Application of a microwave-efficiently prepared bio-carbon aerogel catalyst in the degradation of organic pollutants

Abstract

This invention utilizes microwave-assisted pyrolysis to prepare a metal-free biocarbon aerogel catalyst with abundant cross-linked pores, and applies it to the effective catalytic activation of peroxymonosulfate (PMS) and the degradation of organic pollutants. The metal-free biocarbon aerogel catalyst was prepared by uniformly grinding a solid mixture of plant biomass α-cellulose, sodium lignin sulfonate, and KOH, and then heating it in a household microwave oven at 650 W for 5 minutes. KOH, as a chemical activator and microwave absorber, facilitates the formation of a porous structure in the biocarbon aerogel catalyst. Microwave treatment and the introduction of sodium lignin sulfonate promote the formation of C=O groups, thiophene S and C vacancies, and the expansion of specific surface area. Thiophene S and C=O, as the main active sites, promote the... 1 O2 removal via non-radical pathways; simultaneously, C vacancies can further promote pollutant degradation by enhancing substrate adsorption and promoting PMS activation. The bio-carbon aerogel catalyst achieves 99.9% OTC removal within 15 min, with a rate constant as high as 0.818 min. ‑1 .

Description

Technical Field

[0001] This invention relates to the application of a microwave-efficiently prepared bio-carbon aerogel catalyst in the degradation of organic pollutants. Background Technology

[0002] Biomass-derived carbon materials typically possess tunable pore structures, modifiable surface chemistry, and good thermal stability, making them particularly significant for clean energy storage and environmental remediation. Cellulose and lignin, as major components of plant biomass, are attractive precursors for preparing various carbon-based materials due to their abundance, renewability, low cost, and non-toxicity. Compared to traditional pyrolysis, microwave carbonization offers advantages such as non-contact heating, low energy consumption, and selective heating. However, because biomass is not an effective microwave absorber, research on microwave carbonization of biomass has been quite limited to date.

[0003] Pollution has become a major global problem. Studies have shown that residual antibiotics in the environment can lead to the death of microorganisms and the spread of antibiotic resistance genes. In terms of pollutant removal, advanced oxidation processes based on peroxymonosulfate (PMS) activation are considered an effective way to oxidize pollutants into degradable or harmless substances. Biocarbon-based catalysts, due to their large surface area and abundant active functional groups, have been widely used for the removal of toxic pollutants from wastewater. How to construct green, low-cost, and efficient metal-free biocarbon catalysts to activate PMS and achieve efficient degradation of organic pollutants in wastewater has become a hot topic in water pollution control research. Summary of the Invention

[0004] This invention uses plant biomass α-cellulose and sodium lignin sulfonate as raw materials, and KOH as an activator and microwave absorber. All solids are mixed evenly in a mortar, and then subjected to simple microwave-assisted pyrolysis for 5 minutes to prepare a metal-free bio-carbon aerogel catalyst with abundant cross-linked pores. The catalyst preparation method in this invention is simple and quick. The catalyst can effectively activate PMS for the degradation of organic pollutants, and the catalyst is easily recyclable.

[0005] This invention discloses the application of a microwave-efficiently prepared biocarbon aerogel catalyst in the degradation of organic pollutants. Its features include: employing a simple microwave pyrolysis method, using low-cost, non-toxic plant biomass α-cellulose and sodium lignin sulfonate as raw materials, and KOH as a chemical activator and microwave absorber to rapidly synthesize a metal-free biocarbon aerogel catalyst with abundant cross-linked pores. Microwave treatment and sodium lignin sulfonate facilitate the introduction of thiophene S, C=O groups, and C vacancies, as well as the expansion of specific surface area.

[0006] The preparation steps of the above-mentioned biochar aerogel catalyst are as follows: α-cellulose, sodium lignosulfonate, and KOH are uniformly mixed in a mortar and placed in a 25 ml crucible. The mixture is then pyrolyzed in a household microwave oven at 650 W for 5 minutes. The resulting material is then washed with water and vacuum dried at 65 °C for 12 h to obtain the biochar catalyst. When the amount of α-cellulose is 0.5, 1.0, 1.5, and 2.0 g, and the corresponding amount of sodium lignosulfonate is 2.0, 1.5, 1.0, and 0.5 g, the prepared materials are named C1S4, C2S3, C3S2, and C4S1, respectively.

