Preparation method for nanocomposite fiber membrane material based on bio-based liquefied formaldehyde resin

Abstract

A preparation method for a nanocomposite fiber membrane material based on a bio-based liquefied formaldehyde resin is provided. A bio-based raw material is processed through a phenol/polyethylene glycol complex liquefaction process, followed by divalent alkali metal hydroxide high ortho-position induction synthesis resinification and modification with the polymer polyvinyl alcohol to create a spinnable precursor as PVA-BLF. Subsequently, a coaxial electrospinning device is utilized, where PVA-BLF serves as a core layer and a titanium dioxide dispersion is used as a shell layer, to fabricate a PVA-BLF/TiO.sub.2 nanocomposite fiber membrane material. The average diameter of the nanocomposite fiber membrane is 150-450 nm, and the specific surface area is 500-700 m.sup.2/g. The porosity exceeds 60%, and the fracture elongation ranges from 5.5% to 6.5%, demonstrating excellent filtration performance and excellent regeneration performance, which can be developed as adsorption materials for water and air purification.

Claims

1. A preparation method for a nanocomposite fiber membrane material based on a bio-based liquefied formaldehyde resin, comprising: mixing a bio-based raw material, phenol, and polyethylene glycol in a mass ratio of 1:(1-2):(0.5-1) to obtain a first mixture, adding an acid as a catalyzer to the first mixture to react at a temperature in a range of 120-150 C. for 0.5-2 hours (h) to obtain a reacted mixture, then adding a sodium hydroxide solution to the reacted mixture to adjust a potential of hydrogen (pH) to be 7 to thereby obtain a second mixture, followed by cooling down the second mixture at a temperature in a range of 30-40 C. to obtain a bio-based liquefied product; mixing the bio-based liquefied product, the sodium hydroxide solution, a divalent alkali metal hydroxide, and a formaldehyde solution in a mass ratio of 1:(0.1-0.3):(0.1-0.5):(0.8-1.3) to obtain a mixed solution, heating up the mixed solution to 75-90 C. to react for 30-90 minutes (min) to obtain a reacted solution, and cooling down the reacted solution below 40 C. to obtain the bio-based liquefied formaldehyde resin (BLF); stirring an aqueous solution of the BLF and an aqueous solution of polyvinyl alcohol (PVA) evenly to react at 50-60 C. for 30-60 min to obtain a reacted BLF-PVA solution, then cooling down the reacted BLF-PVA solution to below 30 C. to obtain a BLF-PVA spinning solution as a precursor for coaxial electrospinning; using the BLF-PVA spinning solution as a core layer and a nano titanium dioxide (TiO.sub.2) aqueous dispersion as a shell layer, and using a coaxial nozzle for the coaxial electrospinning to obtain an initial spun fiber film; and drying the initial spun fiber film at a temperature of 130 C. for 5-15 min to cure and shape, thereby obtaining the nanocomposite fiber membrane material of PVA-BLF/TiO.sub.2 with a special secondary structure; wherein a concentration of the sodium hydroxide solution is 40%, and a concentration of the formaldehyde solution is 37%.

2. The preparation method for the nanocomposite fiber membrane material based on the bio-based liquefied formaldehyde resin as claimed in claim 1, wherein the bio-based raw material is one selected from the group consisting of wood powder, shell powder of peanut, shell powder of Juglans regia, and bamboo powder.

3. The preparation method for the nanocomposite fiber membrane material based on the bio-based liquefied formaldehyde resin as claimed in claim 1, wherein the acid is one of an inorganic acid and an organic acid, and the one of the inorganic acid and the organic acid is one selected from the group consisting of sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, and oxalic acid.

4. The preparation method for the nanocomposite fiber membrane material based on the bio-based liquefied formaldehyde resin as claimed in claim 1, wherein the divalent alkali metal hydroxide is one selected from the group consisting of calcium hydroxide, zinc hydroxide, barium hydroxide, and magnesium hydroxide.

