Sonocatalytic removal of ampicillin by Zn(OH)F: Effect of operating parameters, toxicological evaluation and by-products identification

Degradation of Ampicillin with antibiotic activity removal using persulfate and submersible UVC LED: Kinetics, mechanism, electrical energy and cost analysis

Effective water treatment to remove antibiotics and its activity from contaminated water is urgently needed to prevent antibiotic-resistant bacteria (ARB) emergence. In this study, we investigated degradation of Ampicillin (AMP), an extensively used β-lactam antibiotic, using submersible Ultraviolet C Light Emitting Diode (λmax = 276 nm) irradiation source, and Persulfate (UVC LED/PS system). Pseudo first order rate constant (kobs) for degradation of AMP (1 ppm) by UVC LED/PS system was determined to be 0.5133 min-1 (PS = 0.2 mM). kobs value at pH 2.5 (0.7259 min-1) was found to be higher than pH 6.5 (0.5133 min-1) and pH 12 (0.1745 min-1). kobs value for degradation of AMP in deionized water spiked with inorganic anions (Cl-=0.5369 min-1,SO42-=0.4545 min-1, NO3-=0.1526 min-1, HCO3-=0.0226 min-1), in real tap water (0.1182 min-1) and simulated ground water (0.0372 min-1) were presented. Radical scavenging experiment reveal involvement of sulfate radical anion and hydroxyl radical in UVC LED/PS system. EPR analysis confirms the generation of sulfate radical anion and hydroxyl radical. Importantly, 74% reduction of total organic carbon (TOC) occurred within 60 min of AMP treatment by UVC LED/PS system. Seven degradation by-products were identified by high resolution mass spectrometry, and degradation pathways were proposed. Antibacterial activity of AMP towards Bacillus subtilis and Staphylococcus aureus was completely removed after UVC LED/PS treatment. ECOSAR model predicted no very toxic degradation by-products generation by UVC LED/PS system. Electrical Energy per order (EEo) and cost of UVC LED/PS system were determined to be 0.9351 kW/m3/order and ₹ 7.91/m3 ($ 0.095/m3 or € 0.087/m3), respectively. Overall, this study highlights, UVC LED/PS system as energy efficient, low-cost, and its potential to emerge as sulfate radical anion based advanced oxidation process (AOP) to treat water with antibiotics.

Sonocatalytic degrading antibiotics over activated carbon in cow milk

Herein, an efficient, simple and economical approach to remove antibiotics (ABX), i.e. ceftiofur hydrochloride, sulfamonomethoxine sodium (SMM), marbofloxacin and oxytetracycline by sonication with activated carbon (AC) from cow milk has been successfully implemented. The pseudo-first-order kinetics constants for the sonolytic and sonocatalytic degrading SMM are 0.036 and 0.093 min-1, respectively. The synergistic efficiency of removing ABX by using sonocatalysis reached 1.8-4.0. Hydrophobic ABX underwent faster degradation than hydrophilic ABX in sonocatalytic systems. Adding 0.5 mmol L-1 H2O2, the optimal concentration, improved the sonocatalytic degradation rates of ABX by 9.1%-28.5%. Surface area and dose of AC play crucial roles in the sonocatalysis of ABX. By sonicating 50 mL of 5.52 μmol L-1 ABX in milk at 500 kHz and 259 W with 20 mg AC for 20-60 min resulted in residual ABX concentrations ranging from 42.6 to 95.1 μg L-1, which meet the relative maximum residue limits set by European Commission.

Aqueous degradation of 6-APA by hydroxyl radical: a theoretical study

CONTEXT

Degradation reactions of micropollutants such as antibiotics with OH radicals are very important in terms of environmental pollution. Therefore, in this study, the degradation kinetic mechanism of 6-aminopenicillanic acid (6-APA) with OH radical was investigated by density functional theory (DFT) methods.

METHODS

For the calculations, different functionals such as B3LYP, MPW1PW91, and M06-2X were used with a 6-31 g(d,p) basis set. The aquatic effect on the reaction mechanism was investigated by conductor-like polarizable continuum model (CPCM). For the degradation kinetics in aqueous media, the addition of explicit water molecules was also calculated. Subsequent reaction mechanism for the most probable reaction product was briefly discussed.

RESULTS

Among the functionals used, B3LYP results were consistent with the experimental results. Calculated kinetic parameters indicated that the OH-addition path was more dominant than the H-abstraction paths. With the increase of explicit water molecules in the models, the energy required for the formation of transition state complexes decreased. The overall rate constant is calculated as 2.28 × 10¹¹ M^-1 s^-1 at 298 K for the titled reaction.

