粘土矿物
吸附
稀土元素
土(古典元素)
环境化学
环境科学
地质学
地球科学
化学
矿物学
采矿工程
稀土
地球化学
物理
有机化学
数学物理
作者
Brendan Bishop,Md Samrat Alam,Shannon L. Flynn,Ning Chen,Weiduo Hao,Karthik Ramachandran Shivakumar,Logan Swaren,Daniela Gutierrez Rueda,Kurt O. Konhauser,Daniel S. Alessi,Leslie J. Robbins
标识
DOI:10.1021/acs.est.4c00974
摘要
The energy transition will have significant mineral demands and there is growing interest in recovering critical metals, including rare earth elements (REE), from secondary sources in aqueous and sedimentary environments. However, the role of clays in REE transport and deposition in these settings remains understudied. This work investigated REE adsorption to the clay minerals illite and kaolinite through pH adsorption experiments and extended X-ray absorption fine structure (EXAFS). Clay type, pH, and ionic strength (IS) affected adsorption, with decreased adsorption under acidic pH and elevated IS. Illite had a higher adsorption capacity than kaolinite; however, >95% adsorption was achieved at pH ∼7.5 regardless of IS or clay. These results were used to develop a surface complexation model with the derived binding constants used to predict REE speciation in the presence of competing sorbents. This demonstrated that clays become increasingly important as pH increases, and EXAFS modeling showed that REE can exist as both inner- and outer-sphere complexes. Together, this indicated that clays can be an important control on the transport and enrichment of REE in sedimentary systems. These findings can be applied to identify settings to target for resource extraction or to predict REE transport and fate as a contaminant.
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