Abstract
The potential application of biochar in water treatment is attracting interest due to its sustainability and low production cost. In the present study, H3PO4-modified biochar (H-PBC), ethylenediaminetetraacetic acid-modified biochar (E-PBC), and NaOH-modified biochar (O-PBC) were prepared for Ni(II) and Pb(II) adsorption in an aqueous solution. Scanning electron microscopy (SEM), X-ray diffraction analysis, Brunauer–Emmett–Teller analysis, and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize the as-obtained samples, and their capacities for Ni(II) and Pb(II) adsorption were determined. SEM showed that H-PBC retained the hierarchical porous structure of pristine biochar, and projections were observed on its surface. FT-IR showed that H-PBC possessed abundant oxygen-containing and phosphorus-containing functional groups on the surface. H-PBC, E-PBC, and O-PBC all exhibited excellent performance at Ni(II) and Pb(II) adsorption with qmax values of 64.94 mg/g, 47.17 mg/g, and 60.24 mg/g, and 243.90 mg/g, 156.25 mg/g, and 192.31 mg/g, respectively, which were significantly higher than the adsorption capacity (19.80 mg/g and 38.31 mg/g) of pristine biochar. Pseudo-second order models suggested that the adsorption process was controlled by chemical adsorption. Regeneration analysis showed that H-PBC had superior reusability characteristics. H-PBC had a greater adsorption capacity than other adsorbents due to its large specific surface area, and abundant oxygen-containing and phosphorus-containing functional groups. The results obtained in this study suggest that H-PBC is a promising adsorbent for the removal of heavy metals from aqueous solutions.
Comparative Study of Biochar Modified with Different Functional Groups for Efficient Removal of Pb(II) and Ni(II)
