| Title |
The Removal of Humic Acid and Heavy Metals by Using TiO2 Photocatalysis |
| Authors |
남은정(Eun Jung Nam),조일형(Il Hyoung Cho),최종욱(Jong Wook Choi),이민환(Min Hwan Lee),이홍근(Hong Keun Lee) |
| Abstract |
This study was performed to evaluate the application of TiO₂ photocatalysis for treating humic acid and heavy metals dissolved in water. The optimum condition of operating parameters such as UV illumination, pH. TiO₂ dosage, humic acid concentration and addition of H₂O₂ was suggested for removal of humic acid and heavy metals simultaneously. The results of study were as follows: The removal rate of humic acid and heavy metals by TiO₂ photocatalysis was higher than by UV illumination and by TiO₂ adsorption, therefore it was complied that TiO₂ photocatalysis was more practical method for treating humic acid and heavy metals in water. The removal rate of heavy metals increased more in mixed solution of humic acid and heavy metals than in solution of heavy metals only. The supply of nitrogen gas for reducing high oxygen concentration which restricts the reduction reaction of heavy metals did not influence to heavy metals except Hg(II), but that of nitrogen gas decreased the oxidation rate of humic acid. The increase of UV intensity removed more humic acid and heavy metals because of active photocatalytic reaction, but the removal rate began to decrease with more than 9㎽/㎠ of UV intensity. The decrease of pH increased the removal rate of humic acid due to oxidation reaction, while the increase of pH increased the removal rate of heavy metals except Cr(VI) due to reduction reaction. The removal rate of humic acid and heavy metals generally increased with increase of TiO₂ dosage, but that of heavy metals reduced with more than 0.5g/l of TiO₂ dosage. The increase of humic acid concentration with fixed heavy metal concentration removed more heavy metals effectively, while the removal of heavy metals decreased with more than 30㎎/l of humic acid concentration. The addition of H₂O₂ as an oxidant increased the removal rate of humic acid and heavy metals because of active photocatalytic reaction, while the removal rate of humic acid and heavy metals did not increase with more than 300㎎/l of H₂O₂. |