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• H 2 O 2 modification of hydrochar increased surface functional groups on hydrochar. • Modified hydrochar adsorbed NH 4 + better than pristine hydrochar by two times. • NH 4 +adsorption was mainly controlled by cation exchange and electrostatic attraction. • Modified hydrochar can be used as a promising alternative adsorbent for NH 4 + removal. This work investigated adsorption behaviors of NH 4 + onto H 2 O 2 modified paper waste sludge-derived hydrochar (HPSH). Effect of various operational parameters, including modification ratio, solution pH, adsorbent dosage, initial NH 4 + concentration and contact time on NH 4 + adsorption was studied. Besides, the NH 4 + adsorption isotherms, kinetics and thermodynamics at different operational temperatures were systematically investigated. The textural, morphology, crystalline structure and surface chemistry characteristics of hydrochars were analyzed. Specially, NH 4 + adsorption mechanisms controlled by enriched oxygen-containing surface functional groups by treatment of H 2 O 2 onto hydrochars were deeply discussed. The results showed that the optimal treatment ratio between H 2 O 2 and PPSH was 40. Characterization data indicated H 2 O 2 modification increased the oxygen-containing functional groups on the hydrochar surface. The maximum adsorption capacity of HPSH-40 was 7.941 mg/g which was higher that of PPSH about double. NH 4 + adsorption onto hydrochars was well described by the pseudo-second-order model and Langmuir isotherm. The thermodynamic studies showed NH 4 + adsorption onto hydrochars was endothermic in nature. The mechanisms of NH 4 + adsorption onto hydrochars included π-cation interaction, cation exchange, surface complexation and electrostatic attraction which were attributed to the vital role of enriched oxygen-containing surface functional groups on hydrochar's surface. [Display omitted] [ABSTRACT FROM AUTHOR]

A microfluidic paper-based analytical device (μPAD) utilizing gas-diffusion separation and solid-phase reduction was developed for the first time for the determination of both ammonium and nitrate, which are the dominant inorganic nitrogen species in environmental waters. The device consists of 3 filter paper layers accommodating the sample, reagent and detection zones. The reagent zone is separated from the detection zone by a semipermeable hydrophobic membrane and acts as a solid-phase reactor where nitrate is reduced to ammonia by Devarda's alloy microparticles, integrated into a μPAD for the first time. The detection zone incorporates the acid-base indicators bromothymol blue (BTB) or nitrazine yellow (NY) and changes colour in two steps. Initially the colour change is caused by ammonia generated by the reaction of ammonium and sodium hydroxide in the sample zone. This colour change is followed by a subsequent colour change as a result of the ammonia produced by the reduction of nitrate by the Devarda's alloy microparticles. The corresponding reflectance value changes are used for the quantification of the two inorganic nitrogen species in the ranges 6.5–100.0 or 2.1–15.0 mg N L−1 for ammonium and 18.2–100.0 or 4.2–15.0 mg N L−1 for nitrate when BTB or NY are used, respectively. Under optimal conditions the limits of quantification of ammonium and nitrate in the case of BTB were determined as 6.5 and 18.2 mg N L−1, respectively, while the corresponding values in the case of NY were found to be 2.1 and 4.2 mg N L−1. The newly developed μPAD was stable for 62 days when stored in a freezer and 1 day at ambient temperature. It was validated with a certified reference material and successfully applied to the determination of ammonium and nitrate in spiked environmental water samples and soil extracts. [Display omitted] • A microfluidic paper-based analytical device (μPAD) for inorganic N is proposed. • NH 4 + and NO 3 − are determined as NH 3 ; NO 3 − is reduced to NH 3 by Devarda's alloy. • NH 3 is separated across a Teflon membrane by a gas-diffusion approach. • Detection is based on colour change of bromothymol blue or nitrazine yellow. • The μPAD is validated with a certified reference material and spiked water samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low-cost and environmental-friendly fabrication of the PAD using the superhydrophobic eggshell. • The superhydrophobic eggshell barrier enables excellent water and chemical resistance. • Successful application for the colorimetric determination of ammonium cations in water samples. This work demonstrates the first application of the superhydrophobic eggshell as an environmental-friendly material for fabricating the hydrophobic barrier of a paper-based analytical device (PAD). The eggshell surface was modified by mixing the pulverized chicken eggshell biowaste with stearic acid and a polystyrene binder to accomplish superhydrophobicity. The PAD (10 × 10 mm2) is comprised of the circular-shaped hydrophilic reservoir (Ø 5 mm). The liquid barrier was fabricated by painting both the topside and the underside of the filter paper with the dispersed superhydrophobic eggshell solution. The SEM images revealed that the microsized superhydrophobic eggshell particles absorbed onto the porous surface of the cellulose fibril. A coated surface with a water contact angle of 155.39° ± 1.02° (n = 10) on the paper substrate was achieved, and this indicated superhydrophobicity. The eggshell barrier enabled excellent water and chemical resistance. The fabricated PAD was applied for the colorimetric determination of ammonium cations (NH 4 +), based on the modified Berthelot reaction. Samples and chromogenic solutions were aliquoted onto the hydrophilic reservoir, with subsequent capture of the optical image of the stable, green-colored product by a smart phone under a light-controlled studio. The green color intensities were evaluated by ImageJ™ and plotted against the standard NH 4 + concentrations. A wide linear calibration range 5.0 to 100 mg N/L was achieved with good linearity (r2 > 0.99). The PAD confirmed satisfied analytical recovery (Mean ± SD: 100.6 % ± 0.97, n = 11 samples) and high precision (RSD = 0.85 %: 10-PAD replicate measurements of 1.0 mg N/L). The limit of detection (3 SD of blank/slope) of 1.05 mg N/L was found sensitive enough to monitor the NH 4 + contents in freshwater. The results, determined by the developed PAD and ion chromatography, showed no significant difference under the statistical paired t -test at 95 % confidence (t stat = -1.80, t cri = 2.57, n = 6 samples). [ABSTRACT FROM AUTHOR]

Most of the on-site approaches for inferring of the post-mortem interval are still based on observative data from the direct body inspection, whereas, objective and quantitative analyses, such as potassium in the vitreous humor, are require laboratory instrumentation and skilled personnel. The present paper presents a simple and low cost analytical method suitable for use at the crime scene for inferring the time since death. The method uses a microfluidic paper-based device (μPAD) for the determination of ammonium in the vitreous humor (VH) based on the selective interaction between the ammonium and the Nessler's reagent. The color change was measured in terms of "RGB distance" by using a simple and free smartphone application. The optimized device showed a limit of detection of 0.4 mmol L−1, with between days precision less than 9.3% expressed as relative standard deviation, and accuracy between days from 94.5% to 104.5%. The selectivity of the Nessler's reaction was tested towards the main vitreous humor compounds, and no significant interferences were found. This paper-based analytical device was successfully used for the determination of ammonium ion in VH samples from forensic autopsies. The results obtained with the proposed method, although for a limited number of cases (n = 25), showed a close correlation with the data obtained with an instrumental analysis based on capillary electrophoresis. Moreover, in order to make the evaluation of results as simple as possible, a direct correlation between the color intensity, expressed as RGB distance, and the post-mortem interval was studied and a significant correlation was found (R2 > 0.78). In conclusion, the present preliminary study showes that the proposed device could be an additional tool to the traditional methods for a more accurate, although still presumptive, estimation of the time of death directly at the crime scene. Image 1 • A simple and low cost analytical method suitable for use at the crime scene for inferring the time since death is presented. • The device uses the microfluidic paper-based technology and the selectivity of the Nessler's reagent towards ammonium ion. • A concordance between the results obtained with the proposed procedure and those using CE-UV is proved. • The proposed procedure showed significant advantages for thanatochemical analysis at the crime scene. [ABSTRACT FROM AUTHOR]

