An environmental chamber test method for determining VOC adsorption / emission characteristics of flexible porous materials

Abstract

The present invention discloses an environmental chamber testing method for measuring the VOC adsorption / emission characteristics of flexible porous materials. The VOC distribution coefficient K and diffusion coefficient D of a fabric sample are key parameters that determine its adsorption and emission characteristics for indoor VOC gases. The present invention utilizes an environmental chamber to provide a constant temperature and humidity environment, conducts adsorption and emission tests on fabric samples in a closed state, and measures the VOC concentration in the environmental chamber at each stage. By establishing mass conservation equations for different adsorption and emission stages, a correlation formula between the VOC mass transfer characteristic parameters of the fabric sample and the VOC concentration in the environmental chamber is obtained. Combined with the analytical solution of the gas phase VOC concentration, the distribution coefficient K and diffusion coefficient D of the fabric sample VOC are obtained using algebraic calculation and nonlinear fitting. Through this method, the VOC adsorption / emission characteristics of flexible porous materials can be quickly and accurately measured.

Description

Technical Field

[0001] The invention belongs to the field of indoor environmental quality detection, and particularly relates to an environmental chamber testing method for measuring VOC adsorption / emission characteristics of flexible porous materials. Background Art

[0002] Volatile organic compounds (VOCs) are widely present in various indoor decorative materials, such as wood-based panels, and have serious negative impacts on human health. With the booming textile industry, more and more fabrics are being used in interior decoration, leading to a growing demand for fabrics such as sofas, curtains, and carpets. In indoor environments, fabrics like curtains, carpets, and sofas have porous structures and are classified as flexible porous materials due to their softness and deformability. Flexible porous materials have high porosity, large surface area, and high surface roughness, which enhance their ability to adsorb indoor gaseous VOCs. The re-emission of adsorbed VOCs can cause secondary indoor air pollution. Furthermore, flexible porous materials such as clothing and mattresses come into direct contact with the human body, resulting in extensive exposure and prolonged duration. Therefore, flexible porous materials are a key medium for indoor VOC transport and exposure. Understanding the VOC adsorption and emission characteristics of flexible porous materials is crucial for accurately predicting indoor VOC concentrations and developing appropriate control and purification strategies. The distribution coefficient (K) and diffusion coefficient (D) are characteristic parameters of VOC mass transfer in flexible porous materials, which directly affect the VOC adsorption / emission characteristics of flexible porous materials and the indoor VOC pollution distribution.

[0003] Research on experimental methods for measuring VOC emission parameters has been ongoing for decades. For example, fluidized bed desorption and ambient temperature extraction methods are used to determine the initial releasable concentration (C0), while wet cup, double chamber, and microbalance methods are used to determine D and K. However, these methods require complex experimental systems, are time-consuming, suffer from high errors, and can only measure one parameter at a time. To more quickly and accurately measure VOC emission parameters, researchers have proposed multi-equilibrium regression, multiple emission regression, and multi-gas-to-solid ratio methods. While these methods shorten experimental time and can simultaneously measure two emission parameters, they still require separate experiments to measure D. The closed-chamber C-history method and the direct-flow chamber C-history method can simultaneously measure three emission parameters, but they have certain limitations on the choice of experimental data and a complex solution process. The improved C-history method can utilize all experimental data for multi-parameter fitting, but this can result in multiple solutions. These methods still suffer from complex experimental procedures and difficult data analysis and processing, and they all primarily test hard building materials. Rigid building materials typically act as sources in indoor environments, emitting VOCs. Flexible, porous materials, on the other hand, act as both sinks and secondary sources. They not only adsorb VOCs in the indoor environment but also release them into the air when concentrations decrease, prolonging pollution and increasing concentrations. Therefore, existing methods for measuring VOC emission characteristics, primarily targeting rigid building materials, are not applicable to flexible, porous materials.

