Polyhedron lead hydroxide carbonate （2PbCO3·Pb（OH）2 ） microcrystals have been prepared in solution phase via a facile method in the presence of surfactant cetyltrimethylammonium bromide （CTAB）. All the samp...Polyhedron lead hydroxide carbonate （2PbCO3·Pb（OH）2 ） microcrystals have been prepared in solution phase via a facile method in the presence of surfactant cetyltrimethylammonium bromide （CTAB）. All the samples were characterized by powder X-ray diffraction ,pattern （XRD）, field-emission scanning electron mi- croscopy （FE-SEM）, high-resolution transmission electron microscopy （HRTEM）, and selected area electron diffraction （SAED）. The possible growth mechanism was discussed. 2PbCO3·Pb（OH）2 microcrystals were found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol. Compared with some other catalysts, such as AlCl3, ZnCl2, and Mg5（CO3）4（OH）2, 2PbCO3·Pb（OH）2 microcrystals are stable and show relatively high activity at low catalyst amount. When the reaction was carried out at 180 12, with a molar ratio of phenol to DMC of 2：1, a reaction time 14 h, and a catalyst amount 0.2% （molar ratio to phenol）, the selectivity of DPC and methyl phenyl carbonate （MPC） was 14.7% and 78.8%, respectively.展开更多
This study developed a method to fabricate a surface-oxidized rigid carbon foam(ORCF)with hierarchical macro-nanoporous structure via KOH activation of the carbon foam with two kinds of macropores followed by HNO_(3) ...This study developed a method to fabricate a surface-oxidized rigid carbon foam(ORCF)with hierarchical macro-nanoporous structure via KOH activation of the carbon foam with two kinds of macropores followed by HNO_(3) hydrothermal oxidation.The structures of the prepared ORCF were characterized using scanning electron microscopy,transmission electron microscopy,X-ray diffraction,Fourier transform infrared(FTIR)spectra,X-ray photoelectron spectroscopy,and N_(2) adsorption-desorption analyzer.Results demonstrate that the ORCF possesses a fluffy and porous structure with rich oxygen-containing groups.There are numerous through-holes on its pore surfaces connected with two-level macropores forming hierarchical macroporous channels.Meanwhile,the ORCF remains a good bulk structure with a compression strength of 0.74 MPa at a bulk density of 0.09 g cm^(−3).Batch adsorption experiments for malachite green(MG)and Pb^(2+) were studied through the single variable method to investigate the effects of different initial conditions on its adsorption process.The ORCF has maximum adsorption capacities for MG and Pb^(2+) of 587.68 mg g^(−1) and 157.80 mg g^(−1) with high partition coefficients of 17.41 mg g^(−1)μM^(−1) and 14.86 mg g^(−1)μM^(−1),respectively.The experimental data are suitable for Langmuir isotherm and Pseudo-secondorder kinetic models,which correspond to monolayer chemisorption.Thermodynamic analysis indicates that the adsorption process is spontaneous and endothermic.Moreover,the removal percentages of MG and Pb^(2+)by the ORCF could remain above 90%after five cycles,implying that the ORCF is an efficient adsorbent with good adsorption ability and cycling stability.展开更多
基金Sponsored by the National Natural Science Foundation of China (20671011,20331010,90406002 and 90406024)"111"Project (B07012) Key Laboratory of Structural Chemistry Foundation,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences(060017)
文摘Polyhedron lead hydroxide carbonate （2PbCO3·Pb（OH）2 ） microcrystals have been prepared in solution phase via a facile method in the presence of surfactant cetyltrimethylammonium bromide （CTAB）. All the samples were characterized by powder X-ray diffraction ,pattern （XRD）, field-emission scanning electron mi- croscopy （FE-SEM）, high-resolution transmission electron microscopy （HRTEM）, and selected area electron diffraction （SAED）. The possible growth mechanism was discussed. 2PbCO3·Pb（OH）2 microcrystals were found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol. Compared with some other catalysts, such as AlCl3, ZnCl2, and Mg5（CO3）4（OH）2, 2PbCO3·Pb（OH）2 microcrystals are stable and show relatively high activity at low catalyst amount. When the reaction was carried out at 180 12, with a molar ratio of phenol to DMC of 2：1, a reaction time 14 h, and a catalyst amount 0.2% （molar ratio to phenol）, the selectivity of DPC and methyl phenyl carbonate （MPC） was 14.7% and 78.8%, respectively.
基金supported by the National Natural Science Foundation of China(Grant No.51872049)。
文摘This study developed a method to fabricate a surface-oxidized rigid carbon foam(ORCF)with hierarchical macro-nanoporous structure via KOH activation of the carbon foam with two kinds of macropores followed by HNO_(3) hydrothermal oxidation.The structures of the prepared ORCF were characterized using scanning electron microscopy,transmission electron microscopy,X-ray diffraction,Fourier transform infrared(FTIR)spectra,X-ray photoelectron spectroscopy,and N_(2) adsorption-desorption analyzer.Results demonstrate that the ORCF possesses a fluffy and porous structure with rich oxygen-containing groups.There are numerous through-holes on its pore surfaces connected with two-level macropores forming hierarchical macroporous channels.Meanwhile,the ORCF remains a good bulk structure with a compression strength of 0.74 MPa at a bulk density of 0.09 g cm^(−3).Batch adsorption experiments for malachite green(MG)and Pb^(2+) were studied through the single variable method to investigate the effects of different initial conditions on its adsorption process.The ORCF has maximum adsorption capacities for MG and Pb^(2+) of 587.68 mg g^(−1) and 157.80 mg g^(−1) with high partition coefficients of 17.41 mg g^(−1)μM^(−1) and 14.86 mg g^(−1)μM^(−1),respectively.The experimental data are suitable for Langmuir isotherm and Pseudo-secondorder kinetic models,which correspond to monolayer chemisorption.Thermodynamic analysis indicates that the adsorption process is spontaneous and endothermic.Moreover,the removal percentages of MG and Pb^(2+)by the ORCF could remain above 90%after five cycles,implying that the ORCF is an efficient adsorbent with good adsorption ability and cycling stability.
