Search Results (53)

The extensive use of oxytetracycline (OTC) poses significant threats to aquatic ecosystems, necessitating efficient removal strategies. While photocatalytic technology is a promising approach, single catalysts, like UiO-66-NH₂ and Bi₂MoO₆, suffer from rapid photogenerated carrier recombination and narrow light absorption. To address this, a Z-scheme heterojunction photocatalyst, Bi₂MoO₆/UiO-66-NH₂, was synthesized via a solvothermal method to enhance OTC degradation. Characterization results showed that the composite expanded visible-light absorption and improved electron-hole separation. Under simulated sunlight, the optimized composite (BUN80) achieved an OTC removal efficiency of 87.68% within 120 min under optimized conditions. The catalyst retained photocatalytic activity over five consecutive cycles, although a decrease in removal efficiency was observed. Radical trapping experiments indicated that h⁺ and •O₂⁻ were the main reactive species, and a proposed Z-scheme charge transfer pathway was suggested based on band structure analysis and photoelectrochemical results. LC-MS analysis identified 17 intermediate products, and ECOSAR-based toxicity prediction suggested a decreasing trend in aquatic toxicity during the degradation process. These findings indicate that Bi₂MoO₆/UiO-66-NH₂ is a promising photocatalyst for OTC degradation in water. Full article

Extensive animal production systems based on dryland pastures in Mediterranean regions have low profit margins. Improvements in soil fertility or grazing management and stocking rates are recognized strategies for reversing this situation and to ensure long-term agricultural sustainability. This article aims to assess whether this strategy of possible intensification of sheep production has a significant impact on soil compaction, which is a manifestation of soil functionality degradation resulting from trampling. An experimental design with four treatments was implemented (with and without dolomitic limestone application; continuous grazing with low stocking rates, CG-LSR, and deferred grazing with high stocking rates, DG-HSR). The study involved cone index (CI, in kPa) measurements (48 sampling areas, 12 in each treatment) on eight dates during two annual pasture/grazing cycles (2023/2024 and 2024/2025). Other soil parameters, the presence of trees and grazing preferences were also monitored and correlated with CI. The main results showed: (i) significantly higher soil compaction under CG-LSR than under DG-HSR; (ii) a negative and significant effect of soil moisture content (SMC) on CI (r = −0.381; p < 0.05); (iii) a significant CI increase in preferential grazing areas, but only in the topsoil layer (0–10 cm) and with a very weak correlation coefficient (r = 0.172; p < 0.05); and (iv) no significant differences in CI under and outside tree canopy areas (UTC and OTC, respectively) for the depth range of 0–30 cm. These results are good indicators of the desired and sustainable intensification of extensive livestock grazing systems. Full article

Urban densification in post-socialist cities has drastically reduced open and green spaces in high-rise housing areas (HRHAs), intensifying heat stress and degrading outdoor thermal comfort (OTC). These neighborhoods—shaped by socialist-era planning and, later, market-led infill—combine high built density, low greenery, and limited ventilation, making them critical testbeds for climate-adaptive regeneration. This study presents the first empirically validated ENVI-met assessment of blue–green infrastructure (BGI) performance in a post-socialist HRHA, using a representative courtyard in Niš, Serbia, during the 14 August 2024 heatwave. A 24 h field campaign (air temperature, humidity, wind speed, and mean radiant temperature) validated the model with high accuracy (R² = 0.92, RMSE = 1.1 °C for air temperature; R² = 0.88, RMSE = 3.5 K for Physiological Equivalent Temperature (PET). Four retrofit scenarios were simulated: S0 (existing), S1 (grass), S2 (grass + trees), and S3 (S2 + shallow pool). Across all scenarios, daytime PET indicated strong–extreme heat stress, peaking at 61.9 °C (16:00 h). The best configuration (S3) reduced PET by 2.68 °C (10:00 h) but <1 °C at peak hours, with acceptable comfort limited to 04:00–07:00 h. The results confirm that small-scale surface-level greening provides negligible thermal relief under a dense HRHA morphology. Urban morphological reform—optimizing height, spacing, ventilation, and integrated greening—is more effective for heat mitigation. Future work should include multi-seasonal field monitoring and human thermal-perception surveys to link microclimate improvement with exposure and health risk. Full article