Highly Efficient NO2 Sensors Based on Al-ZnOHF under UV Assistance

Zinc hydroxyfluoride (ZnOHF) is a newly found resistive semiconductor used as a gas-sensing material with excellent selectivity to NO₂ because of its unique energy band structure. In this paper, Al³⁺ doping and UV radiation were used to further improve the gas-sensing performance of ZnOHF. The optimized 0.5 at.% Al-ZnOHF sample exhibits improved sensitivity to 10 ppm NO₂ at a lower temperature (100 °C) under UV assistance, as well as a short response/recovery time (35 s/96 s). The gas-sensing mechanism demonstrates that Al³⁺ doping increases electron concentration and promotes electron transfer of the nanorods by reducing the bandgap of ZnOHF, and the photogenerated electrons and holes with high activity under UV irradiation provide new reaction routes in the gas adsorption and desorption process, effectively promoting the gas-sensing process. The synergistic effect of Al³⁺ and UV radiation contribute to the enhanced performance of Al-ZnOHF.

Enhanced hydrolytic removal of tylosin in wastewater using polymer-based solid acid catalysts converted from polystyrene

Antibiotic production wastewater usually contains high concentrations of antibiotic residues, which can cause instability and deterioration of biological wastewater treatment units and also domestication and proliferation of antibiotic-resistance bacteria. An effective pretreatment on antibiotics production wastewater is expected to selectively reduce the concentration of antibiotics and decrease the toxicity, rather than mitigate organic and other contaminants before further treatments. In this work, two polymer-based solid acids, PS-S and CPS-S bearing high concentrations of -SOH₃ groups (up to 4.57 mmol/g), were prepared and successfully used for hydrolytic mitigation of 100 mg/L tylosin within 20 min. The co-existence of high concentrations of COD and humic substances did not affect the mitigation of tylosin obviously, while more than 500 mg/L of nitrogenous compounds suppressed the hydrolytic efficiency. Recycle and reuse experiments showed that the solid acids performed well in five cycles after regeneration. Three transformation products (P1, P2 and P3) were identified using UPLC-QTOF-MS/MS. Sugar moieties including mycarse, mycaminose, and mycinose detached and released simultaneously or in order from the 16-member lactone ring through desugarization, which led to a dramatic decrease in antibacterial activity as revealed by cytotoxicity evaluations using S. aureus. Ecotoxicity estimation indicated the acute toxicities of the hydrolyzed products to model species (e.g., fish, daphnid and green algae) were classified as "not harmful". This work suggested an effective and selective method to pretreat tylosin-contained production wastewater by using polymer-based solid acids. These results will shed light on effective elimination of antibiotics pollution from pharmaceutical industries through strengthening the pretreatments.

Synthesis of Fe-TiO2@Fe3O4 magnetic nanoparticles as a recyclable sonocatalyst for the degradation of 2, 4-dichlorophenol

2, 4-Dichlorophenol is a type of chlorophenol that, even at low concentrations, causes adverse effects such as anemia, coma, weakening of the nervous system, and cancer in humans and other organisms. Therefore, the aim of this study was to synthesize the Fe-TiO₂@Fe₃O₄ sonocatalyst and to assess the removal efficiency of 2, 4-dichlorophenol using this sonocatalyst. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), value-stream mapping (VSM), Brunauer Emmett Teller (BET), and diffuse reflectance spectroscopy (DRS) analyses were performed for characterizing the synthesized nanoparticles. The effect of different factors, such as pH (3-9), initial concentration 2, 4-dichlorophenol (20-80 mg/L), and level of nanoparticles (200-600 mg/L) at different time points (15-90 min), was assessed on sonocatalytic removal of 2, 4-dichlorophenol, and then the reaction kinetics, process mechanism, and stability of the synthesized nanoparticles were determined under optimal conditions. The highest removal efficiency of 2, 4-dichlorophenol and constant reaction rate was obtained at pH of 5, the initial concentration of 20 mg/L, and the nanoparticles dose of 400 mg/L under ultrasound with a frequency of 35 kHz following the reaction time of 90 min. The maximum mineralization efficiency (total organic carbon TOC) under optimal conditions was 81%. Analysis of the degradation kinetics indicated that the 2, 4-dichlorophenol degradation can follow a first-order reaction. The stability of the synthesized sonocatalyst decreased by 91% after 5 re-uses. This study confirmed the efficiency of the Fe-TiO₂@Fe₃O₄ sonocatalytic process in the degradation and mineralization of 2, 4-dichlorophenol.

