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There is an increasing scientific interest in the detection of genotoxic impurities (GTIs), with nitrobenzene compounds being considered potential genotoxic impurities due to their structural alerts, which demonstrates a threat to drug safety for patient. While current reports on the detection of nifedipine impurity primarily focus on general impurities in nifedipine. In this study, an effective and simple gas chromatography-mass spectrometry (GC-MS) method was established and verified for the separation and quantification of 2-nitrotoluene, 2-nitrobenzyl alcohol, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde, and 2-nitrobenzyl bromide in nifedipine, which have not been previously reported. The validation of this GC-MS method was conducted following the International Conference of Harmonization (ICH) guidelines, exhibiting good linearity within the range of 2-40 μg/g and accuracy between 84.6 % and 107.8 %, the RSD% of intra-day and inter-day precision was in the range of 1.77-4.55 %, stability and robustness also met acceptance criteria. This method filled the gap in detection method for nitrobenzene compounds in nifedipine, offering a novel method and technical support for nifedipine quality control., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Central composite design based RP-HPLC method optimization for the synchronized analysis of Efonidipine Hydrochloride Ethanolate (EFE) and Chlorthalidone (CHL) in tablet. The effective separation was performed using Inertsil ODS C18 column (250 × 4.6 mm, 5 μm), PDA detector with 0.05 M KH2PO4 Buffer (pH 4.5): Acetonitrile (40:60%v/v) mobile phase. Independent variables were investigated include the concentration of KH2PO4 (X1) and flow rate of mobile phase (X2). Based on responses obtained (retention time, resolution and tailing factor), the optimum condition selected was X1 = 40% and X2 = 1 ml/min. Optimized HPLC condition was validated by assessing validation parameters and it meets the acceptance criteria set by ICH. The linear calibration curve was found to be in the quantity range 6.25-18.75 and 20-60 μg/ml Assay of drugs was 100.94 and 100.06% for CHL and EFE. The validated RP-HPLC-PDA method can be used for routine analysis of EFE and CHL in tablet., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The wide use and high polarity of nitrobenzene compounds (NBCs) have caused a concern for their residues in daily beverages. Herein, the covalent organic frameworks (COFs) with abundant carboxyl were ingeniously designed by introducing a novel modulator, and further developed as solid phase microextraction (SPME) coatings. Due to the enhanced polar interaction, the extraction efficiencies of modified COF for NBCs were sharply increased. After coupling the high-performance SPME fiber with gas chromatograph-mass spectrometry (GC-MS), an ultrasensitive analytical method was developed, with a wide linear range (0.50-5000 ng/L), and low limits of detection (0.15-3.0 ng/L). More importantly, the method was highly feasible and practical, leading to the precise determinations of trace NBCs from variously matrix-complicated samples. This work provides a viable and efficacious approach for the extraction and analysis of polar pollutants form complicated matrices, and is of great significance for mild COF modification and its extended applications in analytical chemistry., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Five random copolymers comprising styrene and styrene with pendant fluorophore moieties, namely pyrene, naphthalene, phenanthrene, and triphenylamine, in molar ratios of 10:1, were synthesized and employed as fluorescent sensors. Their photophysical properties were investigated using absorption and emission spectral analyses in dichloromethane solution and in solid state. All copolymers possessed relative quantum yields up to 0.3 in solution and absolute quantum yields up to 0.93 in solid state, depending on their fluorophore components. Fluorescence studies showed that the emission of these copolymers is highly sensitive towards various nitroaromatic compounds, both in solution and in the vapor phase. The detection limits of these fluorophores for nitroaromatic compounds in dichloromethane solution proved to be in the range of 10 -6 to 10 -7 mol/L. The sensor materials for new hand-made sniffers based on these fluorophores were prepared by electrospinning and applied for the reliable detection of nitrobenzene vapors at 1 ppm in less than 5 min.

Zero valent iron (ZVI) applications to remediation of shallow groundwaters can be affected by dissolved oxygen (DO) and organic ligands. To explore the intersection between these complicating factors, this study thoroughly characterized the reactions of nitrobenzene (NB) with ZVI in the presence DO and the model ligand ethylene diamine tetraacetic acid (EDTA). The results showed that NB is degraded by both ZVI reduction and ZVI-induced advanced oxidation under oxygen-limited conditions. The contribution of ·OH to the degradation of NB increased with time so that nearly 39% of NB was oxidized by ·OH at 15 min (pH = 3), but reduction was still the main pathway of NB transformation throughout. NB reduction products, such as aniline (AN), were also oxidized by ·OH. The lower the pH, the greater the contribution of advanced oxidation, but DO was the limiting factor for ·OH generation. Only 4.7% NB was fully degraded by ring opening and/or mineralization because the production of •OH was limited by low DO. After the transformation of NB and AN, other benzene ring and nitrogen-containing intermediates were identified (e.g., p-nitrophenol, p-aminophenol, hydroquinone, and p-benzoquinone). The removal of total organic carbon and total organic nitrogen was minimal. The results suggested that the relative doses of ZVI, DO, and iron-complexing ligands can be balanced for the optimal (rapid and deep) removal of organic contaminants.

Nitrobenzene compounds are highly toxic pollutants with good stability, and they have a major negative impact on both human health and the ecological environment. Herein, it was found for the first time that fluorescent DNA-silver nanoclusters (DNA-AgNCs) can catalyze the reduction of toxic and harmful nitro compounds into less toxic amino compounds with excellent tolerance to high temperature and organic solvents. In this study, the reduction of p-nitrophenol (4-NP) as a model was systematically investigated, followed by expending the substrate to disclose the versatility of this reaction. This report not only expanded the conditions for utilizing catalytic reduction conditions of DNA-AgNCs as an efficient catalyst in the control of hazardous chemicals but also widened the substrate range of DNA-AgNCs reduction, providing a new angle for the application of noble metal nanoclusters.

Oxidations of aniline (AN) initiated by OH-radicals are simulated in the temperature range 200-400 K using DFT/M06-2X/6-311++G(2df,2p) and ab initio ROCBS-QB3 levels. Chemical kinetics of such reactions were investigated based on several approaches including classical transition state theory (TST), conical variational transition state theory (CVT), and Rice-Ramsperger-Kassel-Marcus master equation (RRKM-ME) theories. Under atmospheric conditions, the reaction of OH radical with AN and the subsequent reactions with O 2 molecules are investigated. The results indicate that the majority of O 2 addition goes to the anti-directions with a branching ratio of 97.7% and produces the bicyclic peroxy radicals (BPRs) that can react with NO radical to form bicyclic alkoxy radicals (BARs). The latter compounds can be stabilized either by cyclization or via ring cleavage., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The searching for efficient and economical redox mediators to promote the treatment of wastewater containing recalcitrant organic compounds is greatly needed. In this study, the redox mediator activities of four different lignite samples to facilitate the bioreduction of nitrobenzene by Shewanella oneidensis MR-1 were tested for the first time. The initial nitrobenzene reduction rate was increased by 40.4%-90.3% in the presence of 50 mg/L of different lignite samples. Lignite collected from Xinjiang (XJL) having more oxygenated groups performed better in enhancing nitrobenzene bioreduction. The stimulating effects increased with the increase of lignite dosage (0-200 mg/L) and the decrease of lignite particle size (150-0.1 μm). However, the pristine XJL samples with assorted sizes of particles exhibited better stimulating effects than size-fractionated ones, implying that different-sized XJL particles might have synergetic effects on the bioreduction process. When humic acid or iron was removed from XJL, its promoting effects were decreased, demonstrating the crucial roles of both components in lignite-enhanced nitrobenzene bioreduction. Nitric acid treatment could form more oxygenated moieties on lignite surface, which played vital roles in promoting nitrobenzene bioreduction. The initial nitrobenzene bioreduction rate in the presence of HNO 3 -treated XJL was 80.8% higher than that obtained with pristine XJL. This study proposed an effective and readily available redox mediator that could be applied to promote the bioreduction of recalcitrant electrophilic pollutants., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The present study aimed to explore the eco-friendly synthesis of prism-like silver oxide nanoparticles (Ag 2 ONPs) from nappa cabbage extract and its p -nitrophenol sensing activity. The prepared Ag 2 ONPs were characterized by X-ray diffraction (XRD), field-emission scanning spectroscopy (FESEM), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and ultraviolet (UV)-visible light spectral analysis (UV-Vis). p -Nitrophenol sensing properties of the prepared nanoparticles were also determined using a simple I-V method. The results showed that the as-prepared Ag 2 ONPs have a face-centered cubic (fcc) crystalline nature and a prism-like morphology with particle size in the range 21.61-92.26 nm. The result also showed a high intensity of the (111) facet, making the Ag 2 ONP-carbon black/nickel foam electrode (Ag 2 ONP-C/NFE) exhibit a high-performance response to p -nitrophenol spanning a wide range of concentrations from 1.0 mM to 0.1 pM and a response time of around 5 s, indicating a high potential for water treatment applications., Competing Interests: The authors declare no conflicts of interest.

