Degradation of tetracycline antibiotics by Fe2+-catalyzed percarbonate oxidation

Bioelectrochemistry increases the risk of resistance genes proliferation and transfer with sulfamethoxazole pressure decreasing in constructed wetlands: An overlooked double-edged effect.

Sonocatalytic degradation of tetracycline antibiotic using zinc oxide nanostructures loaded on nano-cellulose from waste straw as nanosonocatalyst

Enhanced photocatalytic activity for tetracyclines degradation with Ag modified g-C3N4 composite under visible light

Slower antibiotics degradation and higher resistance genes enrichment in plastisphere

Carbon-based heterostructure from multi-photo-active nanobuilding blocks SrTiO3@NiFe2O4@Fe0@Ni0@CNTs with derived nanoreaction metallic clusters for enhanced solar light-driven photodegradation of harmful antibiotics

The degradation of antibiotic tetracycline by using electron beam irradiation was investigated in an aqueous solution as a function of irradiation dose. The degradation efficiency of tetracycline was a level of 100% at an irradiation dose of 5 kGy. The degradation of tetracycline follows an apparent a “first order” reaction rate dependent on irradiation dose. Electron beam technology is suggested to be a way to degrade antibiotics and may be used as an approach for biological treatment of domestic and livestock wastewater.

Tetracycline degradation by a mixed culture of halotolerant fungi-bacteria under static magnetic field: Mechanism and antibiotic resistance genes transfer.

Waterborne disease is a global burden, which is mainly caused by waterborne pathogens disseminated through unsafe water, inadequate sanitation, and hygiene. Antibiotic resistance, which can also spread in water, has become an increasingly serious global health threat as it can prevent the effective treatment of infectious diseases. Improvements on water treatment and detection are the two critical strategies to control the surveillance of waterborne pathogens as well as antibiotic resistance bacteria and genes. The advancement in photo- and electro-chemical methods may provide more opportunities on decentralized water treatment and on-site pathogen monitoring under source-limited conditions. This thesis is dedicated to exploring the possible solutions to automatic, rapid, and easy-to-use in situ pathogen analysis for environmental water by adopting photo- or electro-chemical method, and to enhanced removal of antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) from wastewater by combining photo- and electro-chemical techniques. These include removal of ARB and ARGs by UV-assisted electrochemical treatment, electrochemical cell lysis (ECL) for DNA extraction from bacteria, and sunlight-activated propidium monoazide (PMA) pretreatment for live/dead bacteria differentiation by quantitative real-time polymerase chain reaction (qPCR) detection. Both experimental approaches and computational modelling were used to evaluate the performance of the techniques and to bring more insights into the mechanism. Each study presents a demonstration on real environmental or wastewater to access the potential of their applications under complex environmental parameters. UV-assisted electrochemical treatment for ARB and ARGs was conducted using a blue TiO₂ nanotube array (BNTA) anode. The inactivation of tetracycline- and SMX-resistant E. coli and the corresponding plasmid coded genes (tetA and sul1) damage was measured by plate counting on selective agar and qPCR, respectively. As a comparison of UV treatment alone, the enhanced reduction of both ARB and ARGs was achieved by UV-assisted electrochemical oxidation (UV-EO) without Cl⁻ and was further facilitated with the presence of Cl⁻, which is attributed to the in-situ generated oxidants by electrochemical process. Significantly slower removal of ARG than ARB was observed for both UV irradiation alone and UV-EO treatment, wherein intracellular ARG generally reduced slower than extracellular ones, and short amplicons reduced significantly slower than long ones. The predominant nucleotide damage by UV irradiation and conformational change by UV-EO treatment was visualized by DNA gel electrophoresis for treated extracellular ARGs. The mechanism on ARB and ARGs damage was further understood by computational chemical modeling. The slower reduction was found for the native bacteria and genes, tetA and sul1, in the latrine wastewater than that in laboratory-prepared buffered samples. The result emphasizes that all the UV-based techniques may only apply after other treatments to avoid the impairment by the transmittance, color, and particulate material in environmental or wastewater. A comprehensive investigation was conducted for ECL in terms of its performance on DNA extraction from gram-negative bacteria (Escherichia coli and Salmonella Typhi) and gram-positive bacteria (Enterococcus durans and Bacillus subtilis). A milliliter-output ECL device was developed based on the disruption of the cell membrane by OH⁻ that can be generated locally at the cathode and accumulated improvingly through a cation exchange membrane. Both gram-negative and gram-positive bacteria were successfully lysed within 1 min at a low voltage of ~5 V. To better understand the pH effects on cell lysis, the pH profile at the cathode surface and in bulk cathodic effluent was simulated via hydroxide transport in the cathodic chamber. The demonstration of ECL on various environmental water sample types (including pond water, treated wastewater, and untreated wastewater) showed its potential as a prelude to nucleic-acid based analyses of waterborne bacteria in the field. Propidium monoazide (PMA), a nucleic acid-binding dye, has been used to distinguish live from dead cells prior to PCR-based detection. To explore the off-the-grid application of PMA, sunlight was investigated for PMA activation as an alternative light source to a typical halogen lamp. PMA was successfully activated by a solar simulator, and the pretreatment conditions were optimized with respect to the PMA concentration as 80 µM and the exposure time as 10 min. The optimal PMA pretreatment was tested on four different bacteria species (two gram-positive and two gram-negative), and the effects of sunlight intensity and multi-sequential treatment were studied. Sunlight-activated PMA pretreatment was eventually demonstrated on latrine wastewater samples with natural sunlight on both sunny and cloudy days. The results showed the potential of sunlight-activated PMA pretreatment to be integrated into a lab-on-a-chip (LOAC) PCR device for off-the-grid microbial detection and quantification.

