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A spectroscopic method was developed for the determination of lignin contents in lignocellulosic biomass, based on a full dissolution of the biomass sample in a cysteine–sulfuric acid solution at room temperature.
The large concentrations of ultrafine particles consistently observed at high altitudes over the tropics represent one of the world’s largest aerosol reservoirs, which may be providing a globally important source of cloud condensation nuclei. However, the sources and chemical processes contributing to the formation of these particles remain unclear. Here we investigate new particle formation (NPF) mechanisms in the Amazon free troposphere by integrating insights from laboratory measurements, chemical transport modeling, and field measurements. To account for organic NPF, we develop a comprehensive model representation of the temperature-dependent formation chemistry and thermodynamics of extremely low volatility organic compounds as well as their roles in NPF processes. We find that pure-organic NPF driven by natural biogenic emissions dominates in the uppermost troposphere above 13 km and accounts for 65 to 83% of the column total NPF rate under relatively pristine conditions, while ternary NPF involving organics and sulfuric acid dominates between 8 and 13 km. The large organic NPF rates at high altitudes mainly result from decreased volatility of organics and increased NPF efficiency at low temperatures, somewhat counterbalanced by a reduced chemical formation rate of extremely low volatility organic compounds. These findings imply a key role of naturally occurring organic NPF in high-altitude preindustrial environments and will help better quantify anthropogenic aerosol forcing from preindustrial times to the present day.
The ability of atmospheric aerosols to impact climate through water uptake and cloud formation is fundamentally determined by the size, composition, and phase (liquid, semisolid, or solid) of individual particles. Particle phase is dependent on atmospheric conditions (relative humidity and temperature) and chemical composition and, importantly, solid particles can inhibit the uptake of water and other trace gases, even under humid conditions. Particles composed primarily of ammonium sulfate are presumed to be liquid at the relative humidities (67 to 98%) and temperatures (–2 to 4 °C) of the summertime Arctic. Under these atmospheric conditions, we report the observation of solid organic-coated ammonium sulfate particles representing 30% of particles, by number, in a key size range (<0.2 µm) for cloud activation within marine air masses from the Arctic Ocean at Utqiagvik, AK. The composition and size of the observed particles are consistent with recent Arctic modeling and observational results showing new particle formation and growth from dimethylsulfide oxidation to form sulfuric acid, reaction with ammonia, and condensation of marine biogenic sulfate and highly oxygenated organic molecules. Aqueous sulfate particles typically undergo efflorescence and solidify at relative humidities of less than 34%. Therefore, the observed solid phase is hypothesized to occur from contact efflorescence during collision of a newly formed Aitken mode sulfate particle with an organic-coated ammonium sulfate particle. With declining sea ice in the warming Arctic, this particle source is expected to increase with increasing open water and marine biogenic emissions.
The production of very pure molybdenum, free of Re even at ultratrace levels, is extremely important in meeting target purity specifications during the production of 99 Mo for medical applications. Here we propose two methods for separating ultratrace levels of Re from a bulk Mo matrix using either solvent extraction or extraction chromatography, combined with inductively coupled plasma quadrupole mass spectrometry (ICP-MS) detection. Re is extracted (D > 70) from solutions in sulfuric acid as a complex with tri-n-butyl phosphate. Scrubbing and washing steps result in total decontamination factors for Mo up to 1,700 for solvent extraction and 3,500 for extraction chromatography. Re is stripped into a 3 M NH 4 OH matrix and analyzed by ICP-MS. Detection (L D ) and quantification (L Q ) limits were optimized by matrix-matching to allow detection of Re in strip solutions at levels of L D = 0.1 ng Re/g-Mo and L Q = 0.3 ng Re/g-Mo in Mo powder samples. By employing these two extraction methods, excellent recoveries of Re from bulk Mo are achieved, and the L Q is improved by a factor of 5 x 10 4 .
