Absorbent for reversibly capturing co2 in industrial flue gas at ambient temperature and its preparation method and application

Abstract

This invention discloses an absorbent for reversibly capturing industrial flue gas at room temperature, its preparation method, and its application. The absorbent of this invention comprises, by mass percentage: 1%-10% sodium ricinoleate, 2.5%-10% triethanolamine, 1%-5% potassium lysine, and 70%-96% water. The "sodium ricinoleate-triethanolamine-potassium lysine" composite absorbent constructed in this invention achieves most of the desorption at room temperature and pressure by introducing nitrogen gas or exposing it to air, with a desorption rate of 81%. Compared with pure sodium ricinoleate absorbent, it increases the absorption capacity for pure sodium ricinoleate by 2.45 times and the absorption capacity for simulated flue gas by 4.5 times. After eight carbon dioxide absorption-desorption cycles, the regeneration efficiency reaches over 70%, exhibiting good cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of gas separation technology, specifically relating to a method for reversibly capturing industrial flue gas at room temperature. Absorbents, their preparation methods, and applications. Background Technology

[0002] The continued growth of global carbon dioxide emissions has led to severe environmental problems such as the intensified greenhouse effect and abnormal climate change. Carbon capture, utilization, and storage (CFS) technologies are considered key pathways to achieving carbon neutrality, with carbon dioxide capture being the fundamental step, and its cost directly impacting the economic viability of subsequent utilization. Among existing capture technologies, post-combustion capture is the most widely used due to its broad applicability and ease of modification, with chemical absorption being the most mature post-combustion capture technology to date.

[0003] The key to chemical absorption methods lies in the absorbent. Primary / secondary amine absorbents widely used in industry (such as monoethanolamine (MEA), diethanolamine (DEA), etc.) have the ability to absorb... While possessing advantages such as high reactivity and large absorption capacity, it also suffers from drawbacks including high regeneration energy consumption (typically requiring heating to 100-120℃ for desorption), easy oxidative degradation, strong corrosiveness to equipment, and high volatility, potentially causing secondary pollution. In contrast, tertiary amines are more basic and theoretically possess higher reactivity. It has capture potential, but because its nitrogen atom does not contain active hydrogen, it cannot directly interact with... The reaction does not occur, but rather catalyzes water and... The reaction produces bicarbonate and protonated amine. The absorption products formed by tertiary amines have low stability; introducing nitrogen at room temperature reduces their stability. Deprotonation can be achieved by partial pressure, causing bicarbonate ions to decompose and be released. This allows for gentle regeneration. While amino acid salt absorbents offer advantages such as rapid absorption, low volatility, and environmental friendliness, their absorption capacity is limited and their cost is high, making it difficult to meet the demand for efficient capture when used alone.

[0004] Our team's previous research (patent publication number: CN114644535A) has revealed that natural fatty acid salt absorbents, represented by sodium ricinoleate, possess significant advantages such as being naturally sourced, renewable, and environmentally friendly. More importantly, their absorption... The saturated sodium ricinoleate aqueous solution can be completely desorbed at room temperature by passing nitrogen gas through it or by direct exposure to air, avoiding the high-temperature regeneration energy consumption of traditional absorbents. However, this absorbent still has limitations such as limited absorption capacity and slow absorption rate, which restricts its large-scale application.

[0005] To address the aforementioned problems, this invention enables reversible operation at room temperature. This invention focuses on the absorption / desorption of sodium ricinoleate, utilizing the complementary properties of different absorbents to construct a "sodium ricinoleate-tertiary amine-amino acid salt" complex system: the high absorption capacity of the alkanolamine compensates for the limited absorption capacity and slow rate of sodium ricinoleate, while the high absorption rate of the amino acid salt improves the absorption kinetics of sodium ricinoleate, and the unique advantage of reversible desorption at room temperature is retained. This synergistic effect of the three components upgrades the performance of the sodium ricinoleate absorbent. Furthermore, the captured carbon dioxide can be used as a gaseous fertilizer for greenhouse plant cultivation, promoting photosynthesis and increasing crop yield, forming a low-carbon closed loop of "industrial capture - agricultural application". The absorbent provided by this invention combines excellent absorption performance with room temperature desorption characteristics, is environmentally friendly, and can be directly applied to plant foliar sprays, offering convenient operation and providing an integrated solution for industrial flue gas carbon dioxide capture and agricultural resource utilization. Summary of the Invention

[0006] The purpose of this invention is to provide a method for reversibly capturing industrial flue gas at room temperature. Absorbent.