[0007] The reaction of catalyst-activated peroxymonosulfate (PMS) for the degradation of organic pollutants: The temperature of the constant-temperature magnetically stirred water bath was set to 25 °C. The initial pH was adjusted with 1 M sulfuric acid or sodium hydroxide. The catalyst and PMS were added to a 100 mL flask containing 50 mL of aqueous solution of organic pollutants to start the degradation reaction. 1 mL of the reaction solution was extracted at predetermined time intervals, filtered through a 0.25 µm microporous membrane, squeezed into a centrifuge tube containing 1 mL of methanol, and the concentration of organic pollutants was detected using a UV-Vis spectrophotometer.

[0008] The above-mentioned microwave-prepared bio-carbon aerogel catalyst is characterized by its simple and short preparation process, the rich three-dimensional aerogel framework, and abundant cross-linked pores. Compared with traditional pyrolysis methods, microwave treatment and the introduction of sodium lignosulfonate are beneficial to the introduction of C=O groups, thiophene S and C vacancies, and the expansion of specific surface area.

[0009] The application of the aforementioned microwave-prepared bio-carbon aerogel catalyst in the degradation of organic pollutants is characterized by: the metal-free bio-carbon aerogel catalyst C3S2 exhibiting high degradation efficiency for organic pollutants, achieving a removal efficiency of 99.9% for oxytetracycline hydrochloride within 15 minutes, with a rate constant as high as 0.818 min. -1 Within 15 minutes, the removal rates of methyl orange, tetracycline, methylene blue, and ciprofloxacin were 97.0%, 99.0%, 99.0%, and 89.0%, respectively, confirming that the C3S2 / PMS catalytic system has good removal capabilities for different organic pollutants.

[0010] The application of the above-mentioned microwave-prepared bio-carbon aerogel catalyst in the degradation of organic pollutants is characterized by: in the C3S2 / PMS catalytic system, 1 O2 is the main active substance for pollutant degradation. Attached Figure Description

[0011] Figure 1 (a) is the SEM image of C3S2. Figure 1 (b) shows the TEM image and particle size distribution of C3S2. Figure 1 (c) is a photo of the C3S2 aerogel catalyst taken with a mobile phone.

[0012] Figure 2 It is the X-ray diffraction (XRD) of catalysts C1S4, C2S3, C3S2, C4S1, C3S2-800 and C.

[0013] Figure 3 X-ray photoelectron spectroscopy (XPS) of catalysts C3S2, C, and C3S2-800. (a) Full spectrum, (b) C 1s, (c) O 1s, and (d) S 2p.

[0014] Figure 4 These are electron paramagnetic resonance (EPR) images of catalysts C3S2, C, and C3S2-800. Detailed Implementation

[0015] The present invention will be described in detail below with reference to specific implementation examples.

[0016] Implementation Case 1:

[0017] The specific preparation steps of biochar catalyst are as follows:

[0018] α-cellulose, sodium lignosulfonate, and KOH were uniformly mixed in a mortar and placed in a 25 ml crucible. The mixture was then pyrolyzed in a household microwave oven at 650 W for 5 minutes. The resulting material was washed with water and then vacuum dried at 65 °C for 12 h to obtain a biochar catalyst. When the amount of α-cellulose was 0.5, 1.0, 1.5, and 2.0 g, and the corresponding amount of sodium lignosulfonate was 2.0, 1.5, 1.0, and 0.5 g, the prepared materials were named C1S4, C2S3, C3S2, and C4S1, respectively. The difference between C3S2-800 and C3S2 is that C3S2-800 is pyrolyzed in a tube furnace at 800 °C under a nitrogen atmosphere for 2 hours, while C3S2 is pyrolyzed in a household microwave oven at 650 W for 5 minutes. Catalyst C is prepared by mixing 2.5 g of α-cellulose and 0.5 g of KOH in a homogeneous mixture without sodium lignosulfonate, followed by pyrolysis at 650 W for 5 minutes. The resulting material is then washed with water and vacuum dried at 65 °C for 12 hours. The specific surface areas of the prepared catalysts C1S4, C2S3, C3S2, C4S1, C3S2-800, and C are 530.29 m², respectively. 2 / g、712.31 m 2 / g、826.42 m 2 / g、730.87 m 2 / g, 546.70 m 2 / g、487.14m 2 / g.

