Antimony smelting process generating solid wastes and dust：Characterization and leaching behaviors

A large amount of solid waste has been produced by the antimony smelting process in the＂World Capital of Antimony＂, Xikuangshan area in China. This study comprehensively investigated the physical and chemical characteristics of the various solid wastes, as well as the leaching behavior of the solid wastes, which included water-quenched slag,arsenic-alkali residue, desulfurized slag and blast furnace dust. These four types of waste were enriched in a variety of heavy metals and metalloids and more specifically with As and Sb levels up to 8.6 × 104 and 3.16 × 105mg/kg, respectively, in arsenic-alkali residue. For desulfurized slag and water-quenched slag, the leaching concentration of Sb significantly exceeded the acceptable limits during the leaching tests using the toxicity characteristic leaching procedure and the synthetic precipitation leaching procedure. In addition, As leaching in arsenic-alkali residue was extraordinarily hazardous, being three orders of magnitude higher than the regulatory level of As. According to the results of the extraction tests, all the tested wastes were classified as hazardous waste.     

Molecular diversity of arbuscular mycorrhizal fungi at a large-scale antimony mining area in southern China

Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony (Sb). The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis (PCA) indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis (RDA) showed that Sb contaminationwas the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area.     

Antimony leaching release from brake pads: Effect of pH,temperature and organic acids

Metals from automotive brake pads pollute water, soils and the ambient air. The environmental effect on water of antimony (Sb) contained in brake pads has been largely untested. The content of Sb in one abandoned brake pad reached up to 1.62 × 10⁴ mg/kg. Effects of initial pH, temperature and four organic acids (acetic acid, oxalic acid, citric acid and humic acid) on Sb release from brake pads were studied using batch reactors. Approximately 30% (97 mg/L) of the total Sb contained in the brake pads was released in alkaline aqueous solution and at higher temperature after 30 days of leaching. The organic acids tested restrained Sb release, especially acetic acid and oxalic acid. The pH-dependent concentration change of Sb in aqueous solution was best fitted by a logarithmic function. In addition, Sb contained in topsoil from land where brake pads were discarded (average 9 × 10³ mg/kg) was 3000 times that in uncontaminated soils (2.7 ± 1 mg/kg) in the same areas. Because potentially high amounts of Sb may be released from brake pads, it is important that producers and environmental authorities take precautions.     

The evolution of December 2004 tsunami deposits: Temporal and spatial distribution of potentially toxic metalloids

The article presents the results of research into the content of metalloid fractions in the tsunami deposits from southern Thailand. The following fractions, which are potentially most easily released from deposits to the environment, have been distinguished: the water soluble fraction, the exchangeable fraction extracted with the phosphate buffer and the fraction eluted with the solution of hydrochloric acid. The analytical technique atomic absorption spectrometry with hydride generation was applied. Spatial variability of the metalloid fractions in deposits and changes occurring in deposits over a period of several years of observation were determined. Based on the statistical analysis of the results, an attempt was made to determine the post-depositional release of deposits components to the environment. Based on the conducted research, the 4 years forming process of the arsenic, antimony and selenium occurrence after the deposition of sediments on land were described, as well as the balance in the amount of deposit components released to the environment.     

New best estimates for radionuclide solid–liquid distribution coefficients in soils. Part 3: miscellany of radionuclides (Cd,Co, Ni,Zn, I,Se, Sb,Pu, Am,and others)

New best estimates for the solid–liquid distribution coefficient (K_d) for a set of radionuclides are proposed, based on a selective data search and subsequent calculation of geometric means. The K_d best estimates are calculated for soils grouped according to the texture and organic matter content. For a limited number of radionuclides this is extended to consider soil cofactors affecting soil–radionuclide interaction, such as pH, organic matter content, and radionuclide chemical speciation. Correlations between main soil properties and radionuclide K_d are examined to complete the information derived from the best estimates with a rough prediction of K_d based on soil parameters. Although there are still gaps for many radionuclides, new data from recent studies improve the calculation of K_d best estimates for a number of radionuclides, such as selenium, antimony, and iodine.     

