Antibiotics In Aqueous Solution Research Articles

Constructing a plasmonic p-n heterojunction photocatalyst of 3D Ag/Ag6Si2O7/Bi2MoO6 for efficiently removing broad-spectrum antibiotics

The extensive production and consumption of pharmaceutical antibiotics are bringing serious environmental issues. Photocatalytic reaction has been emerging as an environment-friendly and effectively means for treating virous pollutants. Herein, we developed an effective photocatalytic system involving a novel plasmonic p-n heterojunction catalyst of Ag/Ag6Si2O7/Bi2MoO6 to efficiently eliminate environmental pharmaceutical pollutants, where the catalyst was synthesized via the in-situ growth of Ag/p-Ag6Si2O7 nanoparticles on n-Bi2MoO6 microspheres during a controlled precipitation-photoreduction process. As we predicted, the optimized plasmonic p-n heterojunction of Ag/Ag6Si2O7/Bi2MoO6 (AASO/BMO-3) shows a remarkable improved photocatalytic performance in eliminating ciprofloxacin (CIP) and tetracycline hydrochloride (TC). The reasons behind this fact is (1) the formation of p-n heterojunction between Ag6Si2O7 and Bi2MoO6 and (2) the precipitation of Ag nanoparticles with a plasmonic effect on Ag6Si2O7/Bi2MoO6, which made Ag/Ag6Si2O7/Bi2MoO6 possess a better capacity to efficiently separate the photogenerated carriers and utilize the visible-light. Moreover, superoxide free radicals (O2–) and photo-excited holes (h+) were determined to be the main active species in degrading antibiotics by the results of quenching and ESR tests. In addition, relevant experiment results indicated that the direct contact between AASO/BMO-3 and antibiotics also played an important role in the efficient elimination of antibiotics. This work gives a new plasmonic p-n heterojunction of Ag/Ag6Si2O7/Bi2MoO6 with an effective degradation and mineralization ability towards broad-spectrum antibiotics in aqueous solutions, further enriching the possibility of applying photocatalytic technology to treat wastewater containing pharmaceutical antibiotics.

Highly selective, sensitive and stable three-dimensional luminescent metal–organic framework for detecting and removing of the antibiotic in aqueous solution

An efficiently selective sensor for aquatic antibiotic detection based on a photoluminescent cadmium metal–organic framework (Cd-MOF) is researched in this work. The novel and simple luminescent MOF that composed from a π-electron rich ligand bip (3,5-bis(1-imidazol) pyridine) and H3L (2-nitro-5-(4-carboxy-2-nitrophenoxy) isophthalic) was synthesized in hydrothermal condition and characterized. Single crystal X-ray diffraction analysis demonstrated that it had an uncommon 2-nodal (3,6)-connected 3D framework with a (32·4)(34·46·53·62) topology, which could be formulated as [{[Cd2(HL)2(bip)2]·H2O}n]. Benefiting from its unique framework, [{[Cd2(HL)2(bip)2]·H2O}n] can not only respond to the trace quantity of chloramphenicol (CHL) via fluorescence quenching but also show good adsorption capability toward CHL in aqueous solution. The selective response to CHL reached up to the ppb level with high anti-interference ability in aqueous phase, and the effective detection of antibiotics had been theorized by Density Functional Theory (DFT) calculation for energy bands of H3L and antibiotics, which revealed that the cooperation influence on photo-induced electron transfer (PET) process and fluorescence inner filter effect (IFE) made CHL show more sensitive luminescence responses than other experimental antibiotics. Moreover, because of its specific interactions with analytes and relatively high porosity, the pre-enrichment makes the antibiotic fuller contact and interact with the framework, which improves the overall sensing efficiency towards CHL appreciably. Stemming from the abuse, antibiotics have been considered as the great threat to the health of human race and the sustainable development of society. Therefore, it is extremely important to achieve new technology to detect and absorb antibiotics residues in water. This work proves that metal–organic framework complexes can conform the performance of detecting and removing antibiotic in aqueous environment, that emphasizes the application of luminescent MOFs in contaminant monitoring and removing.

