Abstract
Chloroquine has been reported as an effective drug for the treatment of COVID-19 and with the rise in its administration and continued use, metabolites of chloroquine invariably find their way into the environment. There are many concerns recently on the presence of pharmaceuticals in the aquatic environment, hence the need for environmental remediation via effective adsorbent. Plantain peel activated carbon-supported zinc oxide (PPAC-ZnO) nanocomposite was prepared and characterized using physicochemical and spectroscopic techniques. The rate of uptake of chloroquine by PPAC-ZnO nanocomposite was investigated by batch technique under different operational parameters. PPAC-ZnO nanocomposite was characterized by various physicochemical techniques by SBET = 606.07 m2g-1, pH(pzc) = 4.98 surface area by Saer's method = 273.4 m2g-1. The carboxylic, phenols, lactone, and basic sites were determined by the Boehm method. Chloroquine uptake was confirmed by FTIR and SEM before and after adsorption. Change in morphology after adsorption was revealed by scanning electron microscopy (SEM). X-ray diffraction (XRD) showed the crystallinity of PPAC-ZnO nanocomposite. The batch adsorption experiment results showed that adsorption capacity increased with an increase in temperature. The maximum chloroquine sorption was 78.89% at a concentration of 10 ppm and a temperature of 313 K. Equilibrium sorption fitted well to Langmuir and Temkin isotherms with a high correlation coefficient (R 2) of 0.99. Pseudo-second-order best described the kinetic data and adsorption mechanism was pore diffusion dependent. Thermodynamics parameters (ΔG = - 25.65 to - 28.79 kJmol-1; ΔH = 22.06 kJmol-1 and ΔS = 157.69 Jmol-1) demonstrated feasibility, spontaneity, and endothermic behavior of the process with degrees of randomness. The activation energy for adsorption was less than 40 kJmol-1 suggesting a physisorption mechanism. This study results revealed that PPAC-ZnO nanocomposites are a sustainable and effective adsorbent for the removal of pharmaceutical waste.