A solar interface evaporator for simultaneous desalination and degradation of organic matters, and a preparation method and application thereof

Abstract

The present application belongs to the technical field of wastewater treatment, and particularly relates to a solar interfacial evaporator for simultaneously desalinating and degrading organic matters, a preparation method and application thereof. The evaporator provided by the present application comprises the following structures: a photothermal interface with good photothermal conversion performance, a heat insulation plate and a water delivery medium with catalyst attached. The water delivery medium pumps water to the evaporation interface of the photothermal interface through capillary action, and the catalyst catalyzes the degradation of organic matters in water by hydrogen peroxide; the heat insulation plate blocks heat loss, and the heat is concentrated on the evaporation interface by using the light absorption characteristics of the photothermal material. In the photothermal process, the solar interfacial evaporator can simultaneously achieve efficient desalination and degradation of organic matters. The solar interfacial evaporator integrates multiple functions such as light absorption, water delivery, desalination and pollutant degradation, and can efficiently utilize solar energy for desalination and organic matter degradation under the synergistic action of the photothermal interface and the water delivery medium. The preparation process is simple, no additional pollution is generated, and the economic benefit is high, so that the present application can be widely applied.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, more particularly, to a solar interfacial evaporator for simultaneous desalination and degradation of organic matter, and a preparation method and application thereof. BACKGROUND

[0002] In today's industrial production and social activities, the generation of salt-containing organic wastewater has become an environmental problem that cannot be ignored. With the rapid development of many industries such as chemical industry, pharmaceutical industry, printing and dyeing industry, and food processing industry, a large amount of wastewater containing organic matter and high-concentration salt is discharged. These wastewaters are complex in composition, containing various difficult-to-degrade organic pollutants and having high salinity. Therefore, it is urgent to develop efficient, economical and environmentally friendly treatment technologies for salt-containing organic wastewater.

[0003] Interfacial evaporation driven by sustainable solar energy, as a technology that can provide clean water, is widely used. Solar interfacial evaporation can confine energy in the light-absorbing layer using a specific structure, allowing water to evaporate on the surface of the structure. It is a utilization way of converting light energy into heat energy. Pollutants, especially volatile organic pollutants, will evaporate into the condensed water along with water vapor due to their low boiling points. In the traditional solar interfacial evaporation, the catalyst is attached to the photothermal interface. When salt-containing organic wastewater is transported to the interface, it can be degraded while being desalinated, reducing the concentration of pollutants in the condensed liquid. However, the organic pollutants in the bottom liquid are not degraded. SUMMARY

[0004] The present application aims to provide a solar interfacial evaporator for simultaneous desalination and degradation of organic matter, and a preparation method and application thereof. In the present application, the catalyst is separated from the photothermal interface and attached to the water transport medium. Pollutants are degraded during transportation to the interface, and only evaporation and desalination occur at the photothermal interface. Meanwhile, the catalyst on the water transport medium catalyzes the degradation of organic matter in the bottom liquid using hydrogen peroxide, greatly reducing the concentration of pollutants in both the condensed liquid and the bottom liquid. The solar interfacial evaporator of the present application integrates light absorption, water transport, desalination, and pollutant degradation into one device, and has the advantages of being green, energy-saving, and environmentally friendly.

[0005] The present application provides a solar interfacial evaporator, which comprises a catalyst-loaded water transport medium, a heat insulation plate, and a photothermal interface with good light-heat conversion performance. The catalyst-loaded water transport medium penetrates the heat insulation plate and contacts the photothermal interface, and the photothermal interface is placed above the heat insulation plate, with the lower surface of the photothermal interface in contact with the heat insulation plate.

[0006] The preparation method of the catalyst-loaded water transport medium comprises the following steps:

[0007] (1) weigh a certain amount of FeCl3·6H2O, dissolve it in deionized water, stir it uniformly, add a certain amount of hydrochloric acid, and adjust the pH of the mixed solution to 1-5, preferably 2-3;

[0008] (2) put the water delivery medium into the mixed solution, ultrasonically remove the bubbles to fill the mixed solution inside the water delivery medium, heat it at 60-80℃ for 10-36h, and make the generated β-FeOOH firmly adhere to the water delivery medium, to obtain the water delivery medium loaded with the catalyst.

