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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. In the presence of Mn(II), only the fluorescence from Tb and Eu was quenched, while the fluorescence of CDs was not effected. The LOD for Mn(II) was 0.16 μM. More importantly, in the actual water samples where Cr(VI) and Mn(II) coexist, Eu/Tb@CDs can realize their rapid and simultaneous detection by simple spectral calculation. The selective and competitive experiments have also confirmed that the detection of Cr(VI) and Mn(II) was not interfered by common pollutants in groundwater. It is undeniable that the simultaneous detection of multiple targets by one probe not only greatly improves the detection efficiency, but also has important significance for the field monitoring of water quality parameters. [ABSTRACT FROM AUTHOR]

Abstract Portable, rapid, accurate and on-site detection of analysis target has always been the goal of continuous efforts in the field of analysis. In this work, a novel intelligent and rapid detection system based on an AIE dye (TPA-DCV) was established for portable and on-site detection of trace water in organic solvents and CN− in water by integrating the smartphone and linear discriminant analysis (LDA). The TPA-DCV displayed remarkable solvatochromism effect and showed different fluorescence colors to different water contents of different solvents, with the minimum detection limit of 54 ppm. In addition, TPA-DCV also exhibited specific response to CN−, and showed significant fluorescence changes to different amounts of CN−. With the assist of this detection system, these different fluorescence color signals could be accurately classified in canonical score plot. What's more, the classification and distribution of fluorescence color in canonical score plot showed regular change with the target concentration, which could be used to quantify the trace water and CN−. The rationality and practicability of this detection system were preliminary verified by a large number of real sample analyses. This detection system greatly simplifies the analysis process, which is in the proof of intelligent and rapid detection just using a simple color analysis without any instrument test, which may be a big step forward. Graphical abstract Image 1 Highlights • An AIE dye TPA-DCV that exhibits both AIE and solvatochromic effects has been synthesized. • A smartphone and LDA integrated rapid detection system for trace water and CN- is established. • The trace water and CN- can be rapid and intelligent detected without any instrument testing. [ABSTRACT FROM AUTHOR]

To develop a convenient and intelligent detector for simultaneous and in-situ detection of Al3+ and F- in groundwater, a novel organic probe called RBP has been prepared. With the increase of Al3+, RBP showed a significant fluorescence enhancement at 588 nm, and the detection limit was 0.130 mg/L. After combining with fluorescent internal standard CDs, the fluorescence of RBP-Al-CDs at 588 nm was quenched due to the replace of F- for Al3+, while the CDs at 460 nm remained unchanged, and the detection limit was 0.0186 mg/L. For convenient and intelligent detection, an RBP-based logic detector has been developed for simultaneous detection of Al3+ and F-. Within the ultra-trace, low concentration, and high concentration range of Al3+ and F-, the logic detector can achieve rapid feedback on their concentration levels ("U", "L" and "H") through different output modes of the signal lamps. The development of logical detector is of great significance for studying the in-situ chemical behavior of Al3+ and F- and for daily household detection. [Display omitted] • Organic probe of RBP with spiral lactam structure has been designed. • RBP can be used to simultaneously detect Al3 + and F-. • Logic detector based on RBP was designed for intelligent detection of Al3 + and F-. • The detection limits for Al3 + and F- were 0.130 mg/L and 0.0186 mg/L, respectively. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Key factor determining perovskite in PMS activation was firstly investigated. • OFX degradation efficiency decreased with the order of LaNiO 3 > LaMnO 3 > LaFeO 3. • Oxygen defect decreased with the same order of LaNiO 3 > LaMnO 3 > LaFeO 3. • Amount of surface oxygen defect plays a key role in PMS activation over LaBO 3. • Evolution of 1O 2 from PMS over LaBO 3 was proposed by reducing activation barrier. Abstract Recently, perovskite is becoming a promising alternative as peroxymonosulfate (PMS) activator for the remediation of organic pollutants in water. But the factor determining PMS activation efficiency of perovskite and the evolution of reactive oxygen species (ROS) remain equivocal and elusive. In this study, we proposed an oxygen defect dependent PMS activation mechanism over perovskite with the singlet oxygen (1O 2) as the dominant ROS. Among the tested four perovskites, ofloxacin (OFX) degradation efficiency increased with the following order: LaFeO 3 < LaZnO 3 < LaMnO 3 < LaNiO 3 , which agreed well with their oxygen defect amounts based on X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) analysis. The results clearly demonstrated a good relationship among oxygen defects in LaBO 3 , OFX degradation efficiency and 1O 2 concentration. Moreover, 1O 2 evolution mechanism over perovskite by decreasing the activation energy of PMS self-decomposition was proposed. The 1O 2 mediated OFX degradation pathway was further studied by HPLC-MS technique and three-dimensional excitation–emission matrix fluorescence spectroscopy (3D EEMs). This work provides a new insight into PMS activation by perovskites and favors its application in actual water treatment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • BioMnO x had an unprecedented PMS activation efficiency, 3-fold faster than 3D α-Mn 2 O 3. • 100% phenol at 40 min and 99.4% TC at 60 min were degraded in BioMnO x /PMS system. • BioMnO x had a wide pH working range 3.0–9.0 and excellent long-term stability. • 1O 2 was the dominant reactive oxygen species for pollutant degradation over BioMnO x. • Different TC degradation pathway by 1O 2 was proposed vs. by OH radical. Abstract From the view of environment and easy availability, to develop the most efficient manganese oxide for peroxymonosulfate (PMS) activation is of great importance for the degradation of recalcitrant organic pollutants. In this study, biogenic manganese oxide (BioMnO x) exhibited an unprecedented efficiency than the most efficient 3D α-Mn 2 O 3 prepared by chemical method. 100% of phenol degradation at 40 min and 99.4% of tetracycline removal at 60 min were achieved over BioMnO x with PMS, which was 3-fold faster than 3D α-Mn 2 O 3. BioMnO x also has an excellent long-term stability and good performance toward the pollutants degradation at a wide pH range of 3.0–9.0. Most importantly, 1O 2 was identified as the primary reactive species in BioMnO x /PMS system based on the trapping experiment and EPR analysis. The PMS activation over BioMnO x should follow a self-decomposition and energy quenching mechanism instead of electron transfer process as confirmed by the XPS analysis. Finally, the degradation pathways of tetracycline and phenol by 1O 2 over BioMnO x were proposed according to HPLC and HPLC-MS results, which are greatly different from that by OH oxidation in the literature. [ABSTRACT FROM AUTHOR]

Highlights • In-situ Cu(II) doped in framework of mesoporous MnO 2 , Cu-MnO 2 was prepared. • Cu-MnO 2 had good catalytic activity and stability for phenol degradation by PMS. • Exposed surface oxygen defect was responsible to the enhancement of PMS activation. Abstract Cu(II) doped mesoporous MnO 2 (Cu-MnO 2) was prepared to establish an intimate functional link between the structure substitution and catalytic peroxymonosulfate (PMS) activation. Based on the characterization of powder X-ray diffraction (XRD), N 2 adsorption-desorption measurement, scanning electron microscope (FE-SEM) and transmission electron microscope (TEM), Cu-MnO 2 had a typical long range ordered mesoporous structure and Cu was successfully introduced in octahedral framework. It exhibited excellent catalytic activity and stability for the phenol degradation by PMS. Phenol was always efficiently degraded over Cu-MnO 2 at a pH range of 3.5–9.0. For example, the reaction rate constant at pH 7.0 was 0.073 min−1, which was two times higher than that of MnO 2 (0.039 min−1). Importantly, 1O 2 was identified as the primary reactive species in Cu-MnO 2 /PMS system. X-ray photoelectron spectroscopy (XPS) confirmed that more exposed surface oxygen defects due to Cu doping were responsible to the enhancement of PMS activation for phenol degradation. The results of PMS decomposition and oxygen evolution indicated that surface oxygen defects lower the reaction energy barrier of PMS decomposition by generating 1O 2 via the energy trapping by oxygen. Finally, the heterogeneous PMS activation mechanism over Cu-MnO 2 was proposed. [ABSTRACT FROM AUTHOR]

