Preparation method of hydrophilic-hydrophobic boron nitride and application of hydrophilic-hydrophobic boron nitride in wastewater remediation

Abstract

The invention relates to a hydrophilic-hydrophobic adjustable boron nitride material and application thereof in wastewater remediation, and belongs to the technical field of functional materials and efficient water pollution treatment. The preparation method comprises the following steps: uniformly dispersing a nitrogen source and a boron source in a solvent, and performing constant-temperature evaporation in an oil bath until complete drying to obtain a boron nitride precursor; then, grinding, putting into a tubular furnace, calcining under the protection of inert gas, and annealing to obtain a hydrophobic boron nitride product; carrying out hollow combustion and oxygen doping on the hydrophobic boron nitride in a muffle furnace to obtain a hydrophilic modified boron nitride material; the method has the advantages that the specific surface area is high, the chemical stability is high, the method can be used for selectively adsorbing and enriching water pollutants with different hydrophilic and hydrophobic parameters, and the method provides a new idea for selectively removing organic pollutants in water.

Description

Technical Field

[0001] The present invention belongs to the technical fields of functional materials and efficient water pollution treatment, and particularly relates to boron nitride materials and their applications in wastewater remediation, and more particularly to the regulated preparation of hydrophilic and hydrophobic boron nitride materials and their applications in the selective removal of pollutants in water bodies. Background Art

[0002] In recent years, water is a fundamental and strategic resource for human survival, and water environmental pollution poses a serious threat to human health, especially organic pollutants with complex compositions, high toxicity, and difficult degradation. Therefore, it is necessary to develop new functional materials to deal with organic pollutants in wastewater.

[0003] Currently, the methods for removing organic pollutants in wastewater mainly include physical treatment methods (such as flocculation, membrane filtration, and adsorption), chemical treatment methods (photooxidation, electrochemical oxidation, and ozone oxidation), biological treatment methods (such as traditional activated sludge method and microbial reactor), etc. Among them, the adsorption method refers to the process in which one or more components in a fluid accumulate on the surface of a porous solid material when the fluid comes into contact with it. This method is simple to operate, requires low equipment requirements, and has high industrial application feasibility. Its basic principle is that when a liquid or gas mixture is in full contact with the adsorbent for a long time, the system reaches equilibrium, and the equilibrium adsorption capacity of the adsorbate depends first on the chemical composition and physical structure of the adsorbent, and at the same time on the temperature and pressure of the system and the concentration or partial pressure of this component and other components. However, the currently common water body adsorbents mainly have the disadvantages of low adsorption capacity, poor adsorption selectivity, and instability of the adsorbent. A large amount of adsorbent needs to be used in industrial wastewater treatment, and the cost is expensive, which limits its development. Considering that the adsorption and removal of organic pollutants depend on the substrate concentration near the catalyst surface, it means that the target pollutants can be enriched on the surface to improve the removal rate, and the hydrophilicity and hydrophobicity of the pollutants and the adsorbent are the key factors for the surface enrichment of the target pollutants. Catalysts with high hydrophobicity are more likely to adsorb pollutants with high hydrophobicity, and vice versa. Therefore, developing an adsorbent material with controllable hydrophilicity and hydrophobicity to achieve high-selectivity removal of water body pollutants has application value.

