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2018 Volume 35 Issue 12
2018, 35(12): 1399-1410
doi: 10.11944/j.issn.1000-0518.2018.12.180012
Abstract:
Catechol-containing polymers are widely used in the fields of adhesives, hydrogels, biomedicines, antifouling coatings, and self-healing materials due to good compatibility, water resistance, and adhesion.This paper describes the research progress of catechol-containing polymers.The synthesis, structure, and properties of the catechol-containing polymers, as well as its application are summarized.
Catechol-containing polymers are widely used in the fields of adhesives, hydrogels, biomedicines, antifouling coatings, and self-healing materials due to good compatibility, water resistance, and adhesion.This paper describes the research progress of catechol-containing polymers.The synthesis, structure, and properties of the catechol-containing polymers, as well as its application are summarized.
2018, 35(12): 1411-1419
doi: 10.11944/j.issn.1000-0518.2018.12.180186
Abstract:
During three dimensional optical tomography bioimaging, the imaging targets(e.g., cells or tissues) were labeled by optical probes that can emit luminescence or generate strong light scattering under the excitation of an external light source. The three dimensional bioimage including the distribution of emission light in tissue and optical parameters of tissues can be reconstructed by combination of light intensity at the tissue boundary and the model of the photon propagating in the tissue. Three-dimensional optical tomography can provide the distribution information of target in the organism, overcome the limitation of plane imaging, and have great potential in tumor detection, gene expression, protein molecular detection, and revealing the change of body function. Through analyzing the recently published research results, the review summarizes the recent progress of three-dimensional optical tomography imaging technologies including optical coherence tomography(OCT), fluorescent molecular tomography(FMT), bioluminescence tomography(BLT) and Cerenkov luminescence tomography(CLT) in the biomedical and bioanalytical fields. The technical challenges faced in practical applications are analyzed, and the corresponding solutions are discussed.
During three dimensional optical tomography bioimaging, the imaging targets(e.g., cells or tissues) were labeled by optical probes that can emit luminescence or generate strong light scattering under the excitation of an external light source. The three dimensional bioimage including the distribution of emission light in tissue and optical parameters of tissues can be reconstructed by combination of light intensity at the tissue boundary and the model of the photon propagating in the tissue. Three-dimensional optical tomography can provide the distribution information of target in the organism, overcome the limitation of plane imaging, and have great potential in tumor detection, gene expression, protein molecular detection, and revealing the change of body function. Through analyzing the recently published research results, the review summarizes the recent progress of three-dimensional optical tomography imaging technologies including optical coherence tomography(OCT), fluorescent molecular tomography(FMT), bioluminescence tomography(BLT) and Cerenkov luminescence tomography(CLT) in the biomedical and bioanalytical fields. The technical challenges faced in practical applications are analyzed, and the corresponding solutions are discussed.
2018, 35(12): 1420-1426
doi: 10.11944/j.issn.1000-0518.2018.12.180075
Abstract:
Two cylinder-forming poly(styrene-b-lactide)s, poly(styrene-b-D, L-lactide)(PS-b-PDLLA) and poly(styrene-b-L-lactide))(PS-b-PLLA), with similar domain sizes(LO) were synthesized using ring opening polymerization(ROP) of lactide monomers from hydroxy-terminated polystyrene(PS-OH) with zinc octoate(Sn(Oct)2) as the catalyst and characterized by nuclear magnetic resonance spectroscopy(NMR), gel permeation chromatography(GPC), differential scanning calorimetry(DSC), thermal gravimetric analyzer(TGA) and small-angle X-ray scattering(SAXS). Thin films of PS-b-PDLLA and PS-b-PLLA were directed to assemble on hexagonal arrays of spot chemical patterns with a range of pattern periods(LS) under thermal annealing. SEM analysis of the two assembled films revealed that long-range ordered perpendicularly-oriented hexagonal-array cylinders were obtained in both films. The range of LS window for defect-free assembly of perpendicular cylinders was larger in PS-b-PDLLA films than that in PS-b-PLLA films, which is similar to the assembly behavior of lamellar-forming PS-b-PLA on stripe chemical patterns.
