O, N-doped porous biochar by air oxidation for enhancing heavy metal removal: The role of O, N functional groups.

Autor: Dinh VC; Faculty of Environmental Engineering, Hanoi University of Civil Engineering, 55 Giai Phong, Hai Ba Trung, Hanoi, 100000, Viet Nam. Electronic address: cuongdv@nuce.edu.vn., Hou CH; Graduate Institute of Environmental Engineering, National Taiwan University, No. 1, Sec. 4. Roosevelt Rd, Taipei, 10617, Taiwan; Research Center for Future Earth, National Taiwan University, No. 1, Sec. 4. Roosevelt Rd, Taipei, 10617, Taiwan., Dao TN; Faculty of Economics and Construction Management, Hanoi University of Civil Engineering, 55 Giai Phong, Hai Ba Trung, Hanoi, 100000, Viet Nam.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2022 Apr; Vol. 293, pp. 133622. Date of Electronic Publication: 2022 Jan 13.
DOI: 10.1016/j.chemosphere.2022.133622
Abstrakt: Oxygen- and nitrogen-doped porous oxidized biochar (O,N-doped OBC) was fabricated in this study. Biochar (BC) can be enriched in surface functional groups (O and N) and the porosity can be improved by a simple, convenient and green procedure. BC was oxidized at 200 °C in an air atmosphere with quality control via oxidation time changes. As the oxidation time increased, the O and N contents and porosity of the materials improved. After 1.5 h of oxidation, the O and N contents of O,N-doped OBC-1.5 were 54.4% and 3.9%, higher than those of BC, which were 33.4% and 1.8%, respectively. The specific surface area and pore volume of O,N-doped OBC-1.5 were 88.5 m 2  g -1 and 0.07 cm 3  g -1 , respectively, which were greater than those of BC. The improved surface functionality and porosity resulted in an increased heavy metal removal efficiency. As a result, the maximum adsorption capacity of Cu(II) by O,N-doped OBC was 23.32 mg L -1 , which was twofold higher than that of pristine BC. Additionally, for a multiple ion solution, O,N-doped OBC-1.5 showed a greater adsorption behavior toward Cu(II) than Zn(II) and Ni(II). In a batch experiment, the concentration of Cu(II) decreased 92.3% after 90 min. In a filtration experiment, the O,N-doped OBC-based filter achieved a Cu(II) removal capacity of 12.90 mg g -1 and breakthrough time after 250 min. Importantly, the chemical mechanism was mainly governed by monolayer adsorption of Cu(II) onto a homogeneous surface of O,N-doped OBC-1.5. Surface complexation and electrostatic attraction were considered to be the chemical mechanisms governing the adsorption process.
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Databáze: MEDLINE
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