Magnetic Porous Carbon Research Articles

Green preparation of magnetic porous carbon by high value utilization of metallurgical waste liquid for efficient extraction of pesticide residues in the environment

Green preparation of magnetic porous carbon by high value utilization of metallurgical waste liquid for efficient extraction of pesticide residues in the environment

Comprehensive undergraduate experiment: determination of phenylurea herbicide in tea by magnetic solid-phase extraction-high performance liquid chromatography

Against the backdrop of the Ministry of Education's promotion of new agricultural science construction and interdisciplinary integration, a comprehensive chemistry experiment to enhance the practical skills of students in preparing biomass functional materials and detecting pesticide residues was designed. Natural loofah was utilized as a precursor in synthesizing nitrogen-doped magnetic porous carbon materials, which were then applied in a magnetic solid-phase extraction (MSPE) technique. Subsequently, high performance liquid chromatography (HPLC) was employed to analyze and detect the phenylurea herbicide monuron in tea. The experimental process included material synthesis, characterization, optimization of the MSPE conditions, adsorption performance studies, and HPLC, reflecting its scientific, systematic nature and providing a comprehensive learning platform for students. It not only deepens student understanding of the relationship between material characterization and application, but also improves their experimental design and problem-solving capacities. Moreover, by integrating cutting-edge science, ideological and political education, and experimental training, it not only stimulates student interest in scientific research and cultivates innovative thinking and practical skills, but also strengthens their feelings of social responsibility and historical mission. This approach realizes the comprehensive educational goals of experimental training and lays the foundation for nurturing high-quality talent with a global perspective and sense of social responsibility.

Valorization of Bambusa striata shavings into functional superparamagnetic material and its application in biodiesel production: Response surface optimization, kinetics, thermodynamics and economic assessment

Herein, a novel highly porous biomass-based (Bambusa vulgaris striata) magnetic solid acid catalyst was developed for the first time via simultaneous activation and magnetization followed by acid functionalization. The sulfonated magnetic porous carbon was utilized as a catalyst for transesterifying Jatropha curcas oil (JCO) to biodiesel under microwave irradiation. The synthesized catalyst was extensively characterized using VSM, XRD, FTIR, SEM, EDS, TGA, XPS, Raman spectroscopy, and AFM techniques. Through Response Surface Methodology (RSM), a maximal biodiesel yield of 98.8 % was achieved over optimal optimal parametric states (catalyst loading 8 wt%, MOMR 24:1, 50 min, 80 °C). NMR confirmed JCO biodiesel formation with a FAME content of 98.04 %, and GCMS provided insight into its chemical composition. A pseudo-first-order kinetic study revealed an activation energy (Ea) of 28.734 kJ mol1. Thermodynamic analysis showed endothermic and non-spontaneous behavior with ΔH#, ΔS#, and ΔG# values of 25.928 kJ mol1, −0.193 kJ mol1 K1, and 94.251 kJ mol1, respectively. The catalyst displayed good reusability, easy recoverability, and stability, maintaining 75.4 % oil conversion even after ten consecutive cycles. Life cycle cost analysis (LCCA) estimates biodiesel production cost of $0.60 per liter, emphasizing high commercial viability.

Study on the adsorption of Ce(III) on phosphonic acid functionalized ZIF-67@SiO2 magnetic porous carbon materials