Synergic removal of tetracycline using hydrophilic three-dimensional nitrogen-doped porous carbon embedded with copper oxide nanoparticles by coupling adsorption and photocatalytic oxidation processes

Adsorption and photocatalytic oxidation are promising technologies for eliminating antibiotics (e.g. tetracycline) in aquatic environments. However, traditional powdery nanomaterials are limited by drawbacks of difficult separation and lack of synergistic function, which do not conform to the practical demand. Herein, we developed a simple one-step gelation-pyrolysis route to fabricate hydrophilic three-dimensional (3D) porous photocatalytic adsorbent, in which CuO nanoparticles are uniformly and firmly embedded in nitrogen-doped (N-doped) porous carbon frameworks. The obtained N-doped carbon/CuO bulky composites exhibited excellent ability to adsorb tetracycline hydrochloride (TC), which was subsequently photo-oxidized under visible light. Their hydrophilic nature favors the adsorption processes toward TC, with a maximum adsorption capacity reaching 25.03 mg∙g−1. In addition, >94.4% of TC molecules could be photo-degraded in 4 h with good cycling efficiency after three consecutive tests. Finally, a reaction scheme for removal process of TC was proposed. The obtained 3D porous N-doped carbon/CuO nanocomposites show great promise for efficient removal of antibiotics in aqueous solution by synergistically utilizing adsorption and photocatalytic oxidation processes.

Highly water-stable Cd-MOF/Tb3+ ultrathin fluorescence nanosheets for ultrasensitive and selective detection of Cefixime

Two-dimensional Cd-MOF/Tb3+ (Cd-MOF = [Cd (μ-2,3-pdc) (H2O)3]n (2,3-pdc = 2,3-pyridine dicarboxylic acid)) fluorescent nanosheets with the thickness of 1.4 nm were successfully synthesized by a simple solution route with subsequent ultrasonic exfoliation at room temperature. It was found that as-obtained Cd-MOF/Tb3+ ultrathin nanosheets could be homogeneously dispersed in aqueous system to form a sol with excellent stability. Also, the fluorescence intensity of nanosheets remarkably increased to almost 12 times higher than that of Cd-MOF/Tb3+ microsheets before exfoliation. Further investigations uncovered that the above strong fluorescence of Cd-MOF/Tb3+ nanosheets could be highly sensitively quenched by Cefixime antibiotic in aqueous solution without interference from other antibiotics, amino acids and pesticides. Hence, the as-obtained ultrathin Cd-MOF/Tb3+ nanosheets could be prepared as a highly selective and sensitive fluorescence probe for the detection of Cefixime in aqueous system. Compared with the bulk Cd-MOF/Tb3+ sensor, the Cd-MOF/Tb3+ ultrathin nanosheets sensor exhibited a far lower detection limit down to 26.7 nM for CFX. Also, the as-obtained nanosheets sensor presented satisfactory recovery ranging from 98.07% to 103.01% and acceptable repeatability (RSD < 6.29%, n = 6) for the detection of CFX in domestic water. Furthermore, the sensing mechanism studies revealed that the high selection of the present fluorescent probe for detection of CFX should be attributed to the cooperation of the photoinduced electron transfer and the inner filter effect.

Effect of surface area and physical–chemical properties of graphite and graphene-based materials on their adsorption capacity towards metronidazole and trimethoprim antibiotics in aqueous solution

The adsorption of metronidazole (MNZ) and trimethoprim (TMP) antibiotics from water on nanomaterials synthesized from graphene oxide and graphite, was examined thoroughly. The effect of the physicochemical properties and surface area onto the adsorption capacity of the nanomaterials was studied in detail. The nanocarbon materials used were graphene oxide (GO), and GO reduced in inert medium (rGO) or ammonia (N-rGO), and four high surface area graphites (HSAG100, HSAG300, HSAG400, HSAG500). The nanomaterials characterization was performed by transmission and scanning electron microscopy, N2 physisorption, TG-profiles and X-ray diffraction. The increasing order of the nanomaterial adsorption capacity toward MNZ was: HSAG100 < HSAG300 < N-rGO < HSAG400 < HSAG500 < GO < rGO and toward TMP was: HSAG100 < N-rGO ≈ HSAG300 < HSAG400 < HSAG500 ≈ rGO < GO; and except for GO, the adsorption capacity of the nanomaterials increased almost linearly with the surface area. At T = 25 °C, the maximum mass adsorbed of MNZ and TMP on GO were 190 and 218 mg/g, at pH 7 and pH 10, respectively. The adsorption of TMP and MNZ on GO corroborated the presence of different adsorption mechanisms dependent on antibiotic speciation and pH. The adsorption of both antibiotics on the materials based on graphite and reduced graphene oxide was predominantly due to π-π dispersive interactions.

