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Gas–water interface mediated photoconversion of renewable biomass into fuels is a promising strategy to mitigate the impending environmental pollution and energy crisis. Herein, a gas–water interface is engineered to photoconvert fatty acids (FAs, C6–C9) into gaseous Cn-2 linear alpha-olefins (LAOs) with a high selectivity (87–91%) under mild conditions; especially, experiments with different interfaces demonstrate that the gas–water interface plays a crucial role in the enhanced selective production. The thinner molecular layer and ordered packing significantly promote the production of LAOs by maximizing the hydrogen bonding between FAs and interfacial water molecules. Furthermore, density functional theory (DFT) calculations, at the molecular level, elaborate that interfacial water could activate the reactions through hydrogen bonding lowering the reaction barrier of initial photoreaction of FAs. Additionally, different atmospheres are found to impact the pathways and products of photoconversion, thus enabling the controllable synthesis of LAOs. Unlike the metal/enzyme-involved harsh catalytic system, the gas–water interface serves as a green, low-cost and efficient 'venue' which can be infinitely reused for hydrocarbon production, pioneering a new way for mitigating the energy crisis and developing a truly green and sustainable society. [ABSTRACT FROM AUTHOR]

Glial cell-derived neurotrophic factor (GDNF) is reported to promote the survival of neurons and salivary gland regeneration after radiation damage. This study investigated the effect of GDNF on cell migration, growth, and response to radiation in preclinical models of head and neck squamous cell carcinoma (HNSCC) and correlated GDNF expression to treatment outcomes in HNSCC patients. Our ultimate goal is to determine whether systemic administration of GDNF at high dose is safe for the management of hyposalivation or xerostomia in HNSCC patients. Three HPV-positive and three HPV-negative cell lines were examined for cell migration, growth, and clonogenic survival in vitro and tumor growth assay in vivo. Immunohistochemical staining of GDNF, its receptors GFRα1 and its co-receptor RET was performed on two independent HNSCC tissue microarrays (TMA) and correlated to treatment outcomes. Results showed that GDNF only enhanced cell migration in two HPV-positive cells at supra-physiologic doses, but not in HPV-negative cells. GDNF did not increase cell survival in the tested cell lines post-irradiation. Likewise, GDNF treatment affected neither tumor growth in vitro nor response to radiation in xenografts in two HPV-positive and two HPV-negative HNSCC models. High stromal expression of GDNF protein was associated with worse overall survival in HPV-negative HNSCC on multivariate analysis in a combined cohort of patients from Stanford University (n = 82) and Washington University (n = 189); however, the association between GDNF gene expression and worse survival was not confirmed in a separate group of HPV-negative HNSCC patients identified from the Cancer Genome Atlas (TCGA) database. Based on these data, we do not believe that GNDF is a safe systemic treatment to prevent or treat xerostomia in HNSCC and a local delivery approach such as intraglandular injection needs to be explored. [ABSTRACT FROM AUTHOR]

In this work, electrochemical impedance spectroscopy (EIS) was utilized to probe interfacial structures of antifouling anion exchange membranes (AEMs) with different modifying architectures fabricated by graphene oxide (GO) and polydopamine (PDA). Results showed that the GO@PDA modified AEMs with a compact GO@PDA layer exhibited a new interface between the modifying layer and membrane matrix, different from the loose GO-modified AEMs. After fouling experiments, from quantifying electrical equivalent circuits fitted to EIS results, it could be found that GO-modified AEMs and PDA-modified AEMs exhibited a significant foulants layer, although the modifying layer reduced the amount of foulants absorbed in the membrane matrix. For GO@PDA-modified AEMs, the increase in ohmic resistance and the foulants layer was almost negligible. Only a small amount of foulants accumulating on the GO@PDA layer affected the capacitive resistance of the interfacial layer obviously. It was concluded that the electrochemical properties and interface of modified AEMs was influenced by the structure of modifying layer, and a dense and compact modifying layer could be more effective to block the foulants from depositing on the surface of AEMs and entering the membrane matrix. The electrochemical characterizations helped to elucidate the antifouling mechanism of modified AEMs with different structures and get a good understanding of the correlation among the properties, structures, and antifouling performance of the modifying layer. [ABSTRACT FROM AUTHOR]

