Per-and polyfluoroalkyl substances (PFAS), a large class of synthesized chemicals, are persistent in nature and generally recalcitrant to conventional chemical and biological treatment. Adsorption is considered an economical and practical method for PFAS treatment. Layered double hydroxides (LDHs) represent a promising class of mineral-based adsorbents for PFAS removal because of the highly positive charge of their structural layers. In this research, the performance of two representative LDHs with varied cation compositions, namely Zn-Al and Mg-Al LDHs, were investigated and compared for the removal of perfluorinated carboxylic acids (PFCAs) with an emphasis on perfluorooctanoic acid (PFOA). Zn-Al LDH showed high efficiency for the removal of medium- and long-chain PFCAs (i.e., C ≥ 7), and performed consistently better than Mg-Al LDH. Based on detailed adsorption kinetics and isotherm studies toward PFOA, Zn-Al LDH showed higher adsorption capacity, stronger adsorption affinity, and faster kinetics than Mg-Al LDH. Presence of natural organic matter had minimal impact on PFOA removal by Zn-Al LDH, but sulfate severely inhibited PFOA adsorption. Combined results of aqueous adsorption experiments and sorbent characterization suggested that electrostatic interactions may be the primary mechanism for PFOA adsorption onto LDHs. Our results suggested that cation composition of LDHs can have significant effect on the performance for PFCA removal.
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http://dx.doi.org/10.1016/j.chemosphere.2021.132297 | DOI Listing |
Langmuir
November 2024
School of Chemistry and Chemical Engineering, Jiangxi University of Science and Technology, No.86, Hongqi Ave., Ganzhou 341000, Jiangxi, China.
Different Zn/Al ratios of Cl intercalated ZnAl-layered double hydroxide (ZnAl-LDH) were prepared using the coprecipitation method, and their adsorption performance for Cu in aqueous solution was evaluated. The factors affecting adsorption properties, such as dosage, reaction time, and pH, were determined by adsorption experiments. Then, the adsorption kinetics and isotherm models were fitted to evaluate the adsorption mechanism.
View Article and Find Full Text PDFEnviron Res
December 2024
Laboratory of Applied Physical Chemistry, Faculty of Sciences Ibn Zohr University, BP 8106 Dakhla, 80060, Agadir, Morocco.
Environ Sci Pollut Res Int
October 2024
Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh.
In this study, Zn-Al-SO LDH-functionalized biochar was fabricated using the co-precipitation method. The biochar was synthesized from waste cow dung using a low-temperature pyrolysis process (300 °C). The materials were fully characterized by TGA, FTIR, EDS, SEM, and XRD analysis.
View Article and Find Full Text PDFRSC Adv
September 2024
Botany and Microbiology Department, Faculty of Science, Beni-Suef University Egypt
Layer double hydroxide (LDH) nanoparticles (NPs) have been applied to enhance plant growth and productivity. However, their effects on carbon and nitrogen metabolism of aromatic plants, are not well understood. Therefore, we investigated the impact of foliar application of Zn-Al LDH and Mg-Al LDH NPs (10 ppm) on the growth and metabolism of geranium plants.
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