Issue 11, 2023

A porous bentonite–coconut husk composite for the enhanced adsorption of selected emerging contaminants from aqueous solution

Abstract

The preparation of bentonite clay–coconut husk composite (BECH) via microwave-assisted carbonization, the activation of BECH with HCl (BECH-H) and KOH (BECH-K) and the adsorption of ciprofloxacin, tetracycline, and bisphenol A from aqueous solutions by the resultant carbon materials are highlighted in this study. The adsorbents (BECH, BECH-H and BECH-K) were characterised by transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and N2 adsorption–desorption analysis using the BET model. The results from these analyses showed sufficient interactions between bentonite and coconut husk. The adsorbents exhibited high specific surface areas (284–456 m2 g−1) showing potential to be used in adsorption studies. The Sips model provided the best fit to the adsorption data when data from the equilibrium experiment were fitted to the Freundlich and Sips models. BECH-H and BECH-K demonstrated the highest affinity for bisphenol A with BECH-H having the highest adsorption capacity (472.9 mg g−1). BECH also had the greatest preference for the adsorbents, having adsorption capacities of 199.7 mg g−1 for ciprofloxacin, 183.5 mg g−1 for bisphenol A and 281.7 mg g−1 for tetracycline. Results showed high removal efficiencies for the ECs studied (>90%) at a low dosage of the adsorbents (50 mg). The kinetic data of all the adsorbents are best described by the pseudo-second-order kinetic model. Adsorption reactions were heterogeneous in nature with chemisorption being the rate-limiting step. These findings suggest that these adsorbents could be excellent materials for effectively treating EC-contaminated water.

Graphical abstract: A porous bentonite–coconut husk composite for the enhanced adsorption of selected emerging contaminants from aqueous solution

Article information

Article type
Paper
Submitted
11 Febr. 2023
Accepted
05 Aug. 2023
First published
08 Aug. 2023
This article is Open Access
Creative Commons BY-NC license

Environ. Sci.: Adv., 2023,2, 1554-1565

A porous bentonite–coconut husk composite for the enhanced adsorption of selected emerging contaminants from aqueous solution

A. O. Egbedina, S. B. Odejobi, B. J. Akinbile, A. A. Ambushe, B. I. Olu-Owolabi and K. O. Adebowale, Environ. Sci.: Adv., 2023, 2, 1554 DOI: 10.1039/D3VA00033H

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