A foamed carbon material, its preparation method and use

Abstract

The present application belongs to the technical field of catalyst carrier preparation, and provides a kind of foam carbon material and its preparation method and application.The present application mixes seaweed residue, phenol and formaldehyde aqueous solution to carry out polycondensation reaction, and obtains phenolic resin;phenolic resin, surfactant, foaming agent and curing agent are mixed to foam, and obtain solidified foam;solidified foam and activator are mixed, and carbonization treatment is carried out, and foam carbon material is obtained.The foam carbon material obtained by the present application has low density, three-dimensional macrostructure, high light transmittance and high adsorption;at the same time, the foam carbon material is a monolithic material, and is convenient to recycle.In addition, the foam carbon material of the present application can uniformly adhere and disperse catalytically active ingredients;especially, the high light transmittance characteristic of the foam carbon material enables titanium dioxide loaded on the foam carbon material to fully utilize visible light and fully exert its photocatalytic degradation capacity.In addition, the catalytically active ingredients have strong bonding force with the foam carbon material, and are not easy to fall off, with long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst carrier preparation, in particular to a kind of foam carbon material and its preparation method and application. BACKGROUND

[0002] Catalyst can accelerate reaction rate, improve reaction efficiency, and is widely used. Most catalysts are solid particles, but solid particles are difficult to recover when applied. Therefore, in order to simplify the recovery of catalyst, the catalyst is generally loaded on the carrier at present. The substances commonly used as catalyst carriers include silicon dioxide, clay materials and foam materials. Foam materials are most commonly used in catalyst loading due to their light weight. When foam materials are used to load photocatalytic degradation catalysts, new requirements for the light transmittance of foam materials are proposed. However, the existing foam materials pay little attention to light transmittance. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a kind of foam carbon material and its preparation method and application. The foam carbon material prepared by the preparation method provided by the present application has high light transmittance.

[0004] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0005] The present application provides a preparation method of a foam carbon material, comprising the following steps:

[0006] Mixing seaweed residue, phenol and formaldehyde aqueous solution to carry out polycondensation reaction to obtain phenolic resin;

[0007] Mixing the phenolic resin, surfactant, foaming agent and curing agent to carry out foaming to obtain cured foam;

[0008] Mixing the cured foam and activating agent to carry out carbonization treatment to obtain the foam carbon material.

[0009] Preferably, the concentration of the formaldehyde aqueous solution is 20-40wt%, and the mass ratio of the seaweed residue, phenol and formaldehyde aqueous solution is 40-70:220-260:80-120.

[0010] Preferably, the temperature of the polycondensation reaction is 60-80℃, and the time is 2-3h.

[0011] Preferably, the surfactant includes one or more of non-ionic surfactant, anionic surfactant, fatty acid, copolyether and polyether-siloxane polymer;

[0012] The curing agent includes hydrochloric acid, and the mass fraction of the hydrochloric acid is 20-40%;

[0013] The foaming agent is n-hexane;

[0014] The mass of the surfactant is 5-15% of the mass of the phenol novolac resin;

[0015] The mass of the foaming agent is 2-5% of the mass of the phenol novolac resin;

[0016] The mass of the curing agent is 1-10% of the mass of the phenol novolac resin;

[0017] The foaming temperature is 120-180℃, and the time is 1-4h.

[0018] Preferably, the activator includes one or more of zinc chloride, potassium hydroxide and iron phthalocyanine;

[0019] The mass ratio of the cured foam and the activator is 1-5:1-5.

[0020] Preferably, the carbonization treatment temperature is 500-1000℃, and the holding time is 1-5h; the carbonization treatment atmosphere includes nitrogen, and the temperature rising rate to the carbonization treatment temperature is 1-20℃ / min.

[0021] The present application also provides a foam carbon material prepared by the preparation method, and the light transmittance of the foam carbon material is 2.5-18%, and the bulk density is 0.05-1.5g / cm 3 .

[0022] The present application also provides a composite catalyst material, which includes a carrier and a catalytically active component attached to the carrier, and the carrier is the foam carbon material.

[0023] Preferably, the catalytically active component includes titanium dioxide, bismuth molybdate, bismuthyl bromide, tricobalt tetroxide or zinc oxide.

[0024] Preferably, when the catalytically active component is titanium dioxide, the composite catalyst material can photocatalytically degrade antibiotics, and the antibiotics include one or more of tetracycline antibiotics, sulfonamide antibiotics and quinolone antibiotics.

[0025] The present application provides a preparation method of a foam carbon material.

[0026] The present application takes seaweed residue as a biomass raw material, phenol liquefies the seaweed residue into small molecular substances, the small molecular substances and formaldehyde occur polycondensation reaction to form a phenolic resin; the phenolic resin, a surfactant, a foaming agent and a curing agent are mixed to form a cured foam, the surfactant can improve the foaming stability and uniformity, and finally the uniformity of the pores of the foam carbon material is embodied; then an activating agent and the cured foam are mixed to perform carbonization treatment, the activating agent further optimizes the pores in the cured foam, and finally the foam carbon material with low density and three-dimensional macrostructure is formed. The macroscopic performance of the foam carbon material obtained by the present application is high light transmittance, low bulk density and high adsorption; meanwhile, the foam carbon material is a monolithic material, and is convenient to recycle. The data of the examples show that the light transmittance of the obtained foam carbon material is 2.5-18%, and the bulk density is 0.05-1.5 g / cm 3 .

