Abstract The properties of rice husk biochar during the ageing process in soil and the resulting impacts on sorption capacity with respect to Cu(ii) were assessed. Rice husk-derived biochar was placed in fabric bags and buried in a plastic incubator filled with soil for 0–240 d. The aged biochar was then characterised and its sorption capacity compared with control (unaged) biochar in batch sorption experiments. The structural composition and morphology of the biochar before and after ageing were analysed based on element composition, scanning electron microscopy (SEM) coupled with energy X-ray dispersive spectroscopy (EDS), diffuse reflectance infrared Fourier transform infrared spectroscopy (DRIFTS), and X-ray photoelectron spectroscopy (XPS). The concentration of O, atomic O/C ratios, and carboxyl and hydroxyl functional groups increased at the surface of the biochar during ageing, which together indicated oxidation. Within the biochar particles, O/C ratios progressively increased towards their outer surfaces. Furthermore, ageing for more than 120 d facilitated Cu(ii) sorption as oxygen-containing groups were able to develop. The maximum adsorption capacity (q m) of biochar increased by 1.24 ∼ 1.32 times after ageing in the soil for 240 d. It is suggested that biochar surface properties were gradually altered during environmental exposure and the aged rice husk biochar showed increased performance in Cu(ii) adsorption. However, the performance of aged biochar as a soil remediator or conditioner will be affected by the ageing process and interactions among different soil components. As such, further research is required to evaluate these complex effects.

中文翻译：

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老化对稻壳生物炭在土壤中表面特征和Cu(ii)吸附行为的影响

摘要 评估了稻壳生物炭在土壤中老化过程中的特性及其对 Cu(ii) 吸附能力的影响。将稻壳衍生的生物炭放入织物袋中，并埋在装有土壤的塑料培养箱中 0-240 天。然后在批量吸附实验中对老化的生物炭进行表征，并将其吸附能力与对照（未老化）生物炭进行比较。基于元素组成、扫描电子显微镜(SEM)结合能量X射线色散光谱(EDS)、漫反射红外傅里叶变换红外光谱(DRIFTS)和X射线光谱分析了老化前后生物炭的结构组成和形貌。射线光电子能谱 (XPS)。O 的浓度，原子 O/C 比，在老化过程中，生物炭表面的羧基和羟基官能团增加，这共同表明氧化。在生物炭颗粒内，O/C 比朝着它们的外表面逐渐增加。此外，超过 120 天的老化促进了 Cu(ii) 的吸附，因为含氧基团能够发展。在土壤中老化 240 d 后，生物炭的最大吸附容量（qm）增加了 1.24 ～ 1.32 倍。这表明生物炭表面性质在环境暴露期间逐渐改变，老化的稻壳生物炭在 Cu(ii) 吸附方面表现出增强的性能。然而，老化生物炭作为土壤修复剂或调节剂的性能会受到老化过程和不同土壤成分之间相互作用的影响。因此，