Biosorption of Zn (Ⅱ) by dried Azolla imbricata biomass
满江红干体对锌离子的生物吸附

The dried A. imbricata biomass as a biosorbent for the removal of Zn2+ from aqueous solution under various experimental conditions was investigated. This study showed that the kineties of biosorption was relatively fast, about 62.9% of the biosorption occurred within 5 min and equilibrium was attained within 30 min. The initial pH of solution strongly affected the metal biosorption, with pH 6 being identified as the optimal condition. The adsorption capacity increased with the increasing of the initial Zn2+ concentration of the solution, while decreased with the increasing of the adsorbent dosage. The adsorption isotherm followed the Langmuir isotherm where the maximum adsorption capacities onto A. imbricata was 57.5 mg/g for Zn2+. The data from five biosorption-desorption cycles indicated that the biosorption capacity of the biomass was not much affected by repeated operations and regeneration process. The reusability of A. imbricata biomass in the treatment of Zn2+-laden wastewater is viable.