Bioremediation of Crystal Violet Dye Using <scp> <i>Sapindus mukorossi</i> </scp> Functionalized Iron‐Oxide Nanoparticles From Coprecipitation Method

ABSTRACT The textile industry is a water‐intensive industry that disrupts aquatic ecosystems by releasing recalcitrant chemicals like crystal violet (CV) dye characterized by its carcinogenic and mutagenic nature. Ethanolic extract of saponin‐rich Sapindus mukorossi was employed in the synthesis of biogenic iron oxide nanoparticles (IONP). The study evaluates the effectiveness of these nanoparticles in the removal of CV dye by examining variables including initial dye strength (10–250 ppm), nanoparticle dosage (1–10 g/L), and contact time (3–60 min) at various temperatures (303–323 K). Maximum CV dye removal was found to be 83% at 303 K. Using isotherms and thermodynamic studies, the current study has shown that the CV removal process with IONP is endothermic (Δ H = 15 403 J/mol, Δ S = 127 J/mol·K). The negative values of Δ G ° (−54.004 to −56.552 kJ/mol from 303 to 323 K) indicate that the CV dye removal process was favorable and spontaneous. Using XRD, FTIR, SEM, and BET analysis, the structural and functional characteristics of iron oxide nanoparticles for CV dye removal were further investigated, highlighting their potential as effective and environmentally acceptable substitutes for conventional wastewater treatment techniques.