Xie Yanlan, Zhou Guolin, Huang Xingxue, Cao Xiupeng, Ye Anhua, Deng Yaohua, Zhang Junhong, Lin Chufa, Zhang Runhua
Institute of Vegetable Research, Wuhan Academy of Agricultural Sciences, Hubei, China; College of Horticulture and Forestry, Huazhong Agricultural University, Hubei, China.
Institute of Vegetable Research, Wuhan Academy of Agricultural Sciences, Hubei, China.
Ecotoxicol Environ Saf. 2022 Jan 15;230:113107. doi: 10.1016/j.ecoenv.2021.113107. Epub 2021 Dec 24.
It has been widely reported that biochar can be used as a cost-effective amendment to immobilize of heavy metal contaminants in soil. While less research has been conducted on effect of biochar long-term field aging on its properties and the adsorption capability. In this study, the characteristics of aged biochar were investigated by comprehensive characterization to elucidate its mechanism transformation for heavy metal immobilization. Our results showed that, compared to fresh biochar, the relative content of C of aged biochar was reduced by 34.12%, while O was increased by 8.79%. Additionally, the specific surface area, pore volume, pore size and oxygen-containing functional groups of aged biochar were significantly increased compared to the fresh biochar. Batch adsorption experiment indicated that the maximum adsorption for Cd (Q = 32.157 mg/g) and Pb (Q = 39.216 mg/g) on aged biochar surface was much larger than that of Cd (Q = 7.573 mg/g) and Pb (Q = 8.134 mg/g) on fresh biochar. The underlying adsorption mechanisms for Cd and Pb on fresh biochar were dominated by coprecipitation, cation exchange and cation-π interaction, whereas surface complexation and cation exchange appeared to be more vital for aged biochar, as more active adsorption sites and Oxygen-containing functional groups were formed on its surface during aging, which was well explained by BET, XPS, FTIR and Elemental Analysis. Our study found that the physicochemical properties of biochar changed significantly during field aging. Although these changes increased the adsorption of heavy metals by biochar, the reduced stability of biochar to passivated heavy metal ions.
已有广泛报道称，生物炭可作为一种经济高效的改良剂，用于固定土壤中的重金属污染物。然而，关于生物炭长期田间老化对其性质及吸附能力影响的研究较少。在本研究中，通过综合表征对老化生物炭的特性进行了研究，以阐明其对重金属固定的机制转变。我们的结果表明，与新鲜生物炭相比，老化生物炭的碳相对含量降低了34.12%，而氧含量增加了8.79%。此外，与新鲜生物炭相比，老化生物炭的比表面积、孔体积、孔径和含氧官能团显著增加。批量吸附实验表明，老化生物炭表面对镉（Q = 32.157 mg/g）和铅（Q = 39.216 mg/g）的最大吸附量远大于新鲜生物炭对镉（Q = 7.573 mg/g）和铅（Q = 8.134 mg/g）的吸附量。新鲜生物炭对镉和铅的潜在吸附机制主要是共沉淀、阳离子交换和阳离子-π相互作用，而表面络合和阳离子交换对老化生物炭似乎更为重要，因为老化过程中其表面形成了更多活性吸附位点和含氧官能团，这通过BET、XPS、FTIR和元素分析得到了很好的解释。我们的研究发现，生物炭在田间老化过程中其物理化学性质发生了显著变化。虽然这些变化增加了生物炭对重金属的吸附，但生物炭对钝化重金属离子的稳定性降低。
