A bamboo knot carbonized material for solar evaporation of water and a preparation method thereof

Abstract

The application discloses a kind of bamboo knot section carbonized material for solar evaporation of water and preparation method thereof, with forestry waste bamboo knot section as raw material, according to the geographical latitude of use area, the inclination angle of section bamboo ring is ground, and the concave upper surface is formed with bamboo partition, and is carbonized treatment etc.;With the large amount of axial passage and small amount of transverse passage of bamboo knot section as water transport matrix, get the solar evaporation material floating on the surface of liquid water, can efficiently repeat desalination of seawater.The application is driven by solar energy;Inclined bamboo ring and bamboo partition form concave upper surface, realize the full absorption of sunlight;Upper surface with carbonized thickness, realize high light-heat conversion efficiency and heat concentration;Matrix is natural bamboo, with good hydrophilicity, low thermal conductivity and other advantages;Stable structure, can cope with high salinity aqueous solution, high solar radiation, wind, rain, snow and other adverse conditions;Solve the problem of waste of forestry waste bamboo knot section.

Description

TECHNICAL FIELD

[0001] The present application relates to a bamboo joint section carbonized material for solar evaporation of water and a preparation method thereof, and belongs to the technical field of energy material preparation. BACKGROUND

[0002] Due to the rapid growth of the world population, the scarcity of fresh water resources has gradually become an important global environmental problem. According to the statistics of the United Nations, the global demand for fresh water increases by about 1% per year, and will rise to 20% to 30% in 2050. Although three-quarters of the earth's surface is covered with water, 97.5% of which is sea water (salt water) that cannot be directly drunk by humans, so it is a challenge to obtain fresh water resources from sea water. The existing research often uses reverse osmosis membrane method and thermal distillation method to obtain fresh water, but the former uses high-cost permeation membrane, and the latter uses non-renewable fossil energy. Therefore, it is urgent to find a low-energy consumption method for preparing fresh water.

[0003] The solar evaporation of water technology makes full use of solar energy resources and water resources, which are the two most abundant resources on earth, and is environmentally friendly. The traditional solar evaporation of water system mainly includes an upper layer and a lower layer structure: the upper layer is a light-absorbing material that realizes photo-thermal conversion under solar radiation; the lower layer is a substrate that provides a channel for water transport. However, the existing research on the preparation process of the lower layer substrate is complex and has high cost, which restricts commercial application, and the existing solar evaporation of water system has the problems of being unable to realize wide-band light absorption, low solar energy utilization rate, and low evaporation efficiency; the upper layer light-absorbing material is mostly a planar structure, and in high-latitude areas, the angle between the light-absorbing material and the sunlight is large at all times within a natural day except at noon, resulting in low solar radiation absorption efficiency. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a bamboo joint section carbonized material for solar evaporation of water, which uses forestry waste bamboo joint sections as raw materials, has a wide source, low cost, large specific surface area, and high wide-band light absorption efficiency, improves the evaporation efficiency, and enables the removal of heavy metal cations such as Pb, Cd, and Cu during water transport, and can be simply ground and carbonized to float on the surface of liquid water.

[0005] Meanwhile, the application provides a preparation method of the bamboo knot part carbonized material for solar evaporation of water, the upper surface of the carbonized material prepared by the method is a modified carbonized layer, higher light-heat conversion efficiency can be achieved, and because the thermal conductivity of the natural bamboo is low, the heat can be stored in the carbonized layer, avoiding loss to the lower layer substrate, meanwhile, the cellulose functional groups of the bamboo knot part and the electrostatic adsorption effect of the metal cations are utilized to make the metal organic framework (MOFs) material grow in situ on the cavity wall of the conduit of the bamboo knot part, the hydrogen bond density is reduced, the evaporation enthalpy is reduced, and the evaporation efficiency is doubled.

[0006] To solve the above technical problems, the technical scheme adopted by the application is:

[0007] A preparation method of a bamboo knot part carbonized material for solar evaporation of water, comprising the following steps:

[0008] Step 1, using the forestry waste bamboo knot part as raw material, performing cleaning treatment;

[0009] Step 2, performing grinding treatment on the inclined angle of the knot part bamboo ring, and forming a concave upper surface together with the bamboo ring;

[0010] Step 3, soaking the bamboo knot part into a mixed solution of 1-2 mol / L sodium chloroacetate and 15-20% w / v sodium hydroxide for at least 1 hour, then washing with deionized water, then soaking into a solution prepared by mixing Zn(NO)3, methanol and deionized water with a mass ratio of 1.2:10:1.5 for at least 24 hours, then adding methyl imidazole MeIm and soaking for at least 24 hours, the adding amount of methyl imidazole MeIm is 5.5 times the amount of Zn(NO)3, then vacuum drying for at least 24 hours, then soaking into a mixed solution of tetramethyl piperidyl oxyl free radical TEMPO, dopamine hydrochloride and deionized water with a mass ratio of 10:5:2 for at least 24 hours, and drying for at least 24 hours;

[0011] Step 4, performing carbonization treatment on the concave upper surface of the bamboo by local high temperature, to obtain a primary carbonized material;

[0012] Step 5, preparing an isoplasma metal salt into a mixed solution, and soaking the primary carbonized material into the mixed solution to obtain a carbonized material.

