Adsorption of Pb(II) Ions Using Humic Acid Coated Chitosan-Tripolyphosphate (HA-CTPP) Beads

Abstract

A new humic acid (HA) based adsorbent was prepared by coating humic acid on chitosan tripolyphosphate (CTPP) beads. Humic acid-chitosan tripolyphosphate (HA-CTPP) beads thus obtained were characterized using Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. Swelling capacity studies of CTPP and HA-CTPP beads conducted in the pH range, pH ¼ 1-10 showed that HA-CTPP beads are more stable against swelling than CTPP beads. Equilibration of HA-CTPP beads in water for different pH showed that leaching of HA from the beads is negligible and the beads are stable for adsorption applications. Adsorption of Pb(II) ions onto HA-CTPP beads were studied as a function of various operational parameters such as initial pH, metal ion concentration, and contact time. The results showed that HA-CTPP beads are suitable for Pb(II) ions adsorption and the kinetics of sorption very well fit into pseudo-second order model. The Langmuir model was found to be more suitable for explaining the observed adsorption data, giving a theoretical maximum adsorption capacity of 223.7 mg/g. HA-CTPP beads could possibly find application in the treatment of waste water contaminated with other toxic and/or heavy metals.

Comparison of alternative remediation technologies for recycled gravel contaminated with heavy metals

“…So, some organic matters and chelating/complexing agents can be used as mobilization amendments (Bolan et al, 2014). Humic acid (HA) is a highly effective adsorbent for heavy metal ions under acidic or neutral conditions (El-Eswed and Khalili, 2006), which has absorptivity over Cu(II) (Lin et al, 2011), Cd(II) (Chen et al, 2012), Zn(II) (Li et al, 2010), Cr(III) (Wu et al, 2011), Pb(II) (Sureshkumar et al, 2013), Co(II) (Pehlivan and Arslan, 2006), Hg(II) (Liu et al, 2008), etc. The complex chemical structure of HAs contains a wide variety of functional groups, which can react with metals (Livens, 1991).…”