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In this work, simple chemical reduction method is used to prepare Pd–Sn nanocatalysts supported on carbon for ethanol electro-oxidation in alkaline environment using ethylene glycol as reductant. The composition, structure and morphologies of PdSn/f-C catalysts are investigated by X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray and transmission electron microscopy. The electro-chemical activity and durability of as-obtained PdSn/f-C nanocatalysts are investigated and determined by cyclic voltammetry and Chronoamperometric measurements. The obtained results demonstrate that as prepared PdSn/f-C nanocatalysts have uniform dispersion and small particle size. In addition to, the as prepared PdSn/f-C nanocatalysts have higher electro-chemical activity and better stability toward EOR in alkaline environment than those of Pd/f-C and commercial Pd/C (JM) nanocatalysts. Specifically, the electro-catalytic activity of Pd 1.5 Sn/f-C nanocatalyst (3413.3 mA mg Pd − 1 ) is almost 8.6 times higher than Pd/C (JM) nanocatalyst (355.2 mA mg Pd − 1 ), which has competitive power among reported Pd–Sn catalysts. These results indicate that the uniform carbon supported PdSn nanostructure are promising electrocatalysts for direct ethanol fuel cells. Image 1 • Bimetallic PdSn/f-C was successfully synthesized by chemical reduction method. • Pd 1.5 Sn/f-C catalyst displays the high activity and durability for alkaline EOR. • Sn is the key factor for enhancing electrocatalytic performance of EOR. [ABSTRACT FROM AUTHOR]

In this study, the sources of nine heavy metals (Cd, As, Hg, Cu, Pb, Ni, Cr, Zn, and Co) in the sediments of the Bohai Sea were quantitatively identified through a positive factor matrix to provide better advice for marine and coastal management. In Bohai Sea sediments, most metals fell below detectable contamination levels, including As, Cu, Pb, Ni, Cr, Zn, and Co. Unfortunately, Bohai Sea sediments were moderately to significantly enrich with Cd and Hg, posing potentially adverse ecological risks to aquatic ecosystems. Our modeled results showed three factors representing natural, anthropogenic, and atmospheric deposition sources. Enriched Cd and Hg were likely derived from anthropogenic activities through river runoff and atmospheric deposition due to adjacent Zn smelting and chlor-alkali production, respectively. The other metals were mainly derived from natural sources. • Nine heavy metals were analyzed in 404 surficial sediments from the Bohai Sea. • A positive factor matrix method was used to trace heavy metal sources of sediments. • Enriched Cd may be derived from anthropogenic activities via riverine discharge. • Hg is mostly likely enriched by atmospheric deposition. [ABSTRACT FROM AUTHOR]

Direct ethanol fuel cell can convert chemical energy into electric energy directly, and has the advantages of being free from Carnot cycle and being friendly to environment, so it has a broad application prospect. However, the insufficient activity and toxicity resistance of anodic catalysts limit their commercial application, mainly due to the limited adsorption sites and the toxic inactivation of catalysts resulting from the production of toxic intermediates (CO ads) during the ethanol oxidation reaction (EOR) process. In this study, the Au@PdAg porous hemispherical catalyst assembled by nanotubes was successfully prepared by soft template method and co-reduction method using dioctadecyl dimethyl ammonium chloride (DODAC) as surfactant, and its EOR performance was tested. Au@Pd 1.0 Ag 1.0 has the highest mass current density with a peak value of 4048.8 mA mg Pd − 1 , which is 7.8 times of Pd/C (JM). After 5000 s stability test, the residual current density value is still 863.4 mA mg Pd − 1 . The results showed that the introduction of the oxygenophilic metal Ag was conducive to the formation of OH ads and the oxidation of CO ads. The porous structure of the nanotube assembly facilitates electron transfer and provides more adsorption sites, which makes the catalyst show good electrocatalytic activity and anti-CO poisoning ability. [Display omitted] • Anisotropic hemispherical nanostructure was formed by BO 2 − inhomogeneous adsorption. • Porous hemispherical Au@PdAg catalyst enhancing ethanol electrooxidation was prepared. • The catalyst exhibited excellent activity and regenerative for ethanol oxidation. [ABSTRACT FROM AUTHOR]

