Removal Of Norfloxacin Research Articles

Enhancement of norfloxacin degradation by citrate in S-nZVI@Ps system: Chelation and FeS layer

The degradation of organic pollution by sulfur-modified nano zero-valent iron(S-nZVI) combined with advanced oxidation systems has been extensively studied. However, the low utilization of nZVI and low reactive oxygen species (ROS) yield in the system have limited its wide application. Herein, a natural organic acid commonly found in citrus fruits, citric acid (CA), was combined with the conventional S-nZVI@Ps system to enhance the degradation of norfloxacin (NOR). The addition of CA increased the NOR removal by about 31% compared with the conventional S-nZVI@Ps system under the same experimental conditions. Among them, the enhanced effect of CA is mainly reflected in its ability to promote the release of Fe2+ and accelerate the cycling of Fe2+ and Fe3+ to further improve the utilization of nZVI and the generation of ROS; it also promotes the dissolution of the active substance (FeS) on the surface of S-nZVI to further improve the degradation rate of NOR. More importantly, the chelate of CA and Fe2+ (CA-Fe2+) had higher reactivity than alone Fe2+. Free radical quenching and electron spin resonance (ESR) experiments indicated that the main ROS for the degradation of NOR in the CA/S-nZVI@Ps system were SO4•- and OH•. CA-bound sulfur-modifying effects on NOR degradation was systematically investigated, and the degradation mechanism of NOR in CA/S-nZVI@Ps system was explored by various techniques. Additionally, the effect of common anions in water matrix on the degradation of NOR in CA/S-nZVI@Ps system and its degradation of various pollutants were also studied. This study provides a new perspective to enhance the degradation of pollutants by S-nZVI combined with advanced oxidation system, which can help to solve the application boundary problem of S-nZVI.

Synthesis of mesoporous MIL-100(Fe) from acid mine drainage sludge for norfloxacin removal: Industrial sludge high value utilization, adsorbent performance and contaminant removal mechanisms

Recovery of heavy metals from acid mine drainage sludge (AMDs) and their conversion into high value-added materials such as metal-organic frameworks (MOFs) is of great significance for sustainable development. MOFs have broad application prospects in liquid phase pollutant removal, owing to super high specific surface area and adjustable structure. In this study, MIL-100(Fe) with mesoporous structures was successfully prepared from AMDs by acid leaching-hydrothermal method. And the obtained MIL-100(Fe) was employed as an adsorbent for adsorptive norfloxacin (NOR) removal from wastewater. The adsorption results showed that the maximum adsorption capacity can reach 280.84 mg/g under the condition of 298 K, the initial pH value of solution is 10 and the dosage of catalyst is 0.1 g/L. According to the N2 sorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) characterization, the adsorption mechanism of NOR on MIL-100(Fe) is mainly attributed to electrostatic interaction, π-π stacking, pore filling and coordination. Furthermore, the adsorbent maintained 75.05% of its initial adsorption capacity after 5 cycles, indicating that MIL-100(Fe) has excellent stability. This study provides a new idea for the resource utilization of industrial sludge.

Removing Norfloxacin from Aqueous Solutions Using Biochar Derived from Waste Disposable Bamboo Chopsticks

The presence of antibiotics in water environments increases the resistance of bacterial and can also cause irreversible damage to ecosystems and the human body. In this study, disposable bamboo chopsticks were used as raw material to prepare bamboo biochar (BB) via oxygen-limited pyrolysis to remove norfloxacin (NOR) from aqueous solutions. The properties of the BB were explained through the characterization of its SBET, morphology, structure, and functional groups. The effects of the dosage, pH, ionic strength, and water type on the removal of NOR using BB were investigated. The maximum theoretical adsorption capacities (Qmax) of NOR removed by BB at 25, 35, and 45 °C obtained using the Langmuir model were 76.17, 77.22, and 105.19 mg/g, respectively. To facilitate a comparison with other types of biochar, this study also prepared biochar of rice straw, wheat straw, soybean straw, corn straw, rape straw, peanut shell, Eichhornia crassipes, and other biomass raw materials under the same preparation conditions as the BB. The results demonstrated that the removal rate of NOR using BB was the highest under the same adsorption conditions, reaching 99.71%. Biochar from waste disposable bamboo chopsticks can be used for the treatment of new types of pollutants in water bodies, such as antibiotics and other organic contaminants, which will help to achieve sustainable solid waste management.

