engleski

Nanosized mineral phases in marine sediments of the Eastern Adriatic Coast: separation and characterization

In this preliminary report, for the first time, the mineralogical and physico-chemical characteristics of nanosized mineral phases separated from different marine environments of the Eastern Adriatic Coast are presented. These sediments were collected from the Neretva Channel (Croatia), the Bay of Kotor (Montenegro), and from the open sea in front of the mouth of the Bojana River (Albania). An innovative separation process, achieved through various physical and chemical treatments, was developed and used to obtain the nanosized mineral phases. The morphological and structural characteristics of the separated sediment fractions were examined by field-emission scanning microscopy (FEG-SEM) and X-ray diffraction (XRD) ; the particle size was measured by laser diffraction (LD) ; the specific surface area (SSA) was determined using the single-point nitrogen-adsorption technique and the cation- exchange capacity (CEC) was measured using an ammonia exchange and ammonia-specific electrode. The obtained results showed that the morphological features and the structural characteristics of the submicron-sized mineral phases encountered in the investigated sediments mainly belong to a specific group of layered-type hydrous aluminosilicates (clay minerals), which are characterized by a large specific surface area and high cation- exchange capacities. The river-dominated discharges of the suspended terrestrial particulates into the marine environment were found to be the main source of submicron-sized colloidal materials. The significant differences in their composition reflect the diversity of the studied sedimentological systems and catchment areas. This study endeavours to provide new evidence that should help us to understand the processes involved in the transport and deposition of nanosized mineral phases, and their role in the conveyance of organic and inorganic compounds in the Adriatic marine environments.

nanosized mineral phases; sediments; Adriatic Sea

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