[0027] The present application also provides a composite catalyst material, comprising a carrier and a catalytically active component attached to the carrier, and the carrier is the foam carbon material described in the above technical solution. The foam carbon material of the present application can uniformly attach and disperse the catalytically active component; especially, for the photocatalytic degradation catalyst titanium dioxide, the high light transmittance characteristic of the foam carbon material makes the titanium dioxide fully utilize solar energy and fully exert its photocatalytic degradation capacity. In addition, the catalytically active component has strong bonding force with the foam carbon material and is not easy to fall off, and has long service life. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a physical picture of seaweed;

[0029] Figure 2 It is a physical picture of seaweed residue;

[0030] Figure 3 It is a physical picture of the composite titanium dioxide material obtained in Example 1;

[0031] Figure 4 It is an SEM picture of the composite titanium dioxide material A1 obtained in Example 1 at different magnifications;

[0032] Figure 5 It is a degradation effect picture of the composite titanium dioxide material A1 obtained in Example 1 on ofloxacin at different pH values and a degradation effect picture of the catalyst D5 obtained in Comparative Example 5 on ofloxacin at pH 9;

[0033] Figure 6 It is a degradation effect picture of the composite titanium dioxide material A1 obtained in Example 1 on sulfamethoxazole at different pH values and a degradation effect picture of the catalyst D5 obtained in Comparative Example 5 on ofloxacin at pH 9;

[0034] Figure 7The degradation of antibiotics by the composite titanium dioxide material A1 obtained in Example 1 is shown in the following figure;

[0035] Figure 8 The XRD spectrum of the composite titanium dioxide material A1 obtained in Example 1 after 4 cycles is shown in the following figure. DETAILED DESCRIPTION

[0036] The application provides a preparation method of a foamed carbon material, comprising the following steps:

[0037] The seaweed residue, phenol and formaldehyde aqueous solution are mixed to perform a polycondensation reaction to obtain a phenolic resin;

[0038] The phenolic resin, a surfactant, a foaming agent and a curing agent are mixed to perform foaming to obtain a cured foam;

[0039] The cured foam and an activating agent are mixed to perform carbonization treatment to obtain the foamed carbon material.

[0040] Unless otherwise specified, the raw materials used in the application are preferably commercially available products.

[0041] The seaweed residue, phenol and formaldehyde aqueous solution are mixed to perform a polycondensation reaction to obtain a phenolic resin.

[0042] In the application, the seaweed residue refers to the residue remaining after iodine, mannitol and sodium alginate are extracted from seaweed in industry; and the seaweed preferably comprises one or more of kelp, laminaria, enteromorpha, undaria pinnatifida, sargassum fusiforme, sargassum vachellianum and gelidium amansii. Figure 1 A physical picture of seaweed is shown in the following figure; Figure 2 A physical picture of seaweed residue is shown in the following figure. In the application, in recent years, the seaweed processing industry is developing rapidly, and with the increasing maturity of the technology for extracting seaweed glue from seaweed in seaweed processing enterprises, the output of seaweed residue is increasing. At present, most factories sell seaweed residue as a feed additive or directly discard it, and the seaweed residue cannot be effectively utilized. In the application, the seaweed residue is used to prepare a foamed carbon material, and the economic benefit of the seaweed residue is improved.

[0043] In the application, the concentration of the formaldehyde aqueous solution is preferably 20-40wt%, and specifically can be 20wt%, 25wt%, 30wt%, 35wt%, 37wt% or 40wt%.

[0044] In the application, the mass ratio of the seaweed residue, phenol and formaldehyde aqueous solution is preferably 40-70:220-260:80-120, and further preferably 60:240:100.

[0045] In the present application, the temperature of the condensation reaction is preferably 60-80℃, and can be specifically 60℃, 65℃, 70℃, 75℃ or 80℃; the time is preferably 2-3h, and is further preferably 2.5h.

[0046] After the condensation reaction, the present application preferably directly proceeds to the subsequent operation without any treatment.

[0047] In the present application, the phenol can liquefy the seaweed residue into small molecular substances, and the small molecular substances and formaldehyde can undergo condensation reaction to form a phenolic resin.

[0048] After obtaining the phenolic resin, the present application mixes the phenolic resin, a surfactant, a foaming agent and a curing agent to perform foaming, and obtains a cured foam.

[0049] In the present application, the surfactant preferably includes one or more of non-ionic surfactants, anionic surfactants, fatty acids, copolyether and polyether-siloxane polymers, and is further preferably a non-ionic surfactant. In the present application, the non-ionic surfactant preferably includes Tween-80 and / or nonylphenol, and is further preferably Tween-80. In the present application, the anionic surfactant preferably includes one or more of sodium dodecyl sulfate (SDS), cetyl sulfate and sodium dodecyl benzene sulfonate. In the present application, the fatty acid preferably includes one or more of arachidonic acid, linoleic acid and linolenic acid. In the present application, the copolyether preferably includes dihydroxy propylene oxide-ethylene oxide copolyether and / or tetrahydrofuran copolyether. In the present application, the polyether-siloxane polymer is preferably a polysiloxane-polyalkoxy ether copolymer. In the present application, the mass of the surfactant is preferably 5-15% of the mass of the phenolic resin, and is specifically preferably 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%. In the present application, the surfactant makes the foaming stable and uniform, and ultimately reflects in the uniform pores of the foam carbon material.

[0050] In the present application, the foaming agent preferably includes n-hexane. In the present application, the mass of the foaming agent is preferably 2-5% of the mass of the phenolic resin, and is specifically preferably 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%.

[0051] In the present application, the curing agent preferably includes hydrochloric acid, and the mass fraction of the hydrochloric acid is preferably 20-40%, and is specifically preferably 37%. In the present application, the mass of the curing agent is preferably 1-10% of the mass of the phenolic resin, and is specifically preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0052] In the present application, the foaming temperature is preferably 120-180℃, further preferably 130-160℃, and particularly preferably 120℃, 130℃, 140℃, 150℃, 160℃, 170℃ or 180℃; and the foaming time is preferably 1-4h, further preferably 2-3h, and particularly preferably 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h. In the present application, the foaming is preferably carried out in a high-pressure autoclave.