Solvothermal Synthesis of Fe3+‐doped Cu2O Photocatalyst for Norfloxacin Removal from Water

AbstractPhotocatalytic technology has great potential in water pollution treatment. Prepared Fe3+‐doped Cu2O photocatalyst using solvothermal method successfully in this paper. Analyze and test the prepared samples and study their photocatalytic performance. The prepared samples have high purity and their morphology has undergone changes. By introducing Fe3+, the specific surface area of the sample increases and the absorption of visible light significantly increases. Further research found that the degree of hole separation of photogenerated electrons is obviously improved, this is due to a significant reduction in the surface resistance of the sample. The R2‐Cu2O degradation rate reached 80.5 % and it shows excellent photocatalytic performance.

Roles of extracellular polymeric substances in the adsorption and removal of norfloxacin during hydrothermal treatment of sewage sludge

Hydrothermal treatment (HT) is promising to remove antimicrobials from sewage sludge (SS); however, the mechanism of antimicrobial degradation during the HT of SS is not fully understood. In this study, the roles of extracellular polymeric substances (EPS) in the removal and transformation of norfloxacin (NOR) during the HT of SS at temperatures of 100 and 160 °C were investigated. The results indicated that the degradation of NOR increased with increasing HT temperature, with maximum NOR removal (52%) achieved at 160 °C. Furthermore, the NOR in sludge showed higher degradation efficiencies than the control as HT temperature was higher than 120 °C. Evident promotion effects of bound-EPS (B-EPS) in sludge were observed on the NOR degradation as HT temperature was higher than 120 °C, leading to the mineralization and deamination of protein-like components in EPS during HT. Beside, the adsorption capacity of NOR during the HT of SS decreased at temperatures higher than 120 °C. The evolution of the spatial structure of B-EPS was predominantly responsible for the adsorption of antimicrobials, a spontaneous process driven mainly by hydrophilic interactions. With the hydrothermal conversion of B-EPS, the electron transfer, and reactive species (3EPS* and ·OH) derived from B-EPS could facilitate the degradation of NOR. In particular, hydrogen bonds between B-EPS and NOR increased the apparent yield of ·OH and accelerated the decarboxylation of NOR during HT at temperatures higher than 120 °C. A toxicity evaluation suggested that HT for NOR degradation could attenuate toxicity, whereas deep oxidation or mineralization would be needed to promote ecosystem safety. These findings provide new insights into the hydrothermal activation of EPS and the interrelated hydrothermal fate of antimicrobials and other toxic pollutants in sludge.

Degradation of norfloxacin by sulfur-doped iron-cobalt oxides activated perodisulfate: Synergism between free radicals and singlet oxygen

The present investigation involved the synthesis of sulfur-doped CoFe2O4 (S-CoFe2O4) catalysts by a straightforward co-precipitation and calcination technique. These catalysts were subsequently employed for the degradation of norfloxacin (NOR) utilizing activated perodisulfate (PDS). At the optimal level of sulfur doping, the efficiency of NOR removal in the S-CoFe2O4-3/PDS system can achieve a high percentage of 98.2%. Furthermore, the study also examined the impact of starting pH, catalyst dosage, PDS dose, several common inorganic anions, and humic acid on the breakdown of NOR. The study of free radicals and singlet oxygen activation mechanisms in the S-CoFe2O4/PDS system is facilitated through the implementation of free radical quenching experiments and electron paramagnetic resonance (EPR) techniques. The suggested breakdown mechanism of NOR in the S-CoFe2O4/PDS system was determined through the analysis of degradation products using high-performance liquid chromatography-mass spectrometry (HPLC-MS). The Biotoxicity Analysis Software (TEST) was employed to assess the toxicity of NOR and its breakdown products.

