Poly(3-methyltiophene)- Multi Walled Carbon Nanotubes Composite Electrodes

Our goal, is focalized in the synthesis of composite film electrodes used in the detection of contaminants from water. Films of poly(3-methylthiophene) (P3MT) were prepared by electropolymerization over glassy carbon electrode (ϕ= 3 mm) and then impregnated with a thin dispersion of multi wall–carbon nanotubes, (MWCNT). Also, the MWCNT was directly embedded over the glassy carbon electrode. These composite materials P3MT/MWCNT and MWCNT coated onto a glassy carbon electrode (GC) are applied in electrochemical As(III) detection with different supporting electrolytes. The cyclic voltammetry of MWCNT/GC modified electrode in NaNO3 or Na2SO4 0.1 molL-1 showed As(III) irreversible anodic wave occurring at 0.9 to 1.3 V vs Ag/AgCl range, and lineal conduct up to 5-10 mmol L-1 As(III), and even reproducible results after it had been used for several times at highest concentrations. The alkaline Na2HPO4 solution improved the response and resolution this electrode with anodic wave at 1.1 V vs Ag/AgCl. Performance of modified P3MT/MWCNT/GC electrode, by anodic stripping voltammetry (ASV) in 0.1 mol L-1 Na2HPO4 (pH 10) solution was notable, because the low potential 0.55 V vs Ag/AgCl by As(III) anodic current peak. The electrolysis of As(III) at constant potential with MWCNT/felt carbon electrode (ϕ = 8 mm) produced a 94% of less toxic As(V) form, which was recovered by liquid phase retention-assisted by polymers (LPR-P) method.