[0009] The photothermal interface is a hydrophilic material loaded with a photothermal conversion substance.

[0010] Further, the water delivery medium is one or more of a cotton core rope, dust-free paper or cotton cloth.

[0011] Further, the content of FeCl3·6H2O in the mixed solution in step (1) is 3-30g / L, preferably 10-20g / L, the concentration of hydrochloric acid is 0.001-1.2mol / L, preferably 0.01-0.1mol / L, and the ultrasonic time in step (2) is 5-60min, preferably 10-20min.

[0012] Further, the heat insulation plate is a material with low thermal conductivity, and the material is one or more of polyethylene foam, polystyrene foam or polypropylene foam.

[0013] Further, the hydrophilic material of the photothermal interface is one or more of cotton cloth, hydrogel, cotton cloth strip or melamine sponge.

[0014] Further, the photothermal conversion substance loaded on the photothermal interface is one or more of polydopamine, polypyrrole, reduced graphene oxide or multi-walled carbon nanotube, and the loading amount of the photothermal conversion substance is 1-20%, preferably 3-10%. For example, the preparation method of the cotton cloth loaded with polydopamine is as follows: dissolve hydrochloric acid dopamine in a Tris-HCl (pH=8.5) buffer solution to obtain a dopamine solution, then place the cotton cloth in the dopamine solution and heat it at 50℃ for 10h to obtain the cotton cloth loaded with polydopamine.

[0015] The application also provides a preparation method of the above-mentioned solar energy evaporator, which comprises the following steps:

[0016] Hollow the middle of the heat insulation plate, place the photothermal interface above the heat insulation plate, and make the water delivery medium loaded with the catalyst pass through the heat insulation plate to contact the photothermal interface, to obtain the solar energy interface evaporator.

[0017] The application provides the application of the above-mentioned solar energy interface evaporator or the solar energy interface evaporator prepared by the above-mentioned preparation method in the treatment of salt-containing organic wastewater. The application method comprises the following steps:

[0018] Under stirring, hydrogen peroxide is added into the salt-containing organic wastewater to form a mixed solution; the solar interface evaporator is placed in the mixed solution, and is suspended on the beaker under the support of the heat insulation plate, the lower end of the water delivery medium loaded with the catalyst is immersed in the mixed solution, and the light-heat interface is irradiated by sunlight to treat the salt-containing organic wastewater.

[0019] Further, the concentration of the hydrogen peroxide is 10-200 mM, preferably 60-100 mM; the salinity of the salt-containing organic wastewater is 0.1-5%, preferably 2-3%; the pH of the mixed solution is 2-8, preferably 2-4; and the organic pollutants are one or more of phenol, aniline, sulfamethoxazole, N,N-dimethylformamide, dye, or antibiotic.

[0020] Further, the time for the light-heat interface to be irradiated by sunlight is 3-12 hours.

[0021] In the present application, the hydrophilic material loaded with light-heat conversion substances is used as the light-heat interface, and the water delivery medium attached with the catalyst is used as the water delivery layer, so that the salt-containing organic wastewater is pumped to the light-heat interface by capillary action, and the catalyst catalyzes the degradation of the organic matter in water by hydrogen peroxide; the heat insulation plate blocks the heat loss, and the light absorption characteristics of the light-heat conversion substances concentrate the heat at the evaporation interface.

[0022] Specifically, first, the light-heat conversion substances are a kind of black compounds, which have excellent light absorption characteristics and high light-heat conversion efficiency, and can effectively absorb solar energy and convert it into heat energy; second, the cotton core rope, dust-free paper, or cotton cloth as the water delivery medium can quickly pump water to the interface; third, the catalyst β-FeOOH loaded on the water delivery medium can assist the rapid degradation of the organic matter by hydrogen peroxide.