[0004] Boron nitride (BN) is composed of B and N elements, and the elements are connected by strong covalent bonds, having excellent chemical stability and hydrophobicity. In recent years, the modification of BN and its composites for the adsorption and removal of water body pollutants has gradually attracted the attention of domestic and foreign scientific researchers. For example, Peng et al. synthesized diacylamidopyridine (DABP)-modified hierarchical porous carbon-doped boron nitride (BCN), and provided more adsorption sites by introducing bifunctional groups such as bipyridine. The adsorption kinetics and adsorption capacity of the material were significantly improved ( Science of The Total Environment 2023, 866, 161378). In addition, Wang et al. prepared hierarchical porous boron nitride nanosheets (hp-BNNSs) by pyrolyzing a mixture of boric acid and urea at 1000 °C for 5 h, which have a wide range of comprehensive adsorption capacities for water pollutants such as dyes, heavy metals, and antibiotics, and the material can be recycled multiple times during use ( Colloids and Surfaces A: Physicochemical and Engineering Aspects 2020, 598 , 124865). Although certain progress has been made in boron nitride adsorption materials, existing methods mainly focus on improving the performance of adsorbents, and there is less research on the modification of adsorption materials and selective removal of pollutants, especially the hydrophilic-hydrophobic modification of boron nitride materials and the internal relationship between their selective removal of pollutants. SUMMARY OF THE INVENTION

[0005] The present invention addresses the above problems and provides a boron nitride material with adjustable hydrophilic-hydrophobic properties and its application in wastewater remediation. The boron nitride material with adjustable hydrophilic-hydrophobic properties changes its hydrophilic-hydrophobic properties by regulating the oxygen content in boron nitride, and it exhibits excellent selectivity in the adsorption and removal of pollutants. The hydrophilic-hydrophobic adjustable boron nitride adsorption material provided in the present invention provides a new idea for the efficient treatment of organic wastewater and has broad application prospects.

[0006] A boron nitride material with adjustable hydrophilic-hydrophobic properties and its application in wastewater remediation include the following steps: (1) Preparation of hydrophobic boron nitride: A nitrogen source and a boron source are uniformly dispersed in a solvent and stirred and dried according to a certain mass ratio to obtain a boron nitride precursor. After grinding, it is calcined in a tubular furnace under an inert gas condition to obtain a hydrophobic boron nitride product; (2) Hydrophilic modification of boron nitride: The obtained boron nitride precursor powder is calcined in a muffle furnace, and the doping amount of oxygen in boron nitride is regulated by changing the calcination time and temperature to obtain a boron nitride product with adjustable hydrophilic-hydrophobic properties; (3) Method for selectively removing organic pollutants in water: The boron nitride product with a hydrophilic-hydrophobic gradient prepared in step (1) or (2) is placed in an organic pollutant solution with different hydrophobicity coefficients for adsorption, and its adsorption law and performance are detected.

[0007] Preferably, the boron source in step (1) is one or more of boric acid, boron oxide, borax, ammonium tetrafluoroborate, borane ammonia, and sodium borohydride, the nitrogen source is one or more of melamine, urea, cyanuric acid, sodium azide, dicyandiamide, and sodium amide, and the mass ratio of the boron source to the nitrogen source is 1:0.1 - 10.

[0008] Preferably, the solvent described in step (1) is one or more of water, acetonitrile, ethanol, methanol, tert-butanol, isopropanol, dimethyl sulfoxide, styrene, perchloroethylene, trichloroethylene, ethylene glycol ether, and triethanolamine.

[0009] Preferably, a magnetic stir bar should be placed in the nitrogen source and boron source mixture described in step (1), and heated and stirred evenly in a magnetic heater until completely dry.

[0010] Preferably, the heating temperature described in step (1) is 50~120 °C, and the heating conditions are one or more of oil bath heating, water bath heating, sand bath heating, electromagnetic wave heating, microwave heating, and ultraviolet light heating.

[0011] Preferably, the inert gas described in step (1) is one of nitrogen, argon, or ammonia to prevent high-temperature oxidation or denaturation.

[0012] Preferably, the heating rate of the tube furnace in step (1) is 1~10 °C / min, the calcination temperature is 800~1300 °C, and the holding time is 2~12 h. The hydrophobic properties of boron nitride obtained under different conditions are different.

[0013] Preferably, the time for dry firing in the muffle furnace in step (2) is 1~10 h, and the dry firing temperature is controlled at 350~850 °C. The hydrophilic and hydrophobic properties of boron nitride are regulated by the length of the dry firing time and the height of the dry firing temperature.