Catalytic microenvironment regulation by introducing biochar into MIL-101Fe derivative for enhanced persulfate activation: Efficient antibiotic removal and RSM optimization

Persulfate-based advanced oxidization process was widely investigated in antibiotic removal. MOFs-derived carbon was potential in activating persulfate, while the inevitable sintering and agglomeration effect of catalysts during carbonization resulted in reduced performance. Low-cost biochar was a desired carrier in designing functional composites. Herein, MIL-101Fe-derived carbon/biochar composites (MCB-900) were prepared via carbonizing MIL-101Fe/corn stalk composites. Biochar supporting achieved the dispersion of MIL-101Fe derivative avoiding the agglomeration effect, but also regulated the catalytic microenvironment with more accessible active sites, high porosity, and structural defects. Accordingly, MCB-900 exhibited more efficient norfloxacin (NOF) removal (96.44 %) than biochar (32.90 %) or MIL-101Fe-derived carbon (79.49 %) via exciting PDS by the transformation of Fe species and carbonyl groups. It was found that NOF degradation was ascribed to radical and non-radical oxidization (SO4•-, O2•-, and 1O2), involving two possible degradation pathways according to LC-MS. MCB-900/PDS system exhibited high anti-interference capability for pH (2–10) and anions (Cl-, HCO3–, H2PO4-), and was suitable for actual water matrixes and various organic pollutants removal. Further, with optimization by RSM, low dosages of PDS and MCB-900 could also reach high NOF removal (>95 %). Combining emerging MOFs with traditional biochar, this work provided an effective means and reference to design high-efficiency catalysts for antibiotic removal in water treatment.

Exploring the mechanism of norfloxacin removal and active species evolution by coupling persulfate activation with biochar hybridized Fe3O4 composites

In situ growth of dispersed active sites on substrates is a strategy for designing highly efficient catalysts for sulfate radical (SO4•−)-based advanced oxidation processes (SR-AOPs). Here, magnetic biochar composite (Fe3O4/BC) was fabricated as an activator to trigger PDS (peroxydisulfate) for norfloxacin (NOR) removal, achieving reliable NOR removal efficiency (>90%) within 10 min. Based on the synergistic effect between Fe3O4 and BC, the removal rate increases to 0.0265 L mg−1 min−1. Fe3O4/BC exhibited decent adaptability, stability, and recyclability toward affecting factors variation during PDS activation, attributed to the synergistic effect between Fe3O4 and BC. The electron transfer of magnetic Fe3O4 coupled with the adsorption and conduction function of carbon skeleton, which overcomes typical problems as crystal agglomeration, metal leaching, and catalysts recovery etc. The electron-rich Fe(II) sites promote the radical pathway by generating reactive oxygen species (ROS, •OH, SO4•− and O2•−), and radicals evolution contributing to the form of 1O2 in non-radical pathway. Under the effect of multipath in NOR degradation, HPLC-QTOF-MS spectroscopy and DFT calculation revealed the possible degradation pathway of NOR. In addition, according to toxicity prediction, the overall NOR contamination toxicity of NOR was effectively alleviated by Fe3O4/BC + PDS system. Overall, this study presents a promising composite in PDS activation and views the active species evolution in the NOR removal system, which is crucial for mechanism study in relevant research in the future.

Effective Use of Sugarcane-Bagasse-Derived KOH-Activated Biochar for Remediating Norfloxacin-Contaminated Water.

