The aim of this research work is to investigate the exploitation of the nano zinc oxide composite was used as an adsorbent for the removal of Pb(II), Hg(II), Cd(II) and Bi(III) heavy metal ions from aqueous solution. The resulting adsorbent n-ZPFR was characterized by SEM with EDS, BET, TEM, FT-IR, XRD, DTA and TGA analyses and tested for metal adsorption. The maximum adsorption performance was achieved for Pb(II), Hg(II), Cd(II) and Bi(III) ions from aqueous solution by n-ZPFR was investigated as a function of some parameters such as initial metal ion concentration (0.01M), contact time (60min), dose (0.250g) and temperature (328K). Langmuir, Freundlich, Dubinin Kaganer-Radushkevich, Temkin and Jovanoic isotherm models were used to interpret the experimental data. The data obeyed both D-R and Jovanoic models (R2=0.999) indicating a monolayer adsorption of heavy metal ions onto the homogeneous surface. The linear plot of Temkin isotherm showed adsorbent adsorbate interactions. Moreover, the energy obtained from D-R isotherm (2579.8-426.9 KJ/mol) indicated a physical adsorption of the metal ions onto the adsorbent surface. Kinetic studies indicated that Pb(II),Hg(II),Cd(II) and Bi(III) ions adsorption followed the pseudo-second-order model. Kinetics; controlled by both liquid-film and intra-particle diffusion mechanisms. The thermodynamics parameters (∆G0, ∆H0 and ∆S0) of adsorption systems indicated spontaneous and endothermic process. The results suggested that n-ZPFR composite is economical, eco-friendly and capable to remove Pb(II), Hg(II), Cd(II) and Bi(III) from natural water resources.