[0019] Figure 1 (a) is the SEM image of C3S2. Figure 1 (b) shows the TEM image and particle size distribution of C3S2. Figure 1 (c) is a photo of the C3S2 catalyst taken with a mobile phone. Scanning electron microscopy (SEM) revealed that C3S2 exhibits a rich three-dimensional aerogel framework ( Figure 1 a). Transmission electron microscopy (TEM) images characterizing the C3S2 catalyst show that it possesses abundant inter-crosslinked pores. In contrast, conventional pyrolysis methods typically obtain biochar with a smaller specific surface area from densely structured cellulose. The formation of the aerogel porous structure can be attributed to: (1) the gases emitted during the pyrolysis of α-cellulose and sodium lignin sulfonate contribute to pore formation; and (2) the pores are generated after the KOH activator encapsulated in the biochar is washed. The aerogel structure of the C3S2 catalyst, captured by a mobile phone, demonstrates that the biochar aerogel catalyst is fluffy and lightweight.

[0020] Figure 2 The crystal structures of the prepared catalysts C1S4, C2S3, C3S2, C4S1, C3S2-800 and C were characterized by X-ray diffraction (XRD). Figure 2 The XRD values ​​of all catalysts ranged from 21.5 to 23.2. o and 44.1 o Broad peaks were observed in the vicinity, corresponding to the (002) and (100) crystal planes of graphite, indicating the successful synthesis of the carbon material. Compared with the C catalyst without the addition of sodium lignosulfonate, the diffraction peak of the graphite (002) crystal plane broadened with the gradual increase of the sodium lignosulfonate content, increasing from 21.5... o Moved to 23.2 o The broadening and shifting of the diffraction peaks indicate a gradual increase in defects and amorphous carbon structures in the catalyst. The presence of defects and amorphous carbon structures may be due to the significant distortion of the carbon lattice caused by the introduction of sodium lignin sulfonate during pyrolysis. Since sodium lignin sulfonate cannot be successfully carbonized into biochar under microwave treatment and in the presence of the activator KOH, the biochar formed from α-cellulose should further act as a microwave absorber to promote the carbonization of sodium lignin sulfonate. Compared with C3S2-800 obtained by conventional pyrolysis, the diffraction peaks of the (002) graphite crystal plane of C3S2 are significantly broadened, indicating that microwave pyrolysis is beneficial to the increase of defects and amorphous structures.

[0021] Figure 3 The surface composition and elemental valence states of representative catalysts C3S2, C, and C3S2-800 were determined using X-ray photoelectron spectroscopy (XPS). Figure 3XPS full spectra of C3S2, C, and C3S2-800 are shown, with very prominent peaks for C and O. S is observed in both C3S2 and C3S2-800, indicating the successful preparation of a sulfur-containing catalyst in the presence of sodium lignosulfonate. High-resolution XPS was performed to investigate the valence states of C, O, and S. C 1s can be resolved to 284.8, 286.3, and 288.2 eV, corresponding to C=C, C-OH / COC, and C=O, respectively. Figure 3 b). Compared to C without sodium lignosulfonate, the C=O characteristic peak in C3S2 increased, indicating that the introduction of sodium lignosulfonate is beneficial for the exposure of active sites in the catalyst and for increasing the specific surface area. The C=O peak of C3S2-800 was lower than that of microwave-assisted C3S2, indicating that conventional pyrolysis is unfavorable for C=O formation. O 1s exhibited three peaks at 531.2, 532.3, and 534.0 eV ( Figure 3 c), representing CO, C=O, and adsorbed oxygen, respectively. Compared to C, the C=O peak in C3S2 shifts to a lower binding energy, which may be related to the introduction of more C vacancies by sodium lignin sulfonate. In C3S2, the S 2p ( Figure 3 d) These peaks can be resolved to 168.6 and 169.7 eV, attributed to surface-bound sulfites and sulfates. The two peaks of thiophene S at 164.0 and 165.0 eV should be assigned to 2p, respectively. 3 / 2 and 2p 1 / 2 The S 2p peak intensity in C3S2 is significantly higher than that in C3S2-800, indicating that microwave pyrolysis is beneficial for the preservation of S-containing groups, thereby promoting the generation of reactive oxygen species during pollutant degradation.