A ZIF-67 composite SiO2 material (ZIF-67@SiO2) was synthesized using ethyl orthosilicate (TEOS) as a silicon source, followed by one-step carbonization to produce magnetic porous nitrogen-doped carbon material (MNPC@SiO2) using ZIF-67@SiO2 as a carbon precursor. Subsequently, the composite P-MNPC@SiO2 was obtained through functionalization with diethylphosphonoethyltriethoxysilane (DPTS), and its characteristics were analyzed. The adsorption properties of Ce(III) on MNPC@SiO2 and P-MNPC@SiO2 composites were investigated under various conditions through adsorption experiments. Kinetic, isothermal, and thermodynamic models were employed to analyze the adsorption mechanism of P-MNPC@SiO2 on Ce3+ and assess adsorbent stability and regeneration performance. The result shows that P-MNPC@SiO2 exhibited excellent adsorption capacity for Ce3+ and possessed magnetic properties conducive to recycling. Under optimized conditions, P-MNPC@SiO2 reached Ce(III) adsorption saturation within 20 min, with a maximum adsorption capacity of 342.52 mg/g, which was 1.9 times higher than that of the MNPC@SiO2 material. Data fitting shows that surface adsorption controls the rate-limiting step, and Ce(III) forms a monolayer adsorption on the surface of the adsorbent material. Furthermore, P-MNPC@SiO2 exhibits strong stability and regeneration properties.

Nitrogen-doped magnetic porous carbon nanospheres derived from dual templates-induced mesoporous polydopamine coated Fe3O4 for efficient extraction and sensitive determination of volatile nitrosamines by gas chromatography-mass spectroscopy

N-nitrosamines (NAs) are highly carcinogenic compounds commonly found in food, beverages, and consumer products. Due to their wide polarity range, it is challenging to find a suitable carbon adsorbent that can simultaneously adsorb and enrich both polar and nonpolar NAs with good recovery. In this study, nitrogen-doped magnetic mesoporous carbon nanospheres (M-MCN) were prepared and employed as an adsorbent for magnetic solid-phase extraction (MSPE) to extract and concentrate four NAs. The introduction of nitrogen functional groups enhanced the hydrophilicity of the carbon material, allowing M-MCN to achieve a balance between hydrophilicity and hydrophobicity, resulting in good recovery for both polar and nonpolar NAs. A method combining MSPE with gas chromatography-mass spectrometry (GC-MS) was developed for the determination of NAs in processed meat and alcoholic beverages. The method exhibited a good linear range (1–100 ng g−1, r2 > 0.9967) and trace-level detection (0.53–6.6 ng g−1). The recovery rates for the four NAs ranged between 85.7 and 110.7 %, with intra-day precision expressed as relative standard deviation (RSD) between 4.1 and 10.7 %, and inter-day precision between 4.8 and 12.9 %. The results demonstrated not only good accuracy and precision but also provided a new adsorbent for the enrichment of trace-level NAs in processed meat and alcoholic beverage samples.

Manipulating cellulose-based dual-network coordination for enhanced electromagnetic wave absorption in magnetic porous carbon nanocomposites

A novel dual-network coordination strategy was utilized to prepare carbon based magnetic porous EMW absorption nanocomposites with controllable magnetic particles deposition on carbon matrices. Due to the conversion of carboxymethyl cellulose (CMC) into Prussian blue (PB) through coordination with Fe3+, the deposition of Fe3+ gradually tends to aggregate. Consequently, significant changes occur in the polycrystalline structure of magnetic Fe3O4 particles in the pyrolysis products, including alterations in grain size, orientation, and the overall size of polycrystalline particle. Finally, the obtained Fe3O4 decorated porous carbon nanocomposites showed ultrawide effective absorption band of 6.7 GHz owing to the advantageous impedance matching and the synergistic dielectric and magnetic loss effects. Overall, this study offers valuable insights into the design and comprehension of magnetic porous nanocomposites for efficient EMW absorption through the regulation of polycrystalline structure by controllable coordination deposition.

Determination of sulfonamide antibiotics by magnetic porous carbon solid-phase extraction coupled with capillary electrophoresis