[0007] Another objective of this invention is to provide a method for reversibly capturing industrial flue gas at room temperature. Preparation method of absorbent.

[0008] Another objective of this invention is to provide a method for reversibly capturing industrial flue gas at room temperature. The application of absorbents.

[0009] This invention is achieved through the following technical solution: The present invention describes a reversible industrial flue gas capture method at room temperature. The absorbent formulation, by weight percentage, includes: sodium ricinoleate 1%-10%, triethanolamine 2.5%-10%, potassium lysine 1%-5%, and water 70%-96%.

[0010] Preferably, the formulation of the present invention comprises: 3-7% sodium ricinoleate, 2.5-7.5% triethanolamine, 1-4% potassium lysine, and 80-93.5% water.

[0011] More preferably, the formulation of the present invention comprises: 5-6% sodium ricinoleate, 2.5-5% triethanolamine, 2-3% potassium lysine, and 86-90.5% water.

[0012] More preferably, the formulation of the present invention comprises: 6% sodium ricinoleate, 5% triethanolamine, 2% potassium lysine, and 87% water.

[0013] The purity of the absorbent described in this invention The absorption capacity was 27.2 mg / g, the desorption capacity was 22 mg / g, and the desorption rate was 81%; the absorption capacity for simulated flue gas was 15.9 mg / g, and the desorption capacity was 10.1 mg / g.

[0014] The preparation method of the absorbent of the present invention is as follows: sodium ricinoleate, triethanolamine, and potassium lysine are weighed according to the formula ratio, and then water of the formula amount is added. After thorough mixing and ultrasonic dispersion, the absorbent is obtained.

[0015] The ultrasonic dispersion time described in the preparation method of this invention is 10-40 min.

[0016] Preferably, the ultrasonic dispersion time in the preparation method of the present invention is 15-20 min.

[0017] More preferably, the ultrasonic dispersion time in the preparation method of the present invention is 15 min.

[0018] The absorbent described in this invention can reversibly capture and release industrial flue gas at room temperature and pressure. Applications.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The ternary compound absorbent of sodium ricinoleate-triethanolamine-potassium lysine constructed in this invention can achieve most of its absorption under normal temperature and pressure conditions simply by introducing nitrogen gas or exposing it to air. The desorption rate reached 81%. This ternary compound absorbent underwent 8 cycles of desorption. It can still maintain a high level after the absorption-desorption cycle. Absorption capacity and regeneration efficiency remain above 70%, with good cycle stability. This is in contrast to processes requiring high temperatures. Compared to traditional chemical absorbents for desorption (such as monoethanolamine solutions), the absorbent of this invention requires no heating under mild conditions; it only needs to be cooled. The partial pressure can be spontaneously released through a reverse reaction. Specifically, sodium ricinoleate chemically absorbs [the following information] at room temperature. The formation of ricinoleic acid and sodium bicarbonate, and the absorption of triethanolamine. Then protonated triethanolamine and bicarbonate are formed; the two absorption products mentioned above are at low... It can spontaneously deprotonate and release energy under partial pressure conditions. .

[0020] 2. Compared with pure sodium ricinoleate (NaRI) absorbent, the ternary compound absorbent described in this invention has… The absorption performance is significantly improved, especially for pure... The absorption capacity increased by 2.45 times, and the absorption capacity for simulated flue gas increased by 4.5 times. Pure NaRI absorbent showed a 2.45-fold increase in absorption capacity compared to pure... The absorption and desorption capacities were both 7.88 mg / g. The pure absorbent of the ternary compound absorbent (NaRI / TEA / Lysk) was... The absorption capacity increased to 27.2 mg / g, and the desorption capacity increased to 22.0 mg / g. Under simulated flue gas conditions, the absorption capacity and desorption capacity of pure NaRI absorbent were both 2.88 mg / g, while the absorption capacity of the ternary compound absorbent increased to 15.9 mg / g, and the desorption capacity increased to 10.1 mg / g.