Two cylinder-forming poly(styrene-b-lactide)s, poly(styrene-b-D, L-lactide)(PS-b-PDLLA) and poly(styrene-b-L-lactide))(PS-b-PLLA), with similar domain sizes(LO) were synthesized using ring opening polymerization(ROP) of lactide monomers from hydroxy-terminated polystyrene(PS-OH) with zinc octoate(Sn(Oct)2) as the catalyst and characterized by nuclear magnetic resonance spectroscopy(NMR), gel permeation chromatography(GPC), differential scanning calorimetry(DSC), thermal gravimetric analyzer(TGA) and small-angle X-ray scattering(SAXS). Thin films of PS-b-PDLLA and PS-b-PLLA were directed to assemble on hexagonal arrays of spot chemical patterns with a range of pattern periods(LS) under thermal annealing. SEM analysis of the two assembled films revealed that long-range ordered perpendicularly-oriented hexagonal-array cylinders were obtained in both films. The range of LS window for defect-free assembly of perpendicular cylinders was larger in PS-b-PDLLA films than that in PS-b-PLLA films, which is similar to the assembly behavior of lamellar-forming PS-b-PLA on stripe chemical patterns.
2018, 35(12): 1427-1433
doi: 10.11944/j.issn.1000-0518.2018.12.180038
Abstract:
Polymethyl methacrylate(PMMA) is one of important polymer materials with good transparency, but the poor flame retardancy of PMMA greatly limits its application.In this work, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO) was grafted onto the surface of silica nanoparticles that were employed to prepare PMMA nanocomposites.The results from limiting oxygen index(LOI), vertical burning(UL-94) and cone calorimeter test(CCT) indicate that the modified silica can effectively improve the flame retardancy of PMMA, which is mainly attributed to the synergistic effect between nanoparticles and phosphorous flame retardant to form compact protective carbon layer.Meanwhile, similar to pure PMMA, the as-prepared PMMA nanocomposites keep good transparency, which is positive to the wide applications of PMMA with high demand of optical transparency.
Polymethyl methacrylate(PMMA) is one of important polymer materials with good transparency, but the poor flame retardancy of PMMA greatly limits its application.In this work, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO) was grafted onto the surface of silica nanoparticles that were employed to prepare PMMA nanocomposites.The results from limiting oxygen index(LOI), vertical burning(UL-94) and cone calorimeter test(CCT) indicate that the modified silica can effectively improve the flame retardancy of PMMA, which is mainly attributed to the synergistic effect between nanoparticles and phosphorous flame retardant to form compact protective carbon layer.Meanwhile, similar to pure PMMA, the as-prepared PMMA nanocomposites keep good transparency, which is positive to the wide applications of PMMA with high demand of optical transparency.
2018, 35(12): 1434-1441
doi: 10.11944/j.issn.1000-0518.2018.12.180014
Abstract:
The fluorine modified acrylate emulsion polymerization was performed using sodium dodecyl sulfate(SDS) and octylphenyl polyoxyethylene ether(OP-10) as complex emulsifiers, 2-(perfluorohexyl) ethylmethacrylate(PFM) as the fluorinated acrylate monomer, and potassium persulfate(KPS) as the initiator.Spiropyran was physically blended with the emulsion to obtain a photochromic fluorinated acrylate emulsion.The effects of the mass ratio of methyl methacrylate(MMA) to butyl acrylate(BA) monomers, and the amount of hydroxyspiropyran(SPOH) on the polymerization and the properties of the latex films were studied by means of various spectroscopic methods.The results show that the contact angle and thermal stability of the fluorinated polyacrylate are improved.The film presents good photochromic properties with addition of 1.25%(mass fraction) spiropyran.