Recycling of spent lithium-ion batteries (LIBs) has attracted intensive attention owing to their potential environmental risk and the importance of the supply of critical metals. Sulfation roasting as a traditional technology is not considered environmentally friendly due to serious SOx emission. The usage of over-stoichiometric amounts of sodium salt results in high sodium content in the leaching solutions bringing about difficulties for the preparation of qualified lithium products. It is usually not easy to achieve high recovery selectivity of metals. Herein, we find it is possible to eliminate secondary emission and no sodium is included in the process of spent LIB (LiCoO2 as a case study) recycling if the transfer pathway of sulfur among different phases is well controlled. At the same time, high lithium recovery selectivity is achieved. The principles of green chemistry for substitution of chemicals with a low environmental impact and improving the atomic efficiency of sulfur are introduced during traditional sulfation roasting. A pretreatment step of aging with sulfuric acid at 393 K is introduced to form cobalt sulfate which in the following heat treatment step will further preferentially react with the remaining LiCoO2 until it is completely consumed. By controlling the amount of sulfuric acid, sulfur can be recirculated and recycled thoroughly in the form of SO42−, instead of SOx emission and the atomic efficiency of sulfur can be highly improved. After leaching with water, the concentration of Li+ in the leachate reaches 19.82 g L−1; 99.3% lithium and 98.7% cobalt were recuperated as Li2CO3 and Co3O4 with a purity of 99.89% and 99.95%, respectively. Our findings propose an environmentally benign and easily implemented strategy for selective recycling of spent LIBs. The fundamentals provide inspiration for separation and extraction fields such as mining and recycling of complex systems composed of multiple metals. [ABSTRACT FROM AUTHOR]

Abstract Daily PM 2.5 was collected in the periods before, during and after the Chinese Spring Festival (CSF) in both 2016 and 2018 to clarify the annual variation in the concentrations and health risks of toxic metals under different firework/firecracker (FF) management strategies. PM 2.5 and bound metals all decreased during the CSF from 2016 to 2018. According to relative abundance analysis, toxic metals, i.e., Ba, Pb, Cu and Cr, showed obvious peak concentrations and abundance levels on intensive FF burning days, i.e., New Year's Eve, Chinese New Year and the Lunar Festival. In both CSF periods, three sources of toxic metals, namely, FF burning, coal combustion, and resuspended dust and vehicle emissions, were identified by positive matrix factorization (PMF). Among them, the mass contribution of FF decreased from 0.83 μg m−3 (11%) in the 2016 CSF to 0.23 μg m−3 (9.0%) in the 2018 CSF. The FF-attributed noncancer and cancer risks due to metals for residents under long-term exposure were 0.02 (19.9%) and 1.76 × 10−7 (17.9%) in the 2016 CSF and 0.01 (20.2%) and 8.59 × 10−8 (14.7%) in the 2018 CSF. Although a policy shift from "restriction" to "prohibition" regarding FF has indeed decreased toxic metal concentrations and health risk, Cr(VI) and Ba should be examined more closely in the future because they have become dominant contributors to cancer risk and noncancer risk, respectively. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

Abstract PM 2.5 -bound PAHs are ubiquitous in urban atmospheres and are characterized as carcinogenic, teratogenic and mutagenic upon inhalation. A total of 218 daily PM 2.5 samples were collected during one year in the urban district of Beijing, China. Analysis showed that the annual mean concentration of total PAHs (TPAHs) was 66.2 ng/m3, with benzo(a)pyrene (BaP) accounting for 12.4%. High-molecular-weight (HMW, 4–6 rings) PAHs were the dominant components. Seasonal TPAH concentrations decreased in the order of heating season (156 ng/m3) > autumn (20.4 ng/m3) > spring (16.0 ng/m3) > summer (12.5 ng/m3) and were related to meteorological conditions and source emission intensity. The source-attributed mass contribution and source regions of three sources (i.e., (1) vehicle emissions; (2) coal combustion; and (3) petroleum volatilization, natural gas and biomass combustion) were identified by integrating the positive matrix factorization (PMF), potential source contribution function (PSCF) and conditional probability function (CPF). Vehicle emissions contributed the most mass (54.6%), followed by coal combustion (29.8%), on an annual basis. Combined with actual regional emissions, vehicle emissions were mainly derived from local sources, while coal combustion mainly came from regional transport from surrounding areas. Vehicle emissions and coal combustion have much higher mass contributions in the heating season. The source-attributed cancer risk was further evaluated based on source mass contribution and inhalation unit risk. Vehicle emissions contributed the largest risk (2.8 × 10−6, accounting for 71%) as a result of 30 years of exposure for local residents, exceeding the acceptable level (10−6). The heating season showed the most risk, especially in response to vehicle emissions and coal combustion. Overall, the source-attributed cancer risk was regarded as the better index for the development of a control strategy of PM 2.5 -bound PAHs for protecting residents. Based on this index, priority control sources in each season were identified to supply a more effective management solution. Graphical abstract Image 1 Highlights • PAH concentrations were much higher in the heating season than in the other seasons. • Seasonal variations were related to meteorological conditions and source emissions. • The PMF-PSCF CPF model improved source apportionment and provided the source region. • Three sources were identified, and vehicle emission contributed ¾ of the cancer risk. • Source-attributed cancer risk was suggested for ranking priority control sources. An integrated PMF-PSCF CPF model was proposed to decrease the uncertainty of quantitative source apportionment of PM 2.5 -bound PAHs and identify potential source regions, and source-attributed health risk was suggested as a better index than mass contribution for ranking priority control sources of PM 2.5 -bound PAHs. [ABSTRACT FROM AUTHOR]