Piezo-enhanced photodegradation of organic pollutants on Ag3PO4/ZnO nanowires using visible light and ultrasonic

An imperative challenge emerged in the area of photocatalysis is the recombination of photoinduced electron–hole, which severely restricts the photodegradation efficiency of organic pollutants. This study proposes a piezoelectric Ag3PO4/ZnO nanowire with enhanced degradation performance of organic pollutants. The proposed nanowire can generate a piezoelectric effect under ultrasonic vibration to promote the separation and transfer of photoinduced carriers. The Ag3PO4/ZnO nanowires are fabricated by a simple two-step approach, and its structure and properties are tested by various methods. Results show that the Ag3PO4 nanoparticles are attached on the surface of the ZnO nanowires, which endow the photocatalyst with enhanced absorption in the visible-light region. Photochemical and photoluminescence studies show that Ag3PO4/ZnO nanowires have good electron–hole pairs separation. Under light and ultrasonic radiation, Ag3PO4/ZnO nanowires (APZ-3) on a stainless steel mesh (3.0 × 3.0 cm, ~30 mg) show an optimum piezo-photocatalytic performance for MB with 98.16% degradation rate in 30 min. The reaction rate constants of piezo-photocatalytic Ag3PO4/ZnO nanowires (APZ-3) are 4.13 times of those conventional photocatalytic ZnO nanowires. In addition, the as-prepared sample is applied to the treatment of antibiotics in aqueous solutions, such as ciprofloxacin, norfloxacin, and ofloxacin, and achieves good degradation efficiency. The enhanced photocatalytic performance can be owed to the formation of the p–n heterojunction at the Ag3PO4/ZnO interface and the generation of the piezoelectric effect of ZnO nanowires in the degradation process. The results also demonstrate an economical way for practical applications in the degradation of organic pollutants at the industrial level.

Magnetite-metal organic framework core@shell for degradation of ampicillin antibiotic in aqueous solution

Fe3O4@SiO2@MIL-53-NH2 (Al) nanocomposite (FeSi@MN NC) in core@shell structure was prepared by the synthesis of NH2-MIL-53 (Al) on the Fe3O4@SiO2 nanoparticles (FeSi NPs) using hydrothermal method. For synthesis of NH2-MIL-53 (Al) on FeSi NPs, the salt linker was used instead of protonated linker. The NC was used as an active photocatalyst for photodegradation of ampicillin (AMP) in aqueous solution. Diffuse reflectance spectra (DRS) studies showed that the FeSi@MN NC absorbs visible light irradiation, and therefore, it can be photoactivated under visible light. The TEM image of FeSi@MN NC indicated the rose-leaves of the NH2-MIL-53(Al) have been well encapsulated on the surface of FeSi sample. The results showed that the FeSi@MN core@shell has the larger surface area, suitable superparamagnetism, and good photocatalytic activity for degradation of AMP. The FeSi@MN core–shell exhibited higher photocatalytic activity compared to Fe3O4@SiO2@MIL-53 (Al) (FeSi@M) core@shell.

Effective Elimination of Contaminant Antibiotics Using High-Surface-Area Magnetic-Functionalized Graphene Nanocomposites Developed from Plastic Waste.

