Interference Of Ions Research Articles

Luminescent Multifunctional Nanomaterials: Capacitive Removal and Enhanced Detection Efficiency of Heavy Metals Ions for Advanced Water and Wastewater Treatment Application

AbstractIn recent years, heavy metal ions pollution in the industrialized environment of the societies threaten human health that flaunt ill‐sorted blueprints in freshwater resources obviously. The paradigm of designing luminescent multifunctional nanomaterials finds directions to the strategies of synthesizing cost‐effective, green, and versatile nanomaterials not only for detection, but also removal process of heavy metal ions in large scale applications. Among them, discovering the advances of luminescent multifunctional nanomaterials provides broad types of biomaterials, polymers and porous nanoparticles that grabs focal of investigations over the past several years due to their unique advantages such as enhanced detection efficiency with lowest limit of detection (LOD), minimum ions interference in versatile removal process, fast responsivity and selectivity as outstanding as unique physicochemical properties. This review paper tries to highlight the paradigm of principles for design, development, and utilization of luminescence nanomaterials for considering fundamental detection and removal mechanisms of heavy metal ions. In particular, these nanomaterials increase the remediation quality that are tackled in detail by focusing on opportunities and challenges in the field. Finally, design methods of these nanomaterials and concentrating on empowered detection and removal efficiency for heavy metals ions highlights novel prospective and strategies for largescale applications.

Self-supply of hydrogen peroxide by a bimetal-based nanocatalytic platform to enhance chemodynamic therapy for tumor treatment.

The Tumor Microenvironment (TME) is characterized by low pH, hypoxia, and overexpression of glutathione (GSH). Owing to the complexity of tumor pathogenesis and the heterogeneity of the TME, achieving satisfactory efficacy with a single treatment method is difficult, which significantly impedes tumor treatment. In this study, composite nanoparticles of calcium-copper/alginate-hyaluronic acid (CaO2-CuO2@SA/HA NC) with pH and GSH responsiveness were prepared for the first time through a one-step synthesis using hyaluronic acid (HA) as a targeting ligand. Nanoparticles loaded with H2O2 can enhance the ChemoDynamic Therapy (CDT) effects. Simultaneously, Cu2+ can generate oxygen in the TME and alleviate hypoxia in tumor tissue. Cu2+ and H2O2 undergo the Fenton reaction to produce cytotoxic hydroxyl radicals and Ca2+ ions, which enhance the localization and clearance of nanoparticles in tumor cells. Additionally, HA and sodium alginate (SA) were utilized to improve the targeting and biocompatibility of the nanoparticles. FTIR, XRD, DLS, SEM, TEM, and other analytical methods were used to investigate their physical and chemical properties. The results indicate that the CaO2-CuO2@SA/HA NC prepared using a one-step method had a particle size of 220 nm, a narrow particle size distribution, and a uniform morphology. The hydrogen peroxide self-supplied nanodrug delivery system exhibited excellent pH-responsive release performance and glutathione-responsive •OH release ability while also reducing the level of reactive oxide species (ROS) quenching. In vitro cell experiments, no obvious side effects on normal tissues were observed; however, the inhibition rate of malignant tumors HepG2 and DU145 exceeded 50%. The preparation of CaO2-CuO2@SA/HA NC nanoparticles, which can achieve both chemokinetic therapy and ion interference therapy, has demonstrated significant potential for clinical applications in cancer therapy.

A Novel Rhodamine‐Tetraphenylporphyrin Fluorescence Probe for Imaging Mercury In Vitro and In Vivo

ABSTRACTA highly selective fluorescent sensor Por‐RBO for determination of Hg2+ was designed and synthesized with Rhodamine B and Tetraphenylporphyrin. The sensor can determine the Hg2+ of a solution within the pH 5.0–8.0, free from interference of other metal ions. When detected in buffer solution, the fluorescence was the strongest when five times the concentration of Hg2+ ion was added. Calculated by fluorescence titration method, the detection limit of sensor Por‐RBO for Hg2+ ion was as low as 0.12 μmol/L. The geometries of Por‐RBO and Por‐RBO‐Hg2+ were optimized at the B3LYP/6‐31G** level by density functional theory. The charge distribution, orbital interactions, and bonding characteristics were analyzed and compared in detail to discuss the recognition mechanism and structure–fluorescence property relationships. The results of cell fluorescence imaging and CCK‐8 experiments indicate that the sensor Por‐RBO exhibits lower cytotoxicity. Por‐RBO can be used for fluorescence distribution imaging of Hg2+ in living cells.

