Tetracycline Research Articles

CoFe2O4/carbon nitride Z-scheme heterojunction photocatalytic PMS activation for efficient tetracycline degradation: Accelerated electron transfer

The escalating consumption of antibiotics and their subsequent discharge into the water supply is a matter of significant concern. This study presents an innovative visible light (VL) activated peroxymonosulfate (PMS) system for efficient degradation of the targeted antibiotic tetracycline (TC). CoFe2O4/carbon nitride (CFO/CN) Z-scheme heterojunctions were designed and synthesized through a simple co-precipitation and calcination strategy. Surface and analytical techniques were employed to comprehensively characterize the prepared CFO/CN, demonstrating its enhanced efficiency in separating photoinduced charge carriers. CFO/CN exhibited a 27-fold enhancement in TC degradation rate constants with PMS under VL. The effects of various factors including catalyst dosage, PMS concentration, initial pH, and content of CFO on TC degradation efficiency were investigated. Reactive species quenching and EPR measurements revealed the main contribution of superoxide radicals (•O2−) made to TC degradation. TC degradation pathways were proposed based on oxidized product analysis. The assessment of acute toxicity demonstrated the reduced toxicity of the formed intermediates. A plausible mechanism for TC degradation over CFO/CN-PMS-VL was discussed. This work provides a comprehensive guide for heterojunction photocatalytic activation of PMS for efficient micropollutant degradation.

Engineered biochar for advanced oxidation process towards tetracycline degradation: Role of iron and graphitic structure

The excessive accumulation of tetracycline (TC) presents significant challenges to both human health and the ecological environment. This study explores the impact of Fe-loaded sawdust graphitic carbon (engineered biochar) on TC degradation in water, utilizing an advanced oxidation process facilitated by H2O2 activation. The investigation encompasses an examination of the structural characteristics of Fe-loaded sawdust graphitic carbon and an in-depth analysis of its catalytic degradation mechanism concerning TC. Density functional theory (DFT) was utilized to construct an adsorptive degradation system for TC in water, thereby scrutinizing the optimal treatment process for TC. The findings highlight that Fe-loaded biochar exhibits not only a substantial pore structure but also inherent defects and a graphitic structure. The porous configuration enhances the TC adsorption capacity of the biochar system, while the graphitic structure bolsters the stability of the carbon framework, ensuring efficient charge transfer via the carbon defects. The activation effect of Fe(III) on H2O2 into ·O2- is dependent on its specific location within the carbon structure. In the presence of 5 mmol H2O2, Fe-loaded biochar achieves a nearly 100 % degradation rate of TC, with its degradation proficiency minimally influenced by varying pH conditions.

A novel 0D/3D Z-Scheme heterojunction ZnS/MIL-88(A) with significantly boosted photocatalytic activity toward tetracycline

Coupling two different photocatalytic materials to construct a heterojunction is a preferable strategy for obtaining the composite photocatalyst with high activity. Herein, a novel 0D/3D Z-scheme heterostructure ZnS/MIL-88(A) was constructed by anchoring 0D ZnS nanoparticles on the surface of the 3D MIL-88(A). The prepared ZnS/MIL-88(A) was characterized by using FT-IR, XRD, SEM, UV–vis and XPS. The photodegradation of tetracycline (TC) was conducted under the irradiation of visible light to evaluate the photocatalytic performance of ZnS/MIL-88(A). The creation of the Z-scheme heterostructure between ZnS and MIL-88(A) enables ZnS/MIL-88(A) to exhibit excellent visible-light absorption ability and dramatically boost separation and transfer of the photo-induced charge carriers. Compared with MIL-88(A), ZnS/MIL-88(A) shows prominently enhanced photocatalytic activity toward tetracycline, achieving a TC degradation rate of 94 %. The highest photodegradation rate constant (0.02083 min−1) of TC by ZnS/MIL-88(A) is 7.77 and 12.33 folds as large as those by MIL-88(A) and ZnS, respectively. After five cycles of reuse, ZnS/MIL-88(A) shows only a slightly decreased TC removal rate, presenting excellent photo-stability. Furthermore, the Z-scheme interfacial charge migration mode and the photocatalytic mechanism of ZnS/MIL-88(A) were discussed according to the band position as well as the identification result of the active species. The radicals ·O2− and ·OH generated in photocatalysis serve as major reactive species to decompose TC. This work provides a new way for designing efficient composite photocatalysts.

