A detoxification-aerobic biological trickling filter treatment method for PTT fiber production waste gas

Abstract

The application discloses a detoxification-aerobic biological trickling filtration treatment method for PTT fiber production waste gas, and belongs to the technical field of industrial waste gas biological treatment. In view of the problem that waste gas with propylene aldehyde as a characteristic component in polypropylene terephthalate fiber production is difficult to be stably treated by a biological method because propylene aldehyde has a biocidal property, the method comprises a front-end detoxification pretreatment step and an aerobic biological trickling filtration step: the waste gas is contacted with an absorption liquid, the carbon-carbon double bond of propylene aldehyde in the liquid phase is consumed by means of a hydration reaction and / or an addition reaction with added bisulfite, the concentration peak of propylene aldehyde in the waste gas and the toxicity of propylene aldehyde to microorganisms are reduced, and detoxified gas is obtained; and then the detoxified gas is introduced into an aerobic biological trickling filtration tower provided with circulating liquid, and propylene aldehyde and optional propylene alcohol and methanol in the detoxified gas are degraded by an aerobic microbial biofilm loaded on the filler.

Description

Technical Field

[0001] This invention discloses a detoxification-aerobic biological trickling filtration method for waste gas from PTT fiber production, belonging to the field of industrial waste gas biological treatment technology. Background Technology

[0002] Polypropylene terephthalate (PTT) fiber is produced by esterification or transesterification of terephthalic acid or dimethyl terephthalate with 1,3-propanediol, followed by polycondensation and melt spinning. It exhibits excellent elastic recovery and is widely used in clothing, carpets, and home textiles. During the esterification, polycondensation, and subsequent melt spinning processes, the 1,3-propanediol segments and dipropylene glycol structural units undergo thermal and oxidative degradation at high temperatures, releasing volatile organic compounds (VOCs) characterized by acrolein and allyl alcohol, accompanied by low-molecular-weight aldehydes such as methanol and acetaldehyde. These VOCs typically have large volumes, relatively low concentrations, and exhibit peak concentrations that fluctuate with production conditions. Effective treatment of these VOCs is a key issue to be addressed in the clean production of PTT fibers.

[0003] For volatile organic compounds (VOCs), common treatment technologies include combustion, adsorption, and biological methods. Combustion is energy-intensive and costly for low-concentration, high-volume VOCs and may cause secondary pollution. Adsorption only transfers pollutants from the gas phase to the solid phase; the adsorbent needs regeneration or disposal as hazardous waste, failing to achieve final elimination of pollutants. Biological methods utilize microorganisms to degrade pollutants, offering advantages such as low energy consumption and no secondary pollution. Furthermore, the main components of this type of VOC, such as acrolein, allyl alcohol, and methanol, are highly water-soluble, making them theoretically suitable for biological treatment from a mass transfer perspective.

[0004] However, applying biological methods to this type of waste gas presents a well-known obstacle: acrolein, a characteristic component of this waste gas, is itself highly biotoxic and has been used as an algaecide, slime bactericide, and biocide in circulating water systems, exhibiting strong inhibitory and even lethal effects on microorganisms. Therefore, those skilled in the art generally believe that acrolein-containing waste gas is not suitable for direct biological treatment, and existing technologies objectively tend to move away from directly introducing this type of waste gas into a bioreactor. Practice shows that if conventional bio-trickling and bio-washing processes used for common volatile organic compounds such as toluene and xylene are directly applied to this type of waste gas, the microorganisms responsible for degradation will be inhibited by acrolein. Especially when production conditions fluctuate or acrolein concentration experiences a surge, biofilm activity drops sharply or even collapses, and the damaged microbial community recovers slowly. Therefore, simply transplanting biological treatment technologies for common volatile organic compounds to this type of acrolein-containing waste gas makes it difficult to establish and maintain a biological treatment system.

[0005] Furthermore, the fluctuating concentration of this type of waste gas under varying operating conditions and the tendency to experience peak concentrations exacerbate the aforementioned difficulties: the acrolein toxicity load reaching the biofilm during peak concentration periods increases sharply, making it easier to exceed the tolerance limits of microorganisms and cause irreversible damage, for which existing technologies lack corresponding buffering and protective measures. Simultaneously, there is a lack of suitable methods for identifying the sources of microorganisms responsible for degradation and for establishing their domestication in the presence of acrolein.

