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Polymeric membrane ion-selective electrodes (ISEs) have been widely used in environmental monitoring. However, in complicated marine environments, marine biofouling usually becomes a sticky problem for these electrodes. Herein, for the first time, a novel maintenance-free antifouling potentiometric marine sensor based on a self-polishing coating (SPC) is proposed. The SPC is synthesized by using the seeded emulsion polymerization method based on the triisopropylsilyl methacrylate monomer as the regulator of the self-renewal rate. This coating can be simply modified onto the electrode surface by drop-casting. The silyl acrylate side groups of the obtained SPC on the sensor surface can be hydrolyzed in the marine alkaline medium. The shear movement of seawater driven by sea waves, wind, gravity, or vibration removes the leftover (fouled) brittle polymer backbone and thus the fouling marine microorganisms. As a proof-of-concept experiment, a polymeric membrane Ca2+-ISE is chosen as a model. Compared to the unmodified electrode, the SPC-coated Ca2+-ISE exhibits remarkable improved antifouling properties in terms of superior anti-adhesive abilities towards marine microorganisms, such as bacterial cells and algae and excellent long-term stability even in the presence of high levels of marine microorganisms. Since no additional manual maintenance is required for maintaining the antifouling abilities of the sensor, the proposed self-polishing sensor may lay an important foundation for construction of unattended long-term potentiometric monitoring systems in real marine environments. [ABSTRACT FROM AUTHOR]

Polymeric membrane ion-selective electrodes (ISEs) have been widely used in environmental monitoring. However, in complicated marine environments, marine biofouling usually becomes a sticky problem for these electrodes. Herein, for the first time, a novel maintenance-free antifouling potentiometric marine sensor based on a self-polishing coating (SPC) is proposed. The SPC is synthesized by using the seeded emulsion polymerization method based on the triisopropylsilyl methacrylate monomer as the regulator of the self-renewal rate. This coating can be simply modified onto the electrode surface by drop-casting. The silyl acrylate side groups of the obtained SPC on the sensor surface can be hydrolyzed in the marine alkaline medium. The shear movement of seawater driven by sea waves, wind, gravity, or vibration removes the leftover (fouled) brittle polymer backbone and thus the fouling marine microorganisms. As a proof-of-concept experiment, a polymeric membrane Ca2+-ISE is chosen as a model. Compared to the unmodified electrode, the SPC-coated Ca2+-ISE exhibits remarkable improved antifouling properties in terms of superior anti-adhesive abilities towards marine microorganisms, such as bacterial cells and algae and excellent long-term stability even in the presence of high levels of marine microorganisms. Since no additional manual maintenance is required for maintaining the antifouling abilities of the sensor, the proposed self-polishing sensor may lay an important foundation for construction of unattended long-term potentiometric monitoring systems in real marine environments. [ABSTRACT FROM AUTHOR]

Metasurfaces composed of subwavelength structure arrays provide a diverse and powerful platform for generation of complicated electromagnetic (EM) fields and wavefronts manipulation and have triggered an unprecedented research upsurge in electromagnetism with the development of computer‐generated holography (CGH). Different from conventional scalar holograms only containing amplitude and phase properties, a vectorial hologram that benefits from the maneuverability of polarization of EM fields exhibits more immeasurable application potential and is simultaneously regarded as an urgent requirement. In this work, assisted by single completely spin‐decoupled meta‐particles, which perfectly combine the functions of simultaneous and independent amplitude and phase modulation of orthogonal polarization states containing left‐ and right‐handed circularly polarized (LCP&RCP) components, a vectorial hologram induced through eigenstates degeneracy with the ability of encoding arbitrary polarization is proposed in the microwave region. As the proof of concept, eight distinct holograms with specified polarizations and six‐channel polarization‐multiplexed hologram display are fabricated and characterized, further showcaing the versatility of the approach for the customization of arbitraty polarization and integration of reconstructed patterns. With the advantages of multi‐controllability and ultra‐compactness, the constructed monolayer completely spin‐decoupled paradigm for vectorial regulation may find prospective application aspects in spin detection, target perception, multi‐channel data encryption, and many other related fields. [ABSTRACT FROM AUTHOR]

