethylene glycol" complex, releasing antimony ions. At the same time, the three-dimensional nano-crosslinked network of the modified chitosan itself has a high density of active sites, which can exert excellent charge neutralization and net-catching sweeping effects. Meanwhile, iron and manganese oxide particles act as crystal nuclei and are wrapped by the chitosan network, causing the chelated antimony to form dense and high-density flocs that settle. Even without the addition of additional polymeric coagulants, good mud-water separation can still be achieved within a reasonable settling time.
[0025] In this invention, the composite antimony removal agent can stably reduce the total antimony to below 0.05 mg / L even in harsh water conditions where the total antimony in the raw water is as high as 2.5 mg / L or more and contains a high amount of organic matter.
[0026] All raw materials used in this invention are environmentally friendly, and no other toxic or harmful substances are introduced during the antimony removal process. Chitosan is a natural polymer material with biodegradability; iron-manganese composite oxide is an inorganic mineral material with good chemical stability and can be treated using conventional sludge disposal methods after use, resulting in low environmental risk. Detailed Implementation
[0027] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0028] It should also be noted that the chitosan (degree of deacetylation ≥90%, industrial grade), CAS: 9012-76-4, used in this invention was purchased from Wuhan Linsheng Technology Co., Ltd.
[0029] Example 1
[0030] This embodiment provides a treatment process for antimony-containing wastewater from polyester, the steps of which include:
[0031] (I) Preparation of modified iron-based components
[0032] 90 g of ferrous sulfate heptahydrate (FeSO4·7H2O) and 10 g of manganese sulfate monohydrate (MnSO4·H2O) were dissolved in deionized water to prepare a mixed salt solution (approximately 450 mL) with a total metal ion concentration of 0.8 mol / L. Under mechanical stirring at 300 rpm, 1.0 mol / L sodium hydroxide solution was slowly added dropwise to the mixed salt solution until the pH reached 8.0, causing iron and manganese ions to co-precipitate and form an iron-manganese complex hydroxide precursor. The resulting precipitate was centrifuged, washed three times with deionized water, and then dried in a 70℃ oven for 18 h. The dried precursor was placed in a muffle furnace and calcined at 400℃ in air at a heating rate of 8℃ / min for 3 h. After calcination, it was naturally cooled to room temperature and ground through a 200-mesh sieve to obtain the modified iron-based component.
[0033] (II) Preparation of modified chitosan component
[0034] 10 g of chitosan (92% degree of deacetylation) was dissolved in 2% acetic acid solution to prepare a 2.5% chitosan-acetic acid solution (400 mL). The solution was stirred at 300 rpm until completely dissolved. Under stirring at 300 rpm, 30 mL of a 5% sodium tripolyphosphate (STPP) aqueous solution (STPP to chitosan mass ratio of 1.5:10) was slowly added dropwise to the above chitosan solution. The cross-linking reaction was continued at room temperature for 1.5 h to form a chitosan nanoparticle suspension.
[0035] Add 4 g of carbon disulfide to the above suspension, and add 1.0 mol / L sodium hydroxide solution dropwise under stirring at 300 rpm to maintain the pH of the system at 8.5 (the mass ratio of carbon disulfide to chitosan is 4:10). Maintain the reaction at 300 rpm for 3 h under water bath conditions at 45℃ to modify the amino groups on the surface of chitosan by dithiocarboxylation, and obtain a DTC-functionalized chitosan nanoparticle suspension.
[0036] The above suspension was centrifuged, washed with deionized water until neutral, vacuum dried at 50°C for 24 hours, and ground through a 200-mesh sieve to obtain the modified chitosan component.
[0037] (III) Formulation of composite antimony removal agents
[0038] The modified iron-based component and the modified chitosan component are mixed uniformly at a mass ratio of 4:1 to obtain the composite antimony removal agent.