Sulfonamide antibiotics (SAs) have been widely used as antibacterial drugs for the prevention and treatment of livestock and poultry diseases, but they seriously threaten human health because they can accumulate in humans. Therefore, it is highly important to develop methods for monitoring sulfonamide residues in aquaculture and food. In this research, based on the generation of porous carbon (PC) by the pyrolysis of sodium citrate, magnetic porous carbon (PC@Fe3O4) was synthesized by a solvothermal method and used as an adsorbent for the magnetic solid-phase extraction of SAs. The effects of the proportion of PC in PC@Fe3O4, adsorbent dosage, adsorption time, eluent type, extraction pH, salt concentration and eluent dosage on the extraction efficiency were systematically studied. The adsorption performance and behavior of PC@Fe3O4 on SAs were evaluated using adsorption kinetics and adsorption isotherms, and the adsorption mechanism was preliminarily discussed. Under optimal conditions, combined with capillary electrophoresis diode array detection, a sensitive detection method for SAs was developed. The proposed method can be used for the determination of six SAs in fishpond water and milk samples, with a linear range of 0.5–200 ng mL−1, detection limits of 0.24–0.34 ng mL−1, and spiked recoveries of 85.9–109.0 %.

P507-modified magnetic porous carbon derived from metal-organic frameworks for efficient separation of zirconium(IV) and hafnium(IV)

Extractant-based solid phase extraction exhibit practical application potential for efficient separation of Zr(IV) and Hf(IV), where the key is to regulate the host–guest interaction between the guest extraction agents and the host matrices to obtain high performance. However, the current research on the host matrices of extraction agents is insufficient. Leveraging the tunability of metal–organic frameworks (MOFs), we successfully prepared a magnetic MOF-derived porous carbon (C(Zn/Co-ZIF)) with a high specific surface area and Co-Nx active sites as an excellent matrix. This was achieved by deliberately controlling the pore volume and microenvironment through a mixed precursor strategy and high-temperature pyrolysis method. Furthermore, as an excellent extractant for the separation of Zr(IV) and Hf(IV) in solvent extraction, 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl) ester (P507) was carefully selected to modify C(Zn/Co-ZIF) to obtain C(Zn/Co-ZIF)@P507 by impregnation. Impressively, the maximum adsorption capacities of C(Zn/Co-ZIF)@P507 for Zr(IV) and Hf(IV) were up to be 0.58 and 0.39 mmol/g, respectively, while exhibiting excellent separation coefficient. Further mechanism studies indicated that the combination of high specific surface area and abundant Co-Nx active sites of C(Zn/Co-ZIF) leaded to strong interaction with P507, resulting in the excellent adsorption and separation performance of Zr(IV) and Hf(IV) based on the coordination between phosphinic groups of P507 and Zr(IV)/Hf(IV).

The Use of Magnetic Porous Carbon Nanocomposites for the Elimination of Organic Pollutants from Wastewater

One of the most significant challenges the world is currently facing is wastewater treatment. A substantial volume of effluents from diverse sources releases numerous pollutants into the water. Among these contaminants, organic pollutants are particularly concerning due to the associated risk of being released into the environment, garnering significant attention. Rapid advancements in agriculture and industry on a global scale generate vast volumes of hazardous organic compounds, which eventually find their way into natural systems. Recently, the release of industrial wastewater has been increasing, due to the progress of numerous businesses. This poses a danger to humans and the environment, leading to environmental contamination. The application of carbon nanocomposites in applied nanotechnology has recently expanded due to their large surface area, substantial pore volume, low preparation cost, and environmental resilience. Expanding the use of nanomaterials in water treatment is essential, as magnetic carbon nanocomposites consistently demonstrate an efficient elimination of pollutants from water solutions. In the current study, we have highlighted the application of magnetic porous carbon nanocomposites in removing organic pollutants from wastewater.

Liquid-waste derived magnetic porous carbon sphere for effective removal of tetracycline from aqueous solution

Effective removal of tetracycline (TC) from wastewater is highly important while still faces challenges especially in adsorption capacity. Herein, a novel N-doped magnetic porous graphitic carbon sphere (N-MPGCS) adsorbent was fabricated by a green strategy using tannic acid (TA) as organic ligand and stainless steel pickling wastewater as metal source. Melamine was also introduced to increase nitrogen-containing functional groups. Among the obtained carbon spheres, N-MPGCS1–800 sample shows a large specific surface area (up to 922.78 m2 g−1), appropriate O/N functional groups, suitable sp2 carbon, and good magnetic responsivity. Benefiting from these merits, this optimal material exhibits a high Langmuir adsorption capacity (1005.5 mg g−1 at 45 °C) for TC, fast adsorption kinetics (5 min for adsorption equilibration time at 50 mg L−1), and good applicability towards pH (3−10) and co-existing ions. Besides, the excellent magnetism permits the convenient and rapid recovery of adsorbent from the adsorption system. Moreover, the high TC removal ratio (92.3% after three cycles) presents its outstanding regeneration. Adsorption studies and characterizations show that H-bond, π-π stacking, metal-organic complexation interactions, and pore-filling effect contribute to the adsorption together. In addition, N-MPGCS1–800 also shows good removal on enrofloxacin, moxifloxacin, and norfloxacin. This work proves that N-MPGCS material can serve as a potential adsorbent, and more importantly, it gives a new path for mining industrial waste to produce high-effective magnetic carbon materials.

Magnetic Porous Carbon from Biomass for Malachite Green Removal

For years, environment protection, especially how to purify industrial and agricultural wastewater, has been a disputable issue. The scarcity of water resources increases the urgency of wastewater recycling. Meanwhile, emitting wastewater into rivers and farmland deteriorated environmental issues. To solve this problem, a low-cost and efficient way to produce porous carbon which can adsorb organic solute and then be removed is being discussed in this report, aiming to separate organic pollutants from wastewater. In this report, ferric chloride, potassium carbonate, and biomass (like sawdust) are used to fabricate porous carbon. These ingredients all low-cost and easy to be found in usual laboratory, suggesting that it is simple to imitate this method. Porous carbon produced in this method has excellent specific surface area of 1517 m2/g, which has an adsorption capacity for MG (malachite green) aqueous solution of 988.6 mg/g in maximum.

A poly(2,6-diaminopyridine) functionalized magnetic porous carbon nanomaterial for extraction and determination of phenol, nitrophenols, and chlorophenols in water samples

Herein, for the first time, a new method for the simultaneous extraction of phenol (Ph), nitrophenols (NPs), and chlorophenols (CPs) as the priority pollutants was proposed using a magnetic porous carbon coated with poly(2,6-diaminopyridine). The analytes were separated/determined by an HPLC device coupled to a diode array detector. Magnetic porous carbon was obtained by the pyrolysis of MIL-53(Fe) as a precursor and then functionalized with a layer of poly(2,6-diaminopyridine). Next, the synthesized adsorbent was identified by various methods, including FT-IR, XRD, SEM, VSM, surface analysis, and TEM techniques. After that, the design of the experiment strategy was used to identify and optimize the extraction variables. The LODs and linear range were obtained in the range of 0.04–0.15 µg/L and 0.1–500 µg/L, respectively. The one-day RSDs and day-to-day RSDs were gained in the range of 4.2–9.5 % and 5.0–12.5 %, respectively. The enrichment factors and extraction recoveries were obtained in the range of 208–378 and 41.6–75.6 %, respectively. Eventually, the outlined method was employed to analyze diverse water/wastewater samples satisfactorily.

Bayberry-like bimetallic CoNi-MOF-74 derivatives/MXene hybrids with abundant heterointerfaces toward high-efficiency electromagnetic wave absorption