Vortex beam carrying orbital angular momentum (OAM) has been experiencing a research upsurge attributed to its excellent communication capability, which also boosts the development of the OAM technology and promotes the application of the OAM generator. However, most of the existing designs of the OAM generators can only produce a small number of diverse OAM modes, and restrict the channel capacity of single OAM generator. Herein, an appealing strategy of six‐mode OAM generator based on helicity‐assisted full‐space metasurface is proposed to generate up to six diverse OAM modes by altering the polarization state, illumination region, and incidence direction of incident waves. Significantly, the designed OAM generator has high communication security because of its great information entropy, and the generated OAM modes possess the characteristics of high purity and low crosstalk which result from the orthogonal polarization states and unequal deflection angles of produced vortex beams. A proof‐of‐concept prototype is constructed to corroborate the validity of our methodology, and the results of simulations and experiments are in excellent agreement with theoretical predictions. This fire‐new OAM generator will possess a promising application prospect in communication systems, and may also provide an efficacious method to design multifunctional devices. [ABSTRACT FROM AUTHOR]

Surface waves (SWs) can be coupled by phase gradient metasurfaces (PGMs) with high efficiency, but this methodology still suffers from inherent defects of narrow bandwidth, changeless coupled mode, difficult separation of hybrid modes SWs, and uncontrollable propagation direction. In this article, a series of innovative designs is proposed by combining different Pancharatnam–Berry (PB) PGMs with appointed phase distribution principles to resolve PGMs SWs couplers’ above problems. Both the simulated and measured results verify that the broadband conventional SWs coupler can couple transverse magnetic (TM) mode SWs under $x$ -polarized incidence and the broadband extraordinary SWs coupler can couple TM mode SWs under $y$ -polarized incidence in 8.5–11.5 GHz. By integrating these two SWs couplers, a bifunctional SWs coupler is obtained to couple TM mode SWs to the left and transverse electric (TE) mode SWs to the right simultaneously under $x$ -polarized incidence. Furthermore, another two SWs couplers are designed to excite TM mode SWs with 30° and 45° slant directions under $x$ -polarized incidence in 8.5–11.5 GHz, which indicates that coupled SWs’ wavefront direction can be controlled flexibly in a wide bandwidth. The above SWs couplers are proved to work with relatively high coupling efficiencies and have great potential in engineering applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The multichannel Airy beam generator can independently generate the Airy beams for circular polarized and linear polarized waves. • The multichannel beam focusing for circular polarized and linear polarized waves is realized by combining two multichannel Airy beam generators. • The multichannel Airy beam generator is constructed through the antenna theory analysis and the Jones matrix analysis. • The generated Airy beams possess the obvious diffraction-free, self-bending and self-healing features in the broad frequency band. • The low channel crosstalk ensures the high quality of the Airy beams generated simultaneously in three polarization channels. The Airy beam has intrigued long-held research interests and developed various striking applications attributed to the unprecedented diffraction-free, self-bending and self-healing properties. Metasurfaces with superior design freedom and small structure size open a fire-new avenue for generating efficient and broadband Airy beam. Nevertheless, most existing Airy beam generators can only respond to one polarization state of electromagnetic waves and produce the single Airy beam, which immensely limit the serviceability and utilization of the Airy beam generators. Herein, an inspiring strategy of multichannel Airy beam generator based on the multichannel amplitude and phase controlled metasurface is proposed to independently generate the Airy beams for linear polarized waves in 20–24 GHz and orthogonal circular polarized waves in 12–14 GHz and 15–17 GHz. Notably, an appealing paradigm of multichannel beam focusing can be realized by the integrated multichannel Airy beam generator, which possesses strong ability to circumvent the obstacle owing to the self-healing feature of the Airy beam. A proof-of-concept prototype is constructed to verify the feasibility of our methodology, and multitudinous simulations and experiments are in excellent accordance with our theoretical predictions. This novel design of multichannel Airy beam generator will have tremendous application potential in sensing, communication and other multifunctional metadevices. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Rayleigh-Sommerfeld diffraction theory and the diffractive neural network algorithm are used to construct the multiplexing meta-hologram. • Low channel crosstalk of the designed helicity-assisted meta-atom ensures the high fidelity of the reconstructed multiple images. • The multiplexing meta-hologram is proposed to independently and simultaneously reconstruct four images in three amplitude-phase channels and one phase-only channel. • The multiplexing meta-hologram can theoretically achieve perfect holography in sixteen imaging channels by easily rotating, mirroring, and arranging the structures. • The multiplexing meta-hologram is able to realize information display, storage and encryption by encoding all imaging channels. Holography has been continuously spurring tremendous interest of researchers attributed to its unparalleled capability of photographically reconstructing the desired images. Based on the metasurfaces with multiple degrees of freedom, multiplexing meta-holograms are experiencing the research upsurge because of enormous application potential. However, existing multiplexing meta-holograms cannot tailor the amplitude information, and possess limited imaging channels and high channel crosstalk, which hinder the improvement of information capacity and imaging quality of multiplexing meta-holograms. Herein, an innovative multiplexing meta-hologram based on the helicity-assisted meta-atoms is proposed, which can perfectly reconstruct four independent images by altering the working frequency, polarization state and propagation direction of incident waves, and theoretically realize the holography in sixteen different channels by easily rotating, mirroring, and arranging the structures of meta-atoms. Numerous simulations and experiments collectively corroborate the feasibility of our methodology, and the quantitative analyses verify the high fidelity of the reconstructed images, which results from the low crosstalk between the amplitude modulation and phase modulation in different imaging channels. This inspiring strategy of multiplexing meta-hologram with large channel capacity and high imaging quality will have promising application prospects in information display, storage and encryption, and provide an alternative path for the design of multifunctional microwave devices. [ABSTRACT FROM AUTHOR]

