Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China.
School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
Environ Sci Pollut Res Int. 2021 Jan;28(2):1574-1586. doi: 10.1007/s11356-020-10606-5. Epub 2020 Aug 26.
Co-transport of biochar (BC) colloids with coexisting organic contaminants (OCs) in soil involves complex interactions among BC colloids, OCs, and soil particles, which is significant for the environmental application and risk assessment of BC and yet has not been well addressed. This study explored co-transports of three typical OCs (i.e., phenanthrene (PHN), atrazine (ATZ), and oxytetracycline (OTC)) and BC colloids obtained from bulk BCs with different charring temperatures (200-700 °C) and particle sizes (250 nm, 500 nm, and 1 μm) in a soil column of 9 cm in height. Considerable transport of BC colloids alone was observed and the maximum breakthrough concentration (C/C) increased from 0.08 to 0.77 as the charring temperature decreased from 700 to 200 °C. The mobilities of PHN, OTC, and ATZ alone were very low but were greatly increased by co-transports with BC colloids, and their maximum C/C values were within 0.05-0.33, 0.03-0.44, and 0.05-0.62, respectively, in the absence and presence of various BC colloids. The enhancement effect of BC colloids on the OC transport decreased with increasing charring temperature or particle size of BC colloids. BC colloids mainly acted as a vehicle to facilitate the transport of OCs, and dissolved organic carbon from BC colloids also contributed to the increased mobility of OCs in dissolved form. These findings provide new insights into co-transport of BC colloids and contaminants in soil.
生物炭胶体与共存有机污染物（OCs）在土壤中的共运移涉及生物炭胶体、OCs 和土壤颗粒之间的复杂相互作用，这对于生物炭的环境应用和风险评估具有重要意义，但尚未得到很好的解决。本研究探讨了三种典型 OCs（即菲（PHN）、莠去津（ATZ）和土霉素（OTC））和生物炭胶体在 9 cm 高土壤柱中的共运移，这些生物炭胶体是由不同热解温度（200-700°C）和粒径（250nm、500nm 和 1μm）的原始生物炭获得的。单独运输生物炭胶体时，观察到相当大的运输量，最大突破浓度（C/C）从 0.08 增加到 0.77，随着热解温度从 700°C 降低到 200°C。PHN、OTC 和 ATZ 单独的迁移率非常低，但与生物炭胶体共运移时大大增加，其最大 C/C 值在 0.05-0.33、0.03-0.44 和 0.05-0.62 之间，在不存在和存在各种生物炭胶体的情况下。随着生物炭胶体热解温度或粒径的增加，生物炭胶体对 OC 运移的增强效应降低。生物炭胶体主要作为一种载体来促进 OCs 的运移，并且来自生物炭胶体的溶解有机碳也有助于增加溶解形式的 OCs 的迁移率。这些发现为生物炭胶体和污染物在土壤中的共运移提供了新的见解。
