|Han, Lanfang - Beijing Normal University|
|Sun, Ke - Beijing Normal University|
|Wang, Ziying - Beijing Normal University|
|Sun, Haoran - Beijing Normal University|
|Libra, Judy - Leibniz Institute|
|Xing, Baoshan - University Of Massachusetts|
Submitted to: Journal of Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2016
Publication Date: 11/20/2016
Citation: Han, L., Ro, K.S., Sun, K., Wang, Z., Sun, H., Libra, J.A., Xing, B. 2016. New evidence for high sorption capacity of hydrochar for hydrophobic organic pollutants. Journal of Environmental Science and Technology. doi: 10.1021/acs.est.6b02401.
Interpretive Summary: Two types of swine manure biochars were evaluated for their ability to remove pharmaceuticals and personal care products (PPCPs) and a polycyclic aromatic hydrocarbon pyrene (PYE) from water. Pyrochars were produced from dry pyrolysis of swine solids at three temperatures (250, 450, and 600 degree Celsius); hydrochar was produced from wet pyrolysis of swine slurry at 250 Celsius. We found that pyrochars were only effective for removing non-polar organic pollutants. However, hydrochar showed high potential to be used to remove both polar and non-polar pollutants due to its diverse surface functionalities. This research not only indicates that hydrochars are promising sorbents for environmental applications, but also casts new light on mechanisms underlying the high sorption capacity of hydrochars for both nonpolar and polar organic pollutants.
Technical Abstract: This study investigated the sorption potential of hydrochars, produced from hydrothermally carbonizing livestock wastes, towards organic pollutants (OPs) with a wide range of hydrophobicity, and compared their sorption capacity with that of pyrochars obtained from conventional dry pyrolysis from the same feedstock. Results of state of art instrumental analyses demonstrated that organic carbon (OC) of hydrochars mainly consisted of amorphous alkyl and aryl carbon (C). Hydrochars exhibited consistently higher soil-water partition coefficient (Koc) of both nonpolar and polar OPs than pyrochars. This, combined with the significantly less energy required for the hydrothermal process, suggests that hydrothermal conversion of surplus livestock waste into value-added sorbents could be an alternative manure management strategy. Moreover, the hydrochars Koc values were practically unchanged after the removal of amorphous aromatic C, implying that amorphous aromatic C played a comparable role in the high sorption capacity of hydrochars compared to amorphous alkyl C. It was thus concluded that the dominant amorphous C associated with both alkyl and aryl moieties within hydrochars explained their high sorption capacity for OPs. This research not only indicates that hydrochars are promising sorbents for environmental applications, but also casts new light on mechanisms underlying the high sorption capacity of hydrochars for both nonpolar and polar OPs.