Wastewater treatment from heavy metals using extracts of wood processing waste (oak bark)

The paper considers the issues of using extracts from wood processing industry waste (oak bark) for wastewater treatment from heavy metal ions (Cr+6) are considered. The principle of purification is the formation of aggregates, formed by the contact of organic colloidal compounds (tannins) with positively charged heavy metal ions. It is established that the maximum formation of a precipitate is observed in acid media (pH = 2.5). This is due to the fact that during the oxidation of the substance the compounds of hexavalent chromium pass to the salts of trivalent chromium, which forms a precipitate. To improve the efficiency of treatment, oak bark was crushed on a shredder and a hammer mill with the subsequent production of an alkaline extract.