Copper modified carbon nitride (CuCN) was prepared by a hydrothermal self-assembly reaction and following high temperature thermal polymerization process. Finally, the sample exhibits uniform one-dimensional tubular structure. Interestingly, the separation efficiency of electron-hole pair is improved, and more catalytic active sites are exposed due to the special hollow structure. Meanwhile, the presence of copper element narrows its band gap, leading to the enhancement of photocatalytic degradation performance under simulated sunlight. In addition, the effect of CuCN on dehydrogenase activity of activated sludge was determined by TTC reduction method. After adding CuCN-2, the activity of activated sludge reached 0.134 μmol g -1  min -1 , which indicated that the prepared CuCN-2 had good biocompatibility. It is suitable for both photocatalytic process and activated sludge treatment process. Therefore, the combination of photocatalytic technology and activated sludge process can further completely degrade organic pollutants. We found that CuCN could protect the survival and growth of microorganisms in activated sludge, so that the degradation efficiency of CuCN to nitrobenzene could reach 94.4 %. Therefore, CuCN has broad application prospects in photocatalytic-activated sludge combined treatment., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interests., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this work, 3D hierarchical Cu 2 SnS 3 @SnS 2 flower assembled from nanopetals with sandwich-like Cu 2 SnS 3 -SnS 2 -Cu 2 SnS 3 double interfacial heterojunction was successfully designed and synthesized on fluoride doped tin oxide (FTO) for photoelectrochemical (PEC) sensor by in situ electrodeposition p-type Cu 2 SnS 3 nanoparticles on both inner and outer surfaces of n-type SnS 2 nanopetals. The unique double interfacial heterojunction simultaneously combines 3D flower-like architectures to drastically increase the light trapping and absorption in visible-near infrared range (Vis-NIR), and dramatically inhibites the charge carrier recombination, which is crucial for boosting the PEC activity. Benefitting from the shape and compositional merits, the Cu 2 SnS 3 @SnS 2 heterojunction possess dual-mode signal by controlling the electrodeposition time to manipulate the composition ratio of Cu 2 SnS 3 and SnS 2 . The Cu 2 SnS 3 @SnS 2 /FTO electrode not only exhibits excellent photoeletro-reduction capacity for ultra-sensitive sensing trace persistent organic pollutant (nitrobenzene, NB), but also presents photoeletro-oxidization activity for high selective detection of L-cysteine (L-Cys) without any auxiliary enzyme under the light illumination. Dual mode sensor displayed superb performance for the detection of NB/L-Cys, showing a wide linear range from 100 pM to 300 μM/10 nM to 100 μM and a low detection limit (3S/N) of 68 pM/8.5 nM, respectively. Such a tunable double interfacial heterojunction design opened up new avenue for constructing multifunction PEC sensing platform., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In our previous study, biochar (BC) supported sulfidated nano zerovalent iron (S-nZVI@BC) was prepared for nitrobenzene (NB) reduction. In this study, in order to further improve the reduction performance of S-nZVI@BC, BC was modified before the loading of S-nZVI through three methods: oxidant (H 2 O 2 ) pretreatment, alkali (NaOH) pretreatment and acid (HCl) pretreatment. The results indicated that S-nZVI could be evenly distributed onto HCl-BC due to increased surface area, negative surface charge and increased acidic functional groups on HCl-BC. At an initial concentration of 200 mg L -1 , NB could be completely removed by S-nZVI@HCl-BC within a reaction time as short as 60 min, indicating rather excellent performance of S-nZVI@HCl-BC. NB reduction performance followed the order: S-nZVI@HCl-BC > S-nZVI@NaOH-BC > S-nZVI@BC > S-nZVI@H 2 O 2 -BC. The mass ratio of S-nZVI and HCl-BC was optimized in terms of NB removal efficiency, with 3:1 being identified as the best mass ratio. Furthermore, the mechanism involved in the enhanced NB reduction by S-nZVI@HCl-BC was proposed. This study demonstrated that S-nZVI@HCl-BC is a promising alternative for efficient NB removal from wastewater., (Copyright © 2019 Elsevier B.V. All rights reserved.)

N-doped graphene (NG), S-doped graphene (SG), and N and S co-doped graphene nanocatalysts with different doping sequences (N-SG and S-NG) are successfully synthesized by a facile low-temperature hydrothermal method. By changing the synthetic sequence, S-NG significantly increases the electron transport rate of the sensor and the electrocatalytic ability compared to NG, SG, and N-SG due to the optimal proportion of doping element content and suitable N- and S-bonding configurations. The origin of the synergistic effect of N and S co-doped graphene is confirmed. Traces of S doping greatly enhance the electrochemical performance. The large volume of S-O x groups may prevent the analytes from approaching the catalytic sites of the sensing materials due to a steric hindrance effect. S-NG, which possesses less S-O x groups, exhibits better performance than N-SG. Pyridinic N plays an important role in enhancing the electrochemical activity and conductivity. The simultaneous determination of aniline (AN), p -phenylenediamine (PPD), and nitrobenzene (NB) as typical toxic pollutants is performed by employing the S-NG nanoarchitecture. The detection limits (S/N = 3) for AN, PPD, and NB are 0.023, 0.051, and 0.216 μM, respectively. In addition, the S-NG sensors also have excellent anti-interference, stability, and reproducibility. The precise control and synthesis of multiheteroatoms into graphene represent a promising strategy to enhance the electrocatalytic performance in energy and environmental fields.

Detection of nitroaromatic compounds (NACs) is an important applied task for environmental monitoring, medical diagnostics, and forensic analysis. However, detection of NAC vapors is challenging owing to their low vapor pressure and relatively weak sensitivity of the existing detection techniques. Here, we propose a novel concept to design fluorescence (FL) detection platforms based on chemical functionalization of nanotextured dielectric surfaces exhibiting resonant light absorption, trapping, and localization effects. We demonstrate highly-efficient NAC vapor sensor with selective FL-quenching response from monolayers of carbazole moieties covalently bonded to a spiky silicon surface, "black" silicon, produced over the centimeter-scale area using simple reactive ion etching. The sensor is shown to provide unprecedented ppt (10 -12 ) range limits of detection for several NAC vapors. Easy-to-implement scalable fabrication procedure combined with simple and versatile functionalization techniques applicable to all-dielectric surfaces make the suggested concept promising for realization of various gas sensing systems for social and environmental safety applications.

