Arsenic adsorption via iron-preloaded activated carbon and zero-valent iron.

This research focused on removing arsenic (As) from groundwater by coupling iron-tailored activated carbon with iron solubilization. This was achieved by solubilizing iron grains that were interspersed within the tailored activated carbon. A commercially available bituminous coal carbon was preloaded with iron by an evaporation method. With natural groundwater as the source, the media processed 25,000 bed volumes (BV) of water before >10 µg/L As breakthrough occurred. In comparison, when 30% zero-valent iron (NI) grains were interspersed with iron-preloaded bituminous coal carbon, As breakthrough > 10 µg/L occurred at 45,000 BV. The As breakthrough corresponded to when most of the NI source had become visibly corroded. Although some solubilized iron escaped through the granular activated carbon media, this iron could be captured in a subsequent sand or activated carbon filter in order to yield water that would meet both primary and secondary drinking water standards. Field-scale tests are required to determine whether results at large scale corroborate the laboratory findings. [ABSTRACT FROM AUTHOR]