Surfactant Modified ZSM-5 Nanozeolite in the Modification of Carbon Paste Electrode for Voltammetric Determination of Sulfide

Carbon paste electrode was modified by surfactant modified ZSM-5 nanozeolite and the electrochemical behavior of this modified electrode was studied using cyclic voltammetry. This electrode showed enhanced electrochemical response and strong analytical activity towards the direct electrochemical oxidation of sulfide. The influence of some parameters such as different mass ratio of ZSM-5 nanozeolite and graphite, surfactant concentration, pH and scan rate of potential was investigated on the anodic peak height of the sulfide oxidation. Under optimal conditions in a buffer solution, pH 8.0, the anodic peak currents increased linearly with the concentration of sulfide and discovered two linear dynamic ranges with slopes of 0.6896 μA/μM and 5423.5 μA/M in the concentration ranges of 5×10-6 to 1×10-4 M and 3×10-4 to 0.1 M, respectively. The detection limit was achieved 1.32×10−6 mol L−1 (3σ). Also, the electron transfer coefficient (α) and diffusion coefficient (D) of sulfide at the surface of modified electrode were calculated. The proposed electrode was successfully used for the determination of sulfide in tap water and mineral water.