Selective adsorption of metallic complex using polyaniline or polypyrrole

The preparation of composites of cellulose acetate, triphenyl phosphate and poly (acrylic acid) (M), coated with polyaniline (M-PAni) or polypyrrole (M-PPy), including tests of the adsorptivity of complexes of copper-iodide, are presented in this work. Characterization of M-PAni and M-PPy by FT-IR and TGA before and after being exposed to natural weathering conditions are done to study the effects that environmental conditions have on them. In solutions with Cu only, the M-PAni presented 51.6% Cu adsorption and M-PPy presented 10.7%. SEM analysis, EDS, XPS and ATR-FTIR of M-PAni and M-PPy before and after of Cu adsorption are included. In the presence of gold-iodide complex, M-PAni shows 47.4% Cu adsorption, six times higher than the M-PPy, 7.2%; this result is attributed to better interaction between the PAni and the copper-iodide complex than PPy and the copper-iodide. The adsorption equilibrium data of copper-iodide complex fits the Langmuir isotherm model for both M-PAni and M-PPy, suggesting the formation of an adsorbed monolayer. Desorption process for Au is more effective in the two materials, 34.1% with M-PAni and 86.6% with M-PPy, than for Cu with 1.0% and 2.6% respectively. The present method, which uses iodide as a single leaching agent for Au and Cu and M-PAni and M-PPy as adsorbents is recommended. These composites are suitable selective materials. Mechanism of adsorption of Cu(I)2−. This schematic drawing shows the mechanism of ion exchange of Cu(I)2− with the conducting polymers. The Cu(I)2− complex displaces the dopant anion (Cl−), thus remaining adsorbed on the composite. The adsorption of Cu(I)2− is more feasible with the PAni found in the M-PAni composite than with the PPy of the M-PPy composite. [Display omitted] •The preparation of (M) composites, coated with PAni or PPy was performed.•The composites present good environmental stability.•M-PAni is an effective adsorbent for the recovery of a metallic complex of copper.•M-PPy is a selective material recommended for the recovery of gold, not for copper.•Both composites obey the Langmuir isotherm model, a monolayer adsorption process.