Sensitive detection and determination of hardness and fluoride in the ground water is an important issue for the water safety. The present work reports a sensitive, selective, rapid and visual hybrid fluorescent nanosensor by hybridizing carbon dots and hexametaphosphate capped gold nanoparticles through intrinsic interactions of the two components. The hybrid nanosensor can be used for hardness (Ca 2+ , Mg 2+ ) detection with the fluorescence intensity decreasing at 439 nm and increasing at 608 nm via the aggregation induced fluorescence resonance energy transfer on mechanism. In addition, the hybrid nanosensor mixed with calcium ions can detect fluoride in water with a lower detection limit of 0.339 ppm with the fluorescence color recovery based on the precipitation induced fluorescence resonance energy transfer off process. Experimental results indicate that the as-synthesized hybrid nanosensor has shown efficient feasibility and practicality for hardness and fluoride detection in actual groundwater samples. Furthermore, a paper-based analytical device has been fabricated by immobilizing the hybrid nanosensor on the cellulose filter paper for the visual and on-site detection of fluoride in water. The hybrid nanosensor would provide new sensing materials and mechanisms for the determination and detection of hardness and fluoride in the groundwater. [ABSTRACT FROM AUTHOR]

Detection of pesticides in ground water has become a very important and crucial research area due to the rapid expansion of agriculture and stringent environmental protection acts. In this paper, the as-prepared CuO-TiO 2 hybrid nanocomposites were decorated on the glass carbon electrode as the nonenzymatic electrochemical nanosensor for the sensitive and selective detection of methyl parathion. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry, showing that the modified electrode can be used for methyl parathion detection. Differential pulse voltammetry was applied to evaluate methyl parathion detection ability under optimized experimental conditions, and found the modified electrode can detect methyl parathion sensitively in a wide dynamic detection range from 0 ppb to 2000 ppb with a lower limit of detection (LOD) of 1.21 ppb. In addition, other interfering materials have no any influences on the detection of methyl parathion. Furthermore, the modified electrode has also been used for methyl parathion detection in the actual ground water samples, and showed efficient sensing ability. The electrochemical sensor developed would have great potentiality for methyl parathion sensing and provide new insights into the detection of other organophosphorous pesticides in the ground water. [ABSTRACT FROM AUTHOR]

The structure and morphology have been proven to be the key parameters determining the catalyst’s activity in peroxymonosulfate (PMS) activation. In this study, the dandelion-like NiCo 2 O 4 microspheres with a mesoporous structure were successfully prepared by a simple hydrothermal method based on the characterization of XRD, BET, FT-IR and XPS analysis. The formation mechanism of dandelion-like microsphere was also proposed based on the results of SEM images at different hydrothermal reaction time. Their performance in PMS activation was evaluated by the humic acid (HA) degradation. It indicated that NiCo 2 O 4 had an excellent catalytic oxidation activity and stability in removing of HA coupled with PMS and the analysis of UV–vis, Fluorescence EEMs and FTIR spectra showed that the original structure of HA was destroyed efficiently. The effect of Ni/Co ratios on catalytic activity for HA degradation was further investigated, in which NiCo 2 O 4 was proven to be the most efficient toward HA degradation (90% at 120 min vs. 50% for Co 3 O 4 under the same conditions). Finally, the possible reaction mechanism was discussed, in which 1 O 2 , SO 4 − and OH, especially 1 O 2 as the dominant active oxygen species were identified and involved the catalytic process. Hence, PMS oxidation over NiCo 2 O 4 provides a promising alternative for HA degradation due to its efficient catalytic activity. [ABSTRACT FROM AUTHOR]

To develop an efficient heterogeneous Fenton catalyst over a wide pH range without any external energy input is still a challenging work. In this study, the Fenton activity of mesoporous iron oxide was firstly extended to pH of 3.6–10.0 by the carbon quantum dots (CQDs) and Cu modification (CQDs/Cu-MIO). The characterization studies indicated that CQDs/Cu-MIO had a typical mesoporous structure and CQDs was highly dispersed on the surface of catalyst. While Cu element with Cu (I) and Cu (II) was introduced in the framework of iron oxide by chemical binding of Fe O Cu. Without the aids of UV, CQDs/Cu-MIO exhibited an excellent efficiency and the ofloxacin (OFX) degradation followed the pseudo-first order kinetic model with a reaction constant of 0.1109 min −1 . Moreover, the catalyst can be reused for 6 times with good stability, in which the maximum concentration of leaching Fe and Cu ions were 0.085 and 0.015 mmol/L. The optimum reaction condition was evaluated and the degradation process of OFX was further investigated by FT-IR spectrum. The reactive oxygen species involved in OFX degradation, the effects of mesoporous structure, Cu/Fe multivalent state and the excellent capability of electron transformation/energy exchange of CQDs on the enhancement of CQDs/Cu-MIO Fenton activity were also discussed. Finally, the heterogeneous Fenton reaction mechanism was proposed based on the experimental results. [ABSTRACT FROM AUTHOR]

To develop an ultraefficient and reusable heterogeneous Fenton-like catalyst at a wide working pH range is a great challenge for its application in practical water treatment. We report an oxygen vacancy promoted heterogeneous Fenton-like reaction mechanism and an unprecedented of loxacin (OFX) degradation efficiency of Cu doped Fe304@FeOOH magnetic nanocomposite. Without the aid of external energy, OFX was always completely removed within 30 min at pH 3.2-9.0. Compared with Fe304@ FeOOH, the pseudo-fust-order reaction constant was enhanced by 10 times due to Cu substitution (9.04/h vs 0.94/h). Based on the X-ray photoelectron spectroscopy (XPS), Raman analysis, and the investigation of 11201 decomposition, 'OH generation, pH effect on OFX removal and H2Or utilization efficiency, the new formed oxygen vacancy from in situ Fe substitution by Cu rather than promoted Fe3+/Fe2' cycle was responsible for the ultraefficiency of Cu doped Fe304@FeOOH at neutral and even alkaline pHs. Moreover, the catalyst had an excellent long-term stability and could be easily recovered by magnetic separation, which would not cause secondary pollution to treated water. [ABSTRACT FROM AUTHOR]