With a complex molecular structure, oxytetracycline (OTC) has characteristics such as bioaccumulation and poor degradability. As a result, if it accumulates in the environment, it can cause bacteria to develop drug resistance, thereby affecting human health. There is a considerable cultivation area for macadamia nuts in southwestern China. This study mainly focuses on macadamia nut shells, preparing macadamia nut shell biochar (MBC) and cobalt-modified macadamia nut shell biochar (Co-MBC) for activating permonosulphate (PMS) to remove OTC in the water. To determine the optimal preparation conditions for the biochar, the effects of the pyrolysis temperature and the mass ratio of biomass to cobalt sulfate heptahydrate were investigated. The study shows that after modification, the surface roughness of the material increased, transforming into a micro-pore structure; thus, the specific surface area increases significantly and new functional groups appear on the surface. The optimal pyrolysis temperature for the biochar was determined to be 600 °C, and the optimal mass ratio of biomass to cobalt sulfate heptahydrate was 15:1. Under such conditions, the removal rate of OTC by a Co15-MBC600/PMS system in 20 min can reach 95.53%. The reaction mechanism involves pathways of the free radical (SO₄⁻) and non-free radical (¹O₂), and the Co²⁺/Co³⁺ cycle can promote the activation of PMS. Finally, the OTC can be mineralized into CO₂ and H₂O by reactions such as demethylation and decarboxylation. Co-MBC is highly effective and green and can be reused; therefore, it has good prospects for the removal of OTC in waste water. Full article

Ochratoxins (OTs) pose a major food safety threat, yet analytical methodologies and regulations focus almost exclusively on ochratoxin A (OTA), overlooking the toxic analogues OTB and OTC, especially in complex coffee and spice matrices. The present study addressed this gap by first systematically confirming the high cross-reactivity (>85%) of commercial OTA immunoaffinity columns (IACs) toward OTB and OTC. It was identified that conventional alkaline methanol extraction caused OTC degradation, and subsequently a stable and unified acetonitrile-water (8/2, v/v) extraction protocol was developed. To overcome severe matrix interference endemic to these foods, a novel 0.5% Tween-20-PBS IAC load and wash procedure was optimized. The resulting method was fully validated in representative roasted coffee and pepper matrices on both HPLC-FLD and UHPLC-MS/MS platforms, demonstrating excellent linearity (r > 0.999), accuracy (mean recovery 82.00–112.51%), and precision (RSD% ≤ 8.81%) across three spiked levels (0.3, 5, 10 µg/kg). While UHPLC-MS/MS achieved higher sensitivity (LOQs 0.1 µg/kg) than that of HPLC-FLD (LOQs 0.3 µg/kg), with isotope internal standards essential for correcting significant matrix effects. Application to forty commercial coffee and spice samples (19 coffee, 21 spice) revealed OTA contamination in 47.5% of products (up to 3.46 µg/kg) and co-occurrence of OTA/OTB in 3 of 8 cumin samples. This work establishes the first comprehensively validated IAC-based method for multi-OTs in complex foods, facilitating an urgently needed, robust tool for comprehensive risk assessment. Full article

This study reports the hydrothermal synthesis, characterization, and Fenton-like catalytic performance of CeO₂–CoFe₂O₄ nanocomposites for degrading Congo Red (CR) dye and the oxytetracycline (OTC) antibiotic. A series of Ce-doped cobalt ferrite samples was prepared using a hydrothermal reaction. Additionally, the 50Ce-CFO sample was further activated with H₂O₂ treatment. XRD, FTIR, and SEM analyses confirmed the formation of a spinel phase alongside segregated CeO₂, which acts as a grain-growth inhibitor. The increased Ce content promotes particle amorphization. FTIR showed changes in the intensity of the M–O stretching band, indicating Ce-induced bond polarization in the spinel lattice. In H₂O₂ decomposition tests, the 50Ce-CFO catalyst fully decomposes H₂O₂ in 160 min, while the activated sample completes it in 125 min. Fenton-like degradation of CR and OTC by untreated and activated 50Ce-CFO sample followed pseudo-first-order kinetics. Catalyst stability was confirmed using post-reaction XRD, FTIR, and SEM analyses. Incorporation of CeO₂ into CoFe₂O₄ refines the crystallite size, increases the BET surface area, and enhances adsorption capacity, while the Ce⁴⁺/Ce³⁺ redox couple promotes reactive oxygen species generation. Owing to this dual structural and catalytic role, the CeO₂-CoFe₂O₄ composites exhibit significantly improved Fenton-like catalytic activity, enabling the efficient degradation of organic pollutants. Full article