Acoustic spalling is a promising technique for substrate reuse in the fabrication of gallium arsenide (GaAs) photovoltaic cells. However, the acoustic spalling process can leave the substrate with areas of rough surface morphology that can interfere with subsequent cell growth and processing. In this work, we investigate the use of wet etchants to smooth the surface of acoustically spalled GaAs substrates. We evaluated six different etchants. Of those tested, an 8:1:1 mixture of sulfuric acid, hydrogen peroxide, and water at 30 degrees C and a moderate stirring rate showed the greatest roughness reduction per mass loss while producing the desired morphology. This etchant was then applied to an acoustically spalled 2-inch GaAs wafer. A single-junction GaAs cell was then grown via metalorganic vapor-phase epitaxy on this substrate, an acoustic spalled substrate without a smoothing etch, and an epi-ready substrate. Use of the 8:1:1 H2SO4:H2O2:H2O etchant produced cells an average efficiency of 12.8% as compared to that of 2.0% grown on the unetched acoustically spalled substrate and 16.3% grown on the epi-ready substrate. The results of this work demonstrate that wet etching is a viable method for smoothing the surface of spalled GaAs substrates, paving the way for substrate reuse via acoustic spalling at efficiencies that approach growth on epi-ready substrates.
We developed a new on-line hyphenated flow injection analysis technique (FI-EQCM-ICP-OES) that allows electrochemical deposition and stripping with mass detection and elemental analysis. This technique was used to study a new system for electrochemical recovery of silver from a 0.5 mM Ag + /5 mM Cu 2+ /0.5 M H 2 SO 4 solution by pulsed electrodeposition with redox replacement (EDRR) in a small flow cell. The metal ions in a 500 μ l sample are injected into the sulfuric acid carrier stream and deposited onto an electrochemical quartz crystal microbalance (EQCM) electrode housed in a 50 μ l flow cell. The deposits are subsequently stripped off electrochemically in the same cell and analyzed downstream in an ICP-OES. The stripped metal layer was found to be composed of Ag with no detectable Cu for a redox replacement time of 10 s, and 91 wt.% Ag–9 wt.% Cu for a redox replacement time of 5 s. Microscopy measurements demonstrated that the electrode was covered with silver particles, some of which contain Cu in the case of the 5 s replacement time. This technique allowed the study of mass changes on the electrode during electrodeposition and open circuit times in each EDRR cycle in flowing solutions.
Sr4Al6O12SO4 crystallizes in the cubic I-43m space group. The structure is three-dimensional and consists of two sulfuric acid molecules and one Sr2Al3O6 framework. In the Sr2Al3O6 framework, Sr2+ is bonded in a distorted trigonal non-coplanar geometry to three equivalent O2- atoms. All Sr–O bond lengths are 2.48 Å. Al3+ is bonded to four equivalent O2- atoms to form corner-sharing AlO4 tetrahedra. All Al–O bond lengths are 1.76 Å. O2- is bonded in a 3-coordinate geometry to one Sr2+ and two equivalent Al3+ atoms.
(NH4)2SO4 is Iron carbide-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four ammonium molecules and four azanium;sulfuric acid molecules.
Mg(H2O)6(NH4)2(SO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four ammonium molecules, two magnesium;hexahydrate molecules, and four sulfuric acid molecules.
(NH4)2SO4 is Iron carbide-derived structured and crystallizes in the orthorhombic Pna2_1 space group. The structure is zero-dimensional and consists of eight ammonium molecules and four sulfuric acid molecules.
Ca3SiCH30O21SO4 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional and consists of two sulfuric acid molecules and one Ca3SiCH30O21 framework. In the Ca3SiCH30O21 framework, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.43–2.59 Å. Si4+ is bonded in an octahedral geometry to six O2- atoms. All Si–O bond lengths are 1.80 Å. C4+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All C–O bond lengths are 1.30 Å. There are ten inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.72 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the eighth H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.66 Å) H–O bond length. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one C4+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+, one Si4+, and one H1+ atom. In the fifth O2- site, O2- is bonded in a water-like geometry to one Ca2+ and two H1+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+, one Si4+, and one H1+ atom. In the seventh O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms.
V(H2O)6H2OSO4 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four sulfuric acid molecules, four water molecules, and four V(H2O)6 clusters. In two of the V(H2O)6 clusters, V2+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of V–O bond distances ranging from 2.16–2.19 Å. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one V2+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one V2+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to one V2+ and two H1+ atoms. In two of the V(H2O)6 clusters, V2+ is bonded in an octahedral geometry to six O2- atoms. There are four shorter (2.16 Å) and two longer (2.23 Å) V–O bond lengths. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the second H1+ site, H1+ is bonded in a distorted single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one V2+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one V2+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to one V2+ and two H1+ atoms.