[0023] In the light-heat process, the solar interface evaporator can realize efficient desalination while degrading the organic matter, and is especially suitable for salt-containing wastewater containing both volatile organic matter and non-volatile organic matter. The solar interface evaporator integrates light absorption, water delivery, desalination, and pollutant degradation, and can efficiently utilize solar energy for desalination and organic matter degradation under the synergistic action of the light-heat interface and the water delivery medium.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] (1) The present application aims to design a solar interface evaporator that can efficiently desalinate and simultaneously catalytically degrade organic pollutants.

[0026] (2) The present application not only reduces the salt content and pollutant concentration in the condensed water evaporated, but also greatly reduces the concentration of organic pollutants in the salt-containing organic wastewater in which the water delivery medium is located.

[0027] (3) The preparation process is simple, the instrument and equipment requirement is low, the cost is low, no additional pollution is generated, and high economic benefits are obtained, so that large-scale popularization and application can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0028] The application will be further described in combination with the drawings and examples.

[0029] Figure 1 is a schematic structure diagram of the application of the solar interface evaporator in Example 1;

[0030] Figure 2 is a comparison chart of the effects of the solar interface evaporators in Examples 1, 2, 3, 4 and 5 on desalination and degradation of organic pollutants in salt-containing organic wastewater;

[0031] Figure 3 is an effect chart of the solar interface evaporator prepared in Example 1 on cyclic treatment of salt-containing organic wastewater. DETAILED DESCRIPTION

[0032] The application will be further described in combination with the drawings and examples.

[0033] A solar interface evaporator for simultaneously desalinating and degrading organic matter, comprising a water conveying medium loaded with a catalyst, a heat insulation plate and a light-heat interface; the water conveying medium loaded with the catalyst penetrates through the heat insulation plate and is in contact with the light-heat interface, the light-heat interface is arranged above the heat insulation plate, and the lower surface of the light-heat interface is in contact with the heat insulation plate.

[0034] The preparation method of the water conveying medium loaded with the catalyst comprises the following steps:

[0035] (1) FeCl3·6H2O is dissolved in deionized water, stirred uniformly, and hydrochloric acid is added to adjust the pH of the mixed solution to 1-5;

[0036] (2) The water conveying medium is placed in the mixed solution obtained in step (1), ultrasonic degassing is performed to fill the mixed solution in the water conveying medium, and heating is performed at 60-80℃ for 10-36h, so that the generated β-FeOOH is firmly attached to the water conveying medium, and the water conveying medium loaded with the catalyst is obtained.

[0037] The light-heat interface is a hydrophilic material loaded with a light-heat conversion substance.

[0038] Example 1

[0039] A solar interfacial evaporator for simultaneous desalination and degradation of organic matter, comprising a cotton core rope loaded with β-FeOOH, a polyethylene foam heat insulation plate and cotton cloth loaded with 3% polydopamine; the cotton core rope loaded with β-FeOOH penetrates through the polyethylene foam heat insulation plate and is in contact with the cotton cloth loaded with polydopamine.

[0040] First step: 0.4g FeCl3·6H2O was weighed and dissolved in 20mL deionized water, then 10mL 0.01mol / L hydrochloric acid was added, and the mixture was stirred uniformly to obtain a mixed solution; a cotton core rope with a length of 9cm was placed in the mixed solution, ultrasonic treatment was performed for 15min, and heating was performed at 60℃ for 12h until the generated β-FeOOH was firmly attached to the cotton core rope; after washing away the β-FeOOH that was not firmly attached, drying was performed to obtain the cotton core rope loaded with β-FeOOH.

[0041] Second step: 0.12g dopamine hydrochloride was weighed and dissolved in 40mL Tris-HCl (pH=8.5) buffer solution to obtain a dopamine solution; then a cotton cloth with a diameter of 3cm was placed in the dopamine solution and heated at 50℃ for 10h to obtain black cotton cloth loaded with 3% polydopamine.

