To develop an ultraefficient and reusable heterogeneous Fenton-like catalyst at a wide working pH range is a great challenge for its application in practical water treatment. We report an oxygen vacancy promoted heterogeneous Fenton-like reaction mechanism and an unprecedented ofloxacin (OFX) degradation efficiency of Cu doped Fe3O4@FeOOH magnetic nanocomposite. Without the aid of external energy, OFX was always completely removed within 30 min at pH 3.2–9.0. Compared with Fe3O4@FeOOH, the pseudo-first-order reaction constant was enhanced by 10 times due to Cu substitution (9.04/h vs 0.94/h). Based on the X-ray photoelectron spectroscopy (XPS), Raman analysis, and the investigation of H2O2 decomposition, •OH generation, pH effect on OFX removal and H2O2 utilization efficiency, the new formed oxygen vacancy from in situ Fe substitution by Cu rather than promoted Fe3+/Fe2+ cycle was responsible for the ultraefficiency of Cu doped Fe3O4@FeOOH at neutral and even alkaline pHs. Moreover, the catalyst had an excellent long-term stability and could be easily recovered by magnetic separation, which would not cause secondary pollution to treated water.

In this study, polyethylenimine-functionalized corn bract (PEI–CB) was first used to remove aqueous Cr(VI) via the “waste control by waste” concept. The results indicated that PEI–CB had an excellent performance for Cr(VI) removal and the maximum removal capacity was 438 mg/g. The adsorption of Cr(VI) was fitted to the Langmuir model, and kinetics of uptake could be described by a pseudo-second-order rate model well. Amine was proven to be the active center for Cr(VI) adsorption and partial reduction to Cr(III), while removal efficiency was enhanced at a lower pH value and higher temperature. Besides, nanosized Cr2O3 with a high purity was obtained by simple calcination of a Cr(VI)-laden adsorbent. Hence, this study provided a novel strategy for Cr(VI) wastewater remediation and pure Cr2O3 recovery. Prepared PEI–CB was then a promising alternative of low cost for replacement of the current expensive absorbent of removing Cr(VI) from wastewater from the view of sustainability.Keywords: corn bract; Cr(VI) removal; modification; polyethylenimine; recovery;

•Selenite is an inorganic pollutant in groundwater, affecting human health.•cLDHs with increased porosity and mesoporous structure, exhibit the excellent selenite removal performance.•High affinity and adsorption capacity of cLDHs were performed, and the maximum adsorption capacity of selenite was 179.59 mg/g.•Pseudo-second-order and Langmuir models well described kinetic and isotherm data.•The adsorbent could be used circularly 4 times efficiently.•Final removal of selenite ions is by reassembling and reconstructing to hydrotalcites structures.In this study, MgAl2O4 (cLDHs) with a typical spinel structure was synthesized by calcination of Mg/Al layered double hydroxides (LDHs) and was used as adsorbent for selenite (IV) removal from contaminated groundwater. Based on XRD, SEM/TEM and XPS analysis, the layered structure of LDHs was completely destroyed after calcination and pure bimetal oxides with flakiness structure was obtained. Compared with Mg/Al LDHs (66.89 mg/g), MgAl2O4 (cLDHs) exhibited an excellent selenite removal performance and the maximum adsorption capacity of selenite was 179.59 mg/g. The results indicated that Freundlich isotherm model is suitable to describe the adsorption equilibrium of selenite by cLDHs and the selenite adsorption also followed pseudo-second-order kinetics. Moreover, the influence solution pH and co-existed anion on the selenite by cLDHs was also investigated in detail. According all the experimental results, the removal mechanism of selenite was further discussed. Besides the surface adsorption and ion exchange by LDHs, most of selenite were removed by the intercalation into the interlayer region during the reconstruction process.

Two-dimensional (2D) materials have attracted great attention by researchers due to their fascinating properties and promising applications. However, the synthesis methods for few layers are usually difficult to expand to large area applications because of their low yield. In this paper, graphene-like MoSe2 nanosheets are successfully and scaleable synthesized by a facile and low-cost hydrothermal method under the synergy of PVP and graphene. The ultrathin MoSe2 nanosheets are typically 1–3 layers, which are confirmed by HRTEM. This unique structure makes this MoSe2 electrode material show superior activity toward the electrocatalytic hydrogen production with a low Tafel slope about 70 mV·dec–1. Furthermore, the synthesized graphene-like MoSe2 nanosheets had a high stability during the electrocatalytic process and we nearly cannot find the degradation after 1000 cyclic voltammetric sweeps.

