Search Results (505)

Iopamidol (IPM), as a typical recalcitrant emerging pollutant and precursor of iodinated disinfection by-products (I-DBPs), is unsuccessfully removed by conventional wastewater treatment processes. This study comprehensively evaluated the ozone/peracetic acid (O₃/PAA) process for IPM degradation, focusing on degradation kinetics, environmental impacts, transformation products, ecotoxicity, disinfection byproducts (DBPs), and microbial inactivation. The O₃/PAA system synergistically activates PAA via O₃ to generate hydroxyl radicals (^•OH) and organic radicals (CH₃COO^• and CH₃CO(O)O^•), achieving an IPM degradation rate constant of 0.10 min⁻¹, which was significantly higher than individual O₃ or PAA treatments. The degradation efficiency of IPM in the O₃/PAA system exhibited a positive correlation with solution pH, achieving a maximum degradation rate constant of 0.23 min⁻¹ under alkaline conditions (pH 9.0). Furthermore, the process demonstrated strong resistance to interference from coexisting anions, maintaining robust IPM removal efficiency in the presence of common aqueous matrix constituents. Furthermore, quenching experiments revealed ^•OH dominated IPM degradation in O₃/PAA system, while the direct oxidation by O₃ and R-O^• played secondary roles. Additionally, based on transformation products (TPs) identification and ECOSAR predictions, the primary degradation pathways were elucidated and the potential ecotoxicity of TPs was systematically assessed. DBPs analysis after chlorination revealed that the O₃/PAA (2.5:3) system achieved the lowest total DBPs concentration (99.88 μg/L), representing a 71.5% reduction compared to PAA alone. Amongst, dichloroacetamide (DCAM) dominated the DBPs profile, comprising > 60% of total species. Furthermore, the O₃/PAA process achieved rapid 5–6 log reductions of E. coli. and S. aureus within 3 min. These results highlight the dual advantages of O₃/PAA in effective disinfection and byproduct control, supporting its application in sustainable wastewater treatment. Full article

As a result of the catalytic decomposition of H₂O₂, hydroxyl radicals are produced. Hydroxyl radicals are strong oxidants and effectively inactivate bacteria, ensuring water disinfection without toxic chlorinated organic by-products. The kinetics of bacterial inactivation were studied in a laboratory-scale flow catalytic reactor. A granular cobalt ferrite catalyst was thoroughly characterized using XRD and XRF techniques, SEM with EDS, and Raman spectroscopy. At lower H₂O₂ concentrations, H₂O₂ decomposition follows first-order reaction kinetics. At higher H₂O₂ concentrations, the obtained kinetics lines suggest that the reaction order increases. The kinetics of bacterial inactivation in the developed flow reactor depends largely on the initial number of bacteria. The initial bacterial concentrations in laboratory tests were within the range typical of real river water. A regression model was developed that relates the degree of bacterial inactivation to the initial number of bacteria, the initial H₂O₂ concentration, and the contact time of water with the catalyst. Full article

Hypochlorous acid (HClO) serves as a biological mediator and is widely utilized as a disinfectant in food processing and water treatment. However, excessive HClO residues in food and environmental water raise concerns due to the potential formation of carcinogenic chlorinated byproducts and disinfection byproducts (DBPs). Despite its importance, traditional methods for HClO detection often involve complex sample preparation, sophisticated instrumentation, and skilled operators. Herein, we report an aggregation-induced emission (AIE) small molecule fluorescent probe (NYV) that integrates colorimetric and ratiometric fluorescence responses for the detection of HClO. This probe exhibits high sensitivity, with a detection limit of 0.35 $\mathsf{\mu }$M, a rapid response time of 1 min, and a wide linear range (0–142.5 $\mathsf{\mu }$M), along with anti-interference capabilities, making it suitable for real-time monitoring. Furthermore, we have developed a portable solid-state sensor based on probe NYV for the rapid visual detection of HClO. The potential applications of this probe in real sample analysis and bioimaging experiments are demonstrated. Our findings contribute to the development of innovative fluorescent probes for HClO detection, with broad applications in food safety, environmental monitoring, and biomedical research on oxidative stress and ferroptosis. Full article

This review explores current knowledge on the environmental, oxidative, and genomic effects of sucralose (E955), an artificial sweetener widely used in food products, including those for children, and known to cross both the placental barrier and into breast milk. Although initially considered safe, research conducted over the past two decades has presented conflicting evidence regarding its long-term impact, particularly on ecosystems and biological systems. Structurally similar to chlorinated compounds such as perfluoralkyl substances (PFAS), sucralose is highly persistent in the environment, which complicates its degradation and removal, especially from aquatic systems. Several studies have reported behavioral, metabolic, and even genomic alterations in aquatic organisms exposed to sucralose, raising concerns about its broader ecological safety. In addition, its presence has been linked to shifts in microbiota composition in both environmental and human contexts. Reports of sucralose-induced oxidative stress further highlight the need for caution in its continued use, particularly in sensitive formulations. Given its widespread presence and resistance to degradation, further investigation into the environmental and biological safety of sucralose is urgently needed. Full article

