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This research investigated the adsorption of propranolol (PROP) by functionalized green carbon nanotubes (MWCNT-B), assessing the influence of pH, in addition to kinetic, equilibrium, and thermodynamic studies and reuse of the material. For this purpose, speciation of PROP and the point of zero charge (pH PZC ) of MWCNT-B were performed, indicating a pKa of 9.67 and pH PZC of 3.31. The adsorption tests at different pH values revealed that in the range of pH 3 to 9, there is no significant variation in PROP uptake, despite this, at pH 11, the removal decreases. Regarding PROP adsorption, the equilibrium time ranged from 30 to 90 min, and the PFO model best represented the kinetic data. The Langmuir model was more predictive in representing isotherms (R 2  > 0.95), and the adsorption process was spontaneous and favorable (ΔG <  - 20 kJ mol -1 ) and indicated exothermic behavior (ΔH =  - 33 kJ mol -1 ) for PROP removal. In addition, the material showed satisfactory thermal regeneration results and can be reused for four cycles. The results suggest that MWCNT-B is an attractive adsorbent and exhibits effective removal of propranolol from aqueous matrices., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The presence of emerging contaminants in wastewater poses a global environmental challenge, requiring the development of innovative materials or methods for their treatment. This study focused on the production of green functionalized carbon nanotubes (CNTs) and using them in the adsorption of the pharmaceuticals Losartan (LOS) and Diclofenac (DIC). The efficiency of the methodology was verified by characterization techniques. Elemental composition analysis indicated a significant increase in the iron content after the green functionalization, proving the effectiveness of the method. Thermogravimetric analysis showed similar thermal degradation profiles for pristine CNTs and functionalized CNTs, indicating better post-functionalization thermal stability. BET analysis revealed mesoporous characteristics of CNTs, with increased surface area and pore volumes after functionalization. X-Ray diffraction confirmed the preservation of the lattice structure of the CNTs post-functionalization and post-adsorption, with changes in peak broadening suggesting surface modifications. LOS and DIC adsorption were evaluated via kinetic studies at four different concentrations (0.1-0.4 mmol/L) that were best represented by the pseudo-second order model, suggesting chemisorption mechanisms, with faster and higher uptakes for DIC (0.084-0.261 mmol/g; t eq  = 5 min) when compared to LOS (0.058-0.235 mmol/g; t eq  = 20 min). The curves were also studied via artificial neural networks (ANN) and revealed that the best ANN architecture for representing the experimental data is a network with [3 5 5 2] neurons trained using the Bayesian-Regularization algorithm and the Log-sigmoid (hidden layers) and Linear (output layer) transfer functions. The desorption study showed that CaCl 2 had better performance in CNT regeneration, reaching its removal capacity above 50% up to 3 cycles, for both pharmaceuticals. These findings reveal the potential of the developed material as a promising adsorbent for targeted removal of pollutants, contributing to advances in the remediation of emerging contaminants and the application of artificial intelligence in adsorption research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This study explores the utilization of adsorption and advanced oxidation processes for the degradation of ofloxacin (OFL) and ciprofloxacin (CIP) using a green functionalized carbon nanotube (MWCNT-OH/COOH-E) as adsorbent and catalyst material. The stability and catalytic activity of the solid material were proved by FT-IR and TG/DTG, which also helped to elucidate the reaction mechanisms. In adsorption kinetic studies, both antibiotics showed similar behavior, with an equilibrium at 30 min and 60% removal. The adsorption kinetic data of both antibiotics were well described by the pseudo-first-order (PFO) model. Different advanced oxidation processes (AOPs) were used, and the photolytic degradation was not satisfactory, whereas heterogeneous photocatalysis showed high degradation (⁓ 70%), both processes with 30 min of reaction. Nevertheless, ozonation and catalytic ozonation have resulted in the highest efficiencies, 90%, and 70%, respectively, after 30-min reaction. For AOP data modeling, the first-order model better described CIP and OFL in photocatalytic and ozonation process. Intermediates were detected by MS-MS analysis, such as P313, P330, and P277 for ciprofloxacin and P391 and P332 for ofloxacin. The toxicity test demonstrated that a lower acute toxicity was observed for the photocatalysis method samples, with only 3.1 and 1.5 TU for CIP and OFL, respectively, thus being a promising method for its degradation, due to its lower risk of inducing the proliferation of bacterial resistance in an aquatic environment. Ultimately, the analysis of MWCNT reusability showed good performance for 2 cycles and regeneration of MWCNT with ozone confirmed its effectiveness up to 3 cycles., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This paper investigated the uptake of CIP and OFL in single and multicomponent adsorptive systems using modified carbon nanotubes (CNTs) as adsorbent material. The characterization analyses of the pre- and post-process material by XPS, TG/DTG, FT-IR, SEM/EDS, and XRD helped in the elucidation of the mechanisms, indicating greater involvement of n-n and π -π interactions. In the kinetic studies, the simple systems with CIP and OFL were similar, both showed equilibrium time around 20/30 min and increased adsorptive capacity with increasing initial drug concentration. In the multicomponent system, different fractions of CIP and OFL were tested and the time to reach equilibrium also varied between 20 and 30 min. In general, the adsorption capacity of CIP is slightly lower than that of OFL under the conditions tested. The selectivity analysis of the system showed that the selectivity's of the two drugs are identical in equimolar fractions. The mathematical modeling of the kinetic data indicated that in monocomponent systems, the model of pseudo-second order (PSO) adequately described both CIP and OFL kinetics. Furthermore, with the implementation of Artificial Neural Networks (ANN), it was possible to obtain a more assertive prediction of the behavior of single and binary systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)