5. The preparation method for the nanocomposite fiber membrane material based on the bio-based liquefied formaldehyde resin as claimed in claim 1, wherein a dry matter content of the aqueous solution of the BLF is 10%, a concentration of the aqueous solution of the PVA is 10%, and the PVA is a medium degree of polymerization polymer; wherein the aqueous solution of the PVA is prepared as follows: adding the PVA into water to swell at a room temperature for 5-10 h, thereby obtaining a swelling solution, and followed by reacting the swelling solution at 90 C. for 0.5-2 h to obtain the aqueous solution of the PVA.

6. The preparation method for the nanocomposite fiber membrane material based on the bio-based liquefied formaldehyde resin as claimed in claim 1, wherein process parameters of the coaxial electrospinning comprise: a voltage of 15-22 kilovolts (kV), a shell thrust velocity of 0.5-3 milliliters per hour (mL/h), a core thrust velocity of 0.3-1 mL/h, a distance between a needle and a receiver of 10-30 centimeters (cm), a speed of a receiving drum of 80-200 revolutions per minute (r/min), an ambient temperature controlled at 25-35 C., and a humidity of 20-40%, wherein the receiver wrapped in release paper is used.

7. The preparation method for the nanocomposite fiber membrane material based on the bio-based liquefied formaldehyde resin as claimed in claim 1, wherein the nano TiO.sub.2 aqueous dispersion is prepared as follows: mixing powder of the TiO.sub.2, deionized water, and sodium dodecylbenzene sulfonate in a weight ratio of 10:100:0.1 to obtain a mixed TiO.sub.2 solution, and followed by treating the mixed TiO.sub.2 solution with a low-power ultrasound for 2 h to prepare the nano TiO.sub.2 aqueous dispersion with a concentration of 10%.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 illustrates a scanning electron microscope (SEM) diagram of a nanocomposite fiber membrane in embodiment 1 of the disclosure.

(2) FIG. 2 illustrates an SEM diagram of a nanocomposite fiber membrane in embodiment 2 of the disclosure.

(3) FIG. 3 illustrates an SEM diagram of a nanocomposite fiber membrane in embodiment 3 of the disclosure.

(4) FIG. 4 illustrates an SEM diagram of a nanocomposite fiber membrane in embodiment 4 of the disclosure.

(5) FIG. 5 illustrates an SEM diagram of a nanocomposite fiber membrane in embodiment 5 of the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

(6) The following will further explain the disclosure in conjunction with embodiments of the disclosure. The following embodiments are only intended to provide a clearer explanation of the technical solution of the disclosure and cannot be used to limit the scope of protection of the disclosure.

Embodiment 1

(7) A preparation method for a nanocomposite fiber membrane material based on bio-based liquefied formaldehyde resin includes steps as follows.

(8) Step 1, a bio-based raw material, phenol, and polyethylene glycol are mixed in a mass ratio of 1:1:0.5 to obtain a first mixture, an acid as a catalyzer is added into the first mixture to react at 150 C. for 45 minutes (min) to obtain a reacted mixture, then a sodium hydroxide solution is added into the reacted mixture to adjust a potential of hydrogen (pH) to be 7 (i.e. to neutral) thereby to obtain a second mixture, followed by cooling down the second mixture at 40 C. to obtain a bio-based liquefied product.

(9) Step 2, the bio-based liquefied product, the sodium hydroxide solution, a divalent alkali metal hydroxide, and a formaldehyde solution are mixed in a mass ratio of 1:0.2:0.2:1 to obtain a mixed solution, the mixed solution is heated up to 80 C. to react for 50 min to obtain a reacted solution, and followed by cooling down the reacted solution below 40 C. to obtain the bio-based liquefied formaldehyde resin (BLF).

(10) Step 3, an aqueous solution of the BLF and an aqueous solution of polyvinyl alcohol (PVA) are stirred evenly to react at 50 C. for 30 min to obtain a reacted BLF-PVA solution, then the reacted BLF-PVA solution is cooled down to below 30 C. to obtain a BLF-PVA spinning solution as a precursor for coaxial electrospinning.