[0021] 3. The ternary compound absorbent described in this invention can be used as a carbon dioxide fertilizer to promote plant growth. Pot experiments and plant physiological tests showed that, compared with the blank control group, treatment with the ternary compound absorbent (including NaRI / TEA / Lysk+) significantly improved plant growth. Burley tobacco grown with NaRI / TEA / Lysk+ simulated flue gas showed improvements in multiple growth indicators: plant height, stem diameter, root length, number of leaves, maximum leaf length and width, total leaf area, fresh weight, and dry weight all increased. Simultaneously, leaf SPAD (chlorophyll) values ​​and leaf periphery values ​​also improved. Concentration and intercellular The concentration also increased, the content of malondialdehyde (MDA) in leaves decreased, the photosynthetic rate increased, while the transpiration rate and stomatal conductance showed a decreasing trend, and the water use efficiency was significantly enhanced. Attached Figure Description

[0022] Figure 1 Carbon dioxide absorption (a), desorption (b), and desorption rate (c) at room temperature of the sodium ricinoleate and primary / secondary amine complex absorption system; carbon dioxide absorption (d), desorption (e), and desorption rate (f) at room temperature of the sodium ricinoleate and tertiary amine complex absorption system (where the curves in c and f represent the desorption rate). Figure 2 The effects of changing the proportion of triethanolamine on the carbon dioxide absorption (a) and desorption amount (b) and desorption rate (c) of the binary compound absorption system at room temperature, and the effects of changing the proportion of sodium ricinoleate on the carbon dioxide absorption (d) and desorption amount (e) and desorption rate (f) of the absorption system at room temperature (where the curves in c and f represent the desorption rate). Figure 3. Comparison of carbon dioxide absorption capacity of various amino acid salt absorbents at 0.5 mol / L; Figure 4 Carbon dioxide absorption (a), desorption (b), and desorption rate (c) of a binary absorbent (NaRI / TEA) compounded with potassium lysine of different mass fractions (where the curve in c represents the desorption rate). Figure 5Carbon dioxide absorption and desorption capacity of individual components and compound systems of absorbents; Figure 6 The absorption (a) and desorption (b) performance of ternary (NaRI / TEA / Lysk) absorbent and pure NaRI absorbent on pure carbon dioxide and simulated flue gas; Figure 7 Cyclic absorption stability test of ternary compound absorbent (where the bar chart represents carbon dioxide absorption and the broken line represents regeneration efficiency). Figure 8 Photos of plants after multiple applications of different fertilizers (where a is the 4th application, b is the 8th application, c is the 12th application, d is the 16th application; e, f, and g are front views of the plants after the 16th application, and h is a root system diagram of the plants after the 16th application). Figure 9 Effects of different fertilizers on the phenotypic traits of Burley tobacco (where a is chlorophyll (SPAD) content; b is plant height; c is number of leaves; d is stem diameter; e is maximum leaf length; f is maximum leaf width; g is root length; h is total leaf area; and i is total soluble sugar content). Figure 10 Effects of different fertilizers on the phenotypic traits of Burley tobacco (where a is malondialdehyde content; b is fresh weight of aboveground and underground parts; c is dry weight of aboveground and underground parts; d is carbon dioxide concentration around leaves; e is intercellular carbon dioxide concentration; f is net photosynthetic rate; g is transpiration rate; h is stomatal conductance; i is water use efficiency). Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0024] Example 1: Reversible capture of industrial flue gas at room temperature absorbent formulation 6% sodium ricinoleate, 5% triethanolamine, 2% potassium lysine, 87% water.

[0025] Example 2: Reversible capture of industrial flue gas at room temperature absorbent formulation 1% sodium ricinoleate, 10% triethanolamine, 5% potassium lysine, 84% water.

[0026] Example 3: Reversible capture of industrial flue gas at room temperature absorbent formulation 10% sodium ricinoleate, 2.5% triethanolamine, 1% potassium lysine, 86.5% water.

[0027] Example 4: Reversible capture of industrial flue gas at room temperature absorbent formulation 6% sodium ricinoleate, 7.5% triethanolamine, 3% potassium lysine, 83.5% water.

[0028] Example 5: Reversible capture of industrial flue gas at room temperature absorbent formulation 5% sodium ricinoleate, 2.5% triethanolamine, 3% potassium lysine, 89.5% water.

[0029] Example 6: Reversible capture of industrial flue gas at room temperature absorbent formulation 7% sodium ricinoleate, 5% triethanolamine, 2% potassium lysine, 86% water.

[0030] The formulations of Examples 1-6 were used in the following preparation methods. Example 7 Reversible capture of industrial flue gas at room temperature Method for preparing absorbent Weigh out sodium ricinoleate, triethanolamine, and potassium lysine according to the formula ratio, add the formula amount of water, mix thoroughly and ultrasonically disperse for 15 minutes to obtain the absorbent.

