•ZnO NPs significantly impacts the process of litter decomposition.•Visible light increases the inhibitory effect on pH, fungal sporulation rate, and enzyme activity.•The combined effect reduces the diversity of fungal community presented on litter.ZnO nanoparticles is one of the most used materials in a wide range including antibacterial coating, electronic device, and personal care products. With the development of nanotechnology, ecotoxicology of ZnO nanoparticles has been received increasing attention. To assess the phototoxicity of ZnO nanoparticles in aquatic ecosystem, microcosm experiments were conducted on Populus nigra L. leaf litter decomposition under combined effect of ZnO nanoparticles and visible light radiation. Litter decomposition rate, pH value, extracellular enzyme activity, as well as the relative contributions of fungal community to litter decomposition were studied. Results showed that long-term exposure to ZnO nanoparticles and visible light led to a significant decrease in litter decomposition rate (0.26 m−1 vs 0.45 m-1), and visible light would increase the inhibitory effect (0.24 m-1), which caused significant decrease in pH value of litter cultures, fungal sporulation rate, as well as most extracellular enzyme activities. The phototoxicity of ZnO nanoparticles also showed impacts on fungal community composition, especially on the genus of Varicosporium, whose abundance was significantly and positively related to decomposition rate. In conclusion, our study provides the evidence for negatively effects of ZnO NPs photocatalysis on ecological process of litter decomposition and highlights the contribution of visible light radiation to nanoparticles toxicity in freshwater ecosystems.

We investigated the negative effects of ZnO nanoparticles (NPs) on ecosystem function by focusing on the process of leaf litter decomposition in an aquatic ecosystem. In an indoor microcosm experiment, the influence of 3 different sizes (30, 90 and 200 nm) of ZnO NPs at 100 mg L−1 concentration on Populus nigra L. leaf litter decomposition was determined. Exposure to ZnO NPs significantly inhibited the leaf litter decomposition and a strong inhibitory effect occurred on day 10, 17, and 27 in the 90, 30, and 200 nm ZnO microcosms, respectively. After 46 days' exposure of leaf litter, the highest decomposition rate was found in the control microcosms (0.47 m−1), followed by the 200 nm ZnO microcosms (0.37 m−1), the ZnSO4 microcosms (0.36 m−1), the 30 nm ZnO microcosms (0.28 m−1), and 90 nm ZnO microcosms (0.25 m−1), respectively. A significant decrease of the microbial biomass and enzyme activities (acid phosphatase, cellobiohydrolase, N-acetylglucosaminidase, polyphenol oxidase, and peroxidase) was observed in the ZnO NP exposure microcosms. ZnO NPs caused damage to the mycelium of aquatic hyphomycete and altered the composition of the fungal community associated with litter decomposition. In conclusion, the study expanded our understanding of ZnO NP toxicity on decomposition systems in freshwater ecosystems and highlighted the importance of using litter decomposition processes in NPs ecotoxicity assessments.

•Influent C/N ratio performed significant effect on NOB in CANON process.•NOB was suppressed by the organic addition when C/N was lower than 1.0.•NOB was enhanced by the organic addition when C/N was higher than 1.0.•Nitrobacter biodiversity was always higher than Nitrospira under different C/N ratio.•The influent C/N should be controlled around 1.0 for stable CANON process.The bioactivity and biodiversity of nitrite-oxidizing bacteria (NOB) in completely autotrophic nitrogen removal over nitrite (CANON) process should be suppressed to ensure stable operation. In this study, five membrane bioreactors (MBR) were operated as CANON process with different COD concentration, to investigate the influence on NOB structure. The five MBRs were seeded with same sludge and operated under totally same condition, while the influent C/N ratio was set as 0, 0.5, 1.0, 2.0 and 4.0, respectively. Results revealed that the low COD addition performed effective inhibition on NOB, the bioactivity and biodiversity of Nitrobacter and Nitrospira both decreased with the COD increasing when C/N ratio was lower than 1.0. However, massive COD addition (C/N ratio higher than 1.0) resulted in nitrite accumulation in CANON reactors, which then enhanced the NOB. It was concluded that the influent C/N ratio should be controlled around 1.0, to suppress NOB and ensure the stability.