[0013] In step 1, the axial height of the bamboo knot part is 20-30 mm, that is, the bamboo ring is 10-15 mm upward and downward.

[0014] In step 1, the cleaning treatment is: washing and removing the dust on the surface of the bamboo knot part by using deionized water or 2% w / v sodium hydroxide solution; removing the dust in the internal channel of the bamboo knot part by using ultrasonic waves, the ultrasonic frequency is 100-200 W, and the ultrasonic time is 10-30 min.

[0015] In step 2, the grinding treatment is as follows: for low latitude regions, i.e. the equator to 30 degrees north latitude and the equator to 30 degrees south latitude, the inclined angle of the joint bamboo ring grinding treatment is 10-25 degrees;

[0016] For middle latitude regions, i.e. 30 degrees north latitude to 60 degrees north latitude and 30 degrees south latitude to 60 degrees south latitude, the inclined angle of the joint bamboo ring grinding treatment is 25-40 degrees;

[0017] For high latitude regions, i.e. 60 degrees north latitude to 90 degrees north latitude and 60 degrees south latitude to 90 degrees south latitude, the inclined angle of the joint bamboo ring grinding treatment is 40-55 degrees.

[0018] In step 3, the temperature of the vacuum drying is 55-75 degrees Celsius, and the vacuum degree is 0.075-0.1 MPa; the drying temperature is 55-75 degrees Celsius.

[0019] In step 4, the local high temperature process is as follows: spray a sodium carbonate solution with a mass concentration of 2.5-3.0% onto the concave upper surface, and the wet layer of the concave upper surface reaches 1-2 mm; use a 25 or 30 mm caliber torch, adjust the torch flame to blue, adjust the flame length to 180-200 mm, maintain a uniform speed of 0.5-1.5 cm / s for 1-2 min, and the carbonization depth is 1-1.2 mm.

[0020] In step 5, the plasma metal salt includes PdCl2 or AgCl.

[0021] When the plasma metal salt is PdCl2, the following steps are included:

[0022] S01, PdCl2 and deionized water are prepared into a PdCl2 solution with a concentration of 0.01-0.02 mol / L, and 0.01-0.02 mol / L of HCl is added to prepare a mixed solution, and the volume ratio of the PdCl2 solution to HCl is 1: (1.5-2.5);

[0023] S02, the mixed solution is stirred at a temperature of 60-70 degrees Celsius for 45-75 min, and the stirring speed is 300-500 r / min;

[0024] S03, the primary carbonized material is soaked in the mixed solution at a temperature of 70-90 degrees Celsius for 1.5-2.5 h;

[0025] S04, after taking out, the surface is washed with deionized water, and dried at 25-35 degrees Celsius for 12-36 h to obtain the carbonized material;

[0026] When the plasma metal salt is AgCl, the following steps are included:

[0027] S1, SnCl2 and deionized water are prepared into a SnCl2 solution of 0.01-0.02 mol / L, and 0.01-0.02 mol / L of HCl is added to prepare a mixed solution; the volume ratio of the SnCl2 solution to HCl is 1: (1.5-2.5);

[0028] S2, the mixed solution is stirred at a temperature of 60-70 DEG C for 45-75 min, and the stirring speed is 300-500 r / min;

[0029] S3, the primary carbonized material is soaked in the mixed solution at a temperature of 70-90 DEG C for 1.5-2.5 h;

[0030] S4, after taking out, the surface is washed with deionized water, and then soaked in a 0.2-0.4 mol / L AgNO3 ammonia solution for 30-60 min, and the ammonia water concentration is 20-25%;

[0031] S5, after taking out, the surface is washed with deionized water, and is recorded as a secondary carbonized material;

[0032] S6, formaldehyde and ethanol are prepared into a solution A with a formaldehyde concentration of 0.02-0.03 mol / L, and AgNO3 and deionized water are prepared into a solution B of 0.025-0.075 mol / L, and the solution A and the solution B are mixed into a solution C with a volume ratio of 1:1;

[0033] S7, the secondary carbonized material is soaked in the solution C for 20-30 h;

[0034] S8, after taking out, the surface is washed with deionized water, and is dried at 25-35 DEG C for 12-36 h to obtain the carbonized material.