[0031] Example 8: Reversible capture of industrial flue gas at room temperature Absorbent preparation method Weigh out sodium ricinoleate, triethanolamine, and potassium lysine according to the formula ratio, add the formula amount of water, mix thoroughly and ultrasonically disperse for 40 minutes to obtain the absorbent.

[0032] Example 9: Reversible capture of industrial flue gas at room temperature Absorbent preparation method Weigh out sodium ricinoleate, triethanolamine, and potassium lysine according to the formula ratio, add the formula amount of water, mix thoroughly and ultrasonically disperse for 10 minutes to obtain the absorbent.

[0033] Example 10 Reversible capture of industrial flue gas at room temperature Method for preparing absorbent Weigh out sodium ricinoleate, triethanolamine, and potassium lysine according to the formula ratio, add the formula amount of water, mix thoroughly and ultrasonically disperse for 20 minutes to obtain the absorbent.

[0034] To verify the effectiveness of the invention, the inventive team conducted a series of experiments, as follows: I. Experimental Reagents Sodium ricinoleate (NARI, ≥93%), monoethanolamine (MEA, AR), diethanolamine (DEA, AR), piperazine (PZ, ≥99%), 2-amino-2-methyl-1-propanol (AMP, ≥95%), tetraethylenepentamine (TEPA, industrial grade), triethanolamine (TEA, AR), N-methyldiethanolamine (MDEA, ≥98%), diethylaminoethanol (DEEA, ≥99%), N,N,N,N,N-pentamethyldivinyltriamine (PMDETA, ≥99%), 2-dimethylamino-2-methylpropanol (DMAMP, ≥97%), L-lysine (Lys, ≥98%), glycine (Gly, ≥99%), β-alanine (Ala, ≥99%), L-glutamic acid (Glu, ≥99%), and potassium hydroxide (KOH, AR) were all purchased from Aladdin Reagent Co., Ltd. All amino acid salts were prepared by reacting the corresponding amino acids with potassium hydroxide (KOH) in molar amounts. The amino acid salt solutions were prepared using deionized water.

[0035] II. Experimental Methods 1. Formulation Investigation Experiment (1) Construction and screening of binary composite absorbents A 10g (w / w) 5% sodium ricinoleate aqueous solution was used as the base absorbent and mixed with five primary / secondary amines (MEA, DEA, PZ, AMP, TEPA) and five tertiary amines (TEA, MDEA, DEEA, PMDETA, DMAMP) by mass to construct binary complex systems. The absorbance of each system at room temperature was measured. By analyzing absorption and desorption rates, amine components with optimal absorption and desorption performance are selected.

[0036] (2) Optimization of the proportions of each component in the binary absorption system With a fixed sodium ricinoleate mass fraction of 5%, triethanolamine with mass fractions of 2.5%, 5%, and 7.5% was added respectively. The carbon dioxide absorption and desorption under nitrogen gas at room temperature were measured to determine the mass fraction of triethanolamine in the compound.

[0037] With a fixed triethanolamine mass fraction of 5%, sodium ricinoleate was added at mass fractions of 5%, 6%, and 7%, respectively. The carbon dioxide absorption and desorption under nitrogen at room temperature were measured to determine the optimal compound ratio of NaRI and TEA.

[0038] (3) Construction and screening of ternary compound absorbents The properties of 10g of 0.5mol / L aqueous solutions of four amino acid salts (potassium lysine, potassium glycine, potassium glutamate, and potassium alanine) were determined. Absorption performance was assessed to select the optimal amino acid salt absorbent.

[0039] Potassium lysine was combined with the above-mentioned optimal binary absorbent to form a ternary compound. The mass fraction of potassium lysine added was adjusted (1%, 2%, 3%), and the absorption and desorption performance of each ratio was measured to determine the optimal compound ratio of the ternary absorbent.

[0040] 2. Absorbent Preparation Method Taking the preparation of a ternary compound absorbent with a mass ratio of 10g sodium ricinoleate:triethanolamine:potassium lysine of 6:5:2 as an example, 0.6g sodium ricinoleate, 0.5g triethanolamine, and 0.2g potassium lysine were weighed according to the ratio and added to a 50ml colorimetric tube. Then, 8.7g water was added, and the mixture was thoroughly mixed and ultrasonically dispersed for 15min to obtain the absorbent.

