Dual promoted ciprofloxacin degradation by Fe0/PS system with ascorbic acid and pre-magnetization

Biodegradation of ciprofloxacin by a manganese-oxidizing fungus Cladosporium sp. XM01: Performance and transcriptome analysis

Biogenic manganese (Mn) oxidation presents a promising approach for ciprofloxacin (CIP) removal from wastewater, yet the interaction between Mn bio-oxidation and CIP degradation remains unclear. The Mn-oxidizing fungus Cladosporium sp. XM01 was selected as a model strain in this study, to explore the impacts of CIP on microbial growth, function and biotransformation. Results showed that CIP exhibited a promotive effect on the growth and Mn(II) oxidation capacity of XM01. After 192 h of cultivation, 39.80 %-69.19 % of CIP was removed by XM01 in the absence of Mn(II), while over 84 % was removed with 300 μM Mn(II), demonstrating both direct and Mn(II)-enhanced indirect degradation of CIP. Transcriptomic analysis revealed that the upregulation of ribosome, peroxisome, and tyrosine metabolism pathways enhanced XM01's adaptation to CIP and supported microbial growth. Cytochrome P450 (CYP450) enzymes were implicated as key mediators in CIP degradation. Additionally, in the presence of Mn(II), the further upregulation of transmembrane transporters, NAD(P)H dehydrogenase, and CYP450 indicated that Mn bio-oxidation enhanced XM01's adaptation and response to CIP, thereby accelerating its degradation. Proposed CIP degradation pathways include piperazine epoxidation, decarboxylation, and hydroxylation. This study advances the understanding of fungal Mn oxidation in antibiotic removal, emphasizing its potential in wastewater treatment.

How to enhance persulfate processes by external-field effects: From fundamentals to applications

Persulfate-based advanced oxidation processes (PS-AOPs) are considered as efficient techniques for the degradation of contaminants, whereas the effective activation methods for reactive oxygen species (ROS) generation play vital roles in PS-AOPs. However, the internal electric field mediated activation methods, like introducing chemicals and materials, are often restricted by their intrinsic properties. Conversely, the introduction of external fields can provide extra energy to remarkably enhance the PS activation performance from outside, acting as an additional impetus to promote the cleavage of OO bond and thus improve the generation efficiency of ROS. In this review, a comprehensive overview of the external field enhanced PS-AOPs from fundamentals to applications was introduced. Specifically, the activation mechanisms under different external fields, recent advances and their influencing factors, as well as potential practical applications of the external field enhanced PS-AOPs were summarized. The perspectives from the opportunity to challenge were thus made for future investigation. Therefore, this review is expected to give a systematic overview of external-field enhanced PS-AOPs, providing a new direction towards the improvement on catalytic efficiency of PS-AOPs through the rational utilization of external fields.

Enhancing photocatalytic performance of F-doped TiO2 through the integration of small amounts of a quinoline-based covalent triazine framework

We present the design and synthesis of a new quinoline-based covalent triazine framework (Quin-CTF) that combines two photoactive fragments within its structure (triazine and quinoline moieties). By hybridizing this CTF material with fluorine-doped titanium dioxide (F-TiO2), we prepared and characterized photocatalysts with enhanced performance that leverage the synergy between the two components for pollutant photodegradation in water. This F-TiO2@CTF hybrid system was evaluated for the photocatalytic degradation of methylene blue dye and a pharmaceutical compound such as ciprofloxacin as model water pollutants. The hybrid materials containing small amounts of CTF (0.5, 1, and 2 wt%) achieved remarkable photodegradation efficiencies, significantly outperforming their individual counterparts. The reactive oxidant species (ROS) involved in such processes catalyzed by F-TiO2 are different from those involved when pristine Quin-CTF or their hybrid materials are used. Furthermore, the hybrid materials demonstrated reusability, preserving high photocatalytic activity over multiple cycles. This work, therefore, highlights a promising strategy for designing cost-effective and eco-friendly photocatalytic systems via the incorporation of a small amount of CTF-based systems in a cheap material such as titanium dioxide, offering a sustainable and effective solution for mitigating water pollution.