[Display omitted] • Design of the first bi-parametric µPAD for ammonium and urea determination in human saliva. • Enzymatic reaction combined with gas diffusion membrane prior to colorimetric reaction. • Direct saliva introduction, no sample pretreatment required. • Successfully application to saliva samples with different collection procedures. In this work, two microfluidic paper-based analytical devices (μPADs) were developed for the quantification of urea and NH x in human saliva to aid in the diagnosis/monitoring of chronic kidney disease (CKD). The NH x determination was based on the conversion of ammonium to ammonia, followed by its diffusion through a hydrophobic membrane and then the color change of bromothymol blue (BTB) indicator. In the urea determination, prior to the ammonium conversion and BTB color change, the enzymatic conversion of urea into ammonium was produced, using urease. Several optimization studies were carried out to attain a quantification range of 0.10–5.0 mM with 0.032 mM limit of detection for the NH x μPAD, and a determination range of 0.16–5.0 mM with 0.049 mM limit of detection for the urea μPAD. The method accuracy was assessed, and the measurements obtained with NH x μPAD were compared with the ones obtained from an ammonia ion selective electrode; while the measurements of the urea μPAD were compared with the ones obtained from a commercially available kit. There were no statistically significant differences between methods, proving that both NH x and urea μPAD were effective on-hand tools for CKD monitoring in saliva. To evaluate their functionality as point-of-care devices, stability studies were also performed and revealed that both NH x and urea μPAD were stable when stored in a vacuum for 2 and 1 month, respectively. After the sample introduction, the NH x μPAD could be scanned within the first 2 h and the urea μPAD within 1 h. [ABSTRACT FROM AUTHOR]

Abstract: A hybrid nanopaper consisting of carbon nanofibre (CNF) and/or clay, polyhedral oligomeric silsesquioxane (POSS), ammonium polyphosphate (APP), has been fabricated through the papermaking process. The as-prepared hybrid nanopaper was then incorporated onto the surface of glass fibre (GF) reinforced polymer matrix composites through injection moulding. The morphologies of hybrid nanopapers with and without the polymer resin were characterized with scanning electron microscopy (SEM). The polymer resin penetrated the entire nanopaper under a high-pressure compressed air system. The thermal decomposition behaviour of hybrid nanopapers infused with resin was studied with real-time thermogravimetric analysis/Fourier transform infrared spectrometry (TGA/FTIR). The test results indicate that the addition of clay in the hybrid paper increased the char residues of the nanocomposites. The fire retardant performance of composite laminates incorporating hybrid nanopaper was evaluated by cone calorimeter testing using a radiant heat flux of 50kW/m2. The cone test results indicated that the peak heat release rate (PHRR) decreased dramatically in the case of laminate composites incorporating CNF/clay/APP hybrid paper. However, the extent of reduction of PHRR of the composite laminates incorporated with CNF/POSS/APP hybrid paper was lower. The formation of compact char materials was observed on the surface of the residues and analyzed by SEM and X-ray photoelectron spectroscopy (XPS). The flame retardant mechanisms of hybrid nanopapers in composite laminates are discussed. [Copyright &y& Elsevier]

Al-containing CaO–SiO2–H2O phases were prepared by hydrothermal treatment of mixtures of paper sludge ash (PSA) with various silica and calcia sources and their properties were determined with particular reference to the simultaneous uptake of ammonium and phosphate ions, which are implicated in the eutrophication of lakes and ponds. After examination of various silica and calcia sources, Ca(OH)2 and SiO2 sol were selected as the most appropriate starting materials. Dry milling was found to be superior to wet milling in avoiding contamination from the milling media during mixing. Nine samples with three different Ca/Si ratios and Al2O3 contents were prepared with various mass ratios of Ca(OH)2, PSA and SiO2. The chemical compositions of the hydrothermal products of these mixtures moved towards the tieline of CaSiO3-PSA, with respect to the starting compositions. The major phase formed in all samples was poorly crystalline C–S–H(I), with hydroxysodalite also formed in the Al-containing mixtures. All the products showed a capacity for the simultaneous uptake of ammonium and phosphate ions. The saturated sorption capacities calculated from the Langmuir equation ranged from 0. 9 to 2. 4mmol/g for the ammonium ion and from 3. 3 to 5. 2mmol/g for the phosphate ion. Since the sorption capacities for both ions increased with increasing Ca contents of the product, substitution of Ca2+ for NH4 + and the formation of calcium phosphate phases such as apatite and brushite by precipitation are thought to be the main sorption mechanisms. [Copyright &y& Elsevier]

The production of hydrogen via photocatalytic water splitting is one of the most promising technologies for obtaining chemical energy from direct solar energy while maintaining the least possible waste and pollutants. In this paper, we obtain the kinetic parameters necessary for the design of a photoreactor for photolysis and photocatalysis of ammonium sulfite solution. For the case of photolysis, we obtain the kinetics for the effect of changing the pH on the produced amount of hydrogen. For the case of photocatalysis, the intrinsic kinetic parameters of photocatalysis of water splitting reaction of ammonium sulfite and water in the presence of cadmium sulfide as a catalyst under solar radiation was inspected by developing MATLAB codes that can predict the kinetics based on the results of experimental work done. The resulted kinetics are compared to experimental work already done. These obtained kinetic parameters provide guidance for the design or scale-up of a solar photoreactor. [ABSTRACT FROM AUTHOR]

In this paper, a new type of highly efficient intumescent flame-retardant low-density polyethylene composite was prepared using two key technologies, namely, microencapsulation encapsulation technology and novel carbon formation technology. Precisely, β-cyclodextrin encapsulated modified ammonium polyphosphate@melamine formaldehyde resin (β-CDMCAPP@MF) was prepared by using Si-IFR synergistic flame retardant effect combined with the gel-solution method, and then flame retardant low-density polyethylene (LDPE) was prepared by compounding with tris-(2-hydroxyethyl) isocyanate (THEIC). The results showed that β-CDMCAPP@MF was modified with MF, β-CD, and silica coating. This modification resulted in excellent hydrophobicity and good compatibility with LDPE. The addition of IFR containing β-CDMCAPP@MF significantly improved the flame retardancy of the LDPE composites. Specifically, when 30 wt% of β-CDMCAPP@MF was added, the ultimate oxygen index of the composites reached 24.7 %, and V-0 grade and the tensile strength went 11.41 MPa. Compared with IFR/LDPE with the same proportion of MF@MCAPP and β-CD@MCAPP, the ultimate oxygen indices were increased by 9.72 % and 12.15 %, respectively. The introduction of THEIC into the flame retardant system resulted in a LOI value of 36.5 % and an FRI value of 2.523, which is 32.33 % higher than that of the composites containing 30 wt% of the flame retardant system (without THEIC). Cone calorimetry test results showed that introducing β-CDMCAPP@MF and THEIC significantly improved the smoke emission. [Display omitted] [ABSTRACT FROM AUTHOR]

• A new modification of RbVOPO 4 has been synthesized for the first time through mild ion exchange using NH 4 VOPO 4 as a precursor. • The crystal structure of the RbVOPO 4 was refined using the Rietveld method. The model has been verified by selected area electron diffraction (SAED), high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and infrared spectroscopy. • BVSE and DFT calculations have been performed: the RbVOPO 4 is featured by a one-dimensional diffusion network (E a = 0.2 eV). • Electrochemical measurements results are in agreement with theoretical findings: KTiOPO 4 -structured RbVOPO 4 demonstrates reversible cycling of alkali metal cations. In this paper, we report on a new polymorph of rubidium vanadium oxophosphate (α-RbVOPO 4) adopting a KTiOPO 4 -type structure, which was stabilized through an ion-exchange reaction between a hydrothermally prepared NH 4 VOPO 4 precursor and Rb 2 CO 3 ·1.5H 2 O. The crystal structure of α-RbVOPO 4 was refined based on X-ray powder diffraction data and verified by infrared spectroscopy, selected area electron diffraction, and high-resolution scanning transmission electron microscopy. The material was examined as a host for reversible (de)insertion of Rb+ ions using bond valence force field and density functional theory calculations disclosing a one-dimensional diffusion network with an activation barrier of ∼0.2 eV. The electrochemical activity of RbVOPO 4 was studied experimentally in two-electrode cells with Li, Na, and K metal counter electrodes. Electronic structure calculations confirmed vanadium redox during Rb+ (de)insertion. The α-RbVOPO 4 phase was compared with the known RbVOPO 4 polymorphic modification, β-RbVOPO 4 , demonstrating no ionic mobility. The crystal chemistry of all known compounds in the Rb-V-P-O system is reviewed. This work supplements the existing toolkit on synthesizing the KTiOPO 4 -structured electrode materials for metal-ion batteries and discusses their crystal structure features. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • We used AG, a bioactive compound extracted from Licorice root, as surfactant. • We have shown the AG ability to self-assemble in homogeneous and stable vesicular structures. • AG niosomes obtained, showed an important antinflammatory activity. • AG niosomes were investigate as carrier of other compounds such as curcumin. In this paper, the surfactant properties of Ammonium Glycyrrhizate, a bioactive compound present in Licorice root were studied. Considering the ability of this bioactive molecule to form micelles, we investigated for the first time the self-assemble of Ammonium Glycyrrhizate in vesicle structures. The organization of Ammonium Glycyrrhizate in vesicles allows to increase its bioavailability and, so, efficacy but also to use them as carrier of other drugs for potential combination therapy. Niosomes made up of Ammonium Glycyrrhizate were prepared using thin layer evaporation technique without the use of additional excipients and characterized in term of size, polydispersion index, Zeta potential and colloidal stability. Moreover, the performance of these innovative vesicles as carriers of hydrophilic drug (Fluorescein sodium) or a lipophilic molecule (Curcumin), was evaluated. Nanocarriers showed nanometric sizes, hexagonal shape, high colloidal stability and ability to encapsulate both hydrophilic and hydrophobic molecules. These vesicles did not showed cytotoxicity nor antimicrobial activityMoreover, it was found that these niosomes enhanced skin permeation and diffusion in several media and an important ability to interact with mucin. Considering its antinflammatory nature, in vitro inhibition of albumin denaturation assay was also carried out to test if the drug maintains these properties also when organized in colloidal structures. The obtained results highlighted an important antinflammatory activity suggesting the potential role of these nanodevices alone or loaded with other therapeutic molecules for the treatment of inflammatory-based diseases. [ABSTRACT FROM AUTHOR]