(11) Step 4, the BLF-PVA spinning solution is used as a core layer and a nano titanium dioxide (TiO.sub.2) aqueous dispersion is used as a shell layer, and a coaxial nozzle is used for the coaxial electrospinning to obtain an initial spun fiber film.

(12) Step 5, the initial spun fiber film is dried at 130 C. for 10 min to cure and shape, thereby obtaining the nanocomposite fiber membrane material of PVA-BLF/TiO.sub.2 with a special secondary structure. An SEM diagram of a nanocomposite fiber membrane is shown in FIG. 1.

(13) The bio-based raw material is shell powder of peanut, the acid is formic acid, the divalent alkali metal hydroxide is barium hydroxide (Ba(OH).sub.2), a concentration of the sodium hydroxide solution is 40%, and a concentration of the formaldehyde solution is 37%.

(14) A dry matter content of the aqueous solution of the BLF is 10%, a concentration of the aqueous solution of the PVA is 10%, and the PVA is a medium degree of polymerization polymer. A preparation for the solution of the PVA is as follows. The PVA is added into water to swell at a normal temperature (i.e., room temperature) for 8 hours (h), thereby obtaining a swelling solution, and followed by reacting the swelling solution at 90 C. for 2 h to obtain the aqueous solution of the PVA.

(15) Process parameters of the coaxial electrospinning includes a voltage of 15 kilovolts (kV), a shell thrust velocity of 1.5 milliliters per hour (mL/h), a core thrust velocity of 0.3 mL/h, a distance between a needle and a receiver of 18 centimeters (cm), a speed of the receiving drum of 200 revolutions per minute (r/min), an ambient temperature controlled at 25-35 C. and a humidity of 20-40%, the receiver wrapped in release paper is used.

(16) A preparation for the nano TiO.sub.2 aqueous dispersion is as follows: powder of the TiO.sub.2, deionized water, and sodium dodecylbenzene sulfonate are mixed in a weight ratio of 10:100:0.1 to obtain a mixed TiO.sub.2 solution, and followed by treating the mixed TiO.sub.2 solution with a low-power ultrasound for 2 h to prepare the nano TiO.sub.2 aqueous dispersion with a concentration of 10%.

Embodiment 2

(17) A preparation method for a nanocomposite fiber membrane material based on bio-based liquefied formaldehyde resin includes steps as follows.

(18) Step 1, a bio-based raw material, phenol, and polyethylene glycol are mixed in a mass ratio of 1:2:1 to obtain a first mixture, an acid as a catalyzer is added into the first mixture to react at a 130 C. for 90 min to obtain a reacted mixture, then a sodium hydroxide solution is added into the reacted mixture to adjust a pH to be 7 thereby to obtain a second mixture, followed by cooling down the second mixture at 40 C. to obtain a bio-based liquefied product.

(19) Step 2, the bio-based liquefied product, the sodium hydroxide solution, a divalent alkali metal hydroxide, and a formaldehyde solution are mixed in a mass ratio of 1:0.3:0.2:1.2 to obtain a mixed solution, the mixed solution is heated up to 85 C. to react for 45 min to obtain a reacted solution, and followed by cooling down the reacted solution below 40 C. to obtain the BLF.

(20) Step 3, an aqueous solution of the BLF and an aqueous solution of PVA are stirred evenly to react at 55 C. for 40 min to obtain a reacted BLF-PVA solution, then the reacted BLF-PVA solution is cooled down to below 30 C. to obtain a BLF-PVA spinning solution as a precursor for coaxial electrospinning.

(21) Step 4, the BLF-PVA spinning solution is used as a core layer and a nano TiO.sub.2 aqueous dispersion is used as a shell layer, and a coaxial nozzle is used for the coaxial electrospinning to obtain an initial spun fiber film.

(22) Step 5, the initial spun fiber film is dried at 130 C. for 15 min to cure and shape, thereby obtaining the nanocomposite fiber membrane material of PVA-BLF/TiO.sub.2 with a special secondary structure. An SEM diagram of a nanocomposite fiber membrane is shown in FIG. 2.

