Adsorption of metal and uranyl ions onto amidoximated Pinus densiflora bark

Pine (Pinus densiflora) bark was chemically modified by grafting with acrylonitrile (AN) through Fenton reaction and conversion of the cyano group to an amidoxime group by reaction with hydroxylamine. Treatments of pine bark with 160 mM H(2)O(2) at 40A degrees C yielded similar to 70% grafting in 6-h reaction. After alkali hydrolysis of amidoximated pine bark (AOPB), its adsorption capacity (q (e)) for copper ions was largely increased from 0.5 to 1.8 mmol/g. Adsorption of the hydrolyzed AOPB (HAOPB) followed the pseudo-second-order kinetic model. Among the metal ions tested, the order of adsorption capacity (q (e)) predicted by the kinetic model at equilibrium time was Hg(2+) > UO(2) (2+) > Cd(2+) > Cu(2+) > Zn(2+) > Ni(2+). The adsorption process was pH-dependent, and the adsorption equilibrium was observed in the pH range of 6-7 for all the metal ions. Even though pine bark is a good adsorbent for Hg(2+) and UO(2) (2+) ions, it had a poor affinity for the other ions tested. It was obviously found that HAOPB had very high adsorption abilities for heavy metal and uranyl ions.