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Oxyfluorination treatment was used to enhance the capacity for adsorption of tetracycline (TC) from aqueous systems by activated carbon (AC). The AC was oxyfluorinated at room temperature for 5 min in a batch reactor, and the ratio of O2 and F2 gas was used as a variable. The oxyfluorination treatment increased the oxygen functional group content on the AC by up to 19.4%. The specific surface area of the oxyfluorinated AC was decreased by up to 31.7% and the micropore volume was decreased by up to 30.6% due to strong etching by fluorine radicals. AC-O7F3 with a 19.4 at% oxygen group content showed the best TC adsorption performance because the increased number of oxygen functional groups enabled hydrogen bonding. However, the AC-O5F5 sample treated with a high fluorine partial pressure showed poor TC adsorption, which was attributed to the collapse of the pore structure and a decrease in the specific surface area due to perfluorination. Meanwhile, the TC adsorption process showed pseudo second-order kinetics and a good fit with the Langmuir model. [ABSTRACT FROM AUTHOR]

The rates and specific capacities of lithium-ion battery anodes are important factors used in evaluating the batteries. Needle coke is attracting attention as an anode material for lithium-ion batteries due to its high reaction rates, but its low specific capacity still remains a problem to be solved. In this study, we attempted to improve the discharge capacity of needle coke-based anodes by introducing oxygen into the needle coke with ozone treatments. To confirm the effect of oxygen introduction by ozone, the structural and chemical properties of the ozonated needle coke were analyzed. The ozone treatment did not significantly affect the carbon structural properties of the needle coke but produced hydroxyl, ether, carbonyl, and carboxyl groups on the surface. The oxygen functional groups present in needle coke increased the electrochemical performance of the produced lithium-ion battery. Needle coke-based lithium-ion batteries with oxygen introduced through ozone treatment showed capacity increases of up to 17.4% and retention rates of 64.25% at 5 C. Therefore, introducing oxygen functional groups into needle cokes through ozonation is a viable strategy for producing rapid and high-capacity anode materials. [ABSTRACT FROM AUTHOR]

In this study, multi-walled carbon nanotubes (MWCNTs) were modified by thermal fluorination to improve dispersibility between MWCNTs and Li4Ti5O12 (LTO) and were used as additives to compensate for the disadvantages of LTO anode materials with low electronic conductivity. The degree of fluorination of the MWCNTs was controlled by modifying the reaction time at constant fluorination temperature; the clear structure and surface functional group changes in the MWCNTs due to the degree of fluorination were determined. In addition, the homogeneous dispersion in the LTO was improved due to the strong electronegativity of fluorine. The F-MWCNT conductive additive was shown to exhibit an excellent electrochemical performance as an anode for lithium ion batteries (LIBs). In particular, the optimized LTO with added fluorinated MWCNTs not only exhibited a high specific capacity of 104.8 mAh g−1 at 15.0 C but also maintained a capacity of ~116.8 mAh g−1 at a high rate of 10.0 C, showing a capacity almost 1.4 times higher than that of LTO with the addition of pristine MWCNTs and an improvement in the electrical conductivity. These results can be ascribed to the fact that the semi-ionic C–F bond of the fluorinated MWCNTs reacts with the Li metal during the charge/discharge process to form LiF, and the fluorinated MWCNTs are converted into MWCNTs to increase the conductivity due to the bridge effect of the conductive additive, carbon black, with LTO. [ABSTRACT FROM AUTHOR]