Improved Cu and Zn sorption on oxidized wheat lignocellulose

We studied the effect an oxidizing treatment of a lignocellulosic substrate, extracted from wheat bran, on the sorption of Cu and Zn. Oxidizing agents, such as potassium permanganate (KMnO4) or sodium periodate (NaIO4), creates oxygenated functions, e.g. alcohol and carboxylic acid, which increase the density of functional sites and the binding capacity of lignocellulose towards copper and zinc. We found that the treatment with KMnO4 is the most efficient, with an increase of about 30-40% metal ion binding, compared to 15-25% using NaIO4. The investigation of the oxidation process shows that the efficiency of KMnO4 can be attributed to its affinity towards insaturated double bonds of lignin entities. Oxidized lignocellulose is thus a promising, efficient, and cheap biomaterial for the decontamination of wastewater.