The flotation of kaolinite using a series of tertiary amines （N,N-dimethyl-dodecyl amine （DRN）, N,N-diethyl-dodecyl amine （DEN）, N,N-dipropyl-dodecyl amine （DPN） and N,N-dibenzyl-bodecyl amine （DBN）） was inv...The flotation of kaolinite using a series of tertiary amines （N,N-dimethyl-dodecyl amine （DRN）, N,N-diethyl-dodecyl amine （DEN）, N,N-dipropyl-dodecyl amine （DPN） and N,N-dibenzyl-bodecyl amine （DBN）） was investigated. The results show that the maximum recoveries of kaolinite for DEN, DPN and DRN are 93%, 88% and 84%, respectively, but that of DBN is very low. On the basis of zeta potential and FT-IR spectra, the ionization of surface hydroxyl and isomorphic exchange of surface ions account for the charging mechanisms of kaolinite surface. The adsorption mechanism of tertiary amines on kaolinite surface is mainly electrostatic. The isoelectric point （IEP） of kaolinite increases from 3.4 to some more positive points after the interaction of kaolinite with the four tertiary amines. The FT-IR spectra of kaolinite change with the presence of some new sharp shapes belonging to the tertiary amines. The inductive electronic effects and space-steric effects of -CH3, -C2H5, -C3H7 and -C7H7 bonding to N atom result in different collecting power of the four tertiary amines.展开更多
锂硫电池作为高能量密度的二次电池存在硫的低导电性和多硫化物的穿梭效应等问题。通过制备高还原度的氧化石墨烯隔膜,并将其应用于锂硫电池。利用石墨烯片层形成的空间位阻和小介孔结构,可阻挡多硫化物的迁移以及其高导电性可减弱电池...锂硫电池作为高能量密度的二次电池存在硫的低导电性和多硫化物的穿梭效应等问题。通过制备高还原度的氧化石墨烯隔膜,并将其应用于锂硫电池。利用石墨烯片层形成的空间位阻和小介孔结构,可阻挡多硫化物的迁移以及其高导电性可减弱电池极化。在0.2 C下,采用高还原氧化石墨烯隔膜的锂硫电池初始比容量达到了1143.2 m Ah/g,经过100次循环后容量保持率为74.25%。此外,在2 C下仍有626.1 m Ah/g的比容量。表明高还原氧化石墨烯隔膜可以有效提升锂硫电池的电化学性能,体现出卓越的长循环稳定性和杰出的倍率性能。展开更多
Sterically spacing and locating functional matters at the nanoscale exert critical effects on their application,especially for the fluorescence probes whose aggregation causes emission quenching.Here we achieved a hie...Sterically spacing and locating functional matters at the nanoscale exert critical effects on their application,especially for the fluorescence probes whose aggregation causes emission quenching.Here we achieved a hierarchical spacing strategy of DNA fluorescence probes for ion detection via locating them separately on rod-like cellulose nanocrystals(CNCs)and further isolating CNCs by pre-grafting long molecular chains.Controlling chemical structure of CNC and location degree could adjust the interspace of DNA probes(with a molecular length of ca.3.6 nm)in a range of 3.5-6.5 nm with a gradient about 0.2 nm.A length up to micrometer scale of the CNC nanorods was necessary to provide DNA probes with well-separated grafting locations and enough freedom,which brought a vast linear detection range from 10 nmol/L to 5 μmol/L of Hg^2+ concentration.The abundant reactive sites on CNC allowed a grafting pre-location of poly(tert-butyl acrylate)(PtBA)to promote the isolation of DNA probes.Controlled radical polymerization was employed to adj ust the length of PtBA molecular chains,which increased the linear sensitivity coefficient of Hg^2+ detection by ca.2.5 times.This hierarchical nanoscale spacing concept based on chemical design can hopefully cond uce to the development of biosensor and medical diagnosis.A hierarchical spacing strategy was applied to separate DNA fluorescent probes on CNCs and detect ion concentration linearly.The first-level spacing was to locate probes uniformly on CNCs,obtaining a wide linear range;and the second-level spacing was to isolate CNCs with polymer,obtaining an increased linear coefficient.展开更多
