Optimisation of 3D-Organized Mesoporous Silica Containing Iron and Aluminium Oxides for the Removal of Arsenic from Groundwater

Abstract

The development of mesoporous adsorbents coated with iron and aluminium oxides has been optimised for the removal of arsenic. 3D-organised mesoporous silica KIT-6 was used as a host for iron and aluminium oxides loading in single or mixed conditions. Material properties were characterized using BET and TEM analysis. The high surface area and porosity of the sorbents and their 3D organization has been ascertained. Materials produced were used in adsorption studies for removing both As(III) and As(V). KIT-6 coated with 8 % iron oxides showed an As(III) and As(V) removal capacity of 10.47 and 6.26 mg.g-1 while the same silica matrix coated with 8 % aluminium oxides displayed an As(III) and As(V) removal capacity of 7.73 and 38.78 mg.g-1 respectively. The use of mixed Fe-Al oxides coated sorbents showed the possibility to tailor the adsorption towards one of the two arsenic species. These materials are expected tobe superior adsorbents when used in column systems as they will be saturated simultaneously with both As(III) and As(V) thus avoiding the use of an oxidation step.