[0014] Preferably, the ratio of the mass (mg) of boron nitride to the volume (mL) of the organic pollutant solution in step (3) is 1:10~100.

[0015] Preferably, the organic pollutant described in step (3) can be one or more of sulfamethoxazole, phenol, mixed cresols, p-chlorophenol, carbamazepine, 2,4,6-trimethylphenol, 4-chloro-3,5-dimethylphenol, bisphenol A, 5-chloro-2-(2,4-dichlorophenoxy)phenol, and the adsorption time is 5-45 min.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) The process for regulating the hydrophilic and hydrophobic properties of boron nitride is simple, and the effective regulation of hydrophilic and hydrophobic properties can be achieved without a complex graft modification process.

[0017] (2) Boron nitride materials have obvious advantages in terms of stability, corrosion resistance, adsorption capacity, etc. compared with commercial activated carbon adsorbents. Modified boron nitride can achieve selective adsorption of pollutants, improving the problem of low efficiency in selectively removing pollutants by existing adsorption materials. The hydrophilic-hydrophobic adjustable boron nitride has a high specific surface area, high chemical stability, and strong selective adsorption ability for water pollutants. The method for regulating hydrophilic-hydrophobicity is simple and the intrinsic structure of the material is well retained. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a contact angle test diagram of hydrophilic modified boron nitride in Example 3 of the present invention DETAILED DESCRIPTION OF THE INVENTION The present invention will be further described below in conjunction with specific examples. These implementation cases are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0020] Example 1: (1) Disperse 1.23 g of boric acid and 1.26 g of melamine in 100 mL of water, then place them in a glass beaker with a specification of 500 mL, add a magnetic stirrer, and evaporate and stir at 85 °C in an oil bath for 10 h until the solvent is completely evaporated to obtain a powdery sample A of boron nitride precursor.

[0021] (2) Grind the powdery sample A obtained in step (1) and place it in a tubular furnace. Heat it to 1200 °C under argon protection and keep it warm for 2 h to obtain hydrophobic boron nitride.

[0022] (3) Take 3 mg of hydrophobic boron nitride powder and place it in 20 mL of phenol, p-chlorophenol, and bisphenol A solutions with a concentration of 100 μM / L respectively. Adsorb for 30 min, and take the solutions at two time points of 0 min and 30 min for liquid chromatography analysis.

[0023] The adsorption performance of hydrophobic boron nitride synthesized in this example: For phenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 1.39, and the removal rate of pollutants after 30 min of adsorption is 17.04%; for p-chlorophenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 2.4, and the removal rate of pollutants after 30 min of adsorption is 49.87%; for bisphenol A (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 3.43, and the removal rate of pollutants after 30 min of adsorption is 85.24%. The above results show that hydrophobic boron nitride is more likely to adsorb pollutants with a high hydrophobic coefficient value.

[0024] Example 2: (1) Disperse 1.23 g of boric acid and 1.26 g of melamine in 100 mL of water, then place them in a 500 mL glass beaker, add a magnetic stir bar, and evaporate and stir at 85 °C in an oil bath for 10 h until the solvent is completely evaporated to dryness, obtaining a powdery sample A of boron nitride precursor.

[0025] (2) Grind the powdery sample A obtained in step (1) and place it in a tubular furnace. Heat it to 1000 °C under argon protection and hold for 2 h to obtain hydrophobic boron nitride.

[0026] (3) Take 3 mg of the hydrophobic boron nitride powder and place it in 20 mL of phenol, p-chlorophenol, and bisphenol A solutions with a concentration of 100 μM / L respectively. Adsorb for 30 min, and take the solutions at two time points of 0 min and 30 min for liquid chromatography analysis.

[0027] The adsorption performance of the hydrophobic boron nitride synthesized in this example: for phenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 1.39, and the removal rate of the pollutant after 30 min of adsorption is 23.01%; for p-chlorophenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 2.4, and the removal rate of the pollutant after 30 min of adsorption is 46.29%; for bisphenol A (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 3.43, and the removal rate of the pollutant after 30 min of adsorption is 76.52%. The above results show that the decrease in the preparation temperature of hydrophobic boron nitride leads to a decrease in the removal effect of pollutants with high hydrophobic coefficient values.

