Hydrated ferric oxide (HFO)-encapsulated tea waste for enhanced lead(II), cadmium(II), and copper(II) removal from waters

AbstractHydrated ferric oxide (HFO) was impregnated successfully within tea waste by precipitation, and a novel hybrid adsorbent named HFO–TW was prepared. The sorption characteristics of HFO–TW toward Pb(II), Cd(II), and Cu(II) in aqueous solution were investigated. HFO–TW was characterized by X-ray diffraction and Fourier transform infrared analysis. Three heavy metals sorption onto HFO–TW is pH-dependent, and the higher pH value is more helpful for sorption at evaluated pH range. HFO–TW can exhibit strong sorption selectivity toward three metal ions, and the removal efficiencies fall only 21% for Pb(II), 34% for Cd(II), and 10% for Cu(II) in the presence of competing ions Ca(II), Mg(II), and Na(I) at concentration 50 times higher than target metal ions. The maximum sorption capacities calculated by Langmuir equation for Pb(II), Cd(II), and Cu(II) removal onto HFO–TW are 87.84, 26.01, and 22.97 mg/g, respectively. The sorption process of three heavy metals could approach equilibrium within 60 min. Both ...