(23) The bio-based raw material is shell powder of peanut, the acid is hydrochloric acid, the divalent alkali metal hydroxide is zinc hydroxide (Zn(OH).sub.2), a concentration of the sodium hydroxide solution is 40%, and a concentration of the formaldehyde solution is 37%.

(24) A dry matter content of the aqueous solution of the BLF is 10%, a concentration of the aqueous solution of the PVA is 10%, and the PVA is a medium degree of polymerization polymer. A preparation for the solution of the PVA is as follows. The PVA is added into water to swell at a normal temperature for 8 h, thereby obtaining a swelling solution, and followed by reacting the swelling solution at 90 C. for 2 h to obtain the solution of the PVA.

(25) Process parameters of the coaxial electrospinning includes a voltage of 18 kV, a shell thrust velocity of 1.8 mL/h, a core thrust velocity of 0.5 mL/h, a distance between a needle and a receiver of 15 cm, a speed of the receiving drum of 150 r/min, an ambient temperature controlled at 25-35 C. and a humidity of 20-40%, the receiver wrapped in release paper is used.

(26) A preparation for the nano TiO.sub.2 aqueous dispersion is as follows: powder of the TiO.sub.2, deionized water, and sodium dodecylbenzene sulfonate are mixed in a weight ratio of 10:100:0.1 to obtain a mixed TiO.sub.2 solution, and followed by treating the mixed TiO.sub.2 solution with a low-power ultrasound for 2 h to prepare the nano TiO.sub.2 aqueous dispersion with a concentration of 10%.

Embodiment 3

(27) A preparation method for a nanocomposite fiber membrane material based on bio-based liquefied formaldehyde resin includes steps as follows.

(28) Step 1, a bio-based raw material, phenol, and polyethylene glycol are mixed in a mass ratio of 1:2:1 to obtain a first mixture, an acid as a catalyzer is added into the first mixture to react at 120 C. for 60 min to obtain a reacted mixture, then a sodium hydroxide solution is added into the reacted mixture to adjust a pH to be 7 thereby to obtain a second mixture, followed by cooling down the second mixture at 40 C. to obtain a bio-based liquefied product.

(29) Step 2, the bio-based liquefied product, the sodium hydroxide solution, a divalent alkali metal hydroxide, and a formaldehyde solution are mixed in a mass ratio of 1:0.3:0.3:1.2 to obtain a mixed solution, the mixed solution is heated up to 75 C. to react for 60 min to obtain a reacted solution, and followed by cooling down the reacted solution below 40 C. to obtain the BLF.

(30) Step 3, an aqueous solution of the BLF and an aqueous solution of PVA are stirred evenly to react at 60 C. for 50 min to obtain a reacted BLF-PVA solution, then the reacted BLF-PVA solution is cooled down to below 30 C. to obtain a BLF-PVA spinning solution as a precursor for coaxial electrospinning.

(31) Step 4, the BLF-PVA spinning solution is used as a core layer and a nano TiO.sub.2 aqueous dispersion is used as a shell layer, and a coaxial nozzle is used for the coaxial electrospinning to obtain an initial spun fiber film.

(32) Step 5, the initial spun fiber film is dried at 130 C. for 10 min to cure and shape, thereby obtaining the nanocomposite fiber membrane material of PVA-BLF/TiO.sub.2 with a special secondary structure. An SEM diagram of a nanocomposite fiber membrane is shown in FIG. 3.

(33) The bio-based raw material is poplar powder, the acid is sulfuric acid, the divalent alkali metal hydroxide is calcium hydroxide (Ca(OH).sub.2), a concentration of the sodium hydroxide solution is 40%, and a concentration of the formaldehyde solution is 37%.

