Influence of the synthesis method of Al-hydroxy intercalated clays on their fulvic acid sorption capacity

The purpose of this study was to investigate the potential use of both Al-hydroxy intercalated clays and 'pillared clays' (calcinated Al-hydroxy intercalated clays) for the removal of fulvic acids (FA) from water. Different preparation procedures of the Al-hydroxy intercalated clays were tested and the products were characterised (XRD and N-2 sorption) and tested for their FA sorption capacity. It was observed that the drying method (oven or freeze-drying) and the calcination step were the most important parameters influencing the FA sorption capacity of the Al-hydroxy intercalated clays. The noncalcined freeze-dried Alhydroxy intercalated clays showed the largest sorption capacity for FA. Comparison with freeze-dried Wyoming bentonite and granular activated carbon showed that this freeze-dried Al-hydroxy intercalated clays are potential good sorbents for the removal of fulvic acids from water. (C) 2005 Elsevier B.V. All rights reserved.