Biochar is a beneficial soil amendment but the changes in its surface properties during the aging process, especially the oxygen-containing functional groups and the associated adsorption behaviors, are not well documented. In this paper, the aged wheat straw biochar was simulated by chemical oxidation with HNO₃-H₂SO₄ and NaOH-H₂O₂ systems. Characterization results showed that carbon loss and oxygen incorporation ran throughout the aging process. Surface oxygen-containing functional groups were found to be increased in all treated biochars, especially for carboxyl. Much more developed mesopores were observed in aging biochar, specific surface area was increased by 126% for biochar treated with NaOH-H₂O₂, and 226% for biochar treated with 40% of HNO₃-H₂SO₄. Thermogravimetric analysis showed that the increasing oxygen-containing functional groups led to 14% and 30% mass loss by treating biochar with alkali and acid, respectively. The improved biochar surface through the increase of oxygen-containing functional groups enhanced the cadmium sorption capacity, and the sorption capacity increased by 21.2% in maximum. Roughed surface from oxidation was another reason for increasing cadmium adsorption. Results indicated that the adsorption performance of biochar on pollutant would be changed during aging process along with the changing surface properties.

生物炭是一种有益的土壤改良剂，但在老化过程中其表面性质的变化，尤其是含氧官能团及其相关的吸附行为，并未得到充分记录。本文通过HNO ₃ -H ₂ SO ₄和NaOH-H ₂ O ₂体系的化学氧化模拟了老化的麦草生物炭。表征结果表明，碳的损失和氧的引入贯穿了整个时效过程。发现在所有处理过的生物炭中表面含氧官能团均增加，尤其是对于羧基。在老化的生物炭中观察到更多发达的中孔，用NaOH-H处理的生物炭的比表面积增加了126％₂ O ₂，对于使用40％的HNO ₃ -H ₂ SO ₄处理的生物炭来说为226％。热重分析表明，通过用碱和酸处理生物炭分别增加了含氧官能团，分别导致了14％和30％的质量损失。通过增加含氧官能团改善了生物炭表面，提高了镉的吸附能力，最大吸附能力提高了21.2％。氧化引起的粗糙表面是增加镉吸附的另一个原因。结果表明，生物炭对污染物的吸附性能会随着表面性能的变化而发生变化。