Efficiently catalytic ozonation of 2,4-dichlorophenoxyacetic acid by natural ferrihydrite: A pH dependent and surface -OH group involved reaction mechanism.

The heterogeneous catalytic ozonation with natural iron oxides has been proven to be a powerful technology for the removal of recalcitrant organics in water due to the involvement of reactive oxygen species. However, little information can be obtained about the performance of Ferrihydrite in catalytic ozonation especially the relavant reaction mechanism. In this study, Ferrihydrite was synthesized via a simple precipitation method and 2,4-Dichlorophenoxyacetic acid (2,4-D) degradation was used to evaluate its catalytic ozonation performance.

Key role of sulfur in sulfidated zerovalent iron during persulfate activation for the dynamic equilibrium of oxidative radicals including SO and OH.

Surface sulfidation has been widely investigated to effectively enhance the utilization and selectivity of iron electrons for enhanced pollutant reduction. However, there is relatively less knowledge on whether sulfidation facilitates the catalytic oxidation process and the mechanism of enhancement. Therefore, in this study, the role of surface sulfidation in modulating the oxidant decomposition pathway and reactive oxygen species generation was investigated with the sulfidated zerovalent iron (S-ZVI) activated persulfate (PS) system.

Multi-targets detection via combination of multi-stimulus-response engineered bacteria and hydrogel-based separation platform.

Establishing a method similar to ICP-MS that can quantitatively analyze multiple heavy metals simultaneously, conveniently, and in situ is highly anticipated. In this study, we integrated the sensing elements of multiple targets and different fluorescence reporting elements to construct an engineered Escherichia coli. When these targets are present, the engineered bacteria can emit a fluorescent signal at the corresponding wavelength.

A Stable and Sensitive Engineering Bacterial Sensor via Physical Biocontainment and Two-Stage Signal Amplification.

Although engineering bacterial sensors have outstanding advantages in reflecting the actual bioavailability and continuous monitoring of pollutants, the potential escape risk of engineering microorganisms and lower detection sensitivity have always been one of the biggest challenges limiting their wider application. In this study, a core-shell hydrogel bead with functionalized silica as the core and alginate-polyacrylamide as the shell have been developed not only to realize zero escape of engineered bacteria but also to maintain cell activity in harsh environments, such as extremely acidic/alkaline pH, high salt concentration, and strong pressure. Particularly, after combining the selective preconcentration toward pollutants by functionalized core and the positive feedback signal amplification of engineering bacteria, biosensors have realized two-stage signal amplification, significantly improving the detection sensitivity and reducing the detection limit.

A cancer cell nanotherapy method based on GHz film bulk acoustic resonator and nanoscale CaO.

Sonodynamic therapy (SDT) is an emerging cancer treatment method in recent years. However, the ultrasound signal utilized for SDT is usually located at a low-frequency spectrum (<2 MHz), and in the field of SDT research, few studies have focused on the exploration and development of ultrasound frequency. Studies have shown that the GHz-level ultrasound can increase cell membrane permeability and have a negligible effect on cell vitality.

Unravelling the impacts of soluble Mn(III)-NOM on arsenic immobilization by ferrihydrite or goethite under aquifer conditions.

The environmental fate of arsenic (As) relies substantially on its speciation, which occurs frequently coupled to the redox transformation of manganese. While trivalent manganese (Mn(III)), which is known for its high reactivity, is believed to play a role in As mobilization by iron (oxyhydr)oxides in dynamic aquifers, the exact roles and underlying mechanisms are still poorly understood. Using increasingly complex batch experiments that mimick As-affected aquifer conditions in combination with time-resolved characterization, we demonstrate that Mn(III)-NOM complexes play a crucial role in the manganese-mediated immobilization of As(III) by ferrihydrite and goethite.

Different effects of selenium speciation on selenium absorption, selenium transformation and cadmium antagonism in garlic.

Currently, planting selenium-rich crops using inorganic selenium such as selenate and selenite is used to address human selenium deficiency problems. In this paper, besides the above two traditional inorganic selenium speciation, we chose a new organic selenium speciation of potassium selenocyanoacetate to investigate the different effects of selenium speciation on selenium absorption, selenium transformation and cadmium antagonism via foliar application. Plantingexperiments showed that the selenium content of garlic bulbs treated with organic selenium was 1.

Self-acclimation mechanism of pyrite to sulfamethoxazole concentration in terms of degradation behavior and toxicity effects caused by reactive oxygen species.

Pyrite has been extensively tested for oxidizing contaminants via the activation of water molecule or dissolved oxygen, while the changing of oxidation species induced by contaminant's concentration has been largely underestimated. In this study, we revealed a self-acclimation mechanism of pyrite in terms of OH conversion to O during the sulfamethoxazole (SMX) degradation process under oxic conditions. Two reaction stages of SMX degradation by pyrite were observed.

