Single and Competitive Removal of Pb(II) in the Presence of Ni(II) using Polyacrylamide Grafted Rice Husk

Abstract

In a quest to find efficient adsorbents for metal ions, studies on various adsorbents for metals have been of interest since the past several decades. The present study is focused on the removal of Pb (II) ions from aqueous solution using poly acrylamide grafted rice husk by batch studies. Industrial waste waters generally contain metals present as mixtures, therefore the effect of Ni (II) on the removal of Pb(II) from mixtures of Pb(II)+Ni(II) ions has also been investigated. The adsorbent has been prepared by the treatment of rice husk with acrylamide in the presence of N,N-methylene bis acrylamide and potassium persulphate. The adsorbent has been characterised by infrared spectral studies. Maximum adsorption obtained is 93% at pH 5, metal ion concentration 300mg/L in 180mins at 298K. Isotherm analyses show that both Langmuir and Freundlich isotherm models are best obeyed. The process is endothermic and spontaneous in nature and follows pseudo first order kinetics. Intraparticle diffusion also occurs but is not the rate determining step. Application of Langmuir competitive model for the binary system shows that  adsorption of Pb(II) has been supressed by presence of Ni(II) ions. Studies suggest that the adsorbent is effective and can find industrial applicability.