Persistent luminescent ZnAl-LDH nanosheets for all-weather degradation of nitenpyram and tetracycline: Superoxide radical induction, life cycle analysis and engineering applications

Photocatalysts designed for all-weather applications, capable of efficient charge carrier separation, are set to transform the adoption of photocatalysis-driven advanced oxidation processes in wastewater management. In this investigation, an energy-storing ZnAl-LDH@SrAl2O4:Eu2+, Dy3+ (SALDH) was synthesized successfully, optimized for the photocatalytic selective degradation of NTP and tetracycline hydrochloride (TC) under varying weather conditions, with 100 % degradation of both NTP and TC within 75 min. Remarkably, SALDH demonstrates energy storage capabilities that markedly reduce energy demands relative to traditional photocatalytic approaches. The primary reactive species identified were O2−, and the Fukui index, computed via density-functional theory (DFT), identified the specific interaction sites of O2− on NTP molecules. Utilizing the energy retention properties of SALDH, a novel, environmentally friendly device was engineered for processing organic pollutants in agricultural wastewater. This system harness the energy from solar radiation to induce the oxidation of pollutants. The experiments that were performed in the both artificially prepared lab-scale and actual agricultural WWT plants indicated the degradation efficiencies of 36 % and 37 %, respectively. As seen during the day, both SALDH and persulfate were capable of effectively decomposing organic contaminants; at night, the SA’s luminescence maintained the oxidative ability of ZnAl-LDH. Meanwhile, SALDH combines the corrosion resistance of ZnAl-LDH with good metal compatibility, enabling SALDH to effectively improve the photostability of long afterglow. This work contributes to the existing knowledge on the degradation of organic pollutants by efficient photocatalysts and points to possible implementations in water treatment processes.

Biosurfactant-mediated transport of tetracycline antibiotics in saturated porous media: Combined effects of the chemical properties of contaminants and solution chemistry conditions

The mobility of tetracycline antibiotics (TCs) in saturated aquifers is possibly affected by the presence of biosurfactants, which are widespread in the aquatic/soil environments. This study investigated the mobility characteristics of various tetracyclines—specifically tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC)—within quartz sand columns in the presence of rhamnolipid, a common biosurfactant. Exogenous rhamnolipid significantly inhibited the transport of the three TCs over the pH range of 5.0–9.0 (e.g., the mass of retained TC, OTC, and CTC increased from 32.6 %, 26.9 %, and 39.2 % (in the absence rhamnolipid) to 39.4 %, 38.9 %, and 51.7 % (in the presence of rhamnolipid), respectively). This observation could be attributed to the bridging effects of this biosurfactant. Specifically, the hydrophilic head of rhamnolipid molecules is likely associated with the surfaces of sand grains through surface complexation and/or hydrogen bonding interactions. Accordingly, the hydrophobic moieties of the deposited rhamnolipid molecules (i.e., the aliphatic chains) interact with the hydrophobic groups of TCs molecules via hydrophobic interactions. Interestingly, the extent of the inhibitory effect on CTC mobility was greater than that on OTC and TC, which was related to the different hydrophobic characteristics of the three antibiotics. Furthermore, the inhibitory effect of rhamnolipid on the transport of TCs diminished as the pH of the background solution increased. This observation was attributed to the weakened bridging effects, resulting from the reduced deposition of the biosurfactant on the sand surfaces. Additionally, the cation-bridging mechanism involved in the retention of TCs in the addition of rhamnolipid when the background electrolyte was Ca2+ (i.e., Ca2+ ions served as bridging agents between the deposited rhamnolipid molecules and TCs). The insightful findings enhance our understanding of the critical roles of biosurfactants in influencing the environmental dynamics and ultimate fate of conventional antibiotic pollutants within groundwater systems.

