Black carbon (BC) exhibits promising potential as a sediment amendment owing to its commendable adsorption capacity for hydrophobic organic contaminants (HOCs), thereby resulting in HOC-laden sediments. Desorption kinetic studies play a crucial role in comprehending the release potential of HOCs from BC-sediment systems. Although the adsorption capacity of BC for HOCs has been found to decrease with aging, there is limited research on its impact on HOC desorption kinetics. In this study, BCs derived from agricultural waste (rice straw carbon, RC) and industrial waste (fly ash carbon, FC), respectively, were used to investigate the desorption kinetics of nonylphenol (NP). Additionally, a predictive model was established using the fitting parameters obtained from the modified two-domain model. The results showed that desorption of NP was divided into three fractions: rapid fraction (F_rap), slow fraction (F_slow) and resistant fraction (F_r). BCs significantly decreased, while ageing increased the desorption amount and rate of NP. The performance of RC in controlling NP release was superior to that of FC. The predicted values calculated by the established model exhibit significant positive correlations with the measured values (p < 0.01). Additionally, the correlation analysis between sorption sites and desorption fractions revealed that the concentration of NP in the desorbing fraction was nearly equivalent to that of NP in partition sites within aged sediment/FC-sediment systems. However, the aged RC-sediment systems do not conform well to this rule. In other words, the estimation of NP release risk from sediments with a strong adsorbent would be overestimated, if F_rap + F_solw is considered equivalent to the desorbing fraction.

中文翻译：

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老化过程对黑炭沉积物系统中壬基酚解吸的影响：运动机制和建模研究

黑碳（BC）由于其对疏水性有机污染物（HOC）具有值得称赞的吸附能力，因此在沉积物改良方面表现出巨大的潜力，从而产生富含 HOC 的沉积物。解吸动力学研究在理解碳化物沉积物系统中 HOC 的释放潜力方面发挥着至关重要的作用。尽管已经发现BC对HOC的吸附能力随着老化而降低，但对其对HOC解吸动力学影响的研究有限。在这项研究中，分别使用来自农业废物（稻草碳，RC）和工业废物（飞灰碳，FC）的BC来研究壬基酚（NP）的解吸动力学。此外，使用从修改的两域模型获得的拟合参数建立了预测模型。结果表明，NP的解吸分为三个部分：快速部分（Frap）、缓慢部分（_{Fslow ）}和抵抗部分（_Fr）。 BCs显着下降，而老化则增加了NP的解吸量和速率。 RC在控制NP释放方面的性能优于FC。通过建立的模型计算的预测值与测量值呈现显着的正相关性（p <0.01）。此外，吸附位点和解吸部分之间的相关性分析表明，解吸部分中的NP浓度几乎与老化沉积物/FC-沉积物系统中的分配位点中的NP浓度相同。然而，老化的 RC 沉积系统不太符合这一规则。换句话说，如果F _rap + F _solw被认为等于解吸分数，则对具有强吸附剂的沉积物的 NP 释放风险的估计将会被高估。