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 N2 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 Al-hydroxy 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.