Bagasse-derived biochar (SCB750) was prepared at 750 °C using Chinese sugarcane bagasse as a carbon source and then modified with KOH for the removal of the antibiotic norfloxacin (NOR) from aqueous solutions. 3K-SCB750, prepared using a solid-to-liquid mass ratio of bagasse:KOH = 1:3, was found to have the best adsorption performance for NOR. Under the conditions of pH 5, 25 °C, 2.4 g L-1 adsorbent, and 300 mg L-1 NOR, its adsorption of NOR reached equilibrium (97.5% removal) after 60 min. The adsorption behaviours were in line with the quasi-second-order kinetic and Langmuir isotherm models, respectively. The maximum theoretical adsorption capacity reached up to 157.4 mg·g-1 at 40 °C. The thermodynamic parameters showed that the adsorption of NOR onto 3K-SCB750 was a spontaneous, endothermic, and physical process. In addition, Brunauer-Emmett-Teller analysis (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy were conducted to investigate the structural and adsorption properties of 3K-SCB750. Fourier transform infrared spectroscopy (FTIR) was also applied to understand the mechanism of adsorption of NOR onto 3K-SCB750. All of the results indicated that 3K-SCB750 had a large specific surface area of 1038.8 m2·g-1, an average pore size of 1.9 nm, and hierarchical structures with random pores and cracks for efficient removal of NOR. NOR adsorption mechanisms on 3K-SCB750 were related to the pore-filling effect and electrostatic attraction. Therefore, 3K-SCB750 biochar may be used as a promising adsorbent of antibiotics in wastewaters.

ZIF-67 grows in chitosan-rGO hydrogel beads for efficient adsorption of tetracycline and norfloxacin

In this study, a novel hydrogel bead (rGO@ZIF-67@CS) was synthesized by integrating ZIF-67 into a chitosan and reduced graphene oxide (rGO) dual-network system. This hydrogel was designed for efficient removal of tetracycline (TC) and norfloxacin (NOR) in single- and binary-solute systems. The adsorption experiments revealed that TC and NOR can be effectively removed over a wide range of pH (4–8), achieving maximum adsorption capacities of 1685.26 mg·g−1 at pH = 4 for TC and 1890.32 mg·g−1 at pH = 5 for NOR. The pseudo-second-order kinetic and Langmuir models better fitted the kinetic and isotherm data of both antibiotics, indicating a homogeneous adsorption process dominated by monolayer chemisorption. Even after five adsorption–desorption cycles, the adsorption efficiency of the two antibiotics remained above 80 %. In the binary systems, rGO@ZIF-67@CS simultaneously removed 92.68 % of TC and 82.46 % of NOR. Additionally, in practical applications, the fixed-bed system treated 320 mL of the TC solution and 290 mL of the NOR solution. Microscopic characterization suggested that the adsorption mechanisms were likely attributed to pore filling, π-π stacking, hydrogen bond interactions, and complexation.

Simultaneous removal of Norfloxacin, Ciprofloxacin, and copper from aqueous solution by chitosan and MXene functionalized graphene oxide ternary composite based on anion-synergistic interaction

Simultaneous removal of Norfloxacin, Ciprofloxacin, and copper from aqueous solution by chitosan and MXene functionalized graphene oxide ternary composite based on anion-synergistic interaction

Fabrication of Z-scheme ZnO/g-C3N4 heterojunction modified by silver nanoparticles for photocatalytic removal of Norfloxacin and Rhodamine B

A novel ternary photocatalyst with a Z-scheme heterojunction was successfully synthesized through the deposition of Ag nanoparticles onto the surface of a ZnO/g-C3N4 composite. The prepared photocatalysts were characterized by XRD, FT-IR, XPS, HRSEM, TEM, DRS, PL, EIS, TPC, and M-S. The photocatalytic performance of the as-synthesized photocatalysts was systematically investigated through the photodegradation of norfloxacin (NOR) and rhodamine B (RhB) under visible light irradiation. The photodegradation efficiency of 5% Ag/ZnO/g-C3N4 (5AZCN) composite photocatalyst reached 86.7% (480 min) and 98.0% (60 min) for NOR and RhB, respectively. Moreover, the apparent rate constants of the 5AZCN composite photocatalysts for NOR and RhB were found to be 3.4 and 22.2 times higher than that of the ZCN composite photocatalysts, respectively. The significantly enhanced photocatalytic performance was ascribed to the widened range of visible light response and the efficient separation and migration of carriers facilitated by the introduction of Ag nanoparticles that functioned as electron transfer mediators. Based on the free radicals quenching experiment and electron spin resonance (ESR) spectroscopy characterization, superoxide radicals (·O2−) were the main reactive species in the photodegradation process. Furthermore, the charge transfer process was proved to be a Z-scheme transfer mechanism. This work provides a promising approach to simply constructing novel efficient Z-scheme photocatalysts for the elimination of environmental pollutants.