A high-efficiency and selective fluorescent assay for the detection of tetracyclines

Tetracyclines (TCs) rank second globally in the use of animal infection therapy and animal husbandry as growth promoters among all antibiotics. However, large amounts of TCs residue in food products and more than 75% of TCs are excreted into the environment, causing adverse effects on the ecological system and human health. It has been challenging to simultaneously realize low-cost, rapid, and highly selective detection of TCs. Here, inspired by the fluorogenic reactions between resorcinol and catecholamines, we find the fluorescence quenching ability of tetracycline (TC) and firstly propose a fluorescent “turn-off” detection of TC using dopamine and 4-fluororesorcinol. The optimal reaction condition for the fluorescent assay is investigated and the optimized probe showed a good limit of detection (LOD of 1.7 µM) and a wide linear range (10 µM to 350 µM). Moreover, this fluorescent assay proved to be an effective tool for detecting TC in river, Sprite, and beer samples, which represent the aquatic environments and food and may contain tetracyclines residues. Finally, the high selectivity of the method for TC has been confirmed by eliminating the interference from common substances. The proposed strategy provides a high-efficiency and selective solution for the detection of TCs in environment and food and the application fields of this fluorescent assay could be further expanded in the future.

Synthesis of a novel flower-like Bi4Ti3O12/AgI Z-type heterojunction for efficient photocatalytic removal of tetracycline antibiotic and RhB

Novel Flowerlike Bi4Ti3O12/AgI (BTO/AgI) Z-type heterojunctions were fabricated via a straightforward in-situ precipitation method. Notably, BTO/AgI exhibited significantly improved photodegradation efficiency for tetracycline (TC) and Rhodamine B (RhB). The rate constants for RhB and TC photodegradation were approximately 20.8 and 2.9 times higher than those of BTO alone, respectively. Furthermore, the photocatalytic efficiency of the BTO/AgI heterojunction is 1.4 times higher than that of the mixture of the two individual photocatalysts, indicating a robust interaction between BTO and AgI. This enhancement in photocatalytic performance was mainly attributed to the effective separation of photogenerated carriers facilitated by the Z-scheme heterojunction, which can be demonstrated by the highest photocurrent density (∼0.307 μA·cm−2) of BTO/AgI, surpassing BTO (∼0.073 μA·cm−2) and AgI (∼0.161 μA·cm−2) by approximately 4.12 and 1.91 times, respectively. Furthermore, three plausible photodegradation pathways of tetracycline were proposed. This study introduces a novel approach for designing and synthesizing high-efficiency Z-scheme photocatalysts for the degradation of TC and RhB in wastewater.

Treatment of Macrolide-resistant Mycoplasma pneumoniae Pneumonia in Children: A Meta-analysis of Macrolides Versus Tetracyclines.

The global prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) pneumonia infections, particularly in children, is on the rise. It is imperative to assess the clinical efficacies of alternative antibiotics such as tetracyclines to ensure effective treatment, mitigate antibiotic resistance, enhance clinical outcomes, and minimize the spread of resistant strains among MRMP-infected children. The objective of this study was to compare the therapeutic efficacies of macrolides and tetracyclines in treating MRMP pneumonia in children. We systematically searched the literature to identify comparative studies that examined the clinical outcomes of macrolide and tetracycline antibiotics in children with MRMP pneumonia. We conducted a meta-analysis of the mean duration of fever, hospital stay duration, therapeutic efficacies, and time to defervescence to compare macrolides and tetracyclines. Eleven studies involving 1143 patients compared the clinical efficacies of macrolides and tetracyclines in children with MRMP pneumonia. The studies were conducted in China, Japan, and Korea, and the outcomes of febrile days, hospital stay duration, therapeutic efficacy, and time to defervescence were analyzed. The macrolides studied were azithromycin and clarithromycin, whereas the tetracyclines included minocycline and doxycycline. The pooled estimate of 5 studies showed that the mean duration of febrile days and hospital stay was longer in the macrolides group than tetracycline group [weighted mean difference = 1.64 days, 95% confidence interval (CI): 0.68-2.59, weighted mean difference = 1.22 days, 95% CI: 0.82-1.62, respectively]. The therapeutic efficacy was significantly lower in the macrolide group than in the tetracycline group (odds ratio: 0.33, 95% CI: 0.20-0.57). The clinical efficacy of tetracycline treatment was superior to that of macrolide treatment in children with MRMP pneumonia. However, further research is required to validate these findings and inform evidence-based clinical practice guidelines.

