Sorption of bisphenol A, 17α-ethinyl estradiol and phenanthrene on thermally and hydrothermally produced biochars

Thermal and hydrothermal biochars were characterized, and adsorption of bisphenol A (BPA), 17α-ethinyl estradiol (EE2) and phenanthrene (Phen) was determined to investigate the sorption characteristic difference between the two types of biochars. Thermal biochars were composed mostly of aromatic moieties, with low H/C and O/C ratios as compared to hydrothermal ones having diverse functional groups. Single-point organic carbon-normalized distribution coefficients (logKOC) of EE2 and BPA of hydrothermal biochars were higher than thermal biochars, while Phen logKOC values were comparable among them. X-ray diffraction and solid state nuclear magnetic resonance results suggested that hydrothermal biochars consisted of more amorphous aliphatic-C, possibly being responsible for their high sorption capacity of Phen. This study demonstrated that hydrothermal biochars could adsorb a wider spectrum of both polar and nonpolar organic contaminants than thermally produced biochars, suggesting that hydrothermal biochar derived from poultry and animal waste is a potential sorbent for agricultural and environmental applications.

► A new way (hydrothermal) to produce biochar from organic waste/biomass was unitized.
► Hydrothermal biochars had more diverse structures than the thermal ones.
► Hydrothermal biochar had higher or similar sorption of organic contaminants than thermal ones.
► Hydrothermally produced biochars would be preferred in soil application.
► Less energy is needed to carbonize wet feedstock using hydrothermal method.