Electrochemical Sensors Based on Polyaniline Nanocomposites for Detecting Cd(II) in Wastewater

A novel imprinted polyaniline-gold nanoparticle (PANI-AuNPs) nanocomposite modified glassy carbon electrode was strategically constructed and systematically explored for sensitive voltammetric quantification of toxic heavy metal Cd(II) in wastewater. Morphological studies revealed uniform dispersion of AuNPs (avg. diameter ~13 nm) across PANI polymer matrix. Electrochemical testing displayed 320% enhanced oxidation current and 5.7 times higher electron transfer rate constant for Cd(II) relative to bare electrode owing to synergistic effects between highly conductive PANI chains and ultrafine nanosized AuNPs. Exceptionally low 1.2 μg/L limit of detection and wide 5-100 μg/L dynamic linear range was accomplished. The sensor demonstrated commendable accuracy (96-103% recovery) in detecting Cd(II) from spiked industrial effluent and tap water samples. The outstanding sensitivity surpasses previous reports on Cd(II) imprinted sensors. Fundamental mechanistic insights gained on interfacial structure-dynamic relationships can stimulate rational engineering of high-efficiency imprinted nanohybrid materials towards target toxins. This novel PANI-Au electrochemical detector provides a versatile, inexpensive, field-deployable analytical tool for stringent water quality monitoring ensuring food and environmental safety.