The effects of food to microorganism (F/M) ratio and alcohol ethoxylate (AE) dosage on the methane production potential were investigated in treatment of low-strength wastewater by a submerged anaerobic membrane bioreactor (SAnMBR). The fate of AE and its acute and/or chronic impact on the anaerobic microbes were also analyzed. The results indicated that AE had an inhibitory effect to methane production potential (lag-time depends on the AE dosage) and the negative effect attenuated subsequently and methane production could recover at F/M ratio of 0.088–0.357. VFA measurement proved that AE was degraded into small molecular organic acids and then converted into methane at lower F/M ratio (F/M<0.158). After long-term acclimation, anaerobic microbe could cope with the stress of AE by producing more EPS (extracellular polymeric substances) and SMP (soluble microbial products) due to its self-protection behavior and then enhance its tolerance ability. However, the methane production potential was considerably decreased when AE was present in wastewater at a higher F/M ratio of 1.054. Higher AE amount and F/M ratio may destroy the cell structure of microbe, which lead to the decrease of methane production activity of sludge and methane production potential.

•A novel copper ions ratiometric fluorescence sensor was fabricated by integrating rhodamine fluorophore (RL) and CdTe@SiO2 QDs.•A simple device test strip for rapid and on-site detection of Cu2+ has been designed.•The sensor has an excellent sensitivity and the LOD is 8.4 nM.A novel ratiometric fluorescence sensor for rapid and on-site visual detection of Cu2+ was designed and synthesized by integrating yellow-emission rhodamine fluorophore (RL) and red-emission CdTe@SiO2 QDs. The as-prepared nanohybrid fluorescence sensor shows dual-emissions at 537 nm and 654 nm under a single excitation at 500 nm in the presence of Cu2+. Owing to the strong chelating ability of RL toward Cu2+, the yellow fluorescence of RL could be selectively enhanced while the red fluorescence of CdTe QDs is almost unchanged, leading to an obvious fluorescence color change from red to yellow, which could be used for visual and ratiometric detection of Cu2+. This nanohybrid sensor exhibits excellent selectivity, sensitivity and anti-interference to Cu2+ detection and the detection limit is as low as 8.4 nM. Additionally, a simple device test strip for rapid and on-site detection of Cu2+ has been designed by immobilizing the RL-CdTe@SiO2 QDs on a common filter paper. This simple and effective paper-based sensor has a visual detection limit of 0.5 μM, showing its promising application for on-site and rapid sensing of Cu2+ in pollution water.Download high-res image (118KB)Download full-size image

•A novel hybrid ratiometric fluorescent nanosensor has been developed.•The nanosensor can detect Cu2+ sensitively due to ion promoted oxidation mechanism.•The detection limit of the nanosensor towards Cu2+ is 41.71 nM.•The nanosensor shows high performance for Cu2+ detection in actual water samples.Copper is a highly toxic environmental pollutant in the environmental, biological and chemical fields. Therefore, sensitive, selective and visual detection of Cu2+ is very important for human health and practical applications. Herein, a novel hybrid ratiometric fluorescent nanosensor was developed for rapid and on-site visualization of Cu2+ on the basis of integrating benzothiazole fluorophore (MDBT) and red-emissive quantum dots (QDs) embedded in silica nanospheres. Such hybrid ratiometric fluorescent nanosensor exhibits dual emissions at 420 and 640 nm under a single excitation wavelength. Due to the ions promoted oxidation reaction of Cu2+ towards MDBT, the fluorescence of MDBT can be selectively enhanced. Although the embedded QDs are insensitive to the analyte, variations of the dual emission intensity ratios display continuous colour changes from red to blue. The ratiometric fluorescent approach shows high sensitivity and selectivity towards Cu2+ against other interfering metal ions. The detection limit of Cu2+ for the hybrid ratiometric fluorescent nanosensor is determined to be 41.71 nM, which is much lower than the allowable level of Cu2+ (∼20 μM) in drinking water set by U.S. Environmental Protection Agency. Furthermore, this kind of novel nanosensor can also be applied for Cu2+ detection in actual water samples and exhibits excellent detection ability. This hybrid ratiometric fluorescent nanosensor is simple, fully self-contained and thus potentially attractive for visual identification without the need of elaborate equipments.A novel hybrid ratiometric fluorescent nanosensor was developed for rapid and on-site visualization of Cu2+ based on the ions promoted catalytic oxidation mechanism.Download high-res image (96KB)Download full-size image