Copper is a highly toxic environmental pollutant in the environmental, biological and chemical fields. Therefore, sensitive, selective and visual detection of Cu 2+ is very important for human health and practical applications. Herein, a novel hybrid ratiometric fluorescent nanosensor was developed for rapid and on-site visualization of Cu 2+ on the basis of integrating benzothiazole fluorophore (MDBT) and red-emissive quantum dots (QDs) embedded in silica nanospheres. Such hybrid ratiometric fluorescent nanosensor exhibits dual emissions at 420 and 640 nm under a single excitation wavelength. Due to the ions promoted oxidation reaction of Cu 2+ towards MDBT, the fluorescence of MDBT can be selectively enhanced. Although the embedded QDs are insensitive to the analyte, variations of the dual emission intensity ratios display continuous colour changes from red to blue. The ratiometric fluorescent approach shows high sensitivity and selectivity towards Cu 2+ against other interfering metal ions. The detection limit of Cu 2+ for the hybrid ratiometric fluorescent nanosensor is determined to be 41.71 nM, which is much lower than the allowable level of Cu 2+ (∼20 μM) in drinking water set by U.S. Environmental Protection Agency. Furthermore, this kind of novel nanosensor can also be applied for Cu 2+ detection in actual water samples and exhibits excellent detection ability. This hybrid ratiometric fluorescent nanosensor is simple, fully self-contained and thus potentially attractive for visual identification without the need of elaborate equipments. [ABSTRACT FROM AUTHOR]

To improve both the activity and stability of electrocatalyst in hydrogen evolution reaction (HER) remains a challenge. In this work, a facile and friendly way to synthesis of CoSe 2 hollow microspheres was reported by using organic selenium source. The growth mechanism of CoSe 2 hollow microspheres attributed to the Kirkendall effect with the hydrothermal reaction time is studied. This CoSe 2 hollow structure with high surface roughness makes this material to expose more active sites, bringing good HER activity with a small tafel slope of 55 mV·dec −1 . Besides, the HER activity of CoSe 2 was greatly improved via the introduction of graphene (CoSe 2 @G) without changing its hollow structure. The superior HER activity of CoSe 2 @G with a lower tafel slope of 42 mV·dec −1 was attributed to the crucial structural-functional coupling effects. Moreover, both CoSe 2 and CoSe 2 @G nanocomposites exhibit high durability and stability, which may provide promising applications in the fields of catalysis, optics, electronics and sensors due to its unique structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • H 2 O 2 occurrence modes (CMH-S/M/L) are successfully constructed. • CMH-L led to a superior OFX degradation efficiency of 93% • Mechanism dominated by •OH or O 2 is altered by H 2 O 2 occurrence modes. • CMH-L with shortest O-H bond (0.988, 1.022Å) cause H 2 O 2 to convert into •OH. • CMH-S with longest O-H bond (1.021, 1.612Å) cause H 2 O 2 to decompose into O 2. Most researches focus on design and optimization of heterogeneous Fenton catalyst itself to drive H 2 O 2 decomposition into •OH radicals. In this study, we reported the significant impact of the interaction mode of H 2 O 2 and CuMnO 2 (namely H 2 O 2 occurrence form) on the Fenton-like performance. The interaction mode of H 2 O 2 largely exposed to Cu atom active site (CMH-L) led to a superior ofloxacin (OFX) degradation efficiency of 93% compared with H 2 O 2 middle exposed around the Cu atoms (CMH-M, 84%) and small part exposed around the Cu atoms (CMH-S, 50%). The effect of H 2 O 2 occurrence forms on catalytic activity were confirmed by analyzing their fraction and the relevant rate constant with the correlation was 98%. And the relevant interfacial reaction mechanism was detailed explored based on density functional theory calculation, a series of probe experiments and quantitative analysis of H 2 O 2 utilization efficiency and •OH generation. It revealed that Cu atom arrangement on CuMnO 2 can induce the different H 2 O 2 occurrence form, and compared with CMH-M especially CMH-S (1.486 and 1.591 Å), CMH-L has the shortest elongation of O-O bond (1.477 vs. 1.468 Å in free H 2 O 2) together with the smallest O-H 1 and O-H 2 (0.988, 1.022 Å), which were more likely to decomposition H 2 O 2 into •OH, while it was more likely to inefficient transformation H 2 O 2 into O 2 in CMH-S system. Thus, this work provided a new insight for improving the heterogeneous Fenton catalytic performance via altering the interaction mode of H 2 O 2 and catalyst, which should be the fundamental reason for efficient H 2 O 2 activation into O 2 or •OH. [ABSTRACT FROM AUTHOR]

This study proposed a new and previously unconsidered reaction mechanism in the activation of peroxymonosulfate. We report that singlet oxygen (1O2) rather than ṖOH or SO4Ṗ− was the dominant reactive oxygen species towards the efficient degradation of ofloxacin and phenol, demonstrating a promising application in real wastewater treatment. [ABSTRACT FROM AUTHOR]

Glucose concentration in human body is a significant indicative for diabetes screening, so it is very significant to develop rapid and sensitive methods for glucose detection. Herein, CoSe 2 /reduced graphene oxide (CoSe 2 /rGO) nanohybrids were synthesized via a simple and convenient hydrothermal method, and also their morphologies and compositions were systematically characterized. The CoSe 2 /rGO nanohybrids were found to possess an intrinsic peroxidase-like activity and can effectively catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H 2 O 2 ) accompanied with a blue color change. The catalytic activity of CoSe 2 /rGO nanohybrids is matched with the typical Michaelis–Menten kinetics and highly dependent on reaction time, pH, incubation temperature, and H 2 O 2 concentration. The peroxidase-like CoSe 2 /rGO nanohybrids were successfully applied for the detection of H 2 O 2 and glucose with the detection limit as low as 0.23 μM and 0.553 μM, respectively. Furthermore, some other carbohydrates, such as lactose, sucrose, galactose and fructose have no interferences with the detection of glucose. The detection platforms for glucose developed in the present work not only confirmed that the CoSe 2 /rGO nanohybrids possess intrinsic peroxidase-like activity but also showed great potential applications in varieties of simple, robust, and easy-to-make analytical approaches in the future. [ABSTRACT FROM AUTHOR]

Nowadays, selective, sensitive and visual detection of 2,4,6-trinitrotoluene (TNT) explosives residues in groundwater system has been a great challenge for human security. Herein, a visual fluorescence paper sensor for accurate and on-site detection of TNT in groundwater system by linking the recognition molecule onto the surface of the carbon quantum dots (CDs) was introduced. The fluorescence of CDs based nanosensor can be selectively and efficiently quenched by TNT through a photo-induced electron transfer effect between primary amino groups and TNT explosives. The fluorescence quantum yield of this kind of nanosensor is up to 32.25％ and the detection limit reaches as low as 0.213 μmol/L. The interference molecules, such as the nitrobenzene derivatives have no influence on the sensitive detection of TNT. Furthermore, the paper sensor based on the CDs probe has been prepared, which can efficiently detect TNT residues in groundwater system. This developed nanosensor possesses the great capability of on-site and visual detection of TNT residues in groundwater without any further processing step. [ABSTRACT FROM AUTHOR]

A novel ratiometric fluorescence sensor for rapid and on-site visual detection of Cu 2+ was designed and synthesized by integrating yellow-emission rhodamine fluorophore (RL) and red-emission CdTe@SiO 2 QDs. The as-prepared nanohybrid fluorescence sensor shows dual-emissions at 537 nm and 654 nm under a single excitation at 500 nm in the presence of Cu 2+ . Owing to the strong chelating ability of RL toward Cu 2+ , the yellow fluorescence of RL could be selectively enhanced while the red fluorescence of CdTe QDs is almost unchanged, leading to an obvious fluorescence color change from red to yellow, which could be used for visual and ratiometric detection of Cu 2+ . This nanohybrid sensor exhibits excellent selectivity, sensitivity and anti-interference to Cu 2+ detection and the detection limit is as low as 8.4 nM. Additionally, a simple device test strip for rapid and on-site detection of Cu 2+ has been designed by immobilizing the RL-CdTe@SiO 2 QDs on a common filter paper. This simple and effective paper-based sensor has a visual detection limit of 0.5 μM, showing its promising application for on-site and rapid sensing of Cu 2+ in pollution water. [ABSTRACT FROM AUTHOR]