[0006] In summary, for PTT fiber production waste gas, which is characterized by acrolein and whose concentration fluctuates with operating conditions, existing technologies lack a treatment process and system that can overcome the biocidal inhibition of acrolein on microorganisms and cope with its peak concentration impact, thereby enabling the establishment and stable operation of a biological treatment system. Summary of the Invention

[0007] To address the above problems, this invention provides a biological treatment method for acrolein-containing waste gas, comprising the following steps:

[0008] (1) Front-end detoxification pretreatment step: The waste gas is brought into contact with the absorbent liquid, and the peak concentration of acrolein in the waste gas and its toxicity to microorganisms are reduced by means of the hydration reaction of acrolein in water and / or the addition reaction of acrolein with the added bisulfite, so as to obtain the detoxified gas.

[0009] (2) Aerobic biological trickling filtration step: The detoxified gas is passed into an aerobic biological trickling filter tower equipped with circulating liquid, where the aerobic microbial biofilm loaded on the packing material degrades acrolein and optionally acrylonitrile alcohol and methanol to obtain purified gas.

[0010] Furthermore, the waste gas is a volatile organic waste gas containing acrolein and accompanied by acrylonitrile alcohol and / or methanol, generated during the polymerization and / or spinning processes in the production of polypropylene terephthalate fiber.

[0011] Furthermore, in the pretreatment of the front-end detoxification, the pH of the absorbent is controlled to be 7.5 to 9.0, the residence time of the absorbent in the detoxification liquid circulation reaction tank is controlled to be 10 to 60 min, and the temperature of the absorbent in the detoxification liquid circulation reaction tank is controlled to be 40 to 60 °C, so that at least part of the acrolein entering the liquid phase undergoes hydration and / or addition conversion, and the concentration of free acrolein in the liquid phase at the outlet of the detoxification liquid circulation reaction tank is maintained below 10 mg / L.

[0012] Furthermore, in the pre-treatment of detoxification, bisulfite is added to the absorbent according to the concentration of acrolein in the waste gas or absorbent, and the molar ratio of the added bisulfite to acrolein is 0.3:1 to 1.2:1; when the concentration of acrolein in the waste gas experiences a short-term increase or peak impact, the molar ratio is increased to 1.0:1 to 1.5:1.

[0013] Furthermore, the aerobic microbial biofilm is formed by the domestication of aerobic granular sludge, which is taken from the wastewater treatment system that treats the comprehensive wastewater of the industrial park.

[0014] Furthermore, the acclimatization includes: starting culture with methanol as the main substrate until biofilm formation; then introducing the detoxified gas and gradually increasing the acrolein inlet load in a stepwise manner, with each load level being increased to the next level only after the removal efficiency has stabilized; and during the increase process, the concentration of acrolein in the circulating liquid is maintained below 10 mg / L through dilution and / or the front-end detoxification pretreatment.

[0015] Furthermore, the filler is carbon fiber felt or activated carbon fiber felt, and is modified by surface hydrophilic oxidation before use; utilizing the adsorption capacity of the filler, when the acrolein intake concentration reaches a peak, it is adsorbed and temporarily stored by the filler, and when the intake concentration decreases, the adsorbed acrolein is slowly released and degraded by the aerobic microbial biofilm, thereby buffering the peak fluctuations in intake concentration.

[0016] Furthermore, the empty tower residence time of the aerobic biological trickling filter is 45 to 120 s, the pH of the circulating liquid is controlled at 6.5 to 8.0, and nutrients are supplemented to the circulating liquid at a carbon-nitrogen-phosphorus ratio of 100:5:1.

[0017] The present invention has the following beneficial effects:

[0018] (1) In view of the biocidal properties of acrolein, the present invention first consumes the carbon-carbon double bond of acrolein by hydration and addition with bisulfite before biological treatment, thereby weakening its ability to act as a Michael acceptor to add with the sulfhydryl groups of proteins in microorganisms, thereby reducing the toxic load reaching the biofilm. This overcomes the technical prejudice in the field that acrolein is biocidal and therefore biological methods are not used, and enables biological methods to be effectively applied to this type of waste gas.

[0019] (2) Aerobic granular sludge taken from the comprehensive sewage of the park was used and acclimated in a targeted manner by starting with methanol co-metabolism and gradually increasing acrolein, which solved the problem of survival and establishment of degrading microorganisms under biocidal components and shortened the system start-up cycle.

