Performance of Polyaniline Coatings on Stainless Steel for Silver Recovery

Abstract

In this study, conducting polymer films were synthesised by electrochemical polymerisation of aniline on the stainless steel substrates, and such films were employed for the process of electroless precipitation of silver. The electropolymerisation mode and conditions were carefully selected to provide films displaying structure and electroactivity appropriate to the process. The influence on the metal recovery efficiency of the both PANI surface area and electrolyte composition was also analysed.

The heterogeneous growth of P(3MeTh)—an ellipsometric study

“…The results from monitoring the evolution of the polymer film optical parameters have also given sound indications on structural modifications upon thickening [13] which have been further supported by atomic force microscopy investigations [14].…”

“…This approach does not reveal the step in the film optical density (previously reported [12,13]) but gives a reasonable basis to assume that on the top of a first compact uniform film, the electropolymerisation process may involve, e.g. for growth charges higher than 20 mC cm − 2 (E g =1.56 V) the formation of a second layer displaying different properties.…”

Metallic‐Based Nanocomposites of Conductive Polymers

“…Most of the studies in this field concern the deposition of noble metals Au [16,[210][211][212][213][214][215][216][217][218][219][220][221][222], Ag [223][224][225][226][227][228][229][230][231][232][233][234][235], Pd [156,158,[236][237][238][239][240][241][242][243][244][245][246][247][248], Pt [249,250] and Hg [251,252], with equilibrium potentials that are positive enough with respect to the potentials of oxidation transitions in most CPs, e.g. PANI, PPY etc.…”

“…the self-established electrical potential of the bulk CP. Measurement of this quantity in the course of CP-driven metal deposition shows a gradual shift of the CP state from lower to higher oxidation state [163,226,232,248] and indicates clearly the timescale of substantial changes in the driving force of the process (Figure 7.9). It is known that the nucleation of metal particles may occur as an instantaneous (at high supersaturations) or a progressive (at low supersaturations) process.…”

“…PANI or PPY) Later investigations [217] have shown the occurrence of this process in neutral solutions and also for polymers of the thiophene type that are not expected to undergo protonation/deprotonation reactions. The self-sustained metal-deposition process has been suggested as tool for recovery of precious metals from waste solutions by using CP powders, membranes, supported layers, coated fabrics, or reticulated vitreous carbon (RVC) [210][211][212]225,226,236,253]. However, very long-term exposure to the metal-ioncontaining solution may result in degradation (decrease in electrical conductivity and gradual loss of material) of the CP layer, as evidenced with the exposure of PANI to chloraureate solution [213].…”