Comparative studies of Pb~(II) remediation by zero-valent iron and bimetallic Ni/Fe nanoparticles

摘要

In this study synthesized bimetallic Ni/Fe nanoparticles (Ni/Fe NPs) and zero-valent iron NPs (nZVI) were investigated for remediation of Pb~(II) against the effect of various process parameters on removal efficiency. Results of the present study suggested both Ni/Fe bimetallic NPs and nZVI have shown maximum removal of Pb~(II) at pH 5 which enhanced with increasing pH. The v/m ratio study showed that the same volume of lead solution required more bimetallic Ni/Fe NPs than nZVI with identical equilibrium time whereas less corrosion of Ni/Fe NPs showed higher removal efficiency than nZVI at more acidic pH. The values of separation factor were between zero and one indicating favourable sorption for Pb~(II) on both the tested sorbents. Sorption equilibrium isotherms were plotted for metal uptake capacity (q) against different variables studied. Results on adsorption isotherms suggested that adsorption process on Ni/Fe NPs followed Freundlich model i.e. heterogeneous in nature whereas that on nZVI obeyed both Langmuir model i.e. homogeneous and Freundlich model. Catalytic action of nickel counterpart of Ni/Fe NPs and subsequent reversible oxidation and reduction of Ni~0 on its surfaces make more efficient sorbents than nZVI.