This work reports the preparation of ternary hollow PdSnNi (H-PdSnNi) catalysts with nanochannels toward the electrooxidation of ethanol in alkaline medium, in which the Pd and Sn nanoparticles grow on the surface of H-Ni microspheres by galvanic replacement method. The reaction is driven by the difference in the equilibrium potential of the Pd/PdCl 4 2− , Sn/Sn 2+ and Ni/Ni 2+ redox couples. Structural measurements indicate the hollow structure of the H-PdSnNi nanocomposites and the well distribution of nanoparticles. The distinctive Pd NPs and Sn NPs loaded on H-Ni microspheres can efficient prevent Pd NPs from the aggregation and provide a high specific area. Electrochemical tests illustrate that the H-PdSnNi 2.5 catalyst has large electrochemically active surface area and prominent activity (1902 A g −1 ). After the same chronoamperometery test, the residual current density of H-PdSnNi 2.5 catalyst remains 1006 A g −1 which is 7.1 times that of Pd/C (JM) (140 A g −1 ). The superior activity and stability of the H-PdSnNi catalysts toward ethanol electrooxidation are attributed to the hollow structure, the electron effect and bifunctional mechanism due to the addition of Ni and Sn. This work will spur the study of the structure and composition (ternary-metallic) of electrocatalysts toward EOR with superior electrooxidation performance. [ABSTRACT FROM AUTHOR]

Background metal concentrations are important in assessing pollution level of marine sediments; however, they can be significantly altered by local depositional environments, resulting in significant errors in regional pollution assessment. This study was based on the investigation of the background levels of heavy metals in the Bohai Sea sediments using sediment core, 2-sigma outlier, and regression methods. We also estimate the ecological risks of heavy metals for surface sediments collected from the Bohai Sea using the three methods mentioned above. Ecological risks of heavy metals calculated using the regression method show wide disparities and significant differences from those calculated using the sediment core and 2-sigma methods, indicating that the regression method is not suitable for the Bohai Sea, likely as a result of its complex sources. Conversely, the estimated ecological risks using the sediment core method are moderate, and most heavy metals, except for Hg and Cd, have negligible contamination. • Regional metal (Fig. 1) backgrounds in the semi-closed Bohai Sea sediments are determined. • Three methods are used to determine metal backgrounds. • Regression is not suitable to determine metal backgrounds of Bohai Sea sediments. • Pollution levels of Bohai Sea sediments may be overestimated in previous studies. [ABSTRACT FROM AUTHOR]

Carbon supported PtRu core–shell catalyst is prepared by a facile and efficient method, in which the Ru nanoparticles are prepared with microwave-assisted method followed by in-situ reduction of Pt on Ru nanoparticles forming the PtRu core–shell structure. The catalyst is characterized by energy-dispersive X-ray spectroscope (EDX) analyzer attached to scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The TEM results show that the synthesized PtRu/C catalysts have small particle size and narrow size distribution. The PtRu/C catalyst shows higher electrochemical performance toward ethanol oxidation reaction (EOR) compared with methanol oxidation reaction (MOR). Notably, the PtRu/C catalysts exhibit higher mass activity and stability than that of the commercial PtRu/C (JM) catalyst for ethanol electrooxidation. [ABSTRACT FROM AUTHOR]

This work reports the preparation of hollow PtRu core–shell catalysts with TiO 2 as template, in which the Pt nanoparticles (NPs) grow on the exterior surface of Ru layer. The quantity of Pt NPs is easily tailored to control the integrity of Pt shell through varying the concentration of H 2 PtCl 6 solution. Scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and selected-area electron diffraction (SAED) are used to characterize the structure and morphology of H–PtRu. The core–shell structure is confirmed by the high-angle annular dark-field scanning TEM (HAADF-STEM) with energy-disperse X-ray spectroscopy (EDX). The electrochemical performance of H–PtRu is investigated by cyclic voltammetry and chronoamperometry. Results show that the catalytic activity of H–PtRu toward methanol oxidation reaction (MOR) is ∼2.5 times higher than that of Pt/C (JM), and the electrocatalytic stability improves with the increase of Ru content. Furthermore, H–PtRu exhibits better stability for methanol oxidation compared to Pt/C (JM) and PtRu/C (JM). [ABSTRACT FROM AUTHOR]