The highly dispersed iron layered double hydroxide (Fe-LDH) nanoplates supported on sepiolite (SEP) nanofibers have been successfully prepared via in situ co-precipitation of an iron salt precursor. The as-obtained hierarchical dendrite-like Fe-LDH/SEPs possess high specific area, and exhibit excellent removal ability for arsenic, demonstrating promising potential in environment applications. [ABSTRACT FROM AUTHOR]

The instant and on-site detection of selenium still remains a challenge for environmental monitoring and medical prevention. We herein developed a ratiometric fluorescent nanosensor for accurate and on-site sensing of SeO32− by linking the recognition molecule 3,3′-diaminobenzidine (DAB) onto the surface of carboxyl group modified CdTe@SiO2. The fluorescence of DAB on the surface of silica nanospheres could be selectively and efficiently enhanced by SeO32− through a surface chelating reaction between DAB and SeO32−. Thus, in the presence of SeO32−, the nanosensor would show two characteristic fluorescence emissions of Se-DAB and CdTe QDs under a single excitation wavelength. The selectivity and the optimal conditions for the detection of SeO32− were carefully investigated. The ratio of F530/F635 linearly increased with increasing SeO32− concentration in the range of 0 to 2.5 μM and the detection limit reaches as low as 6.68 nM (0.53 ppb). This developed nanosensor has the capability of on-site detection in an aqueous system without any separation step. The Se concentrations in selenium-rich food were detected and the results were consistent with the values determined by ICP-AES. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multifunctional CuMnO 2 /CeO 2 catalyst is successfully constructed. • CuMnO 2 /CeO 2 led to a superior OFX degradation efficiency of 96% • Catalytic activity is altered by interfacial interaction. • Interfacial enrichment and enhanced electron transfer promoted the whole activity. As a radical predominant reaction, how to enhance the generation and utilization efficiency of radical through interface regulation then to improve its catalytic activity has been the long-term goal to promote its practical application. Realized the redox carrier may play multifunctional roles in catalytic reaction, CeO 2 supported CuMnO 2 (CuMnO 2 /CeO 2) was successful constructed and the catalytic performance, reaction process and the relevant mechanism were compared with its simple physical mixed form (CuMnO 2 + CeO 2). It was found that the introduction of CeO 2 provided a large specific surface area to strengthen the enrichment of pollutants at the interface (10 % vs 5 % for ofloxacin and 32 % vs 27 % for tetracycline hydrochloride). In addition, the activated CeO 2 support enhanced the interfacial electron transfer process and promoted the generation of more highly active Ce3+ in CuMnO 2 /CeO 2. Their synergistic effects shortened the migration distance from the formed radicals to target pollutants, thus improving the generation and utilization efficiency of radicals. So, the ofloxacin degradation rate in CuMnO 2 /CeO 2 catalytic system was 3.25 times higher than that in CuMnO 2 system (0.091 min−1 vs 0.028 min−1). Moreover, the ion dissolution experiment further confirmed that the CuMnO 2 /CeO 2 catalytic system can effectively reduce the ion dissolution, which was one of the most important parameters for practical application. Thus, this work proposes a strategy for developing high activity and environmentally friendly heterogeneous Fenton catalysts based on the principles of interface enrichment and electronic regulation. [ABSTRACT FROM AUTHOR]

To combat the serious environmental menace originating from over-consumption of antibiotics in human therapy and farming industry, studies have been devoted to developing diverse technologies for antibiotics monitoring. Herein, a novel color-coded array was constructed by Ln-MOF (Ln = Eu, Tb, and Gd) fluorescent carriers for qualitative and quantitative analyses of antibiotics based on a cross-responsive mechanism. The distinct morphology identification of 10 nitro-antibiotics was obtained after processing by linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA), and concentration distributions were assessed within a range of 0–12 ppm (the detection limits all as low as ppb). Aid by the proposed array, the spiked antibiotics in lake water were successfully determined with a satisfactory recovery of 90.8%−110.8%. Notably, unknown speciation and concentration of multiple antibiotics in specific water samples can be determined, which further confirmed its admirable traceability. This research opens up a possibility to monitor environmental behavior and toxicology studies of antibiotics. [Display omitted] • A sensor array was constructed by 7 fluorescence channels of Gd/Eu/Tb-based MOF. • Array can simultaneously detect 10 antibiotics based on a cross-response mechanism. • Qualitative and quantitative analyses of 10 antibiotics were realized by the array. • The array enables rapid traceability of multiple antibiotics in real water. [ABSTRACT FROM AUTHOR]

In this work, a novel “Dumbbell-like” magnetic Fe 3 O 4 /Halloysite nanohybrid (Fe 3 O 4 /HNTs@C) with oxygen-containing organic group grafting on the surface of natural halloysite nanotubes (HNTs) and homogeneous Fe 3 O 4 nanospheres selectively aggregating at the tips of modified halloysite nanotubes was successfully synthesized. XRD, TEM, IR spectroscopy, XPS and VSM were used to characterize this newly halloysite nanohybrid and its formation mechanism was discussed. Cr(VI) ions adsorption experiments showed that the Fe 3 O 4 /halloysite nanohybrid exhibited higher adsorption ability with a maximum adsorption capacity of 132 mg/L at 303 K, which is about 100 times higher than that of unmodified halloysite nanotubes. More importantly, with the reduction of Fe 3 O 4 and electron–donor effect of oxygen-containing organic groups, Cr(VI) ions were easily reduced into low toxicity Cr(III) and then adsorbed onto the surface of halloysite nanohybrid. In addition, appreciable magnetization was observed due to the aggregation of magnetite nanoparticles, which make adsorbent facility separated from aqueous solutions after Cr pollution adsorption. [ABSTRACT FROM AUTHOR]

A typical nanoporous-geomaterial (halloysite nanotubes, HNTs) was functionalized by polyethyleneimine (PEI) grafting and the functionalized halloysite (PEI-HNTs) exhibited excellent performance for Cr (VI) removal from aqueous solution and immobilization by reduction. After PEI modification, the Cr (VI) uptake capacity of PEI-HNTs was about 64 times higher than that of the original HNTs and the maximum equilibrium removal capacity was found to be 102.5 mg g −1 at 328 K. Part of Cr (VI) was reduced to Cr (III) and then precipitated on the surface of adsorbent during the sorption process as determined by X-ray photoelectron spectroscopic analysis, suggesting that the PEI-HNTs are not only useful for Cr (VI) immobilization but also good for its reduction. The adsorption of Cr (VI) by the PEI-HNTs was fitted to Langmuir model and the kinetics of uptake could be described by a pseudo-second-order rate model very well. The results also demonstrated that PEI-HNTs could detoxify Cr (VI) at low pH value. The mechanism of uptake of Cr (VI) was postulated to be electrostatic interaction followed by its immobilization through reduction. The functionalized nano-geomaterial synthesized here could be a promising candidate of low cost for highly efficient Cr (VI) removal followed by its immobilization. [ABSTRACT FROM AUTHOR]