Photodynamic therapy (PDT) is a non-invasive therapeutic method with over a century of medical use, especially in dermatology, ophthalmology, dentistry, and, notably, cancer treatment. With an increasing number of clinical trials, there is growing demand for innovation in PDT. Despite being a promising treatment for cancer and bacterial infections, PDT faces limitations such as poor water solubility of many photosensitizers (PS), limited light penetration, off-target accumulation, and tumor hypoxia. This review focuses on chlorins—well-established macrocyclic PSs known for their strong activity and clinical relevance. We discuss how nanotechnology addresses PDT’s limitations and enhances therapeutic outcomes. Nanocarriers like lipid-based (liposomes, micelles), polymer-based (cellulose, chitosan, silk fibroin, polyethyleneimine, PLGA), and carbon-based ones (graphene oxide, quantum dots, MOFs), and nanospheres are promising platforms that improve chlorin performance and reduce side effects. This review also explores their use in Antimicrobial Photodynamic Therapy (aPDT) against multidrug-resistant bacteria and in oncology. Recent in vivo studies demonstrate encouraging results in preclinical models using nanocarrier-enhanced chlorins, though clinical application remains limited. Full article

This study investigates the formation and toxicity of disinfection by-products (DBPs) arising from the reactions between individual reactive chlorine species (RCS) and dissolved organic matter (DOM) during water treatment. Individual chlorine radicals (Cl^•) and dichloride radicals (Cl₂^•−) were selectively generated with a laser flash photolysis technique, and their interactions with Suwannee River natural organic matter (SRNOM) were analyzed. Results demonstrated a biphasic pattern of DBP formation, where initial increases in RCS exposure enhanced DBP concentrations and toxicities, followed by subsequent decreases at higher RCS exposure. Variations among DBP classes, including trichloromethanes, chloroacetic acids, and chloroacetaldehydes, highlighted the complexity of RCS-DOM interactions. Toxicity assessments further indicated chloroacetonitriles and chloroacetic acids as major toxicity contributors at varying RCS exposures. This study highlights the impact of RCS exposure levels to DBP formation and toxicities, providing mechanistic insights for optimizing parameters in RCS-mediated advanced oxidation processes (AOPs) for safer water treatment. Full article

The hydrolysis oxidation of 1,2-chlorobenzene (1,2-DCB) over Pd-Ti-Ni/ZSM-5(25) catalysts has been investigated as a safe and environmentally friendly method for the removal of chlorinated aromatic organic compounds. Experimental results demonstrate that hydrolysis oxidation technology can effectively suppress the formation of polychlorinated organic compounds. Among the catalysts studied, the 0.5%Pd-2%Ti-8%Ni/ZSM-5(25) catalyst exhibited optimal hydrolysis oxidation performance, achieving complete conversion of 1,2-DCB at 425 °C. Notably, this technology significantly inhibits the formation of polychlorinated organic by-products during the catalytic degradation of 1,2-DCB. Although trace amounts of chlorobenzene were still detected, the overall reduction in hazardous by-products is remarkable. Characterization techniques, including X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), Pyridine adsorption infrared Spectroscopy (pyridine IR) and Fourier transform infrared spectroscopy (FT-IR) analysis, revealed that the acidity and redox properties of the catalyst surface play a pivotal role in the hydrolysis oxidation process. The hydrolysis oxidation of chlorinated volatile organic compounds not only effectively reduces pollutant concentrations but also prevents the generation of more toxic by-products. This dual benefit not only protects the environment but also minimizes ecological risks, highlighting the potential of this technology for sustainable environmental remediation. Full article