Ultrafast and Highly Selective Sequestration of Radioactive Barium Ions by a Layered Thiostannate.

As a simulant of hazardous 226Ra2+, the simultaneously selective and rapid elimination of radioactive 133Ba2+ ions from geothermal water is necessary but still challenging. In this paper, we demonstrated the usability of a layered thiostannate with facile synthesis and inexpensive cost, namely, K2xSn4-xS8-x (KTS-3, x = 0.65-1), for the remediation of radioactive 133Ba2+ in multiple conditions, including sorption isotherm, kinetics, and the influences of competitive inorganic/organic ions, pH values, and dosages. KTS-3 has a strong barium uptake ability (171.3 mg/g) and an ultrafast adsorption kinetics (about 2 min). Impressively, it can achieve a high preference for barium regardless of the excessive interference ions (Na+, K+, Mg2+, Ca2+, and humic acid) and acidic/alkaline environments, with the largest distribution coefficient Kd value reaching 6.89 × 105 mL/g. Also, the Ba2+-laden products can be easily eluted by a concentrated KCl solution, and its adsorption performances for barium resist well even after five consecutive cycles. In addition, owing to the regular appearance and excellent mechanical strength, the prepared KTS-3/PAN (PAN = polyacrylonitrile) granule displays a good removal efficiency in the flowing ion-exchange column. These advantages mentioned above render it very promising for the effective and efficient cleanup of radioactive 133Ba2+-contaminated wastewater.

Stratified nanoflower bimetallic cobalt/iron alloy derived from CoFe-MOFs as efficient peroxymonosulfate activator for antibiotics degradation: Performance, mechanism, and toxicity

Co-based metal-organic framework (Co-MOFs) derivative has gained wide attention in the field of advanced oxidative processes (AOPs). However, the degradation efficiency of single cobalt element remains suboptimal and its activation mechanism still needs to be further explored. In this study, stratified nanoflower bimetallic cobalt/iron alloys (CoFe-NC), derived from cobalt/iron bimetallic-organic frameworks (CoFe-MOFs), was synthesized via self-assembly at room temperature, hydrothermal synthesis and high-temperature carbonization processes and their performance as efficient activators of peroxymonosulfate (PMS) for the degradation of antibiotics was evaluated (removal efficiency of 100 % within 40 min, k=0.0951 min−1). The excellent degradation property benefit by specific nano-flowers structure with high specific surface area (424.67 m2/g), the cycle between Co0→Co2+↔ Co3+ and Fe0→Fe2+↔Fe3+, synergistic effect of Co and Fe bimetals. Furthermore, the CoFe-NC/PMS system exhibits exceptionally high cyclic stability (over 85 % degradation efficiency after four times degradation), a wide range of pH (3−11) and resistance to background ion interference (Cl–, H2PO4–, NO3–, HCO3– and HA), and reduced toxicity of the degradation products. Degradation mechanistic studies demonstrated that the activation of PMS by CoFe-NC generated amounts of reactive oxygen species (ROS) (SO4•−, •OH, •O2− and 1O2). Additionally, high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis identified fifteen intermediate degradation products and three possible degradation pathways were proposed. The results highlight the potential of CoFe-NC as a catalyst for antibiotic removal, providing insights into the optimization of bimetallic-organic framework for environmental applications.

Super-Tough, Non-Swelling Zwitterionic Hydrogel Sensor Based on the Hofmeister Effect for Potential Motion Monitoring of Marine Animals.

