Artemia Shell-support Zirconium Oxide Nanoparticles For Enhanced Heavy Metal Removal In Water

In this thesis, selective adsorption performances of the Artemia shell toward Cu2+、Pb2+ were examined, subsequently, a bio-composite adsorbent(Zr-Lc) by impregnating zirconium oxide onto porous Artemia shell were fabricated and the uptake of heavy metals and sorption mechanism was also elucidated, which provides a promising technical support for enhanced heavy metals removal in water and preparation of environmental bio-composite adsorbent.In the first section of the work, the unique heavy metal adsorption onto Artemia shell was studied. It was observed that the adsorption performance was a p H-dependent process with the optimal p H values of neutral solutions. The present competing ions were also exert adverse adsorption behaviors with the influence sequence as Ca2+ > Mg2+ > Na+. Additionally, the optimum adsorption capacity on Cu2+ is 24.29mg/g at 55℃, as for Pb2+, 246.72mg/g is arrival when 20℃. So, the adsorption isotherm can be well described by the classic Freundlich model. Sorption kinetics of Artemia shell on Cu2+ equilibrated in 40 min can be well fitted with the pseudo-second-order kinetics model, while that for Pb2+ equilibrated in 10 min, the pseudo-first-order kinetics model might be more suitable. Moreover, The adsorption-desorption experiment was examined with 4 runs, indicating that the adsorbent can be readily regenerated by strong acid solutions. The column test of Artemia shell on Pb2+ suggests that the level of Pb2+ in effluent was below 10μg/L.In the second section of the work, a composite adsorbent(Zr-Lc) was prepared by loading zirconium oxide onto porous Artemia shell. The results of SEM and TEM indicated that the zirconium oxide was dispersed successfully. The optimal p H values for adsorption onto composited Zr-Lc were neutral p H. Comparing with the primitive Artemia shell and a traditional ion-exchange resin D-001, Zr-Lc exhibits more favorable adsorption toward Cu2+、Pb2+ even in the presence of Ca2+ at high levels. The adsorption process of Zr-Lc on Cu2+ based on an endothermic reaction and the adsorption isotherm can be well described by the Langmuir model. While the adsorption process of Zr-Lc on Pb2+ based on an exothermal reaction and the adsorption isotherm can well described by the Freundlich model. The optimum adsorption capacities on Cu2+ and Pb2+ are 44.55 mg/g and 399.08 mg/g at 55℃ and 20℃. Compared to Artemia shell, the adsorption equilibrium time of Zr-Lc on Cu2+、Pb2+, 100 min and 50 min, is longer. The adsorption kinetics of Zr-Lc on Cu2+、Pb2+ can be fitted with the pseudo-second-order kinetics model. The results of column test indicate that Zr-Lc displays good sorption performance for heavy metal removal, which is a promising adsorbent in water treatment field.