[0042] Third step: the black polydopamine cotton cloth obtained in the second step was placed in the middle of a polyethylene foam heat insulation plate with a diameter of 6cm and a thickness of 2cm; a hole with a diameter of 10mm was opened in the middle of the polyethylene foam heat insulation plate; the cotton core rope loaded with β-FeOOH penetrated through the hole, and the upper core was dispersed around and in contact with the polydopamine cotton cloth to prepare the solar interfacial evaporator.

[0043] Under stirring, hydrogen peroxide was added to a 50mL beaker containing 50mL of salt-containing organic wastewater to form a mixed solution; the solar interfacial evaporator prepared in this example was placed in the mixed solution and hung on the beaker under the support of the polyethylene foam heat insulation plate; the lower end of the cotton core rope loaded with β-FeOOH was immersed in the mixed solution, and the light-heat interface was irradiated with sunlight for 5h to treat the salt-containing organic wastewater. The concentration of hydrogen peroxide was 60mM; the salinity of the salt-containing organic wastewater was 2%; the organic pollutant was phenol, and the pH of the mixed solution was 3.

[0044] The concentrations of organic pollutants phenol in the bottom liquid and the condensed liquid, and the conductivities of salt pollutants before and after removal were determined by high performance liquid chromatography and conductivity meter, and the degradation rate and desalination rate were calculated.

[0045] Example 2

[0046] The difference from Example 1 is that 0.8g FeCl3·6H2O was weighed and dissolved in 20mL deionized water in the first step, and the rest was consistent with Example 1.

[0047] Example 3

[0048] The difference from Example 1 is that the cotton core rope is replaced by dust-free paper, and the rest is the same as Example 1.

[0049] Example 4

[0050] The difference from Example 1 is that the cotton core rope is not loaded with catalyst β-FeOOH, and the rest is the same as Example 1.

[0051] Example 5

[0052] The difference from Example 1 is that the cotton cloth is not loaded with light-heat conversion material polydopamine, and the rest is the same as Example 1.

[0053] Figure 2 The effect comparison chart of the solar interface evaporator prepared in Examples 1, 2, 3, 4, 5 on desalination and degradation of organic pollutants in salt-containing organic wastewater is shown in Figure 2 It can be seen that the solar interface evaporator in the present application has the effects of simultaneous desalination and degradation of organic matter, the desalination rate reaches 98.6%, and the degradation effect of organic pollutants phenol in the bottom liquid and the condensate reaches 92.7% and 95.1%.

[0054] Example 6

[0055] The β-FeOOH-loaded cotton core rope and the polydopamine-loaded cotton cloth in Example 1 are soaked in deionized water for 1h and then dried, and a regenerated solar interface evaporator is prepared therefrom. The solar interface evaporator is prepared according to the method of the third step, the middle of the polyethylene foam heat insulation plate is opened, the light-heat interface (polydopamine-loaded cotton cloth) is placed above the heat insulation plate, the water conveying medium (β-FeOOH-loaded cotton core rope) attached with the catalyst passes through the heat insulation plate to contact with the light-heat interface, and a regenerated solar interface evaporator is obtained. Under stirring, hydrogen peroxide is added to a 50mL beaker containing 50mL of salt-containing organic wastewater to form a mixed solution; the regenerated solar interface evaporator is placed in the mixed solution and suspended on the beaker under the support of the polyethylene foam heat insulation plate, the lower end of the β-FeOOH-loaded cotton core rope is immersed in the mixed solution, and the light-heat interface is irradiated with sunlight for 5 hours to treat the salt-containing organic wastewater. The concentration of hydrogen peroxide is 60mM; the salinity of the salt-containing organic wastewater is 2%; the organic pollutant is phenol, and the pH of the mixed solution is 3. The above operation is repeated for 5 cycles, and the concentration of the organic pollutant phenol in the bottom liquid and the condensate is determined by high performance liquid chromatography and conductivity meter, and the degradation rate and the desalination rate are calculated, and the results are shown in Figure 3 .