•The CH3NH3PbBr3 perovskite quantum dots (QDs) emitted intense green fluorescence with high quantum yield of 50.28%.•The perovskite QDs were applied for ultratrace mercury ions (Hg2+) detection with detection limit of 0.124 nM (24.87 ppt).•The fluorescence of perovskite QDs can only be quenched by Hg2+ which exhibits high selectivity.•A spot plate test for visual detection of Hg2+ in solution has been explored.Mercury ions sensing is an important issue for human health and environmental safety. A novel fluorescence nanosensor was designed for rapid visual detection of ultratrace mercury ions (Hg2+) by using CH3NH3PbBr3 perovskite quantum dots (QDs) based on the surface ion-exchange mechanism. The synthesized CH3NH3PbBr3 QDs can emitt intense green fluorescence with high quantum yield of 50.28%, and can be applied for Hg2+ sensing with the detection limit of 0.124 nM (24.87 ppt) in the range of 0 nM–100 nM. Furthermore, the interfering metal ions have no any influence on the fluorescence intensity of QDs, showing the perovskite QDs possess the high selectivity and sensitivity for Hg2+ detection. The sensing mechanism of perovskite QDs for Hg2+ is has also been investigated by XPS, EDX studies, showing Pb2+ on the surface of perovskite QDs has been partially replaced by Hg2+. Spot plate test shows that the perovskite QDs can also be used for visual detection of Hg2+. Our research indicated the perovskite QDs are promising candidates for the visual fluorescence detection of environmental micropollutants.Perovskite quantum dots were applied for ultratrace Hg2+ detection based on surface ions exchange mechanism.Download high-res image (412KB)Download full-size image

A novel aggregation-induced emission (AIE) active molecule, compound 1, was synthesized for the first time. Simultaneously, an ultra-sensitive and selective chemosensor 2 for the “turn-on” sensing of As3+ based on the AIE mechanism has been developed by combining cysteine with compound 1.

This study proposed a new and previously unconsidered reaction mechanism in the activation of peroxymonosulfate. We report that singlet oxygen (1O2) rather than ˙OH or SO4˙− was the dominant reactive oxygen species towards the efficient degradation of ofloxacin and phenol, demonstrating a promising application in real wastewater treatment.

Phosphorescent 4-morpholineethanesulfonic acid-capped Mn-doped ZnS (MES-MnZnS) quantum dots were developed for sensitively and selectively detecting L-tyrosine (L-Tyr) in human urine. L-Tyr can effectively quench the phosphorescence of MES-MnZnS even at low concentration levels. The mechanism of phosphorescence quenching is ascribed to electron transfer from MES-MnZnS QDs to L-Tyr. Under optimal conditions, the phosphorescent probe allowed a highly sensitive detection of L-Tyr with a wide linear range of 0.5–100 μM and a low detection limit of 0.22 μM. The developed method offers good selectivity over other compounds and was applied to determine L-Tyr in real urine samples with quantitative spike recoveries from 96.7% to 106.2%.

Phosphorescent 4-morpholineethanesulfonic acid-capped Mn-doped ZnS (MES-MnZnS) quantum dots were developed for sensitively and selectively detecting L-tyrosine (L-Tyr) in human urine. L-Tyr can effectively quench the phosphorescence of MES-MnZnS even at low concentration levels. The mechanism of phosphorescence quenching is ascribed to electron transfer from MES-MnZnS QDs to L-Tyr. Under optimal conditions, the phosphorescent probe allowed a highly sensitive detection of L-Tyr with a wide linear range of 0.5–100 μM and a low detection limit of 0.22 μM. The developed method offers good selectivity over other compounds and was applied to determine L-Tyr in real urine samples with quantitative spike recoveries from 96.7% to 106.2%.

•Effect of water characteristics on bioenergy recovery in sewage by AnMBR was studied.•Recovery efficiency was inhibited by 15.6% if suspended solid was present in sewage.•Anionic surfactant caused a decreased efficiency by 26% due to toxicity to microbe.•55.7% of decreased energy recovery at 10 °C was due to lower growth rate of microbe.Effect of wastewater characteristics on bioenergy recovery in sewage treatment by anaerobic membrane bioreactor (AnMBR) was investigated. Based on COD removal, sludge concentration change and COD mass balance, nonionic surfactant or operation at 20–25 °C had no effect on the energy recovery with COD conversion of 72–79%. The anaerobic microbes can cope with the characteristic by releasing more SMP/EPS or changing its community structure. Compared with Control (6.99 × 107 kJ/d, HRT 12 h), with suspended solid or operation at 15 °C and 10 °C, the captured energy was only 5.90 × 107 kJ/d, 6.0 × 107 kJ/d and 3.10 × 107 kJ/d, respectively while the energy in dissolved methane was 1.08 × 107 kJ/d, 0.98 × 107 kJ/d and 1.26 × 107 kJ/d. Hence, the recovery efficiency was decreased by 15.6%, 14.2% and 55.7%. The recovery also decreased by 26% (5.17 × 107 kJ/d) in the presence of anionic surfactant. The toxicity of anionic surfactant to the anaerobic microbes and lower growth rate of microorganism at psychrophilic temperatures were responsible to the decrease of bioenergy recovery efficiency. SS accumulation will finally increase the loading rate of sludge and decrease the bioenergy recovery from the long-term view.