[0004] Currently, there is limited research on methods for measuring VOC mass transfer parameters for flexible porous materials. Traditional methods for measuring VOC emission parameters for rigid building materials are not fully applicable to flexible porous materials such as fabrics. Therefore, selecting appropriate measurement methods for the VOC adsorption / emission characteristics of flexible porous materials, and thereby accurately determining VOC mass transfer parameters for these materials, remains a leading concern for researchers in this field. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide an environmental chamber testing method for measuring the VOC adsorption / emission characteristics of flexible porous materials. The method can measure the VOC mass transfer characteristic parameters of fiber fabrics of different materials: the distribution coefficient K and the diffusion coefficient D, and is suitable for closed environmental chamber testing.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] An environmental chamber test method for determining VOC adsorption / emission characteristics of flexible porous materials, characterized by comprising the following steps:

[0008] Step 1: Place equal volumes of VOC solutions of the same concentration in a first beaker and a second beaker;

[0009] Step 2: Place the first beaker in a clean, sealed environmental test chamber, maintain constant temperature and humidity, and record the temperature and humidity parameters in the chamber as working condition 1; let the first beaker stand for a sufficient time until the VOC solution in it is completely volatilized and the parameters in the chamber reach equilibrium, and measure the VOC gas equilibrium concentration C in the chamber at this time. equ,1 ;

[0010] Step 3: Open the environmental chamber, remove the first beaker, wipe the inner wall of the environmental chamber with acetone solution, keep the environmental chamber door open and let in clean air until the background VOC concentration is below the detection limit;

[0011] Step 4: Place the fabric sample and the second beaker in a clean, sealed environmental test chamber, maintaining the temperature and humidity in the chamber at Condition 1; allow the second beaker to stand for a sufficient time until the VOC solution in it is completely volatilized and the parameters in the chamber reach equilibrium. At this time, the VOC concentration adsorbed by the fabric sample reaches the equilibrium value, and the VOC gas equilibrium concentration C in the chamber is measured. equ,2 ;

[0012] Step 5: Take out the fabric sample, seal it and store it away from light. Take out the second beaker, wipe the inner wall of the environmental chamber with acetone solution, and introduce clean air into the chamber until the background VOC concentration is lower than the detection limit.

[0013] Step 6: Adjust the temperature and humidity in the chamber to working condition 1, put in the fabric sample, and keep it sealed; let the fabric sample stand for a long enough time to allow the parameters in the chamber to reach equilibrium, and measure the VOC gas phase concentration C in the chamber at this time. a,exp (t i ) and equilibrium concentration C equ,3 ;

[0014] Step 7, calculating the initial VOC emitting concentration C0 and the VOC distribution coefficient K of the fabric sample based on the law of conservation of mass and the relationship between the VOC concentration in the air and solid surface;

[0015] Step 8, C a,exp (t i ) and the theoretical analytical solution of VOC concentration in the closed cabin C a,cal (t i ) nonlinear fitting to obtain the VOC diffusion coefficient D of the fabric sample.

[0016] In one embodiment, the air volume inside the environmental test chamber is 30L, the air temperature control range inside the chamber is 10-40°C, the relative humidity control range is 30%-90%, the temperature accuracy range is ±0.5°C, and the relative humidity accuracy range is ±5%.

[0017] In one embodiment, the wall material of the environmental test chamber is made of stainless steel, and a circulating fan is provided on the top of the chamber to maintain the air flow rate in the chamber at 0.1 to 0.3 m / s, so that the VOC concentration in the air is evenly distributed.

[0018] In one embodiment, the volume of the VOC solution in the first beaker and the second beaker does not exceed 3 mL, and the concentration of the solution is 0.1 mg / mL to 1 mg / mL.

[0019] In one embodiment, the VOC concentration is detected using an online gas analysis mass spectrometer, with a single sampling volume not exceeding 30 mL and a sampling frequency not less than 1 hour each time.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) Based on the adsorption / emission characteristics of flexible porous materials, the present invention develops a closed environmental chamber testing method for the VOC mass transfer characteristic parameters of flexible porous materials, which is suitable for various types of fiber fabrics indoors.

[0022] (2) The environmental chamber test system of the present invention is relatively simple to build, the experimental operation process is clear, the required test parameters are relatively few, and the test cycle is relatively short, which is convenient for practical engineering applications.

[0023] (3) The errors involved in the experimental method of the present invention are easy to control and the experimental accuracy is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a general schematic diagram of the environmental chamber test system and experimental instrument layout of the present invention.

[0025] Figure 2 Schematic diagram of the layout of the environmental chamber in each test stage of the present invention.

[0026] Figure 3 This is a comparative analysis chart of the measured and predicted VOC concentrations emitted by the flexible porous material in the environmental chamber in the embodiment.