An investigation on removal of ciprofloxacin and norfloxacin by phycoremediation with an emphasis on acute toxicity and biochemical composition

Ciprofloxacin (CIP) and norfloxacin (NOR) belong to the class of emerging contaminants that are frequently detected in the aquatic environment as a binary mixture, responsible for the development of antibiotic-resistant genes and antibiotic-resistant bacteria. This study aims to investigate five different algal species Chlorella vulgaris (Cv), Chlorella pyrenoidosa (Cp), Scenedesmus obliquus (So), Tetradesmus sp (T) and Monoraphidium sp (M) for their tolerance and removal of binary mixture. The effects on biochemical composition in the algal species concerning the binary mixture and its removal efficiency are first reported in this study. The acute toxicity (96 h EC50) values are in the order of So > Cp > T > M > Cv, Chlorella vulgaris is the most sensitive algal species with 17.73 ± 0.24 mg/L and Scenedesmus obliquus is the least sensitive algal species with 39.19 ± 0.79 mg/L. The removal efficiency of the binary mixture was found to be in the order of So > Cp > T > M > Cv, Scenedesmus obliquus removed CIP (52.4%) and NOR (87.5%) with biodegradation as the major contributing removal mechanism. Furthermore, less toxic biotransformed products were detected in Scenedesmus obliquus and the biochemical characterization revealed that the growth-stimulating effect is higher with lipid (35%), carbohydrate (18%), and protein (33%) providing an advantage in the production of valuable biomass.

The pH-sensitive transformation of birnessite and its effect on the fate of norfloxacin

Birnessite plays a crucial role in regulating the fate of contaminants in soil, which is affected by the crystal structure of birnessite. In this study, the transformation of triclinic birnessite to hexagonal birnessite was examined at various pH values, and their reactivity towards norfloxacin was investigated. The findings indicate that the conversion from triclinic birnessite to hexagonal birnessite occurs under pH conditions lower than 7. The lower of the solution pH where the birnessite formed, the higher the surface reactivity. Throughout the transformation process, the migration of Mn3+ and the increased interlayer protons generated more reactive oxygen species, which enhanced the surface reactivity towards norfloxacin. Specifically, at a conversion pH of 1, the norfloxacin removal rate significantly increases from 14% to 97% compared to triclinic birnessite. The mechanism of norfloxacin removal by triclinic and hexagonal birnessite is illustrated. These findings provide valuable insights into the dynamic transformation of birnessites in aqueous environments with varying pH values and their impact on norfloxacin removal.

Efficient adsorption and separation of norfloxacin from water by allophane aerogel microspheres

Norfloxacin contamination in the water environment has garnered international attention due to the dire risks it poses to ecosystems and public health. Aerogel can be easily extracted or separated from aqueous solutions, and it can be used for norfloxacin practical wastewater treatment. In this study, allophane and β-cyclodextrin were prepared as copolymers, and sodium alginate as a cross-linking agent to prepare allophane aerogel microspheres (A-M) for the efficient separation of norfloxacin in an aqueous environment. The A-M provides a highly three-dimensional porous structure, allowing norfloxacin to effectively penetrate the aerogels and enhancing their adsorption capacity. At pH = 7, the adsorption capacity of allophane microspheres on norfloxacin was 529 mg/g, which was 429 and 209 mg/g higher than that of β-cyclodextrin and allophane, respectively. Adsorption capacity after 5 regeneration cycles was 78.5% of the initial adsorbents. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis showed that the key adsorption mechanisms of A-M are surface complexation and hydrophobic interaction. Therefore, the prepared A-M materials are excellent adsorbents for the effective separation and removal of norfloxacin from the aquatic environment.