[0053] After the foaming, the present application preferably directly proceeds to the subsequent operation without any post-treatment.

[0054] After obtaining the cured foam, the present application mixes the cured foam and an activator to perform carbonization treatment, thereby obtaining a foam carbon material.

[0055] In the present application, the activator preferably comprises one or more of zinc chloride, potassium hydroxide and iron phthalocyanine, and is further preferably zinc chloride. In the present application, the activator can activate the pore structure.

[0056] In the present application, the mass ratio of the cured foam to the activator is preferably 1-5:1-5, further preferably 1:1-5, and particularly preferably 1:1, 1:2, 1:3, 1:4 or 1:5.

[0057] In the present application, the carbonization treatment is preferably performed at a temperature of 500-1000℃, further preferably 600-900℃, and particularly preferably 500℃, 600℃, 700℃, 800℃, 900℃ or 1000℃; and the holding time is preferably 1-5h, further preferably 2-4h, and particularly preferably 1h, 2h, 3h, 4h or 5h. In the present application, the atmosphere of the carbonization treatment preferably comprises nitrogen (N2). In the present application, the heating rate for heating to the temperature of the carbonization treatment is preferably 1-20℃ / min, and particularly preferably 1℃ / min, 5℃ / min, 10℃ / min, 15℃ / min or 20℃ / min.

[0058] After the carbonization treatment, the present application preferably further comprises sequentially performing acid washing, water washing and drying on the obtained solid product. In the present application, the acid washing agent is preferably hydrochloric acid, and the concentration of the hydrochloric acid is preferably 1mol / L. In the present application, the water washing agent is preferably deionized water. In the present application, the drying time is preferably 24h, and the drying is preferably performed in an oven.

[0059] The present application also provides a foam carbon material prepared by the preparation method described in the above technical solution, wherein the light transmittance of the foam carbon material is 2.5-18%, and the bulk density is 0.15-1.5g / cm 3 .

[0060] The application further provides a composite catalyst material, comprising a carrier and a catalytically active component attached to the carrier, wherein the carrier is the foamed carbon material as described in the above technical solution.

[0061] The composite catalyst material provided by the application comprises a carrier, wherein the carrier is the foamed carbon material as described in the above technical solution.

[0062] The composite catalyst material provided by the application comprises a catalytically active component attached to the carrier, wherein the catalytically active component comprises titanium dioxide, bismuth molybdate, bismuthyl bromide, tricobalt tetroxide or zinc oxide.

[0063] In the application, when the catalytically active component is titanium dioxide, the composite catalyst material (referred to as a composite titanium dioxide material) can photocatalytically degrade antibiotics, wherein the antibiotics comprise one or more of tetracycline antibiotics, sulfonamide antibiotics and quinolone antibiotics.

[0064] In the application, the photocatalytic degradation of antibiotics by the composite titanium dioxide material preferably comprises the following steps:

[0065] The composite titanium dioxide material is placed in a water body containing antibiotics, and adsorption and photocatalytic degradation are sequentially performed. In the application, the pH value of the water body containing antibiotics is preferably 7-9. In the application, the adsorption time is preferably 12 h. In the application, the adsorption is preferably performed in the dark. In the application, the light source for photocatalytic degradation is preferably a xenon lamp, and the power of the xenon lamp is preferably 300 W. In the application, the temperature for photocatalytic degradation is preferably 20-40℃.

[0066] In the application, when the catalytically active component is titanium dioxide, the preparation method of the composite catalyst material preferably comprises the following steps:

[0067] The foamed carbon material is immersed in a titanium dioxide sol, and the immersed seaweed foamed carbon is sequentially dried and carbonized to obtain the composite catalyst material.

[0068] In the application, the titanium dioxide sol is preferably prepared by a sol-gel method, and the sol-gel method preferably comprises the following steps:

[0069] Tetrabutyl titanate is added dropwise into anhydrous ethanol to obtain solution A;

[0070] After water and anhydrous ethanol are mixed, a mixed solvent is obtained, and concentrated nitric acid is added dropwise into the mixed solvent to obtain solution B;

[0071] The solution B is added dropwise into the solution A, and stirring is performed to obtain the titanium dioxide sol.

[0072] In the present application, the volume ratio of tetrabutyl titanate and anhydrous ethanol in the solution A is preferably 1-5:5-10, further preferably 3:5.

[0073] In the present application, the volume ratio of water and anhydrous ethanol in the solution B is preferably 4-8:25-40, further preferably 6:32; the volume ratio of concentrated nitric acid and anhydrous ethanol is preferably 0.5-1:10-20. In the present application, the mass fraction of the concentrated nitric acid is preferably 68%.

[0074] In the present application, the volume ratio of the solution A and the solution B is preferably 30-50:40-60.

[0075] In the present application, the rotation speed of the stirring is preferably 1000-3000 rpm, further preferably 2000 rpm, and specifically preferably 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm or 3000 rpm; the time is preferably 30-120 min, and specifically preferably 30 min, 60 min, 90 min or 120 min.

[0076] In the present application, the titanium dioxide sol is preferably a clear yellow solution.

[0077] In the present application, the time of the impregnation is preferably 30-120 min, and the impregnation is preferably carried out under stirring.

[0078] In the present application, the drying preferably comprises natural air drying and oven drying in sequence. In the present application, the temperature of the oven drying is preferably 100℃-150℃, further preferably 110℃-140℃, and specifically preferably 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃; the time is preferably 1-5 h, and specifically preferably 1 h, 2 h, 3 h, 4 h or 5 h. In the present application, after the natural air drying, a layer of titanium dioxide sol coating is coated on the seaweed foam carbon.