The increasing presence of tetracycline antibiotics (TCs) in water sources poses significant environmental and public health risks, necessitating effective treatment technologies. This study investigates the degradation of three types of TCs in water—Tetracycline (TC), Oxytetracycline (OTC), and Chlortetracycline (CTC)—using nonthermal plasma (NTP) coupled with the persulfate (PS) process. The combined NTP/PS system was optimized for various operational parameters, including PS concentration, pH, and reaction time, to achieve maximum degradation and mineralization efficiency. The results showed that the NTP/PS system achieved over 90% degradation of all TCs under optimal conditions, outperforming plasma alone treatment. The degradation kinetics followed a pseudo-first-order model, indicating a rapid initial breakdown of TCs. The degradation mechanism was elucidated through the identification of intermediate byproducts using liquid chromatography-mass spectrometry (LC-MS/MS). Free radicals, such as sulfate (SO₄^•−) and hydroxyl (^•OH) radicals, were identified as the primary reactive species responsible for TCs degradation. This study demonstrates the potential of the NTP/PS system as an efficient and sustainable solution for the removal of antibiotic contaminants from water. Further research on the scalability and application in real wastewater conditions is recommended. Full article

Fenton oxidation technology utilizing hydrogen peroxide is recognized as an effective method for producing reactive oxygen species (ROS) to facilitate the degradation of antibiotics. However, the requirement for strongly acidic conditions during this process significantly restricts its broader applicability. In this study, we synthesized black phosphorus (BP) nanosheets by exposing the {010} crystal planes and then constructed a 0D/2D BP/Bi₂MoO₆ (PBMO) heterojunction to function as a Fenton catalyst. The PBMO-75 heterojunction exhibited a remarkable increase in photo-Fenton catalytic activity towards oxytetracycline (OTC) under neutral conditions, achieving catalytic efficiencies that were 20 and 8 times greater than those of BP and Bi₂MoO₆ (BMO), respectively. This can be attributed to its strong absorption of visible light, the establishment of an internal electric field (IEF) at the interface, and the implementation of a Z-scheme catalytic mechanism. Additionally, the photo-Fenton system was further improved in OTC degradation through the continuous conversion of Mo⁶⁺/Mo⁵⁺ under visible light irradiation in conjunction with H₂O₂. Based on ERS, XPS, and active species trapping experiments, we propose a Z-scheme charge transfer mechanism for PBMO. This research offers compelling evidence that 0D/2D Z-scheme heterojunctions are promising candidates for the photo-Fenton treatment of antibiotic contaminants. Full article

In this study, a Z-scheme Ho₂InSbO₇/Ag₃PO₄ (HAO) heterojunction photocatalyst was successfully fabricated for the first time by ultrasound-assisted solvothermal method. The structural features, compositional components and morphological characteristics of the synthesized materials were thoroughly characterized by a series of techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectrum, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. A comprehensive array of analytical techniques, including ultraviolet-visible diffuse reflectance absorption spectra, photoluminescence spectroscopy, time-resolved photoluminescence spectroscopy, photocurrent testing, electrochemical impedance spectroscopy, electron paramagnetic resonance, and ultraviolet photoelectron spectroscopy, was employed to systematically investigate the optical, chemical, and photoelectronic properties of the materials. Using oxytetracycline (OTC), a representative tetracycline antibiotic, as the target substrate, the photocatalytic activity of the HAO composite was assessed under visible light irradiation. Comparative analyses demonstrated that the photocatalytic degradation capability of the HAO composite surpassed those of its individual components. Notably, during the degradation process, the application of the HAO composite resulted in an impressive removal efficiency of 99.89% for OTC within a span of 95 min, along with a total organic carbon mineralization rate of 98.35%. This outstanding photocatalytic performance could be ascribed to the efficient Z-scheme electron-hole separation system occurring between Ho₂InSbO₇ and Ag₃PO₄. Moreover, the adaptability and stability of the HAO heterojunction were thoroughly validated. Through experiments involving the capture of reactive species and electron paramagnetic resonance analysis, the active species generated by HAO were identified as hydroxyl radicals (•OH), superoxide anions (•O₂⁻), and holes (h⁺). This identification provides valuable insights into the mechanisms and pathways associated with the photodegradation of OTC. In conclusion, this research not only elucidates the potential of HAO as an efficient Z-scheme heterojunction photocatalyst but also marks a significant contribution to the advancement of sustainable remediation strategies for OTC contamination. Full article

