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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.)

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.)

The present study involves a green synthesis of gold nanoparticles (Au-NPs) using Acacia nilotica twig bark extract at room temperature and trace level detection of one of the hazardous materials, viz. nitrobenzene (NB) that causes Methemoglobinaemia. The synthesis protocol demonstrates that the bioreduction of chloroauric acid leads to the formation of Au-NPs within 10min, suggesting a higher reaction rate than any other chemical methods involved. The obtained Au-NPs have been characterized by UV-vis spectroscopy, X-ray diffraction, transmission electron microscopy, Energy-Dispersive X-ray Spectroscopy and Fourier Transform Infrared Spectroscopy. The electrochemical detection of NB has been investigated at the green synthesized Au-NPs modified glassy carbon electrode by using differential pulse voltammetry (DPV). The Au-NPs modified electrode exhibits excellent reduction ability toward NB compared to unmodified electrode. The developed NB sensor at Au-NPs modified electrode displays a wide linear response from 0.1 to 600μM with high sensitivity of 1.01μAμM(-1)cm(-2) and low limit of detection of 0.016μM. The modified electrode shows exceptional selectivity in the presence of ions, phenolic and biologically coactive compounds. In addition, the Au-NPs modified electrode exhibits an outstanding recovery results toward NB in various real water samples., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A novel bio-reactive capping barrier composed of polysulfone/granular activated carbon (PS/GAC) hybrid membranes immobilized with microorganism was developed for the remediation of nitrobenzene in sediments. The SEM observation demonstrated that all the membranes had a dense top layer and a porous sublayer, this structure can block the transfer of nitrobenzene from sediment to the water and enhance nitrobenzene degradation. Adsorption behaviors of nitrobenzene on membranes showed that the membrane impregnated with GAC had better performance than the pure PS membrane. The values of Kads increased from 4.64 (without GAC) to 6.19 (1:2 GAC). 20mg/L nitrobenzene can be completely degraded by Pseudomonas putida immobilized on membranes. The biodegradation rate of activated carbon-filled membrane system was little higher than that of pure PS membrane system. For remediation experiments, only about 21.7, 28.3 and 43.9% of nitrobenzene in the sediment was removed by the end of the experiments for PS/GAC membrane, sand-alone and sand amended with activated carbon capping systems, respectively. While for PS/GAC+microorganisms capping system, more than 70% of nitrobenzene loss was observed. This demonstrated that nitrobenzene can be effectively removed from contaminated sediments by microbial degradation in the bio-reactive capping system., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A cold-tolerant microbial consortium, which can use nitrobenzene (NB) and aniline (AN) as sole carbon, nitrogen and energy sources, was isolated from an NB and AN contaminated site. Pilot 454 pyrosequencing analysis of the consortium showed that it was mainly made up of Pseudomonas spp. (98%). At 10 °C, the consortium degraded the mixture of 50mg/L NB and 50mg/L AN at a similar rate as those achieved at 20 °C and 30 °C. The biodegradation by-products with different initial NB and AN concentrations at 10 °C were analyzed. Azobenzene, azoxybenzene and acetanilide were observed in NB and AN mixtures degradation. These by-products are generated by the reaction between different intermediates resulting from the NB and AN degradation as well as the parent compounds. To the best of our knowledge, this is the first report confirming the by-products of NB and AN mixture biodegradation by a cold-tolerant microbial consortium., (Copyright © 2013. Published by Elsevier B.V.)

Nitrobenzene at a relatively high concentration was reported to cause an environmental pollution event in Songhua River, China in 2005. The adsorption characteristics of nitrobenzene on the surficial sediments (natural surface coatings) were investigated via a selective extraction--adsorption--statistical analysis method. The experimental results show that the changes in the adsorption potential are not always consistent with the variation of particle structure, suggesting that the effect of removal of some components by extraction or separation procedures on the adsorption potential is much greater than that of variation of particle structure. An additional model analysis indicates that not only organic materials but also Fe oxides, Mn oxides and clay minerals contribute much to the adsorption of nitrobenzene. But the adsorption capacity of Mn oxides on a unit mass basis is the highest, and the lowest for clay minerals except for silicate minerals, implying that the role of organic materials and clay minerals in the solid particles contributed to binding of nitrobenzene is less than that of Fe and Mn oxides, especially the later. The new evidence for the higher adsorption potential of nitrobenzene on the surficial sediments (natural surface coatings) and the more importance of Mn oxides contributed to nitrobenzene adsorption is showed in the present study supposing that the adsorption capacity of solid particles can be divided into several fractions.

A rapid, simple, sensitive and accurate quantitative method has been developed for the determination of eleven nitroaromatic components by solid phase microextraction (SPME) coupled to high performance liquid chromatography (HPLC) with UV detection from aqueous samples. PDMS/DVB resin fiber (60 microm) was used for concurrent extraction of all the analytes from aqueous matrix. Static desorption was carried out in the desorption chamber of SPME-HPLC interface containing mobile phase; methanol:water 43:57 (v/v) with subsequent liquid chromatographic analysis at isocratic flow rate of 1.3 mL/min and detection at 254 nm. A reverse phase amide column (5 microm) was used as a separation medium. The limit of detection (S/N=3) for TNT and Tetryl was found to be 0.35 and 0.54 ng/mL, respectively. Developed method has been applied successfully to the analysis of aqueous samples obtained from environmental and industrial sources like river water, ground water, drinking water and industrial waste water.

Nitration reactions of aromatic compounds are commonly involved in different industrial processes for pharmaceutical, pesticide or military uses. For many years, most of the manufacturing sites used lagooning systems to treat their process effluents. In view of a photocatalytic degradation assay, the wastewater of a lagoon was investigated by using HPLC coupled with mass spectrometry. The wastewater was highly concentrated in RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and two herbicides Dinoterb (2-tert-butyl-4,6-dinitrophenol) and Dinoseb (2-sec-butyl-4,6-dinitrophenol). First of all, an analytical method using solid-phase extraction (SPE) combined with HPLC ESI MS/MS was put in work for identification and titration of RDX, HMX and the two dinitrophenols in a complex natural matrix. Then, the UV/TiO2 treatment was investigated for pollutants removal. Dinitrophenolic compounds were significantly degraded after a 8-h-exposition of the wastewater/TiO2 suspension, whereas RDX and HMX were poorly affected.

A quantitative structure-property relationship (QSPR) study is suggested for the prediction of toxicity (IGC50) of nitrobenzenes. Ab initio theory was used to calculate some quantum chemical descriptors including electrostatic potentials and local charges at each atom, HOMO and LUMO energies, etc. Modeling of the IGC50 of nitrobenzenes as a function of molecular structures was established by means of the least squares support vector machines (LS-SVM). This model was applied for the prediction of the toxicity (IGC50) of nitrobenzenes, which were not in the modeling procedure. The resulted model showed high prediction ability with root mean square error of prediction of 0.0049 for LS-SVM. Results have shown that the introduction of LS-SVM for quantum chemical descriptors drastically enhances the ability of prediction in QSAR studies superior to multiple linear regression and partial least squares.