[0020] (3) By using hydrophilically modified carbon fiber felt filler as both a biological carrier and an adsorption medium, the peak concentration of acrolein is adsorbed, temporarily stored, and slowly degraded, thereby improving the system's tolerance to fluctuations in inlet gas concentration.

[0021] (4) Based on the above-mentioned front-end detoxification, targeted domestication and adsorption buffering further improve the system's tolerance to acrolein and its adaptability to fluctuations in inlet gas concentration, enabling the system, which was originally prone to inactivation and collapse due to simple transplantation of conventional biological treatment processes, to be established and operate stably.

[0022] (5) The overall process retains the advantages of low energy consumption of biological methods and avoids secondary air pollution from combustion methods. The waste liquid discharged from the detoxification section can be incorporated into the park's sewage treatment system for disposal. Detailed Implementation

[0023] Various exemplary embodiments of the present invention are now described in detail. Unless otherwise specified, the methods used in the embodiments are conventional methods, and the reagents used are commercially available reagents or reagents prepared using conventional methods. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and embodiments of the present invention.

[0024] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0025] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0026] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0027] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0028] The term "acrylaldehyde-containing waste gas" as used in this article refers to volatile organic waste gas containing acrolein, and optionally also containing components such as allyl alcohol, methanol, and acetaldehyde, typically originating from the polymerization and / or melt spinning processes in the production of polypropylene terephthalate fibers. The term "detoxification" refers to reducing the toxicity of acrolein to microorganisms through chemical transformation, including but not limited to the hydration of acrolein in water to form β-hydroxypropionaldehyde, and the addition of acrolein to bisulfite to form adducts. The term "aerobic granular sludge" refers to a dense microbial aggregate formed under aerobic conditions.

[0029] Example 1

[0030] The waste gas being treated was a simulated waste gas formulation based on actual measured composition of exhaust gas from the polymerization and spinning processes of a PTT fiber production unit, with a treatment volume of approximately 0.3 Nm³. 3 / h, the main components and concentrations are: acrolein 5~100 mg / Nm 3 Allyl alcohol 10-80 mg / Nm 3 Methanol 20-200 mg / Nm 3 Acrolein is a characteristic toxic component of the waste gas. After treatment in a pre-treatment detoxification section, the waste gas enters an aerobic biological trickling filter. The concentration of acrolein in the inlet gas is 0.5, 2, 5, and 10 mg / Nm³, depending on the operating conditions. 3 Fourth gear.

[0031] The aerobic biological trickling filter tower is filled with carbon fiber felt packing material that has undergone surface hydrophilic oxidation modification. The packing volume is 5 L, and the designed empty tower residence time is 60 s. During the initial acclimation stage, the empty tower residence time can be extended to 90-120 s by reducing the treatment air volume. After stable operation, it is gradually restored to the design value. The inoculum is aerobic granular sludge taken from the wastewater treatment plant. Part of it is homogenized and dispersed and sprayed with the circulating liquid to form a biofilm on the packing material. The other part is placed in the circulating liquid tank in granular form as a biomass reserve and shock buffer. Nutrients are added to the circulating liquid at a carbon-nitrogen-phosphorus ratio of approximately 100:5:1, the pH is controlled at 6.5-8.0, and the circulation rate is 20-40 L / h. During operation, the specific oxygen consumption rate and dehydrogenase activity are monitored regularly to characterize biofilm activity.

[0032] The acclimation process was carried out in stages as follows, with the concentration of free acrolein in the circulating solution used as the key control parameter:

[0033] (1) Start-up period: Cultivate with methanol as the main substrate until biofilm is formed and methanol removal rate is stable. The time required is about 7 to 10 days. During this stage, the free acrolein in the circulating liquid is controlled below 0.5 mg / L.

[0034] (2) Acclimation period: The exhaust gas detoxified at the front end is introduced, and the concentration of acrolein entering the tower is increased in stages, with the levels being 0.5, 2, and 5 mg / Nm³ respectively.3 Each step is only advanced to the next step after the removal rate is stable at ≥80% and the biofilm activity index shows no downward trend. During this stage, the free acrolein in the circulating liquid is maintained below 1 mg / L by increasing the circulation volume for dilution and / or strengthening the front-end detoxification.

[0035] (3) Stabilization period: The concentration of acrolein entering the tower is further increased to 10 mg / Nm 3 The free acrolein in the circulating fluid is maintained at 1–2 mg / L; when a peak shock occurs, the free acrolein in the circulating fluid is allowed to rise to below 5 mg / L for a short period without causing biofilm inactivation.