In-situ chemical oxidation (ISCO) is a common method to remediate chlorinated ethene contaminants in groundwater. Monitoring the effectiveness of ISCO can be hindered because of insufficient observations to assess oxidant delivery. Advantageously, potassium permanganate, one type of oxidant, provides the opportunity to use its strong electrical signal as a surrogate to track oxidant delivery using time-series borehole geophysical methods, like electromagnetic (EM) induction logging. Here we report a passive ISCO (P-ISCO) experiment, using potassium permanganate cylinders emplaced in boreholes, at a chlorinated ethene contamination site, Naval Air Station Pensacola, Florida. The contaminants are found primarily at the base of a shallow sandy aquifer in contact with an underlying silty-clay confining bed. We used results of the time-series borehole logging collected between 2017 and 2022 in 4 monitoring wells to track oxidant delivery. The EM-induction logs from the monitoring wells showed an increase in EM response primarily along the contact, likely from pooling of the oxidant, during P-ISCO treatment in 2021. Interestingly, concurrent natural gamma-ray (NGR) logging showed a decrease in NGR response at 3 of the 4 wells possibly from the formation of manganese precipitates coating sediments. The coupling of time-series logging and well-chemistry data allowed for an improved assessment of passive ISCO treatment effectiveness. Full article

In chlorination disinfection treatment, residual iodinated X-ray contrast media (ICMs) are the precursors to iodinated disinfection by-products (I-DBPs). This study employed CoFe₂O₄ nanoparticle catalytic peracetic acid oxidation (CoFe₂O₄/PAA) to remove iopamidol (IPM) and control I-DBP formation. The experimental results demonstrated that over 90% of the IPM degradation was achieved in 40 min. The metastable intermediate (≡Co(II)-OO(O)CCH₃), rather than the alkoxyl radicals, was identified as the dominant oxidation species (ROS). The electron transfer pathways between the metastable intermediate and IPM were oxygen-atom transfer and single-electron transfer. The monoiodoacetic acid formation potential (MIAAFP) was investigated. In ultraviolet-activated ClO⁻ (UV/chlorine), a portion of I⁻ generated through IPM dehalogenation underwent conversion to reactive iodine species (RIS), consequently elevating the MIAAFP. In CoFe₂O₄/PAA, the MIAAFP was less than 43% of that in UV/chlorine, which can be attributed to the complete conversion of I⁻ into iodate IO₃⁻ without generating RIS. CoFe₂O₄/PAA is thus a promising treatment for removing ICMs and controlling I-DBP formation due to the efficient degradation of ICMs while avoiding the generation of RIS. Full article

Under China’s “dual carbon” goals (carbon peaking and carbon neutrality), the utilization of high-chlorine coal faces significant challenges due to its abundant reserves in regions such as Xinjiang and its notable environmental impacts. This study systematically investigates the combustion characteristics, environmental risks, and control strategies for high-chlorine coal. Key findings reveal that chlorine release occurs in three distinct stages, namely low-temperature desorption, medium-temperature organic bond cleavage, and high-temperature inorganic decomposition, with release kinetics governed by coal metamorphism and the reaction atmosphere. Chlorine synergistically enhances mercury oxidation through low-activation-energy pathways but exacerbates boiler corrosion via chloride–sulfate interactions. Advanced control technologies—such as water washing, calcium-based sorbents, and integrated pyrolysis–gasification systems—demonstrate substantial emission reductions. However, challenges remain in addressing high-temperature corrosion and optimizing multi-pollutant synergistic control. This study provides critical insights into the clean utilization of high-chlorine coal, supporting sustainable energy transitions. Full article

This paper applies a semi-quantitative approach to review the diversity, environmental controls, detection methods, human health risks, and mitigation of cyanotoxins in drinking water systems (DWSs). It discusses the environmental factors controlling the occurrence of cyanotoxins, presents the merits and limitations of emerging methods of their detection (qPCR, liquid chromatography–mass spectrometry, and electrochemical biosensors), and outlines the human exposure pathways and health outcomes with identification of high-risk groups and settings. High-risk groups include (1) communities relying on untreated drinking water from unsafe, polluted water sources and (2) low-income countries where cyanotoxins are not routinely monitored in DWSs. The fate and behavior processes are discussed, including removing cyanotoxins in DWSs based on conventional and advanced treatment processes. The available methods for cyanotoxin removal presented in this paper include (1) polymer-based adsorbents, (2) coagulation/flocculation, (3) advanced oxidation processes, (4) ultra- and nanofiltration, and (5) multi-soil layer systems. Future research should address (1) detection and fate in storage and conveyance facilities and at the point of consumption, (2) degradation pathways and toxicity of by-products or metabolites, (3) interactive health effects of cyanotoxins with legacy and emerging contaminants, (4) removal by low-cost treatment techniques (e.g., solar disinfection, boiling, bio-sand filtration, and chlorination), (5) quantitative health risk profiling of high-risk groups, and (6) epidemiological studies to link the prevalence of human health outcomes (e.g., cancer) to cyanotoxins in DWSs. Full article