Excellent antibiotic degradation through PMS activation via bio derived Fe-Mn oxides with tunable defect concentration: Synergy between singlet oxygen oxidation and electron transfer

Regulating the defect sites and structural composition of metal-based metal catalysts is an effective strategy to improve the activity of activating PMS to degrade pollutants. Herein, bio derived Fe/Mn composite oxides (BFMO) rich in oxygen vacancy composed of crystalline manganese oxide coated with amorphous iron oxide was prepared through microbial mediation, and used for PMS activation in the degradation of tetracycline (TC). After 60 minutes reaction, the removal rate of TC achieved 92.4 %−98.8 % within wide pH range of 3–12. Besides, this system has outstanding anti-interference ability to common ions and humic acid (HA). The outstanding catalytic performance stemmed from the non-radical pathway for producing singlet oxygen (1O2) and electron transfer, facilitated by defect-rich polyvalent Mn and amorphous Fe species. Polyvalent Mn species accelerate the electron transfer process, and its surface defect structure further promotes the adsorption of pollutants on the surface of the materials. The redox cycle of Fe3+/Fe2+ was accelerate via electron-rich groups. This study explored the synergy triggered by microbe-mediated defect sites and structure-dependent, providing a design strategy for environmental remediation of PMS activated by Fe/Mn based bimetallic catalysts with strong resistance to environmental interference.

Oxygen Vacancies Regulated S-Scheme Charge Transport Route in BiVO4-OVs/g-C3N4 Heterojunction for Enhanced Photocatalytic Performance.

Oxygen vacancies (OVs) are widely considered as active sites in photocatalytic reactions, yet the crucial role of OVs in S-scheme heterojunction photocatalysts requires deeper understanding. In this work, OVs at hetero-interface regulated S-scheme BiVO4-OVs/g-C3N4 photocatalysts are constructed. The Fermi-level structures of BiVO4 and g-C3N4 lead to a redistribution of charges at the heterojunction interface, inducing an internal electric field at the interface, which tends to promote the recombination of photogenerated carriers at the interface. Importantly, the introduction of OVs induces defect electronic states in the BiVO4 bandgap, creating indirect recombination energy level that serves as crucial intermediator for photogenerated carrier recombination in the S-scheme heterojunction. As a result, the photocatalytic degradation rate on Rhodamine B (RhB) and tetracyclines (TCs) for the optimal sample is 10.7 and 11.8 times higher than the bare one, the photocatalytic hydrogen production rate is also improved to 558 µmol g-1 h-1. This work shows the importance of OVs in heterostructure photocatalysis from both thermodynamic and kinetic aspects and may provide new insight into the rational design of S-scheme photocatalysts.

The impairment of joint tetracycline and copper oxide nanoparticle exposure on activated sludge

The increasing usage of two emerging contaminants (i.e., tetracycline (TET) and copper oxide nanoparticles (CuO-NPs)) has raised wide concerns about their potential impacts on the efficiency of wastewater treatment. However, the joint effects of TET and CuO-NPs on activated sludge processes have rarely been documented. This study investigated the sludge characteristics and bioactivities under both individual and joint exposure to TET (1 mg/L) and CuO-NPs (2 mg/L) for 60 days. The results demonstrated that both individual and joint exposures of TET and CuO-NPs deteriorated the flocculation ability and dewatering of sludge by inducing non-filamentous bacteria. The joint exposure showed higher effects on sludge when compared with individual exposure. Sludge characterization analysis attributed this deterioration partly to the increased extracellular polymeric substance (EPS) secretion (especially loose-bound EPS). In addition, exposure to CuO-NPs would result in an inhibition of total nitrogen removal due to impairment of the denitrification process (i.e., nitrate reductase, nitrous reductase, and electron-transfer associated enzyme), but not for TET. The inhibition of nitrogen removal could be exacerbated when simultaneously exposed to CuO-NPs and TET. 16S rRNA analysis further revealed that the long-term joint exposure to TET and CuO-NPs resulted in a significant decrease in microbial community richness, diversity, and associated functional bacteria abundance. The results of this study suggest that joint exposure to TET and CuO-NPs results in the deterioration of sludge function efficiency.

