A New Approach to the Understanding of the Mechanism of Lead Electrodeposition

The most important applications of lead include the production of high purity active materials for acid battery, for semiconductors, and for the fabrication of electrochromic devices. In the form of powder, lead is widely used in industries of gas and oil exploration, radiological medical protective clothing, as an industrial X-ray shield, golf club manufacture, and antifriction products. The electrodeposition technique is a very suitable way to obtain lead in the form suitable for the application in the above-mentioned technologies. For example, the advantage of use of electrodeposition technique in the production of lead in the powder form lies in the fact that lead powder is produced at low overpotentials and hence with small spent of energy. The open porous structures of lead with the extremely high surface area (the honeycomb-like ones), which are ideally situated for electrodes in electrochemical devices such as fuel cells, batteries, and sensors, are also possible to get by the electrodeposition techniques

Bioremediation of industrial effluents containing heavy metals using brewing cells of Saccharomyces cerevisiae as a green technology : a review

The release of heavy metals into the environment, mainly as a consequence of anthropogenic activities, constitutes a worldwide environmental pollution problem. Unlike organic pollutants, heavy metals are not degraded and remain indefinitely in the ecosystem, which poses a different kind of challenge for remediation. It seems that the "best treatment technologies" available may not be completely effective for metal removal or can be expensive; therefore, new methodologies have been proposed for the detoxification of metal-bearing wastewaters. The present work reviews and discusses the advantages of using brewing yeast cells of Saccharomyces cerevisiae in the detoxification of effluents containing heavy metals. The current knowledge of the mechanisms of metal removal by yeast biomass is presented. The use of live or dead biomass and the influence of biomass inactivation on the metal accumulation characteristics are outlined. The role of chemical speciation for predicting and optimising the efficiency of metal removal is highlighted. The problem of biomass separation, after treatment of the effluents, and the use of flocculent characteristics, as an alternative process of cell-liquid separation, are also discussed. The use of yeast cells in the treatment of real effluents to bridge the gap between fundamental and applied studies is presented and updated. The convenient management of the contaminated biomass and the advantages of the selective recovery of heavy metals in the development of a closed cycle without residues (green technology) are critically reviewed.The authors thank to the Fundacao para a Ciencia e a Tecnologia (FCT) from Portuguese Government for the financial support of this work with FEDER founds, by the Project POCTI/CTA/47875/2002 and through the grants PEST-OE/EQB/LA0023/2011 (IBB) and PEST-C/EQB/LA0006/2011 (REQUIMTE)