The presence of pharmaceutical residues in aquatic environments represents a risk for the equilibrium of the ecosystem and may seriously affect human safety itself in the long term. To address this issue, we have synthesized functional materials based on highly-reduced graphene oxide (HRGO), sulfonated graphene (SG), and magnetic sulfonated graphene (MSG). The method of synthesis adopted is simple and inexpensive and makes use of plastic bottle waste as the raw material. We have tested the fabricated materials for their adsorption efficiency against two model antibiotics in aqueous solutions, namely Garamycin and Ampicillin. Our tests involved the optimization of different experimental parameters of the adsorption process, such as starting antibiotic concentration, amount of adsorbent, and time. Finally, we characterized the effect of the antibiotic adsorption process on common living organisms, namely Escherichia coli DH5α (E. coli DH5α) bacteria. The results obtained demonstrate the efficiency of the method in addressing the issue of the emergence of antibiotic-resistant bacteria, which will help in preventing changes in the ecosystem.

Photocatalytic Degradation of Rifampicin: Influencing Parameters and Mechanism

The photocatalytic degradation of rifampicin antibiotic in aqueous solution under solar irradiation is investigated using ZnO as photocatalyst. The effect of experimental parameters such as ZnO load, initial rifampicin concentration, pH and the presence of salts (NaCl, NaHCO3, and Na2SO4) is studied. The kinetic study using the Langmuir-Hinshelwood model is also reported. A photocatalytic degradation mechanism is proposed.

Photocatalytic degradation of cefoxitin sodium antibiotic using novel BN/CdAl2O4 composite

The presence of the antibiotics in wastewater and drinking water is of growing concern worldwide, thereby an advanced sustainable technology needs to be developed to decontaminate the antibiotics from water resources. Herein, a series of novel boron nitrile/cadmium aluminate (BN/CdAl2O4) composites photocatalysts were synthesized by using hydrothermal methodology. Thus synthesized BN/CdAl2O4 composites were tested for the photocatalytic degradation of cefoxitin sodium (CFT) antibiotic in aqueous solution. The spectroscopic analysis confirmed that the morphology, N2 adsorption-desorption, and optical properties of the composites changes as the amount of the BN varies in BN/CdAl2O4 composite. The resulting BN/CdAl2O4 composite with a fraction of 0.2 g BN showed most efficient photocatalytic properties than the pure BN, CdAl2O4 and other BN/CdAl2O4 composites owing to its better light-harvesting properties, higher surface area, and better charge separation properties. The results revealed that the solution pH, irradiation times, and initial CFT concentration in solution controls the photocatalytic process and almost 100% CFT degradation was observed at 15 mg/L concentration within 240 min at pH 7. The results of free radicals scavenging experiments demonstrated that both positive hole and •OH free radical play dominant roles in CFT degradation. The kinetic modeling of CFT photocatalysis process showed better fitting with the first-order kinetic model as compared to the zero-order and second-order kinetic models. This study revealed that BN-0.2/CdAl2O4 composite has better CFT degradation efficiency and excellent recyclability.

A Water-Stable Terbium(III)-Organic Framework as a Chemosensor for Inorganic Ions, Nitro-Containing Compounds and Antibiotics in Aqueous Solutions.

Effective detection of organic/inorganic pollutants, such as antibiotics, nitro-compounds, excessive Fe3+ and MnO4 - , is crucial for human health and environmental protection. Here, a new terbium(III)-organic framework, namely [Tb(TATAB)(H2 O)]⋅2H2 O (Tb-MOF, H3 TATAB=4,4',4''-s-triazine-1,3,5-triyltri-m-aminobenzoic acid), was assembled and characterized. The Tb-MOF exhibits a water-stable 3D bnn framework. Due to the existence of competitive absorption, Tb-MOF has a high selectivity for detecting Fe3+ , MnO4 - , 4-nirophenol and nitroimidazole (ronidazole, metronidazole, dimetridazole, ornidazole) in aqueous through luminescent quenching. The results suggest that Tb-MOF is a simple and reliable reagent with multiple sensor responses in practical applications. To the best of our knowledge, this work represents the first TbIII -based MOF as an efficient fluorescent sensor for detecting metal ions, inorganic anions, nitro-compounds, and antibiotics simultaneously.

Rapid Removal and Efficient Recovery of Tetracycline Antibiotics in Aqueous Solution Using Layered Double Hydroxide Components in an In Situ-Adsorption Process

This work demonstrates a simple approach for the efficient removal of tetracycline (TC) antibiotic from an aqueous solution. The in situ-adsorption removal method involved instant precipitation formation of mixed metal hydroxides (MMHs), which could immediately act as a sorbent for capturing TC from an aqueous solution, by employing layered double hydroxide (LDH) components including magnesium and aluminum ions in alkaline conditions. By using this approach, 100% removal of TC can be accomplished within 4 min under optimized conditions. The fast removal possibly resulted from an instantaneous adsorption of TC molecules onto the charged surface of MMHs via hydrogen bonding and electrostatically induced attraction. The results revealed that our removal technique was superior to the use of LDH as a sorbent in terms of both removal kinetics and efficiency. Moreover, the recovery of captured TC was tested under the influence of various common anions. It was found that 98% recovery could be simply achieved by using phosphate, possibly due to its highly charged density. Furthermore, this method was successful for efficient removal of TC in real environmental water samples.

Preparation of Iron-Loaded Granular Activated Carbon Catalyst and Its Application in Tetracycline Antibiotic Removal from Aqueous Solution.

The removal of tetracycline antibiotics from water is currently an important environmental issue. Here we prepared an iron-loaded granular activated carbon catalyst (GAC-Fe) through a one-step calcination method to remove tetracycline antibiotics from aqueous solution. The GAC-Fe was characterized by Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analysis. The effect of different influencing factors on the removal behavior of tetracycline antibiotics was studied, such as the solid-to-liquid ratio, H2O2 dosage, environmental temperature, initial pH, and contact time. The removal mechanism was explored through Fe ion dissolution and a free radical quenching experiment. The results show that the optimum solid-to-liquid ratio was 3.0 g∙L−1 and the suitable H2O2 dosage was 1.0 mL (3%). The applicable environmental temperature was 25 °C and the appropriate pH value was 2.0. The removal rate of tetracycline antibiotics tended to be stable in a contact time of 600 min. The main mechanism of tetracycline antibiotic removal by GAC-Fe was heterogeneous catalytic reaction through iron ion leaching and free radical inhibition experiment. The hydroxyl radical played a major role during the removal process. The partially dissolved iron ions initiated a homogeneous catalytic reaction. However, heterogeneous catalytic degradation was the main reaction. The GAC-Fe could still remove tetracycline antibiotics after five cycles, especially for methacycline and minocycline. Our work suggests that the GAC-Fe catalyst has potential as a remediation agent for tetracycline antibiotics in aqueous solution.

An Exceptionally Stable TbIII-Based Metal–Organic Framework for Selectively and Sensitively Detecting Antibiotics in Aqueous Solution

An exceptionally stable metal-organic framework based on one-dimensional (1D) TbIII chains with significant green emission under excitation energy, {[Tb(TATMA)(H2O)·2H2O} n (namely, 1), has been fabricated successfully under hydrothermal conditions. By virtue of the spectral overlap between the absorbance spectra of nitrofurans (NFAs) and the excitation spectrum of MOF 1, the resultant sample exhibits outstandingly sensitive and selective luminescence detectability for NFT ( Ksv = 3.35 × 104 M-1) and NFZ ( Ksv = 3.00 × 104 M-1) by quenching phenomenon. More importantly, it can detect NFAs in water from bovine serum samples. The portable MOF film can be easily prepared and used with excellent stability and recursitivity.

Experimental study of degradation and biodegradability of oxytetracycline antibiotic in aqueous solution using Fenton process

Experimental study of degradation and biodegradability of oxytetracycline antibiotic in aqueous solution using Fenton process

ZIF-8/ZIF-67 derived carbon for efficient removal of antibiotics in aqueous solution

In this paper, ZIF-8/ZIF-67 derived carbon (ZDC) was synthesized by surface modification technology and calculation process subsequently. In order to evaluate the feasibility of ZDC for antibiotic removal, the adsorption experiments were carried out by three typical antibiotics: tetracycline (TC), norfloxacin (NFO) and ofloxacin (OFO). The results showed that the maximum adsorption capacities of TC, NFO and OFO based on ZDC were 543.48, 239.8 and 340 mg/g, respectively. The adsorption capacity of ZDC was better than that of many other similar adsorbents, which is a potential adsorbent for antibiotic removal in the contaminated water.