Cu-doped waste-tire carbon as catalyst for UV/H2O2 oxidation of ofloxacin

Ofloxacin (OFX), commonly employed in the treatment of infectious diseases, is frequently detected in aquatic environments and poses potential ecological risks. UV/H2O2 oxidation has been recognized as an efficient approach for removing antibiotics. In this study, Cu-doped waste-tire carbon was prepared and used as a UV/H2O2 catalyst for the degradation of OFX. The results showed that the OFX removal was 89.3% within 90 min under the optimal reaction conditions. It was found that ZnO, used in the tire manufacturing to promote rubber vulcanization for enhanced stability and durability, played an important role in UV/H₂O₂ oxidation for OFX degradation. Toxicity experiments conducted with a microbial degradation respirometer demonstrated that the treated water exhibited low toxicity. This study introduces a sustainable catalyst derived from waste tires, and facilitating the development of metal-carbon catalysts for the effective removal of antibiotics from wastewater.

Removal of sulfamethoxazole by Fe(III)-activated peracetic acid combined with ascorbic acid

Ascorbic acid (AA) was used as a reducing agent to improve the Fe(III)-activated peracetic acid (PAA) system for the removal of sulfamethoxazole (SMX) in this work. The efficiency, influencing factors and mechanism of SMX elimination in the AA/Fe(III)/PAA process were studied. The results exhibited that AA facilitated the reduction of Fe(III) to Fe(II) and subsequently improved the activation of PAA and H2O2. Various radicals, including organic radicals (e.g. CH3C(O)O• and CH3C(O)OO•) and hydroxyl radical (HO•), were rapidly formed from the activated PAA and H2O2, resulting in SMX removal. Increasing dosages of PAA and Fe(III) contributed to enhanced SMX degradation, while excessive PAA and Fe(III) did not further promote SMX degradation. Due to the radicals' quenching effect, excess AA hindered SMX elimination in the AA/Fe(III)/PAA process. The presence of HCO 3 - and Cl- inhibited SMX removal in this system, whereas NO 3 - , SO 4 2 - and natural organic matter had little impact on SMX degradation. The transformation pathways of SMX in the AA/Fe(III)/PAA system included hydroxylation, bond cleavage and amino oxidation. This research provides a strategy to enhance the Fe(III)-activated PAA system for the elimination of refractory organic pollutants.

Waste control by waste: A new approach for antibiotic removal and metal reuse from livestock wastewater using ascorbic acid-enhanced CaO2/Cu(II) system

Aiming at the coexistence of antibiotics and Cu(II) in livestock wastewater, a novelty strategy for the simultaneous removal of antibiotics and Cu ions by in-situ utilization of Cu(II) (i.e., CP/Cu(II) and CP/Cu(II)/ascorbic acid (AA) systems) was proposed. The removal rate of florfenicol (FF) in the CP/Cu(II)/AA system was 6.9 times higher than that of the CP/Cu(II) system. CP/Cu(II)/AA system was also effective in removing antibiotics from real livestock tailwater. Simultaneously, the removal of Cu ions in CP/Cu(II) and CP/Cu(II)/AA systems could reach 54.5 % and 15.7 %, respectively. The added AA could significantly enhance the antibiotics degradation but inhibit the Cu ions removal. HO•, O2•-, Cu(III), and •C-R were detected in the CP/Cu(II)/AA system, in which HO• was confirmed as the predominant contributor for FF degradation, and Cu(III) and •C-R also participated in FF elimination. The role of AA could accelerate HO• production and Cu(I)/Cu(II)/Cu(III) cycle, and form •C-R. The degradation products and pathways of FF in the CP/Cu(II)/AA system were proposed and the toxicity of the degradation products was evaluated by the toxicity analysis software (T.E.S.T). The results of this work suggest that without introducing complex catalysts, the feasibility of in-situ utilization of Cu(II) inherently or artificially introduced in livestock wastewater activating CP for antibiotic degradation and Cu ions removal was verified.