To eliminate pentachloronitrobenzene (PCNB) residue in PCNB-contaminated environment, the degradation potential of Pseudomonas putida QTH3 to PCNB was evaluated in this study. Peudomonas putida QTH3 could grow well in mineral salt medium (MSM) containing PCNB as sole carbon and was able to degrade PCNB efficiently, whereas the degradation rate of P. putida QTH3 to PCNB increased gradually, and reached 49.84% in 35 days. The degradation rates of P. putida QTH3 to 13 tested organochlorine compounds found to be 10.85%-42.51% after 14 days. The metabolites during PCNB biodegradation by P. putida QTH3 were identified as catechol, 2, 3, 5, 6-tetrachloroaniline (TCA), 2, 3, 4, 5- TCA, 2, 3, 4, 5, 6-pentachloroaniline (PCA) and pentachlorothioanisole (PCTAs). Furthermore, possible degradation pathway of PCNB by P. putida QTH3 was proposed. The degradation rates of intracellular enzyme and extracellular enzyme were 44.73% and 8.93% after incubation with 100 mg L -1 PCNB for 30 min, respectively. Thus, intracellular enzyme is a major enzyme responsible for PCNB degradation. The results indicate that P. putida QTH3 can be a suitable organism for the degradation of PCNB, and facilitate its potential for the bioremediation of the environments contaminated with major organochlorine compounds used during this study., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Solid phase extraction has been increasingly applied for the detection of organic micropollutants (OMPs). However, time-consuming and high-cost disadvantages also limit the widespread use of this method, especially for the extraction of large-volume field water samples. In this study, a gas chromatography-mass spectrometry (GC-MS) method based on the magnetic microsphere (M150) solid-phase-extraction (MSPE) was established to investigate the OMPs in source water throughout the whole Huai River. In brief, the results demonstrated that the extraction efficiency of the M150 was superior to that of C 18 and HLB for the selected OMPs, including species of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), phthalate esters (PAEs) and nitrobenzenes (NBs), and the method detection limits of M150 for these OMPs were comparable to those of C 18 and HLB. The optimized conditions of extraction and elution were the 100 mg/L dosages of microspheres, extraction time of 60 min and pH of 2, and the eluent with a similar polarity, hydrophobicity and molecular structure to the OMPs rendered higher elution efficiencies. A total of 21 types of OMPs affiliating to PAHs, OCPs, PAEs and NBs were detected by the established method, with the total concentrations of 505-2310 ng/L in source water of the Huai River. Spatial differences of the OMPs were also observed, demonstrating the link between pollutant profiles and geographical locations. This study provides an alternative to enrich OMPs in filed water samples, and it reveals pollutant profiles of source water throughout the whole Huai River., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This study aimed to enhance treatment of wastewater containing nitrobenzene (NB) and sulfate using biocathode enriched with sulfate-reducing bacteria in microbial electrolysis cell (MEC). Artificial wastewater with 50 mg L -1 NB and 200 mg L -1 sulfate was used as the catholyte. With 0.8 V applied voltage, removal efficiencies of NB and sulfate reached 98% and 34%, respectively, within 36 h. Aniline and sulfide were the main reductive products in the catholyte with concentrations increased to 0.32 and 0.51 mM, which accounted for 97% and 78% of the removed NB and sulfate, respectively. Sulfate-reducer Desulfovibrio sp. and Wolinella sp. played the dominant role in the biocathode for the reductions of sulfate and NB. Analyses of scanning electron microscope and X-ray photoelectron spectroscopy showed the formation of elemental S on the biocathode surface. The relative abundance of sulfur-oxidizing bacterium Thioclava sp. reached 24% on the biocathode. The results indicated that the oxidation process from S 2- to S 0 occurred on the biocathode, which provided electrons to biofilm for NB reduction. The MEC with sulfate-reducer enriched biocathode can be used as an alternative to treat complex wastewater containing NB and sulfate., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Experiments were conducted to develop a method for the determination of a set of 17 military-relevant energetic compounds (including nitroaromatics, nitramines, and nitrate esters) in 5 types of marine tissues (Dungeness crab, Manila clam, starry flounder, sea cucumber, and geoduck) using reversed-phase high performance liquid chromatography with a UV detector (RP-HPLC-UV). Dry-ice grinding was evaluated and found to be an excellent method of sample homogenization prior to sample extraction and determination. An extract cleanup procedure based on solid-phase extraction was assessed. A cleanup procedure using solid phase extraction was adequate for the removal of interferences prior to HPLC analysis for the five marine tissue matrices tested. Mean method detection limits (MDLs) were estimated using two columns at two wavelengths (254 and 210 nm) and ranged from 17 to 293 µg/kg for the five tissue matrices tested. A six-laboratory intercomparison test was conducted to evaluate the performance of the method, each analyzing five marine tissue matrices fortified at three levels. The same marine tissues were used in the laboratory intercomparison study except Pacific halibut was substituted for starry flounder. Overall, USEPA Method 8330B modified for tissue analysis showed suitable detection capability, analytical accuracy, precision, sensitivity, linear range, and robustness for sixteen (16) of the seventeen (17) analytes, for all five (5) of the marine tissue matrices studied. The exception was tetryl that proved to be unstable for all matrices as has been found for soils and sediments., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

The authors report on an energy transfer based fluorometric approach for the detection of nitroaromatic pollutants. This is achieved using 4-mercaptobenzoic acid (4-MBA)-capped CaF 2 :Tb 3+ nanocrystals that were synthesized by a microwave procedure. 4-MBA acts as both a capping agent and a sensitizer for the Tb 3+ ions in CaF 2 host matrix. This approach is different from the earlier studies where Ce 3+ is generally used as the sensitizer for the Ln 3+ ions. The use of capping ligand as sensitizer has the feature that binding of nitroaromatics directly to the sensitizer can alter the energy transfer efficiency between the sensitizer and the Tb 3+ ions. The fluorescent nanocrystal probe doped with 2% of Tb 3+ displays green emission with a peak at 542 nm if photoexcited at 311 nm. The emission is quenched if the nanocrystals are exposed to nitroaromatic compounds such as 4-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol (picric acid), 4-nitrotoluene, 2,4-dinitrotoluene and 2,4,6-trinitrotoluene. These analytes also cause a (longwave/shortwave) shift in the excitation maxima which helps in identifying the individual nitroaromatic compound using single nanoprobe. The respective detection limits (by applying the 3σ/K criterion) are 0.86 μM, 0.83 μM, 0.78 μM, 0.36 μM, 1.5 μM, and 1.96 μM. Graphical abstract Schematic illustration of the use of 4-mercaptobenzoic acid (MBA)-capped CaF 2 :Tb 3+ nanocrystals as a fluorescent nanoprobe for the detection of nitroaromatic analytes. The Tb 3+ ions show strong green fluorescence via 4-MBA-induced ligand sensitization. The specific π interaction between 4-MBA capped CaF 2 nanocrystals and nitroaromatics leads to reduction in the fluorescence intensity by inhibiting the energy transfer from 4-MBA to Tb 3+ ion in CaF 2 nanocrystals.

The occurrence of plastic particles in aquatic environment has led to enormous concern in the past few years. The sorption behaviors of harmful organic compounds by plastic particles can increase their concentrations by several orders of magnitude influencing their global transport in the marine environment. Five types of mesoplastics (5-20 mm) and five types of microplastics (< 5 mm) were selected to investigate the sorption behaviors of three typical organic compounds (phenanthrene, nitrobenzene, and naphthalene). For phenanthrene, most microplastics have stronger sorption ability than that of mesoplastics due to the higher specific surface area (SSA). However, the sorption ability of nitrobenzene on low-density polyethylene (LDPE) mesoplastics was higher than that on LDPE microplastics, and the sorption ability of naphthalene on polyvinyl chloride (PVC) mesoplastics was higher than that on PVC microplastics, which were attributed to the presence of functional groups on the surface of mesoplastics, induced by adding slip agents, lubricant, plasticizer, stabilizer, etc. during film production. Talcum-filled polypropylene (PP) microplastics had strongest sorption ability to nitrobenzene and naphthalene due to the presence of talcum and high SSA. For unmodified microplastics, the sorption abilities of phenanthrene, nitrobenzene, and naphthalene were all followed the order of high-density polyethylene (HDPE) > polystyrene (PS) > LDPE > PVC after SSA normalization. Thus, SSA and the functional groups on the surface of plastic particles should be considered when the sorption behaviors of harmful organic compounds on plastic particles are studied.

