Conductivity of glasses in the systems SiO2.PbO.RO, (where R=Ca, Sr or Ba) was investigated between room temperature and 530 K. The dependence of log resistivity as well as the activation energy on the PbO content has...Conductivity of glasses in the systems SiO2.PbO.RO, (where R=Ca, Sr or Ba) was investigated between room temperature and 530 K. The dependence of log resistivity as well as the activation energy on the PbO content has been studied. Based on the present experimental results, the possible different conduction mechanisms in such glasses are discussed. It was postulated that Pb2+ ions may represent the major charge carrying species in these glasses. This assumption was confirmed by the calculations of the mean distance between the interstitial Pb2+ ions and the effective center of the O2- ions in the glass networks. The variation in the values of the density and the molar volume with PbO content is also discussed in view of the obtained activation energies for the studied glass-systems.展开更多
In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium su...In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium sulfate could increase the maximum recovery of hemimorphite from 69.42%to 88.24%under a low concentration of Pb(Ⅱ)ions.On the hemimorphite surface pretreated with ammonium sulfate,the adsorption of Pb(Ⅱ)ions was enhanced and the main species of Pb adsorbed was changed from Pb―O/OH to PbS.This was due to the larger amount of ZnS providing more effective adsorption sites for Pb components to generate Pb S.Meanwhile,the intensity of ZnS decreased with the formation of PbS,demonstrating that ZnS was covered by PbS which formed later on the mineral surface.It was beneficial for the adsorption of butyl xanthate on the hemimorphite surface to form more hydrophobic substances.As a result,ammonium sulfate played a crucial role in realizing the efficient recovery of hemimorphite.展开更多
A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The ...A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The resulting SCP exhibited a noticeable enhanced performance for Pb（II） removal in comparison with hydroxyapatite （HAP）, being capable of easily reducing 20 ppm of Pb（II） to below the acceptable standard for drinking water within less than 10 min. Remarkably, the saturated removal capacities of Pb（II） on SCP were as high as 1720.57 mg/g calculated by the Langmuir isotherm model, exceeding largely that of the previously reported absorbents. Significantly, SCP displayed highly selective removal ability toward Pb（II） ions in the presence of the competing metal ions （Ni（II）, Co（II）, Zn（II）, and Cd（II））. Further investigations indicated that such ultra-high removal efficiency and preferable affinity of Pb（II） ions on SCP may be reasonably ascribed to the formation of rodlike hydroxypyromorphite crystals on the surface of SCP via dissolution-precipitation and ion exchange reactions, accompanied by the presence of lead sulfide precipitates. High removal efficiency, fast removal kinetics and excellent selectivity toward Pb（II） made the obtained SCP material an ideal candidate for Pb（II） ions decontamination in practical application.展开更多
Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb（Ⅱ）-imprinted polymer for selective separation and enrichment of trace Pb（Ⅱ） from aqueous solution. The prepared materia...Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb（Ⅱ）-imprinted polymer for selective separation and enrichment of trace Pb（Ⅱ） from aqueous solution. The prepared material was characterized by using the infrared spectra, X-ray diffractometer, and scanning electron microscopy. The batch experiments were conducted to study the optimal adsorption condition of adsorption trace Pb（Ⅱ） from aqueous solutions on Pb（Ⅱ）-imprinted polymer. The equilibrium was achieved in approximately 4,0 h, and the experimental kinetic data were fitted the pseudo second-order model better. The maximum adsorption capacity was 22.7 mg/g, and the Langmuir equation fitted the adsorption isotherm data. The results of selectivity experiment showed that selectively adsorbed rate of Pb（Ⅱ） on Pb（Ⅱ）-imprinted polymer was higher than all other studied ions. Desorption conditions of the adsorbed Pb（Ⅱ） from the Pb（Ⅱ）-imprinted polymer were also studied in batch experiments. The prepared Pb（Ⅱ）-imprinted polymer was shown to be promising for the separation and enrichment of trace Pb（Ⅱ） from water samples. The adsorption and desorption mechanisms were proposed.展开更多