The fluorine modified acrylate emulsion polymerization was performed using sodium dodecyl sulfate(SDS) and octylphenyl polyoxyethylene ether(OP-10) as complex emulsifiers, 2-(perfluorohexyl) ethylmethacrylate(PFM) as the fluorinated acrylate monomer, and potassium persulfate(KPS) as the initiator.Spiropyran was physically blended with the emulsion to obtain a photochromic fluorinated acrylate emulsion.The effects of the mass ratio of methyl methacrylate(MMA) to butyl acrylate(BA) monomers, and the amount of hydroxyspiropyran(SPOH) on the polymerization and the properties of the latex films were studied by means of various spectroscopic methods.The results show that the contact angle and thermal stability of the fluorinated polyacrylate are improved.The film presents good photochromic properties with addition of 1.25%(mass fraction) spiropyran.
2018, 35(12): 1442-1448
doi: 10.11944/j.issn.1000-0518.2018.12.180102
Abstract:
In this paper, the loading of both hemoglobin and photosensitizer drug heptamethine cyanine fluorescent small molecule:11-chloro-1, 1'-di-n-propyl-3, 3, 3', 3'-tetramethyl-10, 12-trimethylene quinone three-carbon cyanine iodide salt(IR780) was achieved by the isoelectric point method. The effect of the combined treatment of hemoglobin oxygen therapy and photodynamic therapy was studied. The morphology and stability of the hemoglobin/IR780 complex drug carrier were studied by transmission electron microscopy and dynamic light scattering, proving that the drug carrier maintains good stability under physiological conditions. The reactive oxygen species(ROS) detection of the drug in the solution and cell confirmed that the oxygen supply of hemoglobin could promote the production of ROS effectively. Meanwhile, it was also confirmed that the hemoglobin/IR780 complex drug carrier was more efficient to kill tumor cells than the single component IR780 drug in cell cytotoxicity experiments.
In this paper, the loading of both hemoglobin and photosensitizer drug heptamethine cyanine fluorescent small molecule:11-chloro-1, 1'-di-n-propyl-3, 3, 3', 3'-tetramethyl-10, 12-trimethylene quinone three-carbon cyanine iodide salt(IR780) was achieved by the isoelectric point method. The effect of the combined treatment of hemoglobin oxygen therapy and photodynamic therapy was studied. The morphology and stability of the hemoglobin/IR780 complex drug carrier were studied by transmission electron microscopy and dynamic light scattering, proving that the drug carrier maintains good stability under physiological conditions. The reactive oxygen species(ROS) detection of the drug in the solution and cell confirmed that the oxygen supply of hemoglobin could promote the production of ROS effectively. Meanwhile, it was also confirmed that the hemoglobin/IR780 complex drug carrier was more efficient to kill tumor cells than the single component IR780 drug in cell cytotoxicity experiments.
2018, 35(12): 1449-1456
doi: 10.11944/j.issn.1000-0518.2018.12.180055
Abstract:
Zeolite supported Cu-based mercury-free catalysts(Cu/HY) were prepared by incipient-wetness impregnation, and their catalytic performance for acetylene hydrochlorination was evaluated in a fixed reactor.The structure parameters and theory properties of the fresh and used catalysts were characterized by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), inductively coupled plasma-atomic emission spectroscopy(ICP-AES), N2 adsorption and desorption isotherms(BET), thermogravimetry(TG), transmission electron microscopy(TEM), X-ray powder diffraction(XRD) and X-ray photoelectron spectroscopy(XPS).The acetylene conversion reached 84%, the selectivity for vinyl chloride was more than 95% and a better stability was observed on Cu/HY mercury-free catalysts with 15%(mass fraction) Cu loading, under the reaction conditions of 160℃, 101.325 kPa, a total gas hourly space of 120 h-1, V(HCl)/V(C2H2)=1.25.Besides, the characterization results show that the generation of carbon deposition, the reduction, agglomeration and loss of Cu active components are the main reasons for the decrease of the catalyst activity.