•LAS caused a lower sewage treatment efficiency but a higher membrane fouling rate.•Biogas production rate decreased by 26%: 2.11 L/d with LAS vs. 2.55 L/d in control.•LAS was removed by adsorption rather than degradation with an efficiency of 30–70%.•LAS adsorption had a more negative effect on methanogen than acidification microbe.•SAnMBR is not suitable to treat LAS containing sewage with higher concentration.The effect of linear alkylbenzene sulfonate (LAS), a typical anionic surfactant, on the sewage treatment by a submerged anaerobic membrane bioreactor (SAnMBR) was investigated by a 243 days operation. The changes of treatment efficiency, methane recovery and sludge activity due to the presence of LAS in sewage was studied in detail. Compared with control (96.8% and 2.87 L/d), lower COD removal (95.2%) and biogas production rate (2.11 L/d) were found at a LAS dosage of 5 mg/L. Besides, LAS was removed by adsorption rather than degradation on the sludge (30–70%). Its adsorption can lead to significant loads in sewage sludge, which then decrease the methane production activity. The recovery efficiency of potential bioenergy was decreased by 20% and 26% at LAS of 2.5 mg/L and 5.0 mg/L, respectively. The results indicated that LAS had a more negative effect on the acetoclastic methanogens than acidogenic microbiota and the LAS inhibition to methanogen activity was responsible for the decrease of SAnMBR performance. Moreover, LAS caused a higher membrane fouling rate than the control experiment due to the microbial self-protection behavior in coping with the LAS in sewage. SAnMBR was hence not suitable to dispose LAS containing sewage with higher concentration.Download high-res image (118KB)Download full-size image

Fabricating a cost effective hydrogen evolution reaction catalyst without using precious metal elements is in crucial demand for environmentally-benign energy production. In this work, the thin and edge-rich molybdenum disulfide nanosheets, with carbon doped in the interlayers and decorated on graphene, were developed by a facile solvothermal process. The as-synthesized nanohybrids exhibited high catalytic ability for the hydrogen evolution electrochemical reaction with an onset overpotential of 0.165 mV and a Tafel slope of 46 mV dec−1. Furthermore, the prepared nanohybrids also showed better durability and stability. Our work may lead to a potential method for in situ production of metal carbide–sulphur hybrid nanomaterials with promising applications for the hydrogen evolution reaction.

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

•Hollow zeolite spheres were synthesized by one-step organic-free hydrothermal method from natural minerals.•The diameters of the microsphere were controlled with potassium cation concentration.•A possible K-induced Ostwald ripening reversed crystal growth process was proposed.A novelty hierarchical hollow nitrate cancrinite zeolite microspheres (HNCMs) with micro-plate crystals act as sphere shell and wrapped with large number of nanorods crystal in the center of the microspheres were synthesized by a simple organic-free hydrothermal synthesis methods. With the adjustment of potassium cation concentration in synthetic system, nitrate cancrinite zeolites realize morphology tunable architectures from nanorod to HNCMs. A systematic investigation of the crystal growth over different crystallization stages indicates a stepwise crystallization progress of HNCMs. First, the primitive nitrate cancrinite nanoplatelets self assembled to yield solid spherical clusters. Then the spherical clusters undergo a surface to core crystallization progress which was supposed to be the reason for the formation of hollow cores. This work provides an alternative strategy for the synthesis of spherical hollow zeolite materials with tunable architectures, which may potentially be used in the field of separation, catalysis and biomedicine.

•The 3D graphene aerogel was prepared via an innovative method.•Pd nanoparticles decorated on graphene aerogel were synthesized and characterized.•Pd/graphene aerogel catalyze ammonia borane complex to release hydrogen efficiently.•Metal-support interaction mode between Pd NPs and graphene aerogel was investigated.In this work, a novel three dimensional (3D) Pd/graphene aerogel hybrid was successfully synthesized and characterized. The preparation process of the Pd/graphene aerogel was also discussed systematically. Experimental results indicated that this kind of 3D Pd/graphene aerogel hybrid exhibited excellent catalytic activity on the ammonia borane hydrolysis to release hydrogen with the turnover frequency value of 9.70 molH2molmetal−1min−1molH2molmetal−1min−1, and activation energy Ea value of 30.82 kJ/mol, which is higher than that of 2D Pd/RGO and original Pd nanoparticles. Furthermore, the abundant defects of graphene aerogel support can transfer the electrons of Pd nanoparticles to graphene aerogel due to the metal-support interaction, which is beneficial to the ammonia borane hydrolysis reaction. In addition, the pore-rich 3D Pd/graphene aerogel has offered huge effective reacting acreages for ammonia borane hydrolysis, which is helpful for its reusability.

