Enhanced sorption of triclosan from aqueous solution to Rhizopus oryzae biomass biofunctionalized with lipids.

In this research, a lipid-functionalized sorbent from Rhizopus oryzae biomass was produced applying a biofunctionalization technique where the biomass chemistry was modified by metabolic changes induced during the fungal growth by operating variables of bioreactor. Biosorbent was characterized by the point of zero charge, scanning electron microscopy, Fourier transformation infrared spectroscopy and lipid content. The ability of biosorbent to remove triclosan (TCS) from aqueous solution was investigated in batch experiments. The effect of lipid content (Y _X/L ) in biosorbent on the TCS sorption was also studied and the reaction conditions (pH, biomass dose and agitation rate) to maximize the TCS sorption was optimized by a central composite design 2 ³ . At optimal reaction conditions, the TCS biosorption was characterized by kinetic, equilibrium and thermodynamic studies. Results showed that biosorbent is a slightly acidic to neutral material with affinity to TCS; the higher Y _L/X the higher sorption capacity of TCS. The interactions between the high-Y _L/X biosorbent and TCS was favored at pH 5.68, 115.9 rpm and 60.50 mg of biosorbent. The pseudo-first order model was useful to model the kinetic data, although the intraparticle diffusion was identified as the major rate-limiting step. The Freundlich isotherm described properly the TCS biosorption. However, the Freundlich isotherm was modified to include the Y _L/X effect. The TCS biosorption was spontaneous and endothermic, but it was governed by weak interactions, mainly Van der Waals forces and hydrogen bonds, and to a lesser extent π-π interactions between aromatic rings of TCS.