Theoretical insights into the reaction mechanism and kinetics of ampicillin degradation with hydroxyl radical

CONTEXT

Ampicillin (AMP) is a penicillin-class beta-lactam antibiotic widely used to treat infections caused by bacteria. Therefore, due to its widespread use, this antibiotic is found in wastewater, and it contains long-term risks such as toxicity to all living organisms.

METHOD

In this study, the degradation reaction of ampicillin with hydroxyl radical was investigated by the density functional theory (DFT) method. All the calculations were performed with B3LYP functional at 6-31G(d,p) basis set.

RESULTS

The thermodynamic energy values and reaction rates of all possible reaction paths were calculated. The addition of the hydroxyl radical to the carbonyl group of the beta-lactam ring is thermodynamically the most probable reaction path. The calculated overall reaction rate constant is 1.36 × 10¹¹ M^-1 s^-1. To determine the effect of temperature on the reaction rate, rate constants were calculated for all reaction paths at five different temperatures. The subsequent reaction kinetics of the most preferred primary route was also examined, and the toxicity values of the intermediates were estimated. The acute toxicity of AMP and its degradation product were calculated using the Ecological Structure Activity Relationships (ECOSAR) software. The degradation product was found to be more toxic than AMP.

ZnO Nanorods Grown on Rhombic ZnO Microrods for Enhanced Photocatalytic Activity

In this paper, the formation of rhombic ZnO microrods surrounded by ZnO nanorods was realized on the surfaces of zinc foils using a hydrothermal method. The photocatalytic degradation of Rhodamine B solution was used to test the photocatalytic performance of the prepared samples. Compared with the rhombic Zn(OH)F and ZnO microrods grown on zinc foils, the hierarchical micro/nanostructures formed by ZnO nanorods surrounding the surfaces of rhombic ZnO microrods have better photocatalytic performance. The experimental results are mainly due to the fact that the hierarchical ZnO micro/nanostructures formed by ZnO nanorods surrounding the surface of the rhombic ZnO microrods have a larger surface area compared with the rhombic Zn(OH)F and ZnO microrods. More importantly, the photocatalytic circulation experiments indicate that ZnO nanorods grown on rhombic ZnO microrods can be recycled and have a relatively stable photocatalytic performance.

A novel electrochemically enhanced homogeneous PMS-heterogeneous CoFe2O4 synergistic catalysis for the efficient removal of levofloxacin

A novel electrochemically enhanced homogeneous-heterogeneous catalytic system was constructed by placing the prepared heterogeneous catalyst (CoFe₂O₄/NF) in parallel between the anode and the cathode for peroxymonosulfate (PMS) activation to remove levofloxacin (LVF) in this work. Over 90% of LVF could be effectively removed by the constructed system after 40 min's degradation. And the electrical energy consumption was only 2.51 kWh/m³, which was lower than 54.5% of the traditional electrochemical advanced oxidation process. Besides, the system broadened the response range of pH and overcame the inhibitory effect of alkaline conditions on degradation. These activities were mainly due to the high generation ability of free radical (SO₄^·-, ·OH and O₂^·-) and non-radical (¹O₂). And the SO₄^·- was found to be the main radical for LVF degradation. The high SO₄^·- generation ability was demonstrated to be resulted from the dual effects of synergy of CoFe₂O₄/PMS and enhancement of electrochemistry in EC/CoFe₂O₄/PMS system. In detail, electrochemistry could effectively promote the continuous circulation of Co²⁺/Co³⁺ and Fe²⁺/Fe³⁺ redox cycles on the surface of CoFe₂O₄ to enhance the activation of PMS, thereby generating SO₄^·-. This work can provide a promising and cost-effective approach to construct highly efficient organic pollutant degradation system.

