Keywords: 
• Pistia stratiotes L /
• antimony ion(Ⅲ) /
• biosorption

Abstract: The dried Pistia stratiotes L. biomass used as a biosorbent for the removal of Sb3+ from aqueous solutions was investigated under the experimental conditions， such as various time， initial pH， sorbent dosage， shaker’s rotating speed and temperature. The biosorption mechanism was explored by FTIR analysis， kinetic and isothermal biosorption experiments. Results showed that the Sb3+ in the water could be removed up to 76.8% at pH of 6.8， biosorbent dosage of 1 g/25 mL， shaker’s rotating speed of 100 r/min， adsorption time of 120 min， and initial concentration of Sb3+ of 50 mg/L， and ambient temperature (25±1)℃. The kinetics of biosorption was relatively fast， about 52.7% of Sb3+ removal occurred within 10 min and equilibrium was attained within 60 min. Initial pH of solution was the important factor affecting biosorption and optimal pH was 6.8. The adsorption capacity increased with the increase of biosorbent dosage， rotating speed and reaction temperature in an appropriate range. By the analysis of FTIR， the adsorption included chemical and physical processes. The pseudo-second-order kinetics model could better characterize the biosorption processes of the metals than the pseudo-first-order kinetics model. The biosorption process could be well described using isothermal adsorption equations of Langmuir and Freundlich model. The Langmuir adsorption isotherm model best reflected the adsorption characteristics. The maximum adsorption capacity of the biosorbent was 1.394 mg/g at 298 K. The results of this study show that waste Pistia stratiotes L. biomass is a good absorbent for removal of Sb3+ from wastewater， which is a strategy of controlling waste by waste.