Competitive adsorption of acetaminophen and caffeine onto activated Tingui biochar: characterization, modeling, and mechanisms

Débora Federici dos Santos, Wardleison Martins Moreira, Thiago Peixoto de Araújo, Maria Manuel Serrano Bernardo, Isabel Maria de Figueiredo Ligeiro da Fonseca, Indianara Conceição Ostroski, Maria Angélica Simões Dornellas de Barros

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2 Citations (Scopus)

Abstract

Tingui biochar (TB) activated with potassium hydroxide (TB-KOH) was synthesized in the present study. The adsorption capacity of TB-KOH was evaluated for the removal of acetaminophen and caffeine in monocomponent and bicomponent solutions. As a result, the study of the TB-KOH characterization as well as the adsorption kinetics, isotherm, thermodynamics, and a suggestion of the global adsorption mechanism are presented. TB-KOH was characterized through physical–chemical analysis to understand its surface morphology and how it contributes to the adsorption of these drugs. Furthermore, modelling using advanced statistical physical models was performed to describe how acetaminophen and caffeine molecules are adsorbed in the active sites of TB-KOH. Through the characterizations, it was observed that the activation with KOH contributed to the development of porosity and functional groups (-OH, C-O, and C = O) on the surface of TB. The monocomponent adsorption equilibrium was reached in 90 min with a maximum adsorption capacity of 424.7 and 350.8 mg g−1 for acetaminophen and caffeine, respectively. For the bicomponent solution adsorption, the maximum adsorption capacity was 199.4 and 297.5 mg g−1 for acetaminophen and caffeine, respectively. The isotherm data was best fitted to the Sips model, and the thermodynamic study indicated that acetaminophen removal was endothermic, while caffeine removal was exothermic. The mechanism of adsorption of acetaminophen and caffeine by TB-KOH was described by the involvement of hydrogen bonds and π-π interactions between the surface of TB-KOH and the molecules of the contaminants. Graphical Abstract: (Figure presented.)
Original languageEnglish
Pages (from-to)53611-53628
Number of pages18
JournalEnvironmental Science and Pollution Research
Volume31
Issue number41
Early online date27 Nov 2023
DOIs
Publication statusPublished - Sept 2024

Keywords

  • Adsorption mechanisms
  • Batch adsorption
  • Pharmaceuticals
  • Theoretical models

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