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. Under different excitations, the diverse UV absorption capacities of PAHs resulted in diverse spectral responses, enabling a unique chemical fingerprint for each PAH. Upon multivariate pattern recognition analysis, the array rendered high-throughput discrimination and sensitive quantification of 16 priority PAHs with 100% classification accuracy and detection limit as low as 57 nM. Moreover, the rapid and accurate screening of multiple environmental samples were also realized with the results consistent with high-performance liquid chromatography. This IFE-based reusable array is readily prepared, green and feasible, which exhibits great potential in environmental analysis and brings an advanced strategy to high-throughput sensing of more pollutants with similar structures and lack of recognition sites. [Display omitted] • Rapid, simple and cost-effective screening of 16 PAHs is realizable by sensor array. • Construction of standard database enables the screening of unknown PAHs samples. • Accurate actual sample analysis is feasible with the results matching the HPLC. • Sensor array is reusable and readily prepared. [ABSTRACT FROM AUTHOR]

Highlights: [•] The nanostructures possess excellent adsorption properties for Pb (II) ions. [•] The adsorption capacity was higher as compared to other reported absorbents. [•] It is an attractive adsorbent for removing heavy metal ions from wastewater. [•] The nanostructures also display good reusability and stability properties. [ABSTRACT FROM AUTHOR]

The increase of CO in atmosphere is a main factor leading to 'greenhouse effect', which causes more and more serious global environmental problems. The reduction of CO is a challenge for the survival of human beings, and it is also a big technical problem. CO fluid-rock interaction is a key scientific problem involved in geological storage. The CO fluid-rock interaction has a variety of multi-scale changes. Due to great differences in the quantity of surface atoms and surface energy between micron-nano-sized minerals, and ions and crystals, the speed and efficiency of CO fluid-rock interaction on a micron-nano scale are much higher than those on other scales. As is known from the natural world, the micron-nano structures of pores and the surface chemical modification of natural porous minerals (zeolite, diatomite, sepiolite, palygorskite, halloysite, etc.) should be further investigated, which can be used as the micron-nano -mineral porous materials with high capacity and high efficiency for capturing CO. Through simulating the adsorption capacity and process of CO by minerals in the natural world, the micron-nano technology is applied to calcium- and magnesium-based minerals (olivine, pyroxene, feldspar, clay, etc.) so as to improve the activity of calcium and magnesium and enlarge the reaction contact area. In this way, the efficiency of capturing and storage of CO by calcium- and magnesium-based minerals can be greatly improved. These minerals can also be used as the micron-nano-mineral materials with large capacity and high efficiency for capturing and storing CO. [ABSTRACT FROM AUTHOR]

Abstract: The influence of selenium dioxide (SeO2) on the microstructure and electrodeposition of manganese coatings obtained from a sulfate based neutral solution was investigated by material characterization methods and electrochemical techniques. The crystal structure and surface morphology of these coatings were studied by scanning electron microscopy (SEM) and powder X-ray diffraction spectroscopy (XRD), respectively. The SEM and XRD data showed that SeO2 could effectively accelerate phase transformation, and facilitate leveled and fine grain growth. The electrochemical results indicated that SeO2 could inhibit hydrogen evolution reaction and promote manganese deposition. The action of selenium dioxide in manganese deposition was found to be a reduction and adsorption mechanism. The process could be explained as following: First, Se (IV) was reduced to Se (0), and part of Se (0) future reduce to selenide, which then combined with the remainder Se (0) forming a complicate compound (multi-selenium ions). [Copyright &y& Elsevier]

Abstract: The crystalline mesoporous MgO–ZrO2 solid solutions have been fabricated by a simple evaporation induced self assembly procedure with zirconyl chloride octahydrate (ZrOCl2·8H2O) and magnesium nitrate tetrahydrate (Mg(NO3)2·4H2O) as metal precursors and triblock co-polymer of Pluronic P123 as templating agent. Small-angle X-ray diffraction (SXRD) and transmission electron microscopy (TEM) results showed that ordered mesoporous structure and worm-like mesoporous structure were obtained under different calcine temperatures. Wide angle X-ray diffraction (WXRD) indicated that the formation of homogeneous solid solutions were responsible for the stable tetragonal phase. All MgO–ZrO2 solid solutions were endowed with strong basicity (H_=9.3–12.2) and high water resistance. The Mg2+ doped into zirconia lattice could stabilize the tetragonal phase and prevent zirconia crystals from excessive growth. This kind of structure could also inhibit basic sites dissolve in water in the reaction and effectively improve the thermal stability of products. [Copyright &y& Elsevier]

Abstract: The crystalline CaO–ZrO2 mesoporous solid solution have been fabricated by a simple one-step procedure with zirconyl chloride octahydrate (ZrOCl2·8H2O) and calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) as metal precursors and triblock co-polymer of Pluronic P-123 as templating agent. Small-angle X-ray diffraction (SXRD) and transmission electron microscopy (TEM) results shows that ordered mesoporous structure and worm-like mesoporous structure were obtained when the molar ratio of Ca/Zr were 0.25 and 0.5. Wide angle X-ray diffraction (WXRD) and Raman spectra indicated that the formation of homogeneous solid solution was responsible for the stable cubic phase. All CaO–ZrO2 solid solutions were endowed with strong basicity (H− =9.3–12.2). The incorporation of Ca2+ into ZrO2 lattice led to the formation of solid solution structure and which could effectively improve the thermal stability and inhibit basic sites from leaching in the reaction. [Copyright &y& Elsevier]

Abstract: A high quality iron oxide concentrate, suitable as a feed for blast and electric reduction furnaces was recovered from high-sulfur and low-grade pyrite cinder. Pyrite cinder was treated with a hot strong alkali solution which dissolved most of the silica and alumina, leaving a solid residue and forming a precipitate which was an acid-soluble salt of aluminosilicate hydrate. The residue and precipitate were then treated with a diluted aqua regia to dissolve the precipitate and other impurities. Impurities such as the soluble silicates, aluminates and heavy metals can be extracted and produced high value-added products with several simple methods in later research. After analyzing the chemical composition and crystalline phase of raw material, the effects of different parameters on recovery efficiency of iron were carried out. The optimum reaction parameters were proposed as the following: melting at 200°C for 1.0h with 3.0M NaOH in a liquid–solid ratio of 1.0:1.2 at atmospheric pressure, followed by leaching with aqua regia solution (3.0vf.%) in a ratio of liquid-to-solid of 1.2:1.0 at room temperature for 1.5h. In optimum parameters mentioned above, the raw residue only containing 38% Fe could be purified to about 65% and the recovery yield of Fe was 86%. Furthermore, the sulfur content of product could be reduced to 0.090% from 8.0%. To reveal the mechanism of this process, the phase transformation and microstructure of the process were studied by XRD and SEM with EDS. [ABSTRACT FROM AUTHOR]

Abstract: Single-crystalline α-MnO2 nanorods have been successfully synthesized by a novel hydrothermal method based on the redox reactions between the permanganate anion MnO4 – and H2O in mixture containing KMnO4 and HNO3. The products have been characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR) and Brunauer–Emmett–Teller (BET). The results prove that the grain size of α-MnO2 nanorods with the surface area ∼95.2m2 g−1 is homogeneous with diameters ranging from 10 to 20nm. The electrochemical property of the material shows that compared with the commercial electrolytic manganese dioxide (EMD), the discharge capacity of the as-prepared α-MnO2 nanorods is increased by 70.4%, 104.1% and 135.7% at different constant currents of 50, 250 and 500mAg−1, respectively. [Copyright &y& Elsevier]

