Abstract Polycyclic aromatic hydrocarbons (PAHs) sorption-desorption in soils, as influenced by soils' physicochemical conditions, control the extent of PAHs translocation, persistence and bioavailability. Though mono-PAHs sorption on soils reports abound, co-occurrence of PAHs in the environment is common and affects individual PAHs sorption characteristics competitively or cooperatively. Besides, most reports were not on sub-Saharan soils. Hence, the batch experiments to study simultaneous sorption–desorption of pyrene and fluorene on five soils, with varying minerals contents, from different sub-Saharan agro-ecological zones. Sorption was concentration dependent and increased as concentration. There was higher preference for pyrene, though lower sorption than in mono-PAHs solutions. Irrespective of competition, soil organic matter (≥ 4.5%) caused high pyrene sorption similar to mono-PAHs sorption. At 25 °C, pyrene had lower hysteresis in simultaneous desorption compared to mono-PAHs, while higher hysteresis was observed in fluorene for all soils. Simultaneous sorption was higher at 40 than 25 °C and higher hysteresis exhibited as temperature increased in contrast to desorption at 25 °C. Isotherm model studies showed that simultaneous sorption of both PAHs were on heterogeneous surfaces and are composites of several linear and non-linear isotherms. Ultimately, soil constituents, PAHs concentration, competition for sorption sites, size and structural relationship play vital roles in simultaneous sorption on these soils. Risk of environmental contamination is higher for fluorene than pyrene during co-occurrence and likely so in the warmer and low organic matter soils of northern sub-Sahara.

中文翻译：

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撒哈拉以南非洲主要土壤矿物质上芘和芴的浓度依赖性和同步吸附和解吸

摘要 土壤中多环芳烃（PAHs）的吸附-解吸受土壤理化条件的影响，控制着PAHs易位、持久性和生物有效性的程度。尽管对土壤中单一多环芳烃的吸附报告比比皆是，但多环芳烃在环境中的共存很常见，并且会竞争或协同地影响单个多环芳烃的吸附特性。此外，大多数报告都不是关于撒哈拉以南的土壤。因此，分批实验研究芘和芴在来自不同撒哈拉以南农业生态区的具有不同矿物质含量的五种土壤上的同时吸附-解吸。吸附是浓度依赖性的，并且随着浓度的增加而增加。尽管比单多环芳烃溶液的吸附低，但对芘有更高的偏好。不考虑竞争，土壤有机质（≥ 4. 5%) 引起类似于单-PAHs 吸附的高芘吸附。在 25 °C 时，芘在同时解吸中的滞后比单-多环芳烃低，而在所有土壤中，芴的滞后更大。同时吸附在 40°C 时高于 25°C，并且与在 25°C 时解吸相比，随着温度升高表现出更高的滞后。等温线模型研究表明，两种多环芳烃同时吸附在异质表面上，并且是几种线性和非线性等温线的复合物。最终，土壤成分、多环芳烃浓度、对吸附位点的竞争、大小和结构关系在这些土壤上的同时吸附中起着至关重要的作用。