The jeopardy of hazardous synthetic dye wastes to the environment and human health has rapidly increased. In this investigation, a nanocomposite of In2O3/Polyaniline (In2O3/PANI) has been fabricated to remove the noxious anionic acid blue 25 (AB25) dye by adsorption. Various characterization techniques including FT-IR, XRD, TGA, SEM, EDX, TEM, BET, and Zeta potential analysis were carefully used to verify that the nanocomposite was successfully synthesized. The developed adsorbent features a porous structure with an average particle size of 58.43 nm. The results revealed that only 0.007 g of the nanocomposite can efficiently remove 95.5 % of AB25 within 90 min. In addition, the AB25 adsorption data were accurately matched to the Langmuir and Toth isotherm models with a maximum adsorption capacity of 253.36 mg/g. The adsorption results also kinetically followed the pseudo-second-order model. Thermodynamically, the adsorption AB25 was spontaneous and endothermic. Notably, the nanocomposite displayed auspicious adsorption selectivity towards the anionic AB25 compared to the cationic dye methylene blue (MB). Interestingly, the as-fabricated In2O3/PANI nanocomposite retained satisfactory adsorption characteristics after five consecutive cycles with a maximal removal percentage exceeding 83 %, suggesting it is a viable and effective option for eliminating dangerous anionic dyes from aquatic environments.

Keywords: Adsorption, Polyaniline, Nanocomposites, Acid blue 25, In2O3