Abstract: Extraction of manganese from manganese dioxide ores was investigated using corncob as a reducing agent in dilute sulfuric acid medium. The effects of corncob amount, concentration of sulfuric acid, leaching temperature, reaction time and ore particle size were discussed. The leaching efficiency of manganese reached 92.8% while iron dissolved was 24.6% under the optimal condition which was determined for 10g of manganese dioxide ore as corncob amount of 3g, ore size of 75μm, sulfuric acid concentration of 1.9mol/L, leaching temperature of 85°C for 60min. In a word, the method provided a good leaching yield while making a productive use of corncob. [Copyright &y& Elsevier]

Abstract: Various α-MnO2 nanostructures have been successfully synthesized by a simple hydrothermal method based on the redox reactions between the MnO4 − and H2O in mixture containing KMnO4 and HNO3. The effect of varying the hydrothermal time to synthesize MnO2 nanostructures and the forming mechanism of α-MnO2 nanorods were investigated by using XRD, SEM and TEM. The results revealed an evolvement of morphologies ranging from brushy spherical morphology to nanorods depending upon the hydrothermal time. The surface area of the synthesized nanomaterials varied from 89 to 119m2/g. Electrochemical properties of the products were evaluated using cyclic voltammetry and galvanostatic charge–discharge studies, and the sample obtained by hydrothermal reaction for 6h at 120°C showed maximum capacitance with a value of 152F/g. In addition, long cycle life and excellent stability of the material were also demonstrated. [Copyright &y& Elsevier]

[Display omitted] • Exfoliated Se doped g-C 3 N 4 with 0.095 wt% Se and N vacancies was prepared. • The metal free catalyst/PMS exhibited efficient SMX degradation without extra energy. • OH and more 1O 2 enhanced SMX degradation and 1O 2 made the major contribution. • A new strategy for improving the PMS activation performance of g-C 3 N 4 was proposed. The development of low-cost and facile synthesized metal-free peroxymonosulfate (PMS) activation catalysts is paramount important for the practical remediation of organic pollution caused by antibiotics. Graphitic carbon nitride (g-C 3 N 4) as a promising alternative, to improve its PMS activation performance, we proposed an efficient method to prepare exfoliated Se doped g-C 3 N 4 (Se-g-C 3 N 4) with 0.095 wt% Se and more exposed reactive N vacancies through the thermal polycondensation of melamine and Se powder at 550 ℃. The results proved that 93.0% of sulfamethoxazole (SMX) can be degraded over Se-g-C 3 N 4 with PMS in 180 min, and the corresponding degradation rate constant of 0.0149 min−1 was even 4-fold higher than that of bulk g-C 3 N 4 (0.0039 min−1). It was found that more 1O 2 was generated and OH was further identified because of the enhanced PMS self-decomposition process, especially PMS reduction via electron transfer from Se-g-C 3 N 4. The introduction of Se atom in g-C 3 N 4 structure not only induced the formation of nitrogen vacancies to modulate the electron distribution of g-C 3 N 4 , but also favored the exfoliation of inter-facial stacking to increase the exposure of active sites due to the large atomic radius of Se. Hence, this work offered a new strategy for improving the PMS activation performance of g-C 3 N 4 by regulating its electron deficiency and exposing more reactive N vacancies simultaneously. [ABSTRACT FROM AUTHOR]

Abstract: Tri(8-hydroquinoline)aluminum (AlQ3) nanowires, nanowalls, complex nanostructure composed of microspheres and nanowires, micro-spherical chains were successfully synthesized by simple physical vapor condensation. The effect of the deposition temperature on the morphologies of AlQ3 has been investigated. Fourier transform infrared spectroscopy (FT-IR) was used to examine the chemical bonding of products as-prepared. Environmental scanning electronic microscopy (ESEM) was performed to analyze the morphologies of the samples. FT-IR results indicated that the AlQ3 molecules had a strong thermal stability. The photoluminescence (PL) spectra showed that there was no apparent blue shift because the AlQ3 molecules are bonded by relatively weak Van der Waals forces. These different structures depended on the deposition temperatures would be believed to attractive building field-emission devices and other optical devices. [Copyright &y& Elsevier]

Abstract: A novel multilayer comb-like Zinc oxide nanostructure has been successfully synthesized via pure Zn chemical vapor deposition on anodic aluminum oxide substrate at 950°C. X-ray diffraction and selected area electron diffraction indicate that the nanocombs are of wurtzite structure and single crystalline. The morphology and the microstructure of the nanocombs are investigated by the scanning electron microscopy. Transmission electron microscopy shows the growth direction, and energy-dispersive X-ray spectroscopy reveals the atomic composition ratio of Zn/O. The growth mechanism of such interesting and unique morphologies is briefly discussed. [Copyright &y& Elsevier]

Perovskites with flexible texture structures and excellent catalytic properties have attracted considerable attention in peroxymonosulfate (PMS) activation for addressing organic contaminants in water. In this study, the role of copper to promote PMS activation performance of LaMnO 3 was investigated. 100% sulfamethoxazole (SMX) degradation and 34% mineralization were achieved over copper doped LaMnO 3 while only 60% SMX was removed without TOC removal by LaMnO 3. Especially, compared with LaMnO 3 , the pseudo-first-order reaction rate constant was increased by 8.30 times when the atomic ratio of Cu/Mn was 1:3. It proved that only 1O 2 was generated in LaMnO 3 while 1O 2 , especially •OH and SO 4 •- were all detected in Cu-LaMnO 3 /PMS system. The characterization results showed that Cu induced the formation of LaMnO 3 and La 2 CuO 4 heterostructure with enhanced content of relatively low-valence Mn and Cu and abundant oxygen vacancies (OVs). Hence, the efficient PMS activation by Cu-LaMnO 3 was due to regulating the produced reactive oxygen species (ROS). A radical dominant instead of 1O 2 involved PMS activation mechanism over LaMnO 3 -La 2 CuO 4 was proposed for efficient degradation of SMX. Finally, the possible degradation pathways of SMX were discussed based on HPLC-MS analysis. This study provided a new insight of improving the catalytic activity of perovskites in PMS activation in water treatment. [Display omitted] • LaMnO 3 -La 2 CuO 4 heterostructure perovskites show excellent catalytic activity. • Complete SMX degradation and efficient mineralization are achieved over Cu-LaMnO 3. • Besides 1O 2 , especially SO 4 •- and •OH are all produced in Cu-LaMnO 3 /PMS system. • Enhanced catalytic activity can be attributed to low-valence Mn/Cu and abundant OVs. • Cu-LaMnO 3 provides a promising catalyst alternative for PMS activation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Charge density is improved through In doped Cu 2 Se. • CuInSe 2 led to a superior TOC removal rate of 71.5% for OFX. • Electronic utilization efficiency is altered by different In doping ratios. • CuInSe 2 showed the highest electron utilization efficiency. • CuInSe 2 exhibited the highest radical conversion rate with the value of 9.83 × 10-4. Local electron density at the reaction center atoms is closely related to the H 2 O 2 activation performance of a heterogeneous Fenton-like catalyst. However, the random electron transfer often restricts the oriented electron delivery to the active center. In this study, we proposed that only efficient electrons and their ordered transfer were desirable to boost Cu(II)/Cu(I) cycle for H 2 O 2 activation based on regulation of local electron density and electron transfer efficiency of Cu atoms in Cu 2 Se. Experimental results and density function theory (DFT) calculation proved that Indium atom can drive electrons to accumulate on Cu active center and provide an efficient electron transfer pathway in CuInSe 2 (from Se → Cu to In → Se → Cu). Hence, compared with Cu 2 Se, more reductive electrons can participate in the H 2 O 2 activation process for CuInSe 2 , which resulted in much more efficient ofloxacin (OFX) degradation with a TOC removal rate up to 71.5 %. The electron exchange capacity of CuInSe 2 was further regulated by changing the atomic ratios of Cu and In elements including CuInSe 2 , Cu 1.5 In 0.5 Se 2 and Cu 1.75 In 0.25 Se 2. CuInSe 2 had the lowest electron exchange capacity and exhibited the highest reaction activity with a radical transformation efficiency from H 2 O 2 of 9.83 × 10-4, in contrast, the value for Cu 1.75 In 0.25 Se 2 was 2.78 × 10-4. We provided a new insight for improving the heterogeneous Fenton catalytic performance. [ABSTRACT FROM AUTHOR]

