College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
Chemosphere. 2023 Sep;336:139187. doi: 10.1016/j.chemosphere.2023.139187. Epub 2023 Jun 17.
To decrease the environmental risks caused by heavy metals (HMs) in red mud (RM) and improve the quality of pyrolysis oil from biomass, high-temperature pretreated RM and cow dung (CD) were microwave co-pyrolyzed. Then, the optimization potential of energy consumption was evaluated and the interaction mechanism between RM and CD was explored. The results showed that the increase in transition metal oxides and specific surface area improved the microwave-absorption and catalytic capacity of the pretreated RM. By optimizing the parameters, a pretreatment temperature of 650 °C resulted in a 21.65% reduction in acid content of bio-oil, higher HMs immobilization rates (>91%) and a 7.44% reduction in energy consumption. The synergistic optimization of bio-oil quality, HMs immobilization and energy consumption was achieved. After microwave co-pyrolysis with cow dung, the larger specific surface area (92.90 m g) and higher carbon crystallinity (I/I = 1.02) of pyrolysis residues enhanced the physical adsorption to HMs. The complexation of HMs with -OH could further enhance the solidification of HMs. This work will provide support to efficient resource utilization of solid waste, and demonstrate the great potential of microwave co-pyrolysis in HMs immobilization.
为降低赤泥（RM）中重金属（HMs）造成的环境风险，提高生物质热解油的质量，采用高温预处理 RM 和牛粪（CD）进行微波共热解。然后，评估了能量消耗的优化潜力，并探讨了 RM 和 CD 之间的相互作用机制。结果表明，过渡金属氧化物和比表面积的增加提高了预处理 RM 的微波吸收和催化能力。通过优化参数，预处理温度为 650°C 时，生物油的酸含量降低了 21.65%，HMs 固定率（>91%）更高，能量消耗降低了 7.44%。实现了生物油质量、HMs 固定和能量消耗的协同优化。与牛粪进行微波共热解后，热解残渣具有更大的比表面积（92.90 m²/g）和更高的碳结晶度（I/I = 1.02），增强了对 HMs 的物理吸附。HMs 与-OH 的络合作用进一步增强了 HMs 的固化。这项工作将为固体废物的有效资源利用提供支持，并展示微波共热解在 HMs 固定方面的巨大潜力。
