Gang Chu,Jing Zhao,Yu Zhang,Kai Sun,Xiaohong Liu,Youbin Si,Bo Pan,Christian E. W. Steinberg
Biochar is a multiphase carbonaceous structure with inherent minerals. The role of minerals in organic sorption is essential for biochar application in environmental remediation. In this work, combined with X-ray diffraction (XRD) and 13C nuclear magnetic resonance (NMR) techniques, the composition of minerals and the sorption behavior of bisphenol A (BPA) were investigated. A demineralization treatment was applied to remove surface minerals containing silicon (Si), aluminum (Al), and calcium (Ca) elements, resulting in the exposure of micropores in aromatic carbon. These minerals could serve as vital sites to facilitate BPA sorption due to the complexation mechanism. The role of mineral elements in enhanced sorption could be in the sequence of Al mineral > Ca mineral > no mineral. Density functional theory (DFT) calculation confirmed the occurrence of complexation between minerals and BPA as evidenced by sorption energy. After demineralization, declined release ratio (RR) values implied that adsorbed BPA on demineralized biochars was more difficult to desorb than on original biochars owing to the restriction of micropores. The enhanced energy gap also verified that BPA molecules were more stable on demineralized biochars. This research casts new light on recognizing biochar minerals in relation to their underlying sorption mechanism for phenolic compounds.
Tianyu Zheng,Lianjing Mao,Xiao Li,Chunsen Ye,Pengrui Zhang,Wei Sun,Jinhe Sun
With the rapid development of the lithium-ion battery industry, the demand for lithium resources is becoming more and more urgent. Lithium extraction is a widely used process; especially, tributyl phosphate (TBP) systems have attracted much attention. During the extraction and purification process of lithium ions, the extractant TBP may encounter issues including aging, emulsification, precipitation, and low utilization rates. These problems arise due to an inadequate understanding of the extraction mechanism. In this work, the TBP-ionic liquid system was utilized to extract Li+, the variations of trace water in the organic phase were systematically and quantitatively investigated, and the extraction mechanism was further investigated. Experiments have confirmed that TBP forms a 1:1 complex with water. Various complex ratios of TBP, Li+, and water were determined, and the structures were verified by simulations. The complexes have three different ratios of TBP, Li+, and water: 2:1:2, 3:1:1, and 4:1:0. Water molecules are substituted during the complexation of Li+ with TBP, and meanwhile, the NTf2– anion equilibrates the charge of the Li+-TBP complex. This work provides experimental data and a theoretical basis for understanding Li+ extraction in the TBP-ionic liquid system, which is conducive to the sustainable development of the lithium industry.
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