[0041] 3. Pure Absorption performance test method The absorption temperature is 25°C, and the absorption pressure is one standard atmosphere. The gas volume fraction is 99.999%, controlled by a gas mass flow controller. The flow rate was 25 ml / min. 10 g of the corresponding absorbent was prepared according to the previously described absorbent preparation method. The absorbent was placed in a bubbling absorption bottle, and the bottle was sealed with a rubber stopper and two needles. One needle was inserted into the solution, and the other needle was placed above the liquid surface, connected to the surrounding environment. A syringe tubing filled with cotton was added to prevent liquid loss. The bottle with the rubber stopper and syringe tubing was weighed to obtain the mass. 25ml / min of pure Bubbling is performed into the absorbent. The absorption bottle, including the rubber stopper and syringe tubing, is weighed every 5 minutes until the total weight of the bubbling absorption bottle stops increasing and remains constant for 15 minutes. At this point, the solution is saturated, and the total weight of the absorption bottle is recorded. The increase in the total weight of the absorption bottle. That is, absorption by the absorbent. The weight.

[0042] 4. Method for determining the absorption performance of simulated flue gas The absorption temperature is 25°C, the absorption pressure is one standard atmosphere, and pure... He Chun Preparation of simulated flue gas (20%) +80% ), controlled by a gas mass flow controller The flow rate is 10 ml / min. The flow rate was 40 ml / min. After mixing the two thoroughly, a simulated flue gas was bubbled into the absorption bottle. 10 g of the corresponding absorbent was prepared according to the previously described absorbent preparation method. The absorbent was placed in the bubbling absorption bottle, and the bottle was sealed with a rubber stopper and two needles. One needle was inserted into the solution, and the other needle was placed above the liquid surface, connected to the surrounding environment. A syringe tube filled with cotton was added to prevent liquid loss. The bottle with the rubber stopper and syringe tube was weighed to obtain the mass. Simulated flue gas was bubbled into the absorbent at a rate of 50 ml / min. The absorbent bottle, equipped with a rubber stopper and syringe tubing, was weighed every 5 minutes until the total weight of the bubbling absorbent bottle stopped increasing and remained so for 15 minutes. At this point, the solution was saturated, and the total weight of the absorbent bottle was recorded. The increase in the total weight of the absorption bottle. This refers to the mass of simulated flue gas absorbed by the absorbent.

[0043] 5. Desorption performance test method The desorption temperature was 25°C, the desorption pressure was one standard atmosphere, and the absorption purity was measured by weight. A small vial containing a rubber stopper and a syringe tube was obtained after simulating flue gas saturation. The flow rate is 10 ml / min Bubbling absorbent is added, and the absorption bottle with rubber stopper and syringe tubing is weighed every 1 hour until the total weight of the bubbling absorption bottle no longer decreases and remains constant for 2 hours. At this point, the solution is completely desorbed, and the total weight of the absorption bottle is recorded. The reduction in the total weight of the absorption bottle. That is, absorbent The quality of desorption.

[0044] 6. Pot experiments and plant physiological tests A standardized pot experiment was conducted at the College of Chemistry and Chemical Engineering, Shihezi University, Xinjiang, China, using *Tobacco Burleyi* as the model plant. Polyethylene pots (20 cm in diameter, 25 cm in height) were used, filled with a peat moss-vermiculite-perlite composite substrate (volume ratio 2:1:1), with a pot weight of 1.5 kg. Seeds were sterilized before sowing and cultured in an artificial climate chamber with a photoperiod of 14 h / 10 h (LED light source 300 MHz). The temperature was 25±0.5℃, and the humidity was 65±5%. Seedlings were transplanted at the two-cotyledon stage, and Hoagland nutrient solution was applied alternately weekly. Three treatment groups were set up: a blank control (CK), a ternary compound absorbent + pure... Ternary compound absorbent + simulated flue gas (20%) +80% Each group contained 5 biological replicates. Treatment began 7 days after seedling transplantation. At 11:00 a.m., a handheld sprayer (pressure 0.2 MPa) containing carbon dioxide gas fertilizer was used to atomize and spray the leaves on both sides. One spray was applied and no repeats were made. The spraying interval was 48 hours, and a total of 16 treatments were performed.

[0045] (1) Measurement of carbon dioxide concentration and photosynthetic parameters around the leaves A portable gas exchange analyzer was used to measure the carbon dioxide concentration around the leaves and photosynthetic parameters. Gas exchange settings were configured. Concentration of 400 The gas flow rate is 500 Photosynthetically active radiation (PAR) remained at 1800 RH set to 50%-70%, Fan Speed ​​set to 10,000 rpm; after fertilization, from 10:00 to 18:00, under room temperature light, using a leaf chamber (ensuring the plant leaves completely fill the leaf chamber), clip the sensor onto the plant leaf. After successful instrument pairing, record the carbon dioxide concentration around the leaf and intercellular density. Indicators such as concentration, net photosynthetic rate, transpiration rate, and stomatal conductance were measured three times and the average value was taken.