Removal of Quinolone Antibiotics from Wastewater by the Biochar-Based Sludge Adsorbent

Antibiotics have been detected in tiny environmental matrices all over the world, which caused a lot of concern. To solve this problem, biological treatment can be a low-cost and high-efficiency way. The use of biochar adsorbents made from the residual sludge of sewage for wastewater treatment can achieve pollutant removal while realizing pollutant reduction and reuse, which is of great significance for green development. In this study, a prepared biochar-based adsorbent (PBA) was modified and used for norfloxacin (NOR) removal. The composition of the adsorbent was characterized, and the influence of application factors on adsorption performance was investigated. After being modified and optimized, an overall removal efficiency of 84% was achieved for NOR in 4 h. The adsorption behavior was spontaneous and consistent with the Lagergren pseudo-second kinetic model and Langmuir model. The adsorption capacity of PBA reached 8.69 mg·L−1 for NOR. A total removal efficiency of 62% was obtained for five mixed quinolone antibiotics by PBA. The PBA could be well regenerated and reused five times. This study explored a new method of the bio-waste utilization of sewage sludge for antibiotic removal from wastewater.

Upcycling waste plastics into FeNi@CNTs chainmail catalysts for effective degradation of norfloxacin: The synergy between metal core and CNTs shell

Upcycling waste plastics into valuable products for eliminating hazardous contaminants in aquatic matrixes represents an attractive approach to addressing the urgent environmental crisis. Herein, the magnetic FeNi@CNTs chainmail catalysts were successfully fabricated from waste plastics via catalytic pyrolysis and employed for peroxymonosulfate (PMS) activation to efficiently degrade norfloxacin (NOR) during the advanced oxidation process. Results revealed that the amount of metal loading played a critical role in the physicochemical properties and catalytic activities of FeNi@CNTs. The optimal NOR removal efficiency (100%) was achieved via FeNi30@CNTs with moderate metal content, which was attributed to the synergy between metal core and CNTs shell. Fe-Ni alloy not only catalyzed the growth of CNTs, but also activated PMS to generate more reactive oxygen species. Furthermore, CNTs acted as quick electron transfer routes to speed up the catalytic reactions and protected the metal core from agglomeration. However, excess metal led to the agglomeration of particles outside CNTs, thus inhibiting NOR degradation. Moreover, FeNi30@CNTs exhibited good stability and reusability during the cyclic experiments. The possible mechanism was deeply discussed by quenching experiments, EPR, XPS, and LC-MS characterizations. This study provides a novel route of waste-to-waste remediation, making FeNi@CNTs an inexpensive and sustainable candidate in antibiotic degradation, and simultaneously opens up a new perspective to alleviate the environmental problems caused by waste plastics.

L-phenylalanine-assisted construction of hierarchically structured Fe(OH)3@Co2(OH)2CO3 with enhanced catalytic activities for the degradation of persistent organic pollutants

