This contribution deals with the waste from the processes in which raw hide is transformed into leather, as well as with the waste generated during further leather processing and the final waste of leather industry, the worn-out shoes. All this waste, if deposited in the open-air dumps, represents a potential threat to human health, because it contains trivalent chromium (Cr III), which can oxi...

L–Arabinose-based coordination polymers were synthesized by the oxidation of L–arabinose using warm HNO3 to form arabinaric acid and allowing the resulting arabinaric acid to react with the different metal ions such as zinc(II), lead(II), copper(II), iron(III), and chromium(III). Only zinc(II) and lead(II) ions produced crystalline coordination polymers suitable for analysis while copper(II) pr...

Kinetics of Cr(III) ions transport through a bulk liquid membrane containing dinonylnaphthalenesulfonic acid (DNNSA) as a carrier, flowing over aqueous phases, has been examined. Special attention has been paid to the effect of the membrane's velocity flow on the chromium concentration decrease in a feed phase. For the description of relationships of chromium(III) concentration in particular ph...

We have observed both superluminal and ultraslow light propagation in an alexandrite crystal at room temperature. Group velocities as slow as 91 meters per second to as fast as -800 meters per second were measured and attributed to the influence of coherent population oscillations involving chromium ions in either mirror or inversion sites within the crystal lattice. Namely, ions in mirror site...

A chromium-resistant fungus isolated from contaminated air with industrial vapors can be used for reducing toxic Cr(VI) to Cr(III). This study analyzes in vitro reduction of hexavalent chromium using cell free extract(s) of the fungus that was characterized based on optimal temperature, pH, use of electron donors, metal ions and initial Cr(VI) concentration in the reaction mixture. This showed ...

Arthrobacter viscosus biomass was used for Cr(VI) biosorption. The effect of pH on Cr(VI) reduction and removal from aqueous solution was studied in the range of 1-4. The Cr(VI) removal involves both redox reaction and adsorption of metal ions on biomass surface. The removal rate of Cr(VI) was enhanced by very acid conditions, while higher solution pH values favored the removal of total chromiu...

A new indirect method for the determination of iodide and thiosulfate ions in table salt and milk by flame atomic absorption spectrometry was described. This method is based on the reduction of chromium (VI) to chromium(III) with the reducing action of iodide and/or thiosulfate, separation of unreacted Cr(VI) as its 1,5-diphenilcarbazide complex on a column filled with Amberlite XAD-16, elution...

The kinetics of electron transfer between electrochemically passivated chromium and several outer-sphere redox couples have been investigated as a function of passive-film thickness, d = 5 to 25/~, in 1M H2SO4. The apparent rate of electron transfer decreased exponentially with increasing thickness of the passivating overlayer. Similarly, during potentiostatic film growth, the electron-transfer...

Coprecipitation with terbium hydroxide quantitatively recovered trace amounts of chromium(III), copper(II) and lead(II) at pH 8.4 - 10.8, 8.0 - 11.5 and 8.7 - 11.5, respectively. The precipitate was dissolved in 0.85 mol dm(-3) nitric acid, and the analytes were determined by graphite-furnace atomic absorption spectrometry (GF-AAS). The presence of terbium (up to 7 g dm(-3)) did not interfere w...

Background: In light of severe and growing shortages of clean water and the rising environmental pollution in many countries, seawater desalination has been an effective method to produce freshwater. Cationic membranes have enabled environmental scientists to effectively remove toxic heavy metals from wastewater and to regenerate freshwater. Methods: We used a novel method, involving electro- ...