[0046] (2) Chlorophyll content determination The chlorophyll content of the leaves was measured after the 4th, 8th, 12th, and 16th fertilizations. The chlorophyll content of the marked leaves was measured directly using a Japanese SPAD-502 plus chlorophyll meter, and the average value was taken from three measurements.

[0047] (3) Agronomic trait determination Agronomic indicators of the plant were measured after the 4th, 8th, 12th, and 16th fertilizations, as follows: Leaf count: Starting with the first fully unfolded leaf at the base of the plant, count each leaf until the first partially unfolded leaf near the terminal bud, and record the total number of leaves; Plant height: Measure the plant height vertically from the ground at the base to the highest point of the terminal bud using a measuring tape, and record the plant height; Stem diameter: Measure the stem circumference diameter of the main stem approximately 5 cm above the ground using calipers, and record the stem circumference diameter; Maximum leaf length and width: Select the largest intact leaf from the upper part of the plant as the measurement object, and use a ruler to measure the longest length (from the leaf base to the leaf tip) and the widest width (measured at the midpoint of the longest part of the leaf), and record the leaf length and width values. During measurement, ensure the leaf is in a naturally unfolded state, avoiding artificial stretching or twisting of the leaf. Each indicator was measured three times, and the average value was taken as the final result.

[0048] (4) Measurement of leaf area of ​​potted plants Lay the plant leaves horizontally on a horizontal surface, and place a 1 on the plane. A square piece of cotton leaf was photographed vertically with a camera to obtain high-resolution images of the cotton leaf and the square piece. The images were then processed using Photoshop to obtain the pixel count of the leaf and the pixel count per unit area. Finally, the formula was applied: A = (Number of pixels per leaf / Number of pixels per unit area) × Area of ​​a standard square; The actual area of ​​the leaf can then be calculated by taking the average of three measurements.

[0049] (5) Determination of fresh and dry weight of plants After the final fertilization, the plants were dug up along with their roots, washed, and their surface moisture was dried. The fresh weight of the above-ground and underground parts was measured separately using an analytical balance. The above-ground and underground parts of the plants were placed separately in large envelopes using the drying method and placed in an oven (electric heating forced-air drying oven) at 105℃ for 1 hour to kill the greening. Then, the oven temperature was set to 70℃ and maintained for 48 hours until constant weight was achieved. The above-ground and underground parts were then removed and their dry weight was measured.

[0050] (6) Determination of soluble sugar content This study used the issone-sulfuric acid method to determine the non-structural carbohydrate (NSC) content of plants. The specific steps are as follows: First, 0.2 g of corn powder sample was weighed into a 50 mL centrifuge tube, and the extraction was performed three times using a boiling water bath. Each time, 10 mL of distilled water was added, and the mixture was extracted in a 95℃ constant temperature water bath shaker for 30 min. During extraction, the mixture was manually shaken every 5 min to ensure complete extraction. The supernatants from the three extractions were combined and the volume was adjusted to 250 mL. Then, 1 mL of the supernatant was mixed with 5 mL of issone reagent (100 mg of issone dissolved in 80%). Mix thoroughly and use a water bath for precise temperature control. After developing the color in a boiling water bath for 10 minutes, immediately terminate the reaction using an ice water bath. Finally, measure the absorbance at 620 nm using a UV-1750 spectrophotometer (Shimadzu, Japan). Calculate the soluble sugar content using a glucose standard curve.

[0051] (7) Determination of malondialdehyde content The malondialdehyde (MDA) content in leaf and root tissues of each treatment was determined using a plant malondialdehyde (MDA) content test kit. The specific measurement procedure was performed according to the kit instructions: Weigh 0.1 g of *Salix babylonica* leaf and root tissues, add 1 mL of extraction buffer, and homogenize in an ice bath. Centrifuge at 8000 g, 4℃ for 10 min, collect the supernatant, and place on ice for testing. Pipette 0.3 mL of reagent I into a 1.5 mL centrifuge tube, add 0.1 mL of sample, and mix well. Incubate in a 95℃ water bath for 30 min, cool in an ice bath, and centrifuge at 10000 g, 25℃ for 10 min. Pipette 200 μL of the supernatant into a 96-well plate and measure the absorbance at 532 nm and 600 nm.