A facile synthetic route was employed to prepare double-shell PtRu/TiO 2 catalyst successfully without any stabilizer, in which Ru precursor was reduced by microwave and Pt precursor was in-situ reduced on Ru/TiO 2 using l -ascorbic acid as the soft reductant. The morphology, structure and composition of as-prepared catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis of X-ray (EDX), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry and chronoamperometry demonstrate the enhancement of electrocatalytic activity and stability towards the methanol electrooxidation of PtRu/TiO 2 in comparison with Pt/TiO 2 , Pt/C (JM) and PtRu/C (JM). Furthermore, the activity for methanol oxidation reaction (MOR) is much higher in alkaline media than that in acidic media. The improved activity and stability could be attributed to the synergetic effects of Pt–Ru and the electrochemically stable TiO 2 . [ABSTRACT FROM AUTHOR]

A novel approach was developed to synthesize smart shape-controlled PNIPAM/CS/Fe 3 O 4 microgels with uniform size. Interestingly, the microgels in spindle-shaped, cuboid and spherical morphologies were successfully prepared using the micro-emulsion polymerization at a low temperature from 28 to 40 °C based on the theory of “coil-to-globule”. The morphology and properties of the as-prepared products were investigated using scanning electron microscope (SEM), dynamic light scattering (DLS) and superconducting quantum interference device (SQUID). Results revealed that the PNIPAM/CS/Fe 3 O 4 microgels exhibited good thermo- and pH-sensitivities, and the size of the microgels decreased sharply upon increasing the temperature around 32 °C. The microgels with various shapes show a great promise in bioseparation and many other fields in the future. [ABSTRACT FROM AUTHOR]

In the work, hollow nanoporous Au/Pt core–shell (H-PtAu) catalysts with nanochannels were prepared with different sizes of gold nanoparticles of a narrow size distribution in the range of 1.8 ± 0.3, 3.2 ± 0.3 and 4.6 ± 0.5 nm. The hollow spheres were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and an energy-dispersive X-ray (EDX) analyzer. The electrochemical methods by cyclic voltammetric and chronoamperometry demonstrate that the catalytic performance of hollow nanoporous Au/Pt sphere electrocatalysts increases with the decrease of Au particles size in the samples. The nanoporous hollow structure of the electrocatalysts improves the efficiency for electro-oxidation of methanol and ethanol. More importantly, the nanoporous H-PtAu electrocatalysts have a higher catalytic activity and better steady-state performance for ethanol oxidation than methanol. [ABSTRACT FROM AUTHOR]

Studies have reported that various hydrocarbons and hydrocarbon-degrading bacteria are found in global deep-sea hydrothermal regions. However, little is known about degradation characteristics of culturable hydrocarbon-degrading bacteria from these regions. We speculate that these bacteria can be used as resources for the bioremediation of oil pollution. In this study, six oil-degrading consortia were obtained from the hydrothermal region of the Southern Mid-Atlantic Ridge through room-temperature enrichment experiments. The dominant oil-degrading bacteria belonged to Nitratireductor , Pseudonocardia , Brevundimonas and Acinetobacter. More varieties of hydrocarbon-degrading bacteria were obtained from sediments (preserved at 4 °C) near hydrothermal vents. Most strains had the ability to degrade high molecular weight petroleum components. In addition, Pseudonocardia was shown to exhibit a high degradation ability for phytane and pristine for the first time. This study may provide new insights into the community structure and biodiversity of culturable oil-degrading bacteria in deep-sea hydrothermal regions. [Display omitted] • The oil-degrading bacteria isolated from the sediment sample in NHV exhibited a high-degradation ability for phytane and pristane, with degradation rates higher than 86%. • Erythrobacter , Nitratireductor , Acinetobacter , Pseudonocardia and Brevundimonas were dominant oil-degrading bacteria in sediments of deep-sea hydrothermal region. • The diversity of oil-degrading bacteria in NHV was higher. We obtained more culturable oil-degrading bacteria from NHV stored at 4 °C. [ABSTRACT FROM AUTHOR]

