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Leaching of copper smelting slag in chloride media was studied. The lixiviants used were aqueous solutions of hydrochloric acid (0.5-2.0 M HCl) as well as hydrogen peroxide and hydrochloric acid (0.5-3.0 M H2O2, 1.0 M HCl). The maximum final copper extraction from the slag of 73% was attained with 3 M H2O2, at room temperature after 120 minutes of reaction. At the same time, 55% of the iron from the slag was also dissolved. The copper extraction increased during the first 60 minutes of reaction and essentially ceased thereafter. Because of a rapid catalytic decomposition of hydrogen peroxide, it should be added continuously to the leach suspension rather than at once at the beginning of the experiment. In fact, it appears that almost complete dissolution of copper from the slag is achievable after about 4 hours of leaching by implementing the method of continuous lixiviant addition. Also, it seems that the final iron extraction could be limited to as low as 20% by using this method.

Phenolic compounds are one of the most important groups of secondary metabolites in plants, with various physiological functions. Their diverse chemical structure and susceptibility to auto-oxidation, and their ability to act as both antioxidants and prooxidants in the presence of metal ions, are some of the main reasons why it is difficult to measure phenolic groups in plant tissues accurately. We present an optimized extraction and hydrolysis procedure which preserves the original chemical structure of phenolics. The presented HPLC method was improved to enable the simultaneous separation and quantification of 39 compounds from different phenolic subclasses (benzoic acids, hydroxycinnamic acids, flavones, flavonols, flavanones, flavanols, isoflavones, anthocyanidins; aglycones and glycosides). Recovery after extraction and complete hydrolysis of glycosides was more than 95% and 84%, respectively. The method was applied to the analysis and comparison of phenolic profiles in the leaves of two species, Ailanthus altissima (Mill.) Swingle and Tilia platyphyllos Scop. from an urban forest park and busy traffic area. The presence of cyanidin glycosides in A. altissima leaves was reported for the first time. Results indicated higher accumulation of phenolics, with two hydroxyl groups in the ortho- position, than flavonoids, with a monohydroxy substitution in the leaves of both species from a busy traffic area.