Separations (Aug 2023)

Removal of Pb(II) from Aqueous Solution and Adsorption Kinetics of Corn Stalk Biochar

  • Wenling Yang,
  • Chaoyang Lu,
  • Bo Liang,
  • Chaohui Yin,
  • Gao Lei,
  • Baitao Wang,
  • Xiaokai Zhou,
  • Jing Zhen,
  • Shujing Quan,
  • Yanyan Jing

DOI
https://doi.org/10.3390/separations10080438
Journal volume & issue
Vol. 10, no. 8
p. 438

Abstract

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In this work, the Pb adsorption and removal ability of biochar from simulated Pb(II)-contaminated wastewater, adsorption isotherms, kinetics, and thermodynamics were studied. Adsorption characteristics of biochar on Pb(II) were analyzed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope with energy dispersive spectrometer (SEM-EDS). The influence of the pH of the solution, the contact time, and the biochar dose on the removal of Pb(II) were investigated by single-factor design and response surface analysis. With the increase in biochar dose from 2 g/L to 4 g/L in wastewater, the Pb(II) amount adsorbed on biochar reduced from 21.3 mg/g to 17.5 mg/g. A weakly acidic environment was more conducive to the ligand exchange between Pb(II) ions and biochar. Pb(II) adsorption kinetics of biochar showed that the Pseudo-first-order model was more suitable than other employed models to describe the adsorption process. During the isothermal adsorption process, Langmuir and Freundlich’s isotherms fitted the adsorption data very well (R2 > 96%). The Pb (II) adsorption onto biochar was spontaneous in the specified temperature range (298–318 K) and the process was exothermic. Simultaneously, the optimal conditions were a pH of 5, a contact time of 255 min, and a biochar dose of 3 g/L, under which the maximum predicted Pb(II) removal efficiency was 91.52%.

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