[0027] The numbers in the figure represent: 1-environmental test chamber, 101-temperature and humidity control panel, 102-sampling port, 103-flow meter, 104-cabin door, 105-exhaust port, 106-inner cabin, 107-air inlet, 108-circulation fan, 2-fabric sample, 3-wireless temperature and humidity recorder, 4-wind speed sensor, 401-wind speed recorder, 5-thermocouple temperature sensor, 501-thermocouple temperature recorder, 6-beaker, 7-online gas analysis mass spectrometer, 8-computer, 9-stainless steel wire. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0029] The present invention discloses an environmental chamber testing method for measuring the VOC adsorption / emission characteristics of flexible porous materials, which is mainly suitable for closed environmental chambers. The VOC distribution coefficient K and diffusion coefficient D of a fabric sample are key parameters that determine its adsorption and emission characteristics for indoor VOC gases. The present invention utilizes an environmental chamber to provide a constant temperature and humidity environment, conducts adsorption and emission tests on fabric samples in a closed state, and measures the VOC concentration in the environmental chamber at each stage. By establishing mass conservation equations for different adsorption and emission stages, a correlation formula between the VOC mass transfer characteristic parameters of the fabric sample and the VOC concentration in the environmental chamber is obtained. Combined with the analytical solution of the gas phase VOC concentration, the distribution coefficient K and diffusion coefficient D of the fabric sample VOC are obtained using algebraic calculation and nonlinear fitting. Through this method, the VOC adsorption / emission characteristics of flexible porous materials can be quickly and accurately measured.

[0030] like Figure 1 、 Figure 2 As shown, the method of the present invention mainly comprises the following steps:

[0031] Step 1: Prepare two equal volumes and concentrations of VOC solutions in the same beaker, named the first beaker 6 and the second beaker 10, respectively. Seal and store in a dark place for future use. m (m 3 ) is a flexible porous material sample to be tested, named fabric sample 2.

[0032] In the embodiment of the present invention, the volume of the VOC solution in the first beaker 6 and the second beaker 10 does not exceed 3 mL, and the concentration of the solution is 0.1 mg / mL to 1 mg / mL. The fabric sample 2 is pre-treated before the experiment to default to not emit VOC at room temperature.

[0033] In step 2, place the first beaker 6 containing the VOC solution into a clean, sealed environmental test chamber 1. Keep the chamber sealed and turn on the circulation fan 108 to maintain a constant temperature and humidity. The temperature and humidity parameters in the chamber are then recorded using a wireless temperature and humidity recorder 3 and a thermocouple temperature sensor 5. This is referred to as operating condition 1.

[0034] In this embodiment of the present invention, the internal air volume of the environmental test chamber 1 is 30L, and the ratio of the chamber air volume to the volume of the fabric sample 2 to be tested ranges from 100 to 1000. The chamber air temperature is controlled within a range of 10°C to 40°C, and the relative humidity is controlled within a range of 30% to 90%, with a temperature accuracy of ±0.5°C and a relative humidity accuracy of ±5%. The walls of the environmental test chamber 1 are made of stainless steel to minimize any impact on the experimental results. A circulating fan 108 is installed at the top of the chamber to maintain an air velocity of 0.1 to 0.3 m / s, ensuring a uniform distribution of VOC concentrations in the air.

[0035] Step 3: Let the first beaker 6 stand for a sufficient time until the VOC solution therein is completely volatilized and the parameters in the closed environment chamber reach a balanced state. At this time, the VOC gas equilibrium concentration C in the closed environmental test chamber 1 is measured. equ,1 , mg / m 3 . C equ,1 It represents the equilibrium concentration of VOC in the closed environmental chamber after the VOC solution is placed in the closed environmental chamber.

[0036] In the present invention, the VOC concentration is detected by an online gas analysis mass spectrometer 7, the single sampling volume does not exceed 30 mL, and the sampling frequency is not less than 1 hour each time.

[0037] Step 4: Open the environmental test chamber 1, take out the first beaker 6, wipe the inner wall of the chamber with acetone solution, keep the chamber door open and let in clean air until the background VOC concentration is lower than the detection limit.

[0038] Step 5: Place the fabric sample 2 and the second beaker 10 together in a clean and sealed environmental test chamber 1 , close the chamber door to keep it sealed, turn on the chamber circulation fan 108 , and maintain the temperature and humidity in the chamber at working condition 1 .