•Hierarchical BiOCl microspheres were synthesized by a facile hydrothermal process.•BiOCl microspheres possess the high photocatalytic activity under visible light.•BiOCl microspheres possessed the very high and stable photocatalytic activity.•The mechanism for photocatalytic degradation by BiOCl microspheres was studied.In this paper, the hierarchical BiOCl microspheres were successfully synthesized by a facile hydrothermal process. And the morphology, composition, crystal growth, and energy band-gap of hierarchical BiOCl microspheres were characterized systematically. The hierarchical BiOCl microspheres possess a narrow band gap of 2.25 eV. Besides, their photocatalytic activity under visible light irradiation was investigated, and found the microspheres possessed the very high and stable photocatalytic activity. Furthermore, the mechanism for photocatalytic degradation of organic molecules by hierarchical BiOCl microspheres was detailed studied.The hierarchical BiOCl microspheres possess the narrow energy band gap of 2.25 eV. And they possessed the very high and stable photocatalytic activity which attributed to the photoelectrons on the surface interacted with the absorbed O2 molecules to generate highly active O2− species.

Large magnetoresistance (MR) effects in bismuth depend on crystallinity and grain size. In this paper, we report for the first time Bi micron particles (BMPs) with large MR that can be produced on a large scale and with high quality through a simple low-temperature solvothermal reduction route in a highly alkaline media system. Almost all the BMPs have the very interesting structural characteristic of a rounded truncated octahedral shape. In addition, the reaction and growth mechanism of the truncated octahedral BMPs is proposed on the basis of experimental data. It starts with an alkaline media-homogeneous nucleation, and then small crystal nuclei aggregate into irregular nanoflakes and assemble into polycrystalline microspheres at the lead of the CTAC soft template with the nucleus growing at the same time. Then surface recrystallizations happen to form the truncated octahedral bismuth micron particles via Ostwald ripening. With prolonged time, recrystallization continues from the surface to the core anisotropically. Moreover, the MR of the truncated octahedral BMPs can reach up to 130% at room temperature (T = 300 K) and 700% at temperature T = 10 K in an 8 T field, respectively, with nonhysteretic and quasi-linear field dependence.

One-dimensional (1D) single-crystalline trigonal selenium nanorods (t-Se NRs) were prepared through a “solid–solution–solid” method by dispersing the prepared amorphous α-Se spheres in ethanol. The single crystal structure of the t-Se NRs could be excited under visible light, with a band gap of 1.56 eV. The t-Se NRs were found for the first time to display noticeable photocatalytic activity under visible light. In addition, the rate of photodegradation of methyl orange (MO) in the visible–Se NRs–H2O2 system (1.7 × 10−1 min−1) is about 17 times greater than that in the visible–Se NRs–HCl system with equal pH (1.0 × 10−2 min−1). Furthermore, we proposed a photocatalysis mechanism of the visible–Se NRs–H2O2 system based on electron paramagnetic resonance (EPR) characterization and studying the effect of different reactive species.

A novel nanostructure composed of magnetic iron oxide nanocrystals (MI) anchored on a sepiolite nanofiber backbone with excellent arsenic adsorption performance has been successfully developed. Sepiolites (SEPs) as typical nano-geomaterials with low cost, large specific surface (ca. 300 m2 g−1) and tunable surface chemistry are chosen as the host matrix. Transmission electron microscopy confirms that uniform Fe2O3 nanocrystals with an average particle size of ∼9 nm are spatially well-dispersed and anchored on the sepiolite backbone at a high Fe2O3 content of 33.2 wt%, rather than forming aggregates on the external surface. MI/SEPs have a high specific surface area, high loading amount, the non-aggregated nature of Fe2O3 nanocrystals, good dispersion and magnetic properties, making them promising for use as a separable adsorbent for As(III) removal with high adsorption capacity and magnetic separation properties. The maximum adsorption capacity has a wonderful value of 50.35 mg g−1 for As(III) on the MI/SEPs, which is higher than those of previously reported adsorbents. Moreover, MI/SEPs can reduce the concentration of As(III) from 140 to 1.5 μg L−1. MI/SEPs also show high removal ratios of 96.4% without any pre-treatment in real groundwater with an arsenic concentration of 456.5 μg L−1.