Simultaneous detection of As(III/V), Cr(III/VI), and Fe(II/III) by a sensor array based on the morphology regulation of CeO oxidase.

To develop a convenient method for simultaneous detection of As(III/V), Cr(III/VI), and Fe(II/III), three morphologies of CeO oxidase have been prepared. Based on the difference in oxidase activity and binding ability with substrate TMB of CeOof different morphologies, a 3 (Signal unit) × 6 (Target number) × 5 (Repetition) sensor array was constructed to realize simultaneous detection of six variable valence metal ions As(III/V), Cr(III/VI), and Fe(II/III). The lowest detection limit of the array for metal ions was 1.

Enhancement of the Peroxidase Activity of g-CN with Different Morphologies for Simultaneous Detection of Multiple Antibiotics.

The classes and forms of antibiotics directly determine their ecotoxicity and environmental chemical behavior, and developing a sensor array for simultaneous and in situ detection of antibiotics is highly anticipated. In this study, different morphologies of g-CN with different fluorescence properties and peroxidase activity were prepared by regulating the degree of interlayer stacking and planar connectivity. Subsequently, in order to enhance its enzyme activity and amplify the differences in response signals to different antibiotics, three morphologies of g-CN/MIL-101(Fe) were prepared by in situ growth of equivalent amounts of MIL-101(Fe) on g-CN, respectively.

Simultaneous visual detection of multiple heavy metal ions by a high-throughput fluorescent probe.

To develop simultaneous and in-situ detection techniques towards Cr(VI) and Mn(II), Eu/Tb@CDs with white fluorescence were prepared by a one-step hydrothermal method. With the increase of Cr(VI), all fluorescence channels of Eu/Tb@CDs exhibited obvious quenching, and the detection limit (LOD) was 0.10 μM.

A portable and intelligent logic detector for simultaneous and in-situ detection of Al and fluoride in groundwater.

To develop a convenient and intelligent detector for simultaneous and in-situ detection of Al and F in groundwater, a novel organic probe called RBP has been prepared. With the increase of Al, RBP showed a significant fluorescence enhancement at 588 nm, and the detection limit was 0.130 mg/L.

Colloidal iron species driven enhanced HO decomposition into hydroxyl radicals for efficient removal of methylene blue from water.

Colloids are wide-spread in natural waters and colloid-facilitated transport via adsorption was established as the most important mechanism for the mobilization of aqueous contaminants. This study reports another possible, but reasonable, role of colloids for the contaminants driven by redox reactions. Under the same conditions (pH 6.

Chalcogen Elements in Regulating the Local Electron Density of CuX for an Efficient Heterogeneous Fenton-like Process.

In this work, a novel strategy for Fenton activity improvement of CuX was reported, in which the local electron density of Cu sites was regulated via manipulation of simple chalcogen elements (O, S, and Se). Among them, CuSe catalysts show excellent catalytic activity to activate HO for the complete removal of ofloxacin (10 mg/L) at an initial pH of 6.5 within 120 min.

Boric Acid Functional Fluorescent Covalent-Organic Framework for Sensitive and Selective Visualization of CHHg.

Methylmercury (CHHg) recognition remains a challenging and imperative task due to its high toxicity and wide existence in the ecosystem. Herein, a novel fluorescent covalent-organic framework containing a boric acid functional group (COF-BA) was prepared by a postmodification strategy for CHHg detection. COF-BA served as a sensing platform for CHHg with fluorescence static quenching accompanied by fluorescence color changing from intense blue to colorless, and the detection limit was determined as 1.

Ultra-trace detection and efficient adsorption removal of multiple water-soluble volatile organic compounds by fluorescent sensor array.

Due to the extremely low concentration, complex composition and easy to be converted into each other in water and air of water-soluble volatile organic compounds (VOCs), it is a great challenge to the traditional detection technology, pollution control and traceability, etc. Therefore, developing a convenient, swift and on-site detection method for simultaneous quantification of multiple VOCs is highly anticipated. In this paper, a multifunctional sensor array with adsorption and sensing of VOCs has been constructed by four fluorescence channels of small-sized Eu@Uio-66 and Tb@Uio-66.

New method for morphological identification and simultaneous quantification of multiple tetracyclines by a white fluorescent probe.

The threat of tetracycline antibiotics to the environment and human health is attracting widespread attention. The development of morphological analysis and quantitative techniques of multiple tetracyclines is of great significance for the evaluation of biochemical toxicity, wide-spectrum antibacterial property and degradation cycle between different tetracyclines. In this study, the white fluorescent Eu/Tb@CDs was synthesized and applied successfully to the identification and detection of the most widely used tetracycline antibiotics (tetracycline (TC), oxytetracycline (OC), chlortetracycline (CC) and doxycycline (DC)) with detection limits all below 1 nM.

