| 1 | Fractal analysis of polyferric chloride-humic acid(PFC-HA) flocs in different topological spaces显示文摘The fractal dimensions in different topological spaces of polyferric chloride-humic acid(PFC-HA) flocs,formed in flocculating different kinds of humic acids(HA) water at different initial pH(9.0,7.0,5.0) and PFC dosages,were calculated by effective densitymaximum diameter,image analysis,and N2 absorption-desorption methods,respectively. The mass fractal dimensions(Df) of PFC-HA flocs were calculated by bi-logarithm relation of effective density with maximum diameter and Logan empirical equation. The Df value was more than 2.0 at initial pH of 7.0,which was 11% and 13% higher than those at pH 9.0 and 5.0,respecively,indicating the most compact flocs formed in flocculated HA water at initial pH of 7.0. The image analysis for those flocs indicates that after flocculating the HA water at initial pH greater than 7.0 with PFC flocculant,the fractal dimensions of D2(logA vs. logdL) and D3(logVsphere vs. logdL) of PFC-HA flocs decreased with the increase of PFC dosages,and PFC-HA flocs showed a gradually looser structure. At the optimum dosage of PFC,the D2(logA vs. logdL) values of the flocs show 14%-43% difference with their corresponding Df,and they even had different tendency with the change of initial pH values. However,the D2 values of the flocs formed at three different initial pH in HA solution had a same tendency with the corresponding Df. Based on fractal Frenkel-Halsey-Hill(FHH) adsorption and desorption equations,the pore surface fractal dimensions(Ds) for dried powders of PFC-HA flocs formed in HA water with initial pH 9.0 and 7.0 were all close to 2.9421,and the Ds values of flocs formed at initial pH 5.0 were less than 2.3746. It indicated that the pore surface fractal dimensions of PFC-HA flocs dried powder mainly show the irregularity from the mesopore-size distribution and marcopore-size distribution. | WANG Yili LU Jia DU Baiyu SHI Baoyou WANG Dongsheng | 2009 | Journal of Environmental Sciences2009，21，1： | 9 |
| 2 | Revealing alkali metal ions transport mechanism in the atomic channels of Au@a-MnO_(2)显示文摘Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transport kinetics of Li^(+)/Na^(+)/K^(+)in the 2×2 channels of a-MnO_(2)with a growth direction of[001]is revealed.We show that ion radius plays a decisive role in determining the ion transport and electrochemistry.Regardless of the ion radii,Li^(+)/Na^(+)/K^(+)can all go through the 2×2 channels of a-MnO_(2),generating large stress and causing channel merging or opening.However,smaller ions such as Li^(+)and Na^(+)cannot only transport along the[001]direction but also migrate along the<110>direction to the nanowire surface;for large ion such as K^(+),diffusion along the<110>direction is prohibited.The different ion transport behavior has grand consequences in the electrochemistry of metal oxygen batteries(MOBs).For Li-O_(2)battery,Li^(+)transports uniformly to the nanowire surface,forming a uniform layer of oxide;Na^(+)also transports to the nanowire surface but may be clogged locally due to its larger radius,therefore sporadic pearl-like oxides form on the nanowire surface;K^(+)cannot transport to the nanowire surface due to its large radius,instead,it breaks the nanowire locally,causing local deposition of potassium oxides.The study provides atomic scale understanding of the alkali metal ion transport mechanism which may be harnessed to improve the performance of MOBs. | Jingzhao Chen Yong Su Hongjun Ye Yushu Tang Jitong Yan Zhiying Gao Dingding Zhu Jingming Yao Xuedong Zhang Tingting Yang Baiyu Guo Hui Li Qiushi Dai Yali Liang Jun Ma Bo Wang Haiming Sun Qiunan Liu Jing Wang Congcong Du Liqiang Zhang Yongfu Tang Jianyu Huang | 2023 | Journal of Energy Chemistry2023，，7： | 0 |
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