[0052] The calculation formula is as follows: ; ; W: Fresh weight of sample (g); Absorbance at 532 nm; Absorbance at 600nm.

[0053] III. Experimental Results 1. Results of the formulation investigation experiment (1) Construction and screening results of binary composite absorbents See results Figure 1 .Depend on Figure 1 As shown in (a)(b)(c), when sodium ricinoleate is compounded with different primary / secondary amines in equal mass ratios, the carbon dioxide absorption capacity is increased, but the desorption rate is low, all below 60%. Figure 1 (d), (e), and (f) show the effects of blending sodium ricinoleate with different tertiary amines in equal mass ratios. While increasing the carbon dioxide absorption capacity, the desorption rates of these blends were all higher than those of the sodium ricinoleate blend with primary / secondary amines. The blend with sodium ricinoleate and triethanolamine exhibited the highest desorption rate, with a carbon dioxide absorption capacity of 19.4 mg / g and a desorption rate of 85.7%. Therefore, triethanolamine (TEA) was selected as the amine component with the best absorption and desorption performance.

[0054] (2) Optimization results of the proportions of each component in the binary absorption system The results are as follows Figure 2 .Depend on Figure 2 As shown in (a)(b)(c), the carbon dioxide absorption increases with the increase of the triethanolamine blending ratio, but its desorption rate gradually decreases. At a ratio of 1:1.5, the carbon dioxide desorption rate is only 74.5%, while at a ratio of NaRI:TEA=1:1, the carbon dioxide absorption is high (19.4 mg / g) and the desorption rate reaches 85.7%, indicating a high degree of reversibility in the absorption and desorption of carbon dioxide. Therefore, the mass fraction of triethanolamine in the blending is determined to be 5%.

[0055] Depend on Figure 2 As shown in (d)(e)(f), with the increase of the compound ratio of sodium ricinoleate, the carbon dioxide absorption of the binary absorbent first increases and then decreases, while the desorption rate remains basically unchanged. The carbon dioxide absorption is optimal (20.6 mg / g) when NaRI:TEA = 6:5, and the desorption rate is 84.5%. Therefore, the optimal compound ratio of NaRI and TEA is determined to be 6:5.

[0056] The optimal ratio of the binary compound absorbent was determined to be sodium ricinoleate: triethanolamine: water = 6:5:89.

[0057] (3) Construction and screening results of ternary compound absorbent The screening results of amino acid salt absorbents are shown in Figure 3 .Depend on Figure 3 It can be seen that potassium lysine (Lysk) has a higher carbon dioxide absorption capacity (39.5 mg / g) than potassium glycine (Glyk), potassium alanine (Alak), and potassium glutamate (Gluk). Therefore, potassium lysine was selected as the optimal amino acid salt absorbent.

[0058] The results of the investigation into the optimal compound ratio of ternary absorbents are as follows: Figure 4 As the mass fraction of potassium lysine in the ternary compound absorbent increases, the carbon dioxide absorption capacity also increases, but the desorption rate gradually decreases. When 3 wt% potassium lysine is added, the desorption rate is 75.9%, while when 2 wt% is added, the desorption rate reaches 81%. This ensures a high carbon dioxide absorption capacity while maintaining a desorption rate above 80%. Therefore, the optimal compounding ratio of the ternary absorbent, NaRI:TEA:Lysk, was determined to be 6:5:2.

[0059] Depend on Figure 5 It can be seen that the carbon dioxide absorption and desorption capacity of the ternary compound system (NaRI / TEA / Lysk) is higher than that of the binary compound system (NaRI / TEA) and the single component NaRI, TEA and Lysk absorbents. Compared with pure sodium ricinoleate absorbent, the ternary compound system can improve the carbon dioxide absorption capacity while still maintaining a high desorption rate at room temperature.

[0060] The optimal ratio of the ternary compound absorbent was determined to be NaRI:TEA:Lysk:water = 6:5:2:87.

[0061] 2. The effects of ternary absorbents and pure NaRI absorbents on pure NaRI. and the absorption and desorption performance of simulated flue gas The measurement results are as follows Figure 6 The figure shows that the pure ternary (NaRI / TEA / Lysk) absorbent... Compared with pure NaRI absorbent, the absorption capacity increased from 7.88 mg / g to 27.2 mg / g, the desorption capacity increased from 7.88 mg / g to 22 mg / g, the absorption capacity for simulated flue gas increased from 2.88 mg / g to 15.9 mg / g, and the desorption capacity increased from 2.88 mg / g to 10.1 mg / g.

