**3. Results and discussion**

442 Mass Transfer - Advanced Aspects

nanoparticles depends on different parameters such as, silver, nitric and ascorbic acids concentrations and the stirring rate of the solutions. Considering the extensive applications of nano and submicrometer Ag particles as catalysts, conductive adhesives, display devices, passive components, inkjet printing, photon emission, and higher order multiples resonances substrates (Dai et al., 2011; Hu et al., 2010; Xu et al. 2008; Sung et al., 2010; Gloskowskii et al.,

All products used had analytical grade and were used as received. The device used for this work is shown in Figure 1 and comprises a two-compartment cell, divided by a

Fig. 1. Cell used for the recovering of silver, the membrane is located in between the two

The feed phase was composed by different concentrations of AgNO3 (from 25 to 100 mg L-1) at various HNO3 concentrations (from 0.1 to 1 mol L-1). The stripping phase was composed by a solution of ascorbic acid and its concentrations were changed from 0.2 to 1.5 mol L-1. The feed and stripping solutions were added to compartments 1 and 2, respectively. The cell was then covered and the system was stirred. Aliquots were taken from both sides at several different times and, finally; Ag (I) content was analyzed by atomic flame absorption using a Perkin-Elmer Analyst 200 flame atomic absorption spectrometer. The pH of both the feed and stripping solutions was measured with the help of a combined glass electrode using a Methrom potentiometer (Titrino 716). The ascorbic acid's quantitative determination in both compartments was performed by Iodometry using a standard solution of iodine and starch

The microporous membrane used, was a polyvinylidene difluoride (PVDF) hydrophilic membrane with 75% porosity, 125 µm thickness and average pore size of 0.22 µm (Millipore). During reduction of the silver ions, the membrane is used as a support for the

2008), this methodology could be used in a wide range of industrial applications.

**2. Experimental** 

compartments

as an indicator of endpoint.

metallic silver formations.

microfiltration membrane.

**2.1 Methodology for the transference of Ag (I)** 
