Abstract：
Abundant biochar colloids (BCs) produced from a wide range of feedstocks, resulting from forest fires, agricultural production, and environmental restoration, exhibit varying aggregation behaviors influenced by feedstock type and natural organic matter. However, the impact of natural organic matter on the colloidal stability of BCs derived from different feedstocks remains poorly understood. In this study, six selected biochars were derived from various feedstocks as follows: sewage sludge (SS), rice husk (RH), oil seed rape straw pellets (OSR), wheat straw pellets (WS), miscanthus straw pellets (MS) and softwood pellets (SW). The colloidal stability of BCs, with the exogenous addition of organic matter, was further determined. The order of critical coagulation concentrations (CCCs) of BCs with the presence of humic acid (HA) was as follows: RH (989.48 mM) < MS (1084.69 mM) < SS (1149.76 mM) < WS (1338.99 mM) < OSR (2402.98 mM) < SW (3151.32 mM). This order was significantly positively correlated with the specific surface area and negatively correlated with the ash content of the bulk biochar. Compared to HA, bovine serum albumin (BSA) more effectively inhibited the aggregation behavior of BCs due to steric hindrance. The initial aggregation rate constant (k) of BCs at 3000 mM NaCl was as follows: MS (0.238 nm/s) > OSR (0.142 nm/s) > WS (0.128 nm/s) > SS (0.126 nm/s) > RH (0.118 nm/s) > SW (0.112 nm/s). The stabilizing effects of BSA on biochar colloids were independent of the physicochemical properties of bulk biochar. In the presence of BSA, a thin layer of protein corona significantly enhanced the stability of biochar colloids, particularly the BCs derived from MS. Our results underscore the importance of considering feedstock resources and natural organic matter type when assessing the aggregation and potential risks of BCs in aquatic systems.
摘要：
丰富的生物炭胶体（BCs）生产的范围广泛的原料，由于森林火灾，农业生产,和环境恢复，表现出受原料类型和天然有机物影响的不同聚集行为。然而,天然有机物对来自不同原料的BCs的胶体稳定性的影响仍然知之甚少。在这项研究中,六种选定的生物炭来自各种原料，如下：污水污泥(SS)，稻壳（RH），油菜籽秸秆颗粒（OSR），小麦秸秆颗粒(WS)，芒草粒料(MS)和软木粒料(SW)。BCs的胶体稳定性，随着有机物的外源添加，进一步确定。在腐殖酸(HA)存在下,BC的临界凝固浓度(CCC)的顺序如下:RH(989.48mM)OSR(0.142nm/s)>WS(0.128nm/s)>SS(0.126nm/s)>RH(0.118nm/s)>SW(0.112nm/s)。BSA对生物炭胶体的稳定作用与散装生物炭的理化性质无关。在BSA存在的情况下,一层薄薄的蛋白质电晕显着增强了生物炭胶体的稳定性，特别是从MS衍生的BCs我们的结果强调了在评估水生系统中BCs的聚集和潜在风险时，考虑原料资源和天然有机物类型的重要性。