The increasing deterioration of freshwater bodies has prompted the development of legislation for priority substances (PSs) and contaminants of emerging concern (CECs). In parallel, advanced treatment processes have been investigated to remove these contaminants from wastewaters and the assessment of the potential impacts of some of these processes has been performed throughout their life cycle. In this paper, a comparative life cycle assessment of the solar heterogeneous photocatalysis treatment of secondary urban wastewater using a carbon-based composite (consisting of graphene oxide and titanium dioxide, GO-TiO 2) or commercially available titanium dioxide material (TiO 2 –P25) as photocatalysts is conducted. It was found that the solar/GO-TiO 2 treatment, which implements GO-TiO 2 synthesized by the liquid phase deposition method, has higher potential impacts than the solar/TiO 2 option in all categories assessed under the present conditions due to the high potential impacts of the GO-TiO 2 synthesis method (i.e. , using ammonium hexafluorotitanate and boric acid as precursors to obtain TiO 2 in the composite). A composite prepared with TiO 2 –P25 and GO via a mechanical process seems to be a better solution to reduce all potential environmental impacts, but the resulting photocatalytic activity should also be considered before reaching a decision. [Display omitted] • Using GO-TiO 2 instead of TiO 2 –P25 increases all potential environmental impacts. • (NH 4) 2 TiF 6 and H 3 BO 3 use in GO-TiO 2 synthesis is highly impactful. • Alternatives for the source of TiO 2 in the GO-TiO 2 composite are needed. • Synthesizing GO-TiO 2 by other methods may be a more interesting option. • The impact of GO synthesis is not relevant in comparison to TiO 2 addition to the composite. [ABSTRACT FROM AUTHOR]

The transport of live fish is a delicate aquaculture operation that is carried out to distribute the fry or juveniles produced in the laboratories, to the culture farms. In the present work, survival after transport, survival during the subsequent 8 days (8-D PTS), and blood glucose as an indicator of stress, were determined in a simulated transport of Oreochromis niloticus tilapia fry of two sizes (1.2 ± 0.3 g and 2.4 ± 0.3 g), to find the best transport conditions. A total of 63 treatments per size, were tested combining three transport times (4, 8, and 24 h), three densities (54, 66, and 80 g/L), three temperatures (20, 22, and 24 °C), three salinities (3, 6, and 9 ‰) and three concentrations of dissolved oxygen (DO) (10, 15, and 20 mg/L). The tests were carried out in 2 L plastic bags, containing 0.5 L of water and an atmosphere above of pure oxygen. In general terms, the tested conditions of temperature, salinity, DO and density did not produce fry mortality at the end of transport in any of the treatments. However, the 8-D PTS gradually declined during the first 4–5 days and stabilized up to day 8 of experimentation. Survival of small fry of 1.2 ± 0.3 g was significantly (P < 0.05) lower (77.7 ± 10.4%) compared to that (94.2 ± 6.1%) obtained in 2.4 ± 0.3 g fry. The expected 8-D PTS was plotted as response surfaces to show 8-D survival as a function of density, transport time, and fry weight. Mortality during the 8-day post-transport period was the result of the combined effect of temperature and handling of the fry, rather than due to a lack of oxygen or ammonia concentrations since both variables were at tolerable levels for the species. With these results, it is concluded that the best transport conditions, under the evaluated scenarios, are obtained with fry of 2.4 ± 0.3 g transported at a density of 80 g/L for up to 24 h, at 24 °C and 3 ‰. • Plastic bag system is a good alternative for transport of tilapia fry. • Immediate survival of 1.2 and 2.4 g fry was 99.4% at 80 g/L in 24 h transport. • 8-day post-transport survival was 97.8 and 81% in 2.4 and 1.2 g fry respectively. • Smaller fry are more affected by low temperature, handling and possibly CO 2 toxicity. • Best transport conditions: 2.4 fry, 80 g/L, 24 °C, 3 psu, O 2 supersaturation, 24 h. [ABSTRACT FROM AUTHOR]

From November 2012 to July 2013, a sampling campaign was completed for comprehensive characterization of PM 2.5 over four key emission regions in China: Beijing-Tianjin-Hebei (BTH), Yangzi River Delta (YRD), Pearl River Delta (PRD), and Sichuan Basin (SB). A multi-method approach, adopting different analytical and receptor modeling methods, was employed to determine the relative abundances of region-specific air pollution constituents and contributions of emission sources. This paper is focused on organic molecular marker based source apportionment using chemical mass balance (CMB) receptor modeling. Analyses of the organic molecular markers revealed that vehicle emission, coal combustion, biomass burning, meat cooking and natural gas combustion were the major contributors to organic carbon (OC) in PM 2.5 . The vehicle emission dominated the sources contributing to OC in spring at four sampling sites. During wintertime, the coal combustion had highest contribution to OC at BTH site, while the major source contributing to OC at YRD and PRD sites was vehicle emission. In addition, the relative contributions of different emission sources to PM 2.5 mass at a specific location site and in a specific season revealed seasonal and spatial variations across all four sampling locations. The largest contributor to PM 2.5 mass was secondary sulfate (14–17%) in winter at the four sites. The vehicle emission was found to be the major source (14–21%) for PM 2.5 mass at PRD site. The secondary ammonium has minor variation (4–5%) across the sites, confirming the influences of regional emission sources on these sites. The distinct patterns of seasonal and spatial variations of source apportionment observed in this study were consistent with the findings in our previous paper based upon water-soluble ions and carbonaceous fractions. This makes it essential for the local government to make season- and region-specific mitigation strategies for abating PM 2.5 pollution in China. [ABSTRACT FROM AUTHOR]

Portable smartphone platform offers a new strategy for on-site and visual quantitative detection of ammonium nitrogen in soil and wastewater samples. [Display omitted] • OPA/K 2 SO 3 /R-QDs and OPA/K 2 SO 3 based sensor have been respectively used for determination of low and high concentration range of NH 4 + via two response modes. • The color responses toward the NH 4 + concentrations have been systematically studied. • The proposed strategy can realize visual quantitative detection of NH 4 + in real samples. • Portable smartphone platform brings great convenience for on-site detection of NH 4 +. Ammonium (NH 4 +) is crucial for plant growth as well as various industrial processes, the accurate and field measurement of the NH 4 + level is of great significance for agricultural precision fertilization and water quality monitoring, but excessive amounts of ammonium can lead to eutrophication of aqueous environments. Herein, the ability of the proposed probe solution and test paper to colorimetric change towards high-concentration NH 4 + and ratiometric fluorescence response to low-concentration NH 4 + has been developed for visual detection of ammonium in real samples. Specifically, high concentration of NH 4 + (0.5–7 mM) could interact with the o-phthalaldehyde (OPA) in presence of K 2 SO 3 , resulting in the colorimetric transition from colorless to wine-red with increasing the NH 4 + concentration. Subsequently, the addition of the red-emitting CdTe QDs (R-QDs) constructed the OPA/K 2 SO 3 /R-QDs ratiometric fluorescent probes for low-concentration NH 4 + (less than 1 mM) sensing with a limit of detection (LOD) down to 18 nM, accompanied by a distinct fluorescence color shift from red to blue under UV light. Furthermore, the visualization detection integrated with smartphone was converted to data information (RGB value) through a Color Recognizer APP and successfully used for visual quantitative identification of NH 4 +. Actually, the proposed probe solution and test paper have been applied to the determination of NH 4 + in soil extracts and wastewater samples. Compared with the standard methods, this established strategy can supply stable and reliable detection results, and allow fast sensing at room temperature, exhibiting great application potential for visual on-site detection of NH 4 + at different concentration ranges in environmental samples. [ABSTRACT FROM AUTHOR]

