Effective Removal of Heavy Metal Ions Using Glycerol and Starch Xanthate

Abstract

Glycerol and insoluble starch xanthates were synthesised and effectively used in theremoval of Pb, Cd, and Cu from aqueous solutions. The insoluble metal complex formed betweenthe sulphur atoms in the xanthates and the heavy metals were easily separated. Lower dosageof glycerol xanthate was required in each case, with the optimum molar ratio of metal ions toglycerol xanthate (M2+/GX) of 2. Moreover, the use of glycerol xanthate requiring no pHadjustments gave a 100 % heavy metal removal within the range of the detection limit. As forthe insoluble starch xanthate, there was a remarkable metal scavenging activity when thexanthate contained high amount of sulphur per molecule (10.12% S) and when the pH wasadjusted to 6. Butyl xanthate was also synthesised to make a good comparison with the glyceroland insoluble starch xanthate. The xanthates from these two sustainable materials (Starch andglycerol) are proven to be more effective in metal scavenging activity. Fourier transform infraredand CHNS elemental analyses were used to prove the evidence of xanthation, in addition,carbon-13 nuclear magnetic resonance spectroscopy was used to characterise the glycerolxanthate.