A Novel Application of Bentonite Modified with Copper Ions in the Tetracycline Adsorption: an experimental design study

[Display omitted] •The adsorption of tetracycline on bentonite treated with copper ions was studied.•Cu-bentonites increase the adsorption of TC by complexation and hydrogen bonds.•The best sample of Cu-Bent was able to remove 98.23% of TC in solution.•Cu-Bent may represent a low-cost, sustainable strategy to remove TC. The adsorption of tetracycline (TC) on bentonite treated with copper ions was studied and compared to natural bentonite's adsorption capacity, analyzing the influence of different factors: copper salt, pH and concentration. Results showed that Cu-bentonites increase the adsorption of TC, predominately by complexation and hydrogen bonds. The interaction (-1) between pH and salt type favored the TC adsorption, while the concentration does not have statistical influence. The best sample of Cu-Bent was able to remove 98.23% of TC in solution. This sample was treated with copper nitrate in an acidic medium. In conclusion, the results indicate that Cu-Bent may represent a low-cost and sustainable strategy to remove TC, a contaminant with emerging concern.