Mineralization Of Tetracycline Research Articles

Catalytic PMS oxidation universality of CuFe2O4/MnO2 heterojunctions at multiple application scenarios

The magnetic CuFe2O4/MnO2 heterojunctions were prepared by hydrothermal method, and the effect of different reaction temperature on the physicochemical properties and catalytic activity was investigated. The CuFe2O4/MnO2 heterojunctions prepared at 100 °C can effectively activate peroxymonosulfate (PMS) at multiple application scenarios for degradation and mineralization of tetracycline, o-nitrophenol and ceftriaxone sodium under indoor light, visible light and dark condition. Additionally, the CuFe2O4/MnO2-PMS system showed high catalytic activity and anti-interference ability for degradation of pharmaceutical pollutants in natural water bodies and industrial wastewater. The TC removal efficiency in Qianhu Lake water, Ganjiang River water and tap water was about 88%, 92% and 89%, respectively. The CuFe2O4/MnO2-PMS system is also effective for actual pharmaceutical wastewater treatment with 77.9% of COD removal efficiency. Interestingly, the reactive species of CuFe2O4/MnO2-PMS system under visible light are different from those in dark condition, and the different catalytic mechanisms at multiple application scenarios were proposed. This work provides new insights into mechanism exploration of heterojunction catalyst for PMS activation.

Electrodeposited manganese oxides as efficient photocatalyst for the degradation of tetracycline antibiotics pollutant

One of the important environmental challenges of the 21st century is the effective removal of pollutants from the aquatic environment. In this study, electrodeposited manganese oxides (MnyOx) films were applied as visible-light-driven photocatalyst for the removal and mineralization of Tetracycline (TC) antibiotics. The photocatalytic activity of as-deposited and annealed MnyOx was tested at different pH values using LED visible illumination, resulting in 92.4 % of TC mineralization efficiency after 180 min for the best performing manganese oxide. Quenching experiments showed that hydroxyl radicals (OH) are the main active species responsible for the TC degradation. The photocorrosion of MnyOx has been studied by quantifying the concentration of the dissolved manganese cations during the photocatalytic experiments. By comparing the catalyst mass loss with the % of TC mineralization, we revealed that the degradation of the oxide surface structure is the factor that, more than the photocorrosion, is limiting the photocatalytic activity of MnyOx films. Finally, the photocatalytic mechanism of TC mineralization is proposed based on the detection of the intermediates species of the mineralization process by High-Performance Liquid Chromatography Mass-Spectroscopy. The facile synthesis process and the superior mineralization rate can open up a new approach for the possible large-scale utilization of electrodeposited MnyOx films as an effective visible light photocatalyst.

Preparation of Porous Ti/RuO2-IrO2@Pt, Ti/RuO2-TiO2@Pt and Ti/Y2O3-RuO2-TiO2@Pt Anodes for Efficient Electrocatalytic Decomposition of Tetracycline

Electrocatalytic oxidation (ECO) has attracted attention because of its high efficiency and environmental friendliness in water treatment. The preparation of anodes with high catalytic activity and long service lifetimes is a core part of electrocatalytic oxidation technology. Here, porous Ti/RuO2-IrO2@Pt, Ti/RuO2-TiO2@Pt, and Ti/Y2O3-RuO2-TiO2@Pt anodes were fabricated by means of modified micro-emulsion and vacuum impregnation methods with high porosity titanium plates as substrates. The scanning electron microscopy (SEM) images showed that RuO2-IrO2@Pt, RuO2-TiO2@Pt, and Y2O3-RuO2-TiO2@Pt nanoparticles were coated on the inner surface of the as-prepared anodes to form the active layer. Electrochemical analysis revealed that the high porosity substrate could result in a large electrochemically active area, and a long service life (60 h at 2 A cm-2 current density, 1 mol L-1 H2SO4 as the electrolyte, and 40 °C). The degradation experiments conducted on tetracycline hydrochloride (TC) showed that the porous Ti/Y2O3-RuO2-TiO2@Pt had the highest degradation efficiency for tetracycline, reaching 100% removal in 10 min with the lowest energy consumption of 167 kWh kg-1 TOC. The reaction was consistent with the pseudo-primary kinetics results with a k value of 0.5480 mol L-1 s-1, which was 16 times higher than that of the commercial Ti/RuO2-IrO2 electrode. The fluorospectrophotometry studies verified that the degradation and mineralization of tetracycline were mainly ascribed to the •OH generated in the electrocatalytic oxidation process. This study thus presents a series of alternative anodes for future industrial wastewater treatment.