• Dozens of pesticides are rapidly and accurately screened from complex real samples. • Diverse response of pesticides to cholinesterase ensures high-throughput output of array. • Simple database was established through analysis of multiple standard pesticides. • Accurate actual sample analysis is feasible, and the results match the HPLC. • The detection limit of the array is as low as 16 ppb. Accurate screening of organophosphorus and carbamates pesticides from the complex real sample is crucial for water quality analysis and food safety control. Herein, a simple, low-cost and accurate pesticides screening method based on a high-throughput optical array system assembled by multiple cholinesterases (ChE) and thiocholine (TCh) sensors is described. The detection mechanism is that the inhibition of ChE activity by pesticides reduces the TCh produced by the hydrolysis of butyryl/acetylthiocholine iodide, thus changing the fluorescence intensity of TCh sensor. The diverse response of ChEs to pesticides and different affinity of sensors to TCh ensure the high-throughput and distinguishable signal output, which allow the establishment of high discrete pesticide database with intra-cluster agglomeration and inter-cluster dispersion. By using the database, the screening of unknown real contaminated samples were successfully operated, and the screened pesticide species and concentrations were consistent with high-performance liquid chromatography. This screening strategy demonstrates the feasibility of replacing existing complex mass spectrometry-based screening strategy with simple optical analysis, providing a new idea for the development of simple accurate screening technologies for widespread organic pollutants including pesticides. [ABSTRACT FROM AUTHOR]

• Mg/Al HT was firstly used as ozonation catalyst and has satisfied catalytic activity. • COD removal efficiency of Mg 3 /Al HT was even higher than α-FeOOH (68 % vs. 50 %). • Not only OH but also O 2 − and 1O 2 were the reactive species for 2,4-D degradation. • Surface acid and base site are the active centers of Mg/Al HT in catalytic ozonation. • Mg/Al HT provides a promising catalyst alternative for catalytic ozonation. The Mg/Al hydrotalcite (Mg/Al HT) was firstly used as a heterogeneous ozonation catalyst and 2,4-dichlorophenoxyacetic acid (2,4-D) was efficiently degraded by Mg 3 /Al HT with a COD removal of 68 %. It was higher than that of α-FeOOH with a COD removal of 50 %. The effects of Mg/Al atomic ratio, phosphate and pyrrole on the ozonation performance of Mg/Al HTs were also investigated. The X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption experiment and temperature programmed desorption of adsorbed CO 2 or NH 3 were used to characterize the surface properties of Mg/Al HT. The surface acidity and basity was proven to be responsible to the excellent ozonation activity of Mg/Al HT. The results of electron spin resonance (ESR) analysis and probe experiments confirmed that OH, O 2 − and 1O 2 were involved in the 2,4-D degradation process and their contributions are as followed: OH > O 2 - >1O 2. The synergistic effect of surface acid (ozone adsorption center) and base sites (catalytic center) determines Mg/Al HT in the enhanced catalytic ozone decomposition into reactive species. More important, the transition metal free based Mg/Al HTs is steady, non-toxic, naturally abundant and environment friendly, which provided a promising alternative in practical water treatment by catalytic ozonation. [ABSTRACT FROM AUTHOR]

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 1O 2 during the sulfamethoxazole (SMX) degradation process under oxic conditions. Two reaction stages of SMX degradation by pyrite were observed. The SMX concentration decreased by 70% rapidly in the first 12 h after the reaction was initiated, then, the removal rate began to decrease as the SMX concentration decreased. Importantly, •OH and O 2 •− were the dominant oxidizing species in stage one, while 1O 2 was responsible for the further degradation of SMX in stage two. The self-acclimated mechanism of pyrite was proven to be caused by the conversion of oxidative species at the surface of pyrite. This process can overcome the shortages of •OH such as ultrashort lifetime and limited effective diffusion in the decontamination of micropollutant. Moreover, different reactive oxygen species will lead to different degradation pathways and environmental toxicity while degrading pollutants. This finding of oxidizing species' self-acclimation mechanism should be of concern when using pyrite for water treatment. [Display omitted] • A self-acclimation mechanism of pyrite in decontamination was explored and proposed. • Two reaction stages of the SMX degradation by pyrite were observed. • Short-lived •OH was converted to long-lived 1O 2 with pollutant's amount decrease. • The changes of ROS for pyrite result in a different SMX degradation behavior. [ABSTRACT FROM AUTHOR]

Metallic phase molybdenum sulfide (1T‐MoS2) is considered as an attractive electrode material for sodium‐ion batteries (SIBs) owing to its abundant active sites, metallic conductivity and high theoretical capacity. Unfortunately, the thermodynamic unstable characteristic under natural conditions makes 1T‐MoS2 difficult to synthesize directly, which greatly hinders its further applications. Herein, an electron modulated and phosphate radical stabilized strategy is employed to construct stable 1T‐rich MoS2 (1T‐P‐MoS2). The PO43− groups are intercalated into MoS2 via a simple one‐step synthesis process, which enlarges the interlayer spacings and improves the insertion/extraction kinetics of Na+. Density functional theory (DFT) calculations and experiments demonstrate that the PO43− can give partial electrons to Mo upon PO43− intercalation, which triggers the reorganization of Mo 4d orbitals, resulting in a spontaneous phase transition of MoS2 from 2H to 1T phase, thereby enhancing the electrical conductivity of MoS2. The obtained 1T‐P‐MoS2 exhibits ultra‐fast charged properties (up to 277.1 mAh g−1 at 40 A g−1, discharged/charged within 25 s) and excellent cycling performance (up to 498.9 mAh g−1 after 300 cycles at 1 A g−1). This work provides a feasible technical solution and analyses the deep mechanisms on tuning of metal sulfide electrodes for advanced SIBs. [ABSTRACT FROM AUTHOR]

To develop a convenient method for simultaneous detection of As(III/V), Cr(III/VI), and Fe(II/III), three morphologies of CeO2 oxidase have been prepared. Based on the difference in oxidase activity and binding ability with substrate TMB of CeO2 of 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 1.68 µg/L. The analysis of environmental samples with multiple metal ions (binary and ternary mixtures) co-existing has confirmed that the sensor array can achieve simultaneous qualitative and quantitative results for composite samples. This study not only revealed the influencing factors of crystal morphology regulation on oxidase activity, but also provided a scheme for the morphology detection of easily convertible metal ions in the field through the construction of the sensor array. [ABSTRACT FROM AUTHOR]

