Preparation method and application of cobalt nitrate modified Spartina alterniflora biochar

Abstract

A method for preparing and applying cobalt nitrate-modified Spartina alterniflora biochar belongs to the field of wastewater treatment technology. The steps are as follows: Spartina alterniflora powder is soaked in NaOH solution, then washed with deionized water until the pH reaches neutral, and dried in an oven to obtain NaOH-treated Spartina alterniflora biochar; the treated Spartina alterniflora biochar is stirred to fully disperse; then Co(NO3)2·6H2O is added, mixed, and stirred at room temperature to allow the Co... 2+ The cobalt nitrate-modified Spartina alterniflora biochar was thoroughly impregnated with NaOH to form a mixture. The mixture was dried in an oven, then pyrolyzed in a tube furnace at 850°C under N2 atmosphere at a rate of 5°C / min. After cooling, the product was removed, ground, and then cobalt nitrate-modified Spartina alterniflora biochar was obtained. This invention offers a simple and reproducible method, readily available biochar precursors, and low preparation costs, making it suitable for large-scale production. The resulting cobalt nitrate-modified Spartina alterniflora biochar shows promising application prospects in areas such as the treatment of organic pollution in aquatic environments.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and mainly relates to a method for preparing and applying cobalt nitrate-modified Spartina alterniflora biochar (SBC-Co).

[0002] The cobalt nitrate-modified Spartina alterniflora biochar prepared by this invention can degrade a variety of organic pollutants, especially tetracyclines, sulfonamides, quinolone antibiotics, and nonsteroidal anti-inflammatory drugs such as tetracycline hydrochloride, sulfamethoxazole, ciprofloxacin, and ibuprofen. Background Technology

[0003] With the continuous development of the modern pharmaceutical industry, the treatment of medical wastewater has become an increasingly important issue, posing a potential threat to human and ecological health. The drug components in environmental water bodies are often very complex, frequently containing multiple pollutants. Among these, tetracyclines, quinolones, sulfonamides, and nonsteroidal anti-inflammatory drugs (NSAIDs) are the four most commonly detected classes of drugs. Drug removal technologies from water bodies have become a research hotspot. Among these, advanced oxidation technologies based on biochar-activated persulfate have received widespread attention due to their high removal efficiency.

[0004] In recent years, with the continuous increase in efforts to control invasive alien species, the management of Spartina alterniflora has received much attention. Spartina alterniflora has a strong reproductive capacity, gradually consuming nutrients from native plants, disrupting the ecological balance, and posing a significant threat to local ecological security. Manual harvesting and mechanical removal are commonly used physical methods for removing Spartina alterniflora, but how to dispose of the harvested plant remains a problem. Spartina alterniflora is rich in organic carbon, cellulose, and various minerals, possessing excellent modification potential and making it an ideal raw material for biochar production. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing cobalt nitrate modified Spartina alterniflora biochar and its application. The cobalt nitrate modified Spartina alterniflora biochar prepared by this method can simultaneously and efficiently remove complex pollutants such as tetracyclines, sulfonamides, quinolone antibiotics, and nonsteroidal anti-inflammatory drugs, such as tetracycline hydrochloride, sulfamethoxazole, ciprofloxacin, and ibuprofen.

[0006] A method for preparing cobalt nitrate-modified Spartina alterniflora biochar includes the following steps: 12.5000 g ± 0.0005 g of Spartina alterniflora powder was added to 250 mL of 0.1 M NaOH solution and soaked for 6 h. It was then washed with deionized water until the pH reached neutral and dried in an oven for 24 h to obtain NaOH-treated Spartina alterniflora biomass. 3.0000 g ± 0.0005 g of the treated Spartina alterniflora biomass was weighed and fully dispersed under magnetic stirring. Then, 1.0000 g of Co(NO3)2·6H2O was added, and the mixture was continuously magnetically stirred at room temperature for 24 h to allow the Co...2+ The mixture is fully soaked in NaOH-treated Spartina alterniflora to form a mixture.

