Lipid-Biofunctionalized Rhizopus oryzae Biomass for Enhanced Triclosan Sorption from Water

Abstract In this study, a lipid-functionalized sorbent derived from Rhizopus oryzae biomass was produced using a biofunctionalization strategy, in which biomass composition was modified via metabolically induced changes during the fungal growth under nitrogen-limited and oxygen limited cultivation conditions. The biosorbent was characterized in terms of point of zero charge, surface morphology (SEM), functional groups (FTIR), and lipid content. Batch biosorption experiments were conducted to evaluate the removal of triclosan (TCS) from aqueous solutions. The effect of lipid content, expressed as the lipid-to-biomass yield (Y X/L ), on TCS sorption was systematically investigated. Furthermore, the reaction conditions (pH, biomass dose and agitation rate) were optimized using a 2 3 central composite design to maximize sorption performance. The biosorbent was a slightly acidic to neutral material and showed enhanced sorption capacity with increasing Y X/L . Under optimal conditions (pH 5.68, 115.9 rpm and a biomass dose of 60.50 mg), a sorption efficiency of up to 88.2 ± 0.62% was achieved. Kinetic analysis indicated that the pseudo-first order model adequately described the sorption process, although the intraparticle diffusion was identified as the main rate-limiting step. Equilibrium data were best fitted by the Freundlich isotherm, which was further modified to incorporate the effect of Y L/X . The thermodynamic analysis revealed that TCS sorption was spontaneous and endothermic, suggesting a process predominantly governed by physical interactions. Overall, these findings demonstrate that lipid-biofunctionalized R. oryzae biomass is a sustainable biosorbent with promising potential for TCS removal under controlled laboratory conditions.