(34) A dry matter content of the aqueous solution of the BLF is 10%, a concentration of the aqueous solution of the PVA is 10%, and the PVA is a medium degree of polymerization polymer. A preparation for the solution of the PVA is as follows. The PVA is added into water to swell at a normal temperature for 8 h, thereby obtaining a swelling solution, and followed by reacting the swelling solution at 90 C. for 2 h to obtain the solution of the PVA.

(35) Process parameters of the coaxial electrospinning includes a voltage of 20 kV, a shell thrust velocity of 2 mL/h, a core thrust velocity of 0.4 mL/h, a distance between a needle and a receiver of 10 cm, a speed of the receiving drum of 300 r/min, an ambient temperature controlled at 25-35 C. and a humidity of 20-40%, the receiver wrapped in release paper is used.

(36) A preparation for the nano TiO.sub.2 aqueous dispersion is as follows: powder of the TiO.sub.2, deionized water, and sodium dodecylbenzene sulfonate are mixed in a weight ratio of 10:100:0.1 to obtain a mixed TiO.sub.2 solution, and followed by treating the mixed TiO.sub.2 solution with a low-power ultrasound for 2 h to prepare the nano TiO.sub.2 aqueous dispersion with a concentration of 10%.

Embodiment 4

(37) A preparation method for a nanocomposite fiber membrane material based on bio-based liquefied formaldehyde resin includes steps as follows.

(38) Step 1, a bio-based raw material, phenol, and polyethylene glycol are mixed in a mass ratio of 1:2:0.5 to obtain a first mixture, an acid as a catalyzer is added into the first mixture to react at 150 C. for 80 min to obtain a reacted mixture, then a sodium hydroxide is added into the reacted mixture to adjust a pH to be 7 thereby to obtain a second mixture, followed by cooling down the second mixture at 40 C. to obtain a bio-based liquefied product.

(39) Step 2, the bio-based liquefied product, the sodium hydroxide solution, a divalent alkali metal hydroxide, and a formaldehyde solution are mixed in a mass ratio of 1:0.3:0.4:1.3 to obtain a mixed solution, the mixed solution is heated up to 90 C. to react for 30 min to obtain a reacted solution, and followed by cooling down the reacted solution below 40 C. to obtain the BLF.

(40) Step 3, an aqueous solution of the BLF and an aqueous solution of PVA are stirred evenly to react at 60 C. for 40 min to obtain a reacted BLF-PVA solution, then the reacted BLF-PVA solution is cooled down to below 30 C. to obtain a BLF-PVA spinning solution as a precursor for coaxial electrospinning.

(41) Step 4, the BLF-PVA spinning solution is used as a core layer and a nano TiO.sub.2 aqueous dispersion is used as a shell layer, and a coaxial nozzle is used for the coaxial electrospinning to obtain an initial spun fiber film.

(42) Step 5, the initial spun fiber film is dried at 130 C. for 15 min to cure and shape, thereby obtaining the nanocomposite fiber membrane material of PVA-BLF/TiO.sub.2 with a special secondary structure. An SEM diagram of a nanocomposite fiber membrane is shown in FIG. 4.

(43) The bio-based raw material is shell powder of Juglans regia, the acid is oxalic acid, the divalent alkali metal hydroxide is Zn(OH).sub.2, a concentration of the sodium hydroxide solution is 40%, and a concentration of the formaldehyde solution is 37%.

(44) A dry matter content of the aqueous solution of the BLF is 10%, a concentration of the aqueous solution of the PVA is 10%, and the PVA is a medium degree of polymerization polymer. A preparation for the solution of the PVA is as follows. The PVA is added into water to swell at a normal temperature for 8 h, thereby obtaining a swelling solution, and followed by reacting the swelling solution at 90 C. for 2 h to obtain the solution of the PVA.

(45) Process parameters of the coaxial electrospinning includes a voltage of 12 kV, a shell thrust velocity of 2.2 mL/h, a core thrust velocity of 0.6 mL/h, a distance between a needle and a receiver of 20 cm, a speed of the receiving drum of 100 r/min, an ambient temperature controlled at 25-35 C. and a humidity of 20-40%, the receiver wrapped in release paper is used.