[0036] After approximately 30–45 days of acclimatization, the system achieved stable removal rates of 85%–95% for acrolein, 80%–95% for all alcohols, and 90%–98% for methanol during the stabilization period.

[0037] Example 2

[0038] In the front-end detoxification section of the system described in Example 1, water or an aqueous solution containing bisulfite is used as the absorbent, and the acrolein-containing waste gas and the absorbent are brought into countercurrent contact within the detoxification absorption tower. The liquid-to-gas ratio in the front-end detoxification section is controlled at 2–8 L / Nm³. 3 Preferably 3-5 L / Nm 3 Considering the low boiling point of acrolein and the significant increase in its Henry's constant with increasing temperature, the temperature of the absorbent in the detoxification absorption tower is controlled to be no higher than 35 °C to ensure gas-liquid mass transfer efficiency. After flowing out from the bottom of the tower, the absorbent enters a detoxification liquid circulation reaction tank, where it is heated to 40-60 °C, preferably 45-55 °C, and the residence time is controlled to be 10-60 min, preferably 20-40 min, to allow at least a portion of the acrolein entering the liquid phase to undergo a hydration reaction to generate β-hydroxypropanal, consuming its carbon-carbon double bonds. After the reaction, the absorbent is cooled to below 35 °C and returned to the detoxification absorption tower for recycling. Sodium bisulfite is added to the absorbent based on the concentration of acrolein in the gas phase at the inlet of the detoxification tower and / or the concentration of free acrolein in the absorbent. The molar ratio of sodium bisulfite to acrolein is controlled at 0.3–1.2:1, preferably 0.5–1.0:1. When the concentration of acrolein at the inlet of the detoxification tower experiences a short-term increase or peak impact, the molar ratio can be increased to 1.0–1.5:1 to promote the addition reaction between acrolein and bisulfite to generate a water-soluble adduct, thereby reducing the concentration of free acrolein in the gas and liquid phases.

[0039] In the front-end detoxification section, the pH of the absorbent is controlled at 7.5-9.0, preferably 8.0-8.5, by adding alkaline solution. The added bisulfite contains HSO3 in the water. - With SO3 2- The dissociation equilibrium of sulfurous acid, and the second-order dissociation constant pK.a2 The pH is approximately 7.2; when the pH is higher than this value, the SO3 in the solution... 2- The proportion increased, while SO3 2- Its strong nucleophilicity favors the 1,4-addition of acrolein to the carbon-carbon double bond, forming a sulfonate adduct containing a carbon-sulfur bond. The carbon-sulfur bond in this type of adduct does not dissociate with pH changes; therefore, the resulting adduct will not release acrolein again after entering the circulating liquid of an aerobic biological trickling filter with a pH of 6.5–8.0. Conversely, if the pH of the detoxification section is too low, the reaction will generate more carbonyl adducts of aldehyde and bisulfite (α-hydroxysulfonates). These adducts are prone to dissociation and release of free acrolein at higher pH levels, which is detrimental to maintaining the detoxification effect. Furthermore, weakly alkaline conditions also favor the addition reaction of water to the carbon-carbon double bond of acrolein. However, the pH should not be too high, otherwise it will promote the aldehyde-aldol condensation and polymerization of acrolein, causing an increase in the color of the absorbent and the accumulation of byproducts.

[0040] At the inlet of the detoxification tower, i.e., before detoxification, the concentrations of acrolein in the gas phase were 5, 10, 30, and 100 mg / Nm³. 3 Experiments were conducted under different operating conditions. By adjusting the liquid-to-gas ratio, absorbent residence time, and sodium bisulfite dosage, the concentration of acrolein in the gas phase entering the aerobic biotrickling filter after front-end detoxification could be controlled at approximately 0.5, 2, 5, and 10 mg / Nm³. 3 The corresponding detoxification efficiency is approximately 80%–90%. After treatment, the concentration of acrolein in the gas phase falls within the design concentration range of 0.5–10 mg / Nm³ at the inlet of the aerobic biological trickling filter. 3 Inside.

[0041] Under the above operating conditions, when the biotrickling filter is running stably, the concentration of free acrolein in its circulating liquid can be maintained at 1–2 mg / L. When the concentration of acrolein at the inlet of the detoxification tower experiences short-term peak fluctuations, the concentration of free acrolein in the circulating liquid of the biotrickling filter can be kept below 5 mg / L for short periods by increasing the dosage of sodium bisulfite, increasing the circulation volume of the absorbent, and / or increasing the proportion of circulating liquid discharged. Thus, the front-end detoxification section can reduce the peak concentration of acrolein and decrease its inhibitory effect on the downstream aerobic microbial biofilm.

