A photocatalytic method for removing antibiotics from wastewater

Abstract

A photocatalytic method for removing antibiotics from wastewater, belonging to the field of wastewater treatment technology, addresses the technical problems of complex photocatalyst recovery processes, poor catalyst stability in water, and low degradation efficiency under visible light during the photocatalytic degradation of antibiotics in wastewater. This invention uses a hydrophobic ionic liquid as the organic component, forming a hybrid material (photocatalyst) through ionic bonds with inorganic components such as organometallic frameworks and polyoxometalates. This material can extract antibiotics from wastewater, and through the synergistic effect of the organometallic framework, polyoxometalates, and ionic liquid, photodegradation of antibiotics is achieved under visible light. The photocatalyst exists in a water-insoluble liquid state, thus allowing for sedimentation and stratification; the lower layer can be collected for recovery and reuse. This invention achieves effective degradation of antibiotics under visible light and features a simple preparation process, reusable catalyst, and no secondary pollution of water bodies by the reaction system.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a photocatalytic method for removing antibiotics from wastewater. Background Technology

[0002] Antibiotics are widely used in the treatment of human diseases and in livestock farming. However, due to their difficulty in degradation, high potential biotoxicity, and severe impact on the ecological environment, antibiotics have become one of the most important pollutants in wastewater that urgently need to be removed. Currently, methods for removing antibiotics from water mainly include physical adsorption, oxidative degradation, biodegradation, membrane separation, and catalytic degradation. However, all of these methods suffer from varying degrees of problems such as low degradation efficiency, complex treatment processes, high material costs, difficulty in catalyst recovery, and a high risk of secondary pollution. Therefore, developing antibiotic degradation methods that are highly efficient, easy to implement, and allow for easy catalyst recovery has become a current research hotspot in water pollutant treatment.

[0003] Photocatalysis is a pollutant treatment method that converts light energy into chemical energy through photocatalysts, using hydroxyl radicals, superoxide radicals, singlet oxygen, and other reactive species to oxidize and decompose pollutants. Currently, there are reports on the use of inorganic compounds such as TiO2, ZnO, ZnS, CdS, and BiOCl, metal-organic framework materials, and composite materials doped with graphene and C3N4 for the photocatalytic degradation of antibiotics in water. However, these photocatalyst materials are generally micro- or nano-scale, which makes catalyst recovery difficult, and residual catalysts can cause secondary pollution of water bodies. Furthermore, these photocatalysts lack stability in water and are prone to physical structural damage, leading to poor performance in multiple cycles. Summary of the Invention

[0004] The main objective of this invention is to overcome the shortcomings of the prior art and solve the technical problems of complex photocatalyst recovery process, poor catalyst stability in water, and low degradation efficiency under visible light in the photocatalytic degradation of antibiotics in wastewater. This invention provides a photocatalytic method for removing antibiotics from wastewater.

[0005] This invention is achieved through the following technical solution: a photocatalytic method for removing antibiotics from wastewater, comprising the following steps:

[0006] S1. Preparation of photocatalysts:

[0007] S1-1. Mix 0.1-10 parts of organometallic framework, 0.1-5 parts of polyoxometalate and 85-99.8 parts of ionic liquid in a uniform weight ratio to obtain a mixture;

[0008] S1-2. Heat the mixture prepared in step S1-1 to 100℃~180℃ and react for 6 hours~12 hours to obtain the photocatalyst;

[0009] S2, photocatalytic reaction of photocatalyst:

[0010] The photocatalyst prepared in step S1 is uniformly mixed with antibiotic-containing wastewater and continuously stirred while being irradiated with visible light. After the photocatalytic reaction is completed for 2-4 hours, the mixture is allowed to stand and separate into layers. The upper layer is water after complete degradation of antibiotics, and the lower layer is the photocatalyst. The mixture is then recycled and reused.

[0011] Further, in step S1-1, the organometallic framework is any one of zirconium terephthalate, 2-aminozirconium terephthalate, or zirconium pyromelliticate.

[0012] Further, in step S1-1, the polyoxometalate is a monovacancy Keggin-type polyoxometalate solution, and its anionic portion is [MW 11 O 39 ], where M is any one of boron, phosphorus or silicon.

[0013] Further, in step S1-1, the ionic liquid is any one of 1-butyl-3-methylimidazolium hexafluorophosphate solution, 1-hexyl-3-methylimidazolium hexafluorophosphate solution, or 1-octyl-3-methylimidazolium hexafluorophosphate solution.