Source-pathway-receptor investigation of the fate of trace elements derived from shotgun pellets discharged in terrestrial ecosystems managed for game shooting

Spent shotgun pellets may contaminate terrestrial ecosystems. We examined the fate of elements originating from shotgun pellets in pasture and woodland ecosystems. Two source-receptor pathways: i) soil-soil pore water-plant and ii) whole earthworm/worm gut contents - washed and unwashed small mammal hair were investigated. Concentrations of Pb and associated contaminants were higher in soils from shot areas than controls. Arsenic and lead concentrations were positively correlated in soils, soil pore water and associated biota. Element concentrations in biota were below statutory levels in all locations. Bioavailability of lead to small mammals, based on concentrations in washed body hair was low. Lead movement from soil water to higher trophic levels was minor compared to lead adsorbed onto body surfaces. Lead was concentrated in earthworm gut and some plants. Results indicate that managed game shooting presents minimal risk in terms of element transfer to soils and their associated biota.     

Recent advances in antimony removal using carbon-based nanomaterials: A review

• The synthesis and physicochemical properties of various CNMs are reviewed. • Sb removal using carbon-based nano-adsorbents and membranes are summarized. • Details on adsorption behavior and mechanisms of Sb uptake by CNMs are discussed. • Challenges and future prospects for rational design of advanced CNMs are provided. Recently, special attention has been deserved to environmental risks of antimony (Sb) element that is of highly physiologic toxicity to human. Conventional coagulation and ion exchange methods for Sb removal are faced with challenges of low efficiency, high cost and secondary pollution. Adsorption based on carbon nanomaterials (CNMs; e.g., carbon nanotubes, graphene, graphene oxide, reduced graphene oxide and their derivatives) may provide effective alternative because the CNMs have high surface area, rich surface chemistry and high stability. In particular, good conductivity makes it possible to create linkage between adsorption and electrochemistry, thereby the synergistic interaction will be expected for enhanced Sb removal. This review article summarizes the state of art on Sb removal using CNMs with the form of nano-adsorbents and/or filtration membranes. In details, procedures of synthesis and functionalization of different forms of CNMs were reviewed. Next, adsorption behavior and the underlying mechanisms toward Sb removal using various CNMs were presented as resulting from a retrospective analysis of literatures. Last, we prospect the needs for mass production and regeneration of CNMs adsorbents using more affordable precursors and objective assessment of environmental impacts in future studies.     

微波高压络合消解石墨炉原子吸收分光光度法测定环境空气中锑

用有机滤膜采集空气中颗粒物样品,用微波高压络合消解后制成样品溶液。用石墨炉原子吸收分光光度法可确定样品溶液中锑的浓度。该方法具有对有机滤膜和样品消解完全,省时,无损失,灵敏度高,准确度、精密度好等特点。     

Mass balance of arsenic and antimony in municipal waste incinerators

The arsenic and antimony balance in two municipal waste incinerators was investigated. Initially, the production rates of ash and wet scrubber effluent were estimated. Then the arsenic and antimony in the ash and wet scrubber effluent were determined, which gave an estimate of the elemental balance. The total amounts of arsenic and antimony in the municipal waste were 0.9 g/t and 30–44 g/t, respectively. The distributions to fly ash were 45–47% and 33–74% for arsenic and antimony, respectively. The distribution mechanisms of arsenic and antimony are discussed from the viewpoints of their thermodynamics as well as their initial valencies, which greatly affect their behaviour. Received: July 2, 1998 / Accepted: February 27, 1999     

Immobilization and transformation of co-existing arsenic and antimony in highly contaminated sediment by nano zero-valent iron

Arsenic(As) and antimony(Sb) are usually coexistent in mine wastes and pose a great threat to human health. The As immobilization by nano zero-valent iron(n ZVI) is promising, however, the stabilization for co-occurring As and Sb is not known. Herein, the immobilization and transformation of As and Sb in n ZVI-treated sediments were evaluated using complementary leaching experiments and characterization techniques. Raw sediment samples from a gold-antimony deposit revealed the co-existence of ul...