An appropriate co-catalyst can significantly promote the photocatalytic efficacy, but this has been seldom studied in the visible-light photocatalysis combined with ozone, namely photocatalytic ozonation. In this work, a dendritic bismuth vanadium tetraoxide (BiVO4) material composited with highly dispersed MnOx nanoparticles was synthesized, and its catalytic activity is 86.6% higher than bare BiVO4 in a visible light and ozone combined process. Catalytic ozonation experiments, ultraviolet- visible (UV-Vis) diffuse reflectance spectra and photoluminescence spectra jointly indicate that MnOx plays a triple role in this process. MnOx strengthens the light adsorption and promotes the charge separation on the composite material, and it also shows good activity in catalytic ozonation. The key reactive species in this process is $OH, and various pathways for its generation in this process is proposed. This work provides a new direction of catalyst preparation and pushes forward the application of photocatalytic ozonation in water treatment. [ABSTRACT FROM AUTHOR]

Fluorescent nanoarchitectures, such as hydrophobic micelles and hydrophilic vesicles decorated with fluorescent carbon nanoparticles, were fabricated from one fatty acid by means of photo-triggering. The biomimetic nanostructures, like cell membrane structures, have applications in fluorescence imaging in both the cell cytoplasm and nucleus. Besides, hydrophobic micelles can be used as very stable fluorescent inks. [ABSTRACT FROM AUTHOR]

Purpose: The main objective of this study was to develop a technique to accurately determine the air gap between the end of the proton beam compensator and the body of the patient in proton radiotherapy. Methods: Orthogonal x‐ray image‐based automatic coordinate reconstruction was used to determine the air gap between the patient body surface contour and the end of beam nozzle in proton radiotherapy. To be able to clearly identify the patient body surface contour on the orthogonal images, a radiopaque wire was placed on the skin surface of the patient as a surrogate. In order to validate this method, a Rando® head phantom was scanned and five proton plans were generated on a Mevion S250 Proton machine with various air gaps in Varian Eclipse Treatment Planning Systems (TPS). When setting up the phantom in a treatment room, a solder wire was placed on the surface of the phantom closest to the beam nozzle with the knowledge of the beam geometry in the plan. After the phantom positioning was verified using orthogonal kV imaging, the last pair of setup kV images was used to segment the solder wire and the in‐room coordinates of the wire were reconstructed using a back‐projection algorithm. Using the wire as a surrogate of the body surface, we calculated the air gaps by finding the minimum distance between the reconstructed wire and the end of the compensator. The methodology was also verified and validated on clinical cases. Results: On the phantom study, the air gap values derived with the automatic reconstruction method were found to be within 1.1 mm difference from the planned values for proton beams with air gaps of 85.0, 100.0, 150.0, 180.0, and 200.0 mm. The reconstruction technique determined air gaps for a patient in two clinical treatment sessions were 38.4 and 41.8 mm, respectively, for a 40 mm planned air gap, and confirmed by manual measurements. There was strong agreement between the calculated values and the automatically measured values, and between the automatically and manually measured values. Conclusions: An image‐based automatic method has been developed to conveniently determine the air gap of a proton beam, directly using the orthogonal images for patient positioning without adding additional imaging dose to the patient. The method provides an objective, accurate, and efficient way to confirm the target depth at treatment to ensure desired target coverage and normal tissue sparing. [ABSTRACT FROM AUTHOR]