In this study, dry deposition samples were collected with both an aerodynamically smooth water surface (WSS) and a knife-edge surrogate surface (KSS) in Potsdam, NY, Solomons, MD, and at a farm in upstate NY intermittently between March 2000 and August 2001. The WSS and the citric acid-coated paper filter on the KSS were used to measure total ammonium deposition (NH3 and p-NH4+), while a greased Mylar disk on the KSS was used to measure particulate NH4+ (p-NH4+) deposition. An annular denuder system (ADS) was used to measure NH3 gas phase and particulate NH4+ concentrations. In side-by-side experiments with two WSSs, no statistical difference was found between simultaneously measured total ammonium deposition at any of the sites. Average total NH3 fluxes measured with the WSS in Potsdam, Solomons, and at the farm were 3.1, 2.1, and 310 mg NH4+ m−2 day−1, respectively. Similarly gaseous NH3 fluxes measured with the citric acid-coated paper on the KSS were 3.6, 2.1, and 500 mg NH4+m−2 day−1, respectively. The p-NH4+ fluxes to the KSS-greased strip were negligible at all three locations. Fluxes measured by the citric acid paper filters were slightly greater than those measured with the WSS suggesting that the acidic dry surfaces had a higher affinity for ammonia than the water in the WSS.The average gas-phase ammonia concentrations in Potsdam, Solomons, MD and at the farm were 0.60×10−3, 2.1×10−3, and 0.25 mg NH4+ m−3, respectively. The average ammonium concentrations were 0.50×10−3, 1.2×10−3, and 14×10−3 mg NH4+ m−3, respectively. [Copyright &y& Elsevier]

[Display omitted] • Microwave drying technology for ammonium polyvanadate (APV) was studied. • The kinetics of microwave drying was studied with experimental data fitting. • Page model was robust on describing the microwave drying process of APV. High-quality vanadium pentoxide powder is an important product of the vanadium industry and was usually prepared from ammonium polyvanadate (APV) using a roasting process combined with a drying pretreatment. Conventional hot air drying is usually used for the drying of APV, the heat transfer of which is from outside to inside thus limited the efficiency of the drying pretreatment. In the present paper, microwave heating was applied as an alternative heating method for the drying of APV because of its advantages including selective heating, high heating efficiency, low energy consumption, and green environmental protection. An experimental comparison between hot air drying and microwave drying is provided, and the results show that microwave drying is more energy-saving and faster. The drying characteristics of APV under the irradiation of microwave energy were investigated. The influences of factors including microwave power, material quality, and initial moisture content on microwave drying were studied. The results show that the microwave power, initial moisture content, and initial mass are positively proportional to the microwave drying efficiency of APV. Additionally, the Page model was robust in describing the kinetics of microwave drying and hot air drying of APV. This study provides fundamental knowledge on the microwave drying process and provides the trial for the industrial applications of microwave heating on the preparation of V 2 O 5. [ABSTRACT FROM AUTHOR]

This paper describes a high pressure combustion mechanism of aqueous urea ammonium nitrate (UAN) monofuel. Simulation results were validated by comparison to experiments at pressures of 1–25 MPa and residence times of up to 450 s using a PFR model. Results showed agreement for nitrogen-based species above 15 MPa. For carbon-based species close agreement between experiments and simulations was observed at all pressures. In several conditions, experimental trends were successfully reproduced in the simulation results. Increased pressure and residence time were both found to have a positive effect on pollutant reduction. However, the pressure effect was found to be dominant. A sensitivity analysis was used to identify potential pressure dependent rate limiting reactions during combustion. Different reaction pathways were prominent at 5 and 25 MPa in agreement with the experimental trends. This paper supports the importance of carrying UAN combustion at high pressure to minimize pollutants emission, thereby achieving an environmentally friendly process. [ABSTRACT FROM AUTHOR]

A perovskite sensitized solar cell (PSSC) comprising ethyl ammonium tri-lead iodide (CH 3 CH 2 NH 3 PbI 3 ) and solid polymer electrolyte have been successfully fabricated and reported in this paper. Perovskite was synthesized by direct deposition of equimolar CH 3 CH 2 NH 3 I and PbI 2 in dimethylformamide (DMF) solution. It was further characterized using various experimental tools like XRD, UV–visible, SEM and EDAX. The fabricated PSSC showed a short circuit current density (J sc ) = 1.16 mA/cm 2 , open circuit voltage (V oc ) = 0.70 V, fill factor (FF) = 0.67 and efficiency (ɳ) = 0.75% at one sun condition. Comparative data between PSSC and dye sensitized solar cell (DSSC) are also discussed in this paper. [ABSTRACT FROM AUTHOR]

• TAN recovery via BES as a low-energy intensive alternative to conventional systems. • The TAN recovery rate highly depends on the current density produced. • Challenges for scale-up: nature/quantity of carbon source and NH 4 + concentration. • Describing fundamentals of BES TAN recovery: stripping, absorption or precipitation. Due to the anticipated rise in demand for ammonia, the search for viable methods for its recovery has intensified in recent years, as traditional ammonia production is a high energy intensive process. Bioelectrochemical systems (BESs) offer an alternative solution for ammonia recovery since they have shown lower energy demand (in terms of kJ g−1N recovered) at lab-scale than other methodologies. In BESs, the bioelectrochemically generated current drives the transport of NH 4 + from the wastewater to a concentration chamber through a cation exchange membrane before its subsequent recovery. This paper describes the fundamentals and opportunities for bioelectrochemical ammonia recovery (either by stripping, absorption, or precipitation) in different BES devices such as microbial fuel cells, microbial electrolysis cells, microbial desalination cells and bioelectroconcentration cells and compares the performance of all the reported experimental works so far. Moreover, the most critical challenges (low current density, nature and quantity of the carbon source, inlet ammonium concentration, use of membranes, energy yield and recovery efficiency) have been detailed and discussed in view of better understanding the current bottlenecks for its scale-up and, thus, for its prompt industrial adoption. [ABSTRACT FROM AUTHOR]

• Isophorone diisocyanate based Polyurethane Flexible Foam; • Ammonium polyphosphate-melamine fire retardant system; • Thermal Degradation mechanism by TGA-FTIR; • Toxicity studied by Smoke Density Chamber-FTIR coupling; • Synergetic effect for the combination of both flame retardants Polyurethane (PUR) foams can lead to fatal fires in the presence of an ignition and oxygen source. Obviously, the problem is not the mere loss of PUR foams properties but essentially, the smoke and toxic gases which are the main factors responsible for fire hazards. This paper reports on the main approaches taken to improve the smoke evolution and toxicity of isophorone diisocyanate (IPDI) based PUR foams which are the incorporation of ammonium polyphosphate (APP), melamine (M) and its combinations as additive flame retardants (FRs). In order to better understand the fire behavior, the influence of incorporated FR on the thermal degradation mechanism was also analyzed by means of thermogravimetry coupled to infrared spectroscopy (TGA-FTIR). In addition, foams were characterized in terms of smoke evolution and toxicity of released gases both asphyxiant and irritant using a smoke density chamber coupled to infrared spectroscopy (NBS-FTIR). Data showed that the mixture of APP and M in different amounts reduced the smoke generation and the concentration of harmful gases, underlying a synergetic effect for the combination of both flame-retardants. [Display omitted] [ABSTRACT FROM AUTHOR]

• Sol-gel synthesis method allows efficient doping of TiO 2. • Doped Fe/N/S-TiO 2 is active under visible light irradiation. • Degradation rates by Fe/N/S-TiO 2 are one order of magnitude higher than TiO 2 P25. • Complete degradation of 4-chlorophenol under visible light attained in 180 min. Halogenated aromatic compounds are toxic and carcinogenic. This is the case of 4-chlorophenol (4-CP), a priority pollutant found in large amounts in industrial wastewater effluents from pharmaceutical, dye, pulp and paper industries. Long term exposure to 4-CP even at low-concentration is associated to endocrine disruption. Photocatalysis is a promising advanced oxidation process that attains complete degradation of organic pollutants. The use of UV lamps undermines actual photocatalysis application due to the electrical energy requirements. In this frame, the development of visible light photoactive catalysts can overcome these challenges allowing the implementation using affordable light sources like light emitting diodes (LEDs) or natural sunlight. This work is to present the synthesis and use of an alternative photocatalyst that provided eight-fold increase on 4-CP degradation in comparison to commercial TiO 2 Degussa P-25. Almost complete removal (99.20%) was achieved with synthesized Fe/N/S-doped TiO 2 at 1.0 g L−1 of photocatalyst dose and pH 7.0 for treating 10 ppm of 4-CP.The first-order rate constant, k LH , and Langmuir adsorption constant, K LH , were calculated with values of 0.429 min−1 and 2.326 ppm−1, respectively. The Fe/N/S-TiO 2. photocatalysts showed an excellent stability maintaining their performance during four cycles of recovery/reuse. [ABSTRACT FROM AUTHOR]