In this work, a flower-like Fe(OH)3@Co2(OH)2CO3 catalyst was prepared via the confinement effects provided by L-phenylalanine, which favored the heterostructure construction of active iron centers (Fe(OH)3) anchored on the Co2(OH)2CO3 nanosheet supports. Benefiting from the created electron-transfer interface and dual metal active sites, the limitation of redox cycling was broken and exhibited highly efficient catalytic activities, the optimal Fe(OH)3@Co2(OH)2CO3 catalyst showed comparable catalytic performance for the degradation of dye (degradation degree of 99% methylene blue and orange II within 18 min). In addition, the prepared catalysts were employed for the efficient removal of antibiotics (tetracycline (98.9%), norfloxacin (92.5%) and doxycycline hyclate (90.2%). Besides, the preferred nanofibrous composite membranes prepared by combination of nanofibrous membranes (NFMs) with Fe(OH)3@Co2(OH)2CO3 catalysts possessed considerable potential for large-scale MB removal (treatment capacity of 238.5 L m−2 and permeability of 191.8 L m−2 h−1 driven by gravity) and stability (182.7 L m−2 of treatment capacity was achieved in the third run). The strategy of construction of rapid interface-redox on the heterogenous catalysts was designed to enhance catalytic performance, which provided a promising chance for the efficiently large-scale removal of dyes and antibiotics.

Performance and mechanisms of photocatalysis of silver phosphate modified by carbon nanosheets doped with both nitrogen and boron for removal of norfloxacin

The photocatalyst technology based on silver phosphate (Ag3PO4) has excellent oxidation ability in the degradation of antibiotic pollutants due to its appropriate energy band structure. However, the high charge recombination efficiency limits the wide application of Ag3PO4. In this study, carbon nanosheets doped with both N and B (NBNS) have excellent charge distribution. The photoactivity of Ag3PO4 was optimized by combining NBNS. After 12 min, Ag3PO4 @NBNS achieved 100% degradation of norfloxacin (NOR), 8.6 times the degradation rate of Ag3PO4 monomer. In addition, NBNS, Ag3PO4 and Ag3PO4 @NBNS were characterized by SEM, TEM, XRD, Raman and XPS. It revealed that there was an intense interface interaction between Ag3PO4 and NBNS, and a built-in electric field (BIEF) was constructed at the interface to achieve rapid separation of photogenerated charges. The DFT calculations results indicated that the doping of B and N could reduce the work function of carbon nanosheets and increase their charge density, which would promote the formation of BIEF between the interface of Ag3PO4 and NBNS. The catalytic reaction mechanism of Ag3PO4 @NBNS was proposed. This work provides a novel photocatalyst for the efficient removal of antibiotics, and sheds light on the use of carbon materials to optimize silver phosphate based photocatalyst, as well as the design of new efficient visible light catalysts.

Construction of β-cyclodextrin modified Fe3O4 composites with enhanced peroxymonosulfate activation towards efficient degradation of norfloxacin

In the current research study, β-cyclodextrin modified Fe3O4 (β-CD@Fe3O4) superparamagnetic composite materials were synthesized using co-precipitation and ultrasonication methods, with β-CD acting as a coating material. The as-prepared material was employed as a heterogeneous catalyst for the activation of peroxymonosulfate (PMS) for the removal of norfloxacin (NOR). The catalytic activities of bare Fe3O4, β-CD@Fe3O4 composites, and the β-CD@Fe3O4/PMS system were compared under various parameters. Results revealed that the β-CD@Fe3O4/PMS exhibited higher catalytic activities, and a removal efficiency of 99.12% with a rate constant of 0.1576 min−1 was achieved in 30 min under optimum conditions ([catalyst] = 0.4 g/L, [PMS] = 4.0 mM, [NOR] = 30 mg/L, pH = 7.0). In particular, the larger surface area of β-CD@Fe3O4 (120 m2g−1) and the presence of additional reactive sites accelerated the activation of PMS in comparison to bare Fe3O4 (70 m2g−1) and thereby promoted the mineralization of NOR. The impact of various pivotal factors on NOR abatement was also studied. Scavenging results and the EPR technique revealed that the SO4•−, •OH, and O2•−radicals participated in the removal of NOR in the β-CD@Fe3O4/PMS system. The Fe3+/Fe2+/Fe3+ redox cycle in β-CD@Fe3O4 is used for the activation of PMS and generates radicles. The reusability results show excellent stability of the catalyst material, and a loss of 4.35% was observed after four cycles. The results revealed that the β-CD@Fe3O4 composites can activate PMS and have potential for the degradation of various pollutants from the environment.