The heavy metal contents (Cr, Cu, Zn, Cd, Pb, Hg, and As) of 88 surface sediment samples from the western Sunda Shelf were analyzed to determine their spatial distribution patterns and contamination status. The results demonstrated that high enrichment regions of heavy metals were focused in the Kelantan, Pahang, and Ambat river estuaries, and deep water regions of the study area. These high enrichment regions were mainly controlled by riverine inputs and their hydrodynamic conditions. The enrichment factor (EF), geoaccumulation index (I geo), and potential ecological risk index (PERI) were used to assess heavy metal accumulation. The results indicated that the study area was not significantly contaminated overall at the time of the study; however, Cd, As, and Hg were at levels corresponding to moderate contamination at many stations located in the Pahang River estuary, Kelantan River estuary, and north-eastern region of the study area, primarily because of anthropogenic activities. • The heavy metal contents of surface sediment samples from the western Sunda Shelf were analyzed. • High heavy metal enrichment regions were mainly controlled by riverine inputs and hydrodynamic conditions. • The western Sunda Shelf was not significantly contaminated overall at the time of the study. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have increased lead (Pb) emissions and impacted their spatiotemporal distributions in coastal seas. To quantify the increasing variability of Pb and identify the specific origins and their corresponding magnitudes, Pb and Pb isotopes are investigated in a well-placed sediment core covering the period of 1928–2008 in the Central Yellow Sea Mud (CYSM). The concentration of Pb varied from 27.17 μg/g to 37.30 μg/g upwardly along the core, with pronounced anthropogenic disturbance since the late 1960s. The Pb input history of the CYSM experienced five stages according to industrialization levels and Pb contamination, with relative pristine stages from 1928 to 1969 and human activity-impacted stages from 1969 to 2008. The 206Pb/207Pb ratio demonstrated an overall decreasing profile while the 208Pb/206Pb ratio displayed the reverse trend upwardly along the core, possibly due to the atmospheric delivery of anthropogenic Pb emissions from northern China. Furthermore, 208Pb/206Pb vs. 206Pb/207Pb shows certain linearity between natural sediment sources and anthropogenic emissions of Pb (atmospheric deposition); thus, atmospheric inputs account for 34–43% of the Pb in the sediment since Pb enrichment using the two-endmember mixing model. Moreover, the steep decrease in 206Pb/207Pb and rapid increase in 208Pb/206Pb since the 1970s suggest the introduction of leaded gasoline and the increasing proportionate consumption of gasoline relative to total energy consumption. The continuously decreasing 206Pb/207Pb ratio and increasing 208Pb/206Pb ratio since 2000 are the combined results of coal consumption, nonferrous smelting, and residual Pb contamination from leaded gasoline, which is quite distinctive from cases in North America and Europe. The relatively high 206Pb/207Pb and low 208Pb/206Pb ratios before 1969 represent the natural Pb isotopic signatures. Hence, Pb input is significantly affected by regional energy consumption and restructuring, and the Pb isotopic ratios may be a potential proxy for the shift in energy consumption. Image 1 • Five stages of Pb input are divided in the CYSM during 1928–2008. • Aeolian Pb from China's fossil fuel combustion leads to Pb enrichment in the CYSM. • Atmospheric deposition accounts for 34–43% of the Pb in the CYSM since late 1960s. • Energy consumption and restructuring impact the Pb isotopic ratios. • Pb isotopic ratios may be a potential proxy for the shift of energy consumption. Pb isotopic ratios in the Central Yellow Sea Mud preserve the footprint of land energy activities and can be used as a potential proxy for the shift in energy consumption. [ABSTRACT FROM AUTHOR]

