Removal of tetracycline using modified wheat straw from solution in batch and column modes

Abstract

A novel adsorbent (Zr-WS) was developed from the chemical modification of wheat straw with diethylenetriamine, chloroacetic acid and zirconium (Zr) and its efficacy for adsorption property was assessed using tetracycline (TC) as model pollutant. The materials were characterized by infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and the results indicated that zirconium was successfully loaded on the surface of wheat straw. The adsorption property of TC was performed in batch mode and fixed-bed column mode. The TC uptake was influenced by several factors such as pH, salts, temperature and contact time in batch mode. The adsorption quantity of Zr-WS toward TC was to 77.2 mg·g−1 from equilibrium study at 303 K. Freundlich model was suitable to fit the equilibrium data while Elovich model was better to predict the kinetic process. The adsorption of TC onto Zr-WS was a physical and chemical reaction with endothermic and entropy increasing. The fixed-bed adsorption results showed that high column, high TC concentration and low flow rate were beneficial to the adsorption quantity. Yan model could describe the column adsorption behavior well. There were coordination complexation and ion exchange in the adsorption process. There was some property of regeneration using 0.1 mol·L−1 hydrogen chloride solution as eluting agent. Therefore, Zr-WS could be promising as a new material to remove tetracycline from water.