[0035] The bamboo joint carbonized material for solar evaporation of water obtained by the preparation method has an absorption rate of 95-99% in the wavelength range of 250-2500 nm.

[0036] Natural bamboo has the characteristics of light weight, high strength, multi-level and porous structure, low thermal conductivity, high hydrophilicity, etc., and is an ideal raw material for the lower layer matrix of a solar evaporation system. Existing research has prepared the lower layer matrix based on renewable materials such as mushrooms, wood chips, bamboo chips, straw, and rice straw. The bamboo joint has longitudinal and transverse fiber organization and transport organization, and has a bamboo partition. The fiber organization enhances the mechanical properties of the joint in all directions to cope with high-salinity aqueous solution, high solar radiation, wind, rain, snow and other harsh conditions; the transport organization provides a multi-level and multi-size pore structure for water transmission, improving the water transmission efficiency; the bamboo partition is an ideal site for absorbing solar radiation after carbonization treatment.

[0037] Therefore, the present application first uses forestry waste bamboo joint parts as raw materials, and through simple grinding, carbonization and other treatments, solar evaporation of water can be efficiently and stably utilized, the problems of high cost, complex process, unstable structure and low light absorption efficiency of the solar evaporation water system can be solved, and the forestry waste bamboo joint parts are fully utilized.

[0038] The present application has the following beneficial effects:

[0039] 1. The present application uses forestry waste bamboo joint parts as raw materials, which are widely available and low in cost.

[0040] 2. The upper surface of the carbonized material prepared by the present application is concave, and the inclination angle of the concave shape is determined according to the latitude of the actual use area, which can improve the absorption efficiency of sunlight.

[0041] 3. The upper surface of the carbonized material prepared by the present application is a carbonized layer, which can achieve high light-heat conversion efficiency, and because the thermal conductivity of natural bamboo is low, heat can be stored in the carbonized layer, avoiding loss to the lower layer substrate.

[0042] 4. The carbonized material prepared by the present application is based on bamboo joint parts, and the large number of axial channels and small number of transverse channels of the bamboo joint parts can improve the water transport efficiency; the large-area bamboo partition carbonized layer has high temperature, and because the transverse channels connected with the bamboo partition are few, heat is not easy to dissipate.

[0043] 5. The carbonized material prepared by the present application fully utilizes the characteristics of high dimensional stability of bamboo joint parts, and can cope with high salinity water solution, high solar radiation, wind, rain, snow and other harsh conditions.

[0044] 6. The carbonized material prepared by the present application has large specific surface area and high broadband light absorption efficiency, which improves the evaporation efficiency and enables the removal of heavy metal cations such as Pb, Cd and Cu in the process of water transport, and through simple grinding, carbonization and other treatments, it can float on the surface of liquid water and be used for solar evaporation of water.

[0045] The present application provides a kind of bamboo section carbonized material preparation method for solar evaporation of water.The present application uses forestry waste bamboo section as raw material, according to the geographical latitude of use area, the grinding of the inclined angle of section bamboo ring is carried out, the concave upper surface is formed with bamboo partition, and carbonization treatment is carried out etc.;With the large amount of axial channel and small amount of transverse channel of bamboo section as water transport matrix, solar evaporation material floating on the surface of liquid water is obtained, and seawater can be efficiently and repeatedly desalinated.The present application uses solar energy as driving force;Inclined bamboo ring and bamboo partition form concave upper surface, realize the full absorption of sunlight;The upper surface with carbonized thickness realizes high light-heat conversion efficiency and heat concentration;Matrix is natural bamboo, with good hydrophilicity, low thermal conductivity and other advantages;Stable structure can cope with high salinity aqueous solution, high solar radiation, wind, rain and snow and other adverse conditions;Solve the problem of waste of forestry waste bamboo section. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is the light absorption efficiency diagram of outer edge bamboo ring after grinding treatment and without grinding treatment;

[0047] Figure 2 is the schematic diagram of different inclined angle grinding treatment of the bamboo section of the present application;

[0048] Figure 3 is an example of the bamboo section carbonized material of the present application for solar evaporation of water. DETAILED DESCRIPTION

[0049] The present application will be further described below in conjunction with the drawings.

