Polyimide membranes,owing to their robust polymer backbone and facile structural tunability,are extensively used for H_(2)/CO_(2)separation.However,efficient H_(2)separation remains challenging because of the wide por...Polyimide membranes,owing to their robust polymer backbone and facile structural tunability,are extensively used for H_(2)/CO_(2)separation.However,efficient H_(2)separation remains challenging because of the wide pore size distribution within the chain-packed structure of conventional polyimides.Here,we propose a coordination crosslinking engineering strategy,where Pd2+is incorporated into an alkynyl-based polyimide containing carboxyl groups to generate coordination cross-linked networks in situ.The formed coordination bonds significantly reduce the interchain d-spacing and restrict the mobility of the polymer chains,thereby enhancing size-sieving ability.Additionally,the presence of Pd2+significantly increases the affinity of membrane for H_(2).Based on their synergistic effect,the optimized EBPA-TB-COOH@Pd2+-6 membrane(EBPA:4,4′-(ethyne-1,2-diyl)diphthalic anhydride;EBPA-TB-COOH:alkynyl-based polyimide polymer)exhibits an unprecedented combination of high H_(2)permeability(512.5 bar)and excellent H_(2)/CO_(2)selectivity(30.4),surpassing most polyimide membranes reported to date.Furthermore,the coordination crosslinking networks endow the membranes with high and stable H_(2)/CO_(2)separation performance under a wide operating pressure range(1 to 6 bar).This coordination crosslinking engineering strategy offers an effective approach for designing next-generation polyimide membranes for hydrogen recovery and purification.展开更多
Chitosan–metal complexes have been widely studied in wastewater treatment, but there are still various factors in complex preparation which are collectively responsible for improving the adsorption capacity need to b...Chitosan–metal complexes have been widely studied in wastewater treatment, but there are still various factors in complex preparation which are collectively responsible for improving the adsorption capacity need to be further studied. Thus, this study investigates the factors affecting the adsorption ability of chitosan–metal complex adsorbents, including various kinds of metal centers, different metal salts and crosslinking degree. The results show that the chitosan–Fe（ Ⅲ） complex prepared by sulfate salts exhibited the best adsorption efficiency（100%） for various dyes in very short time duration（10 min）, and its maximum adsorption capacity achieved 349.22 mg/g. The anion of the metal salt which was used in preparation played an important role to enhance the adsorption ability of chitosan–metal complex. SO4^（2-） ions not only had the effect of crosslinking through electrostatic interaction with amine group of chitosan polymer, but also could facilitate the chelation of metal ions with chitosan polymer during the synthesis process.Additionally, the p H sensitivity and the sensitivity of ionic environment for chitosan–metal complex were analyzed. We hope that these factors affecting the adsorption of the chitosan–metal complex can help not only in optimizing its use but also in designing new chitosan–metal based complexes.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.22278178)the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China(Grant No.2022D01D030)+1 种基金the National Science Foundation of Jiangsu Province,China(Grant No.BK20230106)the Fundamental Research Funds for the Central Universities,China(Grant No.JUSRP622035)。
文摘Polyimide membranes,owing to their robust polymer backbone and facile structural tunability,are extensively used for H_(2)/CO_(2)separation.However,efficient H_(2)separation remains challenging because of the wide pore size distribution within the chain-packed structure of conventional polyimides.Here,we propose a coordination crosslinking engineering strategy,where Pd2+is incorporated into an alkynyl-based polyimide containing carboxyl groups to generate coordination cross-linked networks in situ.The formed coordination bonds significantly reduce the interchain d-spacing and restrict the mobility of the polymer chains,thereby enhancing size-sieving ability.Additionally,the presence of Pd2+significantly increases the affinity of membrane for H_(2).Based on their synergistic effect,the optimized EBPA-TB-COOH@Pd2+-6 membrane(EBPA:4,4′-(ethyne-1,2-diyl)diphthalic anhydride;EBPA-TB-COOH:alkynyl-based polyimide polymer)exhibits an unprecedented combination of high H_(2)permeability(512.5 bar)and excellent H_(2)/CO_(2)selectivity(30.4),surpassing most polyimide membranes reported to date.Furthermore,the coordination crosslinking networks endow the membranes with high and stable H_(2)/CO_(2)separation performance under a wide operating pressure range(1 to 6 bar).This coordination crosslinking engineering strategy offers an effective approach for designing next-generation polyimide membranes for hydrogen recovery and purification.
基金supported by the National Natural Science Foundation of China (No. 21407021)the Shanghai Yang-Fan Program of Science and Technology Commission of Shanghai (No. 14YF1405000)+1 种基金the National Key Research and Development Program of China (No. 2016YFC0400501)the Fundamental Research Funds for the Central Universities and DHU Distinguished Young Professor Program
文摘Chitosan–metal complexes have been widely studied in wastewater treatment, but there are still various factors in complex preparation which are collectively responsible for improving the adsorption capacity need to be further studied. Thus, this study investigates the factors affecting the adsorption ability of chitosan–metal complex adsorbents, including various kinds of metal centers, different metal salts and crosslinking degree. The results show that the chitosan–Fe（ Ⅲ） complex prepared by sulfate salts exhibited the best adsorption efficiency（100%） for various dyes in very short time duration（10 min）, and its maximum adsorption capacity achieved 349.22 mg/g. The anion of the metal salt which was used in preparation played an important role to enhance the adsorption ability of chitosan–metal complex. SO4^（2-） ions not only had the effect of crosslinking through electrostatic interaction with amine group of chitosan polymer, but also could facilitate the chelation of metal ions with chitosan polymer during the synthesis process.Additionally, the p H sensitivity and the sensitivity of ionic environment for chitosan–metal complex were analyzed. We hope that these factors affecting the adsorption of the chitosan–metal complex can help not only in optimizing its use but also in designing new chitosan–metal based complexes.