Arsenic (As) is a well-known carcinogenic substance whose biological toxicity in soils and plants depends on its concentration and chemical forms. Silicon (Si) generally can alleviate biotic and abiotic stresses, including As stress. However, its effects vary depending on As chemical form, plant species and other factors. A pot experiment was performed to investigate the effects of Si addition on the content and forms of As in red soil and its uptake, transport and speciation in Panax notoginseng . The results showed that additions of 25 and 75 mg kg −1 of Si both significantly decreased the concentrations of water-soluble As and exchangeable As in soil and therefore decreased the bioavailability of soil As. However, the As uptake by Panax notoginseng (PN) was increased, which resulted in increases in As concentration by 18.5% and 2.3% in roots and by 56.7% and 58.3% in shoots, respectively, when compared with the control. Arsenate (As(V)) was the dominant As species in all the treatment soils (99.8–100%), whereas arsenite (As(III)) was prevalent in plant roots (75.2–92.4%), shoots (74.1–87.9%) and leaves (73.9–84.3%). Si addition (25 and 75 mg kg −1 ) significantly increased As(III) concentration in roots by 167.5% and 83.3%, respectively. Monomethylarsonic acid (MMA) was the only detected methylated As but at low concentrations (0.01–0.29 mg kg −1 ) and only in PN leaves. Si addition (25 and 75 mg kg −1 ) significantly increased the copy number of the arsenite methyltransferase ( arsM ) gene by 31.0% and 47.2% but did not increase the methylated As species content in PN leaves. The detected copy number of the arsM gene did not represent the capacity of soil to methylate As, and the sources of MMA in leaves need to be explored in further research. [ABSTRACT FROM AUTHOR]

In recent years, the recovery of metals from spent lithium ion batteries (LIBs) has become increasingly important due to their great environmental impact and the wastage of valuable metallic resources. Among different types of spent LIBs, processing and recycling the spent LiFePO4 batteries are challenging because of their relatively low extraction efficiency and recycling selectivity of valuable metal(s) and great potential for secondary waste generation. In this research, an effective and sustainable approach for selective leaching of lithium from spent LiFePO4 batteries was demonstrated. By properly adjusting or controlling the oxidative state and proton activity of the leaching solution, lithium was found to be selectively leached with a high recovery efficiency. The aluminium remained in the metallic form and iron as FePO4 in the solid residue which can be easily separated by sieving. The effects of a range of parameters (i.e. acid concentration, initial volume fraction of the oxidant, liquid-to-solid ratio, reaction temperature and time) during lithium leaching were comprehensively investigated. The selective reaction mechanisms were clarified and the controlling step for the leaching kinetics was identified. Based on the laboratory scale results, a pilot batch process was developed and simulated. The process is found to be techno-economically feasible and environmentally friendly for recycling of spent LiFePO4 batteries using selective leaching. High purity Li2CO3 (99.95 wt%) could be obtained with a high recovery rate. This research demonstrates the possibility of improving the metal recycling effectiveness from spent LiFePO4 batteries by incorporating the principles of green chemistry and probably contributes to the sustainability of the lithium ion battery industry. [ABSTRACT FROM AUTHOR]

Insulin-like growth factor-1 receptor (IGF-1R) is a cell membrane receptor involved in cell proliferation and apoptosis, which is highly expressed in lung squamous cell carcinoma (SCC). The present study aimed to observe the influence of IGF-1R silencing on the radiosensitivity of SCC and investigate the potential mechanisms involved. Human lung SCC H520 cells with relatively high expression of IGF-1R were used. IGF-1R expression was silenced using short hairpin RNA. The influence of IGF-1R silencing on radiosensitivity and apoptosis was assessed using a clone formation assay and flow cytometry. The expression levels of proteins relevant in DNA damage repair and hypoxic signaling pathways were analyzed using western blotting. Decreased expression of IGF-1R led to an increase in the sensitivity of H520 cells to irradiation. Molecular analysis showed that the reduced expression of IGF-1R decreased the protein expression of ataxia-telangiectasia mutated (ATM), H2A histone family member X (H2AX) and p53 binding protein 1 (53BP1), which are associated with the DNA repair pathway. Furthermore, 53BP1 is also known to be involved in apoptosis. Proteins involved in the hypoxic pathway, including hypoxia inducible factor 1 α (HIF-1α), matrix metallopeptidase 9 (MMP-9) and vascular endothelial growth factor A (VEGFA) were also involved in the radiosensitivity. In conclusion, decreased expression of IGF-1R leads to improved radiosensitivity of SCC cells, and the underlying mechanism may be associated with the decreased expression of proteins involved in ATM/H2AX/53BP1 DNA damage repair and the HIF-1α/MMP-9 hypoxic pathway, which results in the induction of apoptosis and increased radiosensitivity. These findings suggest that targeting of IGF-1R may represent a novel approach for lung SCC radiation treatment. [ABSTRACT FROM AUTHOR]

