Chemical and textural controls on the formation of sepiolite, palygorskite and dolomite in volcanic soils

Geoderma ◽  
2016 ◽  
Vol 271 ◽  
pp. 99-114 ◽  
Author(s):  
Javier Cuadros ◽  
Jose L. Diaz-Hernandez ◽  
Antonio Sanchez-Navas ◽  
Antonio Garcia-Casco ◽  
Jorge Yepes
Keyword(s):  
Volcanic Soils

scholarly journals Sorption and Desorption of Vanadate, Arsenate and Chromate by Two Volcanic Soils of Equatorial Africa

Soil Systems ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 22
Author(s):  
Sara Gonzalez-Rodriguez ◽  
Maria Luisa Fernandez-Marcos
Keyword(s):  
Laboratory Experiments ◽  
Sorption Isotherms ◽  
Soil Samples ◽  
Mineral Surfaces ◽  
Volcanic Soils ◽  
Iron Species ◽  
Freundlich Model ◽  
Equatorial Africa ◽  
Relevant Role ◽  
Icp Mass Spectrometry

Sorption of oxyanions by soils and mineral surfaces is of interest due to their role as nutrients or pollutants. Volcanic soils are variable charge soils, rich in active forms of aluminum and iron, and capable of sorbing anions. Sorption and desorption of vanadate, arsenate, and chromate by two African andosols was studied in laboratory experiments. Sorption isotherms were determined by equilibrating at 293 K soil samples with oxyanion solutions of concentrations between 0 and 100 mg L−1 V, As, or Cr, equivalent to 0−2.0 mmol V L−1, 0−1.3 mmol As L−1, and 0−1.9 mmol Cr L−1, in NaNO3; V, As, or Cr were determined by ICP-mass spectrometry in the equilibrium solution. After sorption, the soil samples were equilibrated with 0.02 M NaNO3 to study desorption. The isotherms were adjusted to mathematical models. After desorption with NaNO3, desorption experiments were carried out with a 1 mM phosphate. The sorption of vanadate and arsenate was greater than 90% of the amount added, while the chromate sorption was much lower (19–97%). The sorption by the Silandic Andosol is attributed to non-crystalline Fe and Al, while in the Vitric Andosol, crystalline iron species play a relevant role. The V and Cr sorption isotherms fitted to the Freundlich model, while the As sorption isotherms conformed to the Temkin model. For the highest concentrations of oxyanions in the equilibrating solution, the sorbed concentrations were 37–38 mmol V kg−1, 25 mmol As kg−1, and 7.2–8.8 mmol Cr kg−1. The desorption was low for V and As and high for Cr. The comparison of the sorption and desorption isotherms reveals a pronounced hysteresis for V in both andosols and for Cr in the Silandic Andosol. Phosphate induced almost no V desorption, moderate As desorption, and considerable Cr desorption.

Materials to cyanobacterial and algal flora from volcanic soils of Shiveluch volcano

2021 ◽  
pp. 135-138
Author(s):  
Rezeda Z. Allaguvatova ◽  
Veronika B. Bagmet ◽  
Arthur Yu. v Nikulin ◽  
Shamil R. Abdullin ◽  
Andrey A. Gontcharo
Keyword(s):  
Species Composition ◽  
Kamchatka Peninsula ◽  
Algal Flora ◽  
Volcanic Soils ◽  
Shiveluch Volcano ◽  
Nitzschia Palea ◽  
Terrestrial Cyanobacteria ◽  
Composition Study ◽  
Cyanobacteria And Algae ◽  
Tetradesmus Obliquus

During the species composition study of terrestrial cyanobacteria and algae from volcanic soils of Shiveluch Volcano (Kamchatka peninsula, Russia) eighteen taxa from five phyla were revealed: Cyanobacteria – 4, Bacillariophyta – 4, Ochrophyta – 2 (Eustigmatophyceae – 1, Xanthophyceae – 1), Charophyta – 1, Chlorophyta – 7 (Chlorophyceae – 2, Trebouxiophyceae – 5). Nitzschia communis Rabenhorst, Nitzschia palea (Kützing) W. Smith, Eolimna minima (Grunow) Lange-Bertalot, Eremochloris sp., Tetradesmus obliquus (Turpin) M.J. Wynne, Nostoc edaphicum Kondratyeva were most frequency.