[0022] Figure 4 Electron paramagnetic resonance (EPR) spectra of catalysts C3S2, C, and C3S2-800 further elucidated the defects in C3S2, C, and C3S2-800. A g-value of 2.003 confirmed the presence of C vacancies. C vacancies lead to an asymmetric charge distribution, changes in local density π-electrons, and increased chemical activity in carbon materials, thereby further promoting pollutant degradation by enhancing substrate adsorption and promoting PMS activation. Changes in C vacancy intensity indicate that sodium lignosulfonate and microwave treatment are favorable for C vacancy formation.

[0023] Implementation Case 2 (See Table 1, Item 1, Degradation of OTC by PMS)

[0024] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.6 g / L PMS was added to a 100 mL flask containing 50 mL of oxytetracycline hydrochloride (OTC) aqueous solution (10 mg / L) to initiate the reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer. It was found that the removal rate of OTC by PMS was less than 5% within 15 minutes.

[0025] Implementation Case 3 (See Table 1, Item 2, C3S2 Degradation of OTC)

[0026] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. It was found that the degradation rate of OTC by the C3S2 catalyst increased to 99.9% within 15 minutes, with a rate constant of 0.818 min⁻¹. -1 .

[0027] Implementation Case 4 (See Table 1, Item 3, Degradation of OTC by Catalyst C)

[0028] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer, revealing that the degradation rate of OTC by the C catalyst was 63.7% within 15 minutes.

[0029] Implementation Case 5 (See Table 1, Item 4, Degradation of OTC by C3S2-800)

[0030] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2-800 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2-800 catalyst was 73.5% within 15 minutes.

[0031]

[0032] Implementation Case 6 (See Table 2, Item 1, C1S4 Degradation of OTC)

[0033] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C1S4 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C1S4 catalyst was 80.0% within 15 minutes, with a rate constant of 0.332 min⁻¹. -1 .

[0034] Implementation Case 7 (See Table 2, Item 2, C2S3 Degradation of OTC)

[0035] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C2S3 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C2S3 catalyst was 99.0% within 15 minutes, with a rate constant of 0.463 min⁻¹. -1 .

[0036] Implementation Case 8 (See Table 2, Item 4, C4S1 Degradation of OTC)

[0037] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C4S1 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C4S1 catalyst was 94.0% within 15 minutes, with a rate constant of 0.271 min⁻¹. -1 .

[0038]

[0039] Implementation Case 9 (See Table 3, Item 1, Degradation of OTC by 0.06 g / L C3S2 for the reaction)

[0040] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.06 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 66.9% within 15 minutes, with a rate constant of 0.107 min⁻¹. -1 .

[0041] Implementation Case 10 (See Table 3, Item 2, Degradation of OTC by 0.08 g / L C3S2 for the reaction)

[0042] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.08 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 88.4% within 15 minutes, with a rate constant of 0.359 min⁻¹. -1 .

[0043] Implementation Case 11 (See Table 3, Item 4, Degradation of OTC by 0.12 g / L C3S2 for the reaction)

[0044] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.12 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 99.9% within 15 minutes, with a rate constant of 0.820 min⁻¹. -1 .

[0045]

[0046] Implementation Case 12 (See Table 4, Item 1, Effect of 0.4 g / L PMS on OTC Degradation)

[0047] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.4 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 75.0% within 15 minutes, with a rate constant of 0.153 min⁻¹. -1 .

[0048] Implementation Case 12 (See Table 4, Item 2, Effect of 0.5 g / L PMS on OTC Degradation)

[0049] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.5 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The degradation rate of OTC by the C3S2 catalyst was found to be 83.1% within 15 minutes, with a rate constant of 0.225 min⁻¹. -1 .

[0050] Implementation Case 13 (See Table 4, Item 4, Effect of 0.7 g / L PMS on OTC Degradation)

[0051] The temperature of the thermostatically heated magnetically stirred water bath was set to 25℃, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.7 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 99.5% within 15 minutes, with a rate constant of 0.200 min⁻¹. -1 .