[0028] Example 3: (1) Disperse 1.23 g of boric acid and 1.26 g of melamine in 100 mL of water, then place them in a 500 mL glass beaker, add a magnetic stir bar, and evaporate and stir at 85 °C in an oil bath for 10 h until the solvent is completely evaporated to dryness, obtaining a powdery sample A of boron nitride precursor.

[0029] (2) Grind the powdery sample A obtained in step (1) and place it in a tubular furnace. Heat it to 1200 °C under argon protection and hold for 2 h to obtain hydrophobic boron nitride. Subsequently, place the hydrophobic boron nitride in a muffle furnace and calcine it at 600 °C for 2 h to obtain boron nitride with regulated hydrophilicity and hydrophobicity.

[0030] (3) Take 3 mg of the hydrophobic boron nitride powder and place it in 20 mL of phenol, p-chlorophenol, and bisphenol A solutions with a concentration of 100 μM / L respectively. Adsorb for 30 min, and take the solutions at two time points of 0 min and 30 min for liquid chromatography analysis.

[0031] Adsorption performance of the synthesized hydrophobic boron nitride in this example: For phenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 1.39, and the removal rate of the pollutant after 30 minutes of adsorption is 45.28%; for 4-chlorophenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 2.4, and the removal rate of the pollutant after 30 minutes of adsorption is 48.39%; for bisphenol A (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 3.43, and the removal rate of the pollutant after 30 minutes of adsorption is 52.48%. The above results indicate that after hydrophilic modification, the adsorption and removal rate of boron nitride for pollutants with a high hydrophobic coefficient value decreases, while the adsorption and removal rate for pollutants with a low hydrophobic coefficient value increases.

[0032] Example 4: (1) Disperse 1.23 g of boric acid and 1.26 g of melamine in 100 mL of water, then place them in a 500 mL glass beaker, add a magnetic stir bar, and evaporate and stir at 85 °C in an oil bath for 10 h until the solvent is completely evaporated to obtain a powdery sample A of boron nitride precursor.

[0033] (2) Grind the powdery sample A obtained in step (1) and place it in a tube furnace. Heat it to 1200 °C under argon protection and keep it at this temperature for 2 h to obtain hydrophobic boron nitride. Subsequently, place the hydrophobic boron nitride in a muffle furnace and calcine it at 600 °C for 4 h to obtain boron nitride with regulated hydrophilicity and hydrophobicity.

[0034] (3) Take 3 mg of hydrophobic boron nitride powder and place it in 20 mL of solutions of phenol, 4-chlorophenol, and bisphenol A with a concentration of 100 μM / L respectively. Adsorb for 30 min, and take the solutions at two time points of 0 min and 30 min for liquid chromatography analysis.

[0035] Adsorption performance of the synthesized hydrophobic boron nitride in this example: For phenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 1.39, and the removal rate of the pollutant after 30 minutes of adsorption is 55.31%; for 4-chlorophenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 2.4, and the removal rate of the pollutant after 30 minutes of adsorption is 49.33%; for bisphenol A (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 3.43, and the removal rate of the pollutant after 30 minutes of adsorption is 42.68%. The above results indicate that during the hydrophilic modification process, the increase in the holding time will improve the hydrophilicity of boron nitride, which is more conducive to the removal of pollutants with a low hydrophobic coefficient value.

[0036] Example 5: (1) Disperse 1.23 g of boric acid and 1.26 g of melamine in 100 mL of water, then place them in a 500 mL glass beaker, add a magnetic stir bar, and evaporate and stir for 10 h under an 85 °C oil bath condition until the solvent is completely evaporated to dryness, obtaining a powdery sample A of boron nitride precursor.