(46) A preparation for the nano TiO.sub.2 aqueous dispersion is as follows: powder of the TiO.sub.2, deionized water, and sodium dodecylbenzene sulfonate are mixed in a weight ratio of 10:100:0.1 to obtain a mixed TiO.sub.2 solution, and followed by treating the mixed TiO.sub.2 solution with a low-power ultrasound for 2 h to prepare the nano TiO.sub.2 aqueous dispersion with a concentration of 10%.

Embodiment 5

(47) A preparation method for a nanocomposite fiber membrane material based on bio-based liquefied formaldehyde resin includes steps as follows.

(48) Step 1, a bio-based raw material, phenol, and polyethylene glycol are mixed in a mass ratio of 1:2:1 to obtain a first mixture, an acid as a catalyzer is added into the first mixture to react at 140 C. for 90 min to obtain a reacted mixture, then a sodium hydroxide is added into the reacted mixture to adjust a pH to be 7 thereby to obtain a second mixture, followed by cooling down the second mixture at 40 C. to obtain a bio-based liquefied product.

(49) Step 2, the bio-based liquefied product, the sodium hydroxide solution, a divalent alkali metal hydroxide, and a formaldehyde solution are mixed in a mass ratio of 1:0.4:0.1:1.3 to obtain a mixed solution, the mixed solution is heated up to 85 C. to react for 55 min to obtain a reacted solution, and followed by cooling down the reacted solution below 40 C. to obtain the BLF.

(50) Step 3, an aqueous solution of the BLF and an aqueous solution of PVA are stirred evenly to react at 50 C. for 40 min to obtain a reacted BLF-PVA solution, then the reacted BLF-PVA solution is cooled down to below 30 C. to obtain a BLF-PVA spinning solution as a precursor for coaxial electrospinning.

(51) Step 4, the BLF-PVA spinning solution is used as a core layer and a nano TiO.sub.2 aqueous dispersion is used as a shell layer, and a coaxial nozzle is used for the coaxial electrospinning to obtain an initial spun fiber film.

(52) Step 5, the initial spun fiber film is dried at 130 C. for 5 min to cure and shape, thereby obtaining the nanocomposite fiber membrane material of PVA-BLF/TiO.sub.2 with a special secondary structure. An SEM diagram of a nanocomposite fiber membrane is shown in FIG. 5.

(53) The bio-based raw material is bamboo powder, the acid is phosphoric acid, the divalent alkali metal hydroxide is magnesium hydroxide (Mg(OH).sub.2), a concentration of the sodium hydroxide solution is 40%, and a concentration of the formaldehyde solution is 37%.

(54) A dry matter content of the aqueous solution of the BLF is 10%, a concentration of the aqueous solution of the PVA is 10%, and the PVA is a medium degree of polymerization polymer. A preparation for the solution of the PVA is as follows. The PVA is added into water to swell at a normal temperature for 8 h, thereby obtaining a swelling solution, and followed by reacting the swelling solution at 90 C. for 2 h to obtain the solution of the PVA.

(55) Process parameters of the coaxial electrospinning includes a voltage of 12 kV, a shell thrust velocity of 1.6 mL/h, a core thrust velocity of 1 mL/h, a distance between a needle and a receiver of 30 cm, a speed of the receiving drum of 180 r/min, an ambient temperature controlled at 25-35 C. and a humidity of 20-40%, the receiver wrapped in release paper is used.

(56) A preparation for the nano TiO.sub.2 aqueous dispersion is as follows: powder of the TiO.sub.2, deionized water, and sodium dodecylbenzene sulfonate are mixed in a weight ratio of 10:100:0.1 to obtain a mixed TiO.sub.2 solution, and followed by treating the mixed TiO.sub.2 solution with a low-power ultrasound for 2 h to prepare the nano TiO.sub.2 aqueous dispersion with a concentration of 10%.

(57) The main performance test data of the steps and the prepared nanocomposite fiber membranes of embodiment 1 to embodiment 5 are shown in Table 1.

