Photo-thermal conversion body, preparation method and interfacial evaporation device

Abstract

The application belongs to the technical field of wastewater treatment, and particularly relates to a photo-thermal conversion body, a preparation method, and an interfacial evaporation device. The photo-thermal conversion body is prepared by the following preparation method: step 1: preparing corn cob charcoal loaded with CuO and Fe2O3; step 2: placing the corn cob charcoal prepared in step 1 in a sodium alginate solution, pouring into a mold, and performing freezing, freeze-drying, and cross-linking treatment to obtain corn cob charcoal aerogel loaded with CuO and Fe2O3; and step 3: taking the corn cob charcoal aerogel after hydrolysis of polydimethylsiloxane and single-face modification of the corn cob charcoal aerogel, so that one side of the corn cob charcoal aerogel is a hydrophobic interface, and the other side is a hydrophilic interface, to prepare the photo-thermal conversion body. The interfacial evaporation device has the advantages of simple operation, low cost, high solar energy utilization rate, effective removal of organic matter, high-efficiency desalination, and the like, and has a wide application prospect in the field of phenol-containing and salt-containing wastewater treatment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a photothermal conversion body, a preparation method and an interfacial evaporation device. BACKGROUND

[0002] The world's supply of fresh water is decreasing, and there are great challenges in meeting the growing demand for water resources. Various mature technologies, including ion exchange, electrodialysis, reverse osmosis, nanofiltration membranes, etc., have been developed into technologies for purifying seawater and industrial wastewater. However, the practical application of these technologies is limited by the high cost of equipment, high cost and significant energy consumption (5-8 kW / m -3 ) of the equipment. Solar energy, as an inexhaustible and inexhaustible green renewable energy, provides a large amount of radiant energy to the earth. Solar interfacial evaporation driven by it can be used for seawater desalination and wastewater treatment, ensuring fresh water safety while reducing the use of renewable energy. Therefore, effective use of solar energy to obtain fresh water is an alternative and key solution to the trade-off between water-energy relations.

[0003] However, as the research on solar interfacial evaporation devices gradually deepens, a single solar evaporator has been difficult to meet the actual demand. Generally, industrial wastewater contains salt, heavy metals, organic matter, and even volatile organic compounds (VOCs) such as phenol. In the process of rapid evaporation, the increase in temperature inevitably produces a new problem, that is, volatile organic compounds will be enriched in the condensed water along with water vapor. Therefore, there are still challenges in realizing comprehensive condensate purification and removal of high-concentration pollutants in the evaporation residue for the solar interfacial evaporation device. In addition to volatile organic compounds, industrial wastewater contains a large amount of inorganic salts. With the progress of the evaporation process, salt accumulation appears on the surface of the evaporator, affecting the performance of the evaporator. In addition, the evaporation efficiency relying on the absorption of solar energy into heat energy is limited, especially under weak light conditions, the weakening of solar radiation will directly affect the evaporation rate of the device.

[0004] Therefore, it is a technical problem that needs to be solved by those skilled in the art whether an interfacial evaporation device that can both treat seawater desalination and industrial wastewater and does not appear salt accumulation in use can be provided. SUMMARY

[0005] The application provides a photothermal conversion body and a preparation method and an interfacial evaporation device, and corn cob charcoal loaded with CuO and Fe2O3 is used as a photothermal conversion body material, and after treatment, an aerogel with a light-trapping hydrophobic upper layer capable of enhancing light trapping and a hydrophilic lower layer capable of effectively degrading pollutants is obtained, and salt particles can be continuously dissolved in the lower water body, so that salt accumulation on the photothermal conversion layer is avoided; meanwhile, a cup-in-cup light concentrator is constructed by arranging a reflector, so that the solar radiation intensity is improved, and the operation cost in wastewater treatment is reduced.

[0006] A preparation method of a photothermal conversion body, comprising the following steps:

[0007] Step 1: biomass corn cob powder is taken and placed in a CuCl2 and FeCl3 solution, NaOH is added, and then carbonization treatment is performed to obtain corn cob charcoal loaded with CuO and Fe2O3;

[0008] Step 2: the corn cob charcoal prepared in step 1 is taken and placed in a sodium alginate solution, and is poured into a mold and subjected to freezing, freeze-drying and crosslinking treatment to obtain corn cob charcoal aerogel loaded with CuO and Fe2O3;

[0009] Step 3: after hydrolysis, polydimethylsiloxane is used to modify one side of the corn cob charcoal aerogel, so that one side of the corn cob charcoal aerogel is a hydrophobic interface, and the other side is a hydrophilic interface, and a photothermal conversion body is prepared.