Hydrogel-based electronic devices in aquatic environments have sparked widespread research interest. Nevertheless, the challenge of developing hydrogel electronics underwater has not been profoundly surmounted because of the fragility and swelling of hydrogels in aquatic environments. In this work, a zwitterionic double network hydrogel comprisedof polyvinyl alcohol (PVA), poly(sulfobetaine methacrylate) (PSBMA), and sulfuric acid (H2SO4) demonstrates super-tough and non-swelling performance. The Hofmeister effect of H2SO4 and PSBMA induces the PVA chains to form numerous nanocrystalline domains, which serve as the primary physical crosslinking points and provide effective energy dissipation. H2SO4 induces a strong salting-out effect to facilitate PVA crystallization and the formation of a dense and stable network structure that inhibits swelling. The resulting hydrogel exhibits an ultra-high toughness of 4.61MJm-3, non-swelling, and long-term stability for up to a month in pure water and seawater. Based on this, a hydrogel-based seawater strain sensor has been developed to monitor the underwater movements of marine animal models. Reliable and stable sensing performance ensures real-time collection of underwater motion signals, despite the impacts of water flow and the interference of ions. This study provides a facile approach to designing super-tough and non-swelling hydrogels and further expands the application of underwater electronic devices.

Advanced nano modification of ecofriendly glauconite clay for high efficiency methylene blue dye adsorption

This research focuses on the utilization of nano glauconite clay as an environmentally friendly sorbent for the removal of cationic dyes, particularly Methylene Blue (MB), from polluted water. The glauconite clay was sourced from the El Gidida region of Egypt and subjected to grinding in a laboratory-type ball mill to ensure homogeneity and increase the active sites available for the adsorption process. The resulting ball milled nano clay (BMNC) was characterized using techniques such as X-ray fluorescence (XRF), Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The concentration of MB dye was monitored using UV–Vis spectroscopy to assess the adsorption capacity of BMNC under various conditions including pH, time, dose, and temperature. The optimal conditions for the adsorption process were determined to be a pH range of 7–8, a contact time of 60 min, and a dose of 200 ppm, resulting in an adsorption capacity of 128 mg/g. This process demonstrated both low cost and high speed. The adsorption mechanism of MB on the BMNC surface was evaluated through kinetics, adsorption isotherms, and thermodynamics. The experimental data indicated an endothermic, spontaneous, and thermodynamically favourable adsorption process, which was further supported by simulated modelling results using Forcite program. The in-silico data aligned well with the experimental findings. Additionally, the study assessed the interference of salts, metal ions, and other dyes on MB adsorption onto BMNC, showing promising results. These findings strongly support the effectiveness of our sorbent substrate under challenging conditions.

Rapid and highly sensitive detection of trace chromium and copper in tea infusion using laser-induced breakdown spectroscopy combined with electrospinning technology

Tea infusion, as one of the most popular beverages, is favored by people around the world. However, tea plants accumulate heavy metals from the soil during growth, which are gradually transferred to the leaves and subsequently decomposed into the tea infusion after soaking in hot water. Long-term consumption of tea infusion containing heavy metals may lead to severe health issues, such as liver dysfunction and cancer. Therefore, rapid, precise, and highly sensitive detection of heavy metals in tea infusion becomes crucial for human health. Traditional methods, such as atomic absorption spectroscopy (AAS), suffer from long detection cycles, high costs, and the risk of secondary pollution from chemical extraction reagents. Thus, this paper presents a method, using laser-induced breakdown spectroscopy combined with electrospinning technology (LIBS-ES), to detect trace amounts of Cr and Cu in tea infusion. The electrospun nanofiber membranes (ENM) were modified with gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs), achieving ultra-sensitive detection of Cr and Cu. The experiment results show that the limits of detection for Cr and Cu are 5 μg/L and 10 μg/L, respectively. Moreover, this method was successfully applied to the detection of Cr and Cu in seven different types of tea infusion, achieving recovery rates of 99 %-106 % and 99 %-108 %, respectively. The method demonstrated good performance even under the interference of other ions at various concentrations, providing a reference for the rapid and highly sensitive detection of heavy metals in tea infusion.

Advanced AIE Materials for Environmental Monitoring: Selective Sensing of Thorium(IV) in Aquatic Systems.