Abstract: Amphiphilic nanoreactors have been recently used to fabricate photoluminescent carbon‐rich polymer nanodots (PCPNs). However, the applications of PCPNs have been limited by their requirements for high temperature and toxic organic solvents or catalysts and the difficult control of their luminescent properties. Herein, a novel and facile strategy is reported for the synthesis of controllable PCPNs. This strategy involves the use of in situ vesicular nanoreactors under mild photoirradiation with fatty acid as the precursor. The conjugation degree of the uniformly sized PCPNs can be increased by extending photoreaction time, thus enabling the tuning of the optical properties of PCPNs. The PCPNs, which feature controllable and outstanding luminescent properties, low cytotoxicity, and biocompatibility, are successfully applied in bioimaging and as fluorescent ink. The present strategy is an attractive and facile platform for the preparation of carbon‐rich nanomaterials with controllable photoluminescence. [ABSTRACT FROM AUTHOR]

Three kinds of graphitic carbon nitride materials (bulk, porous and nanosheet g-C 3 N 4 ) were composited with a multiwall carbon nanotube (MWCNT) by a hydrothermal method, and the obtained b-C 3 N 4 /CNT, p-C 3 N 4 /CNT and n-C 3 N 4 /CNT materials were used in the electrodes for electro-peroxone process. It was found that the n-C 3 N 4 /CNT composite exhibited the highest efficiency in oxalate degradation, though it performed the worst in the oxygen-reduction reaction for H 2 O 2 production. The n-C 3 N 4 /CNT composite exhibited higher activity than CNT and other composites in catalytic ozonation experiments, due to the higher pyrrolic-N content modified on the CNT surface and higher surface area. It also has higher electron transfer ability, which benefited to the electro-reduction of both O 2 and O 3 . The result confirmed that catalytic ozonation process was an important means to enhance the degradation efficiency in the electro-peroxone process, besides peroxone process and O 3 -electrolysis. [ABSTRACT FROM AUTHOR]

The extraction mechanism and the oxidation of extractants are essential to optimize the extraction process. To investigate the two problems for selective extraction of V(V) and Cr(VI), the extraction complexes of V(V) and Cr(VI) formed in the process of extraction with primary amines were obtained by solvent-out crystallization, respectively. The average compositions of the extraction complexes were determined by element analysis, X-ray photoelectron spectroscopy, and inductive couple plasma-optical emission spectrometry. The chemical functional groups of the extraction complexes were confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy. The structures of the extraction complexes of V(V) were speculated with their functional groups and average compositions. The hydrogen bond association mechanism of V(V) extraction was illustrated with the structure of the complexes, and the oxidation reaction of extractants with Cr(VI) was also demonstrated. According to the oxidation reaction of extractants with Cr(VI) and experiment conditions for the initial pH value, the optimized operation condition of the initial pH value ≥5.5 was determined to prevent the oxidation of extractants. The interaction of V(V) and Cr(VI) for the vanadium extraction and extractant oxidation was also investigated. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Abstract: A new hydrogen peroxide detection sensitive material, boron doped carbonized ZIF‐67@graphene (Co‐N/C@G‐B) is synthesized through pyrolysis of a sandwich‐like ZIF‐67 coating graphene material. After doping boron atoms by using chemical vapor deposition method, new active sites such as Co2B and BNC bonds are created, and mesopores are significantly increased. Most importantly, this Co‐N/C@G‐B material is found to exhibit excellent performance as an enzyme‐free biosensor for detecting hydrogen peroxide with a very wide detection range (from 0.5 × 10−6 to 60 × 10−3 m), a low detection limit (0.19 × 10−6 m), and a rapid response time (≈3 s). The prepared biosensor also shows strong anti‐interference ability in the complex working occasions. Furthermore, for real application of the materials, an electronic device of biosensor is developed by using technologies of screen printing electrode, integrated circuit, 3D printed shell, and custom‐developed program, which shows high sensitivity and portability to detect hydrogen peroxide. Such device paves a way for further practical application of advanced materials in commercial scale. [ABSTRACT FROM AUTHOR]

