Arsenic-bearing synthetic jarosite [KFe3(SO4)2(OH)6] was characterized to elucidate the form of the arsenic. The XANES spectra indicate that the As occurs exclusively as As5+, nominally as AsO4, consistent with the valence state of the arsenic in the reagents used for the syntheses. X-ray-diffraction analyses show that at least 9.9 wt.% AsO4 can be structurally incorporated in the jarosite. Cel...

ABSTRAKBiji alpukat dapat diekstrak menjadi zat warna alam karena mengandung senyawa tanin yang menimbulkan cokelat atau kecokelatan. Kelemahan dalam proses pewarnaan tekstil yakni memiliki ketahanan luntur rendah. Oleh itu, pada pencelupan bahan dengan dibutuhkan fiksasi agar baik. Pewarna alami dari biji telah diterapkan kain katun. Ketahanan pewarna diuji memvariasikan massa tawas sebagai te...

Within the southeast Canada and northeast USA region, a peak in sulphate (SO4 ) concentration has been reported for some streams following periods of substantial catchment drying during the summer months (ON, Canada; VT, NH and NY, USA). However, it is currently unclear if a SO4 2response to seasonal drying is widespread across the broader region, or to what extent the level of response varies ...

a novel nano – sized  manganese (ii) coordination polymer, [{mn(ncs)2(l)(h2o)2}(l)]n  , (1) (l- = 4,4'-bipyridine), have been synthesized by a sonochemical process and characterized by scanning electron microscopy (sem), x-ray diffraction (xrd), ir spectroscopy and elemental analysis.  direct calcination of the single crystals and nano-sized compound 1 at 400 0c under air atmosphere yields...

this paper presents results of hydro-chemical processes controlling groundwater chemical composition, using an integrated application of hierarchical cluster analysis and factor analysis of a major ion data set of groundwater from mighan playa aquifer. cluster analysis classified samples into four clusters(a, b, c and d) according to their dominant chemical composition: cluster a (dominant comp...

Raman spectroscopy at 298 and 77K has been used to study the secondary uranyl mineral johannite of formula (Cu(UO2)2(SO4)2(OH)2 x 8H2O). Four Raman bands are observed at 3593, 3523, 3387 and 3234cm(-1) and four infrared bands at 3589, 3518, 3389 and 3205cm(-1). The first two bands are assigned to OH- units (hydroxyls) and the second two bands to water units. Estimations of the hydrogen bond dis...

Variations in the Mg, Ca, Sr, and SO4 concentrations of paleoseawater can affect the chemical exchange between seawater and oceanic basalt in hydrothermal systems at midocean ridges (MOR). We present a model for evaluating the nature and magnitude of these previously unappreciated effects, using available estimates of paleoseawater composition over Phanerozoic time as inputs and 87Sr/86Sr of op...

Mutant strains of the yeast Saccharomyces cerevisiae which lack functional Cu,Zn superoxide dismutase (SOD-1) do not grow aerobically unless supplemented with methionine. The molecular basis of this O2-dependent auxotrophy in one of the mutants, Dscd1-1C, has been investigated. Sulfate supported anaerobic but not aerobic mutant growth. On the other hand, cysteine and homocysteine supported aero...

Starting from a synthetic sample with composition Al2(SO4)3·16.6H2O, the high-temperature- and moisture-dependent behavior of alunogen has been unraveled by TGA measurements, in situ powder X-ray diffraction as well as by gravimetric moisture sorption/desorption studies. Heating experiments using the different techniques show that alunogen undergoes a first dehydration process already starting ...

Intramembranous charge movement was measured in cut twitch fibers mounted in a double Vaseline-gap chamber with either a tetraethylammonium chloride (TEA.Cl) or a TEA2.SO4 solution (13-14 degrees C) in the central pool. Charge vs. voltage data were fitted by a single two-state Boltzmann distribution function. The average values of V (the voltage at which steady-state charge is equally distribut...