[0037] (2) Grind the powdery sample A obtained in step (1) and place it in a tubular furnace. Heat it to 1200 °C under argon protection and hold for 2 h to obtain hydrophobic boron nitride. Subsequently, place the hydrophobic boron nitride in a muffle furnace and calcine it at 850 °C for 2 h to obtain boron nitride with hydrophilic-hydrophobic regulation.

[0038] (3) Respectively take 3 mg of hydrophobic boron nitride powder and place it in 20 mL of phenol, p-chlorophenol, and bisphenol A solutions with a concentration of 100 μM / L. Adsorb for 30 min, and take the solutions at two time points of 0 min and 30 min for liquid chromatography analysis.

[0039] The adsorption performance of the hydrophobic boron nitride synthesized in this example: For phenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 1.39, and the removal rate of the pollutant after 30 min of adsorption is 53.89%; for p-chlorophenol (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 2.4, and the removal rate of the pollutant after 30 min of adsorption is 50.31%; for bisphenol A (20 mL, 100 μM / L), the hydrophobic parameter value (XlogP) is 3.43, and the removal rate of the pollutant after 30 min of adsorption is 49.66%. The above results show that the increase in the calcination temperature during the hydrophilic modification process will improve the hydrophilicity of boron nitride, which is more conducive to the removal of pollutants with low hydrophobic coefficient values.

[0040] Example 6: (1) Disperse 1.23 g of boric acid and 1.26 g of melamine in 100 mL of water, then place them in a 500 mL glass beaker, add a magnetic stir bar, and evaporate and stir for 10 h under an 85 °C oil bath condition until the solvent is completely evaporated to dryness, obtaining a powdery sample A of boron nitride precursor.

[0041] (2) Grind the powdery sample A obtained in step (1) and place it in a tubular furnace. Heat it to 1200 °C under argon protection and hold for 2 h to obtain hydrophobic boron nitride. Subsequently, place the hydrophobic boron nitride in a muffle furnace and calcine it at 850 °C for 4 h to obtain boron nitride with hydrophilic-hydrophobic regulation.

[0042] (3)Weigh 3 mg of hydrophobic boron nitride powder respectively and place them in 20 mL of phenol, p-chlorophenol, and bisphenol A solutions with a concentration of 100 μM / L. Adsorb for 30 min, and take the solutions at two time points of 0 min and 30 min for liquid chromatography analysis.

[0043] The adsorption performance of the hydrophobic boron nitride synthesized in this example: The hydrophobic parameter value (XlogP) of phenol (20 mL 100 μM / L) is 1.39, and the removal rate of the pollutant after 30 min of adsorption is 47.08%; the hydrophobic parameter value (XlogP) of p-chlorophenol (20 mL 100 μM / L) is 2.4, and the removal rate of the pollutant after 30 min of adsorption is 49.18%; the hydrophobic parameter value (XlogP) of bisphenol A (20 mL 100 μM / L) is 3.43, and the removal rate of the pollutant after 30 min of adsorption is 50.19%. The above results show that the increase in the air-burning temperature during the hydrophilic modification process will improve the hydrophilicity of boron nitride, which is beneficial to the removal of pollutants with low hydrophobic coefficient values. However, when the temperature is too high, the effect of improving the selective removal of pollutants by hydrophilic modification will decline.

[0044] Example 7: (1)Disperse 1.23 g of boric acid and 1.26 g of melamine in 100 mL of water, then place them in a glass beaker with a specification of 500 mL, put in a magnetic stirrer, and evaporate and stir for 10 h under the condition of an 85 °C oil bath until the solvent is completely evaporated to obtain a powdery sample A of boron nitride precursor.

[0045] (2)Grind the powdery sample A obtained in step (1) and place it in a tubular furnace. Heat it to 1200 °C under the protection of argon and keep it at this temperature for 2 h to obtain hydrophobic boron nitride. Subsequently, place the hydrophobic boron nitride in a muffle furnace and conduct air-burning at 350 °C for 4 h to obtain boron nitride with regulated hydrophilicity and hydrophobicity.