A novel Shewanella@graphene core-shell composite material was fabricated following one-step bioreduction of graphene oxide (GO) by Shewanella putrefaciens CN-32. The surface properties and microstructures were characterized by FTIR, TG-DTG, SEM and TEM, which indicate that GO was effectively reduced to rGO and subsequently loaded onto the outer surface of the microbe Shewanella. CLSM was performed to get insight into the growth of the bacteria after core-shell materials formation. The reduction properties of Shewanella@graphene materials were evaluated using nitrobenzene, a representative model pollutant, as an electron acceptor. The reduction efficiency of Shewanella was improved by strengthening the contact among electron donors, electron shuttles and electron acceptors and changed with the proportions of core-shell materials. The optimal proportion of the core-shell material was OD600 = 0.6:GO = 10 mg/L, which was enhanced by the wrapped rGO and improved adsorption capability. The reduction rate was elevated 30% in comparison with pure Shewanella. In addition, the core-shell material exhibited a favorable recycling performance, which can be reused for at least five times. Facile fabrication and enhanced reduction performance of Shewanella@graphene core-shell composite endows this material with considerable potential in environmental remediation., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The first tetrakis-tetrathiafulvalene-calix[4]pyrrole (TTF-C[4]P) was reported in 2004. Early on it and related π-extended TTF-C[4]Ps were found to function as both anion receptors and as hosts for planar electron deficient neutral guests, including nitroaromatic explosives. Anion binding was found to occur with a 1 : 1 binding stoichiometry and to stabilise the cone C[4]P conformation, whereas planar electron deficient guests were bound in a cooperative 1 : 2 fashion to the 1,3-alternate conformer. Addition of strongly complexing anions was found to trigger release of the electron deficient guests concurrent with a conformational change to the cone form. Subsequent studies led to the discovery of anion-induced complexation with C60, and the finding that the resulting complexes would support fast photoinduced electron transfer events. Synthetic advances then led to the preparation of nonsymmetric TTF-C[4]Ps where a single moiety organises the receptor in either the 1,3-alternate conformation or the partial cone conformation, thus modifying both selectivity and sensitivity. TTF-C[4]P-based stimulus responsive systems, that rely on anions and cations as controlling inputs, have also been developed and studied in recent years. This review provides a summary of TTF-C[4]P-related chemistry.

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and perchlorate (ClO 4 - ) are common, and often co-mingled, contaminants at military ranges worldwide. This project investigated the feasibility of using a passive emulsified oil biobarrier plus a slow release pH buffering reagent to remediate RDX, HMX, and ClO 4 - in a low pH aquifer at an active range. A 33 m biobarrier was emplaced perpendicular to the contaminant plumes, and dissolved explosives, perchlorate, and other relevant parameters were monitored. The pH increased and the DO and ORP decreased after emulsified oil injection, leading to >90% reductions in perchlorate, RDX, and HMX compared to upgradient groundwater. Some nitroso breakdown products were observed immediately downstream of the barrier, but generally decreased to below detection limits farther downgradient. First-order rate constants of approximately 0.1/d were obtained for all three contaminants. Dissolved metals (including As) also increased in the wells immediately adjacent to the barrier, but attenuated as the plume re-aerated in downgradient areas. Biobarrier installation and sampling were performed during scheduled range downtime and had no impacts to ongoing range activities. The field trial suggests that an emulsified oil biobarrier with pH buffering can be a viable alternative to remove explosives and perchlorate from shallow groundwater on active ranges., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A quick, easy, cheap, effective, rugged, and safe extraction approach and gas chromatography/tandem mass spectrometry with programmed temperature vaporization sampling technology were used to determine fungicide quintozene and its hazardous impurity hexachlorobenzene (HCB) in Panax notoginseng root, which is commonly used as a rare traditional Chinese medicine worldwide. The mean recoveries were in the ranges of 94-125 and 84-119% for quintozene and HCB with relative standard deviations of 6.2-16.1% at three concentrations: 0.01, 0.1 and 1 mg kg -1 . Heavy metals arsenic, cadmium, copper and lead were simultaneously detected by an inductively coupled plasma-mass spectrometry approach after digestion with nitric acid. The above methods were used to analyze 50 samples of P. notoginseng roots collected at markets and planting bases from the special local producing areas, namely, Honghe, Kunming and Wenshan in Yunnan province, China. Quintozene and HCB in root samples were determined at <0.0015-1.50 and <0.0015-0.125 mg kg -1 . In the 50 samples, 60, 16, 56, 2 and 6% exceeded the maximum permissible levels in medicinal plants (WM/T2-2004) for quintozene, arsenic, cadmium, lead and copper. The results showed that the method is robust and suitable for measuring quintozene, its hazardous impurity and heavy metals in P. notoginseng roots., (© 2018 John Wiley & Sons, Ltd.)

Nitrobenzene, a toxic nitroaromatic, a feedstock compound to the production of many commercially relevant chemicals were photoelectrocatalytically reduced into aniline on a photoelectrode comprised by a bismuth-doped CuGaS 2 nanocrystallyne thin films on molybdenum. The activity of the photoelectrodes were compared to the reaction performed on undoped-CuGaS 2 films, and they were carried out under illumination with an applied bias potential at 0.9 V. Aniline was highly selectively obtained with 83% of conversion for reaction times of 100 min when using Bi-doped CuGaS 2 , representing higher conversion of nitrobenzene and yield to aniline than the undoped photoelectrode. The catalytic performance of the doped films remained stable for a set of 5 consecutive experiments. These results indicate Bi-doped CuGaS 2 as a promising material to be applied in the photoelectrocatalytic reduction of nitrobenzene into aniline through the direct pathway mechanism, using solar light illumination., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Detection of explosive residues in soil and postblast debris is an important issue in sensor design for environmental and criminological purposes. An easy-to-use and low-cost gold nanoparticle (AuNP)-based colorimetric sensor was developed for the determination of nitroaromatic explosives, i.e., trinitrotoluene (TNT) and tetryl, capable of analyte detection at picomolar (pM) levels. The sensor nanoparticles were synthesized by functionalizing the negatively charged thioglycolic acid (TGA)-modified AuNPs with positively charged (±)- trans-1,2-diaminocyclohexane (DACH) at a carefully calculated pH. The working principle of the sensor is charge-transfer (CT) interaction between the electron-rich free amino (-NH 2 ) group of DACH and the electron-deficient -NO 2 groups of TNT/tetryl, added to possible nanoparticle agglomerization via electrostatic interaction of TNT-Meisenheimer anions with more than one cationic DACH-modified AuNP. The limit of detection (LOD) and limit of quantification (LOQ) of the sensor were 1.76 pM and 5.87 pM for TNT and 1.74 pM and 5.80 pM for tetryl, respectively. TNT, tetryl, and tetrytol, extracted from a nitroaromatic explosive-contaminated soil sample, were determined with the proposed sensor, yielding good recoveries. The sensor could be selectively applied to various mixtures of TNT with common energetic materials such as RDX, HMX, and PETN. Additionally, common soil ions (Cl - , NO 3 - , SO 4 2- , K + , Mg 2+ , Ca 2+ , Cu 2+ , Fe 2+ , Fe 3+ , and Al 3+ ) as well as detergents, sugar, sweeteners, acetylsalicylic acid (aspirin), caffeine, and paracetamol-based painkiller drugs, which may be used as camouflage materials for explosives, either had no adverse effects or removable interferences on the detection method. The developed method was statistically validated against a GC-MS literature method.