[0039] (iv) Treatment of antimony-containing wastewater
[0040] Wastewater from a polyester chip factory was collected. The wastewater had a COD of approximately 800 mg / L and contained organic matter such as ethylene glycol. The total antimony content was measured to be 2.52 mg / L (of which Sb(III) accounted for approximately 35% and Sb(V) approximately 65%). The pH was adjusted to 8.0. The aforementioned composite antimony removal agent was added to the wastewater at a dosage of 100 mg / L (based on wastewater volume), and the reaction was carried out for 30 minutes under stirring conditions (stirring speed 80 rpm). After the reaction was completed, the mixture was allowed to settle for 45 minutes, and solid-liquid separation was performed. The total antimony content of the supernatant was determined.
[0041] The total antimony content in the treated effluent was measured to be 0.02 mg / L, which is far below the emission limit of GB4287-2012.
[0042] Example 2
[0043] This embodiment provides a treatment process for antimony-containing wastewater from polyester, the steps of which include:
[0044] (I) Preparation of modified iron-based components
[0045] 80 g of ferrous sulfate heptahydrate and 10 g of manganese sulfate monohydrate were dissolved in deionized water to prepare a mixed salt solution (approximately 694 mL) with a total metal ion concentration of 0.5 mol / L. Under mechanical stirring, 1.0 mol / L sodium hydroxide solution was slowly added dropwise to the mixed salt solution until the pH reached 7.5, causing iron and manganese ions to co-precipitate and form an iron-manganese complex hydroxide precursor. The resulting precipitate was centrifuged, washed three times with deionized water, and then dried in a 60°C oven for 24 h. The dried precursor was then placed in a muffle furnace and calcined at 350°C at a heating rate of 5°C / min in air atmosphere for 4 h. After calcination, the mixture was allowed to cool naturally to room temperature and then ground through a 200-mesh sieve to obtain the modified iron-based component.
[0046] (II) Preparation of modified chitosan component
[0047] 10 g of chitosan (90% degree of deacetylation) was dissolved in 2% acetic acid solution to prepare a 2% chitosan-acetic acid solution (500 mL), and stirred until completely dissolved. Under stirring conditions, 20 mL of a 5% sodium tripolyphosphate (STPP) aqueous solution (STPP to chitosan mass ratio of 1:10) was slowly added dropwise to the above chitosan solution, and the cross-linking reaction was continued at room temperature for 1 h to form a chitosan nanoparticle suspension.
[0048] Add 3 g of carbon disulfide to the above chitosan nanoparticle suspension, and add 1.0 mol / L sodium hydroxide solution dropwise under stirring to maintain the pH of the system at 8.5 (the mass ratio of carbon disulfide to chitosan is 3:10). Stir the reaction in a 40℃ water bath for 4 h to obtain a DTC-functionalized chitosan nanoparticle suspension.
[0049] The above suspension was centrifuged, washed with deionized water until neutral, vacuum dried at 50°C for 24 hours, and ground through a 200-mesh sieve to obtain the modified chitosan component.
[0050] (III) Formulation of composite antimony removal agents
[0051] The modified iron-based component and the modified chitosan component are mixed uniformly at a mass ratio of 3:1 to obtain the composite antimony removal agent.
[0052] (iv) Treatment of antimony-containing wastewater
[0053] The aforementioned polyester wastewater (total antimony content 2.48 mg / L, of which Sb(III) accounts for approximately 30% and Sb(V) accounts for approximately 70%) was taken and the pH was adjusted to 7.5. The aforementioned composite antimony removal agent was added to the wastewater at a dosage of 50 mg / L, and the reaction was carried out for 20 min under stirring conditions (stirring speed 60 rpm). After the reaction was completed, the mixture was allowed to stand for 30 min to settle, and the solid and liquid were separated. The total antimony content of the supernatant was determined.
[0054] The total antimony content in the treated effluent was measured to be 0.03 mg / L, which is far below the emission limit of GB4287-2012.
[0055] Example 3
[0056] This embodiment provides a treatment process for antimony-containing wastewater from polyester, the steps of which include:
[0057] (I) Preparation of modified iron-based components
[0058] 100 g of ferrous sulfate heptahydrate and 10 g of manganese sulfate monohydrate were dissolved in deionized water to prepare a mixed salt solution (approximately 410 mL) with a total metal ion concentration of 1.0 mol / L. Under mechanical stirring, 1.0 mol / L sodium hydroxide solution was slowly added dropwise to the mixed salt solution until the pH reached 8.5, causing iron and manganese ions to co-precipitate and form an iron-manganese complex hydroxide precursor. The resulting precipitate was centrifuged, washed three times with deionized water, and then dried in an oven at 80°C for 12 h. The dried precursor was then placed in a muffle furnace and calcined at 450°C at a heating rate of 10°C / min in air atmosphere for 2 h. After calcination, the mixture was allowed to cool naturally to room temperature and then ground through a 200-mesh sieve to obtain the modified iron-based component.