[0046] (3)Weigh 3 mg of hydrophobic boron nitride powder respectively and place them in 20 mL of phenol, p-chlorophenol, and bisphenol A solutions with a concentration of 100 μM / L. Adsorb for 30 min, and take the solutions at two time points of 0 min and 30 min for liquid chromatography analysis.

[0047] Adsorption performance of the synthesized hydrophobic boron nitride in this example: The hydrophobic parameter value (XlogP) of phenol (20 mL, 100 μM / L) is 1.39, and the removal rate of pollutants after 30 minutes of adsorption is 32.38%; the hydrophobic parameter value (XlogP) of p-chlorophenol (20 mL, 100 μM / L) is 2.4, and the removal rate of pollutants after 30 minutes of adsorption is 47.68%; the hydrophobic parameter value (XlogP) of bisphenol A (20 mL, 100 μM / L) is 3.43, and the removal rate of pollutants after 30 minutes of adsorption is 77.15%. The above results indicate that the decrease in the annealing temperature during the hydrophilic modification process can improve the hydrophilicity of boron nitride to a certain extent, which is beneficial to enhancing the removal of pollutants with low hydrophobic coefficient values.

[0048] Example 8: (1) Disperse 1.23 g of boric acid and 1.26 g of melamine in 100 mL of water, then place them in a 500 mL glass beaker, add a magnetic stir bar, and evaporate and stir at 85 °C in an oil bath for 10 h until the solvent is completely evaporated to obtain a powdery sample A of boron nitride precursor.

[0049] (2) Grind the powdery sample A obtained in step (1) and place it in a tube furnace. Heat it to 1200 °C under argon protection and hold for 2 h to obtain hydrophobic boron nitride. Subsequently, place the hydrophobic boron nitride in a muffle furnace and anneal it at 500 °C for 6 h to obtain hydrophilic-hydrophobic regulated boron nitride.

[0050] (3) Take 3 mg of hydrophobic boron nitride powder and place it in 20 mL of solutions of phenol, p-chlorophenol, and bisphenol A with a concentration of 100 μM / L respectively. Adsorb for 30 min, and take the solutions at two time points of 0 min and 30 min for liquid chromatography analysis.

[0051] Adsorption performance of the synthesized hydrophobic boron nitride in this example: The hydrophobic parameter value (XlogP) of phenol (20 mL, 100 μM / L) is 1.39, and the removal rate of pollutants after 30 minutes of adsorption is 71.23%; the hydrophobic parameter value (XlogP) of p-chlorophenol (20 mL, 100 μM / L) is 2.4, and the removal rate of pollutants after 30 minutes of adsorption is 51.18%; the hydrophobic parameter value (XlogP) of bisphenol A (20 mL, 100 μM / L) is 3.43, and the removal rate of pollutants after 30 minutes of adsorption is 37.55%. The above results indicate that appropriate annealing temperature and holding time during the hydrophilic modification process are more conducive to adjusting the effect of boron nitride on selectively removing pollutants.

[0052] Comparative Example 1: (1)Weigh 3 mg of commercial activated carbon respectively and place them in 20 mL of phenol, p-chlorophenol, and bisphenol A solutions with a concentration of 100 μM / L. Adsorb for 30 min, and take the solutions at the two time points of 0 min and 30 min for liquid chromatography analysis.

[0053] The adsorption performance of activated carbon in this example: For phenol (20 mL 100 μM / L), the hydrophobic parameter value (XlogP) is 1.39, and the removal rate of the pollutant after 30 min of adsorption is 23.15%; for p-chlorophenol (20 mL 100 μM / L), the hydrophobic parameter value (XlogP) is 2.4, and the removal rate of the pollutant after 30 min of adsorption is 26.51%; for bisphenol A (20 mL 100 μM / L), the hydrophobic parameter value (XlogP) is 3.43, and the removal rate of the pollutant after 30 min of adsorption is 17.21%. The above results show that the selective removal of pollutants with different hydrophobic parameter values by activated carbon has no obvious regularity, and the adsorption effect is not good.

