This study examined conditions that mimic oxidative processes of biomass chars during formation and weathering in the environment. A maple char prepared at the single heat treatment temperature of 500 °C for 2 h was exposed to different thermal oxidation conditions or accelerated oxidative aging conditions prior to sorption of naphthalene or the dication paraquat. Strong chemical oxidation (SCO) was included for comparison. Thermal oxidation caused micropore reaming, with ambient oxidation and SCO much less so. All oxidative treatments incorporated O, acidity, and cation exchange capacity (CEC). Thermal incorporation of O was a function of headspace O₂ concentration and reached a maximum at 350 °C due to the opposing process of burn-off. The CEC was linearly correlated with O/C, but the positive intercept together with nuclear magnetic resonance data signifies that, compared to O groups derived by anoxic pyrolysis, O acquired through oxidation by thermal or ambient routes contributes more to the CEC. Thermal oxidation increased the naphthalene sorption coefficient, the characteristic energy of sorption, and the uptake rate due to pore reaming. By contrast, ambient oxidation (and SCO) suppressed naphthalene sorption by creating a more hydrophilic surface. Paraquat sorption capacity was predicted by an equation that includes a CEC² term due to bidentate interaction with pairs of charges, predominating over monodentate interaction, plus a term for the capacity of naphthalene as a reference representing nonspecific driving forces.

中文翻译：

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热氧化或环境风化对生物质炭的物理化学变化及其对疏水性和阳离子化合物吸附的影响

这项研究检查了在环境中形成和风化过程中模拟生物质炭氧化过程的条件。在吸附萘或双阳离子百草枯之前，将在 500°C 的单一热处理温度下制备 2 小时的枫木炭暴露于不同的热氧化条件或加速氧化老化条件。包括强化学氧化 (SCO) 以进行比较。热氧化会导致微孔铰孔，环境氧化和 SCO 的影响要小得多。所有氧化处理都包含 O、酸度和阳离子交换容量 (CEC)。O 的热结合是顶空 O ₂的函数由于相反的燃烧过程，浓度并在 350°C 时达到最大值。CEC 与 O/C 呈线性相关，但正截距和核磁共振数据表明，与缺氧热解产生的 O 基团相比，通过热或环境途径氧化获得的 O 对 CEC 的贡献更大。热氧化增加了萘吸附系数、吸附特征能和由于孔扩孔引起的吸收率。相比之下，环境氧化（和 SCO）通过产生更亲水的表面来抑制萘吸附。百草枯的吸附能力是通过一个包含 CEC ² 由于与成对电荷的双齿相互作用而产生的术语，在单齿相互作用中占主导地位，加上萘的容量作为代表非特定驱动力的参考。