(58) TABLE-US-00001 TABLE 1 Steps and main performance test data of the prepared nanocomposite fiber membranes in the embodiment 1 to the embodiment 5 Embodiment 1 2 3 4 5 Step 1 bio-based raw shell shell poplar shell bamboo material powder of powder of powder powder of powder peanut peanut Juglans regia bio-based raw 1/1/0.5 1/2/1 1/2/1 1/2/0.5 1/2/1 material/phenol/ polyethylene glycol acid formic hydrochloric sulfuric oxalic phosphoric acid acid acid acid acid liquefaction 150 130 120 150 140 temperature ( C.) liquefaction time 45 90 60 80 120 (min) Step 2 bio-based liquefied 1/0.2/ 1/0.3/ 1/0.3/ 1/0.3/ 1/0.4/ product/sodium 0.2/1 0.2/1.2 0.3/1.2 0.4/1.3 0.1/1.3 hydroxide solution/divalent alkali metal hydroxide/ formaldehyde solution divalent alkali metal Ba(OH).sub.2 Zn(OH).sub.2 Ca(OH).sub.2 Zn(OH).sub.2 Mg(OH).sub.2 hydroxide resinization 80 85 75 90 85 temperature ( C.) resinization time 50 45 60 30 55 (min) Step 3 temperature of 50 55 60 60 50 reaction with PVA ( C.) time of reaction with 30 40 50 40 40 PVA (min) Step 4 voltage (kV) 15 18 20 12 12 shell thrust velocity 1.5 1.8 2.0 2.2 1.6 (mL/h) core thrust velocity 0.3 0.5 0.4 0.6 1 (mL/h) receiving distance 18 15 10 20 30 (cm) speed of the 200 150 300 100 180 receiving drum (r/min) Step 5 dry time (min) 10 15 10 15 5 main fiber diameter (nm) 400-450 150-200 300-350 200-250 350-400 properties elongation at break 5.79 6.15 6.32 6.06 5.83 of fiber (%) membranes formaldehyde 86.8 92.3 88.1 90.3 87.9 removal rate (%) methylene blue 88.6 93.5 89.7 92.8 86.4 removal rate (%) renewability 71.8 75.1 71.2 72.4 70.3 (Removal rate after 10 cycles) % SEM FIG.1 FIG. 2 FIG. 3 FIG. 4 FIG. 5

(59) The method for testing the tensile elongation at break of the nanocomposite fiber membrane is as follows: a Model 3365 Universal Testing Machine (Instron Co., USA) is used to test the tensile properties of the sample. According to the national standard ASTM D882-09, the fiber film is cut into test pieces with a length of 15 mm and a width of 5 mm. The tensile rate is set to 10 millimeters per minute (mm/mmn), and the temperature and the humidity are maintained at room temperature and 30%, respectively. Three samples of the nanocomposite fiber membrane material under the same condition are taken to measure separately.

(60) The formaldehyde adsorption testing method includes: a sealed space is constructed, and a formaldehyde solution is diluted with deionized water in a 1:50 ratio to obtain a diluted formaldehyde solution and then the diluted formaldehyde solution is sprayed. A formaldehyde detector (MVEF500) is used to observe real-time changes in formaldehyde levels within the space. Once readings of the formaldehyde detector are stabilized, the nanocomposite fiber membranes prepared in the embodiments 1 to 5 are placed into the space to test formaldehyde adsorption performances of the nanocomposite fiber membrane materials. A formula for calculating a removal rate of the formaldehyde is as follows:

(61) $M=\frac{C0-C1}{C0}100\%,$ where M represents the removal rate of the formaldehyde (%); C0 represents an initial concentration of the formaldehyde (mg/m.sup.3); C1 represents a final concentration of the formaldehyde (mg/m.sup.3).