[0010] Further, in step 1, after NaOH is added, a suspension liquid containing corn cob, Cu(OH)2 and Fe(OH)3 is obtained, and after centrifugal washing to neutral, a precipitate containing corn cob, Cu(OH)2 and Fe(OH)3 is obtained, and after carbonization treatment of the precipitate, washing and drying, corn cob charcoal loaded with CuO and Fe2O3 is obtained.

[0011] Further, in step 1, the mass ratio of the corn cob charcoal to the sum of the masses of CuO and Fe2O3 is 2-6, and the mass ratio of CuO to Fe2O3 is 0.5-2, and the carbonization treatment temperature is 400-700 DEG C, and the time is 30-120 min.

[0012] Further, in step 2, the crosslinking agent used in the crosslinking treatment is a CaCl2 solution, and the carbon content of the corn cob charcoal aerogel is 1-5 wt%.

[0013] Further, in step 2, the mold is a flat cylinder with an inner diameter of 20 mm.

[0014] Further, the concentration of the hydrolyzed polydimethylsiloxane is 2-6 wt%.

[0015] A photothermal conversion body is prepared by the above preparation method.

[0016] An interfacial evaporation device comprises the photothermal conversion body.

[0017] An interfacial evaporation device comprises a shell, a transparent evaporation cover in the shape of a cone is connected to the top opening of the shell, a water collecting groove is arranged at the top opening of the shell, the photothermal conversion body is arranged in the shell and below the water collecting groove, the hydrophobic interface of the photothermal conversion body faces upward, and the hydrophilic interface of the photothermal conversion body is connected with a water absorbing member.

[0018] Further, a heat insulation layer is further connected in the shell, a through hole is formed in the heat insulation layer, the photothermal conversion body is supported on the heat insulation layer, one end of the water absorbing member is connected with the photothermal conversion body, and the other end of the water absorbing member penetrates through the through hole and is immersed in the water to be treated.

[0019] Further, a base is further arranged in the shell, a plurality of reflectors are fixed on the base, the reflector surfaces of the plurality of reflectors all face the hydrophobic interface of the photothermal conversion body, and the plurality of reflectors are arranged around the photothermal conversion body and are inclined toward the photothermal conversion body.

[0020] Further, a water outlet pipe is communicated with the water collecting groove, and the water outlet end of the water outlet pipe penetrates through the shell.

[0021] Further, the interfacial evaporation device further comprises a water collecting bottle, and the water outlet end of the water outlet pipe is communicated with or oppositely arranged with the water collecting bottle.

[0022] Further preferably, the transparent evaporation cover is made of quartz, the heat insulation layer is made of polystyrene foam, the water absorbing member is a degreasing cotton strip, the base is made of polystyrene foam, and the thickness of the reflector is 1 mm.

[0023] A water treatment method is provided, the interfacial evaporation device is taken, water to be treated is added into the shell, hydrogen peroxide solution is added into the water to be treated, the angle of the reflector is adjusted, solar energy is focused on the photothermal conversion body through reflection of the reflector, and the concentration of the hydrogen peroxide solution is 10-50 mmol·L -1 .

[0024] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0025] 1、The photo-thermal conversion body obtained from the corn cob charcoal uniformly loaded with CuO and Fe2O3 is a Janus structure aerogel, the photo-thermal conversion body has a photo-thermal hydrophobic upper layer capable of enhancing light trapping and a hydrophilic lower layer capable of effectively degrading pollutants, and exhibits high solar energy absorption (82.52%) and efficient heat management. Specifically, under one-fold solar radiation intensity (1 Sun), the evaporation rate is 2.21 kg·m -2 ·h -1 , the evaporation efficiency is 90.76%, and the maximum surface temperature is 45.2℃; for 10 mg·L -1 of phenol solution, the removal rates of phenol in the condensed water and the evaporation residue are 99.82% and 80.0%, respectively.

[0026] 2、The photo-thermal conversion body provided by the application belongs to a Fenton-like catalyst material, can catalyze the Fenton-like reaction of hydrogen peroxide to remove volatile organic compounds (phenol) while converting solar light into heat energy, has the advantages of simple preparation and strong universality, avoids the problems of catalyst recovery and harmful waste in homogeneous Fenton, and has good development prospects in the field of wastewater treatment.

