College of Resources and Environment, Chengdu University of Information Technology, No. 24 Block 1, Xuefu Road, Chengdu 610225, China.
Biogas Institute of Ministry of Agriculture and Rural Affairs , Ministry of Agriculture, Chengdu 610041, China.
J Hazard Mater. 2022 Jan 5;421:126739. doi: 10.1016/j.jhazmat.2021.126739. Epub 2021 Jul 26.
The structure and composition of biochar-derived dissolved organic matter (DOM) at different pyrolysis temperatures differed significantly, affecting the environmental geochemical behavior of heavy metals (HMs). Herein, the binding properties of Cu(II) onto walnut-shell DOM were investigated using spectroscopic methods. The results showed that the DOM at low pyrolysis temperatures (300 °C and 500 °C) showed higher Cu(II) affinity than that at high pyrolysis temperature (700 °C). There was a preferential Cu(II) binding with fulvic-like substances (360 nm) at 300 °C, and with protein-like materials (275 nm) at 500 °C and 700 °C. The C-O group of alcohols, ethers, and esters showed preferential binding with Cu(II) at 300 °C and 700 °C pyrolysis temperatures. However, preferential bonding of Cu(II) to the C-O stretching vibration and O-H bending vibration of carboxyl was exhibited at 500 °C pyrolysis temperature. Pyrolysis temperature played a crucial role in the release of biochar-derived DOM and in the migration and bioavailability of HMs. Meanwhile, the adsorption effect of Cu(II) increased by 11.2% for biochar at 300 °C, and decreased by 15.0% and 61.1% for biochar at 500 °C and 700 °C, respectively, after the removal of DOM, suggesting that the presence of DOM influenced the adsorption behavior of biochar towards Cu(II).
不同热解温度下生物炭衍生溶解性有机质（DOM）的结构和组成有显著差异，影响重金属（HMs）的环境地球化学行为。在此，采用光谱方法研究了 Cu(II)在核桃壳 DOM 上的结合特性。结果表明，低热解温度（300°C 和 500°C）下的 DOM 对 Cu(II)的亲和力高于高热解温度（700°C）下的 DOM。在 300°C 时，富里酸样物质（360nm）优先与 Cu(II)结合，在 500°C 和 700°C 时，蛋白质样物质（275nm）优先与 Cu(II)结合。醇、醚和酯的 C-O 基团在 300°C 和 700°C 的热解温度下优先与 Cu(II)结合。然而，在 500°C 的热解温度下，Cu(II)优先与羧基的 C-O 伸缩振动和 O-H 弯曲振动结合。热解温度对生物炭衍生 DOM 的释放以及 HMs 的迁移和生物可利用性起着至关重要的作用。同时，在去除 DOM 后，300°C 下生物炭对 Cu(II)的吸附效果增加了 11.2%，而在 500°C 和 700°C 下生物炭对 Cu(II)的吸附效果分别降低了 15.0%和 61.1%，表明 DOM 的存在影响了生物炭对 Cu(II)的吸附行为。