Thorium (Th) is commonly used in various applications, but its long-term exposure poses health risks, necessitating its detection in aqueous environments. Traditional methods such as inductively coupled plasma mass spectrometry are sensitive but require complex instrumentation. Optical sensors, particularly fluorometry-based methods, are simpler, cost-effective, and selective. However, developing effective aggregation-induced emission (AIE) turn-on sensors for Th(IV) requires water-soluble fluorophores with a low background fluorescence. In the present work, we report a turn-on detection method for Th(IV) based on the AIE of the fluorophore tetra(4-sulfophenyl) ethylene (SuTPE). Th(IV)-induced aggregation of SuTPE and the simultaneous drastic enhancement of the emission property of SuTPE have been utilized for the selective sensing of Th(IV) in 100% aqueous media. The sensing mechanism was explored using ground-state absorption, steady-state and time-resolved emission, FTIR, DLS, SEM, AFM and quantum chemical studies of the SuTPE-Th(IV) complex. The selectivity of the present probe toward Th(IV) ions has been established by studying the interference of several metal ions, including lanthanides and uranyl ions. The LOD for Th(IV) was estimated to be 240 nM (56 ppb). The performance of the probe was demonstrated in tap water and diluted seawater matrixes. This work provides a significant advance for Th(IV) detection in aqueous environments, with implications for environmental monitoring and health safety.

A red cell membrane-camouflaged nanoreactor for enhanced starvation/chemodynamic/ion interference therapy for breast cancer

In this study, a multifunctional Cu-doped CaO2 nanoreactor loaded with GOx and camouflaged with a folic acid-modified cell membranewas developed for breast cancer treatment. The as-developed composite nanoreactor showed a synergistic effect on calcium overload to damage mitochondria, thus killing tumor cells to achieve ion interference therapy (IIT). The loaded GOx could deplete glucose to “starve” tumor cells. The H2O2 released by CaO2 decomposition and enzyme catalytic reactions from GOx could not only be highly toxic in the tumor microenvironment but also enhance the efficiency of chemodynamic therapy (CDT) with Cu2+. The red blood cell membranes modified by folic acid achieved a combination of active targeting and passive targeting, thereby enhancing the targeting ability of the as-prepared multifunctional composite nanoreactor and prolonging its retention time at the tumor sites for more than 48 h.

Preparation of composites of lithium-aluminum layered double hydroxides and biochar and their performance in lithium extraction from aqueous media

Layered lithium aluminum double hydroxides (LiAl-LDH) have significant potential for industrial applications, particularly as adsorbents for lithium extraction from salt lakes. However, their development is constrained by a relatively low adsorption capacity. To address this limitation, a composite material comprising biochar (BC) and lithium aluminum layered double hydroxide (LiAl-LDH@BC) was synthesized via a hydrothermal reaction, using Al(NO3)3·9H2O, LiNO3, urea, and varying amounts of BC as raw materials. This composite demonstrates excellent Li+ adsorption capacity (19.6 mg/g). LiAl-LDH@BC2.5 was characterized using SEM, XRD, XPS, and other analytical methods. The effects of various adsorption conditions—including adsorption temperature, initial Li+ concentration, time, pH, ion interference, and the number of cycles—on the Li+ adsorption performance of LiAl-LDH@BC were investigated. The increased specific surface area and the electrostatic adsorption of surface functional groups after composite formation are the primary reasons for the high adsorption capacity. The mechanism of Li+ adsorption follows pseudo-first-order kinetics and the Langmuir model, involving both physical and chemical adsorption. This study offers a promising adsorbent for the extraction of Li+ from aqueous media.

Novel biomass carbon dots/chitosan hydrogel-modified TiO2: An effective reduction of Cr(VI) in various wastewater under sunlight

Hexavalent chromium (Cr(VI)) poses a serious threat to the environment and human health owing to its inherent toxicity. Photocatalysis technology has garnered widespread attention owing to its efficiency and environmental friendliness. However, existing photocatalysts are constrained by light conditions, low reduction rates, and lack of studies in real wastewater. In this study, biomass carbon dots (P-CDs) were synthesized from peanut shell powder, then combined with chitosan (CS) and TiO2 to create a novel photocatalyst (9:1 1 % P-CDs/TiO2@CS). The photocatalyst exhibited a smaller band gap and a broader light absorption range than TiO2, while the porous structure of the hydrogel increased the contact area between P-CDs/TiO2@CS and Cr(VI), thereby enhancing its photocatalytic performance. Our study demonstrates that under simulated sunlight using a xenon lamp, 0.2 g of 9:1 1 % P-CDs/TiO2@CS reduced 50 mg/L Cr(VI) at a rate of 99.64 % in 30 min (pH 7). The photocatalyst also exhibited excellent reduction capabilities for Cr(VI) across a pH range (pH 2–9), at different concentrations (10, 20, 30, 40, 50, and 60 mg/L), and in various real wastewater samples (influent, effluent, and electroplating wastewater). After five cycles, the reduction rate was still maintained at 90.38 %. Experiments conducted under natural sunlight and ion interference further confirmed its outstanding photocatalytic performance and stability in real-world applications. Free radical trapping experiments indicated that electrons (e-) and holes (h+) were the primary active species. Additionally, antibacterial experiments showed that the reactive oxygen species generated by the photocatalyst under light irradiation effectively inhibited the proliferation ofEscherichia coli. Thus, P-CDs/TiO2@CS holds significant potential for practical application in environmental wastewater treatment.

