The presence of arsenic (As) and lead (Pb) in water above tolerable levels is a global concern, as both elements are extremely toxic and can compromise the health of millions of people. In this study, we evaluated biochars pyrolyzed at 350 (BC350) and 750 °C (BC750) and then modified with ferric chloride (FeCl₃) to remove As and Pb from water samples contaminated by mining activity. The use of FeCl₃-modified biochar was an efficient strategy to remove As and Pb from water. Sorption on biochars followed the pseudo-second-order kinetics, represented by two sorption speeds, being higher at the beginning of the reaction and falling over time. The modification with FeCl₃ increased the specific surface area, removed the dissolved organic carbon, and increased the capacity of BC350 to sorb Pb. These physical and chemical alterations of the biochar played a significant role in the sorption capacity and speed of As and Pb.

水中砷 (As) 和铅 (Pb) 的含量超过可接受水平是一个全球性的问题，因为这两种元素都具有剧毒，会危害数百万人的健康。在本研究中，我们评估了在 350 (BC350) 和 750 °C (BC750) 下热解，然后用氯化铁 (FeCl ₃ )改性以去除受采矿活动污染的水样中的 As 和 Pb 的生物炭。使用 FeCl ₃改性的生物炭是从水中去除 As 和 Pb 的有效策略。生物炭的吸附遵循伪二级动力学，由两种吸附速度表示，在反应开始时较高，随着时间的推移而下降。FeCl ₃改性增加了比表面积，去除了溶解的有机碳，并增加了 BC350 吸附 Pb 的能力。生物炭的这些物理和化学变化对 As 和 Pb 的吸附能力和速度起到了重要作用。