Search results for " sequential extraction"
showing 4 items of 4 documents
Experimental Investigation into the Effect of Pyrolysis on Chemical Forms of Heavy Metals in Sewage Sludge Biochar (SSB), with Brief Ecological Risk …
2021
Experimental investigations were carried out to study the effect of pyrolysis temperature on the characteristics, structure and total heavy metal contents of sewage sludge biochar (SSB). The changes in chemical forms of the heavy metals (Zn, Cu, Cr, Ni, Pb and Cd) caused by pyrolysis were analyzed, and the potential ecological risk of heavy metals in biochar (SSB) was evaluated. The conversion of sewage sludge into biochar by pyrolysis reduced the H/C and O/C ratios considerably, resulting in stronger carbonization and a higher degree of aromatic condensation in biochar. Measurement results showed that the pH and specific surface area of biochar increased as the pyrolysis temperature increa…
Iron isotope signature of magnetofossils and oceanic biogeochemical changes through the Middle Eocene Climatic Optimum.
2021
21 pages; International audience; Magnetotactic bacteria (MTB) intracellularly precipitate magnetite (Fe3O4) crystals that can be preserved in the geological record. When MTB die, the so-called magnetofossils constitute valuable proxies for paleoenvironmental reconstructions and are suspected to represent some of the oldest traces of biomineralization on Earth. Yet, the biogenicity of putative magnetofossils found in ancient terrestrial and extra-terrestrial samples is still largely debated and their significance for past climate still holds uncertainties. Here we studied a sedimentary sequence from the Indian Ocean (ODP Hole 711A) recording the Middle Eocene Climatic Optimum (MECO) through…
Metals distribution in the organic and inorganic fractions of soil: A case study on soils from Sicily
2005
The content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, has been determined in the organic and inorganic fraction of eight soil samples from Sicily. A modified type-Tessier sequential extraction procedure has been used to recognize metals in five different fractions categorised as follows: (a) exchangeable metals, (b) metals bound to carbonates, (c) metals bound to iron and manganese oxides, (d) metals bound to organic matter, and (e) metals in residual fraction. The mineralogical composition of soils samples was characterized by X-ray diffraction. Humic substances were extracted by means of an alkaline extraction procedure. It has been found that both the mineralogical composition and the di…
Application of ICP-MS for measuring soil metal cations from sequential extraction
2005
The present work is part of a collaboration between Palermo and Seville Universities to investigate the cations incorporated into calcite and its effect in the trace metal mobility in soils. The study area is located in the central part of Sicily. Calcite is usually greatly dispersed and has a major influence on the pH of soils and therefore on trace element behaviour. A great affinity for carbonates has been observed for a wide range of cations incorporated into calcite. in order to investigate the metal cations in soil carbonate, 1M MgCl2 was used to remove the exchangeable Ca. Sub-samples were treated with acid acetic 1M to quantify the total amount of Ca and metal cations in soil carbon…