Innovative Biomining: metal recovery from valuable residues

DONATI EDGARDO; CASTRO CAMILA

Heavy Metals in the Environment: Microorganisms and Bioremediation

CRC Press

Año: 2018; p. 121 - 132

Metals are useful for several and different purposes; they have industrial applications and also they are present in multiples devices in the daily life (Donati et al., 2016). Nowadays, metal-bearing residues are being produced in huge amounts and this quantity is increasing due to increase in population as well as the diversification of the applications of metals. For example, in the case of copper, even when it has been partially displaced for new engineering materials in some applications, the current production is 40-fold higher than it was a century ago although the world?s population only increased from 1 to about 7 billion in the same period of time (Donati et al., 2016). Numerous industries, for instance, electroplating, metal-finishing, electronic, steel and nonferrous processes, petrochemical and pharmaceutical, and the used electronic/household goods discharge a variety of heavy metals such as Zn, Cd, Cr, Cu, Ni, Pb, V, Mo, Co, etc. (Lee and Pandey, 2012). Atmospheric deposition is a major mechanism for metal input in terrestrial ecosystems. Unlike organic compounds which in general are easy to degrade, heavy metals cannot be decomposed. Metals have different reactivity and toxicity based on the nature of particular metal, concentration and speciation. In the present scenario, heavy metal pollution is a serious concern due to their harmful nature especially when they meet or exceeded the regulatory limits. An inadequate disposal of metal-bearing residues could cause serious problems because this kind of hazardous waste contaminates the sites and 161often degrades surroundings of human habitation including air, surface, and ground water if not treated properly. In contrast, these kinds of wastes contain valuable metals, precious metals, and rare elements in quantities even higher than some ores. The application of a suitable extraction process to recover some of the metals present in these wastes may be an appropriate approach to mitigate their toxicity.