A novel barium zirconate titanate/Fe-MOF nanocomposite: Synthesis, characterization, and photocatalytic mechanism

The synthesis of a metal-organic framework (MOF) matrix of MIL-100 (Fe) loaded with BaTi0.85Zr0.15O3 (BTZ) nanoparticles (NPs) was achieved by an easy one-pot solvothermal procedure and encasing of BTZ NPs. X-ray diffraction (XRD), photoluminescence spectroscopy (PL), UV-Vis reflectance spectroscopy (DRS), Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and N2 adsorption-desorption were deployed for the characterization of the synthesized samples. The degradation efficiency for tetracycline (TC), among the photocatalytic BTZ/MIL-100(Fe) nanocomposites with varied BTZ percentages (10, 20, 30, and 40 wt% BTZ), revealed that (30 wt%), offered the best outcome. At 0.8 g L-1 of the catalyst, pH 9, 30 ppm TC solution, and 180 min irradiation time, as the optimal conditions, the degradation efficiency of TC molecules reached >90. Based on the study of some scavenging agents, the importance of the reactive species in TC photodegradation followed the trend of photogenerated e-, hydroxyl radicals, superoxide radicals, and photogenerated h+. TC degradation occurred through reduction and oxidation pathways via a direct Z-scheme mechanism. This work aims to describe the use of MOF-based materials as a visible-light-driven photocatalyst towards TC.

Optimization of Ecofriendly L-Fe/Ni Nanoparticles prepared using extract of black tea leaves for Removal of tetracycline antibiotics from Groundwater by Response Surface Methodology

This article focuses on employment of nanotechnologies in remediation of tetracycline antibiotics (TC) from groundwater by green synthesized bimetallic Fe/Ni supported by limestone particles. An in-situ green synthesis nanoparticles was prepared using black tea leaves extract to generate a L-Fe/Ni nanocomposite. The synthesized nanocomposite was characterized using several techniques, such as, X-Ray Diffraction (XRD), Scanning Electron microscopy (SEM), transmission electron microscope (TEM), Energy dispersive X-ray (EDX), FTIR (Fourier Transform-Infra Red) spectroscopy and surface area. We then use response surface methodology (RSM) to optimize the synthesis process and evaluate the effectiveness of the prepared nanocomposite for tetracycline remediation. We took different simulated concentrations of the TC contaminant without relying on actual TC concentrations in grounwater, the best removal of the TC contaminant in batch study was investigated with relying on the initial concentrations of TC and other experimental factors such as pH, adsorbent nanomaterial concentration and time. A pilot plant was then constructed to eliminate the TC contaminant from groundwater in different concentrations, where the removal efficiency was found decreased with increasing in the concentration of the TC Many parameters affecting the removal mechanisms in statistical and continuous systems were examined to select the best results that accomplish the maximum elimination rate. With the improved operating conditions, (L-Fe/Ni concentration: 1500 mg/L; concentration of TC: 20 mg/L; pH: 7.2; contact time: 128 min), removal percent of TC was found 87 % based on RSM system. The L-Fe/Ni reactive medium of continuous column has a main role in slowing down the movement of the TC plume. This study showed that the ecofriendly nanocomposite could be an appropriate and novel method for remediation of antibiotics and other contaminants in groundwater.

Zero-valent iron on graphite-cellulose biochar catalysts for the Fenton degradation of tetracycline from water

Tetracycline (TC), an antibiotic widely used in the treatment of animal and human diseases and promotion of animal growth. However, its uncontrolled discharge to water sources can also cause the promotion of antibiotic resistant bacteria and genes. In this study, graphite and cellulose were used as raw materials to construct a graphite-biochar (G-BC) by carbothermal reactions. This graphite-biochar was subsequently mixed with ZVI with various mass ratios by ball milling to produce graphite-biochars supported ZVI (ZVI/G-BC) catalysts, further used in the heterogeneous Fenton degradation of tetracycline. The materials were fully characterized by different techniques. The removal of TC by BC, G-BC and ZVI/G-BC was tested under different reaction conditions. The best synthesis conditions were achieved at a heating temperature of 700 °C, a graphite content of 20 %, a ball milling speed of 500 rpm, a ball milling time of 5 h, as well as a G-BC and ZVI mass ratio of 1:3. Graphite improves the conductivity and micropore area of the material, which enhances the removal of TC by ZVI/G-BC catalysts in Fenton-like reactions. TC was first oxidized to intermediate products and then further mineralized to CO2 and H2O. The best TC removal performance was obtained with a catalyst dosage of 1.1 g·L1, a hydrogen peroxide concentration of 140 mM and an initial pH value of 3. The reaction data fitted properly a pseudo first-order kinetic equation. TC removal as high as 91 % was achieved even in the 3rd round of reuse. This study reports a novel ZVI material with high conductivity and good TC removal performance.

