Efficient and selective removal of copper from aqueous solution by nanosized hydrated zirconium oxides loaded in vermiculite

Novel nanosized hydrated zirconium oxide (ZrO(OH)(2)) loaded in vermiculite (VMT) was successfully prepared and used to remove Cu2+ from aqueous solution. The adsorbent was characterized by XRF, XRD, SEM and TEM. The adsorption process of Cu2+ could reach equilibrium within 30 min and its kinetic data could be well described by pseudo-second-order model. The isotherm data could be described better by Langmuir model and the calculated maximum adsorption capacity was 96.23 mg/g. The adsorption of Cu2+ on nanosized ZrO(OH)(2) loaded in vermiculite (NZV) was intensively affected by solution pH and different electrolytes. NaClO4 inhibited the adsorption of Cu2+, while NaCl and NaNO3 promoted the Cu2+ adsorption on NZV. The adsorption enhancement by NaNO3 was much significant than that of NaCl due to more ternary complexes forming among Cu2+, NO3- and the surface of NZV. The adsorption speed and capacity of Cu2+ were apparently reduced in the presence of Ni2+ in solution, while Cu2+ showed a higher affinity to adsorbent than Ni2+. The selective adsorption of Cu2+ in Cu-Ni mixed solution could be easily achieved in the presence of 0.8 mol/L of NaNO3, leading to 100% removal of Cu2+ and around 5% removal of Ni2+.