Decontamination of Polluted Water by Treatment with a Crude Humic Acid Blend

The use of humic acid for contaminant extraction from environmental matrices is an attractive concept because of the natural origin of the material and its low pollution potential. The problem of availability and the need for alkaline extraction were circumvented by the use of an unrefined leonardite humic acid (LHA) material used as received. This mined product has a high humic acid content, is inexpensive, and is available in bulk. LHA, applied without alkaline extraction, was used in the decontamination of water containing organic and inorganic test pollutants. The former included pyrene, difenzoquat, and rhodamine B base, while the latter were comprised of Pb 2+, Zn 2+, Ni 2+, Cu 2+, Sr 2+, Cd 2+, As 3+, Ag +, and Mg 2+ . Simulated acidic waste solutions were treated by both batch precipitation and column extraction, with the pollutants applied singly and as mixtures. In the precipitation procedure, commercial lime was used as the coagulant, and virtually complete removal of the metals was achieved. Pyrene and difenzoquat were also removed, but rhodamine B base was not. With LHA column elution, all three organic compounds were fully extracted from waste solutions, including those containing mixed contaminants. Removal of metals by column treatment gave encouraging results, with Pb 2+, Cu 2+, and Sr 2+ being extracted most effectively.