Gum to remove toxic metal from water
doi:10.1038/nindia.2014.83 Published online 23 June 2014
Researchers have developed an ecofriendly way to remove the toxic heavy metal lead from contaminated water1. Their method uses guar gum, which is produced from the ground seeds of guar beans. It could potentially be used to treat wastewater and purify contaminated drinking water.
Existing techniques for removing harmful lead from water are inefficient and tedious. The researchers have developed a simple and effective technique for removing lead from contaminated water. They prepared aqueous solutions of guar gum and then tested their efficacy in binding and removing lead ions from wastewater.
The researchers found that guar gum adsorbed 56.7% of lead from wastewater at a pH of 4.5. At a pH of 6, the adsorption efficiency of guar gum decreased by 5.4% due to a reduction in the size of the guar gum adsorbent. The guar gum exhibited a higher adsorption efficiency at increased gum concentrations: the gum adsorbed 33.4% of lead from wastewater with a gum concentration of 500 parts per million, whereas its adsorption efficiency increased to 56.7% at a gum concentration of 1,000 parts per million.
The study revealed that the adsorption efficiency of guar gum gradually increased with increasing contact time because a longer contact time allowed more lead ions to bind to guar gum molecules. Increasing the temperature also enhanced the adsorption efficiency of the guar gum solution by generating more active sites on the guar gum, enabling it adsorb more lead ions.
1. Pal, A. et al. Polyelectrolytic aqueous guar gum for adsorptive separation of soluble Pb(II) from contaminated water. Carbohydr. Polymer. 110, 224–230 (2014)