Abstract Partial nitrification was developed in this study for the sidestream treatment of high ammonium strength digested sludge supernatant in an integrated fixed film activated sludge (IFAS) reactor operating under sequencing batch mode. This paper elucidated the impacts of feed water characteristics on microbial population dynamics and kinetics in a partial nitrification reactor treating ammonium rich digested sludge thickening lagoon supernatant. It was observed that increased ammonium concentration (100–800 mg-N/L) in the reactor feed led to the enhanced specific ammonium conversion (4.6–12.6 mg-N/g biomass) and nitrite accumulation (0–11.6 mg-N/g biomass) rates, but a reduced microbial community diversity. The increased raw supernatant percentage reduced specific ammonium conversion (6.6 mg-N/g biomass) and nitrite accumulation rates (5.2 mg-N/g biomass) and led to an increased microbial community diversity. Different genera have different tolerances towards the NH 4 +-N concentration and raw supernatant percentage. Microbial community structures varied significantly in suspended flocs and in the attached biofilm. The kinetics analysis revealed that flocs in the IFAS system played a major role in carrying out the partial nitrification processes. Graphical abstract Image 1 Highlights • Nitritation was achieved when the NH 4 +-N concentration in the feed was ≥ 400 mg/L. • High NH 4 +-N concentration in the feed decreased the microbial community diversity. • High raw supernatant % in the feed increased the microbial community diversity. • The NH 4 +-N conversion rate was positively related to the abundance of NH 3 oxidizer. • The suspended flocs played a major role in partial nitrification. [ABSTRACT FROM AUTHOR]

Highlights • A novel process for preparing ATM solution using BMED has been developed. • The effects of various factors on the BMED process have been investigated. • The experimental conditions of BMED process have been optimized. • The consumption of nitric acid can be largely decreased during the ATM preparation. Abstract The disadvantage of the traditional ammonium tetramolybdate (ATM) production process is a large consumption of nitric acid. Therefore a novel process for the generation of ammonium isopolymolybdate solution from ammonium molybdate solution using bipolar membrane electrodialysis (BMED) was developed and the batch experiment was carried out in this paper. The BMED process was studied to optimize various parameters such as initial base solution, final electrolytic pH value of salt solution, current density, initial NH 4 HCO 3 concentration of base solution and Mo concentration in feed solution. The average current efficiency was 82%, the power consumption was 0.058 kWh/mol NH 4 + or 0.887 kWh/mol Mo, and the recovery rate of Mo reached 99.4% under the optimal conditions of a current density of 500 A/m2, an initial Mo concentration of 173 g/L in the salt compartment, an initial NH 4 HCO 3 concentration 2.0 mol/L in the base compartment, an initial (NH 4) 2 CO 3 concentration of 1.0 mol/L in the electrode solution and 32 ± 0.5 °C and a final solution pH of 4.0 in the salt compartment. [ABSTRACT FROM AUTHOR]

Abstract The recovery of polyoxovanadate acid compounds has got increasing attention because of both sustainable necessities and material applications. In this paper, we proposed a recovery strategy of ammonium substituted polyoxovanadate acid compounds (ASPOVC) by solvent extraction from leaching/aqueous solution. It is noted that the state of the compound (solid or liquid) is possibly controllable by the type of amines (branched or linear amine chains), enlarging application fields of these compounds. Subsequently, the compounds were characterized by comprehensive techniques, from which the molecular structures with hydrogen bonds were described. The solubility parameters were calculated, and solid ASPOVC was the biggest among the four compounds, explaining formation reasons of different states. The amine extractants performed well-efficiency (more than 98.5%) for reutilization. This approach is believed to be promised for a sustainable recovery for high-value vanadium materials from waste water. Graphical abstract Image Highlights • A recovery strategy of ASPOVC was developed by solvent extraction. • The state of the compound was controllable by the type of primary amine. • The hydrogen bond extraction mechanism was verified by NMR and FTIR. • The solubility parameters were calculated, of which solid state compound was the biggest. [ABSTRACT FROM AUTHOR]

Abstract Due to acute ammonium toxicity, it is always desirable to find a cheaper and abundant electro-catalyst other than platinum, iridium oxide, boron diamond etc with a high selectivity and negligible de-activation for its oxidation. Also ammonium is not known for electricity generation except biological nitrification process. So this paper elucidates the studies of compost as a novel electro-catalyst in a ammonium fuel cell configuration. These studies are done by varying type of electrodes & compost as well as ammonium concentration. Bi-polar cyclic voltammetry, electrochemical impedance spectroscopy, temperature dependence, cyclic stability and chrono-amperometry techniques are used to study compost. Cow dung based compost is found to show the best electro-catalytic activity. IV measurements are conducted to study power generation in tune with the electro-catalytic activity. Finally, polarization and sustainability measurements are done on a comparatively larger fuel cell to check the size scalability. The results shows that the maximum power density is 108 mW/m2 and this multifunctional device can be fueled after every 12 h for continuous operation and with negligible de-activation of electro-catalyst. These studies opens a window for doing further advanced research in compost triggered electro-catalysis to make multifunctional fuel cell devices for solving environmental and energy issues together. Graphical abstract Image 1 Highlights • Compost directly act as a abundant and cheapest electro-catalyst. • Electro-catalytic activity leads to ammonium oxidation and generation of energy. • Fuel cell is made by variation in electrodes, compost and ammonium concentration. • Individual as well as joint physio-chemical/microbial action is possible. • This work elucidates the development of multifunctional fuel cell. [ABSTRACT FROM AUTHOR]

Treatment of sewage sludge with a thermal hydrolysis process (THP) followed by anaerobic digestion (AD) enables to boost biogas production and minimize residual sludge volumes. However, the reject water can cause inhibition to aerobic and anoxic ammonium-oxidizing bacteria (AerAOB & AnAOB), the two key microbial groups involved in the deammonification process. Firstly, a detailed investigation elucidated the impact of different organic fractions present in THP-AD return liquor on AerAOB and AnAOB activity. For AnAOB, soluble compounds linked to THP conditions and AD performance caused the main inhibition. Direct inhibition by dissolved organics was also observed for AerAOB, but could be overcome by treating the filtrate with extended aerobic or anaerobic incubation or with activated carbon. AerAOB additionally suffered from particulate and colloidal organics limiting the diffusion of substrates. This was resolved by improving the dewatering process through an optimized flocculant polymer dose and/or addition of coagulant polymer to better capture the large colloidal fraction, especially in case of unstable AD performance. Secondly, a new inhibition model for AerAOB included diffusion-limiting compounds based on the porter-equation, and achieved the best fit with the experimental data, highlighting that AerAOB were highly sensitive to large colloids. Overall, this paper for the first time provides separate identification of organic fractions within THP-AD filtrate causing differential types of inhibition. Moreover, it highlights the combined effect of the performance of THP, AD and dewatering on the downstream autotrophic nitrogen removal kinetics. [ABSTRACT FROM AUTHOR]

Inhibition by ammoniacal nitrogen, consisting of free ammonia (NH 3 ) and ammonium ion (NH 4 + ), has been widely investigated for anaerobic digestion. However, despite the large amount of research on the subject, ammoniacal nitrogen inhibition still threatens many anaerobic digesters. This paper presents (i) a method to reliably characterise ammoniacal nitrogen inhibition and (ii) a robust inhibition modelling approach. Results showed that NH 3 and NH 4 + inhibition need to be jointly determined, which can only be done by performing inhibition tests at various total ammoniacal nitrogen (TAN) concentrations and pH values. These test conditions were reliably achieved using the salts NH 4 HCO 3 and NH 4 Cl without pH adjustment, rather than by using NH 4 Cl with pH adjustment. The use of only salts showed a lower pH change during the inhibition test (∼1.5 days), thereby decreasing the uncertainty in TAN speciation and strengthening the test and model outputs. A threshold inhibition function satisfactorily described (R 2  > 0.99) the joint inhibition of NH 3 and NH 4 + on three distinct inocula, and provided a better description of the inhibition testing results than a non-competitive inhibition function (R 2 ∼0.70). The key advantage of the proposed threshold inhibition function is its capacity to identify the inhibition lower limit (concentration where inhibition starts; KI min ) and upper limit (concentration where inhibition is complete; KI max ). The threshold inhibition function also identifies the 50% inhibition concentration (KI 50 ) at the midpoint of KI min and KI max . Finally, experimental and model results show that at pH 7.3–7.7 and TAN concentrations above 2000 mgN·L −1 , both NH 3 and NH 4 + contribute significantly to overall inhibition. [ABSTRACT FROM AUTHOR]