[0007] The mixture was dried in an oven and then transferred to a tube furnace. In the tube furnace, the temperature was increased to 850°C at 5°C / min under N2 atmosphere and pyrolyzed for 2 hours. After cooling, the product was taken out and ground to obtain cobalt nitrate modified Spartina alterniflora biochar.

[0008] The cobalt nitrate-modified Spartina alterniflora biochar prepared by this method can be used to simultaneously degrade and remove complex pollutants such as tetracyclines, sulfonamides, quinolone antibiotics, and nonsteroidal anti-inflammatory drugs, including tetracycline hydrochloride, sulfamethoxazole, ciprofloxacin, and ibuprofen.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Using the invasive plant Spartina alterniflora as a biochar precursor, and taking advantage of its high content of various elements such as C, H, O, N, P, S, and Ca, as well as its high cellulose content, it can effectively promote carbon formation and crystallization and provide certain oxygen-containing functional groups; providing a new approach to the management of invasive plants and realizing the resource utilization of waste.

[0010] 2. By pretreating Spartina alterniflora powder with a 0.1M NaOH solution, the surface of the powder becomes noticeably rough and pitted due to the etching effect of NaOH. This provides abundant attachment sites for the subsequent introduction of Co, enabling Co to be stably attached to the surface and pores of Spartina alterniflora biomass and avoiding the loss of effective active sites.

[0011] 3. High-temperature pyrolysis of carbon materials in an oxygen-deficient environment created by nitrogen effectively prevents the oxidation and combustion of biomass, increases yield, and helps control the pore structure and surface chemical properties of biochar.

[0012] 4. By introducing the transition metal Co, the structure of Spartina alterniflora biochar is regulated, and the surface active sites of cobalt nitrate-modified Spartina alterniflora biochar are significantly increased, which improves its activation ability for permonosulfate (PMS) and thus enhances its catalytic degradation performance for organic pollutants. The cobalt nitrate-modified Spartina alterniflora biochar prepared by this invention can efficiently degrade complex pollutants such as tetracyclines, sulfonamides, quinolone antibiotics, and nonsteroidal anti-inflammatory drugs, such as tetracycline hydrochloride, sulfamethoxazole, ciprofloxacin, and ibuprofen.

[0013] 5. The specific surface area of ​​cobalt nitrate-modified Spartina alterniflora biochar can reach 298.2841 m². 2 / g, pore volume up to 0.381734cm³ 2 With a pore size of up to 5.9441 nm and a high degree of graphitization, the cobalt structure is more ordered and the crystallinity is higher, giving it excellent ability to activate PMS.

[0014] 6. The method of this invention is simple, the operating conditions are controllable, the equipment requirements are low, the repeatability is good, the biochar precursor is easy to obtain, the preparation cost is low, and it is suitable for large-scale preparation. The cobalt nitrate modified Spartina alterniflora biochar obtained has good application prospects in the field of water environment organic pollution control. Detailed Implementation

[0015] A method for preparing cobalt nitrate-modified Spartina alterniflora biochar includes the following steps: 12.5000 g ± 0.0005 g of Spartina alterniflora powder was added to 250 mL of 0.1 M NaOH solution and soaked for 6 h. It was then washed with deionized water until the pH reached neutral and dried in an oven for 24 h to obtain NaOH-treated Spartina alterniflora biomass. 3.0000 g ± 0.0005 g of the treated Spartina alterniflora biomass was weighed and fully dispersed under magnetic stirring. Then, 1.0000 g of Co(NO3)2·6H2O was added, and the mixture was continuously magnetically stirred at room temperature for 24 h to allow the Co... 2+ The mixture is fully soaked in NaOH-treated Spartina alterniflora to form a mixture.