(62) A testing method for the adsorption performance of methylene blue includes: 100 mL of methylene blue solutions with a certain mass concentration is prepared, 0.1 gram (g) of the nanocomposite fiber membranes prepared in the embodiments 1 to 5 are added into the methylene blue solutions, respectively. The methylene blue solutions added with the nanocomposite fiber membranes are oscillated at a constant temperature water bath to adsorb (at a speed of 110 r/min).

(63) The characteristic wavelength A of the methylene blue is 664 nanometers (nm). The UV-visible spectrophotometer is adjusted to the corresponding parameters. After the oscillation and the adsorption is finished, the absorbances of the obtained solutions (i.e., the methylene blue solutions added with the nanocomposite fiber membranes) are measured, and then the absorbances are substituted into the standard curve formula to calculate the mass concentration of the methylene blue. An adsorption amount of the methylene blue Q and a removal rate of the methylene blue P are calculated using the following formulas:

(64) $Q=\left(C_0-C_e\right)V/m,p=\frac{c_0-c_e}{c_0}100\%;$ where Q represents the adsorption amount of the methylene blue, milligram per gram (mg/g); C.sub.0 represents an initial concentration of the methylene blue before adsorption, milligram per liter (mg/L); C.sub.e represents an equilibrium concentration of the methylene blue after adsorption, mg/L; V represents a volume of the methylene blue solution, liter (L); m represents a mass of the nanocomposite fiber membrane, gram (g).

(65) In the disclosure, the bio-based raw material used in the preparation method of bio based liquefied resin nanocomposite fiber membrane material is changed, including wood powder, shell powder of peanut, shell powder of Juglans regia, bamboo powder, and other different bio based raw materials, different acids such as formic acid, sulfuric acid, hydrochloric acid, oxalic acid, and phosphoric acid are used as catalysts, and parameters of device are adjusted according to the raw materials during the preparation process, so that five embodiments are completed. Through specific performance testing of these embodiments, it can be seen that the nanocomposite fiber membrane material prepared by the disclosure has excellent performance, high utilization rate, and is also environmentally friendly. The average fiber diameter of the nanocomposite fiber membrane prepared in the embodiments 1 to 5 is 150-450 nm, and the specific surface area is 500-700 m.sup.2/g. The porosity exceeds 60%, and the tensile elongation at break ranges from 5.5% to 6.5%, demonstrating excellent filtration performance.

(66) Taking the methylene blue as an example, the removal rate exceeds 85% after 8 hours while having a strong adsorption rate of volatile organic compounds (VOCs), taking formaldehyde as an example, with a removal rate of up to 85-95%. In addition, it also demonstrates excellent regeneration performance. After 10 cycles of degradation and adsorption, the methylene blue removal rate of the final sample still exceeds 70% after irradiating the membrane surface with a halogen lamp, which can be developed as adsorption materials for water and air purification.

(67) As shown in FIGS. 1-5, it can be seen that the bio-based raw materials can form a fibrous network structure with a diameter of about 150-450 nm after the process of liquefied resin electrospinning. The coaxial co-spinning has successfully loaded the nano TiO.sub.2 onto the bio-based fibers. The degree of liquefaction and degradation varies with different bio-based materials, leading to different degrees of branching and hence different surface tensions. Moreover, the ortho-positioning effect of different divalent metal ions differs, which results in different viscoelastic properties of the molecules formed, causing variations in viscosity. Additionally, the conductivities of the liquefied resin formed by different acid catalysis also vary, which will affect the morphological structure of the electrospun fibers. The liquefied resin catalyzed by the hydrochloric acid and the sulfuric acid has a higher conductivity, resulting in denser fibers (FIGS. 2 and 3). The liquefied resin catalyzed by the acetic acid, the oxalic acid, and the phosphoric acid has a lower conductivity, resulting in relatively looser fibers (FIGS. 1, 4, and 5). The zinc hydroxide has the best ortho and para-positioning effect, presenting more linear structures with better toughness, and the fibers formed are finer in diameter (FIGS. 2 and 5).

(68) It should be noted that the described embodiments are only some of the embodiments of the disclosure, not all of them. Based on the embodiments in the disclosure, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the disclosure.