•Monodisperse PdxSn100−x NPs with controlled compositions were synthesized.•PdxSn100−x NPs catalyze ammonia borane hydrolysis to release hydrogen effectively.•The catalytic hydrolysis ability of PdxSn100−x NPs is highly composition dependent.•Pd69Sn31 NPs are the most active catalysts on ammonia borane hydrolysis.Composition controllable monodisperse palladium tin nanoparticles (PdxSn100−x NPs, x = 77, 69, 63, 52, 49) were prepared by the thermal reduction of palladium bromide and tin acetate in the presence of trioctylphosphine and oleylamine. The NPs were investigated for their catalytic abilities of hydrogen generation from hydrolysis of ammonia borane complex. Deposited on a carbon support without any further treatment, these NPs were active nanocatalysts for hydrolysis of ammonia borane complex, and their catalytic activities were highly composition dependent. Among these NPs studied, Pd69Sn31 NPs exhibited the highest catalytic activity and stability under mild reaction conditions. Kinetic investigations showed that the catalytic hydrolysis of ammonia borane was first-order with respect to catalyst concentration and zero-order with respect to ammonia borane concentration. The activation energy for the hydrolysis of ammonia borane complex in the presence of Pd69Sn31 NPs was calculated to be 27.22 kJ mol−1. The PdxSn100−x NPs are promising candidates toward the practical development of the ammonia borane complex as a feasible hydrogen storage medium for fuel cell applications under ambient conditions.PdxSn100−x NPs with are efficient catalysts on ammonia borane hydrolysis reaction to release hydrogen with their catalytic ability being highly composition dependent, and Pd69Sn31 NPs are most efficient catalyst with the high stability and recyclability under ambient conditions.

We have developed a novel one-pot synthetic procedure for monodisperse palladium tin bimetallic alloy nanoparticles (NPs) with tunable compositions and sizes by the co-reduction of tin(II) acetate and palladium(II) bromide in the presence of oleylamine and trioctylphosphine. These NPs loaded on active carbon (PdSn/C) were used as active catalysts for Heck reactions, and exhibited composition dependent catalytic activities. Among these nanocatalysts, Pd63Sn37 NPs showed the best catalytic performance which is even superior to pure Pd NPs.

Amine-functionalized ordered mesoporous alumina (NH2-OMA) was synthesized through a facile and reproducible method. Its organic dyes adsorption characteristics, including adsorption isotherms, adsorption kinetics, the stability and reusability of the adsorbents were investigated. This material exhibited strong affinity to methylene blue and extremely high adsorption capacity. The maximum adsorption capacity value reached 657.89 mg g−1. Adsorption kinetics was best described by the pseudo-second-order model. Equilibrium data were well fitted to the Langmuir isotherm model.

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

The crystalline mesoporous MgO–ZrO2 solid solutions have been fabricated by a simple evaporation induced self assembly procedure with zirconyl chloride octahydrate (ZrOCl2·8H2O) and magnesium nitrate tetrahydrate (Mg(NO3)2·4H2O) as metal precursors and triblock co-polymer of Pluronic P123 as templating agent. Small-angle X-ray diffraction (SXRD) and transmission electron microscopy (TEM) results showed that ordered mesoporous structure and worm-like mesoporous structure were obtained under different calcine temperatures. Wide angle X-ray diffraction (WXRD) indicated that the formation of homogeneous solid solutions were responsible for the stable tetragonal phase. All MgO–ZrO2 solid solutions were endowed with strong basicity (H_ = 9.3–12.2) and high water resistance. The Mg2+ doped into zirconia lattice could stabilize the tetragonal phase and prevent zirconia crystals from excessive growth. This kind of structure could also inhibit basic sites dissolve in water in the reaction and effectively improve the thermal stability of products.Graphical abstractHighly ordered crystalline mesoporous MgO–ZrO2 solid solutions have been fabricated by a simple evaporation induced self assembly procedure when the molar ratio of Mg/Zr was 0.25–1.0. The formation of solid solution stabilizes the tetragonal phase and effectively prevents the basic components from leaching in the reaction media involving water..Highlights► We synthesized ordered mesoporous MgO–ZrO2 solid solution with a simple method. ► The crystalline wall of MgO–ZrO2 can efficiently improve the thermal stability. ► This kind of structure could inhibit basic sites dissolve in water in the reaction. ► The new MgO–ZrO2 solid solution shows very promising applications in fine chemistry.