[0027] 3、The photo-thermal conversion body provided by the application adopts a Janus structure of hydrophobic / hydrophilic, can continuously dissolve the salt particles crystallized in the evaporation process in the lower water body in addition to efficient heat management, and solves the problem of salt precipitation of the photo-thermal conversion body in the prior art. The salt ion removal rate of the interfacial evaporation device of the application can reach 99.99%.

[0028] 4、In order to improve the solar radiation intensity, the photo-thermal conversion body of the application increases a light condensing structure in the transparent evaporation cover, i.e. includes multiple pairs of two parallel reflectors. After adding the light condensing structure, the solar radiation intensity received by the photo-thermal conversion body is increased by nearly 2.1 times, and the evaporation rate reaches 4.02 kg·m -2 ·h -1 . BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Fig. 1 is a structural schematic diagram of an interfacial evaporation device according to an embodiment of the application;

[0030] Figure 2 Fig. 3 is a schematic diagram of evaporation rate and surface temperature before and after adding reflectors for testing the evaporation performance of the embodiment of the application;

[0031] Figure 3 Fig. 5 is a schematic diagram of the purification results of pollutants in simulated phenol-containing and salt-containing wastewater and actual coal washing wastewater during wastewater treatment according to the embodiment of the application;

[0032] Figure 4 Fig. 7 is a column chart of the desalination results of simulated seawater by the interfacial evaporation device according to the embodiment of the application;

[0033] Figure 5 A column chart of running stability test results of the interfacial evaporation device of the embodiment of the present application;

[0034] Figure 6 A comparison chart of salting-out test results of the interfacial evaporation devices of Example 1 and Example 4 of the present application.

[0035] The figure is marked: 1-transparent evaporation cover, 2-water collecting tank, 3-outlet pipe, 4-photothermal conversion body, 5-heat insulation layer, 6-water absorbing part, 7-water collecting bottle, 8-base, 9-mirror. DETAILED DESCRIPTION

[0036] In order to more clearly show the technical solutions and advantages of the present application, the following specific embodiments will be described and introduced in detail. The following embodiments are only a part of the embodiments of the present application, not all the embodiments, and therefore the scope of the present application is not limited by the following embodiments. The materials and reagents mentioned in the present application can be obtained by commercial channels if not otherwise specified; the solvents mentioned in the present application are deionized water if not otherwise specified; the mass ratio mentioned in the present application is the mass ratio if not otherwise specified; the described embodiments are all carried out in an indoor environment with a temperature of 20°C if not otherwise specified.

[0037] Example 1

[0038] The present embodiment provides a photothermal conversion body, and the preparation method is as follows:

[0039] Step 1: preparation of corn cob carbon loaded with CuO and Fe2O3 by chemical co-precipitation method

[0040] First, the biomass corn cob is crushed and sieved, then added to a CuCl2 and FeCl3 solution, and a suspension containing corn cob, Cu(OH)2 and Fe(OH)3 is obtained by adding NaOH. The suspension is centrifuged and washed to neutral to obtain a precipitate containing corn cob, Cu(OH)2 and Fe(OH)3. The precipitate is placed in an oven and dried, then carbonized at 500°C for 60 min under anaerobic conditions. The carbonized product is washed with alcohol, washed with water, and dried to obtain corn cob carbon loaded with CuO and Fe2O3. The mass ratio of the corn cob carbon to the mass of the metal oxides (CuO and Fe2O3) is 4.5, and the mass ratio of CuO to Fe2O3 is 1.5.

[0041] Step 2: preparation of sodium alginate carbon aerogel

[0042] The corn cob char obtained in step 1 is placed in a sodium alginate solution, stirred uniformly, and then poured into a mold with an inner diameter of 20 mm (flat cylinder) to undergo freezing, freeze-drying, cross-linking with a 2wt% CaCl2 solution, and freeze-drying, finally obtaining a CuO and Fe2O3-loaded corn cob char aerogel containing 5wt% of carbon;

[0043] Step 3: Preparation of photothermal conversion body 4

[0044] The concentration of the hydrolyzed polydimethylsiloxane is 5wt%, and the corn cob char aerogel is modified on one side to make one side of the corn cob char aerogel a hydrophobic interface and the other side a hydrophilic interface, thereby preparing the photothermal conversion body 4. By constructing a hydrophobic / hydrophilic interface, salt particles can be dissolved in the lower water body, avoiding the accumulation of salt on the photothermal conversion body 4. The prepared photothermal conversion body 4 is a flat cylinder and belongs to a Fenton-like catalyst material.