Enhanced Activation of Peroxymonosulfate for Tetracycline Degradation Using CoNi-Based Electrodeposited Films

Synthesizing efficient heterogeneous catalysts with multiple active sites able to activate peroxymonosulfate (PMS) for the degradation of persistent organic pollutants continues to be a challenge for societies worldwide. In response, cost-effective, eco-friendly oxidized Ni-rich and Co-rich CoNi micro-nanostructured films were fabricated following a two-step process based on simple electrodeposition using green deep eutectic solvent as an electrochemical media and thermal annealing. The CoNi-based catalysts demonstrated exceptional efficiency in the heterogeneous catalyzed activation of PMS for tetracycline degradation and mineralization. The effects of the catalysts' chemical nature and morphology, the pH, the concentration of PMS, irradiation with visible light, and the duration of contact with the catalysts on the degradation and mineralization of tetracycline were also studied. In dark conditions, oxidized Co-rich CoNi degraded more than 99% of tetracyclines in only 30 min and mineralized more than 99% of them in only 60 min. Moreover, the degradation kinetics doubled from 0.173 min-1 in dark conditions to 0.388 min-1 under visible light irradiation. In addition, the material demonstrated excellent reusability and can be easily recovered with simple heat treatment. Given those findings, our work provides new strategies for constructing high-efficiency and cost-effective PMS catalysts and elucidating the effects of operational parameters and primary reactive species formed by the catalyst-PMS system on water treatment technologies.

Degradation and mineralization of tetracycline by Fenton process

In this study, we aimed to systematically optimize the operating parameters in the degradation and mineralization of tetracycline by Fenton process. For this purpose; optimum values were found for Fe2+ concentration, H2O2 concentration and pH, reaction time, sedimentation times which are effective operating parameters in Fenton process. In this study where initial tetracycline concentration was used as 100 mg/L; optimum values were found as 4 for pH, 30 mg/L for Fe2+ concentration, 100 mg/L for H2O2 concentration and 10 min for reaction time and 90 min for sedimentation time. Under these conditions, the TC degradation was 100%, while the COD removal efficiency was approximately 94%. As a result of kinetic studies, BMG is the most suitable kinetic model in terms of tetracycline degradation, while it is seen that the most suitable kinetic model for tetracycline mineralization in terms of COD is the first-order kinetic model. The cost of removing 1 kg of tetracycline from the unit costs of chemicals and energy used in the Fenton process was found to be 1.527$.

Heterogeneous photo-electro-Fenton degradation of tetracycline through nitrogen/oxygen self-doped porous biochar supported CuFeO2 multifunctional cathode catalyst under visible light

The nitrogen/oxygen self-doped porous biochar (NO/PBC) and NO/PBC supported CuFeO2 (CuFeO2-NO/PBC) were prepared and mixed as cathode catalysts for gas diffusion electrode (GDE) fabrication. The fabricated GDE could realize H2O2 electrogeneration and activate H2O2 to produce active radicals through NO/PBC and CuFeO2, respectively. The GDE with the NO/PBC to CuFeO2-NO/PBC ratio of 1:1 (CuFeO2-NO/PBC-GDE-1.0) possessed more superior catalytic performance for tetracycline degradation in heterogeneous photo-electro-Fenton (hetero-PEF) system under visible light than other as-fabricated GDEs. The •OH was primary species, and •O2- was auxiliary species for hetero-PEF degradation of tetracycline through CuFeO2-NO/PBC-GDE-1.0. The electron on the cathode surface and photoinduced electron could accelerate Fe3+/Fe2+ and Cu2+/Cu+ redox cycle, promoting •OH/•O2- production and tetracycline degradation. The toxicity estimation of tetracycline and intermediates, TOC removal and Escherichia coli growth inhibition confirmed that the remission of overall toxicity, the inhibition of antibacterial property and the mineralization of tetracycline were achieved in hetero-PEF system.

Degradation and mineralization of tetracycline and oxytetracycline by Fenton process: effect of inorganic anions

Degradation and mineralization of tetracycline and oxytetracycline by Fenton process: effect of inorganic anions

Combined Electro-Fenton and Anodic Oxidation Processes at a Sub-Stoichiometric Titanium Oxide (Ti4O7) Ceramic Electrode for the Degradation of Tetracycline in Water

The mineralization of tetracycline by electrochemical advanced oxidation processes (EAOPs) as well as the study of the toxicity of its intermediates and degradation products are presented. Electro-Fenton (EF), anodic oxidation (AO), and electro-Fenton coupled with anodic oxidation (EF/AO) were used to degrade tetracycline on carbon felt (cathode) and a sub-stoichiometric titanium oxide (Ti4O7) layer deposited on Ti (anode). As compared to EF and AO, the coupled EF/AO system resulted in the highest pollutant removal efficiencies: total organic carbon removal was 69 ± 1% and 68 ± 1%, at 20 ppm and 50 ppm of initial concentration of tetracycline, respectively. The effect of electrolysis current on removal efficiency, mineralization current efficiency, energy consumption, and solution toxicity of tetracycline mineralization were investigated for 20 ppm and 50 ppm tetracycline. The EF/AO process using a Ti4O7 anode and CF cathode provides low energy and high removal efficiency of tetracycline caused by the production of hydroxyl radicals both at the surface of the non-active Ti4O7 electrode and in solution by the electro-Fenton process at the cathodic carbon felt. Complete removal of tetracycline was observed from HPLC data after 30 min at optimized conditions of 120 mA and 210 mA for 20 ppm and 50 ppm tetracycline concentrations. Degradation products were elucidated, and the toxicity of the products were measured with luminescence using Microtox® bacteria toxicity test.