[0052]

[0053] Implementation Case 14 (See Table 5, Item 1, Degradation of 5 mg / L OTC solution by C3S2 catalyst)

[0054] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (5 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 99.9% within 15 minutes, with a rate constant of 0.826 min⁻¹. -1 .

[0055] Implementation Case 15 (See Table 5, Item 3, Degradation of 15 mg / L OTC solution by C3S2 catalyst)

[0056] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (15 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 85.5% within 15 minutes, with a rate constant of 0.193 min⁻¹. -1 .

[0057] Implementation Case 16 (See Table 5, Item 4, Degradation of 20 mg / L OTC solution by C3S2 catalyst)

[0058] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (20 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The degradation rate of OTC by the C3S2 catalyst was found to be 75.0% within 15 minutes, with a rate constant of 0.123 min⁻¹. -1 .

[0059]

[0060] Implementation Case 17 (See Table 6, Item 1, C3S2 catalyst for OTC degradation at pH 2.4)

[0061] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 2.4 (adjusted with 1 M sulfuric acid). 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The degradation rate of OTC by the C3S2 catalyst was found to be 90.4% within 15 minutes, with a rate constant of 0.010 min⁻¹. -1 .

[0062] Implementation Case 18 (See Table 6, Item 2, C3S2 catalyst for OTC degradation at pH 5.6)

[0063] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 5.6 (adjusted with 1 M sulfuric acid). 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 92.6% within 15 minutes, with a rate constant of 0.260 min⁻¹. -1 .

[0064] Implementation Case 19 (See Table 6, Item 4, C3S2 catalyst for OTC degradation at pH 8.5)

[0065] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 8.5 (adjusted with 1 M sodium hydroxide). The degradation reaction was initiated by adding 0.10 g / L C3S2 catalyst and 0.6 g / L PMS to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L). At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 91.3% within 15 minutes, with a rate constant of 0.224 min. -1 .

[0066] Implementation Case 20 (See Table 6, Item 5, C3S2 catalyst for OTC degradation at pH 10.7)

[0067] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 10.7 (adjusted with 1 M sodium hydroxide). The degradation reaction was initiated by adding 0.10 g / L C3S2 catalyst and 0.6 g / L PMS to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L). At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 85.8% within 15 minutes, with a rate constant of 0.195 min⁻¹. -1 .

[0068]

[0069] Implementation Case 21 (See Table 7, Item 1, C3S2 catalyst for OTC degradation at 15 °C)

[0070] The temperature of the thermostatically heated magnetically stirred water bath was set at 15 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 69.2% within 15 minutes, with a rate constant of 0.144 min. -1 .

[0071] Implementation Case 22 (See Table 7, Item 2, C3S2 catalyst for OTC degradation at 20 °C)

[0072] The temperature of the thermostatically heated magnetically stirred water bath was set to 20 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 84.7% within 15 minutes, with a rate constant of 0.241 min. -1 .

[0073] Implementation Case 23 (See Table 7, Item 4, C3S2 catalyst for OTC degradation at 30 °C)

[0074] The temperature of the thermostatically heated magnetically stirred water bath was set to 30 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then detected at 352 nm using a UV-Vis spectrophotometer. The results showed that the C3S2 catalyst achieved a 99.9% degradation rate of OTC within 15 minutes, with a rate constant of 0.819 min⁻¹. -1 .

[0075]

[0076] Implementation Case 24 (See Table 8, Item 1, C3S2 catalyst for OTC degradation in the presence of humic acid (HA))

[0077] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. The degradation reaction was initiated by adding 0.10 g / L C3S2 catalyst, 0.2 g / L humic acid solution, and 0.6 g / L PMS to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L). At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 89.7% within 15 minutes.

[0078] Implementation Case 25 (Reaction see Table 8, Item 2, H2PO4 present)- (C3S2 catalyst for OTC degradation)

[0079] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 10 mM of H2PO4 were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L). - The degradation reaction was initiated with the solution and 0.6 g / L PMS. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into centrifuge tubes containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer, revealing a 91.7% degradation rate of OTC by the C3S2 catalyst within 15 minutes.

