Polyaniline Nanofibers as a Sustainable Adsorbent for Cr(VI) and Hg(II) Ions Detoxification

ABSTRACT Heavy metal pollution in water presents a significant environmental and health hazards, seeking for effective and sustainable remediation methods. This research examines the adsorption efficacy of polyaniline nanofibers (PANI‐NF) for the uptake of chromium (Cr(VI)) and mercury (Hg(II)) ions from dilute solutions. The synthesized PANI‐NF was characterized by using X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE‐SEM), high‐resolution transmission electron microscopy (HR‐TEM), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) isotherm, and zeta potential analysis to elucidate its structural and physicochemical properties. The adsorption efficiency was methodically assessed under different experimental parameters; including reaction time, initial heavy metal ion concentration, adsorbent dosage, and pH of metal ion solution. Different mathematical models further examined the adsorption mechanism to evaluate adsorption isotherms and kinetic behavior. The synthesized PANI‐NF, devoid of any structural alterations like doping or nanocomposite integration, exhibited maximum adsorption capacity and outstanding removal efficiency of 142.85 mg g −1 , 97% for Cr(VI) and 166.66 mg g −1 , 91% for Hg(II), respectively, under optimum adsorption conditions (contact time (45 min), initial metal ion concentration (20 mg L −1 ), adsorbent dosage (20 mg), and pH (7)), indicating its excellent efficacy in removing heavy metal ions as compared to previously reported studies. Electrostatic interactions and surface binding processes primarily govern the adsorption process. The findings of the present work demonstrate that PANI‐NF is a viable and economical adsorbent material for wastewater treatment applications. This research advances sustainable adsorption technologies and establishes a basis for future investigations to enhance the adsorption efficiency of PANI‐based materials for environmental remediation.