Effect of solution pH on adsorption of cefradine by wheat straw and thermodynamic analysis

As to many pollutants in aqueous solution, wheat straw is considered to be an environment friendly and low-cost adsorbent. Cefradine is a kind of broad-spectrum semisynthetic antibiotics widely used in clinical practices, which causes pollution in natural water bodies. As such, natural wheat straw was tentatively used for adsorptive removal of cefradine. Effect of solution pH on the adsorption of cefradine by wheat straw was investigated. It was found that the optimal solution pH for cefradine adsorption was pH 5.0. The typical functional groups present on raw and exhausted wheat straw after cefradine adsorption were confirmed through fourier-transform infrared spectroscopy. The isotherm data were analysed by Langmuir, Freundlich and Temkin isotherm models. It demonstrated that Freundlich model described the adsorption isotherm better. By Langmuir model, the maximal adsorption capacity for cefradine was 39.5 mg/g at 298 K. The thermodynamic analysis indicates that the cefradine adsorption process on the wheat straw was endothermic in nature and the increase of reaction temperature was beneficial to the uptake of cefradine. This demonstrates that wheat straw could be an ideal and cost-effective bio-sorbent used for effective removal of antibiotics such as cefradine from water. © 2019 Technoscience Publications. All Rights Reserved.