Application of cork as adsorbent for water and wastewater treatment using ciprofoxacin as pharmaceutical model

Abstract

The present study investigated the biosorption efciency of cork against the antibiotic ciprofoxacin, contained within a synthetic mixture made of atrazine, bisphenol A and methylene blue. The biosorbent was characterized for its functional groups via Fourier Transform Infrared spectroscopy, for its point of zero charge by a pH meter, and for its morphology via brightfeld microscopy. The efect of temperature (25, 35, and 45 °C), pH (3.0, 7.0, and 9.0), adsorbent mass (0.25, 0.5, and 0.75 g), initial ciprofoxacin concentration (5, 25, and 50 mg L−1), and the presence of ions (MgCl2, KCl, Na2SO4, and CaCl2) was evaluated for ciprofoxacin adsorption onto cork. Even though it followed the pseudo-second-order and Elovich kinetic models, the isotherm data ftted the Freundlich model better, suggesting a heterogeneous adsorptive process. An adsorption capacity of 2.88 mg g−1 was reached at a temperature of 25 °C and a pH 7.0, using 0.25 g raw cork with a ciprofoxacin initial concentration of 25 mg L−1. Raw cork regeneration was studied after fve cycles of adsorption/desorption, with a 2±0.1% loss of adsorptive efciency from the frst to the ffth cycle. The potential of the adsorbent for the wastewater treatment was then evaluated, presenting a reduction of contaminants by 94.65±4.8% after 24 h of treatment. This manuscript showed that cork presents a double environmental interest, as it may improve waste management and is a promising adsorbent material for water and wastewater treatment, contributing to public health and environmental protection.