Humic Acid as a Model for Natural Organic Matter(NOM) in the Removal of Odorants from Water by Cyclodextrin Polyurethanes

BB Mamba1,RW Krause1,TJ Malefetse1,SP Sithole1 and TI Nkambule1 write,Li Jing2 translate(1 Department of Chemical Technology,University of Johannesburg,Johannesburg,2001 2 Graduate School of Chinese Academy of Agricultural Sciences,Beijing,100080)

cyclodextrin polymers; geosmin; 2-methylisoborneol(2-MIB); humic acids

Current practices in some water-treatment facilities have reported that natural organic matter(NOM) blocks the adsorption sites of activated carbon resulting in lower geosmin and 2-methylisoborneol(2-MIB) removal. Humic acid has been reported to compete with geosmin and 2-MIB removal in the same way. The removal of odour chemicals such as geosmin and 2-MIB is important for potable-water treatment by water supply companies and municipalities. We have previously demonstrated that cyclodextrin polyurethanes are capable of removing a number of organic pollutants from water,but are not able to reduce the levels of NOM signifi cantly. We wished to determine if the polymers would selectively remove geosmin and 2-MIB,despite the presence of NOM. Humic acid was chosen as a model for NOM since NOM constitutes about 70% of humic acid. Results obtained from this study indicate that the presence of humic acids at different concentrations could not affect the removal of geosmin and 2-MIB when cyclodextrin polymers were used since 90% removal was achieved. However the UV-Vis analysis showed a low removal of humic acids (3% to 20%).