[0014] Furthermore, in step S2, the antibiotics in the wastewater are macrolide antibiotics, lincomycin antibiotics, or quinolone antibiotics.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention achieves photodegradation of antibiotics under visible light through the synergistic effect of an organometallic framework, polyoxometalates, and ionic liquids. When the photocatalyst is mixed with wastewater, it disperses as droplets under stirring, effectively increasing the contact area between the two phases and enhancing reaction activity. Furthermore, the ionic liquid has an enrichment effect on antibiotics, causing them to transfer from the aqueous phase to the ionic liquid phase. Under the visible light catalysis of the organometallic framework and polyoxometalates, the antibiotics in the ionic liquid phase are oxidized and degraded. Because the hydrophobic ionic liquid forms a complex salt structure based on electrostatic interactions with the organometallic framework and polyoxometalates, it exhibits overall insolubility in water. After the reaction system is allowed to stand, this ionic liquid complex salt system rapidly separates from the aqueous phase due to density differences and settles to the lower layer. The collected lower layer does not require dehydration or drying and can be directly reused for photocatalytic degradation reactions; no significant decrease in photocatalytic performance is observed after five cycles. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the embodiments. Example 1

[0018] A photocatalytic method for removing antibiotics from wastewater includes the following steps:

[0019] S1. Preparation of photocatalysts:

[0020] S1-1, 0.1g of zirconium terephthalate and 5g of [PW] anion 11 O 39 A mixture was prepared by uniformly mixing a single-vacancy Keggin-type polyoxometalate solution and 94.9 g of 1-butyl-3-methylimidazolium hexafluorophosphate solution.

[0021] S1-2. Heat the mixture prepared in step S1-1 to 120°C and react for 12 hours to obtain the photocatalyst;

[0022] S2, photocatalytic reaction of photocatalyst:

[0023] The photocatalyst prepared in step S1 was mixed with wastewater containing 10 mg / L erythromycin at a volume ratio of 1:5. A 300W xenon lamp with a 420 nm filter was used as a visible light source. The mixture was continuously stirred while being irradiated with visible light. After 4 hours of photocatalytic reaction, the mixture was allowed to stand and separate into layers. The upper layer of liquid was tested and found to be completely degraded antibiotics. The lower layer of liquid was the photocatalyst, which was recovered and reused. Example 2

[0024] A photocatalytic method for removing antibiotics from wastewater includes the following steps:

[0025] S1. Preparation of photocatalysts:

[0026] S1-1, 10g of zirconium terephthalate and 0.1g of anion [SiW 11 O 39 A mixture was prepared by uniformly mixing a single-vacancy Keggin-type polyoxometalate solution and 89.9 g of 1-hexyl-3-methylimidazolium hexafluorophosphate solution.

[0027] S1-2. Heat the mixture prepared in step S1-1 to 180°C and react for 6 hours to obtain the photocatalyst;

[0028] S2, photocatalytic reaction of photocatalyst:

[0029] The photocatalyst prepared in step S1 was mixed with wastewater containing 10 mg / L azithromycin at a volume ratio of 1:5. A 300W xenon lamp with a 420 nm filter was used as a visible light source. The mixture was continuously stirred while being irradiated with visible light. After 4 hours of photocatalytic reaction, the mixture was allowed to stand and separate into layers. The upper layer of liquid was tested and found to be completely degraded antibiotics. The lower layer of liquid was the photocatalyst, which was recovered and reused. Example 3

[0030] A photocatalytic method for removing antibiotics from wastewater includes the following steps:

[0031] S1. Preparation of photocatalysts:

[0032] S1-1, 5g of 2-aminoterephthalate zirconium, 5g of anionic [BW] 11 O 39 A mixture was prepared by uniformly mixing a single-vacancy Keggin-type polyoxometalate solution and 90 g of 1-octyl-3-methylimidazolium hexafluorophosphate solution.

[0033] S1-2. Heat the mixture prepared in step S1-1 to 100°C and react for 12 hours to obtain the photocatalyst;

[0034] S2, photocatalytic reaction of photocatalyst:

[0035] The photocatalyst prepared in step S1 was mixed with wastewater containing 10 mg / L lincomycin at a volume ratio of 1:5. A 300W xenon lamp with a 420 nm filter was used as a visible light source. The mixture was continuously stirred while being irradiated with visible light. After 2 hours of photocatalytic reaction, the mixture was allowed to stand and separate into layers. The upper layer of liquid was tested and found to be completely degraded antibiotics. The lower layer of liquid was the photocatalyst, which was recovered and reused. Example 4

[0036] A photocatalytic method for removing antibiotics from wastewater includes the following steps:

[0037] S1. Preparation of photocatalysts:

[0038] S1-1, 2g of zirconium pyromelliticate and 2g of anion [PW] 11 O 39 A mixture was prepared by uniformly mixing a single-vacancy Keggin-type polyoxometalate solution and 96 g of 1-butyl-3-methylimidazolium hexafluorophosphate solution.

