Removal of Tetracycline Antibiotic from Aqueous Solution Using Zeolite-X Modified by Pyridium Bromide Cationic Surfactant:A Laboratory Study

Antibiotics are among the pollutants that have entered uncontrollably in the environment, and lead to serious environmental problems such as disrupting aquatic ecosystems, and causing health problems for humans and other organisms.  Therefore, it is necessary to remove them from the environment. In the current study, zeolite modified by cationic surfactant of cetylpyridinium bromide hydrate was employed as an adsorbent to remove tetracycline from the aqueous solution.

In this laboratory study, the effect of main variables, including initial tetracycline concentration, solution pH, adsorbent dosage, and reaction time on the adsorption process was investigated. Adsorbent structural features were analyzed using FESEM, pH of zero point of charge (pHZPC), and Fourier transform infrared spectroscopy (FTIR). Finally, isotherm and kinetics of the adsorption process were studied.

The removal efficiency of 99.9% was achieved under the optimum condition, including initial tetracycline concentration of 11.5 mg L-1, pH of 6.0, the adsorbent dosage of 4.0 g L-1, and reaction time of 50 min. The maximum adsorption capacity (qm) was found to be 65.41 mg g-1. The adsorption process for tetracycline removal followed the Langmuir isotherm (R2=0.9996) and second-order kinetic model (R2=0.9957).

The adsorption process using zeolite modified by cationic surfactant was a suitable technique with high efficiency for removing tetracycline from contaminated wastewater.