Among many kinds of noble metal catalysts, platinum is the most efficient and widely used as automotive exhaust catalysts for treatment to remove poison gases. Due to the regular pore system and controllable pore size, mesoporous silica has been acknowledged as supports of adsorption, separation, catalysts for the extremely large surface areas and shape selective properties. SBA-15 supported Pt particles are prepared by a facile method and characterized by X-ray diffraction, Transmission Electron Microscopy and N2 isotherms techniques. Results indicate that the Pt precursor is introduced into the mesoporous successfully and all of the particles are confined in SBA-15 with monodispersed form and uniform size. The catalytic activity of Pt-SBA-15 on oxidation of carbon monoxide are also investigated and the result indicate that the catalysts possess high catalytic activity, catalytic efficiency and stability on oxidation of CO.

Mesoporous MnO2 with uniform nanorod morphology and mesoporous β-MnO2 were prepared using SBA-15 and KIT-6 as the templates, respectively. XRD, nitrogen adsorption analysis, SEM, TEM and EDX techniques were used for the structural characterization. The electrochemical properties of the MnO2 samples were studied using alkaline Zn/MnO2 batteries in a 9 M KOH electrolyte solution. Compared to the commercial electrolytic manganese dioxide (EMD), the discharge capacity of the mesoporous MnO2 nanorods increased by 74.98%, 119.74% and 146.19% at constant currents of 50, 250 and 500 mA g−1, respectively, while the discharge capacity of the mesoporous β-MnO2 increased by 63.58%, 95.14% and 100.23%.

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

Ternary alloys of CdSxSe1−x nanorods have been synthesized by the thermal treatment of Cd2+ dispersed polyethylene glycol 2000 gel (PEG2000) with ethylenediamine solution of sulfur and selenium in a sealed system at 180 °C for 24 h, during which the proportion between S and Se in the nanorods was controlled by the ratios of every starting material to each other. The alloyed ternary CdSxSe1−x nanorods are highly crystalline without any other phase. The optical property these nanorods could be manipulated by modulating the composition of S and Se.

The spherical particles CdSexS1 − x with 30–80 nm in radius have been successfully prepared by the hydrothermal reaction at 200 °C. The structure characterization which has been carried out using X-ray diffraction (XRD) shows hexagonal crystal structure. Novel properties have been observed via UV–visual absorption spectra and photoluminescence (PL) spectra. The absorption shoulder and the luminescence emission peaks have been tuned by changing the mole ratio of Se in the CdSexS1 − x samples.

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

Simple chemical deposition was used to prepare three types of amoxicillin nanostructures. Their morphology and size were characterized by scanning electron microscopy, and their chemical bonds were examined by Fourier transform infrared spectrum. Our results show that amoxicillin nanobelts, nanofibers, nanoparticles, and microparticles can be obtained by changing the pH in solutions of amoxicillin sodium. To some degree the controllable growth of amoxicillin can be realized.

Sonochemical method was used to prepare ultrafine Azithromycin. The morphology and size distribution of the particles prepared were characterized by scanning electron micrograph (SEM) and Zetasizer Nanoinstrument. The chemical bonding of production was examined by Fourier transform infra-red absorption spectroscopy (FT-IR). The result shows that different diameter particles of Azithromycin were prepared, and no fundamental bonding change in the Azithromycin molecule after preparation.

Three kinds of tetrapod-like ZnO nanostructures have been synthesized simultaneously via pure Zn chemical vapor deposition on silicon wafers with (111) orientation (Si (111)) at 920 °C. X-ray diffraction indicates that the nanotetrapods are of wurtzite structure. The morphology and the microstructure of the nanotetrapods are investigated by the scanning electron microscopy. Selected area electron diffraction shows the growth direction, and energy dispersive X-ray spectroscopy reveals the atomic composition ratio of Zn/O. The growth process is briefly discussed. The optical property of the products was also recorded by means of photoluminescence spectroscopy.

The sizes and morphologies of hexagonal phase ZnO crystals were successfully controlled by a hydrothermal process in the presence of poly (acrylic acid) (PAA). The dosage of NaOH in this reaction system proved to be crucial in the growth process. With the increase of dosage from 0.7 g to 3.0 g, the morphologies of the ZnO crystals changed from nanoplates to microrods. Their optical properties were also investigated.

Leaching studies of low-grade pyrolusite, containing 11.84% Mn with high silicon, were carried out using sodium sulfite as a reductant in ammonium sulfate medium. Various process parameters including temperature, leaching time, solid-liquid ratio, quantity of ammonium sulfate, as well as the amount of reducing agent were studied in detail. The manganese extraction yield was the response of the process. Temperature and reagent concentration exerted the most important positive effect on the manganese extraction. The optimized conditions showed that when the amount of reducing agent was a stoichonmetric amount, over 90% manganese extraction and the lowest impurities were achieved, the amount of heavy metal impurities in the manganese leaching liquid was less than 5 mg/L, and almost no iron and aluminum were extracted in 3 mom ammonium sulfate concentration at 100 °c in 45 min.