[0042] Example 3

[0043] To verify the effectiveness of the present invention compared to a simple transplantation of conventional biological treatment processes, a control example and the embodiment of the present invention were set up for parallel operation. Both used inoculated sludge from the same source, the same packing volume, and the same circulating liquid nutrient composition, and the air intake conditions were kept consistent.

[0044] Example for comparison:

[0045] The front-end detoxification section was eliminated, and the acrolein-containing waste gas was directly introduced into an aerobic biological trickling filter inoculated with the same aerobic granular sludge. The steady-state influent acrolein concentration was 30 mg / Nm³. 3 The results showed that the system had a certain removal capacity in the early stage of operation, and the acrolein removal rate could be maintained at 60% to 75%; however, as operation progressed, free acrolein gradually accumulated in the circulating liquid, and the biofilm specific oxygen consumption rate and dehydrogenase activity showed a downward trend.

[0046] When the inlet acrolein concentration experiences a peak surge, i.e., from 30 mg / Nm³... 3 The concentration of the substance rose to 100 mg / Nm3 in a short period of time. 3 Subsequently, the concentration of free acrolein in the circulating liquid rapidly increased, biofilm activity decreased significantly, and the acrolein removal rate dropped rapidly from 60%–75% to below 30%. After the peak shock was stopped and the original steady-state inlet concentration was restored, the system removal rate still failed to recover to the pre-shock level within 7 days, showing obvious instability and difficulty in recovery.

[0047] Embodiments of the present invention:

[0048] Under the same initial inlet air and peak impact conditions, the acrolein-containing waste gas is first treated in a front-end detoxification section before entering the aerobic biotrickling filter. Under steady-state conditions, the concentration of acrolein in the gas phase entering the biotrickling filter is 30 mg / Nm³. 3 Reduced to approximately 5 mg / Nm 3 Under peak impact conditions, the concentration of acrolein in the gas phase entering the biotrickling filter decreased from 100 mg / Nm³. 3 Reduced to approximately 10 mg / Nm 3 .

[0049] The results showed that the concentration of free acrolein in the circulating liquid of the biotrickling filter remained at a low level, ranging from 1 to 2 mg / L during steady-state operation and briefly below 5 mg / L during peak shock. The specific oxygen consumption rate and dehydrogenase activity of the biofilm did not show a sustained decrease. Under the same peak shock conditions, the acrolein removal rate only fluctuated briefly from 90%–95% to 80%–85%, and recovered to the pre-shock level within 12–24 hours. The system did not experience instability or biofilm inactivation, and the overall acrolein removal rate remained stable above 80%.

[0050] The above results indicate that, under conditions of strong biocidal activity of acrolein and peak fluctuations in inlet concentration, conventional aerobic biotrickling filtration alone is insufficient to maintain stable operation. This invention does not simply add an absorption pretreatment unit; rather, it reduces the concentration of free acrolein through front-end detoxification, improves biofilm tolerance through directional acclimation, and achieves adsorption buffering and slow-release degradation through hydrophilic carbon fiber felt packing. The synergistic effect of these three methods allows the system to operate at 100 mg / m³. 3It can recover quickly even under peak impact, demonstrating shock resistance stability that exceeds the expectations of conventional biotrickling filtration processes.

[0051] Example 4

[0052] After the system described in Example 1 entered a stable operating phase, to verify the adsorption and buffering effect of the hydrophilically modified carbon fiber felt packing on acrolein concentration fluctuations, a peak shock of the gaseous acrolein concentration was artificially applied into the tower, i.e., after detoxification. Specifically, the gaseous acrolein concentration entering the aerobic biotrickling filter tower was reduced from 5 mg / Nm³. 3 The step increase was 50 mg / Nm 3 The concentration was maintained for 30 minutes, then reduced to 5 mg / Nm3. 3 .

[0053] The results showed that during the peak impact period, the hydrophilically modified carbon fiber felt packing could adsorb and temporarily store some of the acrolein entering the tower, resulting in a lower rate of increase and peak concentration of acrolein at the outlet of the aerobic biotrickling filter compared to the control system packed with ordinary inert packing. Simultaneously, the instantaneous toxic load entering the biofilm was reduced. During the peak impact period, the concentration of free acrolein in the circulating liquid increased briefly but remained below 5 mg / L, and the specific oxygen consumption rate and dehydrogenase activity of the biofilm did not show a sustained decrease.