Zeolite supported Cu-based mercury-free catalysts(Cu/HY) were prepared by incipient-wetness impregnation, and their catalytic performance for acetylene hydrochlorination was evaluated in a fixed reactor.The structure parameters and theory properties of the fresh and used catalysts were characterized by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), inductively coupled plasma-atomic emission spectroscopy(ICP-AES), N2 adsorption and desorption isotherms(BET), thermogravimetry(TG), transmission electron microscopy(TEM), X-ray powder diffraction(XRD) and X-ray photoelectron spectroscopy(XPS).The acetylene conversion reached 84%, the selectivity for vinyl chloride was more than 95% and a better stability was observed on Cu/HY mercury-free catalysts with 15%(mass fraction) Cu loading, under the reaction conditions of 160℃, 101.325 kPa, a total gas hourly space of 120 h-1, V(HCl)/V(C2H2)=1.25.Besides, the characterization results show that the generation of carbon deposition, the reduction, agglomeration and loss of Cu active components are the main reasons for the decrease of the catalyst activity.
2018, 35(12): 1457-1461
doi: 10.11944/j.issn.1000-0518.2018.12.180015
Abstract:
A zinc-containing porphyrin-modified Grubbs-Hoveyda type binuclear ruthenium carbene olefin metathesis catalyst was synthesized. The structure of the product was confirmed by nuclear magnetic resonance(NMR). The yield of the ring-closing metathesis(RCM) reaction of several representative substrates could reach 95% by using 0.1% steriochemic catalyst. For a specific cross-olefin metathesis reaction(CM), a higher yield(93%) could be obtained with extended reaction time. This study provides a new method and a theoretical basis for the modification of Grubbs-Hoveyda catalyst.
A zinc-containing porphyrin-modified Grubbs-Hoveyda type binuclear ruthenium carbene olefin metathesis catalyst was synthesized. The structure of the product was confirmed by nuclear magnetic resonance(NMR). The yield of the ring-closing metathesis(RCM) reaction of several representative substrates could reach 95% by using 0.1% steriochemic catalyst. For a specific cross-olefin metathesis reaction(CM), a higher yield(93%) could be obtained with extended reaction time. This study provides a new method and a theoretical basis for the modification of Grubbs-Hoveyda catalyst.
2018, 35(12): 1462-1469
doi: 10.11944/j.issn.1000-0518.2018.12.180010
Abstract:
Low relative molecular mass gelators have attracted much attention due to their promising properties in oil spill recovery. However, designing a gelator is still challenging. In this paper, a series of organic salts was synthesized. Their structures and gelling properties were characterized by nuclear magnetic resonance spectroscopy(NMR), Fourier transform infrared spectrometer(FTIR), scanning electron microscope(SEM), vial inversion test. The results show that A3C3(A3-cinnamic acid, C3-Laurylamine) can readily gel in crude oil at room temperature. The critical gelation concentration is 6%(mass fraction). A3C3 self-assembles into dendritic three-dimensional entangled network. The formation of gel is due to the synergy between different supramolecular interactions. The increased π-π stacking interactions of the gelator made it easier to gelate. The gelators with phenyl groups are tending to gel in aromatic solvent. This gelling performance will contribute significantly toward the development of the design of organic soft materials.
Low relative molecular mass gelators have attracted much attention due to their promising properties in oil spill recovery. However, designing a gelator is still challenging. In this paper, a series of organic salts was synthesized. Their structures and gelling properties were characterized by nuclear magnetic resonance spectroscopy(NMR), Fourier transform infrared spectrometer(FTIR), scanning electron microscope(SEM), vial inversion test. The results show that A3C3(A3-cinnamic acid, C3-Laurylamine) can readily gel in crude oil at room temperature. The critical gelation concentration is 6%(mass fraction). A3C3 self-assembles into dendritic three-dimensional entangled network. The formation of gel is due to the synergy between different supramolecular interactions. The increased π-π stacking interactions of the gelator made it easier to gelate. The gelators with phenyl groups are tending to gel in aromatic solvent. This gelling performance will contribute significantly toward the development of the design of organic soft materials.