The aim of this study is to evaluate the micropollutant removal capacity of a 275 nm light-emitting diode (LED)-UV/chlorine system. The sulfamethoxazole, ibuprofen, and nitrobenzene removal efficiencies of this system were compared with those of a conventional 254 nm low-pressure (LP)-UV system as a function of the UV dose. In a direct photolysis system, the photon reactivity of sulfamethoxazole is higher than that of nitrobenzene and ibuprofen at both wavelengths. The molar absorption coefficients and quantum yields of each micropollutant were as follows: sulfamethoxazole (ε SMX, 275 nm protonated  = 17,527 M -1  cm -1 , Φ SMX, 275 nm protonated  = 0.239, ε SMX, 275 nm deprotonated  = 8430 M -1  cm -1 , and Φ SMX, 275 nm deprotonated  = 0.026), nitrobenzene (ε NB, 275 nm  = 7176 M -1  cm -1 and Φ NB, 275 nm  = 0.057), and ibuprofen (ε NB, 275 nm  = 200 M -1  cm -1 and Φ IBF, 275 nm  = 0.067). The photon reactivity of chlorine species, i.e., HOCl and OCl-, were determined at 275 nm (ε HOCl, 275 nm  = 28 M -1  cm -1 , Φ HOCl, 275 nm  = 1.97, ε OCl-, 275 nm  = 245 M -1  cm -1 , and Φ OCl-, 275 nm  = 0.8), which indicate that the decomposition rate of OCl - is higher and that of HOCl is lower by 275 nm photolysis than that by 254 nm photolysis (ε HOCl, 254 nm  = 60 M -1  cm -1 , Φ HOCl, 254 nm  = 1.46, ε OCl-, 254 nm  = 58 M -1  cm -1 , and Φ OCl-, 254 nm  = 1.11). In the UV/chlorine system, the removal rates of ibuprofen and nitrobenzene were increased by the formation of OH and reactive chlorine species. The 275-nm LED-UV/chlorine system has higher radical yields at pH 7 and 8 than the 254 nm LP-UV/chlorine system., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The rotating packed bed (RPB) as a continuous flow reactor performs very well in degradation of nitrobenzene wastewater. In this study, acidic nitrobenzene wastewater was degraded using ozone (O 3 ) combined with hydrogen peroxide and titanium ions (Ti(IV)/H 2 O 2 /O 3 ) or using only H 2 O 2 /O 3 in a RPB. The degradation efficiency of nitrobenzene by Ti(IV)/H 2 O 2 /O 3 is roughly 16.84% higher than that by H 2 O 2 /O 3 , and it reaches as high as 94.64% in 30 min at a H 2 O 2 /O 3 molar ratio of 0.48. It is also found that the degradation efficiency of nitrobenzene is significantly affected by the high gravity factor, H 2 O 2 /O 3 molar ratio, and Ti(IV) concentration, and it reaches a maximum at a high gravity factor of 40, a Ti(IV) concentration of 0.50 mmol/L, a pH of 4.0, a H 2 O 2 /O 3 molar ratio of 0.48, a liquid flow rate of 120 L/h, and an initial nitrobenzene concentration of 1.22 mmol/L. Both direct ozonation and indirect ozonation are involved in the reaction of O 3 with organic pollutants. The indirect ozonation due to the addition of different amounts of tert-butanol (·OH scavenger) in the system accounts for 84.31% of the degradation efficiency of nitrobenzene, indicating that the nitrobenzene is dominantly oxidized by ·OH generated in the RPB-Ti(IV)/H 2 O 2 /O 3 process. Furthermore, the possible oxidative degradation mechanisms are also proposed to better understand the role of RPB in the removal of pollutants. Graphical abstract ᅟ.

Nitrobenzene, a potentially harmful compound found in tobacco smoke, has been largely excluded from prior analysis due to difficulties with quantification. Quantifying harmful compounds in cigarette smoke is useful to compare products, to examine the impact of design parameters on delivery, and to help estimate exposures. A sensitive high-throughput method has been developed for quantifying nitrobenzene in machine-generated mainstream cigarette smoke using isotope dilution gas chromatography-tandem mass spectrometry (ID-GC-MS/MS). This method has sufficient sensitivity to measure vapor phase nitrobenzene concentrations in the low nanogram range, with a 418 pg/cig method limit of detection. Precision estimates from two quality control cigarette products resulted in percent relative standard deviations of 11.5% and 14.9%; product variability estimates from 13 cigarette products resulted in percent relative standard deviations ranging from 2.8% to 16.9%. Nitrobenzene in the machine-generated, mainstream smoke from 15 cigarette products are reported and range from 18 to 38 ng/cig under the Health Canada Intense smoking regimen., (Published by Elsevier B.V.)

Flutolanil and pentachloronitrobenzene (PCNB) are fungicides used to control or suppress foliar and soil borne diseases in turf and ornamental crops. On golf courses, sports fields, sod farms and commercial lawns these fungicides are used as preventive treatments to combat snow mold, brown patch and fairy ring. Depending on the aquatic organism, flultolanil and PCNB are considered to be moderately to highly toxic. Therefore runoff or drift from treated areas may be hazardous to organisms in adjacent aquatic sites. This research compared the transport of flutolanil and PCNB with runoff from turfgrass managed as a golf course fairway. The quantity of fungicide transported with runoff and observations reported with the chemographs followed trends in agreement with the chemical properties of the compounds. Overall, we observed the rate of transport for flutolanil was greater than PCNB, which contributed to the more than 12 times larger load (µg/m 2 ) of flutolanil transported off-site at the conclusion of the simulated storm runoff. A better understanding of the off-site transport of pesticides with runoff is needed to make informed decisions on management practices to reduce potential adverse effects on non-target organisms, as well as maintain control of targeted pests in the area of application. In addition, data obtained with this research can be used in model simulations to predict nonpoint source pollution potentials beyond experimental conditions., (Copyright © 2018. Published by Elsevier Inc.)

Since nitroaromatic- and nitramine-type energetic materials, mostly arising from military activities, are persistent pollutants in soil and groundwater, on-site sensing of these hazardous chemicals has gained importance. A novel electrochemical sensor was designed for detecting nitroaromatic- and nitramine-type energetic materials, relying on gold nanoparticles (Au nano ), modified glassy carbon (GC) electrode coated with nitro-energetic memory-poly(carbazole-aniline) copolymer (Cz- co-ANI) film (e.g., TNT memory-GC/P(Cz- co-ANI)-Au nano modified electrode). Current was recorded against concentration to build the calibration curves that were found to be linear within the range of 100-1000 μg L -1 for 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT): 50-1000 μg L -1 for 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). The corresponding limits of detection were 25 μg L -1 for TNT, 30 μg L -1 for DNT, and 10 μg L -1 for both RDX and HMX, using nitro-energetic memory-GC/P(Cz- co-ANI)-Au nano electrodes. These electrodes were used separately, and specific determinations were made in various mixtures of nitro-energetic materials. The developed method could be efficiently used in electroanalyzing nitroaromatics and nitramines in military explosives (i.e., comp B, octol, and comp A5). The sensor electrodes were specific for the tested nitro-energetic compounds and did not respond to paracetamol-caffeine-based analgesic drug, acetylsalicylic acid (aspirin), sweetener, and sugar that can be used as camouflage materials in passenger belongings. The developed method was statistically validated against the standard LC-MS reference method in contaminated clay soil samples containing TNT and RDX explosives.