Waste Tea as Absorbent for Removal of Heavy Metal present in Contaminated Water

The goal of this study is to investigate the efficacy of tea-derived absorbents for the removal of heavy metals from contaminated water. For this, absorbents were prepared from milk tea (MT) waste, Ilam tea (IT) waste, and various types of tea leaves, including Immature (IML), mature (ML), and old leaves (OL). The characterization of the absorbents revealed distinct physical and chemical properties from X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), with varying degrees of effectiveness observed across different absorbent types. Heavy metal removal efficiency was assessed using a chemical-free UV-spectrophotometer. The results show that the maximum removal efficiency for Cd using the IT absorbent reaches up to 82.14% with 100 ppm cetyltrim ethylammonium bromide (CTAB), while the minimum removal efficiency is 32.14% using the OL absorbent with 20 ppm CTAB. For Zn, the OL absorbent demonstrates a maximum removal efficiency of 52.59% with 100 ppm CTAB, whereas the minimum efficiency is 3.70% using the ML absorbent with 20 ppm CTAB. For Ni, the highest removal efficiency is achieved with the ML absorbent, reaching up to 97.73% with 100 ppm CTAB, and the lowest is 31.82% with the MT absorbent with 20 ppm CTAB. The addition of a catalyst further enhanced removal efficiencies in both absorbents and metals. Also, the removal of heavy metal ions using 0.05 g of tea absorbent combined with CTAB at varying concentrations. Results show that the addition of 20 ppm and 100 ppm CTAB significantly reduces metal ion concentrations from an initial 100 mg/L. The metal ion concentration decreases as CTAB concentration increases, demonstrating the effectiveness of CTAB in enhancing the absorption capacity of tea absorbent for heavy metal removal. The investigation of selective adsorption of Ni, Zn, and Cd by an adsorbent, revealing competitive adsorption behavior with Ni and Zn being adsorbed more rapidly than Cd, suggesting the impact of metal ion interference on adsorption efficiency. However, limitations were observed with certain absorbent types; for instance, immature leaves did not effectively remove Ni. Overall, this study underscores the potential of tea-derived absorbents as sustainable solutions for mitigating heavy metal pollution in industrial wastewater. Further research is needed to optimize absorbent formulations and explore their applicability in real-world environmental remediation scenarios.

Improving the removal performance of cadmium from wastewater by phosphate-modified sludge biochar: A mineral dissolution-precipitation perspective

To improve the removal performance of sludge biochar (BC) for heavy metal Cd2+ in wastewater, phosphate-modified sludge biochar (PBC) was prepared by impregnation-pyrolysis. Batch removal experiment was conducted to research the impact of initial solution pH, coexisting ions, contact time, reaction temperatures, and Cd2+ concentrations on the adsorption capacity of adsorbent. The outcome indicated that PBC exhibited excellent Cd2+ removal efficiency at pH 5-7. Compared to the original biochar, phosphate-modified biochar had a stronger resistance to ion interference. The models of pseudo-second-order and Langmuir well described the adsorption processes of Cd2+ on BC and PBC. The maximum adsorption capacities of PBC for Cd2+ were 163.93mg/g, significantly higher than that of BC (72.94mg/g). Adsorption mechanism analysis suggested that Cd2+ removal involved complexation, electrostatic attraction, cation-π interactions, and co-precipitation. According to the semi-quantitative analysis of the mechanism, the leading mechanism for Cd2+ removal by PBC was precipitation (79.94%), whereas the primary mechanisms for Cd2+ removal by BC were complexation (42.57%) and precipitation (48.85%). The strategy of converting highly mobile Cd2+ in aqueous solutions into insoluble cadmium phosphate precipitates using phosphate-modified sludge biochar can be an ideal approach for removing Cd2+ from wastewater.

