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CN-121972099-A - TiO-loaded2Composite phase-change chitosan aerogel with bionic sea urchin-like asymmetric structure of rGO heterojunction and preparation method and application thereof

CN121972099ACN 121972099 ACN121972099 ACN 121972099ACN-121972099-A

Abstract

The invention discloses a TiO 2 /rGO heterojunction-loaded bionic sea urchin-shaped asymmetric structure composite phase-change chitosan aerogel, a preparation method and application thereof, wherein argon plasma is adopted to etch GO, tetrabutyl titanate is dropwise added step by step to prepare a TiO 2 /rGO heterojunction, an interfacial polymerization method is adopted to prepare a multilevel structure phase-change microcapsule, the heterojunction is mixed with a chitosan solution, a customized asymmetric mold and a unidirectional freezing process are adopted to prepare a bionic sea urchin-shaped asymmetric chitosan aerogel skeleton, a vacuum auxiliary impregnation method is adopted to fix the phase-change microcapsule, and then polydopamine in-situ cladding is adopted to obtain the TiO 2 /rGO heterojunction-loaded bionic sea urchin-shaped asymmetric structure composite phase-change chitosan aerogel, the removal rate of the VOCs is more than or equal to 80% at low temperature, the phase-change microcapsule after 100 times of circulation is less than or equal to 3%, and the structural stability and the circulation durability are excellent, and the method is suitable for efficient purification of the VOCs in low-temperature closed scenes such as cold chain workshops and winter.

Inventors

  • LIU YUQING
  • BAI TIANYU
  • YANG XUEQIN

Assignees

  • 苏州大学

Dates

Publication Date
20260505
Application Date
20260408

Claims (10)