[0045] The photothermal conversion body prepared in Example 1 is used to prepare an interfacial evaporation device according to Example 5. Under one-fold solar radiation intensity, the detected evaporation rate is 2.21kg·m -2 ·h -1 , the evaporation efficiency is 90.76%, and the surface maximum temperature is 45.2℃; for a 10mg·L -1 phenol solution, the removal rates of phenol in the condensed water and the evaporation residue are 99.82% and 80.0%, respectively.

[0046] Example 2

[0047] The present embodiment provides a photothermal conversion body, and the preparation method is as follows:

[0048] Step 1: Preparation of CuO and Fe2O3-loaded corn cob char by chemical co-precipitation

[0049] First, the biomass corn cob is crushed and sieved, then added to a CuCl2 and FeCl3 solution, and a suspension containing corn cob, Cu(OH)2 and Fe(OH)3 is obtained by adding NaOH. The suspension is centrifuged and washed to neutral to obtain a precipitate containing corn cob, Cu(OH)2 and Fe(OH)3. The precipitate is placed in an oven and dried, then carbonized at 700℃ for 30min under anaerobic conditions. The carbonized product is washed with alcohol and water and dried to obtain CuO and Fe2O3-loaded corn cob char. The mass ratio of the corn cob char to the mass of the metal oxides (CuO and Fe2O3) is 2, and the mass ratio of CuO to Fe2O3 is 0.5.

[0050] Step 2: Preparation of sodium alginate char aerogel

[0051] The corn cob char obtained in step 1 was placed in a sodium alginate solution, stirred uniformly, and then poured into a mold with an inner diameter of 20 mm (flat cylinder) to undergo freezing, freeze-drying, cross-linking with a 2wt% CaCl2 solution, and freeze-drying, finally obtaining a CuO and Fe2O3-loaded corn cob char aerogel containing 3wt% carbon;

[0052] Step 3: Preparation of photothermal conversion body 4

[0053] The concentration of the hydrolyzed polydimethylsiloxane was 2wt%, and the corn cob char aerogel was modified on one side to make one side of the corn cob char aerogel a hydrophobic interface and the other side a hydrophilic interface, thereby preparing the photothermal conversion body 4. By constructing a hydrophobic / hydrophilic interface, salt particles can be dissolved in the lower water body, avoiding the accumulation of salt on the photothermal conversion body 4. The prepared photothermal conversion body 4 is a flat cylinder and belongs to a Fenton-like catalyst material.

[0054] The photothermal conversion body prepared in Example 2 was used to prepare an interfacial evaporation device according to Example 5. Under one-fold solar radiation intensity, the evaporation rate was 2.01 kg·m -2 ·h -1 , and the maximum surface temperature was 42.9℃; for a 10mg·L -1 phenol solution, the removal rates of phenol in the condensed water and the evaporation residue were 89.7% and 50.3%, respectively.

[0055] Example 3

[0056] The present embodiment provides a photothermal conversion body, which is prepared by the following method:

[0057] Step 1: Preparation of CuO and Fe2O3-loaded corn cob char by chemical co-precipitation

[0058] First, the biomass corn cob was crushed and sieved, then added to a CuCl2 and FeCl3 solution, and a suspension containing corn cob, Cu(OH)2 and Fe(OH)3 was obtained by adding NaOH. The suspension was centrifuged and washed until neutral to obtain a precipitate containing corn cob, Cu(OH)2 and Fe(OH)3. The precipitate was placed in an oven and dried, then carbonized at 400℃ for 120min under anaerobic conditions. The carbonized product was washed with alcohol and water and dried to obtain CuO and Fe2O3-loaded corn cob char. The mass ratio of the corn cob char to the mass of the metal oxides (CuO and Fe2O3) was 6, and the mass ratio of CuO to Fe2O3 was 2.

