Capacity of natural and modified zeolite with cationic surfactant in removal of antibiotic tetracycline from aqueous solutions

Abstract

Introduction: Tetracyclines are organic compounds, which can enter to the aquatic environment and their sustainability is a key issue for the environment. Therefore, this study aimed to study the use of natural and modified zeolite with cationic surfactants for absorption of tetracycline from aqueous solutions.. Materials and Methods: In this experimental study, the adsorbent was made in vitro and its characteristics were analyzed by using XRF, SEM, XRD, FTIR. Also the influence of pH, amount of adsorbent, tetracycline concentration, time and the influence of confounding factors on adsorption, dummy samples of wastewater were investigated. Our laboratory data were compared with Isotherm models and kinetic equations. Regenerative thermal and chemical adsorbent and tetracycline adsorption of real samples of water were taken. All sampling and testing water and sewage were based on standardized tests. Results: The highest adsorption of soluble synthetic tetracycline was happened with both adsorbants in 180 min, 12g/L adsorbent, pH=3 and with the tetracycline concentration of 50mg/L. In these conditions, the efficiency of adsorption of synthetic solution by natural and modified zeolite were 78/8% and 77/4%, respectively and in the actual sample were 60% and 65%, respectively. Adding confounders such as hardness, alkalinity, nitrate, chloride and sulfate to the tetracycline solution, decreased the adsorption efficiency. Using HNO3 and HCl to revive both adsorbents was followed by better result in compare to thermal revival process. Adsorption of tetracycline with both adsorbents followed the pseudo-second-order equation and the Langmuir isotherm. In concentrations greater than 50mg/L of tetracycline, the adsorption by modified zeolite was more efficient. Conclusion: Natural and modified zeolite showed high efficiency in adsorption of Tetracycline solutions and according to the availability, ease of use and ability to produce chemical and thermal reclamation, it is recommended for removal of Tetracycline from the wastewater of pharmaceutical industry.