[0054] The peak impact ended and the acrolein concentration at the inlet of the tower was restored to 5 mg / Nm³. 3 Subsequently, the acrolein adsorbed on the carbon fiber felt filler gradually desorbs and is released, and further degraded under the action of the circulating liquid and biofilm. With the release and degradation of the adsorbed acrolein, the adsorption sites of the filler are regenerated, enabling it to continue to play an adsorption buffering role in subsequent concentration fluctuations.

[0055] The above results indicate that the hydrophilic modified carbon fiber felt packing not only serves as an attachment carrier for aerobic microbial biofilms, but also exerts a synergistic effect of "adsorption and temporary storage - slow release - biodegradation" when the acrolein inlet concentration increases for a short time, thereby reducing the instantaneous toxic impact of peak concentration on the biofilm and improving the system's shock resistance stability to acrolein concentration fluctuations.

[0056] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A biological treatment method for acrolein-containing waste gas, characterized in that, Includes the following steps: (1) Front-end detoxification pretreatment step: The waste gas is brought into contact with the absorbent liquid, and the peak concentration of acrolein in the waste gas and its toxicity to microorganisms are reduced by means of the hydration reaction of acrolein entering the liquid phase and / or the addition reaction of acrolein with the added bisulfite, so as to obtain the detoxified gas. (2) Aerobic biological trickling filtration step: The detoxified gas is passed into an aerobic biological trickling filter tower equipped with circulating liquid, where the aerobic microbial biofilm loaded on the packing material degrades acrolein and optionally acrylonitrile alcohol and methanol to obtain purified gas.

2. The method according to claim 1, characterized in that, The waste gas is a volatile organic waste gas containing acrolein and accompanied by acrylonitrile alcohol and / or methanol, generated during the polymerization and / or spinning processes in the production of polypropylene terephthalate fiber.

3. The method according to claim 1, characterized in that, In the aforementioned front-end detoxification pretreatment, the pH of the absorbent is controlled to be 7.5 to 9.0, the residence time of the absorbent in the detoxification liquid circulation reaction tank is controlled to be 10 to 60 min, and the temperature of the absorbent in the detoxification liquid circulation reaction tank is controlled to be 40 to 60 °C, so that at least part of the acrolein entering the liquid phase undergoes hydration and / or addition conversion, and the concentration of free acrolein in the liquid phase at the outlet of the detoxification liquid circulation reaction tank is maintained below 10 mg / L.

4. The method according to claim 1, characterized in that, In the aforementioned front-end detoxification pretreatment, bisulfite is added to the absorbent according to the concentration of acrolein in the waste gas or absorbent, and the molar ratio of the added bisulfite to acrolein is 0.3:1 to 1.2:1; when the concentration of acrolein in the waste gas experiences a short-term increase or peak impact, the molar ratio is increased to 1.0:1 to 1.5:

1.

5. The method according to claim 1, characterized in that, The aerobic microbial biofilm is formed by the domestication of aerobic granular sludge, which is taken from the wastewater treatment system that treats the comprehensive wastewater of the industrial park.

6. The method according to claim 5, characterized in that, The acclimatization process includes: initiating culture with methanol as the main substrate until biofilm formation; subsequently introducing the detoxified gas and gradually increasing the acrolein inlet load in a stepwise manner, with each load level being increased to the next level only after the removal efficiency has stabilized; and during the increase process, maintaining the acrolein concentration in the circulating liquid below 10 mg / L through dilution and / or the aforementioned front-end detoxification pretreatment.

7. The method according to claim 1, characterized in that, The filler is carbon fiber felt or activated carbon fiber felt, and its surface is modified by hydrophilic oxidation before use. Utilizing the adsorption capacity of the filler, when the acrolein intake concentration reaches a peak, it is adsorbed and temporarily stored by the filler. When the intake concentration decreases, the adsorbed acrolein is slowly released and degraded by the aerobic microbial biofilm, thereby buffering the peak fluctuations in the intake concentration.

8. The method according to claim 1, characterized in that, The empty tower residence time of the aerobic biological trickling filter is 45 to 120 s, the pH of the circulating liquid is controlled at 6.5 to 8.0, and nutrients are added to the circulating liquid at a carbon-nitrogen-phosphorus ratio of 100:5:1.