  1. 1. The preparation method of the composite phase-change chitosan aerogel with the bionic sea urchin-shaped asymmetric structure and loaded with the titanium dioxide/reduced graphene oxide heterojunction is characterized by comprising the following steps of: (1) Performing argon plasma etching on the graphene oxide dispersion liquid to form a double-scale defect of the graphene oxide, dripping tetrabutyl titanate into the etched graphene oxide dispersion liquid at different speeds in two steps to respectively form a titanium dioxide nanobelt and a titanium dioxide microcrystal; (2) Mixing the core layer material and the shell layer material according to the mass ratio of (6-8) (2-4), adding an emulsifying agent and toluene, uniformly stirring to obtain an oil phase, dissolving melamine in water, adding a formaldehyde solution to obtain a melamine-formaldehyde prepolymer aqueous solution, dripping the oil phase into the aqueous phase, stirring and dispersing, adding the mortise and tenon tooth material and the anchor point material, shearing and emulsifying, polymerizing at 70-80 ℃, solidifying at 80-100 ℃, separating, washing and drying to obtain a phase change microcapsule consisting of a core layer, a shell layer coated on the outer side of the core layer, mortise teeth protruding on the surface of the shell layer and anchor points loaded on the surface of the mortise and tenon teeth; (3) Dispersing the titanium dioxide/reduced graphene oxide heterojunction obtained in the step (1) in water to obtain titanium dioxide/reduced graphene oxide heterojunction dispersion liquid with the concentration of 0.5-1 g/L, dissolving chitosan powder in dilute acetic acid solution to obtain chitosan solution with the concentration of 1-3% w/v, mixing the titanium dioxide/reduced graphene oxide heterojunction dispersion liquid and the chitosan solution according to the volume ratio of 1 (3-5) to obtain composite sol, pouring the composite sol into a custom mold containing a plane side and a convex array side, performing unidirectional freezing treatment from top to bottom to enable the chitosan and the titanium dioxide/reduced graphene oxide heterojunction to self-assemble to form a bionic sea urchin-shaped nanofiber bundle, and performing freeze drying to obtain a bionic sea urchin-shaped asymmetric structured chitosan aerogel skeleton carrying the titanium dioxide/reduced graphene oxide heterojunction by adopting thermal crosslinking or glutaraldehyde steam chemical crosslinking treatment; (4) Dispersing the phase-change microcapsule obtained in the step (2) in ethanol according to a solid-to-liquid ratio of 1 (9-11) to obtain a phase-change microcapsule suspension, immersing the bionic sea urchin-shaped asymmetric chitosan aerogel skeleton loaded with the titanium dioxide/reduced graphene oxide heterojunction obtained in the step (3) in the phase-change microcapsule suspension under a vacuum condition of-0.05 MPa to-0.15 MPa for 30-60 min, immersing 3-5h after releasing vacuum, and drying in vacuum to obtain the bionic sea urchin-shaped asymmetric composite phase-change chitosan aerogel skeleton loaded with the titanium dioxide/reduced graphene oxide heterojunction, wherein the loading capacity of the phase-change microcapsule is 30-40 wt%; (5) Dissolving dopamine hydrochloride in a tris hydrochloride buffer solution with the pH value of 8.0-8.8 to obtain a dopamine solution with the concentration of 0.5-4 mg/mL, immersing the bionic sea urchin-shaped asymmetric structure composite phase-change chitosan aerogel skeleton of the loaded titanium dioxide/reduced graphene oxide heterojunction obtained in the step (4) in the dopamine solution, so that dopamine is polymerized on the surface of the bionic sea urchin-shaped asymmetric structure composite phase-change chitosan skeleton of the loaded titanium dioxide/reduced graphene oxide heterojunction in situ to form a polydopamine coating layer with the thickness of 50-100 nm, and drying to obtain the bionic sea urchin-shaped asymmetric structure composite phase-change chitosan aerogel of the loaded titanium dioxide/reduced graphene oxide heterojunction.
  2. 2. The method according to claim 1, wherein in the step (1), the concentration of the graphene oxide dispersion liquid is 1-3 g/L, the parameters of the argon plasma etching are that the power is 45-55W, the time is 8-12 min, the vacuum degree is 0.05-0.2 Pa, and the argon flow rate is 5-15 sccm.
  3. 3. The method according to claim 1, wherein in the step (1), tetrabutyl titanate is firstly dripped at a rate of 0.5-1 mL/min to form a titanium dioxide nanobelt, tetrabutyl titanate is dripped at a rate of 2-3 mL/min to form titanium dioxide microcrystals, the volume ratio of tetrabutyl titanate dripped at a rate of 0.5-1 mL/min to the etched graphene oxide dispersion is (2-4): 100, the volume ratio of tetrabutyl titanate dripped at a rate of 2-3 mL/min to the etched graphene oxide dispersion is (1-3): 100, the mass ratio of catechol to graphene oxide is (0.2-0.4): 100, the temperature of the hydrothermal reaction is 170-190 ℃ and the time is 10-14 h.
  4. 4. The preparation method according to claim 1, wherein in the step (1), the mass ratio of titanium dioxide to reduced graphene oxide in the titanium dioxide/reduced graphene oxide heterojunction is (3-4) 1, and the particle size of the titanium dioxide/reduced graphene oxide heterojunction is 80-150 nm.
  5. 5. The preparation method of the chitosan-polyurea-nano titanium dioxide compound is characterized in that in the step (2), chitosan is dissolved in dilute acetic acid solution, nano titanium dioxide is added to be uniformly dispersed, isophorone diisocyanate is added to be subjected to heating and stirring reaction, separation washing and drying treatment, and the chitosan-polyurea-nano titanium dioxide compound is obtained, wherein the preparation method of the chitosan-dopamine copolymer is characterized in that chitosan is dissolved in dilute acetic acid solution, dopamine compound is added to be regulated to be acidic, a cross-linking agent is added to be subjected to stirring reaction, and the chitosan-dopamine copolymer is obtained through dialysis purification and freeze drying treatment, wherein the mass ratio of the total mass of core layer material to shell layer material to that of tenon-mortise tooth material is 100 (4-6), and the mass ratio of the total mass of core layer material to shell material to anchor point material is 100 (2-4).
  6. 6. The preparation method of the phase-change microcapsule according to claim 1, wherein in the step (2), the diameter of a core layer of the phase-change microcapsule is 8-11 μm, the thickness of a shell layer of the phase-change microcapsule is 150-250 nm μm, the particle size of the phase-change microcapsule is 8-12 μm, 4-6 mortise teeth are arranged on the surface of the phase-change microcapsule, the length of the mortise teeth is 3-5 μm, the width of the mortise teeth is 80-100 nm, the height of the mortise teeth is 50-80 nm, 6-8 anchor points are loaded on the surface of each mortise tooth, and the distance is 10-15 nm.
  7. 7. The method according to claim 1, wherein in the step (3), the custom mold comprises a closing baffle plate, a detachable upper cover plate and a detachable lower cover plate, wherein the plane side and the protrusion array side are oppositely arranged, the closing baffle plate is vertically connected, the protrusion array side is provided with cylindrical protrusions, the diameter of each cylindrical protrusion is 0.2-0.3 mm, the height of each cylindrical protrusion is 0.3-0.5 mm, the protrusion interval is 0.5-0.8 mm, the arrangement mode is regular triangle arrangement, the temperature of the unidirectional freezing treatment is-80 ℃ to-100 ℃, the time is 4-6 h, the temperature of the thermal cross-linking is 120-150 ℃, and the time is 1-3 h.
  8. 8. The method according to claim 1, wherein in the step (3), the chitosan aerogel skeleton with bionic asymmetric structure has primary main pores with a pore diameter of 80-100 μm and secondary branch pores with a pore diameter of 12-15 μm.
  9. 9. A biomimetic echinoid-shaped asymmetric-structure composite phase-change chitosan aerogel loaded with titanium dioxide/reduced graphene oxide heterojunction prepared by the preparation method of any one of claims 1-8.
  10. 10. An application of the composite phase-change chitosan aerogel with the bionic sea urchin-like asymmetric structure loaded with the titanium dioxide/reduced graphene oxide heterojunction in purifying volatile organic pollutants.

