College of Environment, Shenyang University, Shenyang, 110044, China.
College of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang, 110168, China.
Environ Sci Pollut Res Int. 2024 Mar;31(13):19409-19422. doi: 10.1007/s11356-024-32406-x. Epub 2024 Feb 15.
The aging process can affect the physical and chemical properties as well as adsorption capacity of biochar. This study focuses on the heavy metal cadmium (Cd) as the research object, and artificially ages biochar prepared from rice straw and corn straw through accelerated freeze-thaw cycles, alternating dry wet cycles, and ultraviolet light treatment, in order to evaluate the effects of different aging conditions on the physical and chemical properties of the two different types of biochar and on their adsorption capacities for Cd. After aging, the pH of rice and corn biochar decreased to varying degrees, respectively. The surface structure was ruptured, the average pore diameter was decreased, and the specific surface area was increased by 27.3%, 21.9%, and 9.8% (rice) and 95.4%, 27.7%, and 13.4% (corn). Ultraviolet light aging has the most significant impact on the elemental content of biochar, and the C content was decreased by 12.4% (rice) and 9.3% (corn). The O content was increased by 11.2% (rice) and 44.1% (corn), and the numbers of O/C, H/C, (O + N)/C, and oxygen-containing functional groups were increased. These results demonstrate that the aging process reduces the degree of aromatization of biochar, while enhancing its polarity and Cd adsorption capacity. Rice straw biochar (RSB) has a greater ability to adsorb Cd than corn straw biochar (CSB). In addition, ultraviolet light aging is particularly effective in increasing heavy metal adsorption.
衰老过程会影响生物炭的物理化学性质和吸附能力。本研究以重金属镉（Cd）为研究对象，通过加速冻融循环、干湿交替循环和紫外线处理对水稻秸秆和玉米秸秆制备的生物炭进行人工老化，以评估不同老化条件对两种不同类型生物炭的物理化学性质及其对 Cd 的吸附能力的影响。老化后，稻、玉米生物炭的 pH 值分别不同程度降低。表面结构破裂，平均孔径减小，比表面积分别增加了 27.3%、21.9%和 9.8%（稻）和 95.4%、27.7%和 13.4%（玉米）。紫外线老化对生物炭的元素含量影响最大，C 含量分别减少了 12.4%（稻）和 9.3%（玉米）。O 含量分别增加了 11.2%（稻）和 44.1%（玉米），O/C、H/C、（O+N）/C 和含氧官能团的数量增加。这些结果表明，老化过程降低了生物炭的芳构化程度，同时增强了其极性和 Cd 吸附能力。水稻秸秆生物炭（RSB）比玉米秸秆生物炭（CSB）具有更强的吸附 Cd 的能力。此外，紫外线老化特别有效地增加了重金属的吸附。