The flourishing development of electronic devices and radar detection technologies necessitates the urgent creation of high-efficiency electromagnetic wave (EMW) absorption materials with expansive absorption bandwidths. Although MXene has garnered significant interest in the domain of EMW absorption due to its tunable dielectric properties and structural designability, its high permittivity often results in poor impedance matching and a single loss mechanism, which makes it difficult to realize optimal EMW absorption capabilities. In this work, CoNi bimetallic metal–organic frameworks (MOFs) derived bayberry-like magnetic porous carbon (CoNiMPC)@carbon nanotubes (CNTs)/MXene (CNCM) hybrids were initially synthesized via simple solution precipitation, thermal treatment, and electrostatic self-assembly strategy. As anticipated, excellent EMW absorption characteristics were achieved by adjusting the ratio of CoNiMPC@CNTs and MXene. Multi-heterointerfaces consisting of zero-dimensional porous carbon, one-dimensional carbon nanotubes, and two-dimensional (2D) MXene, electrical/magnetic coupling effects, and polarization loss induced by abundant heterointerfaces endow the prepared CNCM hybrids with high-performance EMW absorption. Notably, the CNCM-7 hybrid material exhibits a minimum reflection loss (RLmin) of − 65.3 dB at 6.8 GHz with a mere 2.7 mm thickness and an effective absorption bandwidth (EAB, RL < −10 dB) of 5.0 GHz at a thickness of 1.27 mm. This study proposes a unique viewpoint and approach towards the design and preparing high-performance MXene-based EMW absorption materials.

Magnetic porous carbon material derived from imine-linked covalent organic frameworks for magnetic solid phase extraction of trace chlorine-containing herbicides in soil

Here, imine-linked covalent organic frameworks coated Fe3O4 microspheres were fabricated and employed as the self-template to prepare magnetic porous carbon material. The magnetic solid phase extraction (MSPE) performance of such magnetic covalent organic frameworks derived porous carbons (CMCOFs) were studied for the first time, and the improved MSPE performance was verified. The variations of chemical and material properties in the carbonization processes were studied, and it was found that the CMCOFs carbonated at 400°C exhibited highest adsorption efficiencies for chlorine-containing herbicides due to the formation of nitrile components at this stage. The CMCOFs retained high adsorption efficiencies (above 90 %) to chlorine-containing herbicides at wide pH range (3–12) and high salt concentration. The CMCOFs-based MSPE coupled with HPLC technique was in good potential for analysis of trace chlorine-containing herbicides in soil samples. Under the optimized conditions, this approach displayed short extraction and elution time (5 and 8 min) and low limits of detection (0.35–5.5 ng/mL) for chlorine-containing herbicides. The recoveries of spiked analytes and the relative standard deviations in real soil samples were 81.86 %–110.9 % and less than 5.92 %, respectively. This study provides an efficient method for the analysis of trace chlorine-containing herbicides in complex samples, as well as give some inspiration on material modulation by controlled carbonization to achieve improved sorption performances.

ZIF-8-derived magnetic FCZ@C-600 composite for efficient adsorptive removal of unsymmetrical dimethylhydrazine from wastewater

Efficient and convenient removal of hazardous unsymmetrical dimethylhydrazine (UDMH) remains challenging for ecological security and human health. In this work, ZIF-8-derived magnetic porous carbons (FCZ@Cs) were synthesized via layer-by-layer self-assembly and pyrolysis using chitosan as an external carbon source. The optimal pyrolysis temperature of FCZ@Cs is 600 °C and the maximum adsorption capacity of FCZ@C-600 for UDMH is 185.70 mg/g at 298 K. Moreover, FCZ@C-600 has wide pH adaptability and good resistance to acid, natural organic matter, and interfering ions. UDMH adsorption onto FCZ@C-600 and ZIF-8-600 conforms to pseudo-second-order and Langmuir models. Thermodynamic studies demonstrate that the adsorption performance is endothermic and favorable. Mechanisms investigations further identify electrostatic interactions, diffusion, and hydrogen/coordination bonds as the greatest contributors to UDMH adsorption. Notably, magnetic FCZ@C-600 can be readily separated by a magnet and exhibits high stability with an adsorption capacity of 42.05 mg/g after six cycles. Furthermore, the leaching concentration of Fe and Zn can be as low as 0.3 mg/L and 1.0 mg/L (pH ≥ 4), respectively. UDMH wastewater after adsorption also shows good biosafety. This work provides insights into the development of emerging metal-organic framework-derived adsorbents with multifunctionality and good sustainability for efficient wastewater treatment.