[0059] Step 2: Preparation of sodium alginate char aerogel

[0060] The corn cob char obtained in step 1 is placed in a sodium alginate solution, stirred uniformly, and then poured into a mold with an inner diameter of 20 mm (flat cylinder) to undergo freezing, freeze-drying, cross-linking with a 2wt% CaCl2 solution, and freeze-drying, finally obtaining a CuO and Fe2O3-loaded corn cob char aerogel containing 1wt% of carbon;

[0061] Step 3: Preparation of photothermal conversion body 4

[0062] The concentration of the hydrolyzed polydimethylsiloxane is 6wt%, and the corn cob char aerogel is modified on one side to make one side of the corn cob char aerogel a hydrophobic interface and the other side a hydrophilic interface, thereby preparing the photothermal conversion body 4. By constructing a hydrophobic / hydrophilic interface, salt particles can be dissolved in the lower water body, avoiding the accumulation of salt on the photothermal conversion body 4. The prepared photothermal conversion body 4 is a flat cylinder and belongs to a Fenton-like catalyst material.

[0063] The photothermal conversion body prepared in Example 3 is used to prepare an interfacial evaporation device according to Example 5. Under one-fold solar radiation intensity, the evaporation rate is 1.89kg·m -2 ·h -1 , and the maximum surface temperature is 42.9℃; for a 10mg·L -1 phenol solution, the removal rates of phenol in the condensed water and the evaporation residue are 88.2% and 49.4%, respectively.

[0064] Example 4

[0065] The present embodiment provides a photothermal conversion body, and the preparation method is as follows:

[0066] Step 1: Preparation of CuO and Fe2O3-loaded corn cob char by chemical co-precipitation

[0067] First, the biomass corn cob is crushed and sieved, then added to a CuCl2 and FeCl3 solution, and a suspension containing corn cob, Cu(OH)2 and Fe(OH)3 is obtained by adding NaOH. The suspension is centrifuged and washed to neutral to obtain a precipitate containing corn cob, Cu(OH)2 and Fe(OH)3. The precipitate is placed in an oven and dried, then carbonized at 500℃ for 60min under anaerobic conditions. The carbonized product is washed with alcohol and water and dried to obtain CuO and Fe2O3-loaded corn cob char. The mass ratio of the corn cob char to the mass of the metal oxides (CuO and Fe2O3) is 4.5, and the mass ratio of CuO to Fe2O3 is 1.5.

[0068] Step 2: Preparation of sodium alginate char aerogel

[0069] The corn cob char obtained in step 1 was placed in a sodium alginate solution, stirred evenly, and then poured into a mold (flat cylinder) with an inner diameter of 20 mm. After freezing, freeze drying, cross-linking with 2 wt% CaCl2 solution, and freeze drying, a corn cob char aerogel loaded with CuO and Fe2O3 was finally obtained, with a carbon content of 1 wt%.

[0070] Using the corn cob carbon aerogel prepared in Example 4 as the photothermal converter, and the interfacial evaporation device prepared in Example 5, the evaporation rate exhibited was 1.94 kg·m³ under one times the solar radiation intensity. -2 ·h -1 The highest surface temperature was 45.2℃; for 10 mg·L⁻¹ -1 The phenol removal rates in the phenol solution, condensate, and evaporation residue reached 98.4% and 63.8%, respectively.

[0071] Example 5

[0072] An interfacial evaporation device, such as Figure 1 As shown, the photothermal converter 4 prepared according to any one of the embodiments 1 to 3 includes a shell, a transparent evaporation cap 1 in the shape of a cone connected to the top opening of the shell, a water collection tank 2 provided at the top opening of the shell, the photothermal converter 4 disposed inside the shell and located below the water collection tank 2, the hydrophobic interface of the photothermal converter 4 facing upward, and a water-absorbing element 6 connected to the hydrophilic interface of the photothermal converter 4; a heat insulation layer 5 is also connected inside the shell, the heat insulation layer 5 has through holes, the photothermal converter 4 is supported on the heat insulation layer 5, one end of the water-absorbing element 6 is connected to the photothermal converter 4, and the other end passes through the through holes and is immersed in the water to be treated; a base 8 is also provided inside the shell, the base 8 is supported on the heat insulation layer 5, and a plurality of reflectors 9 are fixed on the base 8, the reflector surfaces of the plurality of reflectors 9 all facing the hydrophobic interface of the photothermal converter 4, and the plurality of reflectors 9 are arranged around the photothermal converter 4 and tilted towards the photothermal converter 4. The tilt angle is 10 to 90 degrees. A water outlet pipe 3 is connected to the water collection tank 2, and the outlet end of the water outlet pipe 3 extends out of the housing. The interface evaporation device also includes a water collection bottle 7, and the outlet end of the water outlet pipe 3 is connected to or opposite to the water collection bottle 7.