2018, 35(12): 1470-1477
doi: 10.11944/j.issn.1000-0518.2018.12.180029
Abstract:
Low-temperature oxidation is an important chemical reaction in air injection and in-situ combustion processes for enhanced oil recovery. To further understand the low temperature oxidation mechanism of intricate thermal reactions of crude oil in aerobic environment, the thermal behavior of Merey crude oil was investigated by thermogravimetry/differential thermal analysis(TG/DTA) in air and under nitrogen atmosphere. The results show that the four reaction intervals including gasification, low temperature oxidation, pyrolysis and high temperature oxidation are observed for the thermal process of Merey crude oil in air with a linear heating rate. The overlap of dominant physical and chemical processes in adjacent intervals sophisticates the characteristics of the oil thermal reaction. The invariant final temperature of gasification and low temperature oxidation intervals as well as the elevated final temperature of pyrolysis and high temperature oxidation intervals along with a raised peak temperature of pyrolysis interval are obtained as the heating rate increases. The comparison of TG/DTG experiments in air and under N2 atmosphere show that an increasing overlap of high temperature oxidation and pyrolysis intervals is observed as the heating rate increases, which is in favor of coke combustion but adverse to the enhanced oil recovery. The isothermal TG/DTA results show that the ratio of mass loss at temperature 300℃ decreases with the increase of the heating rate in air, which is not conducive to the gasification of light components of oil. The higher isothermal reaction temperature corresponds to the longer process of gasification and the greater mass loss. The oxidation is not the main reaction for Merey crude oil below 300℃.
Low-temperature oxidation is an important chemical reaction in air injection and in-situ combustion processes for enhanced oil recovery. To further understand the low temperature oxidation mechanism of intricate thermal reactions of crude oil in aerobic environment, the thermal behavior of Merey crude oil was investigated by thermogravimetry/differential thermal analysis(TG/DTA) in air and under nitrogen atmosphere. The results show that the four reaction intervals including gasification, low temperature oxidation, pyrolysis and high temperature oxidation are observed for the thermal process of Merey crude oil in air with a linear heating rate. The overlap of dominant physical and chemical processes in adjacent intervals sophisticates the characteristics of the oil thermal reaction. The invariant final temperature of gasification and low temperature oxidation intervals as well as the elevated final temperature of pyrolysis and high temperature oxidation intervals along with a raised peak temperature of pyrolysis interval are obtained as the heating rate increases. The comparison of TG/DTG experiments in air and under N2 atmosphere show that an increasing overlap of high temperature oxidation and pyrolysis intervals is observed as the heating rate increases, which is in favor of coke combustion but adverse to the enhanced oil recovery. The isothermal TG/DTA results show that the ratio of mass loss at temperature 300℃ decreases with the increase of the heating rate in air, which is not conducive to the gasification of light components of oil. The higher isothermal reaction temperature corresponds to the longer process of gasification and the greater mass loss. The oxidation is not the main reaction for Merey crude oil below 300℃.
2018, 35(12): 1478-1484
doi: 10.11944/j.issn.1000-0518.2018.12.180046
Abstract:
Fatty acid vesicles(FAVs) are a kind of important nanocontainers, but they are inherently alkaline-adapted and the pH window for the FAV formation is very narrow, which hinders their application in drug delivery. In this work, the vesicular nanocontainers were fabricated by self-assembly of conjugated linoleic acid(CLA) and sodium alginate(SA) in neutral pH range, and the membrane stability of the FAVs was enhanced. Dynamic light scattering(DLS) and transmission electron microscopy(TEM) results indicated that the vesicular nanocontainers with vesicular diameter of 50~250 nm were self-assembled in neutral pH range when the mass fraction of SA was 25%~50%. Moreover, the size of the vesicular nanocontainers increased with the increase of mass fraction of SA at pH=7.4. Based on the chemical species of SA and CLA in neutral pH range, it was proposed that hydrogen bonding is the driving force to self-assemble them into the vesicular nanocontainers. In vitro drug release results showed that the vesicular nanocontainers had a higher encapsulation efficiency and better sustained release effect. The vesicular nanocontainers are expected to be promising carriers in drug delivery.