[0050] Example 1

[0051] A preparation method of a bamboo section carbonized material for solar evaporation of water, comprising the following steps:

[0052] Step 1, using forestry waste bamboo section as raw material, washing treatment is carried out;The axial height of bamboo section is 20mm, i.e. 10mm upward and downward of bamboo partition;Washing treatment is: using deionized water to wash and remove dust on the surface of bamboo section;Using ultrasonic to remove dust in the internal channel of bamboo section, ultrasonic frequency is 100W, and ultrasonic time is 10min;

[0053] Step 2, the inclined angle of section bamboo ring is ground, and the concave upper surface is formed with bamboo partition;

[0054] Step 3, soaking the bamboo joint part into a mixed solution of 1 mol / L sodium chloroacetate and 15% w / v sodium hydroxide for 1 hour, then rinsing with deionized water, soaking into a solution prepared by mixing Zn(NO)3, methanol and deionized water in a mass ratio of 1.2:10:1.5 for 24 hours, then adding methyl imidazole MeIm and soaking for 24 hours, the amount of methyl imidazole MeIm added is 5.5 times the amount of Zn(NO)3, and then vacuum drying for 24 hours at a temperature of 55°C and a vacuum degree of 0.075 MPa; then soaking in a mixed solution of tetramethylpiperidyl oxyl radical TEMPO, dopamine hydrochloride and deionized water in a mass ratio of 10:5:2 for 24 hours, and drying for 24 hours at a temperature of 55°C;

[0055] Step 4, carbonizing the concave upper surface of the bamboo material by local high temperature to obtain a primary carbonized material; the local high temperature process is as follows: spraying a sodium carbonate solution with a mass concentration of 2.5% on the concave upper surface, the wet layer of the concave upper surface reaching 1 mm; using a 25 mm caliber torch, adjusting the torch flame to blue, adjusting the flame length to 180 mm, maintaining a uniform speed of 0.5 cm / s for 1 min, and the carbonization depth being 1 mm, to obtain a carbonized material mainly with micropores, the specific surface area increasing from 250 m 2 / g to 1780 m 2 / g;

[0056] Step 5, preparing a mixed solution of plasma metal salt, and soaking the primary carbonized material in the mixed solution to obtain a carbonized material; the plasma metal salt is PdCl2, including the following steps:

[0057] S01, preparing a PdCl2 solution of 0.01 mol / L by mixing PdCl2 and deionized water, and then adding 0.01 mol / L HCl to prepare a mixed solution, the volume ratio of the PdCl2 solution to HCl being 1:1.5;

[0058] S02, stirring the mixed solution at a temperature of 60°C for 45 min at a stirring speed of 300 r / min;

[0059] S03, soaking the primary carbonized material in the mixed solution at a temperature of 70°C for 1.5 h;

[0060] S04, rinsing the surface with deionized water after taking out, and drying at 25°C for 12 h to obtain the carbonized material.

[0061] The low-temperature plasma modification of the carbonized material in this embodiment excites, dissociates and ionizes the surface molecules of the carbonized material, forms micropores and etching grooves on the surface of the carbon material to increase the surface energy, and exhibits a broadband light absorption of 99% in the entire measurement wavelength range. The broadband light is in a wavelength range of 250-2500 nm.

[0062] The absorption rates of raw bamboo are approximately 50% at 500nm, 10% at 1000nm, 35% at 1500nm, 50% at 2000nm, and 65% at 2500nm; while carbonized bamboo modified with plasma metal can consistently maintain an absorption rate of 99% in the wavelength range of 250-2500nm.

[0063] The method described in this embodiment yields a carbonized bamboo joint material for solar-powered water evaporation.

[0064] In this embodiment, the lower part of the bamboo joint is a water-conducting layer:

[0065] 1) After ultrasonic treatment at a frequency of 100W for 10 minutes, the outer bamboo ring of the bamboo node is open from top to bottom, thus removing the original lipids, silicates, tyloses, inclusions, dust and other impurities, forming a water transport channel; while the inner bamboo septa of the bamboo node are relatively closed, so the duct ports are sealed, making the thermal conductivity of this part lower than that of the outer bamboo ring, allowing heat to be concentrated at the bamboo septa and preventing heat loss to the outer bamboo ring and the water below.

[0066] 2) Utilizing the electrostatic adsorption effect between cellulose functional groups and metal cations, metal-organic framework (MOF) materials are grown in situ on the cavity wall of the conduit, reducing hydrogen bond density and thus lowering the enthalpy of vaporization, thereby increasing the evaporation efficiency by nearly double (from 1.4 kg·m³). -2 ·h -1 Increased to 2.6 kg·m -2 ·h -1 Furthermore, it enables the removal of heavy metal cations such as Pb, Cd, and Cu during the water transport process.