[0080] Implementation Case 26 (Reaction see Table 8, Item 3, SO4 present) 2- (C3S2 catalyst for OTC degradation)

[0081] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 10 mM SO42 were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L). 2- The degradation reaction was initiated with the solution and 0.6 g / L PMS. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into centrifuge tubes containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer, revealing a 92.4% degradation rate of OTC by the C3S2 catalyst within 15 minutes.

[0082] Implementation Case 27 (Reaction see Table 8, Item 4, Cl is present) - (C3S2 catalyst for OTC degradation)

[0083] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 10 mM Cl- were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L). - The degradation reaction was initiated with the solution and 0.6 g / L PMS. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into centrifuge tubes containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer, revealing a 93.0% degradation rate of OTC by the C3S2 catalyst within 15 minutes.

[0084] Implementation Case 28 (Reaction see Table 8, Item 5, NO3 present) - (C3S2 catalyst for OTC degradation)

[0085] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 10 mM of NO3 were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L). - The degradation reaction was initiated with the solution and 0.6 g / L PMS. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into centrifuge tubes containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer, revealing a 92.6% degradation rate of OTC by the C3S2 catalyst within 15 minutes.

[0086]

[0087] Implementation Case 29 (Reactions are shown in Table 9, Items 1-5, Cyclic Degradation of Oxytetracycline Hydrochloride (OTC) by C3S2 Catalyst)

[0088] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of OTC in the solution was then measured at 352 nm using a UV-Vis spectrophotometer. The results showed that the degradation rate of OTC by the C3S2 catalyst was 99.9% within 15 minutes. After centrifugation, the degradation efficiency of the catalyst for OTC remained above 90% in the first three cycles, reaching 73.0% in the fourth cycle and 61.0% in the fifth cycle.

[0089]

[0090] Implementation Case 30 (See Table 10, Item 1, Degradation of Methyl Orange (MO) by C3S2 Catalyst)

[0091] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a flask containing 50 mL of MO aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the MO solution was then measured at 463 nm using a UV-Vis spectrophotometer, revealing a 97.0% degradation rate of MO by the C3S2 catalyst within 15 minutes.

[0092] Implementation Case 31 (See Table 10, Item 2, Degradation of Tetracycline (TC) by C3S2 Catalyst)

[0093] The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a flask containing 50 mL of TC aqueous solution (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the TC solution was then measured at 357 nm using a UV-Vis spectrophotometer, revealing a 99.0% degradation rate of TC by the C3S2 catalyst within 15 minutes.

[0094] Implementation Case 32 (See Table 10, Item 3, Degradation of Methylene Blue (MB) by C3S2 Catalyst)

[0095] The temperature of the thermostatically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and 0.6 g / L of PMS were added to a flask containing 50 mL of MB (10 mg / L) to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the MB solution was then measured at 630 nm using a UV-Vis spectrophotometer, revealing that the degradation rate of MB by the C3S2 catalyst was 99.0% within 15 minutes.

[0096] Implementation Case 33 (See Table 10, Item 4, Degradation of Ciprofloxacin (CIP) by C3S2 Catalyst)

[0097] The temperature of the thermostatically stirred water bath was set to 25 °C, and the initial pH was 6.8. The degradation reaction was initiated by adding 0.10 g / L C3S2 catalyst and 0.6 g / L PMS to a flask containing 50 mL of CIP aqueous solution (10 mg / L). At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the CIP solution was then detected at 278 nm using a UV-Vis spectrophotometer, revealing that the C3S2 catalyst achieved a CIP degradation rate of 89.0% within 15 minutes.

