|Wang, Ziying - Beijing Normal University|
|Han, Lanfang - Beijing Normal University|
|Sun, Ke - Beijing Normal University|
|Jin, Jie - Beijing Normal University|
|Libra, Judy - Leibniz Institute|
|Liu, Xitao - Beijing Normal University|
|Xing, Boashan - University Of Massachusetts|
Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/11/2015
Publication Date: 9/15/2015
Publication URL: http://dx.doi.org/10.1016/j.chemosphere.2015.08.042
Citation: Wang, Z., Han, L., Sun, K., Jin, J., Ro, K.S., Libra, J.A., Liu, X., Xing, B. 2015. Sorption of four hydrophobic organic contaminants by biochars derived from maize straw, wood dust and swine manure at different pyrolytic temperatures. Chemosphere. 144:285-291. doi: org/10.1016/j.chemosphere.2015.08.042.
Interpretive Summary: Three types of biochars were evaluated for their ability to remove a non-ionic and non-volatile herbicide (ACE), a widely used plasticizer (DBP), one of most frequently detected endocrine disruptor (EE2), and a commonly researched aromatic compound (PHE). The three biochars were made from pyrolyzing maize straw, pine wood dust, and swine manures. Among the three biochars, the swine manure based biochar showed higher sorption capacity than other two plant biomass based biochars. The results of this study contribute to better understanding of the effect of feedstocks on the sorption capacity toward to environmental contaminants.
Technical Abstract: To study the interactions between biochars and hydrophobic organic compounds (HOCs), the adsorption of HOCs with varied physical-chemical properties on biochars produced from three feedstock sources (maize straw (MABs), pine wood dust (WDBs) and swine manure (SWBs)) was evaluated. The biochars produced at seven heat treatment temperatures (HTTs) were characterized and their sorption isotherms of acetochlor (ACE), dibutyl phthalate (DBP), 17 alpha-ethynyl estradiol (EE2) and phenanthrene (PHE) were determined. The hydrogen carbon (H/C) ratio and bulk polarity of these biochars all declined with increasing HTT while the aromaticity and carbon dioxide (CO2)-surface area (CO2-SA) rose. In general, the nonlinearity coefficients (n) of sorption isotherms of each given sorbate were negatively related to their organic carbon (OC)-normalized CO2-SA (CO2-SA/OC) of biochars, showing the dominant role of pore-filling mechanism in the nonlinear sorption behavior of these sorbates. Among the three kinds of biochars, soil organic carbon-water partition coefficient (logKoc) values for SWBs were the highest, possibly due to their higher ash contents. Additionally, MABs tended to have relatively greater logKoc values than WDBs when the HTTs were below 450 degree Celsius (°C), probably resulting from the higher CO2-SA, ash contents as well as aromaticity of MABs. H-bonding may regulate the sorption of those biochars obtained at relatively low HTTs (= 400 °C), while aromatic C affects the sorption of biochars at high HTTs through pi-pi (p-p) interaction. Results of this work aid to deepen our understanding of the sorption mechanisms, which is pivotal to wise utilization of biochars as sorbents for hazardous organic compounds.