[0059] (II) Preparation of modified chitosan component
[0060] 10 g of chitosan (95% degree of deacetylation) was dissolved in 2% acetic acid solution to prepare a 3% chitosan-acetic acid solution (approximately 333 mL). The solution was stirred until completely dissolved. Under stirring conditions, 40 mL of a 5% sodium tripolyphosphate (STPP) aqueous solution (STPP to chitosan mass ratio of 2:10) was slowly added dropwise to the above chitosan solution. The cross-linking reaction was continued at room temperature for 2 hours to form a chitosan nanoparticle suspension.
[0061] Add 5 g of carbon disulfide to the above chitosan nanoparticle suspension, and add 1.0 mol / L sodium hydroxide solution dropwise under stirring to maintain the pH of the system at 8.5 (the mass ratio of carbon disulfide to chitosan is 3:10). Stir the reaction in a 50℃ water bath for 2 h to obtain a DTC-functionalized chitosan nanoparticle suspension.
[0062] The above suspension was centrifuged, washed with deionized water until neutral, vacuum dried at 50°C for 24 hours, and ground through a 200-mesh sieve to obtain the modified chitosan component.
[0063] (III) Formulation of composite antimony removal agents
[0064] The modified iron-based component and the modified chitosan component are mixed uniformly at a mass ratio of 5:1 to obtain the composite antimony removal agent.
[0065] (iv) Treatment of antimony-containing wastewater
[0066] The aforementioned polyester wastewater (total antimony content 2.65 mg / L, of which Sb(III) accounts for approximately 40% and Sb(V) approximately 60%) was taken and the pH was adjusted to 8.5. The aforementioned composite antimony removal agent was added to the wastewater at a dosage of 150 mg / L, and the reaction was carried out for 40 min under stirring conditions (stirring speed 100 rpm). After the reaction was completed, the mixture was allowed to stand for 60 min to settle, and the solid and liquid were separated. The total antimony content of the supernatant was determined.
[0067] The total antimony content in the treated effluent was measured to be 0.02 mg / L, which is far below the emission limit of GB4287-2012.
[0068] Unless otherwise stated, the parts of Examples 2 and 3 are the same as those in Example 1.
[0069] Comparative Example 1
[0070] The difference from Example 1 is that the mass ratio of the iron-based component and the chitosan component was adjusted to 1:1. Due to the high concentration of antimony in the raw wastewater and the presence of organic matter, the iron-based component was too low, resulting in insufficient Sb(III) oxidation. The total antimony in the effluent was 0.45 mg / L, which did not meet the standard.
[0071] Comparative Example 2
[0072] The difference from Example 1 is that the compound mass ratio was adjusted to 8:1. The chitosan component was too low, failing to effectively break the complexation effect of ethylene glycol on antimony, resulting in a total antimony concentration of 0.18 mg / L in the effluent, which did not meet the standard.
[0073] Comparative Example 3
[0074] The difference from Example 1 is that manganese sulfate monohydrate was not added in the preparation of the iron-based component. Due to the lack of efficient oxidation by Mn(IV), the removal of Sb(III) from the wastewater was extremely poor, with the total antimony in the effluent reaching as high as 0.82 mg / L, which seriously failed to meet the standards.
[0075] Comparative Example 4
[0076] The difference from Example 1 is that manganese sulfate monohydrate was replaced with an equimolar amount of copper sulfate pentahydrate. The total antimony in the effluent was 0.25 mg / L, which not only failed to meet the standard but also easily caused secondary copper pollution.