Removal of Ciprofloxacin from Wastewater by Ultrasound/Electric Field/Sodium Persulfate (US/E/PS)

Ciprofloxacin (CIP), as a common antibiotic used in human clinical and livestock farming, is discharged into natural water bodies and its concentration has increased in the last years. Its stable chemical structure is difficult to remove by conventional techniques. Residual ciprofloxacin in the environment has become an emerging micropollutant that promotes the generation of resistance genes of bacteria and endangers ecosystem balance and human health. Removal of ciprofloxacin from water by the system of ultrasound/electric field/sodium persulfate (US/E/PS) was investigated. Firstly, CIP degradation affects by different oxidation methods, such as ultrasonic oxidation, electro-oxidation, and persulfate oxidation, and their four combined oxidation methods (ultrasound-activated persulfate oxidation, electro-activated persulfate oxidation, ultrasound-enhanced electro-oxidation, and ultrasound-enhanced electro-activated persulfate oxidation), on the target contaminants were compared. Secondly, the influences of parameters on the CIP degradation by an ultrasound-enhanced electro-activation-persulfate reaction system were investigated. Thirdly, the possible free radical species in the ultrasound-enhanced electro-activation-sulfate reaction system were identified and the dominant free radical species in the system were analyzed. Finally, the samples of CIP in the US/E/PS system were tested by liquid mass spectrometry, and the possible intermediate products and degradation path were speculated. The results indicate that the US/E/PS system is of great potential application value in the removal of organic pollution and environmental purification.

Optimization of photocatalytic degradation conditions and toxicity assessment of norfloxacin under visible light by new lamellar structure magnetic ZnO/g-C3N4

Degradation of norfloxacin (NFX) by zinc oxide (ZnO)/g-C₃N₄, a magnetic sheet ZnO with g-C₃N₄ on its surface was studied. Through a new preparation system method, hydrothermal reaction provides a solid-layered magnetic ZnO material basis, and the simple thermal condensation method was used to transform the urea into g-C₃N₄ on the magnetic sheet ZnO in a uniform and orderly manner to increase the stability and photocatalytic performance of the material. Compared with previous studies, the pore volume and photocatalytic performance of the material are improved, and became more stable. By studying the degradation effect of basic and photocatalytic materials prepared in different proportions, the kinetic constant of ZGF is 0.01446 (min^-1). The response surface methodology (RSM) was used to study the optimization and effect of solution pH (4-12), photocatalyst concentration (0.2-1.8 g/L), and NFX concentration (3-15 mg/L) on the degradation rate of NFX during photocatalytic degradation. The R² value of the RSM model was 0.9656. The NFX removal rate is higher than 90% when the amount of catalyst is 1.43 g/L, the solution pH is 7.12, and the NFX concentration is less than 8.61 mg/L. After 5 cycles, the degradation rate of magnetic materials decreased to 92.8% of the first time. The capture experiment showed that the photocatalytic machine Toxicities was mainly hole action. The TOC removal rate within 2 h was 30%, a special intermediate toxicity analysis method was adopted according to the characteristics of NFX's inhibitory effect on Escherichia coli community. The toxicity of degraded NFX solution disappeared, and the possibility of non-toxic harm of by-products was verified. LC-Q-TOF method was used to detect and analyze various intermediate products converted from NFX after photocatalytic degradation, and the photocatalytic degradation pathway of NFX was proposed.

Degradation of amoxicillin with sono, photo, and sonophotocatalytic oxidation under low-frequency ultrasound and visible light

The presence of pharmaceutically active compounds in aquatic bodies is a global concern, and suitable treatment technologies are required. In this study, the efficacy of photocatalytic, sonocatalytic, and sonophotocatalytic oxidation processes for the degradation of amoxicillin (AMX) was investigated using visible light with N doped TiO₂ (N-TiO₂) nanoparticles as the catalyst and low-frequency ultrasound in a novel multifrequency reactor. The influence of different operational parameters on the extent of AMX degradation was studied. Sonophotocatalytic oxidation was found more efficient for AMX degradation when compared to photocatalysis or sonocatalysis alone, and may be due to the reduced bandgap of the catalyst, enhanced cavitation effect due to the presence of the solid catalyst, and improved mass transfer of pollutants. AMX degradation during sono, photo, and sonophotocatalytic oxidation processes was in good agreement with pseudo-first-order kinetics. Empirical kinetic models were also developed using multiple linear regression for predicting the degradation efficiency accounting for the operational parameters. Scavenger experiments suggested that ^•OH radicals largely contributed to AMX degradation, and a plausible mechanism for degradation was proposed. Further, possible degradation pathways for all three treatment processes are also proposed after identifying the degradation products.