Graphical abstract A new hydrophilic ratiometric hybrid sensor has been developed for the visual detection of Fe3+ with the fluorescence color changing from red to yellow and a lower detection limit of 26.5 nM. Highlights • A novel hydrophilic ratiometric sensor for instant visual detection of Fe3+. • The fluorescence response occurs instantaneously and reaches stability less than one second. • The detection limit of Fe3+ is as low as 26.5 nM. • The paper sensor has been prepared for the visual and on-site detection of Fe3+. Abstract A novel hydrophilic ratiometric fluorescence sensor for instant visual detection of Fe3+ was successfully prepared by integrating silica-embedded CdTe quantum dots (QDs) with rhodamine derivative. The rich hydrophilic group and large specific surface area of CdTe@SiO 2 QDs favored the adsorption of rhodamine derivative on silica and improvement of its water solubility. The results proved that the ratiometric fluorescence sensor shows a much higher selectivity towards Fe3+ with the detection limit as low as 26.5 nM than other typical cations and anions in aqueous solution. Moreover, the fluorescence response occurs instantaneously and reaches stability less than one second. Additionally, a simple and rapid paper-based analytical device was designed for on-site and visual detection of Fe3+ in actual water samples. Hence, this study provided a good candidate for the on-site and visual sensing of Fe3+ in the environmental analysis. [ABSTRACT FROM AUTHOR]

Graphical abstract A ratiometric fluorescence assay for detection of mercuric ions (Hg2+) has been developed using sole intrinsic dual-emitting gold nanoclusters (DE-AuNCs). The addition of Hg2+ quenched the 610 nm emission, and the 810 nm emission remained unchanged. Highlights • Intrinsic dual-emitting AuNCs were prepared by glutathione reduced chloroauric acid. • A ratiometric fluorescence sensor without auxiliary fluorophore for Hg2+ was provided. • The proposed ratiometric method exhibited high sensitivity and selectivity. • 0.19 ppb Hg2+ LOD of AuNCs was much lower than the WHO drinking-water guideline. Abstract Ratiometric fluorescence sensing based on intrinsic dual-emitting nanomaterials is very intriguing for their simplicity and efficacy. However, intrinsic dual-emitting gold nanocluster-based fluorescence ratiometry remains unexplored. In this work, a ratiometric fluorescence assay for detection of mercuric ions (Hg2+) has been developed using sole intrinsic dual-emitting gold nanoclusters (DE-AuNCs). The DE-AuNCs, simply synthesized by reducing chloroauric acid with an appropriate amount of glutathione, had two distinct intrinsic emission bands peaked at 610 nm and 810 nm respectively. When exposed to Hg2+, the 610 nm emission of the DE-AuNCs was remarkably quenched serving as a reporter signal, while the 810 nm emission almost kept unchanged serving as a reference signal, and thus giving a ratiometric signal. This ratiometric method showed high sensitivity and selectivity for sensing Hg2+ with low LOD down to 0.19 ppb which is quite lower than the WHO drinking-water guideline for inorganic mercury, and was successfully applied to the detection of Hg2+ in environmental water samples. [ABSTRACT FROM AUTHOR]

The increasing demand for new materials with narrow bandgap energy, capable of harvesting the photons in the visible range, is central in the remediation of environmental pollutants by photocatalytic reactions. For the first time, we report a novel visible light driven photocatalyst of Bi 2 Se 3 /Bi 1.007 Se 0.993 by the formation of solid solution composite. Both the individual Bi 2 Se 3 and Bi 1.007 Se 0.993 have very low photocatalytic efficiency under visible light irradiation; however, Bi 2 Se 3 /Bi 1.007 Se 0.993 provides much higher efficiency in decomposing methylene blue (MB). Especially in the presence of H 2 O 2 , the reaction rate was enhanced by 15 times and 100% of MB degradation was obtained in 90 min. Characterization results confirmed that the bandgap of Bi 2 Se 3 /Bi 1.007 Se 0.993 was greatly broadened to 1.38 eV compared with Bi 2 Se 3 of 0.3 eV, which matched well with visible range. Moreover, the relative conduction band position vs. NHE of Bi 2 Se 3 /Bi 1.007 Se 0.993 was −0.3 V, which was more negative than that of Bi 1.007 Se 0.993 of +0.2 V. It was responsible to the excellent photocatalytic activity due to harvesting the photons in the visible range. Finally, N-type semiconductor based reduction O 2 to O 2 •- and photoreduction of H 2 O 2 into • OH involved reaction mechanism under the visible light irradiation was proposed based on all the experimental results. [ABSTRACT FROM AUTHOR]

Effect of wastewater characteristics on bioenergy recovery in sewage treatment by anaerobic membrane bioreactor (AnMBR) was investigated. Based on COD removal, sludge concentration change and COD mass balance, nonionic surfactant or operation at 20–25 °C had no effect on the energy recovery with COD conversion of 72–79%. The anaerobic microbes can cope with the characteristic by releasing more SMP/EPS or changing its community structure. Compared with Control (6.99 × 10 7 kJ/d, HRT 12 h), with suspended solid or operation at 15 °C and 10 °C, the captured energy was only 5.90 × 10 7 kJ/d, 6.0 × 10 7 kJ/d and 3.10 × 10 7 kJ/d, respectively while the energy in dissolved methane was 1.08 × 10 7 kJ/d, 0.98 × 10 7 kJ/d and 1.26 × 10 7 kJ/d. Hence, the recovery efficiency was decreased by 15.6%, 14.2% and 55.7%. The recovery also decreased by 26% (5.17 × 10 7 kJ/d) in the presence of anionic surfactant. The toxicity of anionic surfactant to the anaerobic microbes and lower growth rate of microorganism at psychrophilic temperatures were responsible to the decrease of bioenergy recovery efficiency. SS accumulation will finally increase the loading rate of sludge and decrease the bioenergy recovery from the long-term view. [ABSTRACT FROM AUTHOR]

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. For the actual water samples with coexistence of the above 4 tetracyclines, their simultaneous morphology identification and accurate quantitative detection can also be realized through simple spectrometric measurement. In addition, the selective and competitive experiments have been carried out on the pollutants widely present in water, and the results have also confirmed that other pollutants could not interfere with the detection of the above 4 tetracyclines. It is undeniable that this work will conveniently and visually reveal the existence information and geographical distribution characteristics of different tetracycline antibiotics in the environment and their action mechanism on organisms. [Display omitted] • The white fluorescent Eu/Tb@CDs has been synthesized by one-pot method. • The LOD of Eu/Tb@CDs towards TC, OC, CC and DC were all lower than 1 nM. • Arrays were constructed to identify and detect coexisting multiple tetracyclines. • A single probe can recognize and detect multiple tetracyclines simultaneously. [ABSTRACT FROM AUTHOR]

In this study, MgAl 2 O 4 (cLDHs) with a typical spinel structure was synthesized by calcination of Mg/Al layered double hydroxides (LDHs) and was used as adsorbent for selenite (IV) removal from contaminated groundwater. Based on XRD, SEM/TEM and XPS analysis, the layered structure of LDHs was completely destroyed after calcination and pure bimetal oxides with flakiness structure was obtained. Compared with Mg/Al LDHs (66.89 mg/g), MgAl 2 O 4 (cLDHs) exhibited an excellent selenite removal performance and the maximum adsorption capacity of selenite was 179.59 mg/g. The results indicated that Freundlich isotherm model is suitable to describe the adsorption equilibrium of selenite by cLDHs and the selenite adsorption also followed pseudo-second-order kinetics. Moreover, the influence solution pH and co-existed anion on the selenite by cLDHs was also investigated in detail. According all the experimental results, the removal mechanism of selenite was further discussed. Besides the surface adsorption and ion exchange by LDHs, most of selenite were removed by the intercalation into the interlayer region during the reconstruction process. [ABSTRACT FROM AUTHOR]