[0079] In the present application, the carbonization temperature is preferably 300℃-600℃, and specifically preferably 300℃, 400℃, 500℃ or 600℃; the time is preferably 1-5 h, and specifically preferably 1 h, 2 h, 3 h, 4 h or 5 h. In the present application, the carbonization is preferably carried out in a muffle furnace.

[0080] After the carbonization, the present application preferably further comprises: after the obtained product is cooled to room temperature, compressed air is introduced into the product to obtain the foam carbon material. In the present application, the introduction of the compressed air can remove the pore clogging material.

[0081] In the present application, the carbonization can increase the binding force of TiO2 and the foam carbon material.

[0082] The foam carbon material, the preparation method and the application thereof provided by the present application are described in detail below in combination with examples, but they cannot be understood as limitations to the protection scope of the present application.

[0083] Example 1

[0084] (1) Preparation of the foam carbon material: kelp residue, phenol and 37wt% formaldehyde aqueous solution (the mass ratio of kelp residue, phenol and 37wt% formaldehyde aqueous solution is 60:240:100) were subjected to polycondensation reaction at 70°C for 2.5h to obtain a phenol-formaldehyde resin. The obtained phenol-formaldehyde resin was mixed with surfactant Tween-80, foaming agent n-hexane and curing agent 37wt% hydrochloric acid (wherein the mass of Tween-80 is 10% of the mass of the phenol-formaldehyde resin, the mass of n-hexane is 3% of the mass of the phenol-formaldehyde resin, and the mass of hydrochloric acid is 6% of the mass of the phenol-formaldehyde resin), and then put into an autoclave to be foamed at 150°C for 2h to obtain a cured foam. The cured foam was mixed with ZnCl2 (the mass ratio of the cured foam and ZnCl2 is 1:3), and then subjected to carbonization treatment under N2 protection at a temperature rising rate of 5°C / min to 800°C for 2h. After the carbonization treatment, the carbonization product was washed with 1mol / L hydrochloric acid solution and deionized water in sequence, and then placed in an oven to be dried for 24h to obtain the foam carbon material.

[0085] (2) Preparation of the titanium dioxide sol by sol-gel method: tetrabutyl titanate was added dropwise into anhydrous ethanol, and continuously stirred for 60min to ensure complete dissolution of the tetrabutyl titanate to obtain solution A, wherein the volume ratio of tetrabutyl titanate and anhydrous ethanol in solution A is 3:5; distilled water and anhydrous ethanol were mixed according to a volume ratio of 3:16, and 68wt% concentrated nitric acid was added dropwise into the mixed solution of distilled water and anhydrous ethanol to obtain solution B, wherein the volume ratio of concentrated nitric acid and anhydrous ethanol in solution B is 1:10. Then, solution B was added dropwise into solution A, wherein the volume ratio of solution A and solution B is 20:23, and the mixture was stirred at 2000rpm for 60min to finally obtain a light yellow clear sol, i.e. the titanium dioxide sol.

[0086] (3) Preparation of the composite titanium dioxide material: the foam carbon material prepared in step (1) was immersed in the titanium dioxide sol obtained in step (2) and stirred for 60min; after being taken out and naturally air-dried, a thin coating layer was deposited on the foam carbon, and then dried in an oven at 120°C for 2h. Subsequently, it was placed in a muffle furnace for carbonization at 500°C for 2h, and then cooled to room temperature. After that, compressed air was slightly introduced to remove any pore blocking materials, to obtain the composite titanium dioxide material A1.

[0087] The actual photo of the obtained composite titanium dioxide is shown in Figure 3 The actual photo of the obtained composite titanium dioxide is shown in Figure 3It can be seen that the pores of the foam carbon are connected by holes, and the titanium dioxide is uniformly distributed on the foam carbon material.

[0088] Example 2

[0089] (1) Preparation of the foam carbon material: kelp residue, phenol and 37wt% formaldehyde solution (the mass ratio of kelp residue, phenol and 37wt% formaldehyde solution is 60:240:100) were subjected to polycondensation reaction at 70°C for 2.5h to obtain a phenol formaldehyde resin. The obtained phenol formaldehyde resin was mixed with surfactant Tween-80, foaming agent n-hexane and curing agent 37wt% hydrochloric acid (wherein the mass of Tween-80 is 10% of the mass of the phenol formaldehyde resin, the mass of n-hexane is 3% of the mass of the phenol formaldehyde resin, and the mass of hydrochloric acid is 6% of the mass of the phenol formaldehyde resin), and then put into an autoclave and foamed at 150°C for 2h to obtain a cured foam. The cured foam was mixed with ZnCl2 (the mass ratio of the cured foam and ZnCl2 is 1:3), and then subjected to carbonization treatment under N2 protection at a temperature rising rate of 15°C / min to 1000°C for 2h. After the carbonization treatment, the carbonized product was washed with 1mol / L hydrochloric acid solution and deionized water in sequence, and then placed in an oven for drying for 24h to obtain the foam carbon material.

[0090] (2) Preparation of the titanium dioxide sol by sol-gel method: tetrabutyl titanate was added dropwise into anhydrous ethanol, and stirring was continued for 30min to ensure complete dissolution of the tetrabutyl titanate to obtain solution A, wherein the volume ratio of tetrabutyl titanate to anhydrous ethanol in solution A is 3:5; distilled water and anhydrous ethanol were mixed in a volume ratio of 3:16, and 68wt% concentrated nitric acid was added dropwise into the mixed solution of distilled water and anhydrous ethanol to obtain solution B, wherein the volume ratio of concentrated nitric acid to anhydrous ethanol in solution B is 3:20. Then, solution B was added dropwise into solution A, wherein the volume ratio of solution A to solution B is 20:23, and the mixture was stirred at 2000rpm for 30min to finally obtain a light yellow clear sol, i.e. the titanium dioxide sol.