In cold areas, nitrogen removal performance of wastewater treatment plants (WWTP) declines greatly in winter. This paper systematically describes the enhancement effect of a periodic reverse electrocoagulation technology on biological nitrogen removal at low temperatures. The study showed that in the lab-scale systems, the electrocoagulation technology improved the biomass amount, enzyme activity and the amount of nitrogen removal bacteria ( Nitrosomonas , Nitrobacter , Paracoccus , Thauera and Enterobacter ). This enhanced nitrification and denitrification of activated sludge at low temperatures. In the pilot-scale systems, the electrocoagulation technology increased the relative abundance of cold-adapted microorganisms ( Luteimonas and Trueperaceae ) at low temperatures. In a full-scale industrial WWTP, comparison of data from winter 2015 and winter 2016 showed that effluent chemical oxygen demand (COD), NH 4 + -N, and NO 3 − -N reduced by 10.37, 3.84, and 136.43 t, respectively, throughout the winter, after installation of electrocoagulation devices. These results suggest that the electrocoagulation technology is able to improve the performance of activated sludge under low-temperature conditions. This technology provides a new way for upgrading of the performance of WWTPs in cold areas. [ABSTRACT FROM AUTHOR]

Liquid-liquid equilibrium data of aqueous two-phase systems (ATPS) composed by L35 triblock copolymer + ammonium electrolytes (nitrate, NO 3 − ; tartrate, C 4 H 4 O 6 2− ; phosphate, HPO 4 2− ; acetate, C 2 H 3 O 2 − ) + water, at different temperatures (298.2 and 313.2 K) are presented in this paper. The experimental ATPS data were correlated with the original and modified non-random two-liquid (NRTL) for predicting energetic parameters of the studied systems. The results were satisfactory with global root mean square deviations (33 tie-lines) of the 2.36% and 2.53% for the original and modified models, respectively. The effect of the temperature and electrolyte nature on the biphasic area position was investigated. The increase of the temperature promoted a slight increase in the two-phase region indicating the endothermic character of the phase splitting. The increase in the temperature also promoted a rise in the module of the slope of the tie-lines. The anions ability to promote phase separation followed the order: HPO 4 2−  > C 4 H 4 O 6 2−  > NO 3 −  > C 2 H 3 O 2 − . [ABSTRACT FROM AUTHOR]

Enhanced ammonia (NH 3 ) emissions and deposition caused negative effects on air quality and ecosystems. Precipitation is an efficient pathway to remove NH 3 and particulate ammonium (p-NH 4 + ) from the atmosphere into ecosystems. However, precipitation scavenging of p-NH 4 + in chemical transport models has often considered fine p-NH 4 + , with inadequate constraints on NH 3 and coarse p-NH 4 + . Based on distinct δ 15 N values between NH 3 and NH 4 + in PM 2.5 (particulate matters with aerodynamic diameters ≤ 2.5 μm) or TSP (total suspended particulates), this paper interpreted intra-event variations of precipitation NH 4 + concentrations and δ 15 N values (δ 15 N-NH 4 + values) at Guiyang (Xiao et al., 2015). Generally decreased NH 4 + concentrations across rain events reflected decreasing scavenging of NH 3 and p-NH 4 + . Using a Bayesian isotope mixing model, we found that differing contributions between 15 N-depleted NH 3 and 15 N-enriched p-NH 4 + were responsible for the three-stage variations of intra-event δ 15 N-NH 4 + values. The decreases of δ 15 N-NH 4 + values across the first and third stages indicated more decreases in scavenging p-NH 4 + than NH 3 , while the increases of δ 15 N-NH 4 + values across the second stage were resulted primarily from more increases in scavenging p-NH 4 + (particularly fine p-NH 4 + ) than NH 3 . These results stressed influences of differing scavenging between NH 3 and p-NH 4 + on precipitation δ 15 N-NH 4 + values, which should be considered in modeling precipitation scavenging of atmospheric p-NH 4 + . [ABSTRACT FROM AUTHOR]

Abstract: The polymer–ammonium complexes are an important class of proton conducting polymer electrolytes. In this work, poly(ethylene oxide) (PEO)–NH4SCN electrolytes were prepared over a large range of the salt content, and their FT-IR spectra were measured at room temperature. Based on the assignments of each band in the spectral envelope of SCN−1, their relative intensities are determined by the use of FT-IR technique. Following the experimental results and spectral analyses, this paper reports the interactions, the various ionic associations, the changes of the ionic association with NH4SCN content, and the characteristics of structure in PEO–NH4SCN electrolytes. It is shown that the hydrogen bonds of PEO and NH4SCN exert the great effect to the ionic association, the interactions of PEO with NH4SCN, and PEO crystallinity, in particular, under the condition of high NH4SCN content. In addition, the differences of ionic association among PEO–NaSCN, PEO–KSCN and NH4SCN electrolytes are also compared in this paper. [Copyright &y& Elsevier]

This paper is Part II in a pair of papers that examines the results of the Community Multiscale Air Quality (CMAQ) model version 4.5 (v4.5) and discusses the potential explanations for the model performance characteristics seen. The focus of this paper is on fine particulate matter (PM2.5) and its chemical composition. Improvements made to the dry deposition velocity and cloud treatment in CMAQ v4.5 addressing compensating errors in 36-km simulations improved particulate sulfate (SO4 2−) predictions. Large overpredictions of particulate nitrate (NO3 −) and ammonium (NH4 +) in the fall are likely due to a gross overestimation of seasonal ammonia (NH3) emissions. Carbonaceous aerosol concentrations are substantially underpredicted during the late spring and summer months, most likely due, in part, to a lack of some secondary organic aerosol (SOA) formation pathways in the model. Comparisons of CMAQ PM2.5 predictions with observed PM2.5 mass show mixed seasonal performance. Spring and summer show the best overall performance, while performance in the winter and fall is relatively poor, with significant overpredictions of total PM2.5 mass in those seasons. The model biases in PM2.5 mass cannot be explained by summing the model biases for the major inorganic ions plus carbon. Errors in the prediction of other unspeciated PM2.5 (PMOther) are largely to blame for the errors in total PM2.5 mass predictions, and efforts are underway to identify the cause of these errors. [Copyright &y& Elsevier]

This paper discusses the first-time study of a naphthalene-based fluorescent probe—naphthalene-2,3-dicarboxaldehyde (NDA), in combination with merging-zone flow injection analysis for the automated fluorescence determination of ammonium. The determination was contingent on detecting the fluorescent product of NDA-SO 3 2--NH 4 +, which has maximum excitation and emission wavelengths of 508 nm and 564 nm, respectively. And the possible sensing mechanism of NDA-NH 4 + was proposed. The effects of the reaction parameters, including reagent concentrations, reaction flow rate, coil length, reaction temperature, and pH were optimized. Under optimal conditions, this method afforded a sampling rate of 8 h−1, a limit of detection of 0.045 μmol L−1, and RSD of 3.68% (n = 14) with 1.50 μmol L−1 ammonium, and the calibration range was 0.045–6.00 μmol L−1. Examination of the organic nitrogen interference confirmed that the method attracts minimal interference from organic nitrogen, and the stability of the NDA reagent facilitates its field application. Other exhibited advantages include low reagent consumption and high automation; the method has been utilized in the successful determination of ammonium in freshwater and rainwater. The development of NDA applications for ammonium determination also provides more options for fluorometric determination of ammonium. [Display omitted] • An automated method of ammonium in combination with merging-zone flow injection analysis. • The first-time study of a naphthalene-based fluorescent probe as the fluorescent probe for ammonium determination. • A possible NDA-NH 4 + sensing mechanism. • NDA-NH 4 + fluorescence derivatization product with excellent spectral properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synergistic activation with copper–ammonium significantly improved the flotation recovery of malachite. • The number of active sites on malachite surfaces increased after synergistic activation. • Synergistic activation was beneficial to the formation of copper sulfide species on malachite surfaces. • The surface hydrophobicity of malachite enhanced after synergistic activation. Malachite, as an important copper oxide mineral, is mainly separated and recovered from ores using sulfidization xanthate flotation method. In this paper, copper ions and ammonium salts were used as activators to modify the malachite surface, which improved its reactivity and improved the sulfidization and hydrophobicity of the mineral surface. Micro-flotation test results show that the flotation recovery of malachite can be greatly improved by this synergistic activation system, compared with that upon treatment in a direct sulfidization system. Zeta potential, XPS and ToF-SIMS analysis showed that the content of highly active cuprous sulfide species and copper sites on the malachite surface increased after the copper–ammonium synergistic activation treatment. FTIR characterization and contact angle measurement indicated that more xanthate components were stably adsorbed on the malachite mineral surface after the synergistic activation of the copper–ammonium, thereby increasing the hydrophobicity of the surface. Therefore, the synergistic activation not only resulted in the enhanced sulfidization of malachite surfaces, but also enhanced the reactivity and hydrophobicity of malachite surfaces, thus promoting the hydrophobic flotation of malachite. This represents a new concept and process for the efficient flotation recovery of oxidized copper minerals. [ABSTRACT FROM AUTHOR]