From wastewater to clean water: Recent advances on the removal of metronidazole, ciprofloxacin, and sulfamethoxazole antibiotics from water through adsorption and advanced oxidation processes (AOPs)

Antibiotics released into water sources pose significant risks to both human health and the environment. This comprehensive review meticulously examines the ecotoxicological impacts of three prevalent antibiotics-ciprofloxacin, metronidazole, and sulfamethoxazole-on the ecosystems. Within this framework, our primary focus revolves around the key remediation technologies: adsorption and advanced oxidation processes (AOPs). In this context, an array of adsorbents is explored, spanning diverse classes such as biomass-derived biosorbents, graphene-based adsorbents, MXene-based adsorbents, silica gels, carbon nanotubes, carbon-based adsorbents, metal-organic frameworks (MOFs), carbon nanofibers, biochar, metal oxides, and nanocomposites. On the flip side, the review meticulously examines the main AOPs widely employed in water treatment. This includes a thorough analysis of ozonation (O3), the photo-Fenton process, UV/hydrogen peroxide (UV/H2O2), TiO2 photocatalysis, ozone/UV (O3/UV), radiation-induced AOPs, and sonolysis. Furthermore, the review provides in-depth insights into equilibrium isotherm and kinetic models as well as prospects and challenges inherent in these cutting-edge processes. By doing so, this review aims to empower readers with a profound understanding, enabling them to determine research gaps and pioneer innovative treatment methodologies for water contaminated with antibiotics.

Potential of metallurgical iron-containing solid waste-based catalysts as activator of persulfate for organic pollutants degradation

The production of solid wastes in the metallurgical industry has significant implications for land resources and environmental pollution. To address this issue, it is crucial to explore the potential of recycling these solid wastes to reduce land occupation while protecting the environment and promoting resource utilization. Steel slag, red mud, copper slag and steel picking waste liquor are examples of solid wastes generated during the metallurgical process that possess high iron content and Fe species, making them excellent catalysts for persulfate-based advanced oxidation processes (PS-AOPs). This review elucidates the catalytic mechanisms and pathways of Fe2+ and Fe0 in the activation PS. Additionally, it underscores the potential of metallurgical iron-containing solid waste (MISW) as a catalyst for PS activation, offering a viable strategy for its high-value utilization. Lastly, the article provides an outlook towards future challenges and prospects for MISW in PS activation for the degradation of organic pollutants.

Ag-based coordination polymer-enhanced photocatalytic degradation of ciprofloxacin and nitrophenol

Transition-metal coordination complexes have attracted wide attention in molecular chemistry, but their applications still confront a tremendous challenge. Herein, a novel silver coordination polymer with a formula of {[Ag9(TIPA)6](NO3)9·12H2O}n (Ag-TIPA) was prepared by a solvothermal reaction of silver nitrate with triangular tris(4-imidazolylphenyl)amine (TIPA). The crystalline molecular structure was determined by single-crystal X-ray diffraction, which showed that each Ag(I) was coordinated with two nitrogen atoms of TIPA ligands. Such Ag-TIPA was used as a catalyst for the photodegradation of ciprofloxacin and 4-nitrophenol under UV-visible light irradiation. The results exhibited excellent photocatalytic performance and reusability due to high structure stability in an acidic, neutral and alkaline environment. The experimental findings and density functional theory calculations revealed that metal-ligand charge transfer in Ag-TIPA extended the absorption range of light and improved the charge transfer properties of TIPA. To further understand the photodegradation process, the intermediates were predicted and analysed through electrostatic potential, orbital weighted dual descriptor, and liquid chromatography-mass spectrometry techniques. Based on these findings, a possible degradation mechanism was proposed. This study provides new insights into the design and synthesis of Ag-based coordination polymers with novel structures, excellent catalytic activity, and good durability.