Tetracycline (TC) adsorption from aqueous solutions.

摘要

The adsorption behavior of tetracycline (the most common antibiotic in veterinary) onto carbon black and different size of tires crumb rubber in aqueous medium was evaluated. Tetracycline samples at pH 3.80 with exposition times up to 168 hours at room temperature were placed in contact with crumb rubber, carbon black in the presence and absence of Zn and EDTA. The samples were removed at different time intervals and analyzed by UV-Vis spectrophotometer, liquid chromatography coupled to mass spectrometer (LC-MS) and diode array detection. The results showed that the crumb rubber adsorbed tetracycline (TC) however the sorption capacity was dependent on mesh size, presence of Zn in solution, acid wash and the addition of EDTA as a metal complexing agent. TC removal was variable. At 168 h, the TC removal by the tires crumb rubber of mesh 14-20 and mesh 30 were 48.22 and 59.80 %, respectively. These results were compared with carbon black present in crumb rubber matrix at 10.97--45.60 %, w/w. TC was completely removed from aqueous solution placed in contact with carbon black after 24 hours suggesting its involvement in the TC adsorption by crumb rubber. The analysis also suggested that metals (mainly Zn) present in tires crumb rubber influence the TC adsorption process.; We consider that this work will contribute to expand the tires recycling options using the tires crumb rubber or carbon black to remove TC from aqueous medium.