Natural nanoclays: applications and future trends – a Chilean perspective

Clay Minerals ◽  
2009 ◽  
Vol 44 (2) ◽  
pp. 161-176 ◽  
Author(s):  
M. Calabi Floody ◽  
B. K. G. Theng ◽  
P. Reyes ◽  
M. L. Mora
Keyword(s):  
Agricultural Land ◽  
Clay Fraction ◽  
Barrier Properties ◽  
Clay Nanocomposites ◽  
Volcanic Soils ◽  
Gas Barrier ◽  
Important Species ◽  
The Past ◽  
Organically Modified ◽  
Water And Wastewater

AbstractBecause of their large potential for agricultural, industrial and medicinal applications, nanomaterials have been the focus of much research during the past few decades. Nanoclays are natural nanomaterials that occur in the clay fraction of soil, among which montmorillonite and allophane are the most important species. Montmorillonite is a crystalline hydrous phyllosilicate (layer silicate). Organically-modified montmorillonites or ‘organoclays’, formed by intercalation of quaternary ammonium cations, have long been used as rheological modifiers and additives in paints, inks, greases and cosmetics and as carriers and delivery systems for the controlled release of drugs. Perhaps the largest single usage of organoclays over recent years has been in the manufacture of polymer-clay nanocomposites. These organic–inorganic hybrid materials show superior mechanical, thermal and gas-barrier properties. Organoclays are also useful in pollution control and water treatment. Allophane is a non-crystalline aluminosilicate derived from the weathering of volcanic ash. A large proportion of the agricultural land in Chile is covered by volcanic soils,the clay fraction of which is dominated by allophane. Consisting of nanosize (3.5–5.0 nm) hollow spherules, allophane is a suitable support material for enzyme immobilization. Allophane is also effective at adsorbing phenolic compounds and colour from kraft mill effluents and phosphate from water and wastewater.

scholarly journals Fungal diversity in high Andean ecuadorian forest soil

2021 ◽  
Author(s):  
Adrian Valdez ◽  
Sergio Covarrubias
Keyword(s):  
Fungal Diversity ◽  
High Performance ◽  
Its Region ◽  
Taxonomic Composition ◽  
Soil Samples ◽  
Fungal Communities ◽  
Gallery Forest ◽  
Volcanic Soils ◽  
Altitudinal Gradients ◽  
The Andes

The Andes range in Ecuador presents high biodiversity and characteristic altitudinal gradients, which are frequently threatened by deforestation and farming. In particular, forest have developed in the high inter-Andean alley on volcanic soils forming a unique ecoregion. Little is known on the fungal biodiversity of soil in such high Andean gallery forest submitted to strong degradation pressures. Therefore, in this study we evaluated wether the soil mycobiome was associated with altitudinal gradients during the dry season. Three representative locations were selected based on altitude: A (3,309 meters above the sea level, masl), B (3,809 masl) and C (4,409 masl). High performance sequencing (NGS) of the ITS region of ribosomal DNA genes with Illumina technology was used to explore the fungal taxonomic composition in the soil samples. Our results showed changes in the structure of fungal communities in the different locations, related to the relative abundance of Amplicon Sequence Variants (ASV). Higher fungal diversity was related with the altitudinal gradient with average taxa ranging from 675, 626 and 556 ASVs, respectively from location A to C. The results highlight the complexity and diversity of fungal communities in high Andean forest and the need to protect these unique mycobiomes. The findings in this ecosystem of Ecuador will improve our understanding of distribution, diversity, ecology, and biological perspectives for the restoration of terrestrial microbiomes.

Geochemical specificity of volcanic soils of Kamchatka

2010 ◽  
Vol 43 (4) ◽  
pp. 380-389 ◽  
Author(s):  
L. V. Zakharikhina ◽  
Yu. S. Litvinenko
Keyword(s):  
Volcanic Soils

Multivariate statistical analysis of chemical properties of European volcanic soils

2007 ◽  
pp. 387-400 ◽  
Author(s):  
A. Martínez-Cortizas ◽  
J. C. Nóvoa ◽  
X. Pontevedra ◽  
T. Taboada ◽  
E. García-Rodeja ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Multivariate Statistical Analysis ◽  
Chemical Properties ◽  
Volcanic Soils ◽  
Multivariate Statistical
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