A rapid and accurate evaluation of a chemical disinfectant’s bactericidal efficacy is crucial for ensuring effective infection control, preventing the spread of pathogens, and supporting the development of new disinfectant formulations. In this study, we report a rapid, label-free flow cytometry (FCM) protocol for evaluating the bactericidal efficacy of disinfectants. Five commercial disinfectants (alcohols, oxidizing agents, and alkylating agents) were evaluated against type strains recommended by EN 13727+A2 and ten clinical strains. The label-free FCM method allowed the determination of disinfectant efficacy through assessment of scatter light profiles (FSC-H/SSC-H) and count differences. The label-free FCM provided the results in approximately 4 h and showed strong correlation with standard tests (91.4%, sensitivity 0.94 and specificity 0.98) that can take up to 48 h. Our results represent a proof-of-principle that label-free FCM can reliably assess the efficacy of chemical disinfectants, the same day, and substantially faster than the current growth-based methods. Additionally, the study highlights the potential of the FCM method for detecting the occurrence of viable but non-culturable bacteria following treatment with chlorine-based disinfectants. With its speed, accuracy, and capability to identify bacterial injuries at a single-cell level, the FCM method is a powerful tool for assessing the efficacy of new disinfectant formulations. Full article

Chlorine gas and hydrogen chloride are highly reactive chemicals that pose a significant hazard to living organisms upon direct contact. Also, chlorine-containing gases are often by-products of industrial chemical synthesis and can be released into the air as a result of accidents. This can lead to great pollution of the environment. To remove toxic gases, various filter systems can be used. Filters based on carbon nanomaterials can be suitable for capturing gaseous chlorine-containing substances, preventing their spread into the air. In this work, the sorption activity of various carbon-based nanomaterials (graphene oxide, modified graphene oxide, reduced graphene oxide, multi-walled carbon nanotubes, carbon black) in relation to gaseous chlorine and hydrogen chloride was investigated for the first time. It has been shown that employed carbon nanomaterials have an excellent ability to remove chlorine and hydrogen chloride from the air, exceeding the performance of activated carbon. Modified graphene oxide with an increased surface area showed the highest sorption capacity of 73.1 mL HCl and 200.0 mL Cl₂ per gram of the sorbent, that is almost two and five times, respectively, higher than that of activated carbon. The results show that carbon nanomaterials could potentially be used for industrial filters and membrane fabrication. Full article

In agricultural production, pesticides play an important role in increasing crop yields. However, pesticide residues are caused by improper handling by users during the production process. Chlorine dioxide and ozone, as strong oxidants with similarity in spatial structure, effectively degrade pesticide residues and are widely used in water treatment and the food industry. In order to better understand the mechanism of chlorine dioxide and ozone on pesticides, the properties of chlorine dioxide and ozone are introduced in this review. Herbicides, insecticides, and fungicides were selected for this study, and the influencing factors, kinetics, and degradation pathways of degraded pesticides are presented. The degradation of pesticides by chlorine dioxide follows the second-order kinetic model, reacting with functional groups with high electron density in pesticides by electron transfer. Ozone selectively undergoes electrophilic reactions with pesticides in solution. In addition, when the reaction system is alkaline, ozone accelerates the decomposition to form hydroxyl radicals ($·\mathrm{O}\mathrm{H}$), which react with pesticides. Ozone degradation of pesticides satisfies the pseudo-first-order kinetic model. By comparing the mechanism of pesticide degradation by chlorine dioxide and ozone, this paper provides a theoretical basis for solving the problem of pesticide residues in the food industry and water treatment in the future. Full article

A Yb³⁺-doped BiOI 3D nanosheet array composite was successfully fabricated through a solvothermal deposition strategy on flexible carbon cloth (CC). This composite was subsequently integrated with high-chlorine fly ash (FA) blocks to form the Yb-BiOI/CC/FA hybrid material. Comprehensive characterization was performed using multiple analytical techniques for crystalline phase identification, morphological analysis, valence state, band structure evaluation, and charge carrier separation assessment. Electrochemical measurements were conducted to evaluate the material’s electronic properties. Experimental results demonstrated superior photocatalytic performance under visible light irradiation, with the Yb-BiOI/CC/FA composite achieving 52.87% methylene blue degradation efficiency. The reaction rate constant of this modified nanomaterial was approximately 2.1 times higher than that of pristine BiOI/CC/FA. Radical trapping experiments revealed that superoxide radicals (·O₂⁻) served as the predominant oxidative species. This study presents a dual-benefit strategy for environmental remediation by simultaneously achieving sustainable waste valorization of industrial byproducts (FA) and developing high-efficiency photocatalytic materials. The successful integration of rare-earth metal modification with substrate engineering provides valuable insights for designing advanced photocatalytic systems for pollutant degradation. Full article