Recovery of platinum laboratory rejects: A simple, economic and high-performance alternative

Abstract

In this work, the waste processing from platinum laboratories is proposed as an alternative to minimize discard in the environment and to get precursor inorganic substances with high levels of purity and yield. The residues were divided into three groups, where group (A) consisted of aqueous residues, group (B) was obtained from of solid residues of reactions, and group (C) consisted of residues containing organic solvents. All residues were recovered through evaporation, incineration and calcinations processes, resulting in platinum oxides. In possession of the platinum oxides, they were subjected to a reduction for obtain metallic platinum, which was treated with aqua regia and potassium chloride to obtain of the potassium hexachloroplatinate. After the characterization of this complex via X-ray diffractometry, a controlled reduction was performed with the need to obtain the potassium tetrachloroplatinate. This last complex was characterized by X-ray diffraction, electronic absorption spectroscopy and 195Pt nuclear magnetic resonance. All characterizations confirmed the formation of the platinum complexes (IV and II). Potassium tetrachloroplatinate was produced with high reaction yield (> 98 %), purity and crystallinity. The methodology proposed here presents excellent results in the waste recovery, thus contributing to the not discard of harmful substances in the environment.