Humic and Fulvic Acids as Potentially Toxic Metal Reducing Agents in Water

Industrial activity has contributed to potentially toxic metal pollution in various ecosystems throughout the world. In this study, the ability of humic and fulvic acids (isolated from lignite with a simple, rapid, and inexpensive method) to reduce toxic metals' concentration of contaminated water is examined. More specifically, the effect of these compounds is tested on water contaminated (at various concentrations) with Cd, Cr, Cu, Ni, and Pb. The determination is performed by inductively coupled plasma-optical emission spectrometry. The maximum binding capacity is presented by fulvic acids in the following order Cr>Pb>Ni>Cu>Cd (97.8, 96.5, 95.4, 95.1, and 83.3%, respectively), while for humic acids it is Pb>Ni>Cr>Cu>Cd (81.3, 70.7, 68.6, 67.0, and 66.8%, respectively). The binding activity is also tested on water contaminated with two metals simultaneously. In these cases, the existence of two metals in water changes the reduction ability of humic and fulvic acids (positively or negatively).