This paper describes the recovery of gold (Au) from shredder light fraction (SLF) of a recycling plant by flotation and leaching. SLF is typically sent to landfills as waste, but it still contains substantial amounts of Au, and other metals like Cu and Fe. The SLF sample used in this study contains 0.003% of Au, 12% of Cu, and 10% of Fe. Flotation results showed that over 99% of Au and 50% of combustibles were recovered in froth while most of the base metals were recovered in tailing. SEM-EDX of froth products indicates that Au floated via two mechanisms: (1) flotation of Au-plated plastic particles, and (2) agglomeration of fine Au particles together with plastic particles due to kerosene-induced hydrophobic-hydrophobic interactions followed by the flotation of these agglomerated particles. Combustibles in froth/tailing were analyzed by ATR-FTIR, and the results showed that plastics in the froth were mostly sulfonated polystyrene (PS) and acrylonitrile butadiene styrene (ABS) while those in tailing were polyurethane (PU) and polyethylene terephthalate (PET). Contact angle measurements of plastic particles suggest that PS and ABS are more hydrophobic than PU and PET. Most of the base metals in the tailing had either bent or twisted shapes because they were mostly made up of wires. In flotation, these large and heavy particles are unaffected by bubbles and simply sink. Leaching results using ammonium thiosulfate solutions showed that Au extraction increased from 33 to 51% after flotation. [ABSTRACT FROM AUTHOR]

Synechococcus sp. UTEX LB2380 is a coastal strain of a cosmopolitan cyanobacterial genus. In coastal waters, N and light availability are highly variable and their interplay may influence C allocation and photosynthetic performance. In this paper, we compared the impact of nitrogen (N) limitation and energy (light, E) limitation on phycobilisome composition and photosynthesis, in the presence of either NO 3 − or NH 4 + . Our hypothesis was that the phycobilisome composition would be influenced by the factor limiting growth. Our results show that N-limited cells adjusted their phycobilisome antenna to minimize N utilization, whereas E-limited cells had a phycobilisome composition tailored to alleviate E deficiency. The N-source was relevant for the pigment composition, under both limitations. When N limited growth, excess energy management may become important to decrease the risk of photoinhibition and oxidative stress; when the sink of electrons constituted by NO 3 − reduction was not present, the cells tended to decrease their phycobiliprotein content, possibly in order to minimize the size of PSII antennas and decrease excitation. When energy was limiting, the energy saved for N assimilation in NH 4 + -grown cells was invested in antenna pigments to allow for a higher energy input. [ABSTRACT FROM AUTHOR]

In organic-rich shallow habitats, benthic macrofauna is known to play a major role in the geochemical functioning of surficial sediments through its metabolism, as well as its bioirrigation and/or bioturbation activity. In this paper, the effects of benthic macrofauna on metabolic fluxes at the sediment-water interface were studied at four dates, from winter to late summer, on two major macrobenthic communities of the eastern English Channel (macrotidal system): the fine sand Abra alba community (2 stations) and the sandy gravel Ophiothrix fragilis community (1 station). Oxygen and ammonium fluxes showed temporal changes that could be attributed to the variation of sea water temperature. Once the effect of temperature removed (using Q 10  = 2.5), the average fauna mediated fluxes (F Fauna ) represented respectively 77% and 76% of average total fluxes. Considering the whole dataset, species number and biomass showed a significant correlation with fauna mediated fluxes of O 2 and NH 4 + , while the relationships with abundance were not significant. The species composition of the community might influence ecosystem functioning, but in the present study, functional groups have a very poor relationship with F Fauna (O 2 ) and F Fauna (NH 4 + ). Despite the presence of engineer species, establishing general and simple rules to link macrofaunal parameters to functional attributes remains very difficult, suggesting that communities rather followed the idiosyncrasy and rivet hypothesis. [ABSTRACT FROM AUTHOR]

Oxygen reduction reaction (ORR) plays an important role in microbial fuel cell (MFC) performance. But the poison ions in wastewater may have a considerable effect on the activity of ORR catalysts. In this paper, we herein investigated the effect of typical NH 4 + and S 2− ions on the activity of different ORR catalysts, such as biomass derived carbon (bamboo charcoal (BC)), nitrogen doped graphene (N-G), iron/nitrogen co-doped graphene (Fe/N-G) and Pt/C catalysts. The results showed that the ORR catalytic activity was decreased in the presence of both NH 4 + and S 2− ions. In detail, the NH 4 + ion only had a slight and similar effect on the catalysts. However, the effect of S 2− on catalyst activity was much more negative, compared to that of NH 4 + . Notably, the BC, N-G and Fe/N-G catalysts exhibited a higher poison tolerance than Pt/C, indicating that BC, N-G and Fe/N-G catalysts could serve as poison tolerance ORR catalysts in both of NH 4 + and S 2− condition. [ABSTRACT FROM AUTHOR]

Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium pollution. These latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented. [ABSTRACT FROM AUTHOR]

This paper studies the tribological behavior of the ionic liquid methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([N 1888 ][NTf 2 ]) as additive at different concentrations (1.25, 2.50, 3.75 and 5.00 wt%) in a polar base oil (diester). A tribometer using a ball-on-disk reciprocating configuration under fully flooded lubrication was used at a frequency of 15 Hz, at three different loads (40, 80 and 120 N), stroke length of 4 mm, and duration of 45 min. Worn surface on the disk was studied by confocal microscopy, SEM and XPS. Main results showed similar coefficient of friction for all lubricant samples; but different wear results were found at different loads, probably related with the chemical states found for fluorine on the worn surface and the temperature-dependent adsorption-desorption processes. [ABSTRACT FROM AUTHOR]

Microalgae culture fed with ammonium may face the presence of nitrifying bacteria. The aim of this paper is to propose and analyze a nonlinear system which represents the dynamics of these two species (microalgae and nitrifying bacteria) in competition for nitrogen (present as ammonium and nitrate produced by nitrification) in a continuous process. The existence and local stability of system equilibria is studied. Reduction by conservation principle, perturbed systems and Lyapunov methods are used to provide sufficient conditions for the global asymptotic stability of the system equilibria. Finally, we illustrate our analysis with a case study, showing which operating conditions (dilution rate and pond depth) can promote the presence of nitrifiers with microalgae. [ABSTRACT FROM AUTHOR]

Zero valent iron (Fe0) has been proven to be a highly efficient adsorption material for cadmium in wastewater. However, how to deal with Fe0 after cadmium adsorption, restricts its industrialization. In this paper, we attempted to desorb cadmium from the post-adsorption material (Fe Cd) through ammoniacal leaching and recycle the Fe0. Desorption experiments, Infrared and SEM-EDS results showed leaching with (NH 4) 2 SO 4 and NH 3 ·H 2 O can effectively desorb cadmium from Fe Cd. Based on Ultraviolet spectrum, solution chemistry and quantum chemical analysis, cadmium on Fe Cd can combine with free ammonia and form Cd-NH 3 complexes. Then the complexes are transferred into the leached solution, achieving the desorption of cadmium. Subsequently, cadmium in leached solution was precipitated into Cd(OH) 2 , a high-grade cadmium product. Finally, the cadmium adsorption capability of regenerated Fe0 was roughly investigated, and the results showed that it has a better capability for cadmium adsorption than initial Fe0, which further guaranteed the recycle of Fe0. [Display omitted] • The ammoniacal leaching could achieve efficient and selective desorption of cadmium from Fe Cd. • The buffer action of (NH 4) 2 SO 4 and NH 3 ·H 2 O could greatly improve the leaching rate and efficiency. • The coordination of Cd(Ⅱ) and ammonia molecules can occur spontaneously, promoting the desorption of cadmium from Fe Cd. • The cadmium on Fe Cd was leached into liquor in the form of [Cd(NH 3) m (H 2 O) n ]2+. • The cadmium transferred to leached solution could be precipitated into high-grade Cd(OH) 2 through adjusting pH. [ABSTRACT FROM AUTHOR]

