DETERMINATION OF THE TOXIC TRACE ELEMENT CONTENT OF INDUSTRIAL WASTES BY X~RAY FLUORESCENCE ANALYSIS WITH ISOTOPE EXCITATION. INVESTIGATION OF PAINT WASTES

The concentration of the metal components of wastes originating from paints used in various fields was determined, with particular regard to toxic elements. It was established on the basis of measuring results that wastes generally contain more than one toxic element in different quantities. These elements reveal different mobilities in media of different pH, so that the probability of their getting into the environment considerably varies for the single elements. The deposition of wastes of this type on the soil can be considered as safe. if the migration of the toxic elements is reduced to a minimum

Energetics of ion selectivity in slit-like pores

We study the effect of the charge and/or size asymmetry, we show results for a wide range of electrode charge and we study the effect of charge and size asymmetry on the electrode potential, and the competition of two cations of different size and valence near a highly charged electrode. If the ions have different diameters and/or valences, the electrode potential is nonzero even if the electrode charge is zero (PZC potential). Size and valence asymmetries are two competing effects regarding the sign and magnitude of the PZC potential

The Behavior of 2:1 and 3:1 Electrolytes at Polarizable Interfaces

The behavior of the electrical double layer (DL) is known to be different at polarizable interfaces, specifically, at a metallic electrode (where the dielectric constant of the electrode is infinitely large, ε1 → ∞) and at an air/electrolyte interface (where the dielectric constant of the electrode is ε1 = 1) than is the case for unpolarized interfaces. For the polarized interface, if multivalent ions are present, these ions are attracted/repelled more than is the case for monovalent ions. Therefore, the divalent/trivalent ions (assumed to be cations to be specific) accumulate near the metallic electrode more than for the unpolarized electrode and a charge inversion occurs. In such asymmetric electrolytes, this results in a large potential at zero electrode charge. The behavior is reversed for the air/electrolyte interface. This is more pronounced at low reduced temperatures (or, equivalently, at high ionic couplings). The anomalous capacitance behavior of the DL is seen for the unpolarized electrode, where the temperature derivative of the capacitance is positive at low reduced temperatures (characteristic of electrolytes with ions with high ionic couplings or molten salt DLs at room temperatures) while it is negative at high reduced temperatures (characteristic or aqueous solutions of monovalent salts at room temperatures). At least for the states we consider, this anomalous behavior is enhanced for the air/electrolyte interface but vanishes for a metallic electrode. Our Monte Carlo simulations of these phenomena are reported