[0054] Comparative Example 2: (1)Weigh 3 mg of commercial graphitic carbon nitride (g-C3N4) powder respectively and place them in 20 mL of phenol, p-chlorophenol, and bisphenol A solutions with a concentration of 100 μM / L. Adsorb for 30 min, and take the solutions at the two time points of 0 min and 30 min for liquid chromatography analysis.

[0055] The adsorption performance of graphitic carbon nitride (g-C3N4) in this example: For phenol (20 mL 100 μM / L), the hydrophobic parameter value (XlogP) is 1.39, and the removal rate of the pollutant after 30 min of adsorption is 16.27%; for p-chlorophenol (20 mL 100 μM / L), the hydrophobic parameter value (XlogP) is 2.4, and the removal rate of the pollutant after 30 min of adsorption is 12.65%; for bisphenol A (20 mL 100 μM / L), the hydrophobic parameter value (XlogP) is 3.43, and the removal rate of the pollutant after 30 min of adsorption is 14.71%. The above results show that the selective removal of pollutants with different hydrophobic parameter values by graphitic carbon nitride (g-C3N4) has no obvious regularity, and the adsorption effect is not good.

[0056] Summary of performance evaluation: According to the above examples and comparative examples, the performance is summarized as shown in the following table: The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field according to the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art shall fall within the protection scope determined by the claims.

Claims

1. A preparation method of hydrophilic and hydrophobic boron nitride, characterized in that It includes the following steps: (1) Preparation of hydrophobic boron nitride: A nitrogen source and a boron source are uniformly dispersed in a solvent, placed in an oil bath and evaporated at a constant temperature until completely dry to obtain a boron nitride precursor; subsequently, it is ground and placed in a tube furnace for calcination under the protection of an inert gas, and annealed to obtain a hydrophobic boron nitride product; (2) Hydrophilic modification of boron nitride: The hydrophobic boron nitride in step (1) is calcined in a muffle furnace with oxygen doping to obtain a hydrophilic modified boron nitride material; the calcination temperature is 350-850 °C, and the calcination time is 1-10 h.

2. The preparation method of the hydrophilic and hydrophobic boron nitride according to claim 1, characterized in that, The boron source described in step (1) is one or more of boric acid, boron oxide, borax, ammonium tetrafluoroborate, borane ammonia, and sodium borohydride; the nitrogen source is one or more of melamine, urea, cyanuric acid, sodium azide, dicyandiamide, and sodium amide, and the mass ratio of the boron source to the nitrogen source is 1:0.1-10.

3. The preparation method of a hydrophobic and hydrophilic boron nitride according to claim 1, characterized in that, The solvent described in step (1) is one or more of water, acetonitrile, ethanol, methanol, tert-butanol, isopropanol, dimethyl sulfoxide, styrene, perchloroethylene, trichloroethylene, ethylene glycol ether, or triethanolamine.

4. The preparation method of the hydrophilic and hydrophobic boron nitride according to claim 1, wherein, The evaporation drying temperature in step (1) is 50-120 °C, the annealing treatment temperature is 800-1300 °C, the annealing time is 2-12 h, and the inert gas is one of nitrogen or argon.

5. Application of a hydrophilic and hydrophobic boron nitride prepared according to claims 1-4 in wastewater remediation, characterized in that: A hydrophilic and hydrophobic boron nitride material is placed in an organic pollutant solution with different hydrophobicity coefficients for adsorption, and the pollutants are one or more of sulfamethoxazole, phenol, mixed cresols, p-chlorophenol, carbamazepine, 2,4,6-trimethylphenol, or bisphenol A.

6. The application of the hydrophilic and hydrophobic boron nitride in wastewater remediation according to claim 5, wherein The mass ratio of the boron nitride to the volume of the organic pollutant solution is 1:10-100.

Images