Chromium VI issue in leather waste - A technology for the processing of used leather goods and potential of raman spectroscopy in chromium traces detection

Abstract

In this paper, the authors deal with the problem of chromium present in various products and materials, and the health and environmental risks that this chromium can represent if uncontrolled. Special emphasis is given to various chrome tanned wastes generated by the leather industry. The agent that makes this waste potentially hazardous is hexavalent chromium. Its compounds can have negative effects on human health and some chromium VI salts are considered carcinogens. The authors present the risks of spontaneous oxidation of trivalent chromium to its hexavalent form in various conditions, as well as an analytical method for detection of small concentrations of both forms of chromium using Raman spectroscopy. Raman spectra of hexavalent chromium and simultaneous detection of the two valences of chromium obtained from leather samples are presented. Another important issue addressed in this paper are technologies processing various kinds of chrome-tanned waste. From the technological point of view, there are several ways of handling primary leather waste, but no satisfactory technology has been developed so far for the secondary waste (manipulation waste, e.g. leather scraps, and used leather products). An innovative hybrid technology of processing the secondary waste is presented and tested in industrial conditions and its application on used leather goods is discussed, as well as possibilities of commercial utilization of the products generated by the technology.