Biosorption of tetracycline antibiotics by Lactarius deliciosus biomass

Abstract

In this study, Lactarius deliciosus biomass was used as a biosorbent for the biosorption of three tetracycline antibiotics, chlortetracycline (CTC), doxycycline (DC), and tetracycline (TC), from aqueous solution. The biomass was characterized by Fourier Transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The effect of biosorbent amount (0.01-0.1g), pH (3.0-8.0), initial antibiotic concentration (30-300 mg/L for CTC and DC, and 5-50 mg/L for TC), contact time (2-120 min), and temperature (7 degrees C, 16 degrees C, 25 degrees C) were investigated. The maximum biosorption amount of CTC, DC, and TC was 216.4 +/- 4.2 mg/g (pH 4.0), 121.2 +/- 6.2 mg/g (pH 3.0), and 23.2 +/- 2.1 mg/g (pH 7.0) at 25 degrees C, respectively. The biosorption amount of tetracyclines decreased with increasing temperature demonstrating that the biosorption processes were exothermic. The biosorptions of tetracyclines were favorable with negative Delta G degrees values for all temperatures. CTC and DC biosorption processes were well fitted to the pseudo-second-order kinetic and Freundlich isotherm models. TC biosorption data obeyed the pseudo-first-order kinetic model. Tap and drinking water samples spiked with tetracyclines were used as real samples for biosorption. The results showed that L. deliciosus biomass could be effectively used as a biosorbent for tetracycline antibiotics with high adsorption capacities.