Novel Magnetic Fe3O4/α-FeOOH Nanocomposites and Their Enhanced Mechanism for Tetracycline Hydrochloride Removal in the Visible Photo-Fenton Process.

Magnetic Fe3O4/α-FeOOH heterojunction nanocomposites (denoted as Fe-NCs) have been synthesized by a fast one-pot hydrothermal method. The obtained Fe-NCs contain rich micropores with a high surface area of 135.15 m2/g. The different phases in the composites can efficiently enhance the visible-light absorption, improving the separation and transfer of photogenerated electron–hole pairs during the photocatalytic reaction. Thus, they show excellent degradation and mineralization of tetracycline (TC) over a wide pH range (5–9) in the visible photo-Fenton reaction. Especially, the catalyst exhibits the highest adsorption capacity toward TC at a neutral pH, which facilitates the surface reactions of TC with active species. Experiments evidence that the high production of photogenerated holes and superoxide radicals (O2•–) in Fe-NCs are favorable to the high catalytic efficiency. Combined with liquid chromatography–mass spectrometry, the possible pathway toward TC degradation was proposed.

Facile cost-effective fabrication of Cu@Cu2O@CuO–microalgae photocatalyst with enhanced visible light degradation of tetracycline

The widespread use and negative environmental effects of antibiotics have made their removal from aqueous media essential in terms of wastewater treatment. Accordingly, a hybrid helical Cu@Cu2O@CuO–microalgae photocatalyst for antibiotic photodegradation was synthesized in this study by a simple, inexpensive, and scalable process based on electroless Cu deposition and soft thermal treatment. The hybrid photocatalyst was more competitive for the photocatalytic degradation of tetracycline, especially in terms of mineralization and energy consumption, than state-of-the-art photocatalysts. The excellent photocatalytic performance is attributable to the effective formation of onion-like Cu@Cu2O@CuO heterojunctions, which synergistically lower the electron–hole recombination rate, promote the utilization of light and photogeneration of charge carriers, and decrease the photocorrosion activity. All these effects result in the enhanced photocatalytic degradation and mineralization of tetracycline. The high photocatalytic performance of the Cu@Cu2O@CuO–microalgae hybrids under LED irradiation resulted in a significantly lower electrical energy per order—i.e., the electrical energy required to diminish the tetracycline concentration by one order of magnitude in a unit of volume—of 57 kW h m−3 order-1. Importantly, the Cu@Cu2O@CuO–microalgae hybrids can easily be recycled after reaching their effective lifetime to fabricate competitive microalgal pellets, then integrated into a circular process in an environment–energy nexus to minimize the generation of residues.

Influence of CeO2 loading on the structural, textural, optical and photocatalytic properties of single-pot sol-gel derived ultrafine CeO2/TiO2 nanocomposites for the efficient degradation of tetracycline under visible light irradiation

A single-pot surfactant-free sol-gel method is reported for the facile and bulk synthesis of ultrafine-nanospherical CeO2/TiO2 composites with different CeO2 loadings and their photocatalytic-activity for the degradation and mineralization of tetracycline (TC) under visible-light irradiation is investigated for the first time. The incorporation of CeO2 favored the controlled crystalline growth of TiO2 in its anatase phase, and their crystallinity and particle size were significantly decreased. The textural and optical properties of TiO2 were also improved with the incremental addition of CeO2 by increasing their specific surface-area and visible-light absorption respectively. The optical band gap of TiO2 decreased to 2.24 eV with the incorporation of 1% CeO2 and it further decreased to 2.21 eV with the incremental amount of CeO2. Due to the formation of heterojunction in the composite, the recombination rate of electron-hole pairs was significantly decreased. A highest TC removal efficiency of ~99% was observed for 4% CeO2/TiO2 composite for a period of 80 min of visible-light irradiation. Moreover, 88.2% TC mineralization efficiency was achieved for a period of 240 min of visible light irradiation. The enhanced catalytic-activity could be attributed to the synergy of high degree of adsorption followed by an enhanced photocatalysis at the heterointerface formed by the adjacent contact between TiO2 and CeO2. The synergistic effects of low-particle size, high surface-area, enhanced visible-light absorption, reduced band-gap, and increased life-time of the photogenerated charge-carriers through the formation of heterointerface contributed to its high photocatalytic activity. The hydroxyl and superoxide-anion radicals played a superior role in the photocatalytic process. Moreover, the composites retained its efficiency for seven-cycles of reaction without any significant-loss in its activity and structural and textural stability.