[0039] S1-2. Heat the mixture prepared in step S1-1 to 160°C and react for 10 hours to obtain the photocatalyst.

[0040] S2, photocatalytic reaction of photocatalyst:

[0041] The photocatalyst prepared in step S1 was mixed with wastewater containing 10 mg / L levofloxacin at a volume ratio of 1:5. A 300W xenon lamp with a 420 nm filter was used as a visible light source. The mixture was continuously stirred while being irradiated with visible light. After 3 hours of photocatalytic reaction, the mixture was allowed to stand and separate into layers. The upper layer of liquid was tested and found to be completely degraded antibiotics. The lower layer of liquid was the photocatalyst, which was recovered and reused. Example 5

[0042] A photocatalytic method for removing antibiotics from wastewater includes the following steps:

[0043] S1. Preparation of photocatalysts:

[0044] S1-1, 10g of zirconium terephthalate and 5g of anion exchanger [SiW] 11 O 39 A mixture was prepared by uniformly mixing a single-vacancy Keggin-type polyoxometalate solution and 85 g of 1-octyl-3-methylimidazolium hexafluorophosphate solution.

[0045] S1-2. Heat the mixture prepared in step S1-1 to 100°C and react for 12 hours to obtain the photocatalyst;

[0046] S2, photocatalytic reaction of photocatalyst:

[0047] The photocatalyst prepared in step S1 was mixed with wastewater containing 10 mg / L ciprofloxacin at a volume ratio of 1:5. A 300W xenon lamp with a 420 nm filter was used as a visible light source. The mixture was continuously stirred while being irradiated with visible light. After 3 hours of photocatalytic reaction, the mixture was allowed to stand and separate into layers. The upper layer of liquid was tested and found to be completely degraded antibiotics. The lower layer of liquid was the photocatalyst, which was recovered and reused. Example 6

[0048] A photocatalytic method for removing antibiotics from wastewater includes the following steps:

[0049] S1. Preparation of photocatalysts:

[0050] S1-1, 0.1g of zirconium terephthalate and 0.1g of [PW] anion... 11 O 39 A mixture was prepared by uniformly mixing a single-vacancy Keggin-type polyoxometalate solution and 99.8 g of 1-hexyl-3-methylimidazolium hexafluorophosphate solution.

[0051] S1-2. Heat the mixture prepared in step S1-1 to 120°C and react for 6 hours to obtain the photocatalyst;

[0052] S2, photocatalytic reaction of photocatalyst:

[0053] The photocatalyst prepared in step S1 was mixed with wastewater containing 10 mg / L erythromycin at a volume ratio of 1:5. A 300W xenon lamp with a 420 nm filter was used as a visible light source. The mixture was continuously stirred while being irradiated with visible light. After 4 hours of photocatalytic reaction, the mixture was allowed to stand and separate into layers. The upper layer of liquid was tested and found to be completely degraded antibiotics. The lower layer of liquid was the photocatalyst, which was recovered and reused.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A photocatalytic method for removing antibiotics from wastewater, characterized in that, Includes the following steps: S1. Preparation of photocatalysts: S1-1. A mixture is prepared by uniformly mixing 0.1-10 parts of an organometallic framework, 0.1-5 parts of a polyoxometalate, and 85-99.8 parts of an ionic liquid according to a weight ratio; the organometallic framework is any one of zirconium terephthalate, 2-aminozirconium terephthalate, or zirconium pyromelliticate; the polyoxometalate is a monovacancy Keggin-type polyoxometalate solution, the anionic portion of which is [MW... 11 O 39 ], wherein M is any one of boron, phosphorus or silicon; the ionic liquid is any one of 1-butyl-3-methylimidazolium hexafluorophosphate solution, 1-hexyl-3-methylimidazolium hexafluorophosphate solution or 1-octyl-3-methylimidazolium hexafluorophosphate solution; S1-2. Heat the mixture prepared in step S1-1 to 100℃~180℃ and react for 6 hours~12 hours to obtain the photocatalyst; S2, photocatalytic reaction of photocatalyst: The photocatalyst prepared in step S1 is uniformly mixed with antibiotic-containing wastewater and continuously stirred while being irradiated with visible light. After the photocatalytic reaction is completed for 2-4 hours, the mixture is allowed to stand and separate into layers. The upper layer is water after complete degradation of antibiotics, and the lower layer is the photocatalyst. The mixture is then recycled and reused.

2. The photocatalytic method for removing antibiotics from wastewater according to claim 1, characterized in that: In step S2, the antibiotics in the wastewater are macrolide antibiotics, lincomycin antibiotics, or quinolone antibiotics.