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
A natural polymer catalyst, silica-supported chitosan palladium complex (abbr. as SiO2-CS-Pd) was found to catalyze the hydrogenation of phenol and cresols to corresponding cyclohexanones in high yield and 100% select...A natural polymer catalyst, silica-supported chitosan palladium complex (abbr. as SiO2-CS-Pd) was found to catalyze the hydrogenation of phenol and cresols to corresponding cyclohexanones in high yield and 100% selectivity at 70 degrees C and 1.01325 x 10(5) Pa mild conditions. N/Pd molar ratio in the complex, temperature and solvents have much influence on the reaction. The reactivity order of reactants was found to be: phenol >m->p->o- The catalyst is stable during the reaction and could be repeatedly used for several times without much decrease in its catalytic activity.展开更多
The hybrid material based on polyelectrolyte complexes of chitosan with oxycompounds of cobalt and nickel was electrodeposited on a stainless steel plate using the method of non-stationary electrolysis.The hybrid mate...The hybrid material based on polyelectrolyte complexes of chitosan with oxycompounds of cobalt and nickel was electrodeposited on a stainless steel plate using the method of non-stationary electrolysis.The hybrid material layer was investigated by scanning electron microscopy,atomic force microscopy,transmission elec-tron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,Brunauer-Emmett-Teller method,Fourier transform infrared spectroscopy,and Raman spectroscopy.The electrocatalytic properties of the hybrid material were studied in the hydrogen evolution reaction in alkaline electrolyte(1 mol·L−1 NaOH).It was determined that during the initial four-hour period of the hydrogen evolution process,the overpotential underwent a substan-tial decline,remaining constant for a minimum of 17 h thereafter,from 289 up to 210 mV at−10 mA·cm^(−2).After a long-term hydrogen evolution,the activity of the hybrid material electrode exceeded hydrogen evolution reaction activity by 20%Pt/C commercial catalyst at a high current density of−100 mA·cm−2.展开更多
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.
文摘A natural polymer catalyst, silica-supported chitosan palladium complex (abbr. as SiO2-CS-Pd) was found to catalyze the hydrogenation of phenol and cresols to corresponding cyclohexanones in high yield and 100% selectivity at 70 degrees C and 1.01325 x 10(5) Pa mild conditions. N/Pd molar ratio in the complex, temperature and solvents have much influence on the reaction. The reactivity order of reactants was found to be: phenol >m->p->o- The catalyst is stable during the reaction and could be repeatedly used for several times without much decrease in its catalytic activity.
基金supported by the Ministry of Science and Higher Education of the Russian Federation within the governmental assignment for Boreskov Institute of Catalysis(Project No.FWUR-2024-0036)(A.N.Kuznetsov)supported by the Ministry of Science and Higher Education of the Russian Federation(Project No.121031700314-5)(K.M.Popov).
文摘The hybrid material based on polyelectrolyte complexes of chitosan with oxycompounds of cobalt and nickel was electrodeposited on a stainless steel plate using the method of non-stationary electrolysis.The hybrid material layer was investigated by scanning electron microscopy,atomic force microscopy,transmission elec-tron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,Brunauer-Emmett-Teller method,Fourier transform infrared spectroscopy,and Raman spectroscopy.The electrocatalytic properties of the hybrid material were studied in the hydrogen evolution reaction in alkaline electrolyte(1 mol·L−1 NaOH).It was determined that during the initial four-hour period of the hydrogen evolution process,the overpotential underwent a substan-tial decline,remaining constant for a minimum of 17 h thereafter,from 289 up to 210 mV at−10 mA·cm^(−2).After a long-term hydrogen evolution,the activity of the hybrid material electrode exceeded hydrogen evolution reaction activity by 20%Pt/C commercial catalyst at a high current density of−100 mA·cm−2.
