Removal of Tetracycline from Water by Palygorskite
Palygorskite(PFL) is clay consisting of modulated 2:1 layers. The tetrahedral sheets of PFL are continuous, but every two tetrahedral ribbons along the b axis exhibit a reversal of the orientation of their apical O atoms. This reversal leads to the periodic interruption of the octahedral sheet, which, unlike that of smectite, becomes discontinuous (Chisholm 1992; Chiari et al. 2003; Giustetto et al. 2004). The sorption of tetracycline(TC) on PFL was studied as a function of pH, ionic strength, temperature, pH adsorption edge PFL contents and tetracycline concentrations under ambient conditions using a batch technique. The TC sorption capacity on PFL is as high as 90 mg/g at pH 8.7, and decreased to 35 mg/g at pH 11. Because PFL is a fiber structure, XRD analysis are not found any variation, thus the adsorption is on the surface of PFL.
The results from this study indicate that the palygorskite could be a good candidate as a sorbent to remove TC from water on one hand, and could be a great environmental sink for TC on the other hand. This dual property deems further study on interactions between a broad spectrum of antibiotics and different types of clays, for example, rectorite.