[0073] A water treatment method involves taking the aforementioned interfacial evaporation device, adding water to be treated into the shell, adding hydrogen peroxide solution to the water, and adjusting the angle of the reflector 9 so that solar energy is focused onto the photothermal converter 4 by the reflector; the concentration of the hydrogen peroxide solution is 10–50 mmol·L⁻¹. -1 More preferably, the concentration of the hydrogen peroxide solution is 20 mmol·L⁻¹. -1 .

[0074] The application principle of the interface evaporation device is as follows: the water to be treated is absorbed by the water absorption part 6 to the light-heat conversion body 4, the solar energy is reflected and focused by the reflector 9 to the light-heat conversion body 4, and the water on the light-heat conversion body is evaporated to the transparent evaporation cover 1. Since the transparent evaporation cover 1 is a conical body, the evaporated water flows into the water collecting groove 7 along the inner wall of the transparent evaporation cover 1, and flows out through the water outlet pipe 3 into the water collecting bottle 7.

[0075] Example 6

[0076] On the basis of the technical scheme of Example 5, further preferably, the number of reflectors 9 is four pairs of two parallel reflectors 9, that is, a total of eight, and the sunlight is reflected by adjusting the angle of the reflector 9 to focus the solar energy on the light-heat conversion body 4 at all times. When the horizontal angle of the reflector 9 towards the light conversion body is 30°, the solar radiation intensity received by the light-heat conversion body 4 is 2.1 Sun, which is increased by 2.1 times, and the evaporation rate reaches 4.02 kg·m -2 ·h -1 .

[0077] Example 7

[0078] On the basis of the technical scheme of Example 5, further preferably, the connection mode of the reflector 9 and the base 8 is cementing, so that the reflector 9 is supported on the base 8 at a certain angle. The number of reflectors 9 is four pairs of two parallel reflectors 9, that is, a total of eight, and the sunlight is reflected by adjusting the angle of the reflector 9 to focus the solar energy on the light-heat conversion body 4 at all times. When the horizontal angle of the reflector 9 towards the light conversion body is 0°, the solar radiation intensity received by the surface of the light-heat conversion body 4 is 1.3 sun, and the evaporation rate reaches 2.42 kg·m -2 ·h -1 .

[0079] Experimental Example 1

[0080] Light-heat conversion body 4 wettability detection experiment

[0081] The light-heat conversion body 4 prepared in Example 1 is cut to obtain the upper and lower surfaces, and is placed flat on the contact angle instrument, and water is dropped on the surface. Among them, the upper surface has excellent hydrophobicity, the contact angle is 131°, and it remains good within 10s without being absorbed; the lower surface shows excellent hydrophilicity, the contact angle is 0°.

[0082] Experimental Example 2

[0083] Light-heat conversion body 4 light absorption performance test

[0084] The light absorption of the light-heat conversion body 4 prepared in Example 1 was determined by a UV-vis-NIR spectrometer in the wavelength range of 200-2500 nm, and the light absorption rate of the light-heat conversion body 4 was 82.52%, achieving full-spectrum absorption.

[0085] Experimental Example 3

[0086] Evaporation performance test of the interface heat exchange device

[0087] The interface heat exchange device prepared in Example 1 was placed on an electronic analytical balance, and a xenon lamp light source was used to simulate sunlight. The evaporation rates under 1 Sun and under 1 Sun+ condenser were recorded, respectively, as shown in Figure 2 The evaporation rate under 1 Sun was 2.21 kg·m -2 ·h -1 , and the evaporation rate under 1 Sun+ condenser was 4.02 kg·m -2 ·h -1 .

[0088] In the evaporation performance test, an infrared imager was used to record the surface temperature change of the light-heat conversion body 4. The highest temperature on the surface of the light-heat conversion body 4 under 1 Sun was 45.2℃, and the highest temperature on the surface of the light-heat conversion body 4 under 1 Sun+ condenser was 58.7℃, which was mainly due to the high solar energy utilization rate.

[0089] Experimental Example 4

[0090] Salt resistance test of the interface heat exchange device

[0091] A 20wt% NaCl solution was used as a sample, and the interface heat exchange device prepared in Example 1 was used for evaporation treatment. The evaporation rate of the device during long-time repeated operation (1h x 6 cycles) and the surface salt crystallization change were recorded. After 6h continuous evaporation, the evaporation rate of the device remained stable, and there was no salt crystallization on the surface. At this time, the salt crystallization caused by the evaporation process was limited to the hydrophobic / hydrophilic interface, and was re-dissolved in the lower water body through the convection of the water body.