[0062] 3. Cyclic absorption stability test of ternary compound absorbent The measurement results are as follows Figure 7 .Depend on Figure 7 It can be seen that the ternary compound absorbent still maintains a high carbon dioxide absorption capacity after 8 carbon dioxide absorption and desorption cycles, with a regeneration efficiency of over 70%, indicating that the absorption system has good cycle stability.

[0063] 4. Results of pot experiment and plant physiological tests Photos of plants after applying different fertilizers, such as Figure 8 .Depend on Figure 8 It can be seen that the plants treated with fertilizers (A) and (B) grew better than the blank control group (C), specifically in that their leaves were larger, their plant height was greater, and their roots were longer.

[0064] Depend on Figure 9 It can be seen that when applying a ternary compound absorbent (NaRI / TEA / Lysk+), After 16 cycles of treatment with (NaRI / TEA / Lysk + simulated flue gas), the SPAD value increased by 15.7% and 10%, respectively; plant height increased by 34.2% and 18.4%, respectively; stem diameter increased by 18.6% and 8.5%, respectively; and root length increased by 44.7% and 21%, respectively. The number of leaves, maximum leaf length and width, total leaf area, and fresh and dry weight also showed varying degrees of improvement compared to the blank control group, demonstrating that the ternary compound absorbent effectively absorbs pure flue gas. When combined with simulated flue gas, it can be used as a carbon dioxide gas fertilizer to effectively promote plant growth.

[0065] Depend on Figure 10 It can be seen that the application of a ternary compound absorbent (NaRI / TEA / Lysk + After treatment with NaRI / TEA / Lysk + simulated flue gas, the malondialdehyde (MDA) content in Burley tobacco leaves decreased, while the fresh and dry weights of both the above-ground and below-ground parts increased. Specifically, the content around the leaves... The concentration was increased from 420 ppm to 690 ppm and 600 ppm respectively, and the intercellular... The concentrations were increased from 160 ppm to 320 ppm and 250 ppm, respectively. The increased concentration effectively promoted the increase of plant photosynthetic rate, while the transpiration rate and stomatal conductance decreased, resulting in a significant enhancement of water use efficiency.

[0066] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for reversibly capturing industrial flue gas at room temperature The absorbent, characterized in that, By weight percentage, it includes: sodium ricinoleate 1%-10%, triethanolamine 2.5%-10%, potassium lysine 1%-5%, and water 70%-96%.

2. The reversible industrial flue gas capture method at room temperature according to claim 1 The absorbent, characterized in that, By weight percentage, it includes: 3-7% sodium ricinoleate, 2.5-7.5% triethanolamine, 1-4% potassium lysine, and 80-93.5% water.

3. The reversible industrial flue gas capture method at room temperature according to claim 2 The absorbent, characterized in that, By weight percentage, it includes: 5-6% sodium ricinoleate, 2.5-5% triethanolamine, 2-3% potassium lysine, and 86-90.5% water.

4. The reversible industrial flue gas capture method at room temperature according to claim 3 The absorbent, characterized in that, By weight percentage, it includes: 6% sodium ricinoleate, 5% triethanolamine, 2% potassium lysine, and 87% water.

5. The reversible industrial flue gas capture method at room temperature according to claim 4 The absorbent, characterized in that, The purity of the absorbent The absorption capacity was 27.2 mg / g, the desorption capacity was 22 mg / g, and the desorption rate was 81%; the absorption capacity for simulated flue gas was 15.9 mg / g, and the desorption capacity was 10.1 mg / g.

6. A method for preparing the absorbent as described in claims 1-5, characterized in that, The preparation method is as follows: Sodium ricinoleate, triethanolamine, and potassium lysine are weighed according to the formula ratio, and then water of the formula amount is added. After thorough mixing and ultrasonic dispersion, the absorbent is obtained.

7. The method for preparing the absorbent according to claim 6, characterized in that, The ultrasonic dispersion time is 10-40 min.

8. The method for preparing the absorbent according to claim 7, characterized in that, The ultrasonic dispersion time is 15-20 min.

9. The method for preparing the absorbent according to claim 8, characterized in that, The ultrasonic dispersion time is 15 minutes.

10. An absorbent as described in claims 1-5 that reversibly captures and releases industrial flue gas at room temperature and pressure. Applications.

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