Abstract: Graphene was prepared using a modified Hummers’ method. The physico-chemical properties of graphene were characterized by TEM, BET specific surface area, FTIR, Raman and XRD measurements. The effect factors including pH, contact time, temperature and dosage on the adsorption properties of methylene blue onto graphene were investigated. The experimental data of isotherm followed the Langmuir isotherm model better than the Freundlich model. The maximum adsorption capacity obtained from Langmuir isotherm equation at 293K was 153.85mg/g, indicating graphene is a good adsorbent for the adsorption of MB. The kinetic study illustrated that the adsorption of methylene blue onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of methylene blue onto graphene was an endothermic and spontaneous process. [Copyright &y& Elsevier]

Stealth performance plays an increasingly important role in the evaluation of aircraft performance, while achieving excellent stealth performance in multiple frequency bands simultaneously remains a crucial challenge. Herein, a visible transparent wideband microwave absorber with infrared camouflage function is theoretically presented and experimentally demonstrated. The sample is composed of two radar absorption layers (RALs) and an infrared shielding layer (IRSL). In addition, the magnetic resonance model and the ohmic loss model are employed to strengthen the absorption of the designed RALs >90% in a broadband frequency range of 7–23 GHz with a relative bandwidth of 106.7%, and an average visible transmittance of ≈60%. Furthermore, IRSL is achieved by a designable digital frequency selective surface (FSS), which promotes a compatible design between infrared camouflaged emissivity and microwave absorption. These peculiar properties not only verify the feasibility of the proposed strategy for achieving suitable artificially designed IR digital camouflage patterns to meet various thermal camouflage environments, but also have promising application prospects in multispectral stealth. The additional visible light transparent feature makes it useful in compatible camouflage‐stealth facilities when requiring observing and operating in optical windows. [ABSTRACT FROM AUTHOR]

In this article, we propose a method of achieving broadband decoupling between large antenna arrays using magnetic metasurface (MM). To realize broadband isolation performance, the MM consists of four sub‐regions composed periodic arrays of split‐ring resonators (SRRs). The four sub‐regions can achieve negative permeability in sequential frequency ranges, which can together cover the whole X‐band by proper combinations. When the MM is placed between the antenna arrays, the propagation of the coupled electromagnetic waves will be suppressed due to the negative permeability, so the isolation between the antenna arrays will be enhanced. For simplicity, the broadband decoupling performance of MM is verified by using patch antenna elements. Prototypes were fabricated and measured. Both simulated and measured results show that when the distance between the two antenna elements is about half a meter, the isolation can be enhanced by at least 25.0 dB in the whole X‐band, which convincingly verifies our method. This work provides an alternative to enhancing isolation between broadband antenna arrays and may find applications in electromagnetic compatibility of integrated masts, base stations, and so on. [ABSTRACT FROM AUTHOR]