[0077] Comparative Example 5
[0078] The difference from Example 1 is that sodium tripolyphosphate was not added for cross-linking in the preparation of the chitosan component. Chitosan did not form nanoparticles and therefore could not exert its flocculation effect of netting and sweeping in wastewater with high organic matter content, resulting in a total antimony concentration of 0.35 mg / L in the effluent.
[0079] Comparative Example 6
[0080] The difference from Example 1 is that carbon disulfide and alkali were not added for modification during the preparation of the chitosan component. Lacking the crucial dithiocarboxyl group, it could not compete with ethylene glycol for chelating antimony ions, resulting in a total antimony concentration of 0.55 mg / L in the effluent, which did not meet the standard.
[0081] Comparative Example 7
[0082] The difference from Example 1 is that no compounding was performed; instead, a step-by-step addition method was used, first adding the iron-based component for 20 minutes, then adding the chitosan component for 20 minutes. Although the total antimony in the effluent decreased to 0.08 mg / L, it did not reach below 0.05 mg / L due to the lack of synchronous synergistic effect, and the process was cumbersome.
[0083] Comparative Example 8
[0084] The difference from Example 1 is that the wastewater pH is not adjusted during use (the raw water pH is 6.5). Acidic conditions are not conducive to the dissociation and chelation precipitation of complexes, resulting in a total antimony concentration in the effluent as high as 0.95 mg / L.
[0085] Test case
[0086] The water quality indicators and settling performance of the effluents obtained from Examples 1-3 and Comparative Examples 1-8 were measured. The specific test methods are as follows:
[0087] (1) Total antimony content: The content shall be determined in accordance with the current national standard HJ 1047-2019 "Determination of antimony in water by graphite furnace atomic absorption spectrophotometry";
[0088] (2) Antimony removal rate: = (Total antimony in raw water - Total antimony in effluent) / Total antimony in raw water × 100%;
[0089] (3) Flocculation and sedimentation time: Record the time required from the start of the reaction stage when stirring stops until the flocs in the wastewater have completely settled to the bottom and the supernatant becomes clear and free of obvious suspended matter.
[0090] The results are shown in Table 1 below:
[0091] Table 1
[0092] Based on the data in Table 1 above, it can be seen that when dealing with harsh polyester wastewater with a total antimony concentration of over 2.5 mg / L and containing organic complexes (high COD), Examples 1-3 not only require an extremely low dosage of 50~150 mg / L to stably reduce the total antimony concentration in the effluent to below 0.05 mg / L (with a removal rate of over 98.8%), but also exhibit excellent settling performance, successfully achieving a balance between deep treatment and rapid treatment.
[0093] In Comparative Example 1, the proportion of modified iron-based components was too low, resulting in insufficient oxidation of Sb(III) in high-concentration wastewater and a severely inadequate overall adsorption capacity. In Comparative Example 2, the proportion of modified chitosan components was too low, failing to provide sufficient DTC groups to break the strong complexation of organic matter with antimony. Furthermore, the insufficient polymer cross-linking network led to a significant extension of the settling time. Once the proportion of both components deviated from the limits defined in this invention, the balance between oxidation adsorption and competitive chelation was disrupted, resulting in substandard effluent.
[0094] In Comparative Example 3, the modified iron-based component lacked the oxidation effect of Mn(IV), resulting in a large amount of difficult-to-treat Sb(III) residue and a sharp drop in removal rate.
[0095] Comparative Example 4 uses copper instead of manganese, which not only fails to achieve synergy between oxidation and adsorption performance, resulting in substandard antimony removal, but also easily introduces copper ions, causing secondary environmental pollution. From both environmental protection and effectiveness perspectives, it is inferior to the preferred solution of this invention.
[0096] In Comparative Example 5, the modified chitosan lacked STPP crosslinking and failed to form a three-dimensional nanoparticle structure, which resulted in its inability to exert a net-capture and sweeping flocculation effect in wastewater with high organic matter content. The flocs were small and loose, and it was still difficult to achieve effective solid-liquid separation even after a settling time of more than 60 minutes.
[0097] Comparative Example 6 lacked the key DTC functionalization modification and lacked the core chelating functional group of dithiocarboxyl group, which caused the antimony removal agent to completely lose its ability to compete with ethylene glycol to capture antimony ions, resulting in a serious excess of total antimony in the effluent.