Effective Removal of Tetracycline by Using Bio-Templated Synthesis of TiO2/Fe3O4 Heterojunctions as a UV–Fenton Catalyst

Novel maize-straw-templated TiO2/Fe3O4 hierarchical porous composites were synthesized by high-temperature calcination followed by a hydrothermal process. The composites were demonstrated to be efficient heterogeneous catalysts for the UV–Fenton-like degradation of TC. The results show that the as-prepared TiO2/Fe3O4 catalysts retain the original pore morphology of the maize-straw material, and a large amount of Fe3O4 particles are attached to the TiO2 surfaces. The as-prepared TiO2/Fe3O4 heterojunctions have abundant interfacial boundaries, which greatly improve the migration of photoexcited charges across different components. Consequently, in the UV–Fenton system, the TiO2/Fe3O4 catalysts exhibit significant activity towards the degradation of TC (50 mg/L) in a wide pH range. In particular, a maximum mineralization and TC removal of 98% is achieved within 60 min at pH 7.0, which is much higher than that of traditional Fe3O4-based UV–Fenton (81%) and TiO2 photocatalysis (23%). The enhanced degradation and mineralization of tetracycline is attributed to the efficient reduction of Fe3+ to Fe2+ by photo-generated electrons from the TiO2 skeleton of the TiO2/Fe3O4 heterojunction.

Great improvement on tetracycline removal using ZnO rod-activated carbon fiber composite prepared with a facile microwave method

New composite materials of activated carbon fiber (ACF) coated with zinc oxide (ZnO) were obtained by applying a green, cost-effective and rapid synthetic route using a commercial microwave oven. ZnO rods with a uniform and stable structure and an average diameter of 0.3–0.5μm and length of 1.0–1.5μm were achieved after only 3-min microwave treatment. The properties of ZnO were efficiently transferred to ACF, such that the resulting material, termed ZnO rod-ACF, demonstrated a promising potential as an efficient photocatalyst and simultaneously as an adsorbent. Pharmaceutical tetracycline at a concentration of 40mg/L was used to evaluate the organic pollutant removal capacity of the synthesized materials. At pH 8, ZnO rod-ACF exhibited excellent removal capacity (over 99%) and mineralization (90.7%) of tetracycline in aqueous solution within 1h under UV irradiation. The stability of ZnO rod-ACF was maintained and the mineralization of tetracycline was also maintained at 81.35% after multiple usage cycles. The photodegradation pathways of tetracycline were proposed based on the identified reaction intermediates.

Electrochemical degradation and mineralization of tetracycline on a boron-doped diamond electrode

Electrochemical oxidation of tetracycline on a boron-doped diamond electrode in order to develop a method for purification of waste water from contamination by pharmaceutical agents was studied. It was found that under these conditions deep oxidation of tetracycline (TC) down to its full mineralization can take place. Using high resolution mass spectrometry, it was shown that in the first stage of the reaction the oxidation of TC proceeds with the formation of products with higher molecular mass than TC, but with further electrolysis TC transforms into compounds with lower molecular mass, and then into inorganic compounds.

Tetracycline degradation and mineralization by the coupling of an electro‐Fenton pretreatment and a biological process

AbstractBACKGROUNDStudies on the degradation and mineralization of tetracycline by means of the electro‐Fenton process are lacking in the available literature. Its relevance as a pre‐treatment prior to a biological process for the removal of tetracycline was therefore examined.RESULTSDegradation followed pseudo‐first‐order kinetics and the optimal operating conditions were: 0.1 mmol L‐1 catalyst (Fe2+) concentration, 300 mA applied current intensity and 25 mg L‐1 tetracycline, leading to total degradation within only 5 min and a mineralization yield of 89 % after 6 h electrolysis. Biodegradability tests were realized with 100 mg L‐1 tetracycline; BOD5/COD ratio increased from 0.02 to 0.56 after 6 h electrolysis, showing the relevance of the electro‐Fenton pre‐treatment. However, to keep a significant residual organic content, 2 to 4 h electrolysis time may be more relevant, leading to BOD5/COD ratio and mineralization yields of 0.33–0.44 and 46–72%, respectively.CONCLUSIONActivated sludge cultures of pretreated and non‐pretreated tetracycline solutions were carried out for 3 weeks. The overall TOC removal increased from 28% for the non‐pretreated tetracycline to 68 and 86% after 2 and 4 h electrolysis, confirming the efficiency of the proposed combined process. © 2012 Society of Chemical Industry