Comparative study for microcystin-LR sorption onto biochars produced from various plant- and animal-wastes at different pyrolysis temperatures: Influencing mechanisms of biochar properties

Diverse biochars produced from various feedstock sources (i.e., plant- and animal-wastes) at different pyrolysis temperatures (PTs) were characterized for their structural properties and sorption behaviors of aqueous microcystin-LR (MC-LR). Results indicated that MC-LR sorption capability of tested biochars varied as a function of biochar structural properties. Sorption mechanisms involved electrostatic attraction, pore-filling, hydrogen-bonding effect and π-π electron donor-acceptor interaction, but predominant mechanisms varied for different biochars. At the same PT (300 or 600°C), chicken manure-derived biochars (CMBs) exhibited stronger MC-LR sorption than others, with sorption coefficient (K_d) of 6.321-15.529Lg^-1 and 6.354-8.294Lg^-1 at aqueous equilibrium concentration (C_e) of 40 and 200μgL^-1, respectively. Higher mesoporosity, the point of zero charge and total surface groups concentration related to higher ash content of CMBs, which might be indispensable for enhancing MC-LR sorption. This study suggested that CMBs have great potential as low-cost sustainable sorbents to abate MC-LR contamination.