Cu-Fe nanoparticles decorated rice hull/chitosan@FeAl2O4 to boosted peroxidase-like activity for catalytic degradation of antibiotics: Kinetics and mechanistic insights

A series of derived magnetic porous carbon skeleton-coated Cu/Fe nanocomposites (CunFe1-n@CRH-x) were synthesized using chitosan-rice hull waste-hercynite by an injection molding and impression method, which is introduced as a “treating wastewater by waste residuals” for environmental-friendly remediation. Specifically, the CRH-x is a unique platform for the growth of uniformly dispersed metal oxides with high catalytic performance. After that, the morphological and structural features of post-synthesized nanocomposites were fully identified by applying alternative analytical and spectroscopic tools. The peroxidase-like activity of catalysts via electron transfer process between the simultaneously surface-activated H2O2 and target contaminants (e.g., tetracycline (TC), naproxen (NPX), ciprofloxacin (CIP), and paracetamol (PC)) were evaluated in detail. In the following, to find interrelationships between catalytic performance and structural characteristics, environmental parameters, ions interface, long-term stability, reusability, removal pathway, and universality of the system in various water sources were investigated in detail. The excellent peroxidase-like activity of Cu0.6Fe0.4@CRH-400 can be related to the high Brønsted acid intensity, small pore size, high surface area, and dual-synergy of Cu-Fe nanocatalyst and H2O2. The Cu0.6Fe0.4@CRH-400 can be boosted electron transfer via the dual redox cycle of Cu2+/Cu+/Cu2+ and Fe3+/Fe2+/Fe3+ under its core–shell scaffold, which promoted the generation and/or conversion of active species (•OH2, O2•-) to •OH. 98.20 % of TC, 93.90 % of NPX, 92.10 % of CIP and 100 % of PC were degraded through a rate constant (and TOC (%) removal) of 0.0838 min−1 (51.10 %), 0.0897 min−1 (46.5 %), 0.0737 min−1 (42.30 %), and 0.1168 min−1 (54.6) in Cu0.6Fe0.4 @CRH-400/H2O2 system, respectively, which confirmed that the remediation follows pseudo-1st-order kinetic model. Additionally, the low activation energy of 22.04 kJ/mol and favorable ΔH (−19.60 kJ/mol) of TC degradation confirmed the effectiveness of the catalytic system. Importantly, the reaction pathway was proposed and then predicted the acute toxicity (oral LD50) and mutagenicity of the degradation intermediates. The fairly high degree of mineralization, high anti-interferences, broad-spectrum remediation capacity, adaptability to predominant environmental conditions, and wide pH range (3.0–9.0) by Cu0.6Fe0.4 @CRH-400/H2O2 system in the various real water matrices further endorsed the superiority of the catalytic system.

Iron-Cobalt magnetic porous carbon beads activated peroxymonosulfate for enhanced degradation and Microbial inactivation

Magnetic carbon-based catalysts are promising materials for advanced oxidation processes, offering both high catalytic activity and environmental friendliness, and hold great potential in environmental remediation. In this work, Fe and Co zeolite imidazole frameworks (ZIFs) derived micron-sized magnetic porous carbon beads (MPCBs) were prepared by phase inversion and following the carbonization procedure, and the morphological and structural characteristics of the MPCBs were confirmed. The presence of pores and channels in the MPCBs provides a specific microenvironment for the for the catalysis of the core. Bisphenol A (BPA) was selected for the targeted pollutant, and the catalytic experiments confirmed that the effective catalytic activity of MPCBs in the presence of peroxymonosulfate (PMS), which could almost completely degrade BPA in 20 min with a reaction rate of 0.368 min−1. Furthermore, the MPCBs were used to effectively bacterial inactivation. Intermediate products of the BPA degradation process were validated and the toxicological studies showed a gradual decrease in toxicity, indicating effective reduction of potential hazards. The macroscopic preparation methods we developed for MPCBs that is promising for industrial applications and has the potential to cope with complex environmental remediation.

One-step preparation of magnetic N-doped sodium alginate-based porous carbon and efficient adsorption of bisphenol A.