Antibiotic resistance has been recognized as a global threat to human health. Therefore, it is urgent to develop effective strategies to address the contamination of water environments caused by antibiotics. In this study, Fe/Mn bimetallic-modified biochar (FMBC) was synthesized through a one-pot oxidation/reduction-hydrothermal co-precipitation method, demonstrating an exceptional photocatalytic-Fenton degradation performance for oxytetracycline (OTC). Characterization techniques including FTIR, SEM, XRD, VSM, and N₂ adsorption–desorption analysis confirmed that the Fe/Mn bimetals were successfully loaded onto the surface of biochar in the form of Fe₃O₄ and MnFe₂O₄ mixed crystals and exhibited favorable paramagnetic properties that facilitate magnetic recovery. A key innovation is the utilization of biochar’s inherent phenol/quinone structures as reactive sites and electron transfer mediators, which synergistically interact with the loaded bimetallic oxides to significantly enhance the generation of highly reactive ·OH radicals, thereby boosting catalytic activity. Even after five recycling cycles, the material exhibited minimal changes in degradation efficiency and bimetallic crystal structure, indicating its notable stability and reusability. The photocatalytic degradation experiment conducted in a Fenton-like reaction system demonstrates that, under the conditions of pH 4.0, a H₂O₂ concentration of 5.16 mmol/L, a catalyst dosage of 0.20 g/L, and an OTC concentration of 100 mg/L, the optimal degradation efficiency of 98.3% can be achieved. Additionally, the pseudo-first-order kinetic rate constant was determined to be 4.88 min⁻¹. Furthermore, this study elucidated the detailed degradation mechanisms, pathways, and the influence of various ions, providing valuable theoretical insights and technical support for the degradation of antibiotics in real wastewater. Full article

The widespread contamination of aquatic environments by tetracycline antibiotics (TCs) poses a substantial threat to public health and ecosystem stability. Although photo-Fenton processes have demonstrated remarkable efficacy in degrading TCs, their practical application is limited by challenges associated with catalyst recyclability. This study reports the development of a novel magnetic recoverable SrFe₁₂O₁₉/g-C₃N₄ heterostructure photocatalyst synthesized via a facile one-step co-calcination method using industrial-grade precursors. Comprehensive characterization revealed that nitrogen defects and the formation of heterojunction structures significantly suppress electron (e⁻)–hole (h⁺) pair recombination, thereby markedly enhancing catalytic activity. The optimized 7-SFO/CN composite removes over 90% of oxytetracycline (OTC) within 60 min, achieving degradation rate constants of 0.0393 min⁻¹, which are 9.1 times higher than those of SrFe₁₂O₁₉ (0.0043 min⁻¹) and 4.2 times higher than those of g-C₃N₄ (0.0094 min⁻¹). The effectively separated e⁻ play three critical roles: (i) directly activating H₂O₂ to generate ·OH radicals, (ii) promoting the redox cycling of Fe²⁺/Fe³⁺ ions, and (iii) reducing dissolved oxygen to form ·O₂⁻ species. Concurrently, h⁺ directly oxidize OTC molecules through surface-mediated reactions. Furthermore, the 7-SFO/CN composite exhibits exceptional operational stability and applicability, offering a transformative approach for scalable photocatalytic water treatment systems. This work provides an effective strategy for designing efficient and recoverable photocatalysts for environmental remediation. Full article

Tetracyclines (TCs) pollution in vegetable fields is a widely recognized concern, yet the health and ecological risks of TCs residues in the soil–cabbage food chain remain unclear. This study used enzyme-linked immunosorbent assay (ELISA) to investigate the health risks associated with TCs contamination in soil–cabbage (Brassica campestris L. ssp. chinensis) systems to better understand TCs accumulation in soil–cabbage and its impact on human health. The human health risks of the edible parts of Chinese cabbage and the ecological risks of TCs-contaminated soils were assessed using the health risk quotient method (RQ) and risk quotient method, respectively. The results showed that after 65 days of tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC) treatments, the degradation rates of TCs in soil were higher in black soil than in purplish clay soil, following the order of OTC > CTC > TC. As the three types of TCs concentration increased (0–20 mg kg⁻¹), their accumulation in the leaves and roots of Chinese cabbage in purplish clay soil was generally higher than in black soil. The health risk values of the three types of TCs in Chinese cabbage were also higher in purplish clay soil than in black soil, following the order of TC > CTC > OTC. Under controlled pot experimental conditions, the TC content in Chinese cabbage grown in purplish clay soil posed moderate risks to children aged 1–6 years (0.1 < HQ < 1.0), while the CTC and OTC contents in Chinese cabbage leaves indicated low risks to both adults and children (HQ ≤ 0.1). Additionally, all three TCs in both soils posed high ecological risks (RQ ≥ 1.0), with risk values being higher in purplish clay soil than in black soil, following the order of TC > CTC > OTC. Consequently, more fertile soils can help mitigate the impact of TCs pollution on human health and ecological safety. Full article