•Novel nanocomposites of Cu2O, 3D-rGO, and nano-chitosan prepared via a feasible one-step in situ reduction synthesis.•High porosity and good electrochemical performance of Cu2O@3D-rGO@NCS.•High adsorption capacity and photocatalytic performance toward rhodamine B dye under simulated sunlight illumination.We reported a novel nanocomposite of cuprous oxide nanospheres, three-dimensional reduced graphene oxide, and nano-chitosan (Cu2O@3D-rGO@NCS) with diverse functionalities by a feasible one-step in situ reduction synthesis. The photocatalytic ability of Cu2O@3D-rGO@NCS nanocomposite using the degradation of rhodamine B (RhB) under simulated sunlight irradiation was accessed. The superior photocatalytic ability of Cu2O@3D-rGO@NCS compared to the pristine Cu2O nanospheres and Cu2O@3D-rGO nanocomposite, was attributed to high porosity from 3D-rGO, an efficient charge transfer from Cu2O to rGO, and high adsorption ability of NCS. The photodegradation efficiency toward rhodamine B (RhB) under simulated sunlight illumination was increased by approximately 68.2% and 46.8% when Cu2O@3D-rGO@NCS nanocomposite was used compared with the pristine Cu2O and Cu2O@3D-rGO nanocomposite, respectively. The recyclability results also demonstrated the excellent stability and reliability of the Cu2O@3D-rGO@NCS nanocomposite. The present work provides new insights into the synthesis and characterization of Cu2O@3D-rGO@NCS nanocomposite and its wide application in the environment protection issues.A novel nanocomposite of cuprous oxide nanospheres, three-dimensional reduced graphene oxide, and nano-chitosan with diverse functionalities were prepared by a feasible one-step in situ reduction synthesis. The developed nanocomposites possess high porosity and good electrochemical performance. It exhibits higher adsorption capacity and photocatalytic performance toward rhodamine B (RhB) dye than the pristine Cu2O nanospheres and Cu2O@3D-rGO under simulated sunlight illumination.

A sensitive aptasensor based on a nanocomposite of hollow titanium dioxide nanoball, three-dimensional reduced graphene oxide, and polypyrrole (TiO2/3D-rGO/PPy) was developed for lysozyme detection. A lysozyme aptamer was easily immobilized onto the TiO2/3D-rGO/PPy nanocomposite matrix by assembling the aptamer onto graphene through simple π-stacking interactions and electrostatic interactions between PPy molecular chains and aptamer strands. In the presence of lysozyme, the aptamer on the adsorbent layer catches the target on the electrode interface, which generates a barrier for electrons and inhibits electron transfer, subsequently resulting in decreased electrochemically differential pulse voltammetric signals of a gold electrode modified with TiO2/3D-rGO/PPy. Using this strategy, a low limit of detection of 0.085 ng mL−1 (5.5 pM) for detecting lysozyme was observed within the detection range of 0.1–50 ng mL−1 (0.007–3.5 nM). The aptasensor also presents high specificity for lysozyme, which is unaffected by the coexistence of other proteins. Such an aptasensor opens a rapid, selective, and sensitive route to lysozyme detection. This finding indicates that the TiO2/3D-rGO/PPy nanocomposite could be used as an electrochemical biosensor for detecting proteins in the biomedical field.

Ethephon is a plant growth regulator and is often applied in the process of fruit growth. It could result in considerable inhibition of cholinesterase in blood plasma and erythrocytes and is very harmful to human beings on excessive consumption. Nanocomposites from polyaniline and stannic oxide (SnO2@PANI) were synthesized and developed as the electrode material for detecting ethephon. Herein, SnO2 nanoparticles were prepared by the method of liquid phase precipitation. Afterwards, the as-prepared SnO2 nanoparticles were mixed with the aniline polymerization system to form the SnO2@PANI nanocomposite. The basic chemical components of the fabricated sensor were characterized in detail using Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. It was demonstrated that the developed SnO2@PANI nanocomposite exhibits good electrochemical performance with relatively low charge-transfer resistance. Compared with the pristine SnO2 and PANI, ethephon preferred to adsorb onto the SnO2@PANI nanocomposite surface because of the synergic interaction between the two components of SnO2 and PANI. The electrochemical impedance spectra illustrated that the fabricated ethephon sensor had excellent sensitivity, with a detection limit of 4.76 pg mL−1 within the range from 0.01 to 5 ng mL−1. Moreover, the developed electrochemical biosensor exhibits good selectivity and stability. All of these good performances provide a promising tool to detect illegal food additives.