Lead is classified to be one of the top heavy metal pollutants in China. The corresponding environmental issues especially during the management of spent lead-acid battery have already caused significant public awareness and concern. This research gives a brief overview on the recycling situation based on an investigation of the lead industry in China and also the development of technologies for spent lead-acid batteries. The main principles and research focuses of different technologies including pyrometallurgy, hydrometallurgy and greener technologies are summarized and compared. Subsequently, the circulability of lead based on the entire life cycle analyses of lead-acid battery is calculated. By considering different recycling schemes, the recycling situation of spent lead-acid battery in China can be understood semi-quantitatively. According to this research, 30% of the primary lead production can be shut down that the lead production can still ensure consecutive life cycle operation of lead-acid battery, if proper management of the spent lead-acid battery is implemented according to current lead industry situation in China. This research provides a methodology on the view of lead circulability in the whole life cycle of a specific product and is aiming to contribute more quantitative guidelines for efficient organization of lead industry in China. [ABSTRACT FROM AUTHOR]

At present hollow nanostructures have been intensive topics of research due to their superior properties over their solid nano counterparts. In this study uniform size chromium hollow nanospheres were synthesized by polyol method followed by simple corrosion etching using a proper solvent combination strategy. Fourier transform infrared (FTIR) and UV Visible spectroscopy have been applied to follow the conversion of precursor into metal particles and then hollow nanospheres respectively. Particle size and morphology have been characterized by particle size analyzer and Field Emission Scanning Electron microscopy (FE SEM). The crystal structures of chromium species such as CrO2 and Cr2O3 resulted from CrOOH have been determined by X-ray diffraction technique (XRD). X-ray photoelectron spectroscopy (XPS) has been applied to evaluate the surface binding energy of chromium ions. Self arranged hollow nanospheres have shown temperature-dependent magnetization. In this way magnetic property of solid chromium nanospheres has been tuned by converting them into hollow nanospheres. [ABSTRACT FROM AUTHOR]

Catalytic ozonation is a highly effective method in wastewater treatment, and MnO 2 materials are widely recognized as active heterogeneous catalysts in this process. Many works reported the progress in active MnO 2 synthesis, but the active phase is rarely systematically studied. In this paper, all six phases of MnO 2 (α-, β-, δ-, γ-, λ- and ε-) were synthesized by facile methods. Their catalytic activities in ozonation of 4-nitrophenol (4-NP) were evaluated and correlated with the physicochemical properties obtained from X-ray Diffraction (XRD), transmission electron microscopy (TEM), physical adsorption and cyclic voltammetry (CV) analysis. α- MnO 2 was found to be the most active catalyst in 4-NP degradation at neutral pH. MnO 2 with low average oxidation state (AOS) showed stronger oxidation/reduction peaks in CV characterization, which benefited catalytic decomposition of ozone to generate active species. Superoxide radical was confirmed as the main oxidizing species, along with singlet oxygen and ozone molecule oxidation in bulk solution and little contribution of oxidation on the MnO 2 surface. Mn 2+ leaching happened during catalytic ozonation, but its catalytic role is negligible. This result may give rise to the preparation of new active MnO 2 catalysts. [ABSTRACT FROM AUTHOR]

Urbanization, which is characterized by population aggregation, industrial development, and increased traffic load, may change local polycyclic aromatic hydrocarbons (PAH) emissions and their associated health risks. To investigate these changes, we collected soil samples in 2009 and 2014 in a rapidly developing small town in Southern Jiangsu (China) and measured the concentrations of 16 PAHs via gas chromatography-mass spectrometry. Although the total PAHs decreased from 4586.6 to 640.6 ng/g, the concentrations of the high-molecular-weight PAHs benzo(b)fluoranthene and benzo(a)pyrene increased due to changes in the PAH sources. Source apportionment by positive matrix factorization indicated that the two sources responsible for the highest soil PAH contributions changed from biomass combustion (42%) and coal combustion (32%) in 2009 to coal, biomass and natural gas combustion (35%) and diesel combustion (33%) in 2014. However, the two sources with the highest associated health risks were diesel and gasoline combustion in both years. The incremental lifetime cancer risk for residents exposed to PAHs in the soil via incidental ingestion and dermal contact decreased from 1.75 × 10 − 6 to 1.60 × 10 − 6 . The ban on open burning of straw and the substitution of coal with natural gas offset the PAH health risks due to increased urbanization. [ABSTRACT FROM AUTHOR]