Nanofiltration (NF) membranes are widely used in many fields, including food, petrochemical and brackish water desalination. One of the challenges for preparing NF membranes is to make NF membranes with high both permeability and selectivity because of the "trade-off" effect. To weaken or break through the "trade-off" effect, the thin film composite (TFC) NF membranes with high permeability and selectivity were prepared by constructing porous organic polymers (POPs) interlayers via diazo coupling reaction in the wild condition. The effects of the monomers ratio used to prepare POPs interlayers on the separation performance of the as-prepared TFC NF membranes as well as on the surface characteristics of substrate and polyamide (PA) separation layer were investigated. Due to hydrogen bonding, the POPs interlayers with hydroxyl groups slow down the diffusion rate of PIP molecules, which changes the surface structure of the polyamide (PA) separation layer from the nodular structure to the folded structure that favors increased permeability. The pure water permeance of the optimal TFC-S4 membrane (47.5 ± 0.3 L m−2 h−1 bar−1) is 3.8 times higher than that of the commercial polyamide nanofiltration membrane NF270 (12.5 L m−2 h−1 bar−1). Na 2 SO 4 rejection of the TFC-S4 membrane is 98.7 ± 0.1 %, which is greater than that of NF270 (96 %). This study provides ideas for future applications of POPs materials in NF membranes desalination. [Display omitted] • Constructing POPs interlayers through diazo coupling reaction is effective strategy. • High performance of TFC NF membranes were fabricated by POPs interlayers. • POPs interlayers with –OH are helpful to store amine molecules and inhibit diffusion. • TFC-S4 presents 47.5 L m−2 h−1 bar−1 pure water permeance and 98.7 % Na 2 SO 4 rejection. [ABSTRACT FROM AUTHOR]

In this study, we analyzed heavy metals in 404 surface sediment samples from the Bohai Sea to measure contamination status and distribution. We found Zn levels to be the highest, whereas Hg concentrations were the lowest of measured heavy metals. We found that the samples containing the most heavy metals were those collected from Fuzhou Bay, Jinzhou Bay, central Bohai Sea mud area, and the Yellow River Delta. Further analyses suggest that these heavy metals in surface sediments in the Jinzhou Bay and Fuzhou Bay pose a serious ecological risk, with substantial Cd and Hg accumulation in the Jinzhou Bay and Yellow River Delta regions being indicative of intense human activities. • Eight heavy metals of 404 surface sediments from the Bohai Sea were analyzed. • The mean heavy metal concentrations detected were, in descending order: Zn > Cr > Ni > Pb > Cu > As > Cd > Hg. • Samples containing the most heavy metals were those collected from Fuzhou Bay, Jinzhou Bay, central Bohai Sea mud area, and the Yellow River Delta. • Heavy metals in surface sediments in the Jinzhou Bay and Fuzhou Bay pose a serious ecological risk. [ABSTRACT FROM AUTHOR]

The present study aims to examine the distribution, sources and potential risks of toxic metals in the northern Bay of Bengal, Bangladesh. We found Cu, Pb, Zn and Hg exhibited similar spatial distribution pattern. Influenced by the Ganges-Brahmaputra River and the Karnafuli River, there were higher concentrations of these metals associated with the finer sediment and higher TOC in the northeastern portion of the study area. Moreover, coal transportation was assumed to account for the distinctive spatial distribution of As with higher concentration down the Port of Chittagong in the eastern boundary. Chemical-screening level assessment demonstrated the majority of the metals exceeded the threshold effect values, indicating certain possibility of adverse effect. The concentrations of Ni were higher than the possible hazardous values, suggesting high possibility of harmful consequences. The uncontaminated sediments mainly distributed in northwestern and the central portions affected by the delta erosion and marine transported sediments. • Eight toxic metals were studied in the northern Bay of Bengal, Bangladesh. • Ganges-Brahmaputra River and the Karnafuli River are the main metal sources. • Coal transportation accounts for the high As content down the Port of Chittagong. • Metal contamination in this area should receive considerable attention. [ABSTRACT FROM AUTHOR]