基金Project(2005CB623701) supported by the National Basic Research Program of China
文摘The flotation of kaolinite using a series of tertiary amines （N,N-dimethyl-dodecyl amine （DRN）, N,N-diethyl-dodecyl amine （DEN）, N,N-dipropyl-dodecyl amine （DPN） and N,N-dibenzyl-bodecyl amine （DBN）） was investigated. The results show that the maximum recoveries of kaolinite for DEN, DPN and DRN are 93%, 88% and 84%, respectively, but that of DBN is very low. On the basis of zeta potential and FT-IR spectra, the ionization of surface hydroxyl and isomorphic exchange of surface ions account for the charging mechanisms of kaolinite surface. The adsorption mechanism of tertiary amines on kaolinite surface is mainly electrostatic. The isoelectric point （IEP） of kaolinite increases from 3.4 to some more positive points after the interaction of kaolinite with the four tertiary amines. The FT-IR spectra of kaolinite change with the presence of some new sharp shapes belonging to the tertiary amines. The inductive electronic effects and space-steric effects of -CH3, -C2H5, -C3H7 and -C7H7 bonding to N atom result in different collecting power of the four tertiary amines.
文摘锂硫电池作为高能量密度的二次电池存在硫的低导电性和多硫化物的穿梭效应等问题。通过制备高还原度的氧化石墨烯隔膜,并将其应用于锂硫电池。利用石墨烯片层形成的空间位阻和小介孔结构,可阻挡多硫化物的迁移以及其高导电性可减弱电池极化。在0.2 C下,采用高还原氧化石墨烯隔膜的锂硫电池初始比容量达到了1143.2 m Ah/g,经过100次循环后容量保持率为74.25%。此外,在2 C下仍有626.1 m Ah/g的比容量。表明高还原氧化石墨烯隔膜可以有效提升锂硫电池的电化学性能,体现出卓越的长循环稳定性和杰出的倍率性能。
基金financially supported by the National Natural Science Foundation of China (51603171 and 51373131)Talent Project of Southwest University (SWU115034)+2 种基金Fundamental Research Funds for the Central Universities (XDJK2016C032)Key Laboratory of Polymeric Composite & Functional Materials of Ministry of Education (PCFM201605)Hubei Key Laboratory of Advanced Textile Materials & Application (Fzxcl2017003)
文摘Sterically spacing and locating functional matters at the nanoscale exert critical effects on their application,especially for the fluorescence probes whose aggregation causes emission quenching.Here we achieved a hierarchical spacing strategy of DNA fluorescence probes for ion detection via locating them separately on rod-like cellulose nanocrystals(CNCs)and further isolating CNCs by pre-grafting long molecular chains.Controlling chemical structure of CNC and location degree could adjust the interspace of DNA probes(with a molecular length of ca.3.6 nm)in a range of 3.5-6.5 nm with a gradient about 0.2 nm.A length up to micrometer scale of the CNC nanorods was necessary to provide DNA probes with well-separated grafting locations and enough freedom,which brought a vast linear detection range from 10 nmol/L to 5 μmol/L of Hg^2+ concentration.The abundant reactive sites on CNC allowed a grafting pre-location of poly(tert-butyl acrylate)(PtBA)to promote the isolation of DNA probes.Controlled radical polymerization was employed to adj ust the length of PtBA molecular chains,which increased the linear sensitivity coefficient of Hg^2+ detection by ca.2.5 times.This hierarchical nanoscale spacing concept based on chemical design can hopefully cond uce to the development of biosensor and medical diagnosis.A hierarchical spacing strategy was applied to separate DNA fluorescent probes on CNCs and detect ion concentration linearly.The first-level spacing was to locate probes uniformly on CNCs,obtaining a wide linear range;and the second-level spacing was to isolate CNCs with polymer,obtaining an increased linear coefficient.