Preparation of novel semi-covalent molecularly imprinted polymer for highly improved adsorption performance of tetracycline in aqueous medium

In the present study, a novel tetracycline-imprinted polymer for tetracycline (TC) adsorption in an aqueous medium was synthesized using a semi-covalent imprinting method for the first time. In this approach, the template-monomer complex was synthesized by the reaction of 3-isopropenyl-α,α-dimethylbenzyl isocyanate (IPDMBI) as the functional monomer and TC as a template, forming a thermally reversible urethane bond (covalent bond). The polymer was characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), nitrogen adsorption/desorption measurements, and determination of point zero charge (PCZ). The equilibrium time of TC onto MIP was reached in 15 min, which was described by the non-linear pseud second-order kinetic model. Adsorption isotherm was described as a dual-site Langmuir-Freundlich model and the maximum adsorption capacity, determined at pH 5.0, was found to be 76.74 mg g−1 for MIP, exhibiting higher adsorption capacity when compared with other adsorbent materials previously reported in the literature for TC. Based on the increment relative selectivity coefficient the MIP showed higher selectivity towards TC and some structurally similar compounds belonging to the tetracyclines family (oxytetracycline and chlorotetracycline), when compared with NIP (non-imprinted polymer). The obtained outcomes in terms of selectivity, maximum adsorption capacity, and fast kinetic make this imprinted polymer an outstanding material for future application in molecularly imprinted solid phase extraction for analytical purposes.

Nanozyme-Based Colorimetric and Smartphone Imaging Advanced Sensing Platforms for Tetracycline Detection and Removal in Food

The presence of antibiotic residues poses a significant threat to food assurance, triggering widespread concerns. Therefore, the prompt and accurate detection and removal of antibiotic residues are essential for ensuring food safety. In this study, an aptmer modified triple-metal nanozyme (apt-TMNzyme) sensor was developed, which achieved a portable, visual, intelligent, and fast determination for tetracycline (TET). The proposed apt-TMNzyme exhibited willow leaf-like morphology, high specific surface area and excellent TET adsorption and removal properties. The experiments showed that the apt-TMNzyme had outstanding peroxidase activity and could catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue product in the presence of H2O2, which provided a visual response signal to TET. This sensor was capable of quantifying TET within a concentration range of 0.2 nM-70 μM, achieving a detection limit of 7.1 nM under optimal conditions. When tested on real food samples, our sensor produced results that closely paralleled those achieved through high-performance liquid chromatography. To improve accessibility and user-friendliness, we also designed a colorimetric testing paper integrated with a smartphone application for intuitive and intelligent detection of TET, which enables the quantitative determination of TET in the concentration range of 0.003-60 μM, the detection limit was 5.1 μM. This integrated portable sensor not only streamlines the testing process, saving time and costs, but also offers a promising solution for rapid and sensitive detection of antibiotic residues.

Fabrication of ratiometric molecular imprinting electrochemiluminescence sensor based on polyethyleneimine hydrogel loading layered bimetallic hydroxide and MIL-125@Ru(bpy)32+ for sensitive tetracycline detection

In this work, layered Co-Ni bimetallic hydroxide was synthesized and combined with polyethyleneimine hydrogel (PEI@LDH) as substrate material, then the metal-organic framework MIL-125 loaded Ru(bpy)32+ (MIL@Ru) was added as single luminophore, followed by electrochemical deposition of tetracycline (TC) imprinted copolymer of hydroquinone and o-phenylenediamine to construct an electrochemiluminescent (ECL) sensor for TC detection. The stable and sensitive luminophore MIL@Ru associating with co-reactant K2S2O8 in the solution could cause a cathode ECL signal sensing TC, it could also associate with the immobilized co-reactant PEI hydrogel to produce a stable anode ECL signal acting as a reference. The LDH had catalysis and could efficiently amplify both anode and cathode ECL signals. Therefore, the constructed single luminophore based ratiometric ECL sensor displayed high selectivity, sensitivity and reproducibility. Under the selected testing conditions, the linear response range was 0.01 μmol L−1 to 1 mmol L−1 and the detection limit reached 8 nmol L−1. Its good practicability was validated by determining TC in different actual samples. Hence, the ratiometric MIP-ECL sensor was quite promising.