Mechanistic insight of simultaneous removal of tetracycline and its related antibiotic resistance bacteria and genes by ferrate(VI)

Insights into the effects of natural pyrite-activated sodium percarbonate on tetracycline removal from groundwater: Mechanism, pathways, and column studies

Efficient antibiotics removal via the synergistic effect of manganese ferrite and MoS2

Aquatic plants used in lake remediation accumulate heavy metals, turning biomass into waste. Herein, biochar (M-AcBC) derived from metal-laden Acorus calamus was combined with sodium percarbonate (SPC) and UV light to degrade tetracycline (TC). M-AcBC contained dispersed CuO, ZnO, and Fe3O4, exhibited defect structures, higher graphitization, and larger surface area than pristine biochar. Under optimal conditions (1.0 g/L M-AcBC, 0.3 mM SPC, pH 3, 900 µW/cm² UV), 90% TC removal was achieved. During the dark phase (0–40 min), functional groups, persistent radicals, and Fe₃O₄ activated SPC to generate •OH, • O 2 - , and 1O2. Upon UV irradiation (40–120 min), ZnO produced electron-hole pairs that further formed •OH and • O 2 - . The system exhibited synergistic effects, good reusability, broad applicability to various antibiotics, and reduced ecotoxicity of intermediates. This work provides a waste-to-resource strategy and new insights into the M-AcBC/SPC/UV system for water treatment.

Efficient activation of peroxymonosulfate by Co/Cu co-substituted-ferrite and carbon composite for rapid degradation of tetracycline in aqueous phase: Performance evaluation and mechanisms

Responses and successions of sulfonamides, tetracyclines and fluoroquinolones resistance genes and bacterial community during the short-term storage of biogas residue and organic manure under the incubator and natural conditions

Designing an inexpensive, easily synthesized, stable and efficient photocatalyst is a major challenge in photocatalysis area, especially when photo-reaction is performed in aquatic medium to degrade organic pollutants. To this aim, nano-sized MIL-101(Cr) (MIL = Materials Institute Lavoisier), as chemically tolerant metal-organic framework (MOF), was simply prepared via HF-free hydrothermal synthesis procedure. In order to decorate amorphous FeOOH quantum dots (QDs) on the surface of this MOF, various amounts of FeOOH QDs (i.e., 5, 10, 15 and 20 wt%) were synthesized in the presence of MIL-101(Cr) to prepare MIL-101(Cr)/FeOOH(x%) nanocomposites. Decoration of such iron oxide quantum dots on the surface of MIL-101(Cr) and investigation of its activity in photo-Fenton degradation of tetracycline (TC) antibiotic is reported here for the first time. Among the synthesized nanocomposites, MIL-101(Cr)/FeOOH(15%) demonstrated superior photo-Fenton activity in degradation of TC (80%) at short reaction time under optimum reaction condition using the energy-efficient white LED lamps as visible light source. It was observed that the synergy between any component of this photo-Fenton system such as nanocomposite, hydrogen peroxide and visible light is the main reason for enhancement of TC removal over time. Also, neither MIL-101(Cr) nor FeOOH QDs exhibited poor degradation efficiency, which implies the positive role of the coupling of these materials. Furthermore, the stability and recoverability of MIL-101(Cr)/FeOOH(15%) nanocomposite was investigated in four photo-Fenton cycles, which no significant decrease in TC degradation performance was observed.