The gaseous or particulate forms of divalent mercury (HgII) significantly impact the spatial distribution of atmospheric mercury concentration and deposition flux (FLX). In the new nested-grid GEOS-Chem model, we try to modify the HgII gas-particle partitioning relationship with synchronous and hourly observations at four sites in China. Observations of gaseous oxidized Hg (GOM), particulate-bound Hg (PBM), and PM 2.5 were used to derive an empirical gas-particle partitioning coefficient as a function of temperature (T) and organic aerosol (OA) concentrations under different relative humidity (RH). Results showed that with increasing RH, the dominant process of HgII gas-particle partitioning changed from physical adsorption to chemical desorption. And the dominant factor of HgII gas-particle partitioning changed from T to OA concentrations. We thus improved the simulated OA concentration field by introducing intermediate-volatility and semi-volatile organic compounds (I/SVOCs) emission inventory into the model framework and refining the volatile distributions of I/SVOCs according to new filed tests in the recent literatures. Finally, normalized mean biases (NMBs) of monthly gaseous element mercury (GEM), GOM, PBM, WFLX were reduced from −33%–29%, 95%–300%, 64%–261%, 117%–122% to −13%–0%, −20%–80%, −31%–50%, −17%–23%. The improved model explains 69%–98% of the observed atmospheric Hg decrease during 2013–2020 and can serve as a useful tool to evaluate the effectiveness of the Minamata Convention on Mercury. [ABSTRACT FROM AUTHOR]

Surface plasmon polaritons (SPPs) have great applications in imaging, sensing, waveguide, and communication. Especially in the trending of electromagnetic (EM) metastructure field, researchers used the phase gradient design to achieve the efficient surface wave propagating performance ranging from GHz to THz. However, due to the intrinsic coupling interference from the current structure design, the phase and amplitude of different polarization are hard to freely manipulate simultaneously, making the design of multifunctional channels SPPs still a challenging project. Here, an anisotropic structure is proposed to realize independent control of both polarization and amplitude along different component of the wavefront. By analyzing the polarization dependent mechanism, the hexagon and half‐hexagon meta‐atom are introduced to the coupler structure to tailor the desired phase gradient along different directions under different polarized EM waves. Then the dispersion of coupler is further coupled with the propagating patch metasurface by optimization algorithm. As a result, the multifunctional SPP is achieved, and the multimode excitation can be generated under both linear and circular polarized incidence. Both simulation and experiment validate the effectiveness and wideband of spoof SPPs excitation performance, verifying that this method reduces the excitation condition of surface wave and improves the multiplexing effect of propagation channel. [ABSTRACT FROM AUTHOR]

Abstract: Graphene oxide has been used as an adsorbent in wastewater treatment. However, the dispersibility in aqueous solution and the biotoxicity to human cells of graphene oxide limits its practical application in environmental protection. In this research, a novel environmental friendly adsorbent, calcium alginate immobilized graphene oxide composites was prepared. The effects of pH, contact time, temperature and dosage on the adsorption properties of methylene blue onto calcium alginate immobilized graphene oxide composites were investigated. The equilibrium adsorption data were described by the Langmuir and Freundlich isotherms. The maximum adsorption capacity obtained from Langmuir isotherm equation was 181.81mg/g. The pseudo-first order, pseudo-second order, and intraparticle diffusion equation were used to evaluate the kinetic data. Thermodynamic analysis of equilibriums indicated that the adsorption reaction of methylene blue onto calcium alginate immobilized graphene oxide composites was exothermic and spontaneous in nature. [Copyright &y& Elsevier]

Abstract: Graphene, a new member of carbon family, has been prepared, characterized and used as adsorbent to remove phenol from aqueous solution. The effect parameters including pH, dosage, contact time, and temperature on the adsorption properties of phenol onto graphene were investigated. The results showed that the maximum adsorption capacity can reach 28.26mg/g at the conditions of initial phenol concentration of 50mg/L, pH 6.3 and 285K. Adsorption data were well described by both Freundlich and Langmuir models. The kinetic study illustrated that the adsorption of phenol onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of phenol onto graphene was endothermic and spontaneous. [Copyright &y& Elsevier]

Abstract: Enteromorpha prolifera was pyrolyzed to prepare activated carbon using chemical activation by zinc chloride. The effect of activation parameters such as activation temperature, weight ratio (Enteromorpha prolifera to ZnCl2), and activation time was investigated. The BET results showed that the surface area and pore volume of activated carbons were achieved as high as 1722m2/g and 1.11cm3/g, respectively, in the optimal activation conditions. Batch adsorption studies were carried out to study the adsorption properties of cationic red X-GRL onto activated carbon by varying the parameters like initial solution pH, contact time, and temperature. The kinetic studies showed that the adsorption data followed a pseudo second-order model. The isotherm analysis indicated that the adsorption data could be represented by the Langmuir isotherm model. The Langmuir monolayer adsorption capacity of cationic red X-GRL was estimated as 263.16mg/g at pH 6.0. [Copyright &y& Elsevier]