[0067] like Figure 1 As shown, the upper part of the bamboo joint in this embodiment is a light-absorbing layer. The outer bamboo ring is ground and tilted according to the latitude of the actual use area, forming a concave upper surface connected with the inner bamboo partition. Taking Beijing, China (39°56'N) as an example, the corresponding tilt angle can be 30°. Compared with the flat upper surface, the concave upper surface material can achieve a light absorption efficiency of over 90% from 9:00 AM to 3:00 PM, while the flat upper surface material can only achieve a light absorption efficiency of over 90% from 11:00 AM to 1:00 PM. The former maintains a high light absorption efficiency for three times longer than the latter.

[0068] like Figure 2 As shown, schematic diagrams of grinding treatments at different tilt angles of bamboo nodes are provided. Figure 2 It can be seen that the tilt angle of the grinding process is determined by the latitude of the actual area of ​​use, including:

[0069] For low latitude regions, i.e. equator to 30° north latitude and equator to 30° south latitude regions, the inclination angle of the node section bamboo ring grinding treatment is 10°~ 25°;

[0070] For middle latitude regions, i.e. 30° north latitude to 60° north latitude and 30° south latitude to 60° south latitude regions, the inclination angle of the node section bamboo ring grinding treatment is 25°~ 40°;

[0071] For high latitude regions, i.e. 60° north latitude to 90° north latitude and 60° south latitude to 90° south latitude regions, the inclination angle of the node section bamboo ring grinding treatment is 40°~ 55°.

[0072] Figure 3 Examples of the bamboo node section carbonized material for solar evaporation of water are provided, as shown in Figure 3 The insulating material 2 and the container 4 are both polymer foams with waterproof, heat-insulating and other properties, and polyethylene foam or silicone rubber foam is selected.

[0073] Example 2

[0074] A preparation method of a bamboo node section carbonized material for solar evaporation of water, comprising the following steps:

[0075] Step 1, forestry waste bamboo node sections are used as raw materials for cleaning treatment; the axial height of the bamboo node section is 30mm, i.e. 15mm upward and downward from the bamboo node; the cleaning treatment is: using 2% w / v sodium hydroxide solution to wash and remove the dust on the surface of the bamboo node section; using ultrasonic waves to remove the dust in the internal channel of the bamboo node section, the ultrasonic frequency is 200W, and the ultrasonic time is 30min;

[0076] Step 2, the node section bamboo ring is subjected to grinding treatment of an inclination angle, and the concave upper surface is formed together with the bamboo node; for low latitude regions, i.e. the equator region, the inclination angle of the node section bamboo ring grinding treatment is 10°;

[0077] For middle latitude regions, i.e. 30° north latitude and 30° south latitude regions, the inclination angle of the node section bamboo ring grinding treatment is 25°;

[0078] For high latitude regions, i.e. 60° north latitude and 60° south latitude regions, the inclination angle of the node section bamboo ring grinding treatment is 40°.

[0079] Step 3, the bamboo joint part is soaked in a mixed solution of 2 mol / L sodium chloroacetate and 20% w / v sodium hydroxide for 2 hours, then washed with deionized water, and then soaked in a solution prepared by mixing Zn(NO)3, methanol and deionized water in a mass ratio of 1.2:10:1.5 for 30 hours, and then soaked for 36 hours after adding methyl imidazole MeIm, the amount of methyl imidazole MeIm added is 5.5 times the amount of Zn(NO)3, and then vacuum dried for 28 hours, the vacuum drying temperature is 75℃, and the vacuum degree is 0.1 MPa; then soaked in a mixed solution of tetramethylpiperidyl oxyl radical TEMPO, dopamine hydrochloride and deionized water in a mass ratio of 10:5:2 for 25 hours, and dried for 30 hours, the drying temperature is 75℃;

[0080] Step 4, the concave upper surface of the bamboo material is carbonized by local high temperature to obtain a primary carbonized material; the local high temperature process is as follows: spraying a sodium carbonate solution with a mass concentration of 3.0% on the concave upper surface, the wet layer of the concave upper surface reaches 2mm; using a 30mm caliber torch, adjusting the flame of the torch to blue, adjusting the flame length to 200mm, maintaining a uniform speed of 1.5cm / s for 2min, the carbonization depth is 1.2mm, and a carbonized material mainly composed of micropores is obtained;

[0081] Step 5, the plasma metal salt is prepared into a mixed solution, and the primary carbonized material is soaked in the mixed solution to obtain a carbonized material; the plasma metal salt is PdCl2, including the following steps:

[0082] S01, PdCl2 and deionized water are prepared into a 0.02mol / L PdCl2 solution, and then 0.02mol / L HCl is added to prepare a mixed solution, the volume ratio of the PdCl2 solution to HCl is 1:2.5;

[0083] S02, the mixed solution is stirred at a temperature of 70℃ for 75min, and the stirring speed is 500r / min;

[0084] S03, the primary carbonized material is soaked in the mixed solution at a temperature of 90℃ for 2.5h;

[0085] S04, after taking out, the surface is washed with deionized water, and dried at 35℃ for 36h to obtain a carbonized material.