[0098]

[0099] Implementation Case 34 (Reactions are shown in Table 11, the effect of different quenchers on OTC degradation)

[0100] Methanol (MeOH) and tert-butanol (TBA) are commonly used as free radical quenchers. MeOH can quench SO42-. ·- and · OH, TBA can quench · OH, while p-benzoquinone (BQ) and curcumin (Cur) can quench O2, respectively. ·- and 1 O2. The temperature of the thermostatically heated magnetically stirred water bath was set to 25 °C, and the initial pH was 6.8. 0.10 g / L of C3S2 catalyst and excess quencher were added to a 100 mL flask containing 50 mL of OTC aqueous solution (10 mg / L), followed by the addition of 0.6 g / L PMS to initiate the degradation reaction. At predetermined time intervals, 1 mL of the reaction solution was extracted, filtered through a 0.25 µm microporous membrane, and squeezed into a centrifuge tube containing 1 mL of methanol. The concentration of the OTC solution was then measured at 352 nm using a UV-Vis spectrophotometer. The degradation rates of OTC by the C3S2 catalyst within 15 minutes were found to be 99.0%, 99.2%, 68.1%, and 30.9%, respectively, under the quenching effects of MeOH, TBA, BQ, and Cur. Quenching results showed that MeOH and TBA had no significant inhibitory effect on the degradation of OTC in the C3S2 / PMS system, while BQ and Cur had a significant inhibitory effect on the degradation of OTC, indicating that... 1 O2 is the main active substance for pollutant degradation.

[0101]

Claims

1. The application of a microwave-efficiently prepared bio-carbon aerogel catalyst in the degradation of organic pollutants, characterized in that: A simple microwave pyrolysis method was used to rapidly synthesize a metal-free biocarbon aerogel catalyst with abundant cross-linked pores, using low-cost, non-toxic plant biomass α-cellulose and sodium lignosulfonate as raw materials, and KOH as a chemical activator and microwave absorber. Microwave treatment and sodium lignosulfonate facilitate the introduction of thiophene S, C=O groups and C vacancies, as well as the expansion of specific surface area. The preparation steps of the above-mentioned biochar aerogel catalyst are as follows: α-cellulose, sodium lignosulfonate, and KOH are uniformly mixed in a mortar and placed in a 25 ml crucible. The mixture is then pyrolyzed in a household microwave oven at 650 W for 5 minutes. The resulting material is then washed with water and vacuum dried at 65 °C for 12 h to obtain the biochar catalyst. When the amount of α-cellulose is 0.5, 1.0, 1.5, and 2.0 g, and the corresponding amount of sodium lignosulfonate is 2.0, 1.5, 1.0, and 0.5 g, the prepared materials are named C1S4, C2S3, C3S2, and C4S1, respectively. The reaction of catalyst-activated peroxymonosulfate (PMS) for the degradation of organic pollutants: The temperature of the constant-temperature magnetically stirred water bath was set to 25 °C. The initial pH was adjusted with 1 M sulfuric acid or sodium hydroxide. The catalyst and PMS were added to a 100 mL flask containing 50 mL of aqueous solution of organic pollutants to start the degradation reaction. 1 mL of the reaction solution was extracted at predetermined time intervals, filtered through a 0.25 µm microporous membrane, squeezed into a centrifuge tube containing 1 mL of methanol, and the concentration of organic pollutants was detected using a UV-Vis spectrophotometer.

2. The application of the microwave-prepared bio-carbon aerogel catalyst according to claim 1 in the degradation of organic pollutants, characterized in that: The catalyst has a simple preparation process and a short preparation time. The catalyst exhibits a rich three-dimensional aerogel framework with abundant cross-linked pores. Compared with traditional pyrolysis methods, microwave treatment and the introduction of sodium lignosulfonate are beneficial to the introduction of C=O groups, thiophene S and C vacancies, as well as the expansion of specific surface area.

3. The application of the microwave-prepared bio-carbon aerogel catalyst according to claim 1 in the degradation of organic pollutants, characterized in that: The metal-free biocarbon aerogel catalyst C3S2 exhibits high degradation efficiency for organic pollutants, achieving a 99.9% removal efficiency of oxytetracycline hydrochloride within 15 minutes, with a rate constant as high as 0.818 min. -1 Within 15 minutes, the removal rates of methyl orange, tetracycline, methylene blue, and ciprofloxacin were 97.0%, 99.0%, 99.0%, and 89.0%, respectively, confirming that the C3S2 / PMS catalytic system has good removal capabilities for different organic pollutants.

4. The application of the microwave-prepared bio-carbon aerogel catalyst according to claim 1 in the degradation of organic pollutants, characterized in that: In the C3S2 / PMS catalytic system 1 O2 is the main active substance for pollutant degradation.

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