12-phosphotungstic acid supported on BEA zeolite composite with carbonized polyaniline for electroanalytical sensing of phenols in environmental samples

Abstract

Heteropoly acid (HPA) was supported on BEA zeolite by optimized synthesis method yielding samples containing different amounts (20 to 50 wt%) of 12-phosphotungstic acid (HPW). The prepared supported HPW samples were subjected to different post-synthesis procedures including calcination and ultrasonication resulting in BEA-HPW (BPW) hybrid materials. These BPW samples were characterized using SEM, N2-sorption and electrical conductivity measurements. They were subsequently used for the preparation of composites with carbonized polyaniline synthesized in the presence of 5–sulfosalicylic acid, and studied as electrode materials for phenols sensing in acidic, neutral and alkaline media. Linear dependence of current on p–nitrophenol concentration in acidic media was obtained enabling evaluation of limit of detection. Composite electrode gave response to p–nitrophenol presence in alkaline media as well, while no response was recorded in neutral media. The work demonstrates benefits of using novel composite based on BPW hybrid materials and carbonized polyaniline for sensing of phenols in aqueous environmental samples.