摘要
南方离子型稀土矿尾矿区的芒萁(DP)刈割废弃物存在巨大的稀土元素二次污染风险。将稀土超累积植物芒萁与4种塑料(PVC、PP、PE和PS)分别在目标温度梯度进行混合热解制得稀土生物炭,研究了芒萁及生物炭中稀土元素的含量、稀土元素形态、生物可利用性和浸出毒性,并进行稀土元素的生态风险评估。结果表明:热解能够将芒萁生物质稀土元素的不稳定态含量由60.51%降至15%以下,生物可利用性降低95%以上,从而降低固体残渣稀土元素的环境风险;添加4种塑料在600~800℃范围内热解,芒萁生物质稀土元素的不稳定态含量降至9%以内,生物可利用性降低至1%以下,浸出毒性降低80%,进一步降低了稀土元素的环境风险。因此,在一定目标温度下,将塑料与芒萁混合热解得到的稀土生物炭的异地施用不会带来新的环境风险,可实现芒萁刈割废弃物及其稀土元素的资源化、无害化利用。
The harvesting waste of Dicranopteris Pedata in the tailing areas of ionic rare earth mines in southern China poses a huge risk of secondary pollution of rare earth elements.This study aims to explore the harmless utilization of the harvesting waste of Dicranopteris Pedata and its rare earth elements through co-pyrolysis with plastics.The rare earth hyperaccumulator Dicranopteris Pedata(DP)was co-pyrolyzed with four types of plastics(PVC,PP,PE,and PS)respectively at target temperature gradients to obtain biochar containing rare earth.The contents,speciation,bioavailability,and leaching toxicity of rare earth elements in Dicranopteris Pedata and biochar were studied,and an ecological risk assessment of rare earth elements was carried out.The results showed that pyrolysis could reduce the content of unstable forms of rare earth elements in the biomass of Dicranopteris Pedata from 60.51%to 15%below,decrease the bioavailability by more than 95%,and thus reduce the environmental risk of rare earth elements in solid residues.When the four types of plastics were added and pyrolyzed within the temperature range of 600 to 800℃,the proportions of unstable forms of rare earth elements in the biomass of Dicranopteris Pedata was reduced to within 9%,the bioavailability decreased to less than 1%,and the leaching toxicity was reduced by 80%,further reducing the environmental risk of rare earth elements.Therefore,the off-site application of rare earth biochar obtained by co-pyrolyzing plastics and Dicranopteris Pedata at a certain target temperature will not bring new environmental risks.
作者
戴锦浩
熊维彬
陈志强
林强
胡文静
谢炎敏
DAI Jinhao;XIONG Weibin;CHEN Zhiqiang;LIN Qiang;HU Wenjing;XIE Yanmin(School of Geographical Sciences&Future Technology Institute for Carbon Neutrality,Fujian Normal University,Fuzhou 350108,China;Fujian Soil and Water Conservation Experimental Station,Fuzhou 350003,China;Changting County Soil and Water Conservation Bureau,Longyan 366300,China)
出处
《环境工程》
2025年第5期143-152,共10页
Environmental Engineering
基金
福建省水利科技项目“红壤侵蚀区典型生态清洁小流域水土流失治理SWAT模型构建与成效评估”
福建省水利科技项目“福建省茶果园水土保持优势地被植物筛选及其固碳效应研究”(MSK202309)。
关键词
芒萁
混合热解
稀土元素
形态分析
生态风险评价
Dicranopteris pedata
mixed pyrolysis
rare earth elements
morphological analysis
ecological risk assessment
