Abstract:This research attempted to tailor granular activated carbon (GAC) with organic acid (citric acid and EDTA) and iron. Rapid small-scale column tests (RSSCTs) were set up to appraise the adsorption breakthrough behavior of those modified carbons. Amount of iron thus loaded increased with the increase of organic acid and iron concentration. At concentrations of 0.1 mol/L EDTA and iron respectively, the tailored carbon obtained an iron content of 6.18% as compared to that of 0.24% for virgin GAC. There was remarkable improvement in adsorption capacity for arsenic after carbon tailoring. EDTA-Fe tailored GACs showed bed volumes to breakthrough 10 times that of virgin GAC both for As(V) and As(III). In general, As(V) adsorption decreased with the increase of pH. In contrast, adsorption of As(III) was found to be less dependent on pH at pH 6 to 9. Also, the irons loaded onto GAC by this organic acid-Fe method were mostly amorphous and were stable.