Incorporation Of NH4 Research Articles

Mechanism study of synergistic aluminum extraction and purification by ammonium for high-value conversion of secondary aluminum dross

Secondary aluminum dross (SAD) constitutes a significant volume of hazardous solid waste with huge productions. Balancing extraction efficiency and purity within the current resourcing recovery process proves challenging and impedes high-value conversion. Consequently, the NH4HSO4-H2SO4 system was employed in this study to convert SAD into high-purity alumina nanoparticles, and the effect of ammonium was investigated. The results indicated that the leaching rate reached 85.98 % under the optimum conditions (170 °C, [Htot]=12 mol/L, 16/1,6 h); the interaction of NH4+ and H+ with the oxygen atoms on the surface of Al2O3 was demonstrated to enhance the reactivity of the aluminum atoms by DFT calculations. The incorporation of NH4+ also facilitated the separation of aluminum by leveraging the temperature-dependent solubility characteristic of NH4Al(SO4)2. Molecular dynamics simulation revealed that NH4+ inhibits the diffusion rate of Al3+, thereby regulating the doping impurities such as Mg and Ca, and improving the purity of Al2O3 (95.29–99.64 %). Additionally, Nanoscale regulation was executed through the conversion of the NH4AlO(OH)HCO3 precursor and control. The sintering and agglomeration problems brought about by pyrolysis in atmospheres such as H2O and SO3 were avoided. This research provides reference for the high-value utilization of aluminum-containing solid waste.

Incorporation of NH4+ in flower-like zinc phosphate pigment to enhance the corrosion resistance of waterborne epoxy

Herein, the three-dimensional (3D) flower-like pigments of micro-nano scaled zinc phosphate (FZP) and ammonium zinc phosphate (FNZP) were successfully synthesized by hydrothermal synthesis method for improving the corrosion resistance of waterborne epoxy (WEP) coating. The micro-structures, chemical compositions and corrosion resistance of the as-obtained specimens were characterized by SEM, XRD, FT-IR, XPS and EIS, respectively. The results indicated that the 3D flower-like FZP and FNZP pigments were comprised of self-assembled nano-micro sheets with an average thickness of 20 nm ∼ 100 nm. Moreover, the remarkable enhancements of compactness and anticorrosion performance, especially for the FNZP-incorporated coating, were principally contributed to the well dispersibility and favourable solubility, which lengthened the permeation pathway and promoted the formation of passivation film.

Brightly luminescent (NH4)xCs1-xPbBr3 quantum dots for in vitro imaging and efficient photothermal ablation therapy

Herein, we report for the first time a facile strategy for the highly efficient (NH4)xCs1-xPbBr3 quantum dots (QDs). By modulating the amount of ammonium, (NH4)xCs1-xPbBr3 QDs with different photoluminescence (PL) quantum yields (QY) were synthesized. The results of X-ray diffraction and X-ray photoelectron spectroscopy showed that the crystal structure of (NH4)xCs1-xPbBr3 was altered by incorporation of NH4+ cations into the CsPbBr3 lattice. The (NH4)xCs1-xPbBr3 QDs showed enhanced PL QY, higher photostability, and long-term storage stability compared to CsPbBr3 QDs. Furthermore, (NH4)xCs1-xPbBr3 QDs could be conjugated with a photothermal dye (IR780) via a one-pot reaction using poly(styrene-co-maleic anhydride) and IR780-MPTS. To the best of our knowledge, the present work is the first attempt integrating perovskite QDs and phototherapeutic molecules into one system (abbreviated as PQD-IR780), demonstrating good water dispersibility and high photothermal conversion efficiency of 57.85%. In vitro experiments performed to examine subcellular uptake showed high fluorescence brightness was observed in HeLa, B16F1, and HepG2 cancer cells cultured with PQD-IR780. The results indicate that the internalization mechanism for uptaking of PQD-IR780 inside HeLa cells is energy-dependent and caveolin-mediated endocytosis. The in vitro cell viability assays and photothermal therapy revealed that PQD-IR780 showed good biocompatibility and can induce hyperthermia upon laser irradiation.

Ambient and cold‐temperature infrared spectra and XRD patterns of ammoniated phyllosilicates and carbonaceous chondrite meteorites relevant to Ceres and other solar system bodies

