[Removal of tetracycline by a kind of nano-sized amorphous carbon].

The experiments were conducted to investigate the adsorption behavior of tetracycline on a kind of nano-sized amorphous carbon,which was synthetized in a molten salt electrochemical system,comprising a eutectic mixture of Li-Na-K carbonates. The results showed that,the carbon powder had a good adsorption performance. At 298 K,the maximum adsorption capacity of tetracycline was 127. 76 mg·g-1. The adsorption data could be well fitted by the pseudo-second-order model and the Freundlich isotherm. Also,the thermodynamic tests for the adsorption were conducted. The adsorption was endothermic and spontaneous reaction with chemical bond as the dominant. The adsorption was p H dependent. The adsorption capacity reached the maximum when solution p H was 4 in the range from 2 to 11. The existence of cations had little effects on the adsorption. The adsorption capacity increased with the concentration of cations to a certain extent. Ion exchange may be one of the adsorption mechanisms,as well as,electric attraction and hydrogen bond. Moreover,desorption experiments were carried out in 0. 25 mol·L-1Ca Cl2 or Na Cl solution respectively. Desorption efficiency ranged from 7. 42% to 25%,which was at a relatively low level. The result indicated that the chemical adsorption process was strong.