TY - JOUR
T1 - Functionalizing non-smectic clay via methoxy-modification for enhanced removal and recovery of oxytetracycline from aqueous media
AU - Ashiq, Ahmed
AU - Walpita, Janitha
AU - Vithanage, Meththika
N1 - Funding Information:
Research Council grant [ASP/01/RE/SCI/2017/83] of the University of Sri Jayewardenepura, Sri Lanka, is acknowledged for financial support. Instrument support was provided by the Instrument Centre, and Nanocomposites Research Group at Faculty of Applied Sciences of the University of Sri Jayewardenepura set up by the Accelerating Higher Education Expansion and Development (AHEAD) Operation of the Ministry of Higher Education, Sri Lanka funded by the World Bank.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/8
Y1 - 2021/8
N2 - Kaolinite and methoxy-modified kaolinite were used as novel adsorbents for oxytetracycline (OTC) removal and recovery from aqueous media. Batch adsorption experiments were performed to study the effect of pH, ionic strengths, initial concentration, and contact time on OTC adsorption. The adsorbents were characterized using powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) before and after adsorption. Adsorption of OTC reached its maximum when solution pH increased up to 6 for 0.001 M ionic strength, above which adsorption decreased further when solution pH increased. Freundlich and Langmuir's models best fit the equilibrium data with a strong dependency on OTC adsorption capacity giving its maximum at 36 mg g−1. Binding is postulated for OTC adsorption on pristine kaolinite as a special case of Hill model with independent binding interaction of OTC adsorption onto the clay that affects the adjacent sites on the pristine kaolinite, in contrast with the adsorption of OTC on methoxy-modified kaolinite. Nitrogen peaks of the XPS spectra indicated changes in the oxidation states of C–N bonds in the N1s peaks by forming tertiary amide C–N and methoxy O–CH3 bonds which corroborated with the results from FTIR spectra. Removal efficiencies and spectroscopic results indicate that performance on methoxy-modified kaolinite is a promising modification on the clay for recovering antibiotics from wastewater.
AB - Kaolinite and methoxy-modified kaolinite were used as novel adsorbents for oxytetracycline (OTC) removal and recovery from aqueous media. Batch adsorption experiments were performed to study the effect of pH, ionic strengths, initial concentration, and contact time on OTC adsorption. The adsorbents were characterized using powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) before and after adsorption. Adsorption of OTC reached its maximum when solution pH increased up to 6 for 0.001 M ionic strength, above which adsorption decreased further when solution pH increased. Freundlich and Langmuir's models best fit the equilibrium data with a strong dependency on OTC adsorption capacity giving its maximum at 36 mg g−1. Binding is postulated for OTC adsorption on pristine kaolinite as a special case of Hill model with independent binding interaction of OTC adsorption onto the clay that affects the adjacent sites on the pristine kaolinite, in contrast with the adsorption of OTC on methoxy-modified kaolinite. Nitrogen peaks of the XPS spectra indicated changes in the oxidation states of C–N bonds in the N1s peaks by forming tertiary amide C–N and methoxy O–CH3 bonds which corroborated with the results from FTIR spectra. Removal efficiencies and spectroscopic results indicate that performance on methoxy-modified kaolinite is a promising modification on the clay for recovering antibiotics from wastewater.
KW - Clay
KW - Emerging contaminants
KW - Environmental remediation
KW - Methoxy-surface modification
KW - Wastewater
UR - http://www.scopus.com/inward/record.url?scp=85102268407&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2021.130079
DO - 10.1016/j.chemosphere.2021.130079
M3 - Article
C2 - 33721631
AN - SCOPUS:85102268407
SN - 0045-6535
VL - 276
JO - Chemosphere
JF - Chemosphere
M1 - 130079
ER -