[0091] (3) Preparation of the composite titanium dioxide material: the foam carbon material prepared in step (1) was immersed in the titanium dioxide sol and stirred for 60min; after being taken out and naturally air-dried, a thin coating layer was deposited on the foam carbon, which was dried in an oven at 120°C for 2h. Then, it was placed in a muffle furnace for carbonization at 600°C for 2h, and after being cooled to room temperature, compressed air was slightly introduced to remove any pore blockage, to obtain the composite titanium dioxide material A2.

[0092] Example 3

[0093] (1) Preparation of the foam carbon material: Laminaria residue, phenol and 37wt% formaldehyde aqueous solution (the mass ratio of Laminaria residue, phenol and 37wt% formaldehyde aqueous solution is 60:240:100) were subjected to polycondensation reaction at 70°C for 2.5h to obtain a phenol-formaldehyde resin. The obtained phenol-formaldehyde resin was mixed with surfactant Tween-80, foaming agent n-hexane and curing agent 37wt% hydrochloric acid (wherein the mass of Tween-80 is 10% of the mass of the phenol-formaldehyde resin, the mass of n-hexane is 3% of the mass of the phenol-formaldehyde resin, and the mass of hydrochloric acid is 6% of the mass of the phenol-formaldehyde resin), and then put into an autoclave and foamed at 150°C for 2h to obtain a cured foam. The cured foam was mixed with ZnCl2 (the mass ratio of the cured foam and ZnCl2 is 1:3), and then subjected to carbonization treatment under N2 protection at a temperature rising rate of 5°C / min to 700°C for 2h. After the carbonization treatment, the carbonized product was washed with 1mol / L hydrochloric acid solution and deionized water in sequence, and then dried in an oven for 24h to obtain the foam carbon material.

[0094] (2) Preparation of the titanium dioxide sol by sol-gel method: Tetrabutyl titanate was added dropwise into anhydrous ethanol, and continuously stirred for 60min to ensure complete dissolution of the tetrabutyl titanate to obtain solution A, wherein the volume ratio of tetrabutyl titanate to anhydrous ethanol in solution A is 3:5; distilled water and anhydrous ethanol were mixed in a volume ratio of 3:16, and 68wt% concentrated nitric acid was added dropwise into the mixed solution of distilled water and anhydrous ethanol to obtain solution B, wherein the volume ratio of concentrated nitric acid to anhydrous ethanol in solution B is 1:10. Then, solution B was added dropwise into solution A, wherein the volume ratio of solution A to solution B is 20:23, and the mixture was stirred at 2000rpm for 30min to finally obtain a light yellow clear sol, i.e. the titanium dioxide sol.

[0095] (3) Preparation of the composite titanium dioxide material: The foam carbon material prepared in step (1) was immersed in the titanium dioxide sol and stirred for 60min; after being taken out and naturally air-dried, a thin coating layer was deposited on the foam carbon, which was dried in an oven at 120°C for 2h. Then, it was placed in a muffle furnace and carbonized at 400°C for 2h, and after being cooled to room temperature, compressed air was slightly introduced to remove any pore blocking materials to obtain the composite titanium dioxide material A3.

[0096] Example 4

[0097] (1) Preparation of the foam carbon material: Laminaria residue, phenol and 37wt% formaldehyde aqueous solution (the mass ratio of Laminaria residue, phenol and 37wt% formaldehyde aqueous solution is 60:240:100) were subjected to polycondensation reaction at 70°C for 2.5h to obtain a phenol-formaldehyde resin. The obtained phenol-formaldehyde resin was mixed with surfactant Tween-80, foaming agent n-hexane and curing agent 37wt% hydrochloric acid (wherein the mass of Tween-80 is 10% of the mass of the phenol-formaldehyde resin, the mass of n-hexane is 3% of the mass of the phenol-formaldehyde resin, and the mass of hydrochloric acid is 6% of the mass of the phenol-formaldehyde resin), and then put into an autoclave and foamed at 150°C for 2h to obtain a cured foam. The cured foam was mixed with ZnCl2 (the mass ratio of the cured foam and ZnCl2 is 1:3), and then subjected to carbonization treatment at 700°C for 2h under N2 protection at a temperature increasing rate of 5°C / min. After the carbonization treatment, the carbonized product was washed with 1mol / L hydrochloric acid and deionized water in sequence, and then dried in an oven for 24h to obtain the foam carbon material.

[0098] (2) Preparation of the titanium dioxide sol by sol-gel method: Tetrabutyl titanate was added dropwise into anhydrous ethanol, and stirring was continued for 60min to ensure complete dissolution of the tetrabutyl titanate to obtain solution A, wherein the volume ratio of tetrabutyl titanate to anhydrous ethanol in solution A is 3:5; distilled water and anhydrous ethanol were mixed in a volume ratio of 3:16, and 68wt% concentrated nitric acid was added dropwise into the mixed solution of distilled water and anhydrous ethanol to obtain solution B, wherein the volume ratio of concentrated nitric acid to anhydrous ethanol in solution B is 1:10. Then, solution B was added dropwise into solution A, wherein the volume ratio of solution A to solution B is 20:23, and the mixture was stirred at 2000rpm for 40min to finally obtain a light yellow clear sol, i.e. the titanium dioxide sol.

[0099] (3) Preparation of the composite titanium dioxide material: The foam carbon material prepared in step (1) was immersed in the titanium dioxide sol and stirred for 60min; after being taken out and naturally air-dried, a thin coating layer was deposited on the foam carbon, which was dried in an oven at 120°C for 2h. Then, it was placed in a muffle furnace and carbonized at 400°C for 2h, and after being cooled to room temperature, compressed air was slightly introduced to remove any pore blocking materials to obtain the composite titanium dioxide material A4.

