**11. References**


excited states of the atoms adsorbed onto the surface and interacting with their neighbours are to be investigated thoroughly (Vartanyan et al. 2009b). Of prime interest here are such questions as the localization of the electronic excitation on the metal and semiconductor surfaces, their decay times, the pathways and probabilities of the transformation of the electron energy into atomic displacements. Second, photo-induced surface transport is to be studied on a wider range of objects, in particular, those with a metastable structure because in the case the one can expect more pronounced changes (Vartanyan et al. 2010). Finally, practical implementations of photo-induced surface transport may find their way into industry for non-thermal modification of the surfaces at low temperatures (Vartanyan et al.,

This work was supported by the Russian Ministry of Science and Education and Russian

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Bonch-Bruevich, A.M., Vartanyan, T.A., Przhibel'skii, S.G., & Khromov V.V. (1998).

Bonch-Bruevich A.M., Vartanyan T.A., Przhibel'skii S. G., & Khromov V.V. (1999).

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**19** 

*1México 2España* 

**Silver Recovery from** 

*1Universidad de Guanajuato, Guanajuato 2Universidad Autónoma de Madrid, Madrid* 

**Acidic Solutions by Formation of** 

**Ag on Microfiltration Membranes** 

**Nanoparticles and Submicroparticles of** 

Pilar DaSilva2, Pilar Herrasti2 and Mario Avila-Rodriguez1

Pilar González1, F. Javier Recio2, Dario Ribera1, Oswaldo González1,

Despite environmental regulations, wastewaters generated by some industries are in some cases discharged into lakes, rivers or reservoirs after inefficient treatments or without any pretreatment for the elimination or reduction of certain pollutants. Effluents may sometimes contain valuable elements with significant commercial value such as precious metals. Recovery of these metals is important because they could be harmful to aquatic life in lakes

There are legal provisions regarding the composition of an effluent: in the case of liquids containing silver, it is a maximum of 5 ppm. It is known, however, that the silver ion could

Even if silver would not affect health and there were no restrictions to its discharge, there is an important reason to recover it: its value and scarcity. Annual global demand for silver is currently of 24,500 metric tons, used in a vast array of industrial and consumer products. For example, silver is widely used in industrial electroplating as a protective coating or as

A laboratory that uses silver in its production could discharge monthly, a value of 150 to

Worldwide, approximately 57% of the silver present in discarded products is recovered. It has the highest rates of recovery among the most commonly used metals, but much of it is

Various methodologies have been reported for the recovery of this metal ion, with

Among the most common methods for silver recovery are: 1) Metal Replacement; 2) Electrolytic Recovery; 3) Precipitation; 4) Distillation; 5) Ion Exchange and 6) The use of

adornment. Silver reflects light very well, so it is used in car headlights and mirrors.

create a complex especially with thiosulfate, which has little effect on health.

**1. Introduction** 

1,800 dollars in silver.

**Silver recovery** 

and rivers and because of its economic value.

still lost in the various emissions to the environment.

efficiencies that vary depending on the experimental conditions.

