Antimony

About: Antimony is a research topic. Over the lifetime, 11450 publications have been published within this topic receiving 155660 citations. The topic is also known as: Sb & element 51.

Antimony oxidation and adsorption by in-situ formed biogenic Mn oxide and Fe-Mn oxides.

Abstract: Antimony (Sb), which can be toxic at relatively low concentrations, may co-exist with Mn(II) and/or Fe(II) in some groundwater and surface water bodies. Here we investigated the potential oxidation and adsorption pathways of Sb (III and V) species in the presence of Mn(II) and Mn-oxidizing bacteria, with or without Fe(II). Batch experiments were conducted to determine the oxidation and adsorption characteristics of Sb species in the presence of biogenic Mn oxides (BMOs), which were formed in-situ via the oxidation of Mn(II) by a Mn-oxidizing bacterium (Pseudomonas sp. QJX-1). Results indicated that Sb(III) ions could be oxidized to Sb(V) ions by BMO, but only Sb(V) originating from Sb(III) oxidation was adsorbed effectively by BMO. Introduced Fe(II) was chemically oxidized to FeOOH, the precipitates of which mixed with BMO to form a new compound, biogenic Fe-Mn oxides (BFMO). The BMO part of the BFMO mainly oxidized and the FeOOH of the BFMO mainly adsorbed the Sb species. In aquatic solutions containing both As(III) and Sb(III), the BFMO that formed in-situ preferentially oxidized Sb over As but adsorbed As more efficiently. Chemical analysis and reverse transcription real-time polymerase chain reaction revealed that the presence of Fe(II), As(III) and Sb(III) accelerated the oxidation of Mn(II) but inhibited the activity of Mn-oxidizing bacteria. These results provide significant insights into the biogeochemical pathways of Sb, Mn(II) in aquatic ecosystems, with or without Fe(II).

Antimony speciation in alkaline sulfide solutions: role of zerovalent sulfur.

Abstract: Antimony is subject to a lower drinking water standard than arsenic, its notorious group 15 cohort in the periodic table. Both elements often co-vary in nature and are fairly soluble under reducing, alkaline conditions. Of the two, much less is known about the environmental chemistry of Sb. Measurements of Sb solubility in sulfidic solutions equilibrated with stibnite (Sb2S3) and orthorhombic sulfur reveal the existence of two new complexes that may control Sb behavior in many reducing environments. Formation reactions and stability constants (23 ± 2 °C) are HS- + S(s) + Sb2S3(s) ⇄ HSb2S5-, log K = −1.47 ± 0.17; and HS- + 2S(s) + Sb2S3(s) ⇄ Sb2S62- + H+, log K = −9.55 ± 0.07. The first complex is a mixed-valence SbIII,V complex; the second is an SbV complex. Their stability in sulfidic solutions may explain previously puzzling evidence of SbV in natural anoxic environments. Owing to these complexes, zerovalent S can enhance stibnite solubility up to 3 orders of magnitude. In neutral-to-alkaline, reducing ...

Determination of microgram amounts of antimony, bismuth, lead and tin in aluminium, iron and nickel-base alloys by non-aqueous atomic-absorption spectroscopy

Abstract: Microgram amounts of antimony, tin, lead and bismuth are extracted quantitatively from a 10 per cent. hydrochloric acid solution of the sample containing 2 per cent. of ascorbic acid and 6 per cent. of potassium iodide, in a single 30-s extraction, into a 5 per cent. solution of trioctylphosphine oxide in 4-methylpentan-2-one. The extract is then nebulised directly into the atomic-absorption burner flame.Use of this technique permits the determination of as little as 0·1 p.p.m. of these metals. The general precision of the proposed method is 5 ± 0·3 p.p.m.