In this study a novel iron-based reducing agent of highly effective reduction toward nitrobenzene (NB) was obtained by pretreating zero valent iron (ZVI) with H 2 O 2 /HCl. During the H 2 O 2 /HCl pretreatment, ZVI undergoes an intensive corrosion process with formation of various reducing corrosion products (e.g., Fe 2+ , ferrous oxides/hydroxides, Fe 3 O 4 ), yielding a synergetic system (prtZVI) including liquid, suspensions and solid phase. The pretreatment process remarkably enhances the reductive performance of ZVI, where a rapid reduction of NB (200 mg L -1 ) in the prtZVI suspension was accomplished in a broad pH range (3-9) and at low dosage. Nitrosobenzene and phenylhydroxylamine are identified as the intermediates for NB reduction with the end-product of aniline. Compared with the virgin ZVI as well as another nanosized ZVI, the prtZVI system exhibits much higher electron efficiency for NB reduction as well as higher utilization ratio of Fe 0 . A rapid reduction of various nitroaromatics in an actual pharmaceutical wastewater further demonstrated the feasibility of the prtZVI system in real wastewater treatment., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Water quality criteria (WQC) are considered to be an effective management tool for protecting aquatic environments. To derive site-specific WQC for an area, local data based on local species are essential to improve the applicability of WQC derived. Due to the paucity of local fish data available for the development of site-specific WQC for the Liao River, China, four local and widespread fishes (Pseudorasbora parva， Abbottina liaoningensis, Ctenogobius giurinus, and Misgurnus anguillicaudatus) were chosen to test their sensitivities to ammonia, cadmium and nitrobenzene. These compounds are common and regularly-measured pollutants in Chinese rivers. In addition to the published data for species resident in the Liao River, site-specific WQC for the three chemicals were derived using both a log-logistic species sensitivity distribution (SSD) and the method recommended by the USEPA, in line with current best practice, which were then compared with Chinese national WQC. It was found that A. liaoningensis was the most sensitive, followed, in order, by P. parva, C. giurinus and M. anguillicaudatus was the least sensitive, and this trend was the same to all three chemicals tested. When comparing the SSD derived solely from previously-published data with that including our data on local fish, there were significant differences identified among parameters describing the SSD curves for ammonia and nitrobenzene and significant differences were detected for site-specific WQC derived for all of the three chemicals. Based on the dataset with local fish data taxa, site-specific WQC of Liao River for ammonia, cadmium, and nitrobenzene were derived to be 20.53mg/L (at a pH of 7.0 and temperature of 20°C), 3.76μg/L (at a hardness of 100mg/L CaCO 3 ), and 0.49mg/L, respectively. Using the same deriving method for each chemical, the national Chinese WQC were higher than site-specific WQC derived in this study for ammonia (national WQC of 25.16mg/L) and nitrobenzene (national WQC of 0.57mg/L), while the national WQC for cadmium was lower (national WQC of 1.81μg/L). These results indicated that published data can be helpful for use when deriving site-specific WQC but that there were differences between site-specific and national WQC which may lead to either over- or under-protection depending on the pollutant if national WQC were used as the basis for the water management of specific river systems, like the Liao River., (Copyright © 2017. Published by Elsevier Inc.)

This paper introduces a novel approach to enhance the strains' biodegradation of 4-chloronitrobenzene by utilizing the synergistic effect of the organic reductant mannitol and the substrate beef extraction. Our results demonstrate that 4-chloronitrobenzene could not be an available nitrogen source to support target strains' growth, which induced the limited 4-chloronitrobenzene biodegradation. In addition, the organic reducing agent and substrate had a better synergistic effect than inorganic reducing agent and substrate to enhance the strains' 4-chloronitrobenzene cometabolic biodegradation. Employing the synergistic effect of the optimal mixture (mannitol and beef extraction), the biodegradation rates of 50mgL -1 4-chloronitrobenzene by seven of the ten target strains were enhanced up to 100% from previous removals of no more than 19.1% after 7days. Three of the strains could even completely degrade 100mgL -1 4-chloronitrobenzene while five strains degraded over 91.4%. The method has good potential to enhance bioremediation of various 4-Chloronitrobenzene-contaminated environments as mannitol and beef extraction are non-toxic to the environment., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The toxicity of a mixture depends not only on the mixture concentration level but also on the mixture ratio. For a multiple-component mixture (MCM) system with a definite chemical composition, the mixture toxicity can be predicted only if the global concentration additivity (GCA) is validated. The so-called GCA means that the toxicity of any mixture in the MCM system is the concentration additive, regardless of what its mixture ratio and concentration level. However, many mixture toxicity reports have usually employed one mixture ratio (such as the EC 50 ratio), the equivalent effect concentration ratio (EECR) design, to specify several mixtures. EECR mixtures cannot simulate the concentration diversity and mixture ratio diversity of mixtures in the real environment, and it is impossible to validate the GCA. Therefore, in this paper, the uniform design ray (UD-Ray) was used to select nine mixture ratios (rays) in the mixture system of five nitrobenzene derivatives (NBDs). The representative UD-Ray mixtures can effectively and rationally describe the diversity in the NBD mixture system. The toxicities of the mixtures to Vibrio qinghaiensis sp.-Q67 were determined by the microplate toxicity analysis (MTA). For each UD-Ray mixture, the concentration addition (CA) model was used to validate whether the mixture toxicity is additive. All of the UD-Ray mixtures of five NBDs are global concentration additive. Afterwards, the CA is employed to predict the toxicities of the external mixtures from three EECR mixture rays with the NOEC, EC 30 , and EC 70 ratios. The predictive toxicities are in good agreement with the experimental toxicities, which testifies to the predictability of the mixture toxicity of the NBDs., (Copyright © 2017. Published by Elsevier Inc.)

Surrogate-based simulation-optimization technique is an effective approach for optimizing the surfactant enhanced aquifer remediation (SEAR) strategy for clearing DNAPLs. The performance of the surrogate model, which is used to replace the simulation model for the aim of reducing computation burden, is the key of corresponding researches. However, previous researches are generally based on a stand-alone surrogate model, and rarely make efforts to improve the approximation accuracy of the surrogate model to the simulation model sufficiently by combining various methods. In this regard, we present set pair analysis (SPA) as a new method to build ensemble surrogate (ES) model, and conducted a comparative research to select a better ES modeling pattern for the SEAR strategy optimization problems. Surrogate models were developed using radial basis function artificial neural network (RBFANN), support vector regression (SVR), and Kriging. One ES model is assembling RBFANN model, SVR model, and Kriging model using set pair weights according their performance, and the other is assembling several Kriging (the best surrogate modeling method of three) models built with different training sample datasets. Finally, an optimization model, in which the ES model was embedded, was established to obtain the optimal remediation strategy. The results showed the residuals of the outputs between the best ES model and simulation model for 100 testing samples were lower than 1.5%. Using an ES model instead of the simulation model was critical for considerably reducing the computation time of simulation-optimization process and maintaining high computation accuracy simultaneously., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Nitramines are potentially carcinogens that form from the amines used in post-combustion CO 2 capture (PCCC). The soil sorption characteristics of monoethanol (MEA)- and dimethyl (DMA)-nitramines have been assessed using a batch experimental setup, and defined indirectly by measuring loss of nitramine (LC-MS/MS) from the aqueous phase (0.01 M CaCl 2 and 0.1% NaN 3 ) after equilibrium had been established with the soil (24 h). Nitramine soil sorption was found to be strongly dependent on the content of organic matter in the soil (r 2 = 0.72 and 0.95, p < 0.05). Soil sorption of MEA-nitramine was further influenced by the quality of the organic matter (Abs 254 nm , r 2 = 0.93, p < 0.05). This is hypothesized to be due to the hydroxyl group on the MEA-nitramine, capable of forming hydrogen bonds with acidic functional groups on the soil organic matter. Estimated organic carbon normalized soil-water distribution coefficients (K OC ) are relatively low, and within the same range as for simple amines. Nevertheless, considering the high content of organic matter commonly found in the top layer of a forest soil, this is where most of the nitramines will be retained. Presented data can be used to estimate final concentrations of nitramines in the environment following emissions from amine-based PCCC plants.