[0092] Wastewater treatment effect of the interface heat exchange device

[0093] A simulated phenol-containing and salt-containing wastewater was used as a sample, and the interface heat exchange device prepared in Example 1 was used for evaporation treatment. The phenol concentration in the water was determined according to the “Determination of Volatile Phenol in Water-4-Aminoantipyrene Spectrophotometric Method” (HJ 503-2009). The results are shown in Figure 3As shown, a) the changes in phenol concentration in condensate and evaporation residue after simulated treatment of phenol- and salt-containing wastewater, b) the UV-Vis absorption spectra of simulated dye wastewater (methylene blue) stock solution, condensate, and evaporation residue, c) the UV-Vis absorption spectra of simulated dye wastewater (Rhodamine B) stock solution, condensate, and evaporation residue, and d) the changes in organic matter concentration in actual coal washing wastewater.

[0094] like Figure 3 As shown in (a), for 10 mg·L -1 The phenol removal rates in the phenol solution, condensate, and evaporation residue reached 99.84% and 80%, respectively. Using simulated dye wastewater (methylene blue, rhodamine B) as a sample, the interfacial heat exchanger prepared in Example 1 was used for evaporation treatment. Figure 3 (b) and Rhodamine B ( Figure 3 The concentration of (c) was determined using a spectrophotometer. The effect of the wastewater treatment of this device was judged by testing the UV-Vis absorption spectra of the original liquid, the evaporated residue and the condensate.

[0095] Using actual coal washing wastewater as a sample, the interfacial heat exchanger prepared in Example 1 was used for evaporation treatment. The COD in the water was determined according to the "Determination of Chemical Oxygen Demand in Water - Dichromate Method" (HJ 828-2017). Figure 3 As shown in (d), the COD removal rates of the original coal washing wastewater and condensate after evaporation treatment can reach 83.36% and 99.75%, respectively.

[0096] Using simulated seawater with typical salinity as a sample, the interfacial heat exchanger prepared in Example 1 was subjected to evaporation treatment. Ka before and after desalination was determined by inductively coupled plasma mass spectrometry (ICP-MS). + Na + Ca 2+ and Mg 2+ Concentration changes, such as Figure 4 As shown, the concentrations of the four ions in the treated water were significantly reduced (by four orders of magnitude), far exceeding the requirements of the WHO drinking water standards.

[0097] In addition, to verify the leaching of copper and iron metal ions in this interfacial evaporation apparatus, the concentrations of copper and iron metal ions in the solution were determined by ICP-MS after 30 hours of continuous evaporation. The leaching concentrations of Cu and Fe were 3.666 ug / L and 2.952 ug / L, respectively.

[0098] Stability test

[0099] Long-term operational stability is a crucial consideration for solar interfacial evaporation technology. Therefore, a stability test was conducted on the interfacial heat exchange device prepared in Example 1. The results are as follows: Figure 5As shown, a) the change in the evaporation rate of the photothermal converter after 20 consecutive uses, and b) the change in the evaporation rate of the photothermal converter after acid, alkali and ultrasonic treatment.

[0100] like Figure 5 As shown in (a), the interface evaporation device was continuously evaporated 20 times under 1 Sun, keeping all conditions unchanged. The evaporation rate and the highest surface temperature were tested after 20 cycles. The evaporation rate remained at a stable level, and the highest temperature of the evaporation interface also remained basically unchanged, indicating that the interface evaporation device has good stability.

[0101] To verify the ability of the photothermal converter 4 to resist acid, alkali, and ultrasonic corrosion, it was subjected to acid immersion at pH=3, alkali immersion at pH=11, and ultrasonic treatment for 3 hours. The evaporation rates before and after treatment were then measured. Figure 5 As shown in (b), the evaporation rate did not change significantly before and after the treatment, indicating that the photothermal converter 4 prepared in Example 1 has good corrosion resistance and high stability.