Novel S-scheme heterojunction interface composite (MnMgPO₄@C₃N₄) of bimetallic phosphate MnMgPO₄ and C₃N₄ with different proportions was successfully constructed in this work. The nanosheet surface structure and the integration interface of two materials endowed the composite heterojunctions with superior visible light absorption and improved photogenerated carrier transfer, boosting the photocatalytic hydrogen production and degradation performance. The interface composite (5C5MMP) with the optimal mass ratio (MnMgPO₄/C₃N₄ = 5/5) achieved the strongest photocatalytic potency. The hydrogen evolution rate was about 3.595 mmol·g⁻¹·h⁻¹, and the pollutants of methylene blue (MB), oxytetracycline (OTC), and tetracycline (TE) were almost entirely degraded within 40 min. The degradation rates were approximately 97.1% (MB), 95.4% (OTC), and 99.7% (TE). Notably, the heterojunction interface composite displayed exceptional photocatalytic stability and structural durability. The photocatalytic mechanism revealed that the 5C5MMP heterojunction interface exhibited the strongest photocurrent response, the least electron transfer resistance, and the lowest carrier recombination rate, resulting in exceptional photocatalytic performance. Furthermore, both C₃N₄ and MgMnPO₄ were identified as n-type semiconductors. The optimized band structure of the composite photocatalyst interface and the enhanced charge carrier separation enabled the 5C5MMP photocatalytic system to generate more reactive photogenerated electrons for reduction and holes for oxidation, significantly accelerating the photocatalytic hydrogen production and pollutant degradation. By proposing an S-scheme heterojunction interface composite, this research offers an innovative strategy for designing efficient composite photocatalysts and underscores the feasibility of using bimetallic phosphate composites to enhance hydrogen production and pollutant removal. Full article

Improving the photogenerated carrier separation efficiency of individual semiconductor materials has always been a key challenge in photocatalysis. In this study, we synthesized a novel photocatalytic material, N-CQDs/UBWO, in situ by combining nitrogen-doped carbon quantum dots (N-CQDs) derived from discarded corn stover with ultrathin Bi₂WO₆ nanosheets (UBWO). Detailed characterization indicates that the random distribution of N-CQDs on the UBWO surface increases the specific surface area of UBWO, which is beneficial for the adsorption and degradation of oxytetracycline (OTC). More importantly, N-CQDs act as electron acceptors, promoting the effective separation of photogenerated charges, prolonging the lifetime of charge carriers in UBWO, and thereby enhancing the degradation efficiency of OTC. As a result, the optimized 3wt%N-CQDs/UBWO could degrade 85% of OTC within 40 min under visible light, with a removal rate four times that of pure Bi₂WO₆. The performance of photocatalytic degradation over OTC by 3wt%N-CQDs/UBWO exceeds that of most reported Bi₂WO₆-based photocatalysts. The EPR analysis confirmed that ∙O₂⁻ and ∙OH are the main active species in the photocatalytic degradation of OTC on 3wt%N-CQDs/UBWO. This study provides insight into designing green, low-cost, and efficient photocatalysts using CQDs derived from waste biomass and the degradation of emerging pollutants like antibiotics. Full article

Water quality is threatened by numerous pollutants, among which antibiotics are of great concern due to their widespread use and unaltered excretion, leading to water contamination and fostering antibiotic resistance. To comprehensively address sustainable water remediation, herein, the susceptibility to non-thermal plasma degradation of two veterinary antibiotics (Oxytetracycline (OTC) and Lincomycin (LNC)) are compared in an integral approach, including computational analyses, plasma irradiation assays, and a byproduct toxicity assessment. The computational assessment was performed by evaluating the ionization potential (IP) obtained from Density Functional Theory calculations and determining the antibiotics’ susceptible sites for radical attack. Plasma irradiation achieved nearly complete degradation (~100%) of both compounds with the initial concentration of 1 mg L⁻¹, while 60% degradation was observed when the starting concentration was 10 mg L⁻¹. The mineralization rates were 21% and 31% for OTC and LNC, respectively. The degradation profiles followed similar trends, as expected from their comparable IP values. After treatment, the solution exhibited lower biotoxicity compared to the original antibiotics. Therefore, this work represents a step forward in addressing one of the key environmental challenges of our time and encourages further extending the analysis towards the remediation of water polluted with many other organic compounds. Full article