Chlorhexidine gluconate is used to prevent the accumulation of dental plaque and gingivitis, infection of the surgical site, and ventilator-associated pneumonia in maxillofacial surgery, but it is not clear whether the metabolites of chlorhexidine are detectable in the patient's saliva at clinically relevant concentrations. Forty-three patients who had orofacial operations were randomised to use a 0.2% chlorhexidine gluconate (n=23), or an octenidine-based, chlorhexidine-free (n=20), mouthwash once preoperatively and three times daily for five postoperative days. After the first, 8.7 (23.3) mg/L chlorhexidine (0.7%-2.5% of the total amount used) was measured in saliva. The concentration increased to 15.2 (6.2) mg/L after the second rinse (first postoperative day), and peaked at 29.4 (11.2) mg/L on the fourth postoperative day. It remained detectable for up to 12hours after the last one, but was not detectable in serum or urine at any time. The potentially carcinogenic metabolite p-chloroaniline was detectable in saliva at higher concentrations in the chlorhexidine group (0.55mg/L) than the octenidine group (0.21mg/L), and p-chloronitrobenzene was detected in both groups in only minimal concentrations (0.001-0.21mg/L). Chlorhexidine gluconate mouthwashes do increase the concentration of p-chloroaniline, but a single use seems to be safe. Whether prolonged exposure over many years may have carcinogenic potential is still not clear. Based on the hitherto unknown kinetics of p-chloroaniline in saliva, the recent recommendation of the Federal Drug Administration (FDA) in the USA to limit the use of a chlorhexidine gluconate mouthwash to a maximum of six months seems to be justified., (Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. All rights reserved.)

The efficacies of catalyzed H2O2, activated persulfate, and catalyzed H2O2-persulfate processes for the degradation of ortho-nitrochlorobenzene (o-NCB) in soil were investigated. The application of catalyzed H2O2-persulfate process was promising, and after a careful adjustment of oxidants and activator doses, it demonstrated a considerable improvement in o-NCB degradation compared with activated persulfate process and catalyzed H2O2 process. The degradation of o-NCB in catalyzed H2O2-persulfate process was obviously influenced by the concentration of persulfate and H2O2, the molar ratio between persulfate and H2O2, the concentration of o-NCB, and initial pH. Degradation of o-NCB was obviously inhibited by the addition of tert-butyl alcohol, methanol, and phenol, suggesting that nitrobenzene was dominantly oxidized by HO· and SO4 (-)· generated in the catalyzed H2O2-persulfate process. The results from these studies demonstrated that the natural iron species present in soil could effectively facilitate the degradation of organic pollutants in the presence of H2O2 and persulfate.

On-spot monitoring of threat agents needs high sensitive instrument. In this study, a low-pressure photoionization mass spectrometer (LPPI-MS) was employed to detect trace amounts of vapor-phase explosives and chemical warfare agent mimetics under ambient conditions. Under 10-s detection time, the limits of detection of 2,4-dinitrotoluene, nitrotoluene, nitrobenzene, and dimethyl methyl phosphonate were 30, 0.5, 4, and 1 parts per trillion by volume, respectively. As compared to those obtained previously with PI mass spectrometric techniques, an improvement of 3-4 orders of magnitude was achieved. This study indicates that LPPI-MS will open new opportunities for the sensitive detection of explosives and chemical warfare agents., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This study investigated the effects of varying nitrobenzene (NB) loadings via increasing flow rate or influent NB concentration mode on the removal efficiency in zero-valent iron (ZVI) columns sterilized (abiotic) or preloaded with acclimated microorganisms (biotic). It was shown that physical sequestration via adsorption/co-precipitation and reductive transformation of NB to aniline (AN) were the two major mechanisms for the NB removal in both abiotic and biotic ZVI columns. The NB removal efficiency decreased in both columns as the flow rate increased from 0.25 to 1.0mLmin(-1) whereas the AN recovery increased accordingly, with relatively high AN recovery observed at the flow rate of 1.0mLmin(-1). At the constant flow rate of 0.5mLmin(-1), increasing influent NB concentration from 80 to 400μmolL(-1) resulted in decreasing of the overall NB removal efficiency from 79.5 to 48.6% in the abiotic column and from 85.6 to 62.5% in the biotic column. The results also showed that the sequestration capacity and chemical reduction capacity were respectively 72% and 157.6% higher in the biotic column than in the abiotic column at the same tested hydraulic conditions and NB loadings. The optimal flow rates and influent NB concentrations were at 0.5mLmin(-1) and 80μmolL(-1) for the abiotic column and 2.0mLmin-1 and 240μmolL(-1) for the biotic column, respectively. This study indicated that microorganisms not only enhanced overall reduction of NB, but also facilitated NB sequestration within the porous media and that the optimal loading conditions for overall removal, sequestration, and reduction of NB may be different. Optimal operation conditions should be found for preferred sequestration or transformation (or both) of the target contaminants to meet different goals of groundwater remediation with the ZVI-PRB systems., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Halonitrobenzenes (HNBs) are a class of molecules that are highly toxic to human health and the ecological environment. Thus, effective and efficient approaches capable of monitoring and detecting HNBs are greatly desired. We report herein a simple and sensitive method for the detection of HNBs. The detection was based on the indium tin oxide (ITO) electrodes modified with a binary assembly of highly ordered surfactant micelles (OSMs) and silica mesochannels (SMs). The SMs have a diameter of 2-3 nm and a vertical orientation, which provide a hard support to stabilize soft OSMs. Moreover, each OSM consists of a hydrophobic core due to the organized assembly of surfactant hydrocarbon chains, which can selectively extract and concentrate lipophilic HNBs from aqueous media, allow their transport to the underlying ITO electrode surface and therein their detection by voltammetry. As a proof-of-concept experiment, 1-chloro-3-nitrobenzene, 1-chloro-4-nitrobenzene, 1-bromo-4-nitrobenzene and 2,4-dinitrobromobenzene were analyzed in aqueous solutions. A simple and fast detection was achieved in all cases, with a wide linear dynamic range, a high sensitivity and a low limit of detection at the ppb level. Apart from the extraction ability, the OSMs also prohibited the access of and surface contamination by unwanted substances, showing excellent anti-fouling and anti-interference power. Indeed, as we demonstrated, the sensor could be employed for direct electrochemical detection of HNBs in complex samples, such as lake water and soil dispersion, without any pre-treatment, indicating its potential usefulness in practical analysis.