We describe a facile synthesis of Mn 3 O 4 nanoplates (NPs)-anchored graphene microspheres (GSs) and their applications as electrode materials for supercapacitors. The use of GSs as substrate significantly improve the electrochemical performance of Mn 3 O 4 , which can be attributed to unique spherical structure of graphene and excellent stability and anti-reunion of Mn 3 O 4 NPs. The success of this synthesis depends on the in situ reduction of Mn cations by carbon from GSs under hydrothermal conditions. The resultant Mn 3 O 4 NPs with an average thickness of 37 nm were uniformly distributed on the surface of GSs. Material characterizations, including XRD, Raman, FTIR and XPS, have been performed to confirm their shape, composition and structure. As a positive material, the as-prepared Mn 3 O 4 NPs/GSs composites exhibited excellent electrochemical property in a three-electrode system. In particular, their specific capacitance reached as high as 317 F g −1 at a scan rate of 10 mV s −1 , and a remarkable stability (about 100% retention of its initial capacitance) was achieve after 4000 galvanostatic charge-discharge cycles at the current density of 2 A g −1 . Therefore, Mn 3 O 4 NPs/GSs can have been used as an electrode material for supercapacitors. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide hollow microspheres (rGO HMS) were encapsulated with gold nanoparticles (AuNPs) by spray drying. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman spectroscopy were used to characterize the AuNP/rGO HMS. When placed on a glassy carbon electrode (GCE), it exhibits excellent electrochemical catalytic properties towards the oxidation of nitrite. The electrocatalytic properties were studied using various electrochemical techniques. Compared to AuNP-decorated graphene sheet based electrodes documented in the literature, the one presented here provides a larger surface area. This enhances the catalytic activity towards nitrite. The electrode, typically operated at a working potential of 0.82 V (vs. SCE), has a linear response in the 5.0 μM to 2.6 mM nitrate concentration range, and a detection limit as low as 0.5 μM (at an S/N ratio of 3). [ABSTRACT FROM AUTHOR]

[Display omitted] • We propose the orthogonality-simplified machine learning framework to design vectorial-holography metasurface. • A structure with orthogonality is designed to independently control x- and y- polarized waves. • Resistors are embedded in meta -atoms to tailor amplitude. • The design of machine learning architecture is simplified based on the physical principle of orthogonality. • The vectorial-holography metasurface is designed by customizing the polarization. Metasurfaces can provide unprecedented degree of freedom in manipulating electromagnetic waves and have been introduced to holography. Aiming to explore the full capability for information presentation, vectorial metasurface holography is sprung up, which exhibits mesmerizing capability in carrying information compared with scalar counterpart. However, the more flexible modulation means the more complex design dimension, which hinders the development of vectorial metasurface holography. In this work, we propose an orthogonal I-shaped structure embedded with resistors to synthesize arbitrary polarization with less crosstalk. Benefiting from the independent control of phase and amplitude on orthogonal base, the orthogonality-simplified machine learning framework is employed to assist vectorial metasurface holography design. As a proof-of-concept, a vectorial metasurface holography carrying multi-polarization information was designed, simulated and measured. All the results exhibit a high degree of consistency, which fully demonstrates the effectiveness of our design. Encouragingly, our method paves a new route to simplify machine learning framework based on physical significance, which can be handily extended to more functional structures. [ABSTRACT FROM AUTHOR]

