Open AccessEthylenediaminetetraacetate functionalized MgFe layered double hydroxide/biochar composites for highly efficient adsorptive removal of lead ions from aqueous solutions
Author(s) -
Muhammad Amin,
A. A. Alazba,
Muhammad Shafiq
Publication year - 2022
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0265024
Subject(s) - adsorption , layered double hydroxides , biochar , aqueous solution , langmuir adsorption model , chemistry , fourier transform infrared spectroscopy , monolayer , langmuir , chemisorption , nuclear chemistry , hydroxide , chemical engineering , materials science , inorganic chemistry , organic chemistry , pyrolysis , biochemistry , engineering
The application of layered double hydroxides (LDHs) of MgFe and its composites with biochar of Eucalyptus camdulensis (Eb) and ethylenediaminetetraacetic acid (EDTA) was explored in a batch study to mitigate toxic lead ions (Pb 2+ ) from synthetic wastewater solutions. SEM images revealed that MgFe/LDH composites with Eb were successfully formed, while FTIR spectra confirmed the successful adsorption of Pb 2+ onto the MgFe/LDH and composite adsorbents. Batch equilibrium was attained after 60 min, then the adsorption capacity gradually increased. An increase in adsorption capacity (and a 60% decrease in the percentage removal) was observed by increasing the initial Pb 2+ concentration, and the highest value was 136 mg g -1 for MgFe/LDH-Eb_EDTA. A 50–60% increase in both the adsorption capacities and percent removal was seen in the pH range of 2–6. The second-order kinetic model had a nearly perfect fitting, suggesting that chemisorption was the mechanism controlling adsorption. The Langmuir isotherm model best presented the adsorption data, suggesting that the Pb 2+ adsorption was monolayer, and predicted a better affinity between the adsorbent surface and absorbed Pb 2+ for MgFe/LDH-Eb_EDTA in comparison to the other two adsorbents. The D–R isotherm suggested that the adsorption system was physical based on E values for all three adsorbents, while the Temkin isotherm model suggested that Pb 2+ adsorption was heterogeneous. Finally, the Sips and R–P isotherms predicted that the adsorption of Pb 2+ on the surface of the adsorbents was homogeneous and heterogeneous.