[0056] Figure 3 The effect chart for recycling treatment of salt-containing organic wastewater is shown in Figure 3It can be seen that the solar interface evaporator prepared in Example 1 still exhibits high efficiency of desalination and degradation of organic pollutants after 5 cycles, thereby indicating that the solar interface evaporator of the application has good stability and regenerability.

[0057] For any person skilled in the art, many possible variations and modifications, or equivalent embodiments of equivalent changes can be made to the technical solutions of the application by using the technical contents disclosed above without departing from the scope of the technical solutions of the application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the application should still belong to the scope of protection of the technical solutions of the application.

Claims

1. A solar-powered interfacial evaporator for simultaneous desalination and degradation of organic matter, characterized in that, The solar interface evaporator includes a water-carrying medium loaded with a catalyst, a heat insulation plate, and a photothermal interface; the water-carrying medium loaded with the catalyst passes through the heat insulation plate and contacts the photothermal interface, the photothermal interface is placed above the heat insulation plate, and the lower surface of the photothermal interface contacts the heat insulation plate. The method for preparing the water conveying medium with the supported catalyst includes the following steps: (1) Dissolve FeCl3·6H2O in deionized water, stir well, and add hydrochloric acid to adjust the pH of the mixed solution to 1~5; (2) Place the water delivery medium into the mixed solution obtained in step (1), and use ultrasound to remove air bubbles until the water delivery medium is filled with the mixed solution. Heat the solution at 60-80°C. o Heating at C for 10~36 h allows the generated β-FeOOH to firmly adhere to the water transport medium, resulting in a water transport medium with a supported catalyst. The photothermal interface is a hydrophilic material loaded with photothermal conversion material; The water conveying medium is one or more of cotton core rope, dust-free paper, or cotton cloth.

2. The solar interface evaporator according to claim 1, characterized in that, The FeCl3·6H2O content in the mixed solution of step (1) is 3~27 g / L, the concentration of hydrochloric acid is 0.001~1.2 mol / L, and the ultrasonic time of step (2) is 5~60 min.

3. The solar interface evaporator according to claim 1, characterized in that, The insulation board is made of a material with low thermal conductivity, and its material is one or more of polyethylene foam, polystyrene foam or polypropylene foam.

4. The solar interface evaporator according to claim 1, characterized in that, The hydrophilic material of the photothermal interface is one or more of cotton cloth, hydrogel, cotton strips, or melamine sponge.

5. The solar interface evaporator according to claim 1, characterized in that, The photothermal conversion material loaded on the photothermal interface is one or more of polydopamine, polypyrrole, reduced graphene oxide, or multi-walled carbon nanotubes, and the loading amount of the photothermal conversion material is 1~20%.

6. The method for preparing the solar interface evaporator according to claim 1, comprising the following steps: A hole is made in the middle of the insulation board, and the photothermal interface is placed above the insulation board. The water transport medium loaded with the catalyst passes through the insulation board and comes into contact with the photothermal interface to obtain a solar interface evaporator.

7. The application of the solar interface evaporator according to any one of claims 1 to 5 or the solar interface evaporator prepared by the preparation method according to claim 6 in the treatment of saline organic wastewater.

8. The application according to claim 7, characterized in that, The application method includes the following steps: Under stirring conditions, hydrogen peroxide is added to saline organic wastewater to form a mixed solution. The solar interface evaporator is placed in the mixed solution and suspended above a beaker under the support of a heat insulation plate. The lower end of the water transport medium loaded with the catalyst is immersed in the mixed solution, and the saline organic wastewater is treated by irradiating the photothermal interface with sunlight.

9. The application according to claim 8, characterized in that, The concentration of hydrogen peroxide is 10-200 mM; the salinity of the saline organic wastewater is 0.1-5%; the pH of the mixed solution is 2-8; the organic pollutants are one or more of phenol, aniline, sulfamethoxazole, N,N-dimethylformamide, dyes, or antibiotics; and the duration of sunlight irradiation on the photothermal interface is 3-12 hours.

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