[0086] In this embodiment, the low-temperature plasma modified carbonized material excites, dissociates and ionizes the surface molecules of the carbonized material, forms micropores and etching grooves on the surface of the carbon material to increase the surface energy, and exhibits a broadband light absorption of 95% in the entire wavelength range of 250-2500nm.

[0087] Example 3

[0088] A preparation method of a bamboo knot section carbonized material for solar evaporation of water, comprising the following steps:

[0089] Step 1, using forestry waste bamboo knot section as raw material, cleaning treatment; the axial height of the bamboo knot section is 24mm, i.e. 12mm upward and 12mm downward; the cleaning treatment is: using deionized water to wash and remove the dust on the surface of the bamboo knot section; using ultrasonic wave to remove the dust in the internal channel of the bamboo knot section, the ultrasonic frequency is 150W, and the ultrasonic time is 20min;

[0090] Step 2, grinding treatment of the inclined angle of the knot section bamboo ring to form a concave upper surface together with the bamboo partition; for low latitude regions, i.e. the regions of north latitude 30° and south latitude 30°, the inclined angle of the grinding treatment of the knot section bamboo ring is 25°;

[0091] for middle latitude regions, i.e. the regions of north latitude 60° and south latitude 60°, the inclined angle of the grinding treatment of the knot section bamboo ring is 40°;

[0092] for high latitude regions, i.e. the regions of north latitude 90° and south latitude 90°, the inclined angle of the grinding treatment of the knot section bamboo ring is 55°;

[0093] Step 3, soaking the bamboo knot section into a mixed solution of 1.5mol / L sodium chloroacetate and 18%w / v sodium hydroxide for 3 hours, then washing with deionized water, and then soaking into a solution prepared from Zn(NO)3, methanol and deionized water with a mass ratio of 1.2:10:1.5 for 48 hours, and then soaking for 24 hours after adding methyl imidazole MeIm, the adding amount of methyl imidazole MeIm is 5.5 times of the amount of Zn(NO)3, and then vacuum drying for 26 hours, the vacuum drying temperature is 65℃, and the vacuum degree is 0.09MPa; then soaking in a mixed solution of tetramethylpiperidinooxy free radical TEMPO, dopamine hydrochloride and deionized water with a mass ratio of 10:5:2 for 48 hours, and drying for 48 hours, the drying temperature is 60℃;

[0094] Step 4, carbonizing the concave upper surface of the bamboo by local high temperature to obtain a primary carbonized material; the local high temperature process is: spraying a sodium carbonate solution with a mass concentration of 2.5% on the concave upper surface, the wet layer of the concave upper surface reaches 1.5mm; using a 25mm caliber torch, adjusting the flame of the torch to blue, adjusting the flame length to 190mm, maintaining a uniform speed of 1.0cm / s for 1.5min, the carbonization depth is 1.1mm, and a carbonized material mainly composed of micropores is obtained;

[0095] Step 5, preparing a mixed solution of plasma metal salt, and soaking the primary carbonized material in the mixed solution to obtain a carbonized material; the plasma metal salt of the embodiment is AgCl, which needs to be reduced to Ag by Sn 2+ reduction of Ag +, comprising the following steps:

[0096] S1, SnCl2 and deionized water are prepared into a SnCl2 solution of 0.01 mol / L, and 0.01 mol / L of HCl is added to prepare a mixed solution; the volume ratio of the SnCl2 solution to HCl is 1:1.5;

[0097] S2, the mixed solution is stirred at a temperature of 60°C for 45 min, and the stirring speed is 300 r / min;

[0098] S3, the primary carbonized material is soaked in the mixed solution at a temperature of 70°C for 1.5 h;

[0099] S4, after taking out, the surface is washed with deionized water, and then soaked in a 0.2 mol / L AgNO3 ammonia solution for 30 min, and the ammonia water concentration is 20%;

[0100] S5, after taking out, the surface is washed with deionized water, and is recorded as a secondary carbonized material;

[0101] S6, formaldehyde and ethanol are prepared into a solution A with a formaldehyde concentration of 0.02 mol / L, and AgNO3 and deionized water are prepared into a solution B of 0.025 mol / L, and the solution A and the solution B are mixed into a solution C with a volume ratio of 1:1;

[0102] S7, the secondary carbonized material is soaked in the solution C for 20 h;

[0103] S8, after taking out, the surface is washed with deionized water, and is dried at 25°C for 12 h to obtain a carbonized material.