[0016] The mixture was dried in an oven and then transferred to a tube furnace. In the tube furnace, the temperature was increased to 850°C at 5°C / min under N2 atmosphere and pyrolyzed for 2 hours. After cooling, the product was taken out and ground to obtain cobalt nitrate modified Spartina alterniflora biochar.

[0017] Co 2+ It acts as a catalyst.

[0018] The cobalt nitrate-modified Spartina alterniflora biochar prepared by this method can be used to efficiently degrade complex pollutants such as tetracyclines, sulfonamides, quinolone antibiotics, and nonsteroidal anti-inflammatory drugs, including tetracycline hydrochloride, sulfamethoxazole, ciprofloxacin, and ibuprofen.

[0019] The degradation efficiencies of a mixed solution of tetracycline hydrochloride, sulfamethoxazole, ciprofloxacin and ibuprofen with a concentration of 5 mg / L were 100%, 100%, 100% and 93.17%, respectively, when the PMS concentration was 0.5 mM, the catalyst dosage was 0.1 g / L and the pH was 5.8.

[0020] In the degradation system of cobalt nitrate-modified Spartina alterniflora biochar, the free radical pathway (SO4• − •OH, O2• - ) and non-radical pathways 1 Degradation is achieved through the synergistic effect of O2; among which, the generation of non-free radicals is the main factor. 1 The degradation reaction, primarily driven by O2, initially involved Co... 2+It can break the -OO- bonds in PMS, generating •OH and SO4• − At the same time, it is converted into Co. 3+ ; the generated Co 3+ The ability to activate PMS is limited, resulting in the generation of SO5 with low oxidation potential. • - and Co 3+ Restore to Co 2+ H2O2 is generated by SBC-Co catalytic hydrolysis of PMS, and then by Co... 3+ •OH interacts with the generated H2O2 and further decomposes to form O2• - In the non-radical pathway 1 O2 can be generated by the C=O groups on the surface of SBC-Co, in addition 1 O2 can also be produced by O2• - The reactive oxygen species generated by the self-reaction ultimately achieve efficient degradation of tetracycline hydrochloride, sulfamethoxazole, ciprofloxacin, and ibuprofen.

Claims

1. A method for preparing cobalt nitrate-modified Spartina alterniflora biochar, comprising the following steps: 12.5000 g ± 0.0005 g of Spartina alterniflora powder was added to 250 mL of 0.1 M NaOH solution and soaked for 6 h. It was then washed with deionized water until the pH reached neutral and dried in an oven for 24 h to obtain NaOH-treated Spartina alterniflora biomass. 3.0000 g ± 0.0005 g of the treated Spartina alterniflora biomass was weighed and fully dispersed under magnetic stirring. Then, 1.0000 g of Co(NO3)2·6H2O was added, and the mixture was continuously magnetically stirred at room temperature for 24 h to allow the Co... 2+ The mixture was thoroughly soaked in NaOH-treated Spartina alterniflora to form a mixture; The mixture was dried in an oven and then transferred to a tube furnace. In the tube furnace, the temperature was increased to 850°C at 5°C / min under N2 atmosphere and pyrolyzed for 2 hours. After cooling, the product was taken out and ground to obtain cobalt nitrate modified Spartina alterniflora biochar.

2. The application of the cobalt nitrate modified Spartina alterniflora biochar prepared by the method of claim 1 in the degradation and removal of complex pollutants such as tetracyclines, sulfonamides, quinolone antibiotics, and nonsteroidal anti-inflammatory drugs.

3. The application of cobalt nitrate-modified Spartina alterniflora biochar according to claim 2 in the degradation and removal of complex pollutants such as tetracyclines, sulfonamides, quinolone antibiotics, and nonsteroidal anti-inflammatory drugs, characterized in that: The nonsteroidal anti-inflammatory drugs mentioned are tetracycline hydrochloride, sulfamethoxazole, ciprofloxacin, or ibuprofen.