Feldspar and Pb（NO3）2 were mixed and reacted at T=380℃ to synthesize Pb-feldspar. In the XRD （X-ray diffraction） pattern of the product, the d values （crystal lattice spacing） of the five peaks are 0.654, 0.342...Feldspar and Pb（NO3）2 were mixed and reacted at T=380℃ to synthesize Pb-feldspar. In the XRD （X-ray diffraction） pattern of the product, the d values （crystal lattice spacing） of the five peaks are 0.654, 0.342, 0.332, 0.327 and 0.257 nm. The XPS analysis results show that the binding energy of Pb 4f（7/2） in the feldspar was between 137.81-138.03 eV. Pb^2＋ can replace alkali and alkali earth cations in the feldspar structure through ion exchange reaction to form Pb-feldspar.展开更多
This paper reports sensitive high resolution ion micro-probe U-Pb zircon ages for the ＂Huoqiu Group＂ and granitoids of the Early Precambrian basement in the Huoqiu area, southeastern margin of the North China Craton...This paper reports sensitive high resolution ion micro-probe U-Pb zircon ages for the ＂Huoqiu Group＂ and granitoids of the Early Precambrian basement in the Huoqiu area, southeastern margin of the North China Craton. The ＂Huoqiu Group＂ is similar in rock association and metamorphism to the khondalite series, apart from it containing considerable amounts of banded iron formation. All detrital zircons from the ＂Huoqiu Group＂ meta-sedimentary rocks are 3.0 Ga and 2.75 Ga, without any 2.5 Ga and younger ones, as is commonly found in Paleoproterozoic khondalite series in other areas of the North China Craton. In the Huoqiu area, 2.75 Ga and 2.56 Ga granitoids have also been identified. This basement assemblage underwent strong metamorphism during the late Paleoproterozoic （-1.84 Ga） tectonothermal event that is widely developed in the North China Craton. Thus the formation time of the ＂Huoqiu Group＂ can be constrained between 2.75 and 1.84 Ga in terms of detrital and metamorphic zircon ages. It is considered, combined with regional data, that there may be a Paleoproterozoic collision orogen extending in a NWW-SEE direction to the southern margin of the North China Craton.展开更多
This paper focused on the zircon sensitive high resolution ion micro-probeU-Pb geochronology of the tourmalinites from boron-bearing series of borate deposits in Eastern Liaoning. The zircons commonly have core-rim st...This paper focused on the zircon sensitive high resolution ion micro-probeU-Pb geochronology of the tourmalinites from boron-bearing series of borate deposits in Eastern Liaoning. The zircons commonly have core-rim structures, most cores show oscillatory zoning in cathodoluminescence and plane polarized light images, suggesting a magmatic detrital origin. Ages of the magmatic detrital zircons from the hyalotonrmalite samples （N13） and （N14） are 2175 ± 5 Ma and 2171 ± 9 Ma, respectively. Moreover, metamorphic zircon from the sample （N13） shows an age of 1906 ± 4 Ma. Zircon core and rim from the hyalotourmalite sample （N02） record ages of 2171 ± 6 Ma and 1889± 62 Ma, which are explained as indicating the formation and metamorphic ages. Combined with the geological and geochemical studies, it can be concluded that the tourmalinites are formed during sedimentary exhalative mineralizations in the mid-Paleoproterozoic （-170 Ma） and underwent the metamorphism in the late-Paleoproterozoic （-1900 Ma）. The tourmalinites are the products of submarine acid volcanism in the extension rifting phase of the Liaoji Paleoproterozoic Rift, the rockforming materials of which are derived from the mantle sources with recycling crustal contamination. The emergence of tourmalinites not only indicates the mid-Paleoproterozoic tectonic-magmatic processes, but also provides impetus, heat and material sources for the mineralization of borate deposits in Eastern Liaoning.展开更多
Influence of Hg(II) and Pb(II) ions on C-Phycocyanin (C-PC) from cyanobacteria Spirulina platensis was investigated using Fluorescence spectroscopy. Fluorescence measurements demonstrate quenching of C-PC emission by ...Influence of Hg(II) and Pb(II) ions on C-Phycocyanin (C-PC) from cyanobacteria Spirulina platensis was investigated using Fluorescence spectroscopy. Fluorescence measurements demonstrate quenching of C-PC emission by Hg(II) and Pb(II), and blue shifts in the fluorescence spectra. The effect of DNA on the fluorescence of Hg(II)-and Pb(II)-C-PC (from Spirulina platensis) complexes was also studied. It was shown that the fluorescence intensity of Hg-C-PC after addition of DNA gave rise to the fluorescence buildup. At the same time, addition of DNA to the Pb(II)-C-PC complexes showed no such effect. In the case of Hg(II)-C-PC, fluorescence intensity significantly decreases in time, while for Pb(II)-C-PC, decrease of the fluorescence intensity is not significant, but blue shift of the peak takes place.展开更多