To understand the modern sedimentation and land-sea interaction processes in the Asian margin seas, we analyze rare earth element contents (REE, i.e., La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and grain sizes, detrital minerals from 158 surface sediment samples collected from the western Gulf of Thailand (GoT). The results reveal that the REE contents ranged from 25.42 μg/g to 201.21 μg/g, with an average value of 137.21 μg/g, and that the GoT is characterized by higher accumulations of LREE relative to HREE, together with negative Eu anomalies. Based on the spatial distribution characteristics of REE contents, δCe and δEu, the western GoT can be classified into three geochemical provinces. The Province I covers the northern and northwestern coastal zones of the GoT, including the entire upper GoT; its coarse size fraction and distribution pattern of hornblende- and quartz-dominated minerals caused REE contents to be the lowest, and these sediments were mainly derived from the rivers around the upper GoT, including the Chao Praya River and the Kea Klong River. The Province II is located in the central GoT and has the highest REE concentrations due to finer sediment composition and higher contents of zircon, authigenic pyrite, and biogenetic limestone. The Province II has two accumulation centers around Samui Island and Koh Chang Island, with REE spatial distribution influenced by the seasonal setting and mixed derived from multiple provenances around the GoT. The Province Ш is located in the lower GoT, close to Malaysia. The sediment type in this region is similar to that of Province I except for different detrital mineral compositions, especially the presence of siderite that is responsible for higher REE contents. The sediments in this region exhibits similar distribution patterns to those of terrestrial materials from the Malaysian peninsula such as that from the Kelantan River. The transportation processes of sediments in this region are mainly controlled by the coastal current. [ABSTRACT FROM AUTHOR]

In this work, bimetallic NiPd hollow nanoporous (H NiPd) catalysts are prepared by in-situ deposition of Pd nanoparticles (Pd NPs) on hollow Ni (H Ni) microspheres. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) reveal the hollow nanoporous essence of H NiPd catalysts. Meanwhile, using high-angle annular dark-field scanning TEM (HAADF-STEM) and elemental mapping, it is found that tiny dendritic-like NiPd nanocomposites attach on the exterior of microspheres. The content of Pd is easily tailored to constitute H NiPd catalysts with different Ni/Pd atomic ratios. Further electrochemical evaluation vindicates that the as-prepared H NiPd catalysts have a good catalytic activity and stability toward ethanol oxidation reaction (EOR) in alkaline medium. Notably, the peak current density of H Ni 3.1 Pd catalyst and the chronoamperometric current density of H Ni 4.6 Pd catalyst are 4 and 2 times of Pd/C (JM) catalyst, respectively, which show that H NiPd catalysts hold great potential in application of alkaline direct ethanol fuel cells (DEFCs). [ABSTRACT FROM AUTHOR]

As the main heat and water mass sources, the warm and saline Pacific waters have significant influence on sea ice and intermediate water circulation in the Sea of Okhotsk (SO). However, the long-term history of Pacific warm water intrusion into the SO remains unknown, impeding accurate predictions of its future changes. In this study, provenance proxies (clay mineral assemblages and trace element ratios (<2 μm)) from surface sediments and Site LV87-55-1 were used to investigate the history of Pacific water intrusion into the SO over the past 20 kyr. Provenance analysis indicates that sediments in the central SO primarily originated from the Amur River before 11.7 ka, with a significant rise in sediment input from the Kamchatka Peninsula since that time. By integrating published data on sediment grain size, sea surface temperature (SST), and sea-ice diatoms, we observed that the enhanced inflow of Pacific warm water into the SO led to intensified counterclockwise surface currents and the retreat of sea ice since the early Holocene, which subsequently resulted in a noticeable shift in sediment sources in the central SO. Furthermore, based on modern observation and TraCE-21 model simulations, we deduce that the intensified Aleutian Low (AL) since the early Holocene stimulated the East Kamchatka Current (EKC) through increased Sverdrup transport caused by cyclonic wind patterns. This, in turn, facilitated greater intrusion of Pacific warm water into the SO. Overall, our findings suggest an increase in Pacific warm water intrusion into the SO under future global warming scenarios, potentially posing a significant threat to the marine environment of both the SO and the subarctic Pacific. • Provenance records indicate enhanced intrusion of Pacific water into the SO since 11.7 ka. • Increased warm water intrusion results from enhanced Aleutian Low since 11.7 ka. • Future warming climate would stimulate more Pacific water intrusion into the SO. [ABSTRACT FROM AUTHOR]