Alginate-based functionalized, remote, light-responsive hydrogel transducer for synergistic mild photo thermoelectric stimulation for tumor therapy.

Photothermal therapy (PTT) is an effective cancer treatment that circumvents the resistance caused by chemotherapy drugs. Conventional PTT has a relatively high temperature, which is better able to kill tumor tissues, but it is also more damaging to normal tissues. Mild PTT avoids these high temperatures, but its corresponding killing ability becomes lower and enhances the heat resistance of cancer cells, causing tumor self-protection and reducing the therapeutic effect of PTT. Here, we reported a new, remotely stimulable, mild-temperature PTT combined with electrical stimulation-induced ionic interference therapy. We introduced MXenes into alginate based thermoresponsive PVA/P(NIPAm-co-SA) hydrogel (PPS) to formulate mechanically reliable hydrogel electrolyte-based supercapacitors as an ion homeostasis perturbator. The artificially controlled duration of near-infrared radiation modulates the PTT cycle temperature, which is controllably maintained at a little under 45 °C to reduce Hsp90 overexpression. Light-induced phase transitions in the hydrogel produce voltages that resemble low-intensity, alternating electric fields. Moreover, chronic piezoelectric stimulation can inhibit cancer cell proliferation by upregulating the expression of genes encoding Kir3.2 inwardly rectifying potassium channels, by interfering with Ca2+ homeostasis, and by affecting mitotic spindle organization during mitosis. In vivo and in vitro antitumor studies on the 4 T1 model suggest that this functionalized, remote, light-responsive transducer is an effective and promising tool for the treatment of tumors.

Engineered nanozyme-cascade catalyzed reaction for rapid acid phosphatase detection

The utilization of artificial multienzyme-catalyzed cascade reactions have greatly benefited biosensors. This study presents a novel nanoreactor consisting of manganese ions-doped hollow carbon nanospheres (Mn@HCNs), which can rapidly transform molecular information into an easily comprehensible colorimetric signal. The Mn@HCNs nanoreactor was utilized to detect acid phosphatase (ACP) within a range of 0.5–10 mU/mL, achieving a limit of detection (LOD) as low as 0.0851 mU/mL. The superiority of our nanoreactor over traditional ACP detection methods stems from its exceptional substrate affinity and the multi-enzymatic behaviors of Mn@HCNs. Especially, the specific POD-like activity (SA) value of Mn@HCNs was superior to most reported Fe3O4 and other single-atom enzymes. Furthermore, this nanoreactor exhibited exceptional selectivity against protein and ion interference, and was furthered to detect ACP in clinical serum samples. The work may extend the development of artificial multienzyme-catalyzed cascade reactions for molecular biosensors and clinical application.

Simultaneous measurement of labile U(VI) concentration and (234U/238U) activity ratio using a Monophos®-based Diffusive Gradients in thin-films sampler

BackgroundIn a context of environmental monitoring around installations related to the nuclear fuel cycle, the Diffusive Gradient in Thin-films (DGT) technique captures the integrated concentration of U isotopes in their native environment, yielding comprehensive data on U origin (anthropogenic vs natural), total concentration, and mobility. However, for common deployment times (4–5 days) in moderately basic waters, none of the commercially available binding gels is adapted to measure the total U concentration. So, the development of novel DGT binding gels is timely. ResultsA new DGT sampler, using the Monophos® resin, as well as a new model for the interpretation of the DGT flux, has been successfully developed to measure the labile U concentration (which was also its total concentration) in moderately basic waters (pH ≈ 8). The model accounts for the penetration of uranyl carbonate complexes into the binding gel. Monophos-DGT samplers were able to quantify the total U concentration (accuracy >90 %) in three different mineral basic waters and in a synthetic seawater in laboratory experiments, as well as in situ in the rivers Essonne and Œuf, France. Ion interferences (e.g., Ca2+, Mg2+ and HCO3−), critical when using Chelex and Metsorb resins as binding agents, were overcome by using the new DGT sampler, thus allowing for a longer linear accumulation of U in the tested matrices and, above all, a better detection of U minor isotopes improving the potential of using DGT samplers for water source tracing through isotopic measurements. SignificanceThe use of the new DGT sampler and the new model for the interpretation of DGT flux is recommended to improve the accuracy of total U concentration determinations in field applications. Moreover, simultaneous elemental and isotopic measurements were successfully performed during field application, confirming new perspectives for environmental applications such as identification of U pollution sources by using isotopic signatures.