Abstract: China's air pollution control policies during the 12th Five Year Plan (2011–2015) are characterized by the targets of 10% nitrogen oxides (NO x ) reduction and 8% sulfur dioxide (SO2) reduction from the 2010 levels. In this study, the Community Multi-scale Air Quality (CMAQ) modeling system was used to evaluate the impact of only SO2, only NO x , and joint SO2/NO x control measures on particulate matter pollution, the greatest concern for urban air quality in China. Four emission scenarios were developed for 2015, including a business-as-usual scenario, a reference NO x control scenario based on the governmental plan, an accelerated NO x control technology scenario, and a scenario assuming joint controls of NO x and SO2 based on the governmental plan. Under the planned NO x control measures, the annual mean concentrations of particulate matter less than or equal to 2.5 μm (PM2.5) decline by 1.5–6 μg m−3, i.e. 1.6%–8.5%, in the majority of eastern China. The largest reduction occurs in the middle reach of the Yangtze River. Under accelerated NO x control measures, the annual average PM2.5 concentration reductions (compared with the business-as-usual scenario) in eastern China are 65% higher than the reductions under planned control measures. The unusual increase of PM2.5 concentrations in the North China Plain and the Yangtze River Delta during January after the reductions of NO x emissions was an integrated effect of excessive NO x , the ammonia-rich inorganic aerosol chemistry, and the non-methane volatile organic compounds (NMVOC) sensitive photochemical regime. Under the joint controls of NO x and SO2, the annual mean PM2.5 concentrations decline over 3 μg m−3, i.e. 3.2%–13%, in the majority of eastern China, and some areas in the middle reach of the Yangtze River have reductions as large as 6–8.3 μg m−3, i.e. 5.0%–13%. The average PM2.5 concentration reductions in eastern China are 1.20 μg m−3, 3.14 μg m−3, 3.57 μg m−3, 4.22 μg m−3 in January, May, August, and November, respectively. The corresponding declining rates are 2.3%, 12.2%, 14.3%, and 8.1%, respectively. More stringent policies should be implemented in winter to reduce the heavy pollution periods. The annual average PM2.5 concentration reductions in three major city clusters are comparable with the average reductions of eastern China. Stringent regional control policies are required for the significant improvement of particulate air quality in major city clusters. [Copyright &y& Elsevier]

[Display omitted] • PCDD/F (87.48–94.59%) and NO x (42.74–67.51%) were well simultaneously removed at 160–200 ℃. • The removal efficiencies of PCDD/F were higher than 87% at 160 ℃. • The catalytic reaction rates of PCDD/F were highly correlated to temperature with R2 of 0.97. • The apparent activation energy of PCDD, PCDF and PCDD/F were 11.26 kJ/mol, 17.11 kJ/mol, 14.40 kJ/mol, respectively. One commercial granular catalyst was investigated, including catalysts characteristics, removal efficiencies (RE) and mechanism of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/F) and NO x , kinetics analysis of PCDD/F. The high surface area (96.77 m2/g), the dominative species of V5+ (74.79%), and good redox ability and anatase-TiO 2 provided the advantages on catalysis of PCDD/F. The RE of PCDD/F were high and followed 94.59% for total PCDD/F (95.43% for toxic PCDD/F)＞90.57% (91.74%)＞87.48% (84.98%), with decreasing operating temperature of SCR (200 ℃, 180 ℃ and 160 ℃, respectively), which were closely associated with the decreasing catalytic reaction rate (k). While the RE of NO x was generally low and decreased from 67.51% to 45.03% and 42.74%, respectively. The catalyst better favors the PCDF removal in higher operating temperature (200 ℃, 180 ℃) but PCDD removal in lower temperature (160 ℃). Kinetics analysis revealed the k of most PCDD/Fs generally decreased with the decreasing operating temperature, and the correlation coefficient (R2) with the k of PCDD, PCDF and PCDD/F were 0.91, 0.99 and 0.97, respectively. The apparent activation energy (E a) of PCDD/F was 14.40 kJ/mol, and the E a of PCDD (11.26 kJ/mol) was lower than that of PCDF (17.11 kJ/mol). [ABSTRACT FROM AUTHOR]

Abstract: A new adsorbent manganese oxide coated graphene oxide (MOGO) was synthesized and characterized by TEM, XRD, FTIR, and BET analysis. The effects of different parameters such as pH, adsorbent dose, contact time and temperature were studied to understand the adsorption behavior of the adsorbent under various conditions. Adsorption studies revealed that optimum removal of fluoride occurred in a pH range of 5.5–6.7. The Langmuir isotherm model demonstrated that the maximum fluoride adsorption capacity of MOGO was 11.93mg/g and 8.34 times higher than that of GO. The kinetic adsorption data were analyzed using the pseudo first-order model, the pseudo second-order model and the intra-particle diffusion model. Thermodynamic adsorption results showed that adsorption of fluoride by MOGO was a spontaneous and endothermic process. [Copyright &y& Elsevier]

