Removal of arsenic by a granular Fe-Ce oxide adsorbent: Fabrication conditions and performance

Iron-cerium hydroxide (Fe-Ce), which has shown a high arsenic (V) (As(V)) adsorption capacity in previous studies, was granulated using the vibration dropping method used to prepare small-sized fuel particles. Fabrication studies showed that the sintering process could not be used in the preparation of the granular Fe-Ce (GFC) adsorbent and that the optimum grain size was 1.0 mm for As(V) removal. The optimum sized GFC (GFC-1.0 mm) exhibited a Freundlich adsorption of 18.2 and 11.8 mg g(-1) at an equilibrium concentration of 1.0 and 0.1 mg L-1, respectively. The GFC-1.0 mm also showed equivalent As removal performance to READ, a commercial adsorbent with CeO2 as the sole metal oxide component (about 81%), under both space velocities of 240 and 24 h(-1) in column tests. The cost for the manufacturing of GFC, however, is much lower since iron is the major metal component (about 80%). Energy dispersive X-ray microanalysis (EDX) results showed that As was distributed from the surface to the center of the GFC after the As(V) adsorption experiment, suggesting that nearly all active sites inside the GFC were available for the removal of As(V). The As(V) on the used GFC could be desorbed with an efficiency of 89% using 1.0 mol L-1 sodium hydroxide, and the GFC after desorption showed similar As adsorption performance with the fresh GFC. In conclusion, the GFC consisting of 80% Fe and 20% Ce exhibited As removal performance equivalent to the commercial adsorbent consisting only of Ce. (C) 2010 Elsevier B.V. All rights reserved.