p-Fluoronitrobenzene (p-FNB) was degraded in a novel three dimensional bioelectrochemical system (3D BES) and potentially utilized as carbon source for achieving both nitrate (NO3(-)−N) and Cr(VI) reduction. For single NO3(-)−N and Cr(VI) removal, 200 mg L(-1) NO3(-)−N and 100 mg L(-1) Cr(VI) could be almost completely converted to N2 and Cr(III) at current 50 mA. For single p-FNB degradation, 100 mg L(-1) p-FNB was completely degraded at current 50 mA. The critical current for defluorination was 40 mA, and the intermediate product p-fluoroaniline (p-FA) tended to decrease when current was higher than 40 mA. When NO3(-)−N, Cr(VI), and p-FNB were both coexisted in this system, the average NO3(-)−N, Cr(VI), and p-FNB removal efficiencies slightly decreased with addition of carbon source. Without carbon source, NO3(-)−N and Cr(VI) removal rates reached 34.45% and 41.38% with 91.02% p-FNB degradation, proving that NO3(-)−N and Cr(VI) could be reduced by degrading p-FNB in the BES., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Intermittent aeration and addition of glucose were applied to horizontal subsurface flow constructed wetlands in order to investigate the effect on pathways of nitrobenzene (NB) degradation and interactions with microbial nitrogen and sulphur transformations. The experiment was carried out in three phases A, B and C consisting of different NB loading and glucose dosing. For each phase, the effect of aeration was assessed by intermittently aerating one wetland and leaving one unaerated. Regardless of whether or not the wetland was aerated, at an influent NB concentration of 140 mg/L, both wetlands significantly reduced NB to less than 2 mg/L, a reduction efficiency of 98%. However, once the influent NB concentration was increased to 280 mg/L, the aerated wetland had a higher removal performance 82% compared to that of the unaerated wetland 71%. Addition of glucose further intensified the NB removal to 95% in the aerated wetlands and 92% in the unaerated. Aeration of wetlands enhanced NB degradation, but also resulted in higher NB volatilization of 6 mg m(-2) d(-1). The detected high concentration of sulphide 20-60 mg/L in the unaerated wetland gave a strong indication that NB may act as an electron donor to sulphate-reducing bacteria, but this should be further investigated. Aeration positively improved NB removal in constructed wetlands, but resulted in higher NB volatilization. Glucose addition induced co-metabolism to enhance NB degradation., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Synchronized discharge ionization (SDI) was previously developed for hand-held mass spectrometers with discontinuous atmospheric pressure interfaces. The function of SDI has been demonstrated for analysis of volatile organic compounds in air at high sensitivity, which is attributed to the fact that ions were produced next to the ion trap mass analyzer inside the vacuum manifold. In this study, a simple sampling device was designed and fitted to a hand-held mass spectrometer to characterize its potential in direct analysis of low-volatility chemicals on surfaces. Nine chemicals of vapor pressures ranging from 10(-4) to 10(-8) Torr (at room temperature), including pesticides, illicit drugs, and explosives, were selected to evaluate and demonstrate the analytical capability of the designed system. Compounds of vapor pressures below 10(-7) Torr, such as tetryl, cocaine, and tetrahydrocannabinol (THC), have been successfully detected. Direct analysis of pesticides from fruit and explosives from a large surface area has also been demonstrated. Tandem mass analysis was performed, which helped to confirm the analyte identity as well as to improve the signal-to-noise ratio (S/N).

This paper describes the fate of a nitrobenzene-degrading bacterium, Klebsiella oxytoca NBA-1, which was isolated from a pharmaceutical wastewater treatment facility. The 90-day survivability of strain NBA-1 after exposure to sludge under anaerobic and aerobic conditions was investigated. The bacterium was inoculated into sludge amended with glucose and p-chloronitrobenzene (p-CNB) to compare the bacterial community variations between the modified sludge and nitrobenzene amendment. The results showed that glucose had no obvious effect on nitrobenzene biodegradation in the co-metabolism process, regardless of the presence/absence of oxygen. When p-CNB was added under anaerobic conditions, the biodegradation rate of nitrobenzene remained unchanged although p-CNB inhibited the production of aniline. The diversity of the microbial community increased and NBA-1 continued to be one of the dominant strains. Under aerobic conditions, the degradation rate of both nitrobenzene and p-CNB was only 20% of that under anaerobic conditions. p-CNB had a toxic effect on the microorganisms in the sludge so that most of the DGGE (denaturing gradient gel electrophoresis) bands, including that of NBA-1, began to disappear under aerobic conditions after 90days of exposure. These data show that the bacterial community was stable under anaerobic conditions and the microorganisms, including NBA-1, were more resistant to the adverse environment., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A series of uranyl-organic frameworks (UOFs), {[(UO2)2(H2TTHA)(H2O)]·4,4'-bipy·2H2O}n (1), {[(UO2)3(TTHA)(H2O)3]}n (2), and {[(UO2)5(TTHA) (HTTHA)(H2O)3]·H3O}n (3), have been obtained by the hydrothermal reaction of uranyl acetate with a flexible hexapodal ligand (1,3,5-triazine-2,4,6-triamine hexaacetic acid, H6TTHA). These compounds exhibited three distinct 3D self-assembly architectures as a function of pH by single-crystal structural analysis, although the used ligand was the same in each reaction. Surprisingly, all of the coordination modes of the H6TTHA ligand in this work are first discovered. Furthermore, the photoluminescent results showed that these compounds displayed high-sensitivity luminescent sensing functions for nitrobenzene. Additionally, the surface photovoltage spectroscopy and electric-field-induced surface photovoltage spectroscopy showed that compounds 1-3 could behave as p-type semiconductors.

Formation of nitrosamines and nitramines from reactions between flue gas NOx and the amines used in CO2 capture units has arisen as a significant concern. Washwater scrubbers can capture nitrosamines and nitramines. They can also capture amines, preventing formation of nitrosamines and nitramines downwind by amine reactions with ambient NOx. The continuous application of UV alone, or a combination of UV and ozone to the return line of a washwater treatment unit was evaluated to control the accumulation of nitrosamines, nitramines and amines in a laboratory-scale washwater unit. With model secondary amine solvents ranging from nonvolatile diethanolamine to volatile morpholine, application of 272-537 mJ/cm(2) UV incident fluence alone reduced the accumulation of nitrosamines and nitramines by approximately an order of magnitude. Modeling indicated that the gains achieved by UV treatment should increase over time, because UV treatment converts the time dependence of nitrosamine accumulation from a quadratic to a linear function. Ozone (21 mg/L) maintained low steady-state concentrations of amines in the washwater. While modeling indicated that more than 80% of nitrosamine accumulation in the washwater was associated with reaction of washwater amines with residual NOx, a reduction in nitrosamine accumulation rates due to ozone oxidation of amines was not fully realized because the ozonation products of amines reduced nitrosamine photolysis rates by competing for photons.

A novel portable device for fast and sensitive analysis of explosives in environmental samples is presented. The developed system consists of miniaturized microcolumn liquid chromatograph, photolytic converter and chemiluminescence detector. The device is able to determine selectively nitramine- and nitroester- and most of nitroaromates-based explosives as well as inorganic nitrates at trace concentrations in water or soil extracts in less than 8 min. The device allows to analyze various environmental samples such as soils or water materials without previous preconcentration. Because of internal power supply, the device ensures 12h of continuous operation. Limits of detection of compounds of interest are in the range of concentrations from 5.0 × 10(-9)M to 8.0 × 10(-5)M for a signal-to-noise ratio of 3. Limits of quantification are in the range of concentrations from 1.7 × 10(-8)M to 2.7 × 10(-4)M for a signal-to-noise ratio of 10. The repeatability of the method (RSD=2.9-5.6%) was determined by repeated injections (n=10) of the standard samples during 4h., (Copyright © 2015 Elsevier B.V. All rights reserved.)

We developed an efficient one-pot strategy for the preparation of hydrophilic amine-functionalized nanocomposites by using hydrophobic fluorescence quantum dots ZnS:Mn(2+)@allyl mercaptan (QDs@AM) as building blocks through novel light-induced in situ polymerization. The average size of as-prepared hydrophilic nanocomposites was ∼50 nm, which could be further tuned by varying the concentrations of the monomers. Importantly, these nanocomposites were further utilized for the facile, highly sensitive, and selective detection of nitroaromatics. The linear ranges for 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) lie in 0.01-0.5 μg/mL and 0.05-8.0 μg/mL, respectively, barely interfered with by other nitroaromatics such as 2,4-dinitrotoluene (DNT) and nitrobenzene (NB). Moreover, the novel surface modification method developed here offered a general strategy for fabricating hydrophobic nanocomposites with hydrophilic properties and indicated various potential applications including sensing and imaging.