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- Title
生物炭去灰分对萘和1-萘酚的吸附动力学影响.
- Authors
张萌; 吕耀斌; 朱一滔; 罗雅琪; 李威; 李萍萍; 王喜龙
- Abstract
To elucidate the mineral effects of biochars on the sorption of organic pollutants (OPs), we investigated the sorption kinetics of naphthalene and 1-naphthol on both pristine and deashed wheat straw-derived biochars obtained at different temperatures. The kinetics data better fitted with the pseudo second-order model, followed by the two-compartment model in comparison with the pseudo first-order model. Deashing treatment increased the aromatic carbon content of biochars, thereby enhancing their p-p and hydrophobic interactions with the two tested compounds. Deashing also reduced the surface polarity of biochars, especially the O-alkyl polar components, thereby enhancing the accessibility of their hydrophobic carbon domains, mainly the aromatic carbon components. Hence, the equilibrium sorption capacity (Qe) of naphthalene and 1-naphthol increased. Reducing the external exposure of polar functional groups by mineral removal enhanced the diffusion of naphthalene molecules toward the hydrophobic sorption sites, thereby increasing its sorption rate constant for the fast-sorbing fraction on biochars (kfast). However, the substituted polar —OH group in 1-naphthol was able to interact with polar groups on biochars or mineral O-containing surfaces via H-bond that greatly contributed to its fast sorption. The H-bonding was weakened after deashing, which could account for a higher kfast value of 1-naphthol by the original biochar than that of its corresponding deashed one. Deashing increased the amount of aromatic components and porous structures in biochars, which were responsible for the slow sorption of naphthalene and 1-naphthol, resulting in increased contributions of the slowly sorbing fraction to the total sorption (fslow). The increased condensation of organic carbon in deashed biochars hindered the diffusion of naphthalene and 1- naphthol molecules into biochars. Additionally, increasing the surface area and porosity of biochars prolonged the sorption equilibrium time, and thus the rate constants for the slow sorption fraction (kslow)of both compounds decreased. The results of this work could help us better understand the effect of minerals, chemical composition, and spatial arrangement of polar functionalities of biochars on the sorption of OPs and predict their fate in soils after biochar application
- Subjects
SPATIAL arrangement; HYDROPHOBIC interactions; NAPHTHOL; NAPHTHALENE; BIOCHAR; SORPTION
- Publication
Journal of Agro-Environment Science, 2020, Vol 39, Issue 12, p2806
- ISSN
1672-2043
- Publication type
Article
- DOI
10.11654/jaes.2020-0708