Study on the influence factors of the photocatalysis degradation of Humic Acid

YAN Xiao-ju^1,2, YU Shui-li¹, SHI Wen-xin¹, ANG Xu³, LI Li-zheng¹

1.School of the Municipal and Environment,Harbin Institute of Technology,Harbin 150090,China;2.College of Hydrology and Water Resources,Hohai University,Nanjing 210098,China;3.School of Geography,Harbin Normal University,Harbin 150025,China



Abstract:

The effects of Humic Acid (HA) concentration,pH value and aeration on the photocatalysis degradation of HA by the silica gel supported TiO2 were studied.Moreover,the effect of aeration on the generation of hydroxyl radicals are investigated.The experimental results indicated that the hydroxyl radicals are generated during the photocatalysis process.The generation of hydroxyl radicals is increasing linearly with the reaction time,approximately.Moreover,the generation rate of hydroxyl under the condition of aeration is 1.57 times of that under the condition without aeration,which is the main influent factor on the reaction rate.Therefore,the reaction rate constant with and without aeration is 0.012 min-1 and 0.0063 min-1,respectively.The degradation rate decreases when the initial HA concentration increases,which is due to that more TiO2 active sites are occupied by HA when the HA concentration is higher.Moreover,HA can absorb large amount of photons,which can prevent those available photons to arrive at the activate TiO2 particles.The degradation rate decreases when increasing pH value,which is due to that the adsorption of HA on the TiO2 particles is weakened and not benefit for the degradation process of HA.

Key words:  photocatalysis  Humic Acid  hydroxyl radicals  aeration  TA

DOI：10.11916/j.issn.1005-9113.2011.03.017

Clc Number:TU991.2

Fund: