Department of Civil and Environmental Engineering, School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, China; Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Beijing Jiaotong University, Beijing, 100044, China; Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
Department of Civil and Environmental Engineering, School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, China.
Chemosphere. 2022 Jan;287(Pt 3):132239. doi: 10.1016/j.chemosphere.2021.132239. Epub 2021 Sep 13.
The sorption isotherms of polychlorinated biphenyls (PCBs) on carbons (coal based activated carbon named AC and hardwood derived biochar named BC) and natural organic matter (NOM) loaded carbons were examined and carbon-water partition coefficients (K) were calculated. The purpose was to accurately predict the effectiveness of in-situ carbon treatments on the sediment impacted with hydrophobic organic chemicals (HOCs). For 1 month sorption, AC K values were significantly higher than BC, corresponding to the much larger surface area (particularly in mesopores) for AC. BC K values were correlated with PCB total surface area (TSA) and octanol-water partition coefficient (logK). After loading with NOM, AC adsorption to PCBs strongly reduced and the fitted Freundlich exponents (n) decreased with increasing NOM level. However, NOM loading slightly impacted BC sorption and exhibited an opposite effect on BC n values. It is illustrated that the sorption mechanisms are different between AC and BC thereby the influences of NOM on sorption characteristics differ vastly. As the sorption time increased from 1 month to 6 months, an increase is observed in BC sorption extent but simultaneously NOM reduction effect on BC sorption increases, implying that more accurately evaluating BC application as an in-situ sorbent amendment for HOC impacted sediment need further investigation. On the contrary, AC adsorption attenuation caused by NOM coating greatly decreases over time, encouraging AC application as a sediment amendment.
研究了多氯联苯（PCBs）在碳（煤基活性炭 AC 和硬木衍生生物炭 BC）和负载天然有机物（NOM）的碳上的吸附等温线，并计算了碳-水分配系数（K）。目的是准确预测原位碳处理对受疏水性有机化学品（HOCs）影响的沉积物的有效性。在 1 个月的吸附时间内，AC 的 K 值明显高于 BC，这与 AC 的更大表面积（特别是中孔）相对应。BC 的 K 值与 PCB 的总表面积（TSA）和辛醇-水分配系数（logK）相关。负载 NOM 后，AC 对 PCBs 的吸附作用明显减弱，拟合的 Freundlich 指数（n）随 NOM 水平的增加而降低。然而，NOM 负载对 BC 的吸附影响较小，对 BC n 值表现出相反的影响。这表明 AC 和 BC 的吸附机制不同，因此 NOM 对吸附特性的影响有很大差异。随着吸附时间从 1 个月增加到 6 个月，BC 的吸附量增加，但同时 NOM 对 BC 吸附的减少作用也增加，这意味着需要进一步研究更准确地评估 BC 作为受 HOC 影响沉积物的原位吸附剂改良剂的应用。相反，由于 NOM 涂层导致 AC 吸附衰减随时间的推移而大大降低，这鼓励将 AC 作为沉积物改良剂应用。