[0100] Example 5

[0101] (1) Preparation of foamed carbon material: Kelp residue, phenol and 37wt% formaldehyde aqueous solution (mass ratio of kelp residue, phenol and 37wt% formaldehyde aqueous solution is 60:240:100) were subjected to polycondensation reaction at 70℃ for 2.5h to obtain phenolic resin. The obtained phenolic resin was added to surfactant Tween-80, foaming agent n-hexane and curing agent 37wt% hydrochloric acid (wherein, the mass of Tween-80 is 10% of the mass of phenolic resin, the mass of n-hexane is 3% of the mass of phenolic resin, and the mass of hydrochloric acid is 6% of the mass of phenolic resin) and placed in an autoclave, and foamed at 150℃ for 2h to obtain cured foam. Cured foam was mixed with ZnCl2 (mass ratio of cured foam to ZnCl2 was 1:3), and carbonized at 500℃ for 2 hours under N2 protection using a programmed temperature rise rate of 5℃ / min. After carbonization, the carbonized product was washed sequentially with 1mol / L hydrochloric acid solution and deionized water. After washing, the product was dried in an oven for 24 hours to obtain foamed carbon material.

[0102] (2) Preparation of titanium dioxide sol by sol-gel method: Tetrabutyl titanate was added dropwise to anhydrous ethanol and stirred continuously for 60 min to ensure complete dissolution of tetrabutyl titanate, resulting in solution A, in which the volume ratio of tetrabutyl titanate to anhydrous ethanol was 3:5; distilled water and anhydrous ethanol were mixed at a volume ratio of 3:16, and 68wt% concentrated nitric acid was added dropwise to the mixture of distilled water and anhydrous ethanol, resulting in solution B, in which the volume ratio of concentrated nitric acid to anhydrous ethanol was 1:10. Then, solution B was added dropwise to solution A, where the volume ratio of solution A to solution B was 20:23, and the mixture was stirred at 2000 rpm for 40 min, finally yielding a pale yellow clear sol, i.e., titanium dioxide sol.

[0103] (3) Preparation of composite titanium dioxide material: The foamed carbon material prepared in step (1) was immersed in titanium dioxide sol and stirred for 60 min; after being taken out and air-dried naturally, a thin coating was deposited on the foamed carbon and dried in an oven at 120°C for 2 h. Then it was placed in a muffle furnace at 500°C for 2 h for carbonization. After cooling to room temperature, compressed air was slightly introduced to remove any pore blockages, and composite titanium dioxide material A5 was obtained.

[0104] Example 6

[0105] Replace the kelp residue with wakame residue, otherwise the same as in Example 1.

[0106] Example 7

[0107] The difference from Example 1 is that the surfactant Tween-80 is replaced with nonylphenol, otherwise it is the same as Example 1.

[0108] Example 8

[0109] The difference from Example 1 is that the surfactant Tween-80 is replaced by sodium dodecyl sulfate, and the others are the same as Example 1.

[0110] Example 9

[0111] The difference from Example 1 is that the surfactant Tween-80 is replaced by dihydroxy propylene-ethylene oxide copolyether, and the others are the same as Example 1.

[0112] Example 10

[0113] The difference from Example 1 is that the active agent zinc chloride is replaced by potassium hydroxide, and the others are the same as Example 1.

[0114] Example 11

[0115] The difference from Example 1 is that the active agent zinc chloride is replaced by iron phthalocyanine, and the others are the same as Example 1.

[0116] Comparative Example 1

[0117] (1) Preparation of foamed carbon material: Laminaria residue, phenol and 37wt% formaldehyde aqueous solution (the mass ratio of Laminaria residue, phenol and 37wt% formaldehyde aqueous solution is 60:240:100) were subjected to polycondensation reaction at 70℃ for 2.5h to obtain a phenol formaldehyde resin. The foaming agent n-hexane and the curing agent 37wt% hydrochloric acid (wherein the mass of n-hexane is 3% of the mass of the phenol formaldehyde resin, and the mass of hydrochloric acid is 6% of the mass of the phenol formaldehyde resin) were added to the obtained phenol formaldehyde resin and put into an autoclave for foaming at 120℃ for 2h to obtain a cured foam. The cured foam was carbonized by heating to 700℃ at a heating rate of 5℃ / min under N2 protection for 2h. After carbonization, the carbonized product was washed with 1mol / L hydrochloric acid solution and deionized water in sequence. After washing, it was placed in an oven for drying for 24h to obtain a foamed carbon material.

[0118] (2) Preparation of titanium dioxide sol by sol-gel method: tetrabutyl titanate was added dropwise into anhydrous ethanol, and stirring was continued for 60min to ensure complete dissolution of tetrabutyl titanate to obtain solution A, the volume ratio of tetrabutyl titanate and anhydrous ethanol in solution A was 3:5; distilled water and anhydrous ethanol were mixed in a volume ratio of 3:16, and 68wt% concentrated nitric acid was added dropwise into the mixed solution of distilled water and anhydrous ethanol to obtain solution B, the volume ratio of concentrated nitric acid and anhydrous ethanol in solution B was 1:10. Then, solution B was added dropwise into solution A, wherein the volume ratio of solution A and solution B was 20:23, and the mixture was stirred at 2000rpm for 40min to finally obtain a light yellow clear sol, i.e. titanium dioxide sol.