Chitosan and chitosan membranes with Pb(Ⅱ) ion as template were studied. The adsorption isotherms were correlated by dc/dt=-kcn at the temperature of 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃. By means of linear correlation,...Chitosan and chitosan membranes with Pb(Ⅱ) ion as template were studied. The adsorption isotherms were correlated by dc/dt=-kcn at the temperature of 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃. By means of linear correlation, the shapes of the isotherm curves were similar to the kinetic function of 2/C=-kt and the apparent activation energy for with chitosan(123.8 kJ·moL-1) was larger than that of membrane with Pb(Ⅱ) ion(92.3 kJ·moL-1). The chitosan membrane with Pb(Ⅱ) ion template was better "memory" function. The adsorption mechanism of chitosan with Pb(Ⅱ) was studied by IR and XPS. The results indicated that the nitrogen in-NH2 and the oxygen in C3-OH of chitosan were coordination atoms.展开更多
文摘Conductivity of glasses in the systems SiO2.PbO.RO, (where R=Ca, Sr or Ba) was investigated between room temperature and 530 K. The dependence of log resistivity as well as the activation energy on the PbO content has been studied. Based on the present experimental results, the possible different conduction mechanisms in such glasses are discussed. It was postulated that Pb2+ ions may represent the major charge carrying species in these glasses. This assumption was confirmed by the calculations of the mean distance between the interstitial Pb2+ ions and the effective center of the O2- ions in the glass networks. The variation in the values of the density and the molar volume with PbO content is also discussed in view of the obtained activation energies for the studied glass-systems.
基金the Fundamental Research Funds for the Central Universities(Nos.2022JCCXHH09 and 2022YJSHH01)the Yueqi Outstanding Scholar award of CUMTB+3 种基金the National Key R&D Program of China(No.SQ2022YFC2900065)the Ordos Science&Technology Plan(No.202204)the National Natural Science Foundation of China(No.52274283)the Open Research Fund of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF2107)。
文摘In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium sulfate could increase the maximum recovery of hemimorphite from 69.42%to 88.24%under a low concentration of Pb(Ⅱ)ions.On the hemimorphite surface pretreated with ammonium sulfate,the adsorption of Pb(Ⅱ)ions was enhanced and the main species of Pb adsorbed was changed from Pb―O/OH to PbS.This was due to the larger amount of ZnS providing more effective adsorption sites for Pb components to generate Pb S.Meanwhile,the intensity of ZnS decreased with the formation of PbS,demonstrating that ZnS was covered by PbS which formed later on the mineral surface.It was beneficial for the adsorption of butyl xanthate on the hemimorphite surface to form more hydrophobic substances.As a result,ammonium sulfate played a crucial role in realizing the efficient recovery of hemimorphite.
文摘A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The resulting SCP exhibited a noticeable enhanced performance for Pb（II） removal in comparison with hydroxyapatite （HAP）, being capable of easily reducing 20 ppm of Pb（II） to below the acceptable standard for drinking water within less than 10 min. Remarkably, the saturated removal capacities of Pb（II） on SCP were as high as 1720.57 mg/g calculated by the Langmuir isotherm model, exceeding largely that of the previously reported absorbents. Significantly, SCP displayed highly selective removal ability toward Pb（II） ions in the presence of the competing metal ions （Ni（II）, Co（II）, Zn（II）, and Cd（II））. Further investigations indicated that such ultra-high removal efficiency and preferable affinity of Pb（II） ions on SCP may be reasonably ascribed to the formation of rodlike hydroxypyromorphite crystals on the surface of SCP via dissolution-precipitation and ion exchange reactions, accompanied by the presence of lead sulfide precipitates. High removal efficiency, fast removal kinetics and excellent selectivity toward Pb（II） made the obtained SCP material an ideal candidate for Pb（II） ions decontamination in practical application.
基金supported by the National Natural Science Foundation of China (No. 20877036)
文摘Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb（Ⅱ）-imprinted polymer for selective separation and enrichment of trace Pb（Ⅱ） from aqueous solution. The prepared material