Green synthesis of carbon nanotubes functionalized with iron nanoparticles and coffee husk biomass for efficient removal of losartan and diclofenac: Adsorption kinetics and ANN modeling studies

Heloisa P S Costa; Emanuele D V Duarte; Flávio V da Silva; Meuris G C da Silva; Melissa G A Vieira

doi:10.1016/j.envres.2024.118733

Green synthesis of carbon nanotubes functionalized with iron nanoparticles and coffee husk biomass for efficient removal of losartan and diclofenac: Adsorption kinetics and ANN modeling studies

Environ Res. 2024 Mar 21;251(Pt 2):118733. doi: 10.1016/j.envres.2024.118733. Online ahead of print.

Authors

Heloisa P S Costa¹, Emanuele D V Duarte¹, Flávio V da Silva¹, Meuris G C da Silva¹, Melissa G A Vieira²

Affiliations

¹ School of Chemical Engineering, University of Campinas, Av. Albert Einstein, 500, Campinas, São Paulo, Brazil.
² School of Chemical Engineering, University of Campinas, Av. Albert Einstein, 500, Campinas, São Paulo, Brazil. Electronic address: melissag@unicamp.br.

PMID: 38521353
DOI: 10.1016/j.envres.2024.118733

Abstract

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 CaCl₂ 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.

Keywords: Carbon nanotubes; Green functionalization; Pharmaceuticals contaminants; Wastewater treatment; machine learning.