[0119] (3) Preparation of the composite titanium dioxide material: the foam carbon material prepared in step (1) was immersed in the titanium dioxide sol for stirring for 60 min. After taking out and natural air drying, a thin coating layer was deposited on the foam carbon, which was dried in an oven at 120°C for 2 h. Then it was placed in a muffle furnace for carbonization at 500°C for 2 h. After cooling to room temperature, slight compressed air was introduced to remove any pore blockage, to obtain the composite titanium dioxide material D1.

[0120] Comparative Example 2

[0121] (1) Preparation of the foam carbon material: kelp residue, phenol and 37wt% formaldehyde aqueous solution (the mass ratio of kelp residue, phenol and 37wt% formaldehyde aqueous solution was 60:240:100) were subjected to polycondensation reaction at 70°C for 2.5 h to obtain a phenol-formaldehyde resin. The obtained phenol-formaldehyde resin was mixed with a surfactant Tween-80, a foaming agent n-hexane and a curing agent 37wt% hydrochloric acid (wherein the mass of Tween-80 was 10% of the mass of the phenol-formaldehyde resin, the mass of n-hexane was 3% of the mass of the phenol-formaldehyde resin, and the mass of hydrochloric acid was 6% of the mass of the phenol-formaldehyde resin), and then the mixture was placed in an autoclave and foamed at 150°C for 2 h to obtain a cured foam. The cured foam was mixed with ZnCl2 (the mass ratio of the cured foam to ZnCl2 was 1:3), and then subjected to carbonization treatment under N2 protection by temperature programming at a temperature increasing rate of 5°C / min to 700°C for 2 h. After carbonization treatment, the carbonized product was washed with 1 mol / L hydrochloric acid solution and deionized water in sequence, and then was placed in an oven for drying for 24 h to obtain a foam carbon material.

[0122] (2) Preparation of the titanium dioxide sol by sol-gel method: tetrabutyl titanate was added dropwise into anhydrous ethanol, and stirring was continued for 60 min to ensure complete dissolution of tetrabutyl titanate. 68wt% concentrated nitric acid was added dropwise into the mixture under vigorous stirring for 40 min to obtain a titanium dioxide sol, wherein the volume ratio of tetrabutyl titanate to anhydrous ethanol was 3:5, and the volume ratio of concentrated nitric acid to anhydrous ethanol was 1:15.

[0123] (3) Preparation of the composite titanium dioxide material: the foam carbon material prepared in step (1) was immersed in the titanium dioxide sol obtained in step (2) for stirring for 60 min. After taking out and natural air drying, a thin coating layer was deposited on the foam carbon, which was dried in an oven at 120°C for 2 h. Then it was placed in a muffle furnace for carbonization at 500°C for 2 h. After cooling to room temperature, slight compressed air was introduced to remove any pore blockage, to obtain the composite titanium dioxide material D2.

[0124] Comparative Example 3

[0125] The phenol-formaldehyde resin was replaced by a commercially available phenol-formaldehyde resin (water-soluble phenol-formaldehyde resin 9003-35-4), and other conditions were the same as in Example 1, to obtain a catalyst D3.

[0126] Comparative Example 4

[0127] The difference from Example 1 is that the surfactant Tween-80 is replaced by bile salt, and the others are the same as Example 1 to obtain catalyst D4.

[0128] Comparative Example 5

[0129] The difference from Example 1 is that no activator zinc chloride is added, and the others are the same as Example 1 to obtain catalyst D5.

[0130] Comparative Example 6

[0131] The difference from Example 1 is that the activator zinc chloride is replaced by phosphoric acid, and the others are the same as Example 1 to obtain catalyst D6.

[0132] Test Example

[0133] 1. Physical property test

[0134] The physical properties of the foamed carbon materials obtained in the examples and comparative examples were tested, as shown in Table 1.

[0135] Table 1 Physical properties of foamed carbon photocatalysts obtained in the examples and comparative examples

[0136]

[0137]

[0138] As can be seen from Table 1, the photocatalysts prepared in the examples have a lighter texture, a smaller bulk density, and good light penetration ability, which increases their light utilization ability for visible light. Dark reaction (adsorption) and experimental results show that the adsorption effects of different photocatalysts on antibiotics are A1>A10>A4>A11>A5>A3>A6>A2>A8>A7>A9; D3>D1>D4>D2>D6>D5.

[0139] 2. SEM

[0140] The composite titanium dioxide material obtained in Example 1 was observed by scanning electron microscope.

[0141] Figure 4 The SEM pictures of the composite titanium dioxide material A1 obtained in Example 1 at different magnifications, from Figure 4 It can be seen that the obtained composite titanium dioxide material A1 is mainly composed of irregular five or six face penetrating holes. The nano-TiO2 is well adhered to the foamed carbon, and the rich micropores and large surface area are beneficial to the photocatalytic effect.

[0142] 3. Degradation test

[0143] 3.1 Degradation of ofloxacin at different pH

[0144] The commonly used antibiotic in aquaculture, ofloxacin, was used as the research object. The antibiotic solution with an initial concentration of 30 mg / L was subjected to photodegradation in simulated aquaculture wastewater. The pH of the antibiotic solution was adjusted to 3-9 using NaOH or HCl, 100 mg of the composite titanium dioxide material A1 obtained in Example 1 was added, the mixed system was placed in a xenon lamp (300 W, filter wavelength greater than 400 nm) for 30 min of irradiation at room temperature, 3 mL of sample was taken at certain time intervals, the supernatant was filtered through a 0.45 μm filter membrane after centrifugation, and the concentration was determined by liquid chromatography. The results are shown in Figure 5 Figure 5 The degradation effect of the composite titanium dioxide material A1 obtained in Example 1 on ofloxacin at different pH and the degradation effect of the catalyst D5 obtained in Comparative Example 5 on ofloxacin at pH 9 are shown in Figure 5 It can be seen that under acidic conditions, the photocatalyst has poor removal effect on ofloxacin, while under neutral and alkaline conditions, the removal efficiency is significantly increased, and the degradation activity of the seaweed residue composite titanium dioxide material can be effectively exerted.