Alloyed ternary CdSxSe1-x nanorods have been synthesized by the thermal treatment of Cd2+-dispersed polyethylene glycol 2 000 gel (PEG 2000) with ethylenediamine solution of sulfur and selenium in a sealed system at 180 °C for 24 h, in which the ratio of S to Se in the nanorods was controlled by adjusting the relative amounts of the starting materials. Based on the results of experiments, it is found that the CdSxSe1-x nanorods were also synthesized with several sulfur sources by the method. X-ray diffraction (XRD) shows that the alloyed ternary CdSxSe1-x nanorods are highly crystalline, and no other phase was observed in these nanorods.

The nanometer MnO2 has outstanding electrochemical performance theoretically, but it is not suitable for actual utilization, which may result in capacity decrease and resource waste. In this study we have utilized the characterizations of the nanometer material, synthesized a type of nanometer α-MnO2 through KMnO4 and KNO3 with hydrothermal method, and mixed the products into micron electrolytic manganese dioxide (EMD) to enhance the electrochemical performance of the electrode. The cyclic voltammogram and galvanostatical discharge measurements of the samples were investigated. It is found that the 50% nanometer MnO2 mixed electrode has the best electrochemical performance. The electrochemical performance improvement mechanism of the sample nanometer MnO2 mixed into micron EMD was discussed. With the existence of electrolyte, the nanometer MnO2 particles filled into the interspaces of the micron EMD particles, the mass and charge transfer conditions of the electrode reaction were improved, and the electrode polarization was diminished.

•AE was all degraded and converted into CH4 by anaerobic microbes in SAnMBR.•Sludge acclimation to AE greatly changed the microbial community structure.•Tolerance ability of methanogenic activity to AE was greatly enhanced.•Higher concentration of AE caused an increase of membrane fouling rate.The effect of alcohol ethoxylates on the treatment of municipal wastewater by a submerged anaerobic membrane bioreactor was investigated by a 400 days operation including the treatment efficiency, methanogenic activity of sludge and microbial community structure. The results indicated that alcohol ethoxylates (5.0–200 mg/L) was efficiently degraded and converted into methane due to the similar COD removal 95.5–98.8% and rising biogas production rate (2.30–4.25 L/d) compared with control (96.8% and 2.55 L/d). The microbes in sludge could copy with the presence of alcohol ethoxylates in wastewater by releasing more SMP and EPS, which caused a higher membrane fouling rate. Moreover, via long term acclimation, the specific methanogenic activity of sludge was greatly enhanced due to the changes of microbial community structure. Hence, the sludge self-acclimation to alcohol ethoxylates was responsible to the efficient methane recovery in treatment of municipal wastewater.Download high-res image (200KB)Download full-size image

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

This study proposed a new and previously unconsidered reaction mechanism in the activation of peroxymonosulfate. We report that singlet oxygen (1O2) rather than ˙OH or SO4˙− was the dominant reactive oxygen species towards the efficient degradation of ofloxacin and phenol, demonstrating a promising application in real wastewater treatment.

A novel aggregation-induced emission (AIE) active molecule, compound 1, was synthesized for the first time. Simultaneously, an ultra-sensitive and selective chemosensor 2 for the “turn-on” sensing of As3+ based on the AIE mechanism has been developed by combining cysteine with compound 1.

The coexistence of arsenic and fluoride in groundwater has attracted extensive attention worldwide, and it is of crucial importance to efficiently remove them. In this study, hierarchically meso-/macroporous MgO using nanosheets as building blocks and with pore size distribution in the range of 10 to 150 nm was synthesized. The maximum adsorption capacities for As(III) and F were found to be about 540.9 mg g−1 (7.22 mmol g−1) and 290.67 mg g−1 (15.30 mmol g−1), respectively. Research indicated that a broad and multimodal pore size distribution provided suitable channels for ion diffusion, which were conducive to the proximity of contaminants to the internal surfaces of the adsorbent. Thermodynamic adsorption models demonstrated that two types of active sites coexisted on the MgO surface. The adsorption mechanisms of As(III) and F were proposed to include surface complexation as well as exchanges with hydroxyl and carbonate groups. Moreover, the removal rates of As(III) and F for a co-contaminated groundwater sample were determined to be 98.9% and 95%, respectively.