A zeolitic imidazolate hybrid membrane(Co-IM-mIM) containing two imidazolate ligands deposited on a macroporous α-alumina support was prepared by pre-depositing and secondary growth technique. XRD, TGA and SEM charac...A zeolitic imidazolate hybrid membrane(Co-IM-mIM) containing two imidazolate ligands deposited on a macroporous α-alumina support was prepared by pre-depositing and secondary growth technique. XRD, TGA and SEM characterizations demonstrate that a stable and thin, but dense and pure-phase Co-IM-mIM membrane can be obtained on the macroporous-alumina discs in Teflon-lined autoclave at 120 °C after pre-depositing by dip-coating at room temperature. No visible cracks, pinholes or other defects were observed on the membrane layer. The gas separation studies of Co-IM-mIM membrane were carried out at 25 °C and 1×10~5 Pa, showing ideal selectivity of 6.95, 5.25, 3.40 for H_2/CO_2, H_2/N_2 and H_2/CH_4, respectively, and a permeance of 17.37× 10^(-6) mol/(m^2·s·Pa) for H_2. The influence of temperature and trans-membrane pressure on hydrogen separation and permeation was also carried out. The gas permeation and selectivity demonstrate that this membrane may have potential applications for efficient H_2 separation.展开更多
泥炭沼泽是陆地生态系统中的重要碳库之一,在全球碳循环中发挥关键作用.理解不同时空尺度下泥炭沼泽发育和碳累积及其对不同驱动因子的响应,有助于揭示泥炭沼泽生态系统的内在过程和一般规律.为探讨气候和局地条件在泥炭沼泽发育和碳累...泥炭沼泽是陆地生态系统中的重要碳库之一,在全球碳循环中发挥关键作用.理解不同时空尺度下泥炭沼泽发育和碳累积及其对不同驱动因子的响应,有助于揭示泥炭沼泽生态系统的内在过程和一般规律.为探讨气候和局地条件在泥炭沼泽发育和碳累积过程中的作用,文章利用23个泥炭基底年代研究白江河泥炭沼泽的发育和横向扩展过程;基于3个精准测年的泥炭剖面,估算碳累积速率,探究其影响因素.结果表明,白江河泥炭沼泽发育始于7.9cal. ka BP,并通过陆地沼泽化过程逐渐扩展形成. 5~4cal. ka BP的快速扩展是由于丰沛的区域降水和平坦地形.白江河泥炭沼泽3个剖面的平均碳累积速率分别为36.3、39.1和48.4g C m^(-2)a^(-1),高于北方泥炭沼泽.气候和局地条件均对白江河泥炭沼泽中全新世以来的碳累积速率具有影响. 5~1.5cal. ka BP期间碳累积速率主要受微地形、水文和植物组成等局地条件影响. 1.5cal. ka BP不同剖面碳累积速率同步下降,表明气候是该时段碳累积速率的最主要影响因素.本研究表明,在泥炭沼泽发育的不同阶段,碳累积速率的主控因子不同,局地条件在泥炭沼泽碳累积中扮演重要角色.展开更多
基金Project(21376274)supported by the National Natural Science Foundation ChinaProject(2015BAL04B02)supported by the National Key Technology R&D Program of China
文摘A zeolitic imidazolate hybrid membrane(Co-IM-mIM) containing two imidazolate ligands deposited on a macroporous α-alumina support was prepared by pre-depositing and secondary growth technique. XRD, TGA and SEM characterizations demonstrate that a stable and thin, but dense and pure-phase Co-IM-mIM membrane can be obtained on the macroporous-alumina discs in Teflon-lined autoclave at 120 °C after pre-depositing by dip-coating at room temperature. No visible cracks, pinholes or other defects were observed on the membrane layer. The gas separation studies of Co-IM-mIM membrane were carried out at 25 °C and 1×10~5 Pa, showing ideal selectivity of 6.95, 5.25, 3.40 for H_2/CO_2, H_2/N_2 and H_2/CH_4, respectively, and a permeance of 17.37× 10^(-6) mol/(m^2·s·Pa) for H_2. The influence of temperature and trans-membrane pressure on hydrogen separation and permeation was also carried out. The gas permeation and selectivity demonstrate that this membrane may have potential applications for efficient H_2 separation.
文摘泥炭沼泽是陆地生态系统中的重要碳库之一,在全球碳循环中发挥关键作用.理解不同时空尺度下泥炭沼泽发育和碳累积及其对不同驱动因子的响应,有助于揭示泥炭沼泽生态系统的内在过程和一般规律.为探讨气候和局地条件在泥炭沼泽发育和碳累积过程中的作用,文章利用23个泥炭基底年代研究白江河泥炭沼泽的发育和横向扩展过程;基于3个精准测年的泥炭剖面,估算碳累积速率,探究其影响因素.结果表明,白江河泥炭沼泽发育始于7.9cal. ka BP,并通过陆地沼泽化过程逐渐扩展形成. 5~4cal. ka BP的快速扩展是由于丰沛的区域降水和平坦地形.白江河泥炭沼泽3个剖面的平均碳累积速率分别为36.3、39.1和48.4g C m^(-2)a^(-1),高于北方泥炭沼泽.气候和局地条件均对白江河泥炭沼泽中全新世以来的碳累积速率具有影响. 5~1.5cal. ka BP期间碳累积速率主要受微地形、水文和植物组成等局地条件影响. 1.5cal. ka BP不同剖面碳累积速率同步下降,表明气候是该时段碳累积速率的最主要影响因素.本研究表明,在泥炭沼泽发育的不同阶段,碳累积速率的主控因子不同,局地条件在泥炭沼泽碳累积中扮演重要角色.