Film-based fluorescent sensor for visual monitoring and efficient removal of aniline in solutions and gas phase.

Aniline has attracted much concern for its long degradation half-life and huge toxicity to the environment and human beings. Therefore, the development of a multi-functional device for visual detection and efficient removal of aniline was highly anticipated. In our work, the small-size Eu@UiO-66(COOH) was obtained by post-synthesis modification (PSM), and then the film-based fluorescent sensor was prepared by crosslinking reaction.

New Insight into a Fenton-like Reaction Mechanism over Sulfidated β-FeOOH: Key Role of Sulfidation in Efficient Iron(III) Reduction and Sulfate Radical Generation.

Sulfidation can greatly improve the efficiency of utilization of reducing equivalents for contaminant removal; however, whether this method benefits Fenton-like reactions or not and the possible mechanism are not well understood. In this study, we revealed that surface sulfidation can greatly promote the heterogeneous Fenton activity of β-FeOOH (FeS@β-FeOOH) by 40 times, in which not only the OH formation was enhanced but also SO as a new oxidation species was generated. Moreover, their contribution to metronidazole (MTZ) degradation was 52.

Insight into enhanced Fenton-like degradation of antibiotics over CuFeO based nanocomposite: To improve the utilization efficiency of OH/O via minimizing its migration distance.

In Fenton or Fenton-like processes, the key step is to catalyze HO and produce highly reactive OH radicals. More efforts are then focus on designing efficient heterogeneous Fenton catalysts by activating HO to generate OH at the highest possible steady state concentration. In this study, using the antibiotic ofloxacin as target organic pollutant, we firstly demonstrate a point of view for improving OH utilization efficiency by regulating surface chemical reactions to minimizing its migration distance to the target pollutant.

Identification and manipulation of active centers on perovskites to enhance catalysis of peroxymonosulfate for degradation of emerging pollutants in water.

Perovskites (the general formula of ABO) with versatile substrates can serve as desirable catalysts to initiate advanced oxidation processes (AOPs) for environmental remediation. However, the knowledge regarding the active centers remains piecemeal and unclear, such as how the redox metal centers of B site, inert metals of A site, oxygen vacancies, and direct oxidation of catalysts govern the chemical degradation of aqueous pollutants. This study aimed to identify principal alternations in physicochemical and electrical properties of ABO-based perovskites modified with partial/overall substitution at A/B sites and synthesized at different conditions.

Rapid and sensitive screening of multiple polycyclic aromatic hydrocarbons by a reusable fluorescent sensor array.

Simple and rapid sensing of polycyclic aromatic hydrocarbons (PAHs) remains a great technical challenge due to their chemical stability and structural similarity. Here, a simple, sensitive and cost-effective sensing strategy is proposed to detect multiple PAHs by utilizing the inner filter effect (IFE) and a reusable fluorescent sensor array consisting of four polyvinyl alcohol (PVA) composite carbon quantum dots (CDs) film sensors. The CDs/PVA films have a wide and tunable excitation range, which provide sufficient spectral overlap with PAHs and ensure the efficient occurrence of IFE.

Smartphone as a simple device for visual and on-site detection of fluoride in groundwater.

Developing a portable device for visual and on-site detection of fluoride in groundwater is highly anticipated. In this paper, 2-(tert-butyl-diphenylsilanyloxy)-5-nitro-1H-benzoimidazole (1) has been rationally designed via a silanization reaction for self-calibration detection of fluoride, and the detection limit was calculated as 0.11 μM.

Natural alumina/silica suspended particles in water to enhance ofloxacin degradation with UVA-HO driven by surface chemistry.

UV-HO is the most widely used oxidizing system with established effectiveness and a high level of technical development for practical application. However, little attention was paid on the effect of suspended particles in natural water on organic contaminants removal via UV-HO technique. In this study, this effect of suspended particles to enhance the contaminant degradation was explored using silica/alumina-based oxides (MCM-41 and Al@MCM-41) as the representative.

Hydroxyl Radical-Involving -Nitrophenol Oxidation during Its Reduction by Nanoscale Sulfidated Zerovalent Iron under Anaerobic Conditions.

Sulfidated zerovalent iron (S-ZVI) has been extensively used for reducing pollutants. In this study, the oxidation process in the reductive removal of -nitrophenol (PNP) by S-ZVI was confirmed under anaerobic conditions. We revealed that a PNP oxidation process involving OH resulted from the HO activation by surface-bound Fe(II) in S-ZVI, in which HO was generated via a surface-mediated reaction between water and FeS.