Surface Modification of Tea-Waste-Based Biochar Adsorbent: Synthesis, Characterization, and Batch Adsorption for the Removal of Zidovudine ARV Drug and Phenol

Tumelo Nortica Mashoene; Anny Leudjo Taka; Samson O. Akpotu; Isiaka A. Lawal; Michael John Klink

doi:10.3390/app13137493

Applied Sciences (Jun 2023)

Surface Modification of Tea-Waste-Based Biochar Adsorbent: Synthesis, Characterization, and Batch Adsorption for the Removal of Zidovudine ARV Drug and Phenol

Tumelo Nortica Mashoene,
Anny Leudjo Taka,
Samson O. Akpotu,
Isiaka A. Lawal,
Michael John Klink

Affiliations

Tumelo Nortica Mashoene: Department of Biotechnology/Chemistry, Vaal University of Technology, Vanderbijlpark Campus, Vanderbijlpark 1911, South Africa
Anny Leudjo Taka: Department of Biotechnology/Chemistry, Vaal University of Technology, Vanderbijlpark Campus, Vanderbijlpark 1911, South Africa
Samson O. Akpotu: Department of Biotechnology/Chemistry, Vaal University of Technology, Vanderbijlpark Campus, Vanderbijlpark 1911, South Africa
Isiaka A. Lawal: Department of Biotechnology/Chemistry, Vaal University of Technology, Vanderbijlpark Campus, Vanderbijlpark 1911, South Africa
Michael John Klink: Department of Biotechnology/Chemistry, Vaal University of Technology, Vanderbijlpark Campus, Vanderbijlpark 1911, South Africa

DOI: https://doi.org/10.3390/app13137493
Journal volume & issue: Vol. 13, no. 13
p. 7493

Abstract

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Domestic, agricultural, and industrial waste has been investigated as a substitute for activated carbon adsorbents. For instance, the transformation of tea waste to biochar can be utilized as a substitute for activated carbon adsorbents. In this study, tea waste-based biochar adsorbents (biochar, biochar/reduced graphene oxide (biochar/rGO), biochar/reduced graphene oxide/deep eutectic solvent-cetyltrimethylammonium bromide (biochar/rGO/DES-CTAB), and biochar/reduced graphene oxide/deep eutectic solvent-glycerol (biochar/rGO/DES-glycerol)) were synthesized by simple thermal treatment of tea waste and sucrose followed by modification with reduced graphene oxide and deep eutectic solvents. The obtained materials were characterized using a range of spectroscopy techniques, Fourier Transformed Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy–Energy-Dispersive X-ray Spectroscopy (SEM–EDS), Brunauer, Emmett, and Teller (BET) surface area analysis, and pH at point of zero charge (pH PZC). The obtained results showed that the principal material, i.e., biochar was modified, and FTIR results confirmed the presence of added functional groups. SEM images revealed surface structural changes, and BET showed a decrease in pore size from 10.16 nm to 6.87 nm. The synthesized materials were applied for the removal of ZDV and phenol from the aqueous medium. Batch adsorption studies were conducted to optimize operating parameters such as the adsorbent dose, solution pH, contact time, and initial concentration. Pseudo-first-order (PFO), Pseudo-second-order (PSO), and intraparticle diffusion (IPD) kinetic models were determined to investigate the mechanism of the adsorption process. The coefficient of correlation, R2, was used to determine the best fit of the kinetic models. The adsorption results showed that the DES-glycerol-modified adsorbent was more efficient in removing the pollutants ZDV and phenol than biochar, biochar/rGO, and biochar/rGO/DES-CTAB adsorbents. In addition, the results showed that an acidic medium of pH 2.00 and a contact time of 1 h 30 min and 30 min is sufficient for removing ZDV and phenol, respectively, from an aqueous medium.

Published in Applied Sciences

ISSN: 2076-3417 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Engineering (General). Civil engineering (General); Science: Biology (General); Science: Physics; Science: Chemistry
Website: http://www.mdpi.com/journal/applsci

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