Efficient Removal of Tetracycline and Bisphenol A from Water with a New Hybrid Clay/TiO2 Composite

Morenike O Adesina; Inga Block; Christina Günter; Emmanuel I Unuabonah; Andreas Taubert

doi:10.1021/acsomega.3c00184

Efficient Removal of Tetracycline and Bisphenol A from Water with a New Hybrid Clay/TiO₂ Composite

ACS Omega. 2023 Jun 5;8(24):21594-21604. doi: 10.1021/acsomega.3c00184. eCollection 2023 Jun 20.

Authors

Morenike O Adesina^{1

2

3

4}, Inga Block¹, Christina Günter⁵, Emmanuel I Unuabonah^{2

3}, Andreas Taubert¹

Affiliations

¹ Institute of Chemistry, University of Potsdam, D-14476 Potsdam, Germany.
² African Centre of Excellence for Water and Environment Research (ACEWATER), Redeemer's University, PMB 230 Ede, Osun State 232101, Nigeria.
³ Department of Chemical Sciences, Redeemer's University, PMB 230 Ede, Osun State 232101, Nigeria.
⁴ Lead City University, Ibadan 200255, Oyo State, Nigeria.
⁵ Institute of Geosciences, University of Potsdam, D-14476 Potsdam, Germany.

Abstract

New TiO₂ hybrid composites were prepared from kaolin clay, predried and carbonized biomass, and titanium tetraisopropoxide and explored for tetracycline (TET) and bisphenol A (BPA) removal from water. Overall, the removal rate is 84% for TET and 51% for BPA. The maximum adsorption capacities (q_m) are 30 and 23 mg/g for TET and BPA, respectively. These capacities are far greater than those obtained for unmodified TiO₂. Increasing the ionic strength of the solution does not change the adsorption capacity of the adsorbent. pH changes only slightly change BPA adsorption, while a pH > 7 significantly reduces the adsorption of TET on the material. The Brouers-Sotolongo fractal model best describes the kinetic data for both TET and BPA adsorption, predicting that the adsorption process occurs via a complex mechanism involving various forces of attraction. Temkin and Freundlich isotherms, which best fit the equilibrium adsorption data for TET and BPA, respectively, suggest that adsorption sites are heterogeneous in nature. Overall, the composite materials are much more effective for TET removal from aqueous solution than for BPA. This phenomenon is assigned to a difference in the TET/adsorbent interactions vs the BPA/adsorbent interactions: the decisive factor appears to be favorable electrostatic interactions for TET yielding a more effective TET removal.