Fixed-Bed Adsorption of Ciprofloxacin onto Bentonite Clay: Characterization, Mathematical Modeling, and DFT-Based Calculations

Abstract

The objective of this paper was to examine the adsorption of the antibiotic ciprofloxacin (CIP) in a calcined Verdelodo (CVL) clay-packed fixed-bed system. The characterization study of the fresh and contaminated clay indicated filling of the clay pores by the CIP (pore volume decreased from 65.4 to 31.1 cm 3 g −1 ) and did not evidence significant changes in the clay texture. The fixed-bed system reached a breakthrough adsorption capacity of 0.038 mmol g −1 (12.6 mg g −1 ) and a mass transfer zone of 4.29 cm. Five mathematical models were fitted to the breakthrough curves, and the dual-site diffusion displayed the best fit to the experimental data (R 2 > 0.98). The adsorption performance of CIP was compared to that of the antibiotic ofloxacin, reported in the literature, in which density functional theory (DFT) computations were performed to clarify the particularities of the adsorption of both compounds onto CVL clay.

Rational Construction of Two Zn–Organic Frameworks for Selective Luminescent Sensing and Efficient CO2 Chemical Fixation

“…Complex 2 has HOMO and LUMO energies of −5.753 and −3.251 eV, respectively. Meanwhile, according to the literature, the lowest occupied orbits of CIP and LEVO antibiotics are −1.18 and −1.71 eV, respectively. , Compared with the energy-level configurations, the LUMO of CIP and LEVO antibiotics is higher than that of 1 and 2 , which promotes the electron transfer of CIP and LEVO to the lowest occupied orbit of both complexes during photoexcitation along with the luminescence enhancement . Therefore, the photoinduced electron transfer (PET)-sensing mechanism is the main reason causing the luminescent enhancement.…”

Quantitative Evaluation of the Effects of Salt Concentration and pH on the Self-Assembly of Kaolin Nanoplatelets

“…These methods include X-ray diffraction (XRD), 20,21 infrared spectroscopy (IR), 22,23 nuclear magnetic resonance (NMR), 24,25 colloidal approach, 26,27 scanning electron microscopy (SEM), 28,29 transmission electron microscopy (TEM), 30,31 atomic force microscopy (AFM), 22,32 molecular dynamics (MD) simulations, 33−35 and density functional theory (DFT) calculations. 36,37 However, despite their best efforts, the complex and dynamic nature of clay microstructures under different conditions still poses many challenges and uncertainties. The primary usages and limitations of these methods in analyzing the microstructure of clay can be summarized as follows:…”

Unraveling the Origin of Enhanced Activity of the Nb2O5/H2O2 System in the Elimination of Ciprofloxacin: Insights into the Role of Reactive Oxygen Species in Interface Processes

“…2 These arguments show that the removal of excessive amounts of antibiotics from industrial and municipal sewage is a significant challenge. One of the most effective methods of their depletion from wastewater is the sorption process (immobilization of the antibiotic molecules on the surface of various adsorbents, e.g., activated carbons or chars, 4 mineral clays, 5 amorphous silica, 6 or zeolites 7 ). Its efficiency is strongly affected not only by the properties of the target pollutant and parameters of the wastewater (temperature, pH, presence of other pollutants, etc.)…”