[0039] Step 6: Let the second beaker 10 stand for a sufficient time until the VOC solution therein is completely volatilized and the parameters in the chamber reach a balanced state. At this time, the concentration of VOC adsorbed by the fabric sample 2 reaches the equilibrium value. The VOC gas equilibrium concentration C in the chamber at this time is measured by the gas online analysis mass spectrometer 7. equ,2 , mg / m 3 . C equ,2 It represents the equilibrium concentration of VOC in the closed environmental chamber after the VOC solution and the fiber fabric sample to be tested are placed in the closed environmental chamber.

[0040] Step 7: Establish the following equation based on the law of conservation of mass:

[0041] C equ.1 V=C equ.2 V+C0V m (12)

[0042]

[0043] Calculate the initial VOC emitting concentration C0 of fabric sample 2, mg / m 3 C0 represents the VOC equilibrium concentration inside the fiber fabric after the VOC solution and the fiber fabric sample to be tested are placed in a closed environmental chamber, that is, the initial emitting concentration. Where V is the volume of air in the environmental chamber, m 3 .

[0044] Step 8: Open the cabin door, remove the fabric sample 2 from the sealed cabin and quickly put it into a sealed bag to protect it from light. Take out the second beaker 10, wipe the inner wall of the environmental cabin with acetone solution, and introduce clean air into the cabin to flush the environmental test cabin until the background VOC concentration is lower than the detection limit.

[0045] Step 9: Adjust the temperature and humidity in the cabin to working condition 1, and quickly take out the fabric sample 2 from the sealed bag and put it into the cabin. Close the cabin door to keep it sealed, and turn on the circulation fan 108.

[0046] Step 10: The fabric sample 2 is left to stand for a sufficient time to allow the parameters in the closed chamber to reach equilibrium. At this time, the hourly gas phase concentration C of VOC in the closed chamber is measured by the online gas analysis mass spectrometer 7. a,exp (t i ) and equilibrium concentration C equ,3 , mg / m 3 . C equ,3 It represents the equilibrium concentration of VOCs in a closed environmental chamber after the VOC-adsorbed fiber fabric is placed in the closed chamber.

[0047] Step 11, according to the law of conservation of mass, establish the equation as follows:

[0048] C0V m -C equ.3 V=C m V m (14)

[0049] Where C m is the VOC concentration inside the fiber fabric, mg / m 3 .

[0050] According to the relationship between VOC concentration on gas-solid surface, the following equation can be further derived:

[0051] C0V m -C equ.3 V=KC equ.3 V m (15)

[0052]

[0053] By solving the equation, the initial VOC emitting concentration C0 and the VOC distribution coefficient K of fabric sample 2 are calculated; where V is the volume of air in the cabin; V m is the volume of fabric sample 2. Substituting the experimental test data into formula (2) and formula (5) to obtain the initial emanable concentration C0 and distribution coefficient K of the fiber fabric sample.

[0054] Step 12: measure the real-time emission concentration of the fabric sample 2 in the closed environment chamber C a,exp (ti ) and the theoretical analytical solution of VOC concentration in the closed cabin C a,cal (t i ) nonlinear fitting to obtain the VOC diffusion coefficient D of fabric sample 2.

[0055] Complete analytical solution for VOC concentration in closed environmental test chamber 1 a,cal (t i )as follows:

[0056]

[0057]

[0058] A n =(Kβ-q n 2 KBi m -1 +1)cos q n -(1+2KBi m -1 )q n sin q n (19)

[0059] Bi m =h m L / D (20)

[0060] Where: β is defined as the material / air volume ratio, and its calculation formula is β=V m / V;

[0061] C a,cal (t i )——VOC concentration in the closed environment chamber, mg / m 3 ;

[0062] L——half the thickness of fabric sample 2, m;

[0063] D——Diffusion coefficient of fabric sample 2, m 2 / s;

[0064] t i ——Durability of emission, s;

[0065] i——gas sampling times;

[0066] q n ——is the positive root of formula (7), n is a natural number starting from 1;

[0067] h m ——Convective mass transfer coefficient, m / s;

[0068] Bi m——Mass transfer Biot number.

