Electrochemically Switched Ion Exchange Properties of PANI-SnP Composite Films in Wastewater Containing Ni2+ and Cd2+

采用滴涂法在铂基底制备了电活性聚苯胺-磷酸锡(PANI-SnP)复合膜电极，考察了该电极在Ni2+、Cd2+溶液的电控离子交换性能. 用傅立叶变换红外光谱和扫描电镜分析观察复合膜的组成及表面形貌；在0.1 mol·L-1 Ni(NO3)2、Cd(NO3)2溶液，通过循环伏安法比较了PANI膜、SnP膜及PANI-SnP复合膜电极的电化学性能，并结合电化学石英晶体微天平技术重点考察了PANI-SnP复合膜的离子交换机制；同时，通过循环伏安法调控复合膜电极的氧化还原电位，结合X射线能谱和X射线光电子能谱分别测定了其氧化和还原状态的元素组成. 结果表明，PANI-SnP复合膜电极在Ni2+、Cd2+溶液均有良好的氧化还原电活性和可逆离子交换性能，其Cd2+离子选择性优于Ni2+离子，通过电控离子交换可使Cd2+离子从镍镉废水高效分离.Electroactive PANI-SnP composite films were prepared by drop-coating method on Pt electrodes and investigated as electrochemically switched ion exchange (ESIX) materials for the separation of Cd2+ from aqueous solutions. The composition and morphology of the composite film were characterized by Fourier transform infrared spectrometer (FTIR) and scanning electron microscope (SEM). In solutions containing 0.1 mol·L-1 Ni(NO3)2 and Cd(NO3)2, cyclic voltammetry (CV) and electrochemical quartz crystal microbalance (EQCM) were used to investigate the electrochemical behavior and ion-exchange mechanism of PANI-SnP composite film. The elementary composition of PANI-SnP composite films in both oxidation and reduction states were also characterized by energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Experimental results show that the PANI-SnP composite films have reversible electrochemical behavior in aqueous solutions containing Cd2+ and Ni2+, respectively. The PANI-SnP composite film electrodes displayed a high selectivity toward Cd2+ in Cd2+/Ni2+ binary mixtures and the Cd2+ ions could be separated effectively from aqueous solutions by ESIX processes.国家自然科学基金(No. 20676089)，山西省自然科学基金(No. 2012011020-5, No. 2012011006-1)，山西省国际科技合作计划项目(No. 2011081028)资助作者联系地址：太原理工大学化学化工学院化学工程系，山西 太原 030024Author's Address: Department of Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China通讯作者E-mail：[email protected]

天山北坡三工河流域中山带森林发育与气候土壤的关系/Forest Development and Their Relationships with Climatic and Soil in the Mid-mountain Area of Sangong River Watershed, Northern Slope of Tianshan Mountains[J]

开展干旱区山地森林发育状况及其土壤因素影响的分析,对干旱区乃至全球山地森林带的成因研究具有重要的理论意义.以天山北坡三工河流域为研究区,主要利用森林调杳与遥感影像数据,确定该流域森林带的分布状况,并结合流域气象与土壤采样数据,莺点分析气候土壤因素对森林发育的影响.结果表明:1.该流域森林带位于海拔1 510～2 720 m,胸径与树高随海拔增加呈双峰曲线;其中胸径两个峰值分别位于约海拔2 000 m与2 550m,而树高峰值分别为海拔2 100 m与2 600 m,均稍高于胸径的峰值海拔高度;2.在森林带内,年均温随海拔高度增加旱线性下降趋势,最冷月均温(1月)则表现先增加后减小趋势;与其他地区相比,该流域高山林线年均温较高,最冷月均温棚筹较大,而最热月均温差异不明显;年降水量呈先增加后减小的趋势,且在海拔2 000 m左右达到最大值.土壤属性随海拔递增呈规律性的变化趋势:森林带内海拔约2 000～2 700 m树木发育较好,其有机质、全磷及令氮含量较高;CaCO3,pH值及电导率最小值与海拔2 000 m的最大降水带恰好吻合;土壤A层(0～10 cm)有机质、全磷及全氮含量与B(10～30 cm)、C(>30 cm)层差异显著,表明营养物质"表聚现象"明显,成土条件作用于土壤的深度较浅,而CaCO3,pH值与电导率各层间差异不显著.3.森林带分布格局是山降水、温度、海拔以及土壤营养等因索综合控制,方筹分析表明土壤理化性质为限制森林带内雪岭云杉生长发育的主导凶子,各生态因子对森林发育影响的作用地化为:土壤营养>降水>海拔>温度

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies