Removal of Cd(II) Ions from Wastewater by Compounding an O-Xanthogenated Chitosan Schiff Base and Fe(III) Ions

The removal of Cd(II) ions from wastewater via the compound flocculation of O-xanthogenated chitosan Schiff base (XCTS) and Fe(III) ions was studied. The compound flocculant Fe(III)/XCTS was effective in an acid range of pH 3.0–5.0. When the pH was 3.0 and the compound ratio of [Fe(III)]/[XCTS] was 1:12, the compounded system Fe(III)/XCTS had the best effect on the removal of Cd(II) ions; the removal rate of Cd(II) ions was greater than 99.5%, and the Cd(II) ion concentration of the treated wastewater met the 0.1 mg L−1 limit set by the National Integrated Wastewater Discharge Standard of China. Furthermore, while studying the compound flocculation of Fe(III) ions and XCTS, we found that the approach enhanced the growth and structure of the flocs in the progress of removing Cd(II) ions.