O. Tubertini

CHITIN AND CHITOSAN AS CHROMATOGRAPHIC SUPPORTS AND ADSORBENTS FOR COLLECTION OF METAL IONS FROM ORGANIC AND AQUEOUS SOLUTIONS AND SEA WATER

The rates of adsorption of several metal ions on chitin and chitosan in water and sea-water have been measured; chitin and chitosan are proposed as Chromatographic chelating supports. These natural polymers are also suitable for recovery of trace metals from sea-water.

Separations of trace elements from sea water, brine and sodium and magnesium salt solutions by chromatography on chitosan☆

Abstract Chitosan, a chelating polymer, has been used to collect traces of transition elements from salt solutions and sea water by column chromatography. Chitosan can be favorably compared with the chelating resin Chelex®, and it is proposed as a chelating chromatographic support suitable for pollution detection survey and abatement, for waste water purification and recovery of trace metal ions for analytical purposes.

Radiation induced decomposition of halogenated organic compounds in water

Decomposition by ionizing radiations of p-chlorophenol and tetrachloroethylene in synthetic water samples at about 2 mg Cl L−1, has been studied on laboratory-scale experiments. Bicarbonate/carbonate and nitrate ions, at two concentration levels (20 and 200 mg HCO3−1 and 1 and 50 mg NO3−L−) were added to synthetic samples in order to evaluate their influence on decomposition yield. At 5 kGy γ dose level, a quantitative degradation of p-chlorophenol is obtained whereas only qualitative consideration can be drawn on tetracholoroethylene. Comparative study with respect to degradation of p-cholophenol solutions (about 2 mg Cl L−1) by γ-rays and electron beam irradiation treatment at 0.5 kGy dose level, are in progress; preliminary results indicate that irradiation with γ-rays seems to be more efficient in terms of removal efficiency respect to electron beams source.

Preliminary investigations on7Be as a tracer in the study of environmental processes

The usefulness of cosmogenic7Be as a tracer in a terrestrial environment has been investigated. Atmospheric fluxes and inventories of the radionuclide in grassland have been determined. Environmental behavior in connection with foliar interception and possibility of subsequent release has been studied.

RADIATION RESISTANCE OF CHITIN AND CHITOSAN APPLIED IN THE CHROMATOGRAPHY OF RADIOACTIVE SOLUTIONS

Chitin and chitosan were irradiated in acidic solutions containing a decontaminating soap. It has been shown that these powders suspended in aqueous media do not undergo radiolysis, as their I.R. spectra are not altered, and there is no radiolysis product in the solution, except for the case of nitric acid at lowpH where some chitosan is present in dissolved form. These polymers therefore exhibit very good radiation resistance, in spite of the fact that the monomers undergo very rapid radiolysis.60Co radiations up to 50 000 krad were used. Under these conditions, chitosan does not lose its collection capacity for most of the metal ions of interest in the nuclear field, including cobalt, that can be collected from decontaminating soap solutions with a volume reduction of 10.

Simultaneous Measurements of Remote Lidar Chlorophyll and Surface CO2 Distributions in the Ross Sea.

A comparison between continuous lidar fluorosensor chlorophyll-a measurements and partial pressure of CO2 (pCO2) in surface water is presented. The data were gathered during the XVI Italian Antarctic expedition in the Western Ross Sea and crossing the Southern Ocean. Anticorrelation between CO2 levels and chlorophyll-a determinations was observed throughout the cruise in the late austral summer 2000/01. The survey revealed the presence of high productivity in polynya regions and close to the ice edges. The lidar data, reported here, are consistent with the results of previous campaigns conducted in the same investigated area. The relationship between pCO2 and chlorophyll-a concentration are discussed in terms of biologically driven phenomena responsible for the pCO2 undersaturation with respect to the atmospheric value during the austral summer.

Trace elements distribution in Antarctic sediments by neutron activation analysis

In the present investigation iron and trace elements were determined by instrumental neutron activation analysis in a number of sea bottom sediment samples, collected in the Ross Sea and close to the Italian Station at Terra Nova Bay in Antarctica. Full listing of results is presented and discussed as well as the evaluation of precision and accuracy. In order to find correlations and similarities among the sediment samples, the analytical data were submitted to statistical treatment. In addition rare earth element patterns were obtained. Typical trends were observed with no evident Eu negative anomaly and a depletion of heavy rare earth elements.

Italian Antarctic Research Program: Environmental radioactivity survey around the Italian base (1987–1991) Terra Nova Bay — Ross sea region

Investigations have been carried out by the Italian Antarctic Research Program to determine the natural and artificial radioactivity levels of both the marine and terrestrial environments. Also, natural and anthropogenic fluxes of aerosol particles onto the Antarctic surface have been examined.

Purification of thallium(I) nitrate by column chromatography on chitosan

SummaryChitosan powder has been used in column chromatography for the fast separation of cadmium, mercury, iron and other metals from 1mM and 38mM solutions of thallium(I) nitrate. Thallium is recovered with water, and other ions have been selectively eluted with complexing agents.ZusammenfassungChitosanpulver wurde zur raschen, säulenchromatographischen Abtrennung von Cd, Hg, Fe und anderen Metallen aus 10−3-rn bzw. 3,8·10−2-m Lösungen von Thallium(I)-nitrat verwendet. Thallium wird mit Wasser, die anderen Ionen werden selektiv mit Komplexbildnern aus der Chitosansäule eluiert.

Distribution of 226Ra in the Ross Sea—Antarctica

Abstract An improved procedure for the determination of 222Rn and 226Ra in seawater developed for easier on-board operations is presented. Data on the radioactive disequilibrium between the mentioned radionuclides as directly determined in the field can be greatly helpful in the study of the gas-exchange processes at the air-sea interface, especially as far as the Antarctic Ocean is concerned. The method employed has been preliminarly tested in laboratory on a set of seawater samples collected in the Ross Sea and 226Ra data collected are discussed and compared to literature data.