Enhanced adsorption of sulfonated lignite with hierarchical porous-structure of MgAl-layered double hydroxide

Sulfonated lignite (SL) is extensively utilized in petroleum exploration; however, its effective removal from wastewater poses a significant challenge. China’s environmental protection department has classified it as a regulated oilfield chemical. In this study, hierarchically porous layered double...

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Bibliographic Details
Published in:Desalination and water treatment 2023-11, Vol.312, p.166-176
Main Authors: Bai, Bingbing, Yang, Chenye, Huang, Chen, Yu, Tao, Chen, Gang, Tang, Ying
Format: Article
Language:English
Subjects:
Adsorption
Hierarchically porous hydrotalcite
Soft template
Sulfonated lignite
Wastewater
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Summary:Sulfonated lignite (SL) is extensively utilized in petroleum exploration; however, its effective removal from wastewater poses a significant challenge. China’s environmental protection department has classified it as a regulated oilfield chemical. In this study, hierarchically porous layered double hydroxide nanoparticles was prepared based on the soft template of cetyltrimethylammonium chlo-ride and salicylic acid under hydrothermal condition. The effects of surfactant concentrations on the physical properties of the obtained adsorbents have been investigated by using X-ray powder diffraction, scanning electron microscopy, Brunauer–Emmett–Teller, and Fourier-transform infrared spectroscopy characterizations. It was found that three-dimensionally hydrotalcite nanosheets attached uniformly on the surface of soft template, generating higher crystallization and large specific area. Furthermore, the adsorption capacity of the material to SL was investigated to evaluate its application for the treatment of oilfield wastewater. The maximum adsorption capacity was equal to 854.70 mg/g at 298 K and pH of 7, which is significantly higher than the adsorption capacity of ordinary hydrotalcite (56.3 mg/g). The adsorption reaction followed the pseudo-second- order kinetics as well as the Freundlich isotherm model. Moreover, thermodynamic investigations showed that adsorption exhibits exothermic characteristics. After three adsorption–desorption cycles, hierarchically porous hydrotalcite nanoparticles still exhibit a high adsorption capacity of up to 187.7 mg/g. Anion exchange and electrostatic attraction were considered as the main adsorption mechanisms.
ISSN:1944-3986
DOI:10.5004/dwt.2023.29937