To resourcefully utilize algal biomass and effectively remove bisphenol A (BPA) from water, sodium alginate (SA) was prepared as the nitrogen-doped magnetic porous carbon material (SAC/N/Fe) with well-developed pore structure according to a one-step method using K2CO3, melamine, Fe(NO3)3·9H2O as the activator, nitrogen dopant, and magnetic precursor, respectively, in this study. The best product, SAC/N/Fe-0.2, was obtained by adjusting the mass ratio of raw materials, and its specific surface area and pore volume were 2240.65 m2g-1 and 1.44 cm3g-1, respectively, with a maximum adsorption capacity of 1248.23mgg-1 for BPA at 308K. SEM, XRD, XPS, VSM, and FT-IR characterization confirmed that the iron was successfully doped, giving the porous carbon a magnetic separation function. The adsorption process of BPA was more consistent with the Langmuir model and the proposed secondary kinetics, and the adsorption effect was stable and efficient in a wide pH range and under the interference of different metal ions. At the same time, the porous carbon was easy to separate and recover with good regeneration performance.

Magnetic porous carbon materials derived from metal-organic framework in-situ growth on natural cellulose of wood for sulfadiazine degradation: Role of delignification and mechanisms

Magnetic porous carbon materials as peroxymonosulfate (PMS) activators for sulfadiazine degradation were derived from metal-organic frameworks (MOFs) grown in-situ on the cellulose of wood through the one-step pyrolysis method. The cellulose was obtained by treating wood powder with sodium chlorite to remove lignin, and Fe-MOFs (MIL-101(Fe)) nanoparticles were in-situ grown on the cellulose through hydrothermal reaction. The delignification of wood effectively enhanced the in-situ growth of MIL-101(Fe) on the wood tracheid skeleton, increased the specific surface area of magnetic porous carbon material (Fe@PC-50) after pyrolysis, and improved the performance of Fe@PC-50 as a PMS activator for the degradation of sulfadiazine. With the presence of 0.04 g L−1 Fe@PC-50 and 0.12 g L−1 PMS, the degradation percentage of sulfadiazine (20 mg L−1) could reach 100 % within 15 min, indicating excellent catalytic activity. Quenching tests and electron paramagnetic resonance (EPR) indicated that both free and non-free radicals played important roles in PMS activation. X-ray photoelectron spectroscopy (XPS) suggested that Fe0 and Fe3C were the possible important active sites for sulfadiazine degradation. This work offered an effective method to synthesize PMS activators from biomass/MOF materials for water treatment.

Performance and mechanism of antibiotic removal by MOF-on-MOF-derived cobalt and nitrogen-doped magnetic porous carbon activated PMS

In this work, magnetic porous carbon material doped with cobalt and nitrogen (Co@N-MC) was obtained by pyrolysis of ZIF-67@ZIF-8. Various characterization techniques were used to investigate the material properties and cobalt was found to exist as Co0, Co2+, and Co3+. The efficiency of catalytic activation of peroxymonosulfate (PMS) for tetracycline (TC) degradation was investigated and 91.27 % of TC was degraded within 30 min using 0.2 g/L PMS and 0.04 g/L Co@N-MC. Furthermore, the effect of different factors on TC removal from the Co@N-MC/PMS system was examined and it was found that Co@N-MC maintained good catalytic activity and decent anti-interference ability. Additionally, the free radical quenching, electron paramagnetic resonance (EPR) experiments and linear sweep voltammetry (LSV) tests revealed that Co@N-MC activates PMS mainly through radical pathways (sulfate radical, hydroxyl radical and superoxide radical) and non-radical pathways (singlet oxygen、electron transfer), of which the latter is dominant. An examination of the stability of the material revealed that cobalt leaching (0.308 mg/L) was below the national China Emission standard. Possible TC degradation pathways were also proposed. Biotoxicity of major intermediates and end products was significantly reduced compared to TC. Overall, this study provides a novel approach for the preparation of non-uniform cobalt-based catalysts with high efficiency and low cobalt leaching for the activation of PMS.