TRICHLOROPHENOL ADSORPTION ON LAYERED DOUBLE HYDROXIDE - A POTENTIAL SORBENT

The objective of this work was to assess the adsorption mechanism of t richlorophenol (TCP) on a layered double hydroxide, the hydrotalcite c ompound [Mg3Al(OH)(8)]2CO3.XH(2)O), (HT), and its calcined product Mg3 AlO4(OH), (HT500), as exploring their potential use as phenol sorbents . TCP adsorption on HT and HT500 was measured by batch equilibration t echnique at diverse solid/solution ratios, pH, contact times and TCP c oncentrations. X-ray diffraction and Fourier Transform-infrared (FT-IR ) spectroscopy were applied to the adsorption products to uscertain TC P-HT interactions. The results showed that TCP adsorption on HT is ver y low and seems to occur as anion exchange reaction only on the extern al surface sites at the entrance of the interlayer spaces. TCP adsorpt ion on the calcined compound HT500 is high and irreversible and occurs by the reconstruction of the layered structure. X-ray powder diffract ion and FT-IR spectroscopy showed that TCP adsorbed at the interlayer spaces as phenolate form that besides OH- and CO3= ions compensate the positive layer charge. The possible use of HT500 as phenol sorbents i n waters is suggested.