Magnetically retrievable PANI-Fe3O4 nanocomposite for efficient dye removal from tannery wastewater: Mechanistic insights and performance assessment
Year: 2026
Type: article
Abstract: Leather dyeing techniques create highly pigmented and toxic effluents that pose ecological problems due to synthetic azo dyes and organic loading. This study will create, investigate, and use a magnetically separable polyaniline-Fe 3 O 4 nanocomposite to remove mixed anionic pigments from tannery wastewater. The proposed material improves surface activity and simplifies post-treatment separation over polymer-supported composites by combining conductive polymer functionality with magnetic recovery. In situ oxidative polymerization generated the nanocomposite, which FT-IR, XRD, and SEM examinations confirmed successful synthesis, structural integrity, and many surface-active sites. Batch adsorption studies showed that pH, adsorbent dosage, contact duration, and settling time optimally removed dye at 89.45% at pH 5.6 and 0.30 g. In adsorption studies, the process followed the Langmuir isotherm (R 2 = 0.9954) and pseudo-second-order kinetics (R 2 = 0.9980). The Van’t Hoff plot (R 2 = 0.9916) shows endothermic adsorption (ΔH° = +33.931 kJ mol -1 ) with increased disorder (ΔS° = +28.582 J K -1 mol -1 ) and negative ΔG° at higher temperatures, indicating entropy-driven physisorption enhanced by diffusion and binding. FT-IR band shifts and surface morphology changes also confirm monolayer physisorption on a uniform surface, with electrostatic interactions, π-π stacking, and hydrogen bonding as the primary removal mechanisms. After optimal treatment, COD dropped 48.13%, BOD 18.99%, and salinity 28.65%. Thus, the produced nanocomposite improves effluent quality significantly. The adsorbent also exhibited above 70% regeneration effectiveness across multiple adsorption-desorption cycles. Therefore, this study uniquely combines structural characterization and adsorption mechanism investigation for a magnetically recoverable PANI-Fe 3 O 4 nanocomposite adsorbent in real tannery effluents. • PANI-Fe 3 O 4 nanocomposite developed via in situ oxidative polymerization • 89.45% dye removal from real tannery wastewater under optimized conditions • Reduction of COD, BOD, and salinity improved effluent quality • Endothermic physisorption confirmed by thermodynamic study • Electrostatic and π-π interactions with hydrogen bonding are found in the mechanism
Institution: Khulna University of Engineering and Technology
Language: English
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,190
OpenAlex ID: W7118760632