Behaviour of non-standard composition copper bearing anodes from the copper refining process.

This paper addresses on investigation the possibility of electrolytic treatment the sulphur acidic waste solution, obtained in the conventional electrolytic copper refining process. Beside the high copper concentration, the high concentration of other metals, in this case nickel, is the main characteristic of these waste solutions. Due to this fact, the copper bearing anodes with non-standard nickel, lead, tin and antimony content were specially prepared for the refining process. Nickel content of all anodes was approximately 7.5 mass%, and the content of lead, tin and antimony was varied. The preliminary results, obtained using the standard electrochemical techniques, have indicated that the copper bearing anodes could be used under the same conditions as well as in the conventional copper refining process. The measurements in constant galvanostatic pulse have pointed out that the all chemical elements from copper bearing anodes were dissolved and only copper was deposited onto the cathode. It was also pointed out that Ni concentration in the base working electrolyte (sulphur acidic waste solution), after 72 h of process, increased to 102 mass% at T(1)=63+/-2 degrees C and up to 122 mass% at T(1)=73+/-2 degrees C, while arsenic concentration decreased to a minimum value.

Morphological changes of poly(DI-lactide-co-glycolide) nano-particles containing ascorbic acid during in vitro degradation process.

Poly(DL-lactide-co-glycolide) powder composed of uniform particles with the mean particle size in the range of 110-170 nm was obtained from commercial granules. Ascorbic acid in different concentrations was encapsulated into the poly(DL-lactide-co-glycolide) particles. Degradation of the latter in terms of morphological changes in the physiological solution was followed. Within a period of 2 months, the particles completely degrade and all the ascorbic acid is released. The samples were characterized by ultraviolet spectroscopy and scanning electron microscopy.

Stereological analysis of the poly-(DL-lactide-co-glycolide) submicron sphere prepared by solvent/non-solvent chemical methods and centrifugal processing.

Fine particles made of poly(lactide-co-glycolide) (DLPLG) are excellent candidates for controlled release of delivering drugs and genes, because of their degradable nature. The preparation of DLPLG submicron spheres poses serious challenges that are not necessarily present when preparing macroparticles. In the present paper, DLPLG powder is produced with chemical method using solvent/non-solvent systems with subsequent centrifugation of the solution. The samples were characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM) and stereological analysis. By changing the aging time with non-solvent and time and velocity of the centrifugal processing, it is possible to influence on the morphology and uniformity of the copolymer particles. Powder of the series with short aging time with non-solvent and longest time and velocity of the centrifugal processing has smallest particles and highest uniformity, where mean particles sizes were between 150 nm and 230 nm depending on which stereological parameters are considered (D(max), maximal diameters, feret X or feret Y).