Effects of coexisting nanomaterials on the photodegradation behavior and ecotoxicity of antibiotics in the aqueous

Nanomaterials (NPs) and antibiotics, as two emergent pollutants, forms a complex contamination through their interaction, potentially causing adverse effects on the organism. This study systematically examined the influence of two NPs (CuO NPs and carbon nanotubes, CNTs) on the photodegradation behavior of tetracycline (TC) and their combined toxic effects on Chlorella vulgaris. The results showed that CuO NPs significantly accelerated TC photodegradation compared to CNTs, increasing the TC photodegradation rate constant by187.6%. Electron spin resonance (ESR) indicated that under the coexistence of CuO NPs or CNTs, 1O2、O2•- and •OH were the main active species promoting TC photodegradation. Probe and quenching experiments confirmed the predominant role of O2•- and 1O2 in the presence of CuO NPs and CNTs. Additionally, three possible TC photodegradation pathways were proposed for the coexistence of CuO NPs and CNTs. In the Chlorella vulgaris growth inhibition experiment, the combined toxicity of CuO NPs or CNTs and TC was higher than that of individual substance, indicating significant synergistic effects, especially with the combination of CNTs and TC. This study provides a new perspective on accurately assessing the environmental behaviors and risks when NPs and antibiotics coexist.

Enhanced adsorption-photodegradation of tetracycline using Ce-N-co-doped AC/TiO2 photocatalyst: isotherms, kinetics, mechanism, and thermodynamic insight.

Excessive use of tetracycline (TC) is alarming owing to its increased detection in water systems. In this study, a photocatalyst was developed to degrade TC using a Ce-N-co-doped AC/TiO2 photocatalyst, denoted as Ce/N-AC/TiO2, prepared using the sol-gel method assisted by microwave radiation, speeding up the synthesis process. Ce/N-AC/TiO2 achieved maximum TC degradation of 93.1% under UV light with optimum sorption system conditions of an initial concentration of 10 mg L-1, pH 7, and 30 ℃, under 120 min. Scavenger experiments revealed that holes and superoxide radicals were the active species influencing the photodegradation process.The TC degradation was appropriately fitted with Langmuir isotherms and a pseudo-second-order (PSO) kinetic model. The change in enthalpy (ΔH) (2.43kJmol-1), entropy (ΔS) (0.024kJmol-1), and Gibbs free energy (ΔG) (- 4.941 to - 5.802kJmol-1) suggested that the adsorption process was spontaneous, favourable, and endothermic. Electrostatic interaction, hydrogen bonding, pore-filling, cationic-π, n-π, and π-π interaction were among the interactions involved between TC and Ce/N-AC/TiO2. Furthermore, Ce/N-AC/TiO2 stability was confirmed through 80% removal efficiency even after the fifth reuse cycle. Notably, this work provides new insight into the production of efficient, reusable, and enhanced photocatalysts using a rapid and cost-effective microwave-assisted synthesis process for pollutant remediation.

SbSeI for high-efficient photocatalytic degradation of multiple pollutants

Photocatalytic degradation is an effective technology for degrading water pollution that plays a significant role in environmental remediation. Ternary 2D ternary V-VI-VIIA semiconductors are ideal candidates for photocatalytic degradation of pollutants due to effective light absorption and high charge carrier mobility. In this work, high-quality SbSeI crystals were prepared using the chemical vapor transport (CVT) method and their photocatalytic degradation performance for multiple pollutants was studied. SbSeI exhibits excellent photocatalytic performance in the degradation of potassium dichromate (Cr (VI)), rhodamine B (RhB), tetracycline hydrochloride (TC-HCl) and methyl orange (MO). More than 98% of Cr (VI) and RhB can be removed after irradiation with an Xe lamp for 10 min and 40 min, respectively. The capture experiments and electron spin resonance results indicated that ·O2− plays a major role in reducing Cr (VI), while h+ plays a primary role in the degradation of MO, RhB and TC-HCl. Interestingly, the degradation rate of Cr (VI) is 1.3 times higher than that of a single pollutant system, and the degradation rate of RhB is 1.6 times higher, due to the enhanced separation and utilization of holes and electrons. The results demonstrate that SbSeI is a potential photocatalytic degradation material.