[0145] 3.2 Degradation of sulfamethoxazole at different pH

[0146] The commonly used antibiotic in aquaculture, ofloxacin, was used as the research object. The antibiotic solution with an initial concentration of 30 mg / L was subjected to photodegradation in simulated aquaculture wastewater. The pH of the antibiotic solution was adjusted to 3-9 using NaOH or HCl, 100 mg of the composite titanium dioxide material A1 obtained in Example 1 was added, the mixed system was placed in a xenon lamp (300 W, filter wavelength greater than 400 nm) for 30 min of irradiation at room temperature, 3 mL of sample was taken at certain time intervals, the supernatant was filtered through a 0.45 μm filter membrane after centrifugation, and the concentration was determined by liquid chromatography. The results are shown in Figure 6 Figure 6 The degradation effect of the composite titanium dioxide material A1 obtained in Example 1 on ofloxacin at different pH and the degradation effect of the catalyst D5 obtained in Comparative Example 5 on ofloxacin at pH 9 are shown in Figure 6 It can be seen that under dark reaction conditions, the foam carbon material has a certain adsorption effect on sulfamethoxazole due to its own pore structure. After 30 min of visible light degradation, sulfamethoxazole has been almost completely degraded, and the removal rate can be as high as nearly 100%.

[0147] 4. Recycling experiment

[0148] ​​In order to explore the practical application potential of the composite titanium dioxide material, the reaction stability of the photocatalyst is evaluated by assessing the degradation performance of the antibiotic (ofloxacin) in four consecutive cycles. 100 mg of the composite titanium dioxide material A1 obtained in Example 1 is dispersed in a 30 mg / L antibiotic solution (pH = 9) for 20 min in the dark to achieve an adsorption-desorption equilibrium state between the composite titanium dioxide material and the pollutant molecules, and then the suspension is further exposed to a visible light source for a period of time to detect the removal performance of the prepared composite titanium dioxide material on the antibiotic. After the equilibrium, the sample is stirred and washed, and then reused in the next three cycles, and the results are shown in Figure 7 . Figure 7 The degradation antibiotic cycle experiment diagram of the composite titanium dioxide material A1 obtained in Example 1 can be seen from Figure 7 After four cycles, the photocatalyst still has good stability and has a wide market application potential.

[0149] 5. Bonding force characterization

[0150] After four cycles, the composite titanium dioxide material is tested by XRD, and the results are shown in Figure 8 , Figure 8 The XRD spectrum of the composite titanium dioxide material A1 obtained in Example 1 after four cycles can be seen from Figure 8 After the cycle experiment, the characteristic peaks of the anatase and rutile crystal phases of TiO2 on the example A1, the characteristic diffraction peak values of the anatase phase mainly appear at 25.2°, 38.0°, 48.1°, 54.9°, 63.6°, 75.2°, and the existence of the anatase phase plays an important role in the degradation of organic pollutants. It is shown that the loaded titanium dioxide photocatalyst is not detached, indicating that the prepared photocatalyst has good bonding.

[0151] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a foamed carbon material, characterized in that, Includes the following steps: A condensation reaction was carried out by mixing seaweed residue, phenol and formaldehyde aqueous solution to obtain a phenolic resin. The phenolic resin, surfactant, foaming agent and curing agent are mixed and foamed to obtain cured foam. The cured foam and activator are mixed and then carbonized to obtain the foamed carbon material. The concentration of the formaldehyde aqueous solution is 20-40 wt%, and the mass ratio of the seaweed residue, phenol and formaldehyde aqueous solution is 40-70:220-260:80-120. The polycondensation reaction is carried out at a temperature of 60–80°C for 2–3 hours. The foaming temperature is 120–180°C, and the time is 1–4 hours.

2. The preparation method according to claim 1, characterized in that, The surfactant includes one or more of nonionic surfactants, anionic surfactants, fatty acids, coethers, and polyether-siloxane polymers; The curing agent includes hydrochloric acid, wherein the mass fraction of the hydrochloric acid is 20-40%; The foaming agent includes n-hexane; The surfactant comprises 5-15% of the mass of the phenolic resin. The mass of the foaming agent is 2-5% of the mass of the phenolic resin; The mass of the curing agent is 1 to 10% of the mass of the phenolic resin.

3. The preparation method according to claim 1, characterized in that, The activator includes one or more of zinc chloride, potassium hydroxide, and ferrocyanine. The mass ratio of the cured foam to the activator is 1-5:1-5.

4. The preparation method according to claim 1 or 3, characterized in that, The carbonization treatment temperature is 500–1000℃, and the holding time is 1–5h; the carbonization treatment atmosphere includes nitrogen, and the heating rate to the carbonization treatment temperature is 1–20℃ / min.

5. The foamed carbon material prepared by the preparation method according to any one of claims 1 to 4, characterized in that, The light transmittance of the foamed carbon material is 2.5–18%, and the bulk density is 0.05–1.5 g / cm³. 3 .

6. A composite catalyst material, characterized in that, It includes a carrier and a catalytically active component attached to the carrier, wherein the carrier is the foamed carbon material of claim 5.

7. The composite catalyst material according to claim 6, characterized in that, The catalytically active components include titanium dioxide, bismuth molybdate, bismuth oxybromide, cobalt tetroxide, or zinc oxide.

8. The composite catalyst material according to claim 7, characterized in that, When the catalytically active component is titanium dioxide, the composite catalyst material is capable of photocatalytically degrading antibiotics, including one or more of tetracycline antibiotics, sulfonamide antibiotics, and quinolone antibiotics.

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