Ciprofloxacin adsorption onto CNT loaded Pumice: Adsorption Modelling, kinetics, equilibriums and reusability studies

A novel CNT-derived Pumice adsorbent (P-CNT3) was successfully synthesized as an efficient adsorbent for Ciprofloxacin (CIP) removal from aqueous solutions. In present study, P-CNT3 composite synthesized by hydrothermal technique was loaded with multiwalled carbon nanotube (CNT) using sonification to remove CIP antibiotic. P-CNT3 composite were characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses. Adsorption performance was studied by adjusting the pH, contact time, initial CIP concentration, temperature and adsorbent dosage in a batch reactor to obtain the maximum adsorption capacity (qm). The maximum adsorption capacity (qm) was achieved in 240 min at pH <= 5). The adsorption process of P-CNT3 followed the pseudo-first-order kinetic model (R2 = 0.989) and sips isotherm model (R2 = 0.991), and qm to adsorb CIP was 28.6 mg/g. The illustrated adsorption mechanism shows that hydrophobic interactions, electrostatic and non-electrostatic interactions, suggests CIP adsorption. Over the temperature range of 298-318 K, the thermodynamic parameters Delta G degrees, Delta S degrees and Delta H degrees were calculated. The adsorption reactions were shown to be spontaneous and endothermic. Furthermore, activation energy suggested a physisorption mechanism for P-CNT3. In addition, regeneration study shows that the P-CNT3 can be reused five times with excellent results in CIP adsorption. Based on these findings, P-CNT3 can be considered a feasible lowcost adsorbent for CIP removal. Hence, the prepared P-CNT3 composite can be used as an inexpensive and a promising adsorbent for the removal of other pharmaceutical compounds.