[0069] In step 13, the obtained distribution coefficient K and the initial dispersible concentration C0 are substituted into formula (6). In formula (6), only the diffusion coefficient D is unknown. Therefore, the diffusion coefficient D is nonlinearly fitted using the improved relative least squares method. The calculation formula η of the concentration curve fitting error is as follows:

[0070]

[0071]

[0072]

[0073] Where: J Di ——normalized relative sensitivity coefficient of VOC concentration of the i-th sampling to D;

[0074] w Di ——When D is the only variable, t i The weight of concentration data at time;

[0075] η——fitting error;

[0076] M——the total number of samples in step 6;

[0077] ε——the amplitude of change of D.

[0078] By adjusting the value of the diffusion coefficient D and performing nonlinear fitting using formula (10), the diffusion coefficient D of fabric sample 2 can be determined when the η value is the minimum.

[0079] In a more specific embodiment of the present invention, the formaldehyde emission characteristic parameters of the fabric are measured, and the specifications of the fabric sample 2 are 405mm×205mm×0.6mm (length×width×thickness), and the ratio of the volume of the fabric sample 2 to the volume of the air in the cabin (i.e., the solid-gas ratio) is β=1 / 602. The formaldehyde concentration is calibrated with distilled water to 0.1mg / mL, and 1mL of the formaldehyde aqueous solution is taken each time and placed in a beaker as an emission source. The sampling frequency of the online gas analysis system is set to 15min / time, and the single gas sampling volume is 10mL. During the experiment, the temperature of the environmental chamber is set to 23℃, and the relative humidity is controlled at 50±5%. The fabric sample is subjected to 5 closed environmental chamber adsorption tests, and the corresponding C equ,1 、C equ,2 and C equ,3 Already in Figure 2 Displayed in.

[0080] See also Figure 1 The emission test of the fabric sample to be tested in the present invention is carried out in an environmental chamber. The main experimental equipment includes:

[0081] (1) Environmental test chamber 1, the air volume of the inner chamber 106 is 30L, and the temperature and humidity of the air in the chamber are adjusted by the temperature and humidity control panel 101, with a control temperature range of 10-40℃, a relative humidity range of 30%-90%, a temperature accuracy range of ±0.5℃, and a relative humidity accuracy range of ±5%. The gas in the chamber can be sampled and analyzed through the sampling port 102, where a flow meter 103 can be set. This test only uses the closed mode of the environmental chamber. In the closed state, the air inlet 107 and the exhaust port 105 are both closed. The wall material of the inner chamber 106 is stainless steel that is inert and non-adsorbent to VOCs, and the gap of the door 104 is sealed with a non-adsorbent sealing strip. A circulating fan 108 is installed on the top of the chamber to ensure that the air flow rate in the chamber is 0.1 to 0.3m / s, so that the VOC concentration in the air is evenly distributed. The fabric sample 2 is suspended in the middle of the environmental chamber by a stainless steel wire 9, and the direction of gas flow is parallel to the surface of the fabric sample 2.

[0082] (2) Temperature and humidity recording system, including wireless measurement sensor 3 for air temperature and humidity in the cabin, thermocouple temperature sensor 5 for recording the wall temperature in the environmental cabin, and thermocouple temperature recorder 501.

[0083] (3) A wind speed sensor 4 for measuring the wind speed on the surface of the fabric sample 2 and a recorder 401 connected thereto.

[0084] (4) VOC gas composition and concentration analysis system: When measuring single or mixed VOC gases, the mixed gas in the chamber is sampled through the sampling port 102, and then qualitative and quantitative analysis is performed through the online gas analyzer 7. Finally, all sampled data are stored and processed and analyzed by the computer 8.

[0085] See also Figure 1 as well as Figure 2 In (a), (b), (c), and (d), when the experiment begins, the VOC solution emission test is first conducted in a sealed state. A certain temperature and humidity are set, and the temperature and humidity conditions at this time are recorded as Condition 1.

[0086] Place the beaker 1 containing the pre-made formaldehyde solution into the environmental chamber, close the door, close the air inlet 107 and the exhaust port 105, and place the experimental supplies in the environmental chamber as shown below. Figure 2 (a). Let beaker 1 stand for a sufficient period of time and use an online gas analysis system to monitor the VOC concentration in the environmental chamber in real time. The gas sampling frequency is 15 minutes per time and the gas sampling volume is 3 mL. When the average formaldehyde concentration changes by no more than 1% within one hour, the gas phase formaldehyde concentration in the environmental chamber is considered to have reached equilibrium. The equilibrium concentration value of the online mass spectrometry gas analysis system at this time is recorded, which is 3.09 mg / m 3 , which is C equ,1 .