A novel synthetic procedure is described for the fabrication of macroporous titanium dioxide (TiO2) films with an ordered, uniform pore framework comprised of nanocrystalline anatase mainly. The synthetic approach involved several processes. First, polymethyl methacrylate (PMMA) microspheres (87 nm) were synthesized by using a dispersion polymerization technique in the presence of Fenton reagent (FeSO4/H2O2) as a novel initiator, which has advantages such as simple and fast polymerization process without deoxygenation. Next, the templates of PMMA microspheres were assembled on clean substrates by dip-drawing technique. Finally, the macroporous TiO2 films with the average size of pores about 87 nm were obtained by sol-dipping template method and calcination to remove the templates at 550 °C. The test results of X-ray diffraction indicate that the nanocrystalline of anatase formed after calcination. The mechanisms of PMMA polymerization and template formation were proposed. Furthermore, both structures and morphologies of the composite films were investigated with field emission scanning electron microscope, and the processes of the thermal decomposition of PMMA and TiO2 gel were also discussed with thermo gravimetric analysis. This ordered and uniform pore framework could be used as the promising ultrafilter membranes showing active photocatalysis without intensive fouling.Graphical abstractHighlights► We report a novel fabrication of ordered, macroporous TiO2 films with pore size about 87 nm. ► We propose a facile synthesis of monodisperse PMMA microspheres used to assemble templates. ► Mechanisms of PMMA polymerization and template formation were discussed based on FT-IR, XRD, FESEM, and TG/DTG. ► The ordered and uniform pore framework we prepared could be used as photocatalysis TiO2 membranes to reduce fouling.

The combined method of demulsification and reverse osmosis (RO) has been employed in the present study to deal with the filature wastewater which is a sort of high-strength and stable oil/water emulsion produced in Shen Ma Industrial Co. Ltd. of China. The influence of varying the conditions for removal of oil, such as the dosage of demulsifier (a kind of cationic surfactant synthesized by authors), the pH of aqueous solution, heating temperature and time on demulsification have been investigated firstly. RO treatment using SE membranes (99.0% of average desalination rate for 2 g/L NaCl) of OSMONICS Co. was then conducted as the next polishing step to further lower both chemical oxygen demand (COD) and oil concentration in order to improve the water quality of permeate. The pilot-scale experiments results show that the removal rate of COD, turbidity and oil from the filature o/w emulsion can be obtained to 99.96%, 100% and 100%, respectively, in 30–50 min at 80–90 °C with demulsifier dosage of 0.1% (w/v) for demulsification, and at 35–40 °C with a driving press of 3.6 MPa and the flow rate of 1.5–1.6 m3/h for RO treatment. It was found that the water quality of permeate from the combined treatment process has been consistently excellent to meet the 1st grade discharge standard set in the Chinese National Standards for Integrated Wastewater (GB 8978-1996) due to both high removal rate of oil by demulsification and high COD rejection by RO.

•DLLME-UPLC-MS/MS was developed for the determination of OPEs from wines.•Results showed that high analytes recoveries were achieved with the proposed method.•The tested OPEs were found in the real samples with different levels.•It is promising to be used for the analysis of trace amount of OPEs in the future.In this study, dispersive liquid-liquid microextraction coupled with ultra-high-performance liquid chromatography–tandem mass spectrometry was developed for the analysis of five representative organophosphate esters (OPEs) in wine samples. Under optimized conditions, the proposed method resulted in good linearity (R2 > 0.9933) over the range of 0.1–100 μg L−1, with limits of detection (LODs, S/N = 3) and quantification (LOQs, S/N = 10) in the ranges of 0.48–18.8 ng L−1 and 1.58–62.5 ng L−1, respectively. Inter- and intra-assay precisions of RSD% ranged from 3.21% to 6.13% and from 1.69% to 7.63%, respectively. The spiked recoveries of target OPEs from white wine, red wine, and beer samples were in the ranges of 80–122%, 76–120%, and 76–110%, respectively, at two different concentration levels. The total concentrations of five OPEs found in white wine, red wine, and beer samples were in the ranges of 0.29–0.85 μg L−1, 1.00–3.05 μg L−1, and 0.86–1.47 μg L−1, respectively.

A sensitive aptasensor based on a nanocomposite of hollow titanium dioxide nanoball, three-dimensional reduced graphene oxide, and polypyrrole (TiO2/3D-rGO/PPy) was developed for lysozyme detection. A lysozyme aptamer was easily immobilized onto the TiO2/3D-rGO/PPy nanocomposite matrix by assembling the aptamer onto graphene through simple π-stacking interactions and electrostatic interactions between PPy molecular chains and aptamer strands. In the presence of lysozyme, the aptamer on the adsorbent layer catches the target on the electrode interface, which generates a barrier for electrons and inhibits electron transfer, subsequently resulting in decreased electrochemically differential pulse voltammetric signals of a gold electrode modified with TiO2/3D-rGO/PPy. Using this strategy, a low limit of detection of 0.085 ng mL−1 (5.5 pM) for detecting lysozyme was observed within the detection range of 0.1–50 ng mL−1 (0.007–3.5 nM). The aptasensor also presents high specificity for lysozyme, which is unaffected by the coexistence of other proteins. Such an aptasensor opens a rapid, selective, and sensitive route to lysozyme detection. This finding indicates that the TiO2/3D-rGO/PPy nanocomposite could be used as an electrochemical biosensor for detecting proteins in the biomedical field.