Fatty acid vesicles(FAVs) are a kind of important nanocontainers, but they are inherently alkaline-adapted and the pH window for the FAV formation is very narrow, which hinders their application in drug delivery. In this work, the vesicular nanocontainers were fabricated by self-assembly of conjugated linoleic acid(CLA) and sodium alginate(SA) in neutral pH range, and the membrane stability of the FAVs was enhanced. Dynamic light scattering(DLS) and transmission electron microscopy(TEM) results indicated that the vesicular nanocontainers with vesicular diameter of 50~250 nm were self-assembled in neutral pH range when the mass fraction of SA was 25%~50%. Moreover, the size of the vesicular nanocontainers increased with the increase of mass fraction of SA at pH=7.4. Based on the chemical species of SA and CLA in neutral pH range, it was proposed that hydrogen bonding is the driving force to self-assemble them into the vesicular nanocontainers. In vitro drug release results showed that the vesicular nanocontainers had a higher encapsulation efficiency and better sustained release effect. The vesicular nanocontainers are expected to be promising carriers in drug delivery.
2018, 35(12): 1485-1491
doi: 10.11944/j.issn.1000-0518.2018.12.180064
Abstract:
Nanotechnology has allowed various coatings and modifications to nanostructures for applications of biomedicine. The constructions of simple, economical, controllable and biocompatible drug delivery systems(DDS) are still in demand. Here, we report a NaYF4:Yb/Tm nanoparticle-based DDS that anticancer drug doxorubicin(Dox) could be quantitatively carried by double stranded DNA thereon that self-assembled through a hybridization chain reaction(HCR). The HCR DNA was absorbed on the surface of upconversion nanoparticles(UCNPs) through linkage to photocleavable 1-(4, 5-dimethoxy-2-nitrophenyl) diazoethane(DMNPE) molecules, which can be cleaved by near ultraviolet light emitted by UCNPs under 980 nm laser light excitation. The controllable release of model drug Dox by near-infrared(NIR) should facilitate selective cytotoxicity to target region and reduced side effects and could prove promising in biomedical applications.
Nanotechnology has allowed various coatings and modifications to nanostructures for applications of biomedicine. The constructions of simple, economical, controllable and biocompatible drug delivery systems(DDS) are still in demand. Here, we report a NaYF4:Yb/Tm nanoparticle-based DDS that anticancer drug doxorubicin(Dox) could be quantitatively carried by double stranded DNA thereon that self-assembled through a hybridization chain reaction(HCR). The HCR DNA was absorbed on the surface of upconversion nanoparticles(UCNPs) through linkage to photocleavable 1-(4, 5-dimethoxy-2-nitrophenyl) diazoethane(DMNPE) molecules, which can be cleaved by near ultraviolet light emitted by UCNPs under 980 nm laser light excitation. The controllable release of model drug Dox by near-infrared(NIR) should facilitate selective cytotoxicity to target region and reduced side effects and could prove promising in biomedical applications.
2018, 35(12): 1492-1496
doi: 10.11944/j.issn.1000-0518.2018.12.180057
Abstract:
The recovery of scandium(Sc) is difficult due to its low content in resources and large amount of other metals associated with. To solve this problem, the extraction, separation and stripping of Sc by three extractants:trialkyl phosphine oxides(Cyanex 923), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester(P507) and naphthenic acid, were compared in this article. The Cyanex 923 can efficiently extract Sc from a highly acidic solution. The P507 and naphthenic acid have high extraction efficiency of Sc in low acidic solution. The best acidity for the separation between Sc and zirconium(Zr), Sc and titanium(Ti) by Cyanex 923 is 1 mol/L. The separation ratios of Sc/Zr and Sc/Ti are 5.6 and 10.6, respectively. The largest separation ratios of Sc/Zr and Sc/Ti by P507 are 21 and 59.7, respectively, at an acidity of 2 mol/L. Though the P507 has a higher separation ratio, the loaded Sc on P507 is hard to be stripped by acid. Only the Sc loaded on Cyanex 923 can be efficiently stripped when the acidity of stripping acid is 0.4 mol/L. Taking account of both separation and stripping, the Cyanex 923 is more suitable to separate and recover Sc from the leaching liquor of secondary resources.
