Spectroscopic and Microscopic Characterization of Volcanic Ash from Puyehue-(Chile) Eruption: Preliminary Approach for the Application in the Arsenic Removal

Irma Lia Botto,Delia Gazzoli,María José González,María Elena Canafoglia

doi:10.1155/2013/254517

Abstract

Volcanic ash from Puyehue Cordon Caulle Volcanic Complex (Chile), emitted on June 4, 2011, and deposited in Villa La Angostura at ~40 km of the source, was collected and analyzed by Raman spectroscopy, optical and scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), surface area (BET), and chemical analysis (ICP-AES-MS technique). The mineralogical and physicochemical study revealed that the pyroclastic mixture contains iron oxides in the form of magnetite and hematite as well as pyroxene and plagioclase mineral species and amorphous pumiceous shards. Carbonaceous material was also identified. Physicochemical techniques allow us to select two representative samples (average composition and Fe-rich materials) which were used to analyze their performances in the adsorption process to remove arsenic from water. Additional iron activation by means of ferric salts was performed under original sample. Results showed that the low-cost feedstock exhibited a good adsorption capacity to remove the contaminant, depending on the iron content and the water pH.

Highlights

The south-andes Cordillera is one of the world regions with intense volcanic and tectonic activity
The mineralogical and physicochemical study revealed that the pyroclastic mixture contains iron oxides in the form of magnetite and hematite as well as pyroxene and plagioclase mineral species and amorphous pumiceous shards
Physicochemical techniques allow us to select two representative samples which were used to analyze their performances in the adsorption process to remove arsenic from water

Summary

Introduction

The south-andes Cordillera is one of the world regions with intense volcanic and tectonic activity. The last eruption, started on June 4, 2011, was associated with the activity of Puyehue Cordon Caulle Volcanic Complex (PCCVC), Chile, located at 40∘34󸀠57󸀠󸀠S-72∘06󸀠53󸀠󸀠W, emitting more than 5 × 106 m3 of pyroclastic material [1]. The preliminary characterization of the ash showed a composition predominantly rhyolitic, the ejected material was composed of different types of particles. Eruption stages and distance from the volcanic source affected the chemical composition of the mixture, but, in general, the material was nearly amorphous to the XRD, with a texture characterized by the presence of vesicles. In the early stages of the volcanic event a dark (brownish-black) and heavy particulate matter, with variable size and hardness, was emitted [2]

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