(NH4)3H(SO4)2 crystallizes in the monoclinic P2/c space group. The structure is zero-dimensional and consists of twelve ammonium molecules and four sulfate, hydrogen, compd. with sulfuric acid (1:1) molecules.
Te2O3SO4 crystallizes in the orthorhombic Pmn2_1 space group. The structure is two-dimensional and consists of two sulfuric acid molecules and one Te2O3 sheet oriented in the (0, 1, 0) direction. In the Te2O3 sheet, Te4+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Te–O bond distances ranging from 1.94–1.99 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Te4+ atoms. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Te4+ atoms.
H2SO4 is Protactinium-like structured and crystallizes in the monoclinic Cc space group. The structure is zero-dimensional and consists of four sulfuric acid molecules. there are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. S6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.44–1.58 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the second O2- site, O2- is bonded in a distorted water-like geometry to one H1+ and one S6+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one H1+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one S6+ atom.
H2SO4 crystallizes in the monoclinic Cc space group. The structure is zero-dimensional and consists of four sulfuric acid molecules. there are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. S6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.43–1.59 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one H1+ and one S6+ atom. In the third O2- site, O2- is bonded in a water-like geometry to one H1+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one S6+ atom.
H4SO5 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four sulfuric acid, monohydrate molecules. there are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.16 Å) and one longer (1.28 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. S6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.44–1.60 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the second O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the third O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the fourth O2- site, O2- is bonded in a water-like geometry to one H1+ and one S6+ atom. In the fifth O2- site, O2- is bonded in a water-like geometry to one H1+ and one S6+ atom.
CuC2H12(N4S)2(H2O)4SO4 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four sulfuric acid molecules, sixteen water molecules, and four CuC2H12(N4S)2 clusters. In each CuC2H12(N4S)2 cluster, Cu2+ is bonded in a distorted rectangular see-saw-like geometry to two N1- and two S2- atoms. There are one shorter (2.03 Å) and one longer (2.05 Å) Cu–N bond lengths. There are one shorter (2.25 Å) and one longer (2.27 Å) Cu–S bond lengths. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a distorted trigonal planar geometry to two N1- and one S2- atom. Both C–N bond lengths are 1.34 Å. The C–S bond length is 1.72 Å. In the second C4+ site, C4+ is bonded in a distorted trigonal planar geometry to two N1- and one S2- atom. Both C–N bond lengths are 1.34 Å. The C–S bond length is 1.72 Å. There are eight inequivalent N1- sites. In the first N1- site, N1- is bonded in a distorted water-like geometry to one N1- and two H1+ atoms. The N–N bond length is 1.41 Å. Both N–H bond lengths are 1.03 Å. In the second N1- site, N1- is bonded in a distorted water-like geometry to one N1- and two H1+ atoms. The N–N bond length is 1.41 Å. Both N–H bond lengths are 1.03 Å. In the third N1- site, N1- is bonded in a 2-coordinate geometry to one C4+ and one H1+ atom. The N–H bond length is 1.04 Å. In the fourth N1- site, N1- is bonded in a 3-coordinate geometry to one C4+, one N1-, and one H1+ atom. The N–N bond length is 1.41 Å. The N–H bond length is 1.04 Å. In the fifth N1- site, N1- is bonded in a distorted water-like geometry to one Cu2+ and two H1+ atoms. Both N–H bond lengths are 1.04 Å. In the sixth N1- site, N1- is bonded in a distorted water-like geometry to one Cu2+, one N1-, and two H1+ atoms. Both N–H bond lengths are 1.04 Å. In the seventh N1- site, N1- is bonded in a 3-coordinate geometry to one C4+, one N1-, and one H1+ atom. The N–H bond length is 1.04 Å. In the eighth N1- site, N1- is bonded in a distorted trigonal planar geometry to one C4+, one N1-, and one H1+ atom. The N–H bond length is 1.04 Å. There are twelve inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a water-like geometry to one Cu2+ and one C4+ atom. In the second S2- site, S2- is bonded in an L-shaped geometry to one Cu2+ and one C4+ atom.