Description

TiO 2/rGO heterojunction-loaded bionic sea urchin-shaped asymmetric structure composite phase-change chitosan aerogel and preparation method and application thereof Technical Field The invention relates to the technical field of functional aerogel materials, in particular to a TiO 2/rGO heterojunction-loaded bionic sea urchin-shaped asymmetric structure composite phase-change chitosan aerogel, and a preparation method and application thereof. Background Volatile organic pollutants (VOCs) are one of the main sources of atmospheric pollution, and emission control in low-temperature closed environments (such as cold chain workshops, winter rooms, low-temperature storage spaces, etc.) has become a key problem in the field of environmental management. The environmental temperature is usually maintained at-10 ℃ to 15 ℃, the thermal activity of VOCs molecules is obviously reduced, the VOCs molecules are easily adsorbed on aerosol particles or equipment condensation surfaces, the traditional purification technology faces multiple bottlenecks, the traditional adsorption technology (such as activated carbon adsorption) has certain initial adsorption capacity at low temperature, but is extremely easy to lose effectiveness due to adsorption saturation, a large amount of heat energy is consumed for adsorbent regeneration, secondary pollution risks exist, the pure thermal catalysis technology needs to maintain a high-temperature reaction environment (usually more than or equal to 50 ℃), the heat is rapidly dissipated in a low-temperature scene, the energy efficiency ratio is rapidly reduced, the actual purification requirements cannot be met, the photocatalytic technology relies on photo-generated carriers on the catalyst surfaces to oxidize and degrade the VOCs, but the molecular activity is insufficient at low temperature, and the traditional photocatalyst (such as pure TiO 2) has high photo-generated electron-hole recombination rate and low photo-thermal conversion efficiency, so that the catalytic performance is further limited. In order to solve the problems, chinese patent CN113416345A discloses a chitosan-diatomite composite phase-change aerogel, although low-temperature thermal energy storage and release are realized, a photocatalysis and energy storage function component is not compounded, the catalysis and energy storage function is split, the synergism of VOCs degradation and heat regulation cannot be realized, chinese patent CN113398904A discloses a catalyst for medium-low temperature photocatalysis and thermocatalysis of VOCs, but the catalyst lacks a phase-change energy storage synergistic mechanism, the heat is easy to rapidly dissipate at low temperature, a substrate is a titanium dioxide nanotube, the biocompatibility is poor and the degradation is difficult, the PtCu/TiO 2 photo-thermal catalyst disclosed in Chinese patent CN113070073A has the toluene degradation rate reaching 80 percent and needs to depend on a 77 ℃ high-temperature environment, the adaptation temperature range is 25-200 ℃, the catalysis efficiency is almost zero at the low temperature of minus 10 ℃ to 15 ℃, and the VOCs treatment requirements of low-temperature scenes such as a cold chain workshop cannot be met completely. In addition, the prior art has the following common problems that firstly, the function coordination is insufficient, an effective coordination system is not formed by photo-thermal catalysis and phase-change energy storage, the core contradiction that the molecular activity is low and the heat is easy to dissipate at low temperature cannot be solved, secondly, the structural design is unreasonable, most materials adopt symmetrical porous structures, so that the mass transfer paths of VOCs are disordered, the contact rate of active sites of the catalyst is low, the purification efficiency is limited, thirdly, the stability and the environmental protection are poor, the phase-change microcapsule adopts a physical filling mode, the phase-change microcapsule is easy to dissipate in the recycling process, and most materials depend on noble metal components (such as Pt and Cu) or non-biomass base materials, so the defects of high cost, high energy consumption, poor biocompatibility, easiness in causing secondary pollution and the like are overcome. Therefore, developing a composite aerogel material with low-temperature efficient catalysis, photo-thermal-energy storage function coordination, mass transfer path optimization and green environmental protection characteristics, and realizing efficient and stable purification of VOCs in a-10 ℃ to 15 ℃ low-temperature closed environment becomes a technical problem to be solved in the field. Disclosure of Invention The invention aims to solve the technical problems that the existing VOCs purifying material has suddenly reduced catalytic efficiency in a low-temperature closed environment of-10-15 ℃, the photocatalysis and phase change energy storage functions are not coordinated