The recovery of scandium(Sc) is difficult due to its low content in resources and large amount of other metals associated with. To solve this problem, the extraction, separation and stripping of Sc by three extractants:trialkyl phosphine oxides(Cyanex 923), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester(P507) and naphthenic acid, were compared in this article. The Cyanex 923 can efficiently extract Sc from a highly acidic solution. The P507 and naphthenic acid have high extraction efficiency of Sc in low acidic solution. The best acidity for the separation between Sc and zirconium(Zr), Sc and titanium(Ti) by Cyanex 923 is 1 mol/L. The separation ratios of Sc/Zr and Sc/Ti are 5.6 and 10.6, respectively. The largest separation ratios of Sc/Zr and Sc/Ti by P507 are 21 and 59.7, respectively, at an acidity of 2 mol/L. Though the P507 has a higher separation ratio, the loaded Sc on P507 is hard to be stripped by acid. Only the Sc loaded on Cyanex 923 can be efficiently stripped when the acidity of stripping acid is 0.4 mol/L. Taking account of both separation and stripping, the Cyanex 923 is more suitable to separate and recover Sc from the leaching liquor of secondary resources.
2018, 35(12): 1497-1506
doi: 10.11944/j.issn.1000-0518.2018.12.180016
Abstract:
Activated coke modified with cobalt(Co-AC) were prepared through impregnation and high temperature calcination method, and then characterized by BET(Brunauer-Emmett-Teller), XRD(X-ray diffraction) analysis. The adsorption of gas-phase elemental mercury by Co-AC under nitrogen and simulated syngas(N2, H2, CO, H2S) was studied on a bench-scale fixed-bed apparatus and focus on the influence of H2S. The results show that 5%Co-AC exhibits excellent Hg0 removal capacity at 120℃ and 97.8% of Hg0 can be removed in the presence of H2S. In addition, based on the density functional theory, the adsorption energy and bond length of H2S, HS and S on Co3O4 (110) surface were calculated. Firstly, H2S will dissociate into HS and S in turn by comparing the bond length of H-S. Secondly the adsorption characteristic of Hg was calculated on S-Co3O4(110). The results indicate that Hg reacts with S to form a stable HgS with an adsorption energy of -3.503 eV and the adsorption of Hg follows Eley-Rideal mechanism.With an elevated temperature, mercury removal is suppressed, because the amount of active sulfurs on the surface decreases and the interaction between Hg and S is weakened. The reaction mechanism of Hg0 removal on the surface of cobalt-based adsorbents in the presence of H2S was proved. This provides a theoretical guidance for synergistic removal of H2S and Hg0 in coal gas.
Activated coke modified with cobalt(Co-AC) were prepared through impregnation and high temperature calcination method, and then characterized by BET(Brunauer-Emmett-Teller), XRD(X-ray diffraction) analysis. The adsorption of gas-phase elemental mercury by Co-AC under nitrogen and simulated syngas(N2, H2, CO, H2S) was studied on a bench-scale fixed-bed apparatus and focus on the influence of H2S. The results show that 5%Co-AC exhibits excellent Hg0 removal capacity at 120℃ and 97.8% of Hg0 can be removed in the presence of H2S. In addition, based on the density functional theory, the adsorption energy and bond length of H2S, HS and S on Co3O4 (110) surface were calculated. Firstly, H2S will dissociate into HS and S in turn by comparing the bond length of H-S. Secondly the adsorption characteristic of Hg was calculated on S-Co3O4(110). The results indicate that Hg reacts with S to form a stable HgS with an adsorption energy of -3.503 eV and the adsorption of Hg follows Eley-Rideal mechanism.With an elevated temperature, mercury removal is suppressed, because the amount of active sulfurs on the surface decreases and the interaction between Hg and S is weakened. The reaction mechanism of Hg0 removal on the surface of cobalt-based adsorbents in the presence of H2S was proved. This provides a theoretical guidance for synergistic removal of H2S and Hg0 in coal gas.
