Study On Modification Of Black Wattle Bark And Its Adsorption Properties

To make new adsorbents for processing heavy metals wastewater, black wattle bark with high content of tannin was reacted with formaldehyde to fix the tannin in the bark. The adsorption properties of the midified adsorbents to heavy metal ions were investigated. The main contents in this paper include, in chaper 2, a colloidal titration was used to determine tannin content in valonea extract and black wattle tannin extract, and the accuracy and influential factors were discussed. The colloidal titration is showed to have the advangtage of rapidity, simplicity and small sample dosage comprared with traditional hide powder method. In chaper 3, tannins in black wattle bark were immobilized in situ by cross-linking reaction of formaldehyde. The effects of the reaction conditions on yields of in situ immobilized black wattle bark were disccused. It was found that this new adsorbent has good adsorption capacity to Fe³⁺ ion. In chapter 4 the adsorption behavior of the in situ immobilized black wattle bark to Cr⁶⁺ was studied, and its adsorption mechanism was presumed. The results were that the adsobent has good adsorption capacity to Cr⁶⁺. In chapter 5, the oxidation of the in situ immobilized black wattle bark was carried out to improve adsorption quantity of the bark to Cu²⁺ ion, and the factors influencing adsorption of the oxidized bark to Cu²⁺ was investigated...