title: Nitrate absorption through hydrotalcite reformation.
abstract: Thermally activated hydrotalcite based upon a Zn/Al hydrotalcite with carbonate in the interlayer has been used to remove nitrate anions from an aqueous solution resulting in the reformation of a hydrotalcite with a mixture of nitrate and carbonate in the interlayer. X-ray diffraction of the reformed hydrotalcites with a d(003) spacing of 7.60 A shows that the nitrate anion is removed within a 30 min period. Raman spectroscopy shows that two types of nitrate anions exist in the reformed hydrotalcite (a) nitrate bonded to the 'brucite-like' hydrotalcite surface and (b) aquated nitrate anion in the interlayer. Kinetically the nitrate is replaced by the carbonate anion over a 21 h period. Two types of carbonate anions are observed. This research shows that the reformation of a thermally activated hydrotalcite can be used to remove anions such as nitrate from aqueous systems.
authors.affiliation: Inorganic Materials Research Program, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia. r.frost@qut.edu.au
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Musumeci