Magnetic nanocomposite of filamentous algae activated carbon for efficient elimination of cephalexin from aqueous media

Discharge of antibiotics into the environment can cause problems like increase of the microorganisms' resistance, disturbing the ecological balance and increasing the allergy in humans. In this research, an activated carbon was produced from filamentous algae and then magnetized with Fe3O4. The adsorbent size was nano-scale and its characteristics were studied using XRD, FT-IR, FE-SEM, BET and VSM techniques. The response surface method (RSM) was employed to optimize the operating parameters and determine the best conditions for cephalexin removal by novel composite of AC-Fe3O4. The various parameters in the process, such as reaction time, initial pH, adsorbent dose, initial concentration of cephalexin and effect of cations and anions that could interfere in the adsorption of cephalexin were evaluated in three levels. The proposed quadratic model was found to be best suggested model for the adsorption process (R-2=0.99094 and R-adj(2)=0.9991). According to results, the parameters such as cephalexin concentration, the adsorbent dose, the reaction time and the pH value were found to be 28.16 mg/L, 2 g/L, 30.04 and 3.02, respectively. Experimental results showed that the adsorption of cephalexin followed Langmuir isotherm (R-2=0.9803). Also, the results showed cephalexin adsorption on the composite fitted pseudo-second-order kinetics. The study showed that the AC-Fe3O4 adsorbent has high efficacy for eliminating cephalexin from aqueous solution.