Effect of Activated Carbon from Rice Husk on the Rate Performance of Lithium Manganese Oxide Battery
2018, 35(12): 1507-1513
doi: 10.11944/j.issn.1000-0518.2018.12.180020
Abstract:
Rice husk activated carbon(RH-AC) was synthesized via facile carbonization and activation basing on previous work. Lithium Manganese Oxide(LMO) and RH-AC were used to prepare composite electrode. Lithium metal was used as the counter electrode. Composite electrode and pure LMO electrode were tested via the galvanostatic charge/discharge(GCD). The results show that the specific capacity of 89.3 mA·h/g at 5 C rate, and the capacity retention of 89% after 100 cycles are obtained for the composite electrode with addition 5% mass fraction of RH-AC(RH-AC5). Obviously, the composite electrode exhibits higher specific capacity with better rate capability and cycle stability than those of LMO electrode. This result was further verified by the impedance simulation result and the lithium ion diffusion coefficients obtained by the cyclic voltammetric method for LMO electrode and RH-AC5 electrode.
Rice husk activated carbon(RH-AC) was synthesized via facile carbonization and activation basing on previous work. Lithium Manganese Oxide(LMO) and RH-AC were used to prepare composite electrode. Lithium metal was used as the counter electrode. Composite electrode and pure LMO electrode were tested via the galvanostatic charge/discharge(GCD). The results show that the specific capacity of 89.3 mA·h/g at 5 C rate, and the capacity retention of 89% after 100 cycles are obtained for the composite electrode with addition 5% mass fraction of RH-AC(RH-AC5). Obviously, the composite electrode exhibits higher specific capacity with better rate capability and cycle stability than those of LMO electrode. This result was further verified by the impedance simulation result and the lithium ion diffusion coefficients obtained by the cyclic voltammetric method for LMO electrode and RH-AC5 electrode.
2018, 35(12): 1514-1520
doi: 10.11944/j.issn.1000-0518.2018.12.180026
Abstract:
For expedient detection of H2S in environmental samples, a renewable H2S fluorescent probe(1-Cu2+) was constructed based on a complex formed by coumarin hydrazide oxime fluorescent ligand and a Cu2+. The probe displays very weak emission owing to quenching effect of Cu2+. The emission could be enhanced in the presence of S2-, but no obvious changes in fluorescence intensity were observed upon the addition of other relevant anionic analytes(F-, Cl-, Br-, I-, CO32-, HPO42-, H2PO4-, NO2-, NO3-, SO42-, CH3COO-, N3-, S2O32-, CN-). That is to say the probe system exhibits a remarkably selective fluorescence "ON" behavior exclusively with sulfide. The probe could be regenerated by the addition of Cu2+, and therefore the probe could be utilized repeatedly to sense sulfide anions with Cu2+ and S2-. The detection limit of the fluorescent assay for sulfide is as low as ~37.0 nmol/L with a rapid response time(a few seconds), and the linear range is 0.5~4.0 μmol/L.
For expedient detection of H2S in environmental samples, a renewable H2S fluorescent probe(1-Cu2+) was constructed based on a complex formed by coumarin hydrazide oxime fluorescent ligand and a Cu2+. The probe displays very weak emission owing to quenching effect of Cu2+. The emission could be enhanced in the presence of S2-, but no obvious changes in fluorescence intensity were observed upon the addition of other relevant anionic analytes(F-, Cl-, Br-, I-, CO32-, HPO42-, H2PO4-, NO2-, NO3-, SO42-, CH3COO-, N3-, S2O32-, CN-). That is to say the probe system exhibits a remarkably selective fluorescence "ON" behavior exclusively with sulfide. The probe could be regenerated by the addition of Cu2+, and therefore the probe could be utilized repeatedly to sense sulfide anions with Cu2+ and S2-. The detection limit of the fluorescent assay for sulfide is as low as ~37.0 nmol/L with a rapid response time(a few seconds), and the linear range is 0.5~4.0 μmol/L.