[0098] Comparative Example 7 adopted a step-by-step addition method, which interrupted the synergistic capture effect of iron-manganese oxide and modified chitosan in the same space, resulting in large floc particles being difficult to form quickly (settling time increased to 62 min), the effluent concentration failing to stabilize below 0.05 mg / L, and the process operation being more cumbersome, far less convenient than the one-step addition method of this invention.
[0099] In Comparative Example 8, the pH of the wastewater was not controlled (it was acidic), which made it difficult for the organic complexes to dissociate. This not only slowed down the sedimentation, but also caused a sharp decline in the efficiency of both adsorption and chelation active sites, resulting in a removal rate of only 62.3%.
[0100] Finally, it should be noted that the above embodiments and comparative examples are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.
Claims
1. A treatment process for antimony-containing wastewater from polyester plants, characterized in that, Includes the following steps: The pH of the polyester antimony-containing wastewater was adjusted to 7.5-8.5, and a composite antimony removal agent was added to the wastewater at a dosage of 50-150 mg / L. The reaction was carried out under stirring for 20-40 minutes. After the reaction was completed, the mixture was allowed to stand and settle, and the solid and liquid were separated. The composite antimony removal agent was composed of a modified iron-based component and a modified chitosan component in a mass ratio of (3-5):
1. The modified iron-based component was an iron-manganese composite oxide obtained by co-precipitation of ferrous sulfate heptahydrate and manganese sulfate monohydrate and then calcination. The modified chitosan component was obtained by functionalizing chitosan nanoparticles cross-linked with sodium tripolyphosphate with carbon disulfide and sodium hydroxide solution.
2. The treatment process for antimony-containing polyester wastewater according to claim 1, characterized in that, The preparation method of the modified iron-based component includes: dissolving ferrous sulfate heptahydrate and manganese sulfate monohydrate in deionized water to prepare a mixed salt solution; adding alkali solution dropwise to the mixed salt solution under stirring until the pH is 7.5-8.5, so that iron ions and manganese ions co-precipitate to form an iron-manganese complex hydroxide precursor; separating, washing and drying the obtained precipitate, and calcining it at 350-450°C for 2-4 h in an air atmosphere to obtain the modified iron-based component.
3. The treatment process for antimony-containing polyester wastewater according to claim 2, characterized in that, The mass ratio of ferrous sulfate heptahydrate to manganese sulfate monohydrate is (8~10):1; the total metal ion concentration in the mixed salt solution is 0.5~1.0 mol / L.
4. The treatment process for antimony-containing polyester wastewater according to claim 1, characterized in that, The method for preparing the modified chitosan component includes: dissolving chitosan in acetic acid solution to prepare a chitosan solution; adding sodium tripolyphosphate to the chitosan solution under stirring to carry out a cross-linking reaction to form a chitosan nanoparticle suspension; adding carbon disulfide and sodium hydroxide solution to the chitosan nanoparticle suspension, stirring the reaction at 40~50℃ for 2~4 h, and then separating, washing, and drying to obtain the modified chitosan component.
5. The treatment process for antimony-containing polyester wastewater according to claim 2, characterized in that, In the preparation of the modified iron-based component, the drying temperature is 60~80℃ and the drying time is 12~24 h; the calcination heating rate is 5~10℃ / min.
6. The treatment process for antimony-containing polyester wastewater according to claim 4, characterized in that, The degree of deacetylation of the chitosan is ≥90%; the mass fraction of chitosan in the chitosan solution is 2~3%.
7. The treatment process for antimony-containing polyester wastewater according to claim 4, characterized in that, The mass ratio of sodium tripolyphosphate to chitosan is (1~2):10; the cross-linking reaction is carried out at room temperature for 1~2 h.
8. The treatment process for antimony-containing polyester wastewater according to claim 4, characterized in that, The mass ratio of carbon disulfide to chitosan is (3~5):10; in the preparation of the modified chitosan component, the drying is vacuum drying at 50℃ for 24h.
9. The treatment process for antimony-containing polyester wastewater according to claim 1, characterized in that, The stirring speed is 60~100 rpm; the settling time is 30~60 min.