Abstract
A new point-of-use (POU) technology using porous ceramic filters with a ferric-iron coating was used to achieve simultaneous arsenic (III) and (V) removal along with filtrative disinfection. The surface modified ceramic filters (SMCF) were produced using standard ceramic filter methods with combustible materials to create a porous ceramic during firing, followed by coating with a ferric oxide surface coating. A majority of the testing was conducted using 2.0-cm thick, 1.3-cm diameter ceramic plugs to simulate full-scale filters in column studies. The SMCF was capable of filtering arsenic for long periods of time with essentially no As breakthrough. As in source water was reduced from 250 mu g/L to less than the 10 mu g/L WHO guideline for arsenic for 875 and 1,618 bed volumes (or 360 and 666 effective filter runs) with 0.51 and 2 M iron-coated filters, respectively. There was no significant difference in As(V) or As(III) removal performance over a pH range of 6 to 9. Filtration of lake water containing natural organic matter at 5 mg/L as C reduced performance of As(III) and As(V) removal approximately 34 to 38%, respectively. Other metals including cadmium, copper and chromate were also readily adsorbed by the SMCF while selenate was not.