Substrate-Induced Growth of Micro/Nanostructured Zn(OH)F Arrays for Highly Sensitive Microfluidic Fluorescence Assays

To date, ZnO array-based microfluidic fluorescence assays have been widely investigated and have exhibited excellent performance in the detection of cancer biomarkers. However, the requirements of highly sensitive detection necessitate further improvement of current Zn-based fluorescence detection devices. Here, a rhombus-like Zn(OH)F array-based microfluidic fluorescence detection device is proposed. Construction of Zn(OH)F arrays on the inner wall of a microchannel is carried out via a microfluidic chemical method. A substrate-induced growth strategy for Zn(OH)F arrays is proposed, and various micro/nanostructured Zn(OH)F arrays are successfully obtained. Zn(OH)F nanorod arrays with a high aspect ratio can be constructed on the columnar ZnO nanorod arrays, and the results indicate that the fluorescence enhancement factor (EF) of the Zn(OH)F arrays toward Cy3 is approximately 4-fold that of the ZnO nanorod arrays, which can be attributed to the higher excitation light absorption and evanescent electric field. In human epididymis-specific protein 4 (HE4) detection, the limit of detection (LOD) reaches 9.3 fM, and the dynamic linear range is 10 fM to 100 pM. It has been demonstrated that Zn(OH)F nanorod array-based microfluidic devices are excellent fluorescence assay platforms that also provide a new design and construction strategy for fluorescence enhancement substrates for the detection of biomarkers.

Flower-like Hydroxyfluoride-Sensing Platform toward NO2 Detection

We report for the first time using zinc hydroxyfluoride (ZnOHF) for efficient NO₂ gas detection. The prepared ZnOHF had a unique flower-like architecture self-assembled by nanorods with a diameter of 150 nm and length of 2-3 μm. The sensing performance toward NO₂ detection indicated that the prepared ZnOHF exhibited high response (82.71), short response/recovery time (13 s/35 s) to 10 ppm of NO₂, and excellent selectivity at 200 °C, greatly outperforming the ZnO raw material. ZnOHF could work in a wide detection window ranging from 100 ppb to 50 ppm, implying its practical application prospects in both industry and daily life. The excellent sensing behavior of ZnOHF originated mainly from the negligible oxygen ions adsorbed on the material surface, which was caused by the higher work function of ZnOHF. Therefore, almost all conduction band electrons can be used in the NO₂ gas sensing.

Sonochemical processes for the degradation of antibiotics in aqueous solutions: A review

Antibiotic residues in water are general health and environmental risks due to the antibiotic-resistance phenomenon. Sonication has been included among the advanced oxidation processes (AOPs) used to remove recalcitrant contaminants in aquatic environments. Sonochemical processes have shown substantial advantages, including cleanliness, safety, energy savings and either negligible or no secondary pollution. This review provides a wide overview of the different protocols and degradation mechanisms for antibiotics that either use sonication alone or in hybrid processes, such as sonication with catalysts, Fenton and Fenton-like processes, photolysis, ozonation, etc.

Structural evolution and sulfuration of nickel cobalt hydroxides from 2D to 1D on 3D diatomite for supercapacitors

Transition metal nickel–cobalt hydroxides are widely used as electrode materials for supercapacitors due to their intriguing active component properties.

One-pot synthesis of Cr(III)-incorporated Zr(IV) oxide for fluoride remediation: a lab to field performance evaluation study

A low-cost Cr(III)-incorporated Zr(IV) bimetallic oxide (CZ) was synthesized by simple chemical precipitation method for removal of fluoride from contaminated water. The physicochemical properties of CZ before and after fluoride removal were established with several instrumental techniques such as TEM with elemental mapping, SEM with EDX, XRD, IR, XPS, zeta potential measurement, etc. Batch adsorption technique were carried out to understand the factors affecting fluoride adsorption, such as effects of initial pH, adsorbent dose, co-occurring ions, contact time, and temperature. The maximum adsorption capacity observed at pH between 5 and 7. The fluoride adsorption processes on CZ obeyed the pseudo-second-order rate equations and both Freundlich and DR isotherm models. The maximum adsorption capacity of 90.67 mg g^-1 was obtained. The thermodynamic parameters ΔH⁰ (positive), ΔS⁰ (positive), and ΔG⁰ (negative) indicating the fluoride sorption system was endothermic, spontaneous, and feasible. The CZ also successfully used as fluoride adsorbent for real field contaminated water collected from the Machatora district, Bankura, West Bengal, India. Graphical abstract Schematic representation of CZ synthesis and its application for lab as well as field water purification purpose.

Ali S, Salerno M, Eldin MSM. 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.