In this paper, an improved spectrofluorimetric method for the simultaneous and direct determination of ammonium and primary amine compounds is presented. The method is based on the derivatization of the analytes with o -phthaldialdehyde (OPA)/ N -acetylcysteine (NAC) reagent using high throughput microplates, and OPA/NAC ratio has been optimized in order to suppress interference of ammonium on primary amine determination. Direct measurement of these two parameters is therefore possible with a global procedure time that does not exceed 10 min. Excellent limits of detection of 1.32 μM and 0.55 μM have been achieved for ammonium and primary amines, respectively. Reagent stability issues have also been addressed and formulation of reagents solution is described for improved reagents shelf life. The proposed protocol was finally applied and validated on real samples such as wine samples, compost extracts and wastewater. [ABSTRACT FROM AUTHOR]

The present paper accounts for the vibrational spectroscopy and electrical characterization of a bis - tetrapropylammonium tetrachlorocobaltate grown at room temperature by slow evaporation of aqueous solution. The Raman spectra were studied in the range of 50–3500 cm −1 as a function of temperature of 318 K–421 K. The most important changes are observed for the band at 1032 cm −1 associated to δ ( C − C − C ) + t ( C H 2 ) + ω ( C H 2 ) . A detail analysis of the frequency and half-width is quantitatively described in term of an order-disorder model allowed to obtain information relative to the thermal coefficient and activation energy. The decrease of the activation energy with increasing temperature has been interpreted in term of a change in the re-orientation motion of the cationic parts [N(C 3 H 7 ) 4 ] + . Besides, the impedance measurements indicate that the electrical properties are strongly temperature dependent. Nyquist plots (−Z″versus Z′) show that the conductivity behavior is accurately represented by an equivalent circuit models which consists of a series combination of grains interior and grains boundary. The conductivity follows the Arrhenius relation with different activation energies and conduction mechanisms: three temperature regions with activation energies E a I = 0.78 eV and E a II = 0.81 eV and E a III = 0.93 eV. Furthermore, the modulus plots can be characterized by full width at half height or in term of a non-experiential decay function ϕ ( t ) = exp ( − 1 τ ) β . [ABSTRACT FROM AUTHOR]

Mechanisms through which microorganisms are impacted by surface application of ground cover and nutrient source in organic orchard management are not fully understood. Twelve ground cover (compost, wood chips, paper mulch, or mow-and-blow) by fertilizer (poultry litter, organic commercial, or a no-fertilizer control) treatment combinations were applied annually in April beginning in 2006, with soil collected in March 2007 and 2013 to determine the 1-year and 7-year effects of treatments on soil chemical and biological properties. Organic matter (OM) increased through time regardless of ground cover treatment averaged across fertilizers, with the greatest increase occurring with compost addition. Soil water content, microbial biomass N, ammonium-N, and nitrate-N were greater in 2013 than in 2007 at the 0–10 cm depth. Denaturing gradient gel electrophoresis analysis of denitrifying ( nirK) communities revealed that fertilizers did not have a significant main effect or interaction with ground covers. Greater nirK richness and diversity coincided with clustering of the nirK community composition within compost treatments, and greater dissolved organic carbon concentrations with compost compared to wood chip or mow-and-blow treatments in 2007. By 2013 nirK communities in wood chip and compost ground covers tended to cluster together. Furthermore, soil nirK richness increased significantly from 2007 to 2013 in compost and wood chip treatments and was greatest in 2013 under those two ground covers. Diversity with wood chip addition increased from among the least in 2007 to among the greatest in 2013. Greater richness and diversity and community composition in the nirK community within a year of compost additions and gradually over time with wood chip addition indicate potential for enhanced denitrification in low OM, organic apple orchard soil receiving compost and wood chips mulches. [ABSTRACT FROM AUTHOR]

The paper presents the results of application of hydrogen peroxide (H 2 O 2 ) for the optimization of the effects of ammonia nitrogen removal from domestic wastewater. The investigations were carried out at a model wastewater treatment plant consisting of a preliminary sedimentation tank and a sand filter with a horizontal flow of wastewater at a constant hydraulic load of 1.44 L/day. The efficiency of ammonia nitrogen removal was analyzed for different wastewater oxygenation levels: 0–10%, 10–20%, 20–30%, 30–40% and 40–50%, maintained by controlled application of a 0.1% H 2 O 2 solution. It was demonstrated that the gradual increase in oxygen concentration in treated wastewater due to H 2 O 2 dosing resulted in an increase in ammonia nitrogen removal from 39.0 to 81.2%. The best removal efficiency was obtained when the oxygenation level was in the range of 30–40%. It was also shown that application of hydrogen peroxide resulted in an effective removal of biochemical oxygen demand (BOD 5 ). The highest BOD 5 removal efficiency (94.3%) was obtained at the oxygenation level of 30–40%. The results indicate that oxygenation of wastewater with hydrogen peroxide can be applied for the optimization of the nitrification process in wastewater treatment plants. [ABSTRACT FROM AUTHOR]

Ammonia gas injection is a promising technique for the remediation of uranium within the vadose zone. It can be used to manipulate the pH of a system and cause co-precipitation processes that are expected to remove uranium from the aqueous phase and decrease leaching from the solid phase. The work presented in this paper explores the effects of ammonium and sodium hydroxide on the partitioning of uranium and dissolution of the kaolinite mineral in simplified synthetic groundwaters using equilibrium batch sorption and sequential extraction experiments. It shows that there is a significant increase in uranium removal in systems with divalent cations present in the aqueous phase but not in sodium chloride synthetic groundwaters. Further, the initial conditions of the aqueous phase do not affect the dissolution of kaolinite. However, the type of base treatment does have an effect on mineral dissolution. [ABSTRACT FROM AUTHOR]

This paper presents a fully integrated model to simulate coupled unsaturated-saturated flow and reactive transport of ammonium and nitrate, the two major nitrogen species. Based on our previous work of developing a coupled model of unsaturated-saturated flow and solute transport of a single species, the key contribution of this study is to develop a new mathematical model and the new computer code for a comprehensive list of biogeochemical reactions, which are necessary for simulating nitrogen reactive transport. The computer code is verified by comparing its simulated results with those obtained using another model for a synthetic case. Model calibration and validation are conducted for two real-world cases to simulate nitrogen reactive transport. The two cases are at the experimental plot scale with the sewage water irrigation and at the field scale with the septic tank effluent infiltration, respectively. Quantitative evaluation of the numerical modeling results indicates that the new model and computer code can accurately simulate field observations of moisture content, water table elevation, and nitrogen concentration. For example, the root mean square error for simulating moisture content can be as small as 0.01. The code is computationally efficient to capture spatial and temporal trends of nitrogen concentrations at the field scale with a large number of computational nodes and time steps. The fully integrated model is a promising tool for large-scale modeling of water flow and nitrogen transformation and transport under complex conditions in agricultural and urban environments. [ABSTRACT FROM AUTHOR]

The paper deals with the evaluation of the efficacy of both ammonium polyphosphate, APP, and alkaline lignin, AL, as suitable additives for the development of innovative and sustainable composites based on thermo-plasticized zein, TPZ. The chemical and physical interactions which occur between AL and APP and the secondary structure of thermo-plasticized zein were investigated by torque analysis and FTIR spectroscopy and were exploited to rationalize macroscopic properties such as the thermal stability, fire behavior and the mechanical properties. In details the fire behavior of the composites was evaluated by both cone calorimetry and self-sustained vertical combustion tests in order to simulate different fire scenario. The results highlighted that AL intercalates both the α -helix and β -sheets structures and thus improves the fire retardant behavior of composites in the vertical burning scenario by enabling the withdrawal effect of the film from flame due to the removal of PEG plasticizer during the burning test. On the other side, APP enhances the fire resistance of composites exposed to pool forced combustion due to an enhanced charring effect which protects the substrate during burning. Finally the composite containing simultaneously 10 wt% APP and 3 wt% AL exhibited excellent fire resistance behavior in different fire scenario and satisfying mechanical properties with a toughness which is around 30% higher than that of pristine TPZ. Due to this peculiar combination of functional and structural properties the composite materials may be considered as potential substitutes of traditional polymeric materials in several application fields (i.e packaging, electrical components, …). [ABSTRACT FROM AUTHOR]