[0102] Experimental Example 5:

[0103] Salting out detection experiment

[0104] The interfacial evaporation apparatuses prepared in Examples 1 and 4 were used to conduct surface salting-out evaporation detection experiments. Under one times the solar radiation intensity, the surface salting-out evaporation rate increased from 1.94 kg·m³ during 5 hours of continuous evaporation. -2 ·h -1 Reduced to 0.84 kg·m -2 ·h -1， The test results are as follows Figure 6 As shown, Figure 6 As shown in the images, when the corn cob carbon aerogel was modified on one side with 5 wt% polydimethylsiloxane, no obvious salt precipitation was observed on the surface after 5 hours of continuous evaporation. However, the corn cob carbon aerogel without polydimethylsiloxane modification showed salt precipitation on its surface after 5 hours of continuous evaporation. Therefore, the interfacial evaporation device prepared in Example 1 of this invention can continuously dissolve the salt particles crystallized during evaporation into the lower water layer, solving the salt precipitation problem of photothermal converters in the prior art.

[0105] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0106] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method for preparing a photothermal conversion body, characterized by: The method comprises the following steps: Step 1: Biomass corncob powder is taken and placed in a CuCl2 and FeCl3 solution, and after NaOH is added, a suspension containing corncob, Cu(OH)2 and Fe(OH)3 is obtained, and after centrifugal washing to neutral, a precipitate containing corncob, Cu(OH)2 and Fe(OH)3 is obtained, and after carbonization treatment of the precipitate, washing and drying, corncob charcoal loaded with CuO and Fe2O3 is obtained; Step 2: The corncob charcoal prepared in step 1 is taken and placed in a sodium alginate solution, and after pouring into a mold, freezing, freeze-drying and crosslinking treatment, corncob charcoal aerogel loaded with CuO and Fe2O3 is obtained; Step 3: After hydrolysis of polydimethylsiloxane, one side of the corncob charcoal aerogel is modified, so that one side of the corncob charcoal aerogel is a hydrophobic interface and the other side is a hydrophilic interface, and a photothermal conversion body is prepared.

2. The method of claim 1, wherein: In step 1, the mass ratio of the corncob charcoal to the sum of the masses of CuO and Fe2O3 is 2-6, and the mass ratio of CuO to Fe2O3 is 0.5-2, and the carbonization treatment temperature is 400-700 DEG C, and the time is 30-120 min.

3. The method of claim 1, wherein: In step 2, the crosslinking agent used in the crosslinking treatment is a CaCl2 solution, and the carbon content of the corncob charcoal aerogel is 1-5 wt%; the concentration of the hydrolyzed polydimethylsiloxane is 2-6 wt%.

4. A light-to-heat converter, characterized by: Prepared by the preparation method of any one of claims 1-3.

5. An interfacial evaporation apparatus characterized by: The photothermal conversion body of claim 4 is included.

6. The interfacial evaporation apparatus of claim 5, wherein: The interface evaporation device comprises a shell, a transparent evaporation cover in the shape of a cone is connected to the top opening of the shell, a water collecting tank is arranged at the top opening of the shell, the photothermal conversion body is arranged in the shell and below the water collecting tank, the hydrophobic interface of the photothermal conversion body faces upward, and the hydrophilic interface of the photothermal conversion body is connected to a water absorbing member.

7. The interfacial evaporation apparatus of claim 6, wherein: A heat insulation layer is further connected in the shell, a through hole is formed in the heat insulation layer, the photothermal conversion body is supported on the heat insulation layer, one end of the water absorbing member is connected to the photothermal conversion body, and the other end of the water absorbing member penetrates through the through hole and is immersed in the water to be treated.

8. The interfacial evaporation apparatus of claim 6, wherein: A base is further arranged in the shell, a plurality of reflectors are fixed on the base, the reflector surfaces of the plurality of reflectors all face the hydrophobic interface of the photothermal conversion body, and the plurality of reflectors are arranged around the photothermal conversion body and are inclined toward the photothermal conversion body.

9. The interfacial evaporation apparatus of claim 6, wherein: A water outlet pipe is communicated with the water collecting tank, and the water outlet end of the water outlet pipe penetrates through the shell; the interface evaporation device further comprises a water collecting bottle, and the water outlet end of the water outlet pipe is in communication with or oppositely arranged with the water collecting bottle.

10. A method of water treatment, characterized by: The interface evaporation device of claim 8, wherein water to be treated is added into the shell, hydrogen peroxide solution is added into the water to be treated, the angle of the reflector is adjusted, and solar energy is focused on the light-heat conversion body through the reflector; the concentration of the hydrogen peroxide solution is 10-50 mmol·L -1 .

Images