Abstract: A batch adsorption system was applied to investigate the adsorption of fluoride from aqueous solution by graphene. The adsorption capacities and rates of fluoride onto graphene at different initial pH, contact time, and temperature were evaluated. The experimental results showed that graphene is an excellent fluoride adsorbent with an adsorption capacity of up to 17.65mg/g at initial fluoride concentration of 25mg/L and temperature of 298K. The isotherm analysis indicated that the adsorption data can be well described by Langmuir isotherm model. Thermodynamic studies revealed that the adsorption reaction was a spontaneous and endothermic process. [Copyright &y& Elsevier]

• Ultra-low emission (ULE) retrofit significantly improves the overall Hg removal efficiency of devices. • The improvement of overall Hg removal after ULE retrofit mainly comes from the effect of dust removal devices. • Hg contents of both fly ash and gypsum are significantly lower than 25 mg/kg. • Large amount of Hg embodied in fly ash and gypsum calls for policies to guide the disposal of these wastes. China has applied the ultra-low emission technology in coal-fired power plants to control traditional air pollutants and to reduce Hg emissions synergically. In this study, we applied field experiment, model calculation, and literature review to evaluate the Hg control effect of ultra-low emission technology and the potential cross-media effect comprehensively. The dominant ultra-low emission technology significantly improves the atmospheric Hg removal efficiency from 75% to 87%. Such improvement mainly comes from the effect of dust removal devices. Based on the calculated distribution characteristic of Hg content of wastes, we find out that the improvement of Hg control effect of air pollution control devices significantly increase the Hg content of fly ash, which rises from 0.16 mg/kg to 0.33 mg/kg. However, the Hg content of gypsum decreases from 0.75 mg/kg to 0.51 mg/kg. Whether or not to carry out ultra-low emission retrofits, Hg contents of wastes from coal-fired power plants are overall lower than the limit of 25 mg/kg which is intended to be set as the limit for Hg-containing wastes. However, the embodied more than two hundreds of tons Hg in these wastes still require policies to guide the disposal of these wastes. [ABSTRACT FROM AUTHOR]

The serious fine particle (PM 2.5) pollution in China causes millions of premature deaths. Driven by swift economic growth and stringent control policies, air pollutant emissions in China have changed significantly in the last decade, but the change in the source contribution of PM 2.5 -related health impacts remains unclear. In this study, we develop a multi-pollutant emission inventory in China for 2005–2015, and combine chemical transport modeling, ambient/household exposure evaluation and health impact assessment to quantify the contribution of eight emission sectors to PM 2.5 exposure and associated health risk. From 2005 to 2015, the mortality due to PM 2.5 from ambient air pollution (AAP) decreases from 1.04 (95% confidence interval, 0.84–1.25) million to 0.87 (0.70–1.04) million. The agricultural sector contributes 25% and 32% to ambient PM 2.5 -attributed mortality in 2005 and 2015, respectively, representing the largest contributor during this period. The contribution of power plants drops monotonously from 13% to 6%. The percentage contribution of industrial process drops significantly while the contribution of industrial combustion stays the same level. The overall contribution of industry is still as large as 26% in 2015 in spite of strict control measures. For transportation, despite strict emission standards, its contribution increases remarkably due to the rapid growth of vehicle population. When both ambient and household PM 2.5 exposures are taken into account, the mortality due to integrated population-weighted exposure to PM 2.5 (IPWE) drops from 1.78 (1.46–2.09) million in 2005 to 1.28 (1.05–1.52) million in 2015. Most of the IPWE reduction comes from domestic combustion as a result of urbanization and improved income, whereas this sector remains the largest contributor (58%) to IPWE-related health risk in 2015. Our results suggest that the government should dynamically adjust the air pollution control strategy according to the change in source contributions. Domestic combustion and agriculture should be prioritized considering their predominant contributions to mortality and the lack of effective control policies. More stringent control measures for industry and transportation are necessary since the existing policies have not adequately reduced their health impacts. Electricity production is no longer the top priority of air pollution control policies given its lower health impact compared with that of other sources. • We analyze source contribution to PM 2.5 exposure and related mortality in China. • Domestic combustion and agriculture contribute most but lack control policies. • More stringent control measures are needed for industry and transportation. • Electricity is no longer the top priority of air pollution control policies. [ABSTRACT FROM AUTHOR]