A highly sensitive fluorescent probe based on functionalised ionic liquids for timely detection of trace Hg2+ and CH3Hg+ in food

A novel fluorescent probe was fabricated using fluorescein-based ionic liquids (ILs) to effectively achieve rapid and accurate detection of Hg2+ and CH3Hg+ in food. A probe developed by addition of modified fluorescein into the functionalised ILs presented a promising sensitivity toward Hg2+ and CH3Hg+ at concentrations of 0.4 and 60 nM, respectively. In addition, the novel probe could achieve visual and timely detection of Hg2+ and CH3Hg+ by the naked eyes at concentrations of 0.1 and 1 μM, respectively. The probe could also overcome the interference of potential ions and common organic ligands and detect Hg2+ and CH3Hg+ in real food samples, such as green tea and liquor. The probe could be converted into a paper-based sensor to visually detect Hg2+ and CH3Hg+ at levels as low as 10 nM.

Insights into performance and mechanism of CuCo2O4/MXene composite as an efficient peroxymonosulfate activator for p-nitrophenol degradation

The slow redox cycle during oxidation and the toxicity risk due to leaching of metal ions greatly hinder the practical application of transition metal-based catalysts in advanced oxidation processes. In this study, a novel layered-structured CuCo2O4/MXene composite was prepared by self-assembling CuCo2O4 spinel with two-dimensional MXene and used as a heterogeneous catalyst based on peroxymonosulfate (PMS) activation for the oxidative degradation of p-nitrophenol (4-NP). Benefiting from its unique structure, the degradation efficiency of 4-NP by CuCo2O4/MXene-activated PMS was close to 100 % within 10 min at the initial pH 7.0. Quenching experiments and electron paramagnetic resonance demonstrated that both radical (SO4•- and •OH) and non-radical (1O2) pathways were involved in the degradation of 4-NP. X-ray photoelectron spectroscopy analysis showed that the introduction of MXene could significantly promote the efficient redox cycling of Cu2+/Cu+ and Co3+/Co2+ on the catalyst surface, thus providing a continuous driving force for the PMS activation. More importantly, CuCo2O4/MXene exhibited good ionic interference resistance, high stability and low metal ion leaching rate, suggesting its potential practical application. This work not only demonstrates that CuCo2O4/MXene is a promising catalyst for the degradation of organic pollutants by PMS activation, but also provides a new idea for the development of efficient PMS-activated catalysts for pollutant degradation.

Efficient generation of singlet oxygen (1O2) by CoP/Ni2P@NF for degradation of sulfamerazine through a heterogeneous electro-Fenton process at circumneutral pH

In electro-Fenton (EF), the development of a catalytic material with wide pH application range and high interference resistance is more suitable for practical wastewater treatment. In this study, the nanoneedle-shaped CoP/Ni2P heterostructure loaded onto a nickel foam substrate (CoP/Ni2P@NF) was successfully fabricated, which was used as a cathode material for heterogeneous electro-Fenton (Hetero-EF) to degrade sulfamerazine (SMR) at circumneutral pH. The SMR degradation efficiency within 90 min went to 100% and 87% at initial pH of 6.8 and 11, respectively. Experiments and theoretical calculations demonstrated that the heterostructure of CoP/Ni2P redistributed the interfacial charge and accelerated the electron transfer, resulting in different two-electron oxygen reduction (2e−ORR) selectivity and activity than CoP and Ni2P. The ion interference and complex water quality experiment exhibited that the degradation performance remained almost unchanged, showing better anti-interference ability and complex water quality applications. Through quenching experiments and EPR tests, it is confirmed that singlet oxygen (1O2) was the major reactive oxygen species (ROS) and 1O2 was converted from hydroxyl radical (·OH) adsorbed on the catalyst surface. This study provides an efficient catalyst for the application of Hetero-EF to remove organic compounds in complex water at circumneutral pH.