Modeling of antibiotic degradation in sonophotocatalytic process, increasing biodegradability and process optimization by response surface methodology (RSM)

The aim of this study was to study the degradation of β-lactam antibiotics in aqueous solutions by ultrasonic along with UV/immobilized ZnO catalyst. The variables such as contact time, antibiotic concentration, and ZnO dose were studied according to the response surface methodology. In the optimum condition, the removal efficiency of 94.2% for PCG and 84.2% for CFX was obtained. The BOD5/COD ratio in the optimum condition increased from 0 to about 0.4. The quadratic and linear model was well fitted with test results (R2 = 0.871–0.996). The results showed that sonophotocatalytic process led to the effective degradation of the PCG and CFX and their enhanced biodegradability.

Adsorption Behavior and Mechanism of Sulfonamide Antibiotics in Aqueous Solution on a Novel MIL-101(Cr)@GO Composite

The occurrence of numerous antibiotics, such as sulfonamides (SAs), in environmental water has recently heightened concerns in consideration of their potential threat to human health and aquatic ec...

Nanostructured polyaniline based pipette tip solid phase extraction coupled with high-performance liquid chromatography for the selective determination of trace levels of three sulfonamides in honey and milk samples with the aid of experimental design methodology

In this study, a miniaturized solid-phase extraction based on 2-(hexyloxy) naphthalene-sulfate doped polyaniline polymer as a new nanostructured sorbent packed into a 200 μL pipette tip (PT-SPE) as a rapid and efficient method was developed for the simultaneous and selective extraction of three sulfonamide (SAs) antibiotics in aqueous solution. The resultant polymer was well characterized by FT-IR, UV–Vis., FESEM, EDX and XRD. In this strategy, the pipette tip containing the sorbent was matched to a syringe and the sample solution was loaded onto the sorbent using a microsyringe pump. The eluate was analyzed with high performance liquid chromatography using UV–Vis. spectrometry detection (HPLC/UV–Vis). In preliminary experiments, sample pH, sorbent dosage, sample volume and eluent volume were identified as critical variables affecting the solid phase micro-extraction of SAs by the developed sorbent. The response surface methodology (RSM) based on a rotatable central composite design (CCD) was employed for modeling the chromatographic peak areas of SAs as responses and optimized the effective extraction variables. This method is cost-effective because only 7.4 mg sorbent amount and 0.6 mL methanol as eluent were required for the extraction of analytes. The multiple response criteria were used to optimize simultaneous responses of the analytes using the desirability function. Under the optimal conditions, a good linear relationship between the peak areas and concentrations of the SAs was found in the range of 50–50,000 ng mL−1 with correlation coefficients above 0.999. The developed method was successfully applied to the analysis of SAs in milk, and honey samples.

Sensor for ampicillin based on a microwave electrodynamic resonator

The paper describes a new biological sensor which represents a resonator based on a segment of a rectangular waveguide of 8 GHz band with shear dimensions of 28.5 × 12.6 mm2. On one side, the resonator is bounded by a metallic short-circuited wall; on the other side, it is bounded by a lithium niobate plate with a porous polystyrene film. This film, applied by centrifugation and modified in high-frequency discharge plasma in argon, was used to immobilize cells of Escherichia coli K-12. This resonator was connected through a coaxial-waveguide adapter to the S parameter meter, by means of which the reflection coefficient S11 in the plane of the lithium niobate plate was measured. The addition of an aqueous solution of ampicillin at 4–50 μg/ml to immobilized cells led to a significant change in the reflection coefficient of S11 from − 10.15 dB to − 15.09 dB. At the same time, the resonance frequency changed insignificantly within the range 8.06–8.068 GHz. The optimal time for modifying the polystyrene film for obtaining the required porosity and the optimal time for the immobilization of the bacterial cells were determined. The immobilized cells retained their activity for 4 months at a temperature of 4 °C. The study showed the promise of such a biosensor to determine β-lactam antibiotics in aqueous solutions by using ampicillin as an example. The limit of detection of the developed biosensor with respect to ampicillin was established (4 μg/ml).