This work aimed to determine the effect of organic foulants and fouling behavior on separation of multi-ions for nanofiltration (NF) membrane. Three model organic foulants (bovine serum albumin, lysozyme, and humic acid) were selected and studied in depth. The rejections of mono- and di-anions by virgin membrane varied with different organic foulants because of foulant-enhanced co-ion competition. Subsequent multi-ions separations by fouled membranes were different due to the zeta potential and structure of the fouling cake. In contrast to the single protein system, Cl−andrejection was reduced by HA fouled membrane. However, with added proteins in the HA solution, mixed systems experienced decreasing Cl−rejection and increasingrejection. In addition, solution chemistry (solution pH, ionic strength, and Ca2+) had marked effect on the cake layer composition, likely due to the changing interaction between foulant and foulant, as well as between foulant and NF membrane. The suitable foulant cake structure could result enhanced in multi-ions separation. The synergistic mechanisms of organic foulants and cake were analyzed by calculated cake hydraulic resistance and zeta potential of fouled membranes. [ABSTRACT FROM AUTHOR]

The fouling behavior of nanofiltration (NF) membranes by proteins bovine serum album (BSA), lysozyme (LYS), and humic acids (HA), as well as their mixtures was studied in a cross flow bench-scale cell. The similarities and differences of the effects of pH on single and mixed organic foulant systems were compared by analyzing the size distribution and zeta potential of foulants in the feed, and in conjunction with the characterization of fouled NF membranes, respectively. Results showed that the fouling behaviors of both single and the mixed systems were significantly correlative with solution pH, moreover BSA/LYS combined with HA appeared more aggravated fouling behavior than single foulant within the test pH range. For solution pH, this can affect interactions of foulants–foulants and foulants–membrane by changing zeta potential of them. Also, therefore, zeta potential value could be used to predict the fouling behavior of NF. Considering the experimental results, more severe fouling behavior by not only single (HA, BSA, and LYS), but mixed systems (BSA + HA and LYS + HA) occurred at acidic and neutral solution pH. [ABSTRACT FROM PUBLISHER]

Experiments were conducted to investigate the concentrations of PAHs and their adsorption characteristics by activated sludge in this study. Influence of sorption time, sludge concentration, and pH on PAHs adsorption was evaluated. Furthermore, the isotherms, kinetics of adsorption, and potential risk were also explored. Experimental results show that concentrations of 16 PAHs in coking wastewater sludge were 581.600–2201.633 μg/g, both Linear and Freundlich adsorption models were able to adequately describe the adsorption equilibriums of PAHs onto activated sludge. The adsorption process closely followed the pseudo-second-order kinetic model. The adsorption efficiencies of PAHs depended on the activated sludge concentration and sorption time, while that was not affected by pH. Hydrophobic interaction, distribution, and chemisorption were mainly responsible for the adsorption of PAHs, while the surface area and pore volume of activated sludge had little contribution. Results also indicate that the order of carcinogenic health risk was Benzo[a]pyrene > Dibenzo[a,h]anthracene > Benzo[b]fluoranthene > Indeno[1,2,3-cd]pyrene > Benzo[a]anthracene > Benzo[k]fluoranthene. [ABSTRACT FROM PUBLISHER]

The commercialization of fuel cells and metal–air batteries can only be realized if expensive and scarce platinum-based catalysts are replaced by lower cost, efficient, and durable catalysts for the oxygen reduction reaction (ORR). Along with intensive research efforts in developing low-cost, metal-free catalysts to replace platinum-based catalysts, heteroatom doped graphitic carbon materials (especially graphene and carbon nanotubes) have been demonstrated to show superior ORR performance. However, graphdiyne, another member of the carbon family, has not been completely studied as an electrocatalyst for the ORR. We demonstrate here that nitrogen and fluorine co-doped, metal-free graphdiyne exhibits comparable electrocatalytic activity to commercial Pt/C both in half-cell and full-cell (primary Zn–air battery) tests, regarding its onset potential and limiting current density. Moreover, the new catalyst has better stability, as well as a higher tolerance to methanol crossover and CO poisoning effects, than the commercial Pt/C. [ABSTRACT FROM AUTHOR]