AbstractMg‐phyllosilicate‐bearing, dark surface materials on the dwarf planet Ceres have NH4‐bearing materials, indicated by a distinctive 3.06 μm absorption feature. To constrain the identity of the Ceres NH4‐carrier phase(s), we ammoniated ground particulates of candidate materials to compare their spectral properties to infrared data acquired by Dawn's Visible and Infrared (VIR) imaging spectrometer. We treated Mg‐, Fe‐, and Al‐smectite clay minerals; Mg‐serpentines; Mg‐chlorite; and a suite of carbonaceous meteorites with NH4‐acetate to exchange ammonium. Serpentines and chlorites showed no evidence for ammoniation, as expected due to their lack of exchangeable interlayer sites. Most smectites showed evidence for ammoniation by incorporation of NH4+ into their interlayers, resulting in the appearance of absorptions from 3.02 to 3.08 μm. Meteorite samples tested had weak absorptions between 3.0 and 3.1 μm but showed little clear evidence for enhancement upon ammoniation, likely due to the high proportion of serpentine and other minerals relative to expandable smectite phases or to NH4+ complexing with organics or other constituents. The wavelength position of the smectite NH4 absorption showed no variation between IR spectra acquired under dry‐air purge at 25 °C and under vacuum at 25 °C to −180 °C. Collectively, data from the smectite samples show that the precise center wavelength of the characteristic ~3.05 μm v3 absorption in NH4 is variable and is likely related to the degree of hydrogen bonding of NH4‐H2O complexes. Comparison with Dawn VIR spectra indicates that the hypothesis of Mg‐saponite as the ammonium carrier phase is the simplest explanation for observed data, and that Ceres dark materials may be like Cold Bokkeveld or Tagish Lake but with proportionally more Mg‐smectite.

Hybrid Perovskite, CH3NH3PbI3, for Solar Applications: An Experimental and Theoretical Analysis of Substitution in A and B Sites

The effect of the incorporation ofNH4+into the CH3NH3+sites of the tetragonal perovskite CH3NH3PbI3is analysed. Also, how it affects the introduction of Cd2+cations into Pb2+sites for a perovskite with 25 at.% ofNH4+is addressed. The incorporation ofNH4+into perovskite leads to a dramatic loss of crystallinity and to the presence of other phases. Moreover, the NH4PbI3was not found. The less formation of perovskite whenNH4+is incorporated is due to geometrical factors and not changes in the chemical state bonding of the ions. Also, the samples where perovskite is formed show similar band gap values. A slight increase is observed for samples withx=0.5and 0.75. For the sample withx=1, a drastic increase of the band gap is obtained. Periodic-DFT calculations agree with the experimental structural tendency whenNH4+is incorporated and the density of states analysis confirmed the experimental band gap. The perovskite with 25 at.% ofNH4+was selected for studying the effect of the concentration of Cd on the structural and electronic properties. The theoretical band gap values decreased with the Cd concentration where the narrowing of Cd s-states in the conduction band plays an important role.

NH4-doped anodic WO3 prepared through anodization and subsequent NH4OH treatment for water splitting

Tungsten trioxide (WO3) prepared by anodization of a W foil was doped with NH4 through NH4OH treatment at 450°C. Since aqueous NH4OH was used during doping instead of NH3 gas, the treatment step does not require complicated annealing facilities. Moreover, the state of doped N is a form of NH3-W instead of W2N, which lowers the bandgap but increases photocorrosion. We found that incorporation of NH4 into WO3 leads to reduction of the bandgap from 2.9eV to 2.2eV, regardless of the amount of NH4OH treatment, lowering the onset potential and increasing the current density at fixed potential for oxygen evolution reaction under illumination. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were employed to investigate the surface morphologies, crystallinities of tungsten oxides and existence of NH4 doping, respectively. The bandgap energy was determined by UV–Vis spectroscopy to measure the transmittance and refraction. The water splitting performance of each sample was measured by electrochemical linear sweep voltammetry in a 3-electrode configuration under illumination.

Ammonium Adsorption on a Pine-bark Growing Medium

Abstract Pine bark was shown to adsorb 1.5 mg of N/g of bark when NH4 solutions were leached through the bark. Increasing pH of bark increased adsorbed NH4. At pH 3.3, only NH4 was adsorbed to bark particles when a fertilizer solution containing NH4, Ca, K, and Mg was applied. However, adsorption of NH4 and other cations increased as pH was increased from 3.8 to 5.8. These data indicate that 2 types of sites exist for the adsorption of NH4 to pine bark. One site is effective at lower pH; the other is active as pH increases. Daily application of 2.5 cm of water containing 50 ppm NH4 required 20 days for equilibration to occur so as to satisfy all binding sites. Thus, incorporation of NH4 into a pine-bark medium prior to planting may be advisable to prevent low N levels from occurring in the container solution due to NH4 binding when plants are first planted and fertilized.

Sphingolipid biosynthesis and vitamin K metabolism in Bacteroides melaninogenicus

B. melaninogenicus provides a unique system for the study of the biosynthesis of an important group of lipids, the phosphosphingolipids. Sphingolipid biosynthesis can be repressed and induced by depletion and restoration of vitamin K. At least one enzyme involved in sphingolipid biosynthesis from the microorganism can be solubilized and so purified by conventional methods. Pathways involved in biosynthesis may differ from hitherto postulated pathways, for example, the incorporation of NH4+ into ethanolamine residue of ceramide phosphorylethanolamine. Moreover, the derivation of mutants defective in steps in sphingolipid biosynthesis would be of great value in these studies.