AWWA ACE62948

This slide presentation begins by presenting background information on research showing how extensive herbicide and fertilizer application on agricultural lands has resulted in groundwater contamination. Removal of triazine herbicides by zerovalent iron (ZVI) through chemical reduction has been investigated and reported recently. Removal rate and efficiency of triazine herbicides by ZVI process are pH dependence. Although the pH-dependent trends of triazine removal rate and efficiency are similar for various studies, magnitudes are very different. There are at least four possible explanations, including: the surface of the ZVI were used; the difference in the initial concentrations of ATR were used; the mixing mechanisms were employed; and, ZVI-induced Fenton oxidation. The objective of this particular study were to: lucidate conditions that oxidation or reduction involved; and, investigate the effects of pH and ZVI dosage, etc. The experimental section involved chemicals of reagent grade, and ZVI powder (Acros Organics Co., USA) with nominal particle size of 325 mesh (40 µm). A schematic of the experimental setup is given, along with analysis of: the removal efficiency of atrazine as a function of reaction time at various pH conditions; concentration of Fe²⁺ and Total Fe content for pH 4.0 system; and, effect of purging (pH 3). Includes figures.