[0104] The low-temperature plasma modified carbonized material in this embodiment excites, dissociates and ionizes the molecules on the surface of the carbonized material, forms micropores and etching grooves on the surface of the carbon material to increase the surface energy, and exhibits a broadband light absorption of 98% in the entire wavelength measurement range of 250-2500 nm.

[0105] The bamboo joint carbonized material for solar evaporation of water obtained by the preparation method of this embodiment.

[0106] Example 4

[0107] The difference between this embodiment and Example 3 is only that:

[0108] The plasma metal salt of this embodiment is AgCl, which needs to be reduced to Ag by Sn 2+ Reduction of Ag + , comprising the following steps:

[0109] S1, SnCl2 and deionized water are prepared into a SnCl2 solution of 0.02 mol / L, and 0.02 mol / L of HCl is added to prepare a mixed solution; the volume ratio of the SnCl2 solution to HCl is 1:2.5;

[0110] S2, the mixed solution is stirred at a temperature of 70°C for 75 min, and the stirring speed is 500 r / min;

[0111] S3, the primary carbonized material is soaked in the mixed solution at a temperature of 90°C for 2.5 h;

[0112] S4, after being taken out, the surface is washed with deionized water, and then soaked in a 0.4 mol / L AgNO3 ammonia solution for 60 min, and the ammonia water concentration is 25%;

[0113] S5, after being taken out, the surface is washed with deionized water, and is recorded as a secondary carbonized material;

[0114] S6, formaldehyde and ethanol are prepared into a solution A with a formaldehyde concentration of 0.03 mol / L, and AgNO3 and deionized water are prepared into a solution B of 0.075 mol / L, and solution A and solution B are mixed into solution C at a volume ratio of 1:1;

[0115] S7, the secondary carbonized material is soaked in solution C for 30 h;

[0116] S8, after being taken out, the surface is washed with deionized water, and is dried at 35°C for 36 h to obtain a carbonized material.

[0117] In this embodiment, the low-temperature plasma modified carbonized material forms micropores and etching grooves on the surface of the carbon material to increase the surface energy, and exhibits a broadband light absorption of 99% in the entire wavelength range of 250-2500 nm.

[0118] Example 5

[0119] The difference between this embodiment and Example 3 is only that:

[0120] The plasma metal salt of this embodiment is AgCl, which needs to be reduced to Ag by Sn 2+ Reduction of Ag + , comprising the following steps:

[0121] S1, SnCl2 and deionized water are prepared into a SnCl2 solution of 0.015 mol / L, and 0.02 mol / L of HCl is added to prepare a mixed solution; the volume ratio of the SnCl2 solution to HCl is 1:2;

[0122] S2, the mixed solution is stirred at a temperature of 65°C for 60 min, and the stirring speed is 400 r / min;

[0123] S3, immerse the primary carbonized material in the mixed solution at a temperature of 80°C for 2h;

[0124] S4, after taking out, rinse the surface with deionized water, then immerse in 0.3mol / L AgNO3ammonia solution for 40min, the ammonia concentration is 25%;

[0125] S5, after taking out, rinse the surface with deionized water, and mark as secondary carbonized material;

[0126] S6, prepare a solution A with formaldehyde and ethanol, the formaldehyde concentration is 0.025mol / L, prepare a solution B with AgNO3and deionized water, the concentration is 0.05mol / L, mix solution A and solution B with a volume ratio of 1:1 to form solution C;

[0127] S7, immerse the secondary carbonized material in solution C for 25h;

[0128] S8, after taking out, rinse the surface with deionized water, dry at 30°C for 24h, and obtain the carbonized material.

[0129] The low-temperature plasma modified carbonized material in this embodiment forms micropores and etching grooves on the surface of the carbon material to increase the surface energy, and exhibits a wideband light absorption of 97% in the entire 250-2500nm measurement wavelength range.

[0130] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A method for preparing a bamboo node carbonized material for solar evaporation of water, characterized by, The method comprises the following steps: Step 1, cleaning the bamboo joint part of forestry waste; Step 2, grinding the bamboo joint part at an inclined angle to form a concave upper surface together with the bamboo joint part; Step 3, soaking the bamboo joint part in a mixed solution of 1-2 mol / L sodium chloroacetate and 15-20% w / v sodium hydroxide for at least 1 hour, then rinsing with deionized water, soaking in a solution prepared from Zn(NO)3, methanol and deionized water with a mass ratio of 1.2:10:1.5 for at least 24 hours, then adding methyl imidazole and soaking for at least 24 hours, and then vacuum drying for at least 24 hours, and then soaking in a mixed solution of tetramethylpiperidinyloxy free radical, dopamine hydrochloride and deionized water with a mass ratio of 10:5:2 for at least 24 hours, and then drying for at least 24 hours; Step 4, carbonizing the concave upper surface by local high temperature to obtain a primary carbonized material; Step 5, preparing a mixed solution of plasma metal salt, and soaking the primary carbonized material in the mixed solution to obtain a carbonized material; In step 4, the local high temperature process is as follows: spraying a sodium carbonate solution with a mass concentration of 2.5-3.0% on the concave upper surface, so that the wet layer of the concave upper surface is 1-2 mm; using a 25 or 30 mm caliber torch, adjusting the flame of the torch to blue, adjusting the flame length to 180-200 mm, and keeping the torch at a uniform speed of 0.5-1.5 cm / s to roast the concave upper surface for 1-2 min, and the carbonization depth is 1-1.2 mm; In step 5, the plasma metal salt comprises PdCl2 or AgCl; When the plasma metal salt is PdCl2, the following steps are included: S01, preparing a PdCl2 solution with a concentration of 0.01-0.02 mol / L from PdCl2 and deionized water, then adding 0.01-0.02 mol / L HCl to prepare a mixed solution, and the volume ratio of the PdCl2 solution to HCl is 1:(1.5-2.5); S02, stirring the mixed solution at a temperature of 60-70℃ for 45-75 min at a stirring speed of 300-500 r / min; S03, soaking the primary carbonized material in the mixed solution at a temperature of 70-90℃ for 1.5-2.5 h; S04, rinsing the surface with deionized water after taking out, and drying at 25-35℃ for 12-36 h to obtain the carbonized material; When the plasma metal salt is AgCl, the following steps are included: S1, preparing a SnCl2 solution with a concentration of 0.01-0.02 mol / L from SnCl2 and deionized water, then adding 0.01-0.02 mol / L HCl to prepare a mixed solution, and the volume ratio of the SnCl2 solution to HCl is 1:(1.5-2.5); S2, stirring the mixed solution at a temperature of 60-70℃ for 45-75 min at a stirring speed of 300-500 r / min; S3, soaking the primary carbonized material in the mixed solution at a temperature of 70-90℃ for 1.5-2.5 h; S4, rinsing the surface with deionized water after taking out, and drying at 25-35℃ for 12-36 h to obtain the carbonized material. S4, after taking out, rinsing the surface with deionized water, and then soaking in 0.2-0.4 mol / L AgNO3 ammonia solution for 30-60 min; S5, after taking out, rinsing the surface with deionized water, and then soaking in 0.2-0.4 mol / L AgNO3 ammonia solution for 30-60 min; S6, preparing a solution A with formaldehyde and ethanol, in which the concentration of formaldehyde is 0.02-0.03 mol / L, and preparing a solution B with AgNO3 and deionized water, in which the concentration of AgNO3 is 0.025-0.075 mol / L, and then mixing solution A and solution B in a volume ratio of 1:1 to obtain solution C; S7, soaking the secondary carbonized material in solution C for 20-30 h; S8, after taking out, rinsing the surface with deionized water, and then drying at 25-35℃ for 12-36 h to obtain the carbonized material; In step 1, the axial height of the bamboo node part is 20-30 mm, i.e. 10-15 mm upward and 10-15 mm downward. In step 1, the cleaning treatment is: using deionized water or 2% w / v sodium hydroxide solution to wash and remove the dust on the surface of the bamboo node part; using ultrasonic waves to remove the dust in the internal channel of the bamboo node part, the ultrasonic frequency being 100-200 W and the ultrasonic time being 10-30 min.

2. The production method according to claim 1, characterized by, In step 3, the temperature of vacuum drying is 55-75℃, and the vacuum degree is 0.075-0.1 MPa; the drying temperature is 55-75℃.

3. The bamboo node part carbonized material for solar evaporation of water obtained by the preparation method according to any one of claims 1-2.

4. The bamboo node carbonized material for solar evaporation of water according to claim 3, characterized in that, The absorption rate of the carbonized material in the wavelength range of 250-2500 nm is 95-99%. The absorption rate of the carbonized material in the wavelength range of 250-2500 nm is 95-99%.

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