Modeling $\mathrm{As}\left(\mathrm{V}\right)$ Removal in Iron Oxide Impregnated Activated Carbon Columns

Iron oxide impregnated onto an activated carbon $\left(\mathrm{FeAC}\right)$ has a high arsenic (As) removal capacity with the potential to be used in existing activated carbon column systems. Objectives of this research were to investigate $\mathrm{As}\left(\mathrm{V}\right)$ removal from aqueous-phase systems using fixed-beds packed with $\mathrm{FeAC}$ and to determine if the triple layer model (TLM) with the homogeneous surface diffusion model (HSDM) could describe $\mathrm{As}\left(\mathrm{V}\right)$ removal in the columns. Rapid small-scale column tests (RSSCT) were conducted at various empty bed contact times (EBCT). Effluent $\mathrm{As}\left(\mathrm{V}\right)$ breakthrough $(10\mathrm{\mu }\mathrm{g}∕\mathrm{L})$ was incipient for the 0.20-min EBCT experiment, whereas $\sim 2300$ bed volumes of water at 1-mg/L inlet concentration of $\mathrm{As}\left(\mathrm{V}\right)$ was treated at an EBCT of $2.1\min$ before breakthrough occurred. The TLM with three $\mathrm{As}\left(\mathrm{V}\right)\text{-}\mathrm{FeAC}$ surface reactions coupled with the HSDM provided accurate prediction of $\mathrm{As}\left(\mathrm{V}\right)$ removal in the RSSCT.