[0087] Open the door, take out beaker 1, and exhaust the VOC gas in the chamber to return the environmental chamber to a clean state. At this time, the experimental supplies in the environmental chamber are placed as follows: Figure 2 Middle (d).

[0088] After the environmental chamber is restored to a clean state, the second beaker 10 containing the pre-made formaldehyde solution is placed in the environmental chamber, and the fabric sample 2 is placed on the stainless steel wire in the center of the environmental chamber. Close the door, adjust the temperature and humidity parameters in the environmental chamber to working condition 1, and then place the experimental supplies in the environmental chamber as shown below. Figure 2 (b) The second beaker 10 and the fabric sample 2 were allowed to stand for a sufficient period of time, and the equilibrium formaldehyde concentration in the chamber was measured and recorded by an online mass spectrometry gas analysis system. The value was 1.241 mg / m 3 , which is C equ,2 According to formula (2), the initial radiable concentration C0 is 1113 mg / m 3 , open the door, put the fabric sample 2 into a sealed bag, and take it out. Keep the door open, exhaust the VOC gas in the chamber, and return the environmental chamber to a clean state. At this time, the experimental supplies in the environmental chamber are placed as follows Figure 2 Middle (d).

[0089] After the environmental chamber returns to a clean state, take out the fabric sample 2 from the sealed bag and quickly re-place it on the stainless steel wire in the middle of the environmental chamber. Adjust the temperature and humidity parameters in the environmental chamber to working condition 1. At this time, the experimental supplies in the environmental chamber are placed as follows: Figure 2 (c) Close the door of the environmental chamber, close the air inlet 107 and the exhaust port 105. Use the online gas analysis system to monitor the VOC concentration in the environmental chamber in real time and record the hourly formaldehyde gas phase concentration C in the chamber. a,exp (t i ) and equilibrium concentration C equ,3 , C equ,3 The value is 0.733 mg / m 3 .

[0090] According to formula (5), the VOC distribution coefficient K of the fiber fabric sample is obtained, and its value is 917. At this time, the initial volatile concentration C0 and the distribution coefficient K are both known. When the error η is minimized, D is output, and its value is 4.02×10 -12 m 2 / s.

[0091] In summary, the K, D and C0 of the tested fiber fabric samples can be obtained from the experiment, which are 917, 4.02×10 -12 m 2 / s and 1113.52 mg / m 3 Substitute the experimental values ​​of K, D and C0 of the fiber fabric sample into formula (6) to calculate C a,cal (t i) and compared with the experimental value C a,exp (t i ) for comparison, the results are as follows Figure 3 The relative errors of the two are less than 10% throughout the entire emission period, and the errors show a decreasing trend as the emission time increases, which proves the accuracy of this experimental method.

[0092] The environmental chamber test method for determining the VOC adsorption / emission characteristics of flexible porous materials proposed in the present invention has a simple principle, a convenient and fast data processing process, and high-precision parameter measurement results, which is suitable for engineering promotion and application.

Claims

1. An environmental chamber test method for determining the VOC adsorption / emission characteristics of flexible porous materials, characterized in that: The steps include: Step 1: Place equal volumes of VOC solutions of the same concentration in a first beaker (6) and a second beaker (10); Step 2: Place the first beaker (6) in a clean and sealed environmental test chamber (1), maintain constant temperature and humidity in the chamber, and record the temperature and humidity parameters in the chamber at this time as working condition 1; let the first beaker (6) stand for a sufficient time until the VOC solution therein is completely volatilized and the various parameters in the chamber reach a balanced state, and measure the VOC gas equilibrium concentration C in the chamber at this time. equ,1 ; Step 3: open the environmental chamber, take out the first beaker (6), wipe the inner wall of the environmental chamber with acetone solution, keep the environmental chamber door open and let in clean air until the background VOC concentration is lower than the detection limit; Step 4: Place the fabric sample (2) and the second beaker (10) together in a clean and sealed environmental test chamber (1), and maintain the temperature and humidity in the chamber to working condition 1; let the second beaker (10) stand for a sufficient time until the VOC solution therein is completely volatilized and the various parameters in the chamber reach a balanced state. At this time, the VOC concentration adsorbed by the fabric sample (2) reaches the equilibrium value, and the VOC gas equilibrium concentration C in the chamber is measured. equ,2 ; Step 5: Take out the fabric sample (2), seal it and store it away from light, take out the second beaker (10), wipe the inner wall of the environmental chamber with acetone solution, and introduce clean air into the chamber until the background VOC concentration is lower than the detection limit; Step 6: Adjust the temperature and humidity in the chamber to working condition 1, put the fabric sample (2) in, and keep it sealed; let the fabric sample (2) stand for a sufficient time to allow the parameters in the chamber to reach a balanced state, and measure the VOC gas phase concentration C in the chamber at this time. a,exp (t i ) and equilibrium concentration C equ,3 ; Step 7, calculating the VOC initial emitting concentration C0 and the VOC partition coefficient K of the fabric sample (2) according to the law of conservation of mass and the relationship between the VOC concentration of the gas-solid surface; Step 8, C a,exp (t i ) and the theoretical analytical solution of VOC concentration in the closed cabin C a,cal (t i ) nonlinear fitting to obtain the VOC diffusion coefficient D of fabric sample (2); Among them, the theoretical analytical solution C a,cal (t i )as follows: A n \(Kβ-q n 2 KBi m -1 +1)cosq n -(1+2KBi m -1 )q n five n (3) Ball m h m L / D (4) Where: β is the material / air volume ratio, and its calculation formula is β=V m / V, V is the volume of air in the cabin; V m is the volume of the fabric sample (2); q n is the positive root of formula (2), n is a natural number starting from 1; L is half the thickness of the fabric sample (2); t i is the time for the fabric sample (2) to emit in step 6, i is the number of gas sampling times; Bi m is the mass transfer Biot number; h m is the convective mass transfer coefficient; Substituting K and C0 into formula (1), the diffusion coefficient D is nonlinearly fitted using the improved relative least squares method. The calculation formula of the concentration curve fitting error η is as follows: Where: J Di is the normalized relative sensitivity coefficient of the VOC concentration of the i-th sampling to D; w Di When D is the only variable, t i The weight of the concentration data of time; η is the fitting error; M is the total number of sampling times in step 6; ε is the variation range of D. By adjusting the value of the diffusion coefficient D, nonlinear fitting is performed using formula (5). When the η value is the minimum, the diffusion coefficient D of the fabric sample (2) can be determined.

2. The environmental chamber test method for determining VOC adsorption / emission characteristics of flexible porous materials according to claim 1, characterized in that: The internal air volume of the environmental test chamber (1) is 30L, the air temperature control range in the chamber is 10-40°C, the relative humidity control range is 30%-90%, the temperature accuracy range is ±0.5°C, and the relative humidity accuracy range is ±5%.

3. The environmental chamber test method for determining VOC adsorption / emission characteristics of flexible porous materials according to claim 1, characterized in that: The wall material of the environmental test chamber (1) is made of stainless steel, and a circulating fan (108) is provided on the top of the chamber to maintain the air flow rate in the chamber at 0.1 to 0.3 m / s, so that the VOC concentration in the air is evenly distributed.

4. The environmental chamber test method for determining VOC adsorption / emission characteristics of flexible porous materials according to claim 1, characterized in that: The volume of the VOC solution in the first beaker (6) and the second beaker (10) does not exceed 3 mL, and the concentration of the solution is 0.1 mg / mL to 1 mg / mL.

5. The environmental chamber test method for determining VOC adsorption / emission characteristics of flexible porous materials according to claim 1, characterized in that: The VOC concentration is detected by an online gas analysis mass spectrometer (7), with a single sampling volume not exceeding 30 mL and a sampling frequency not less than 1 hour each time.

6. The environmental chamber test method for determining VOC adsorption / emission characteristics of flexible porous materials according to claim 1, characterized in that: In step 7, the following equation is established based on the law of conservation of mass and the relationship between VOC concentration on the gas-solid surface: C equ.1 V=C equ.2 V+C0V m (8) C0V m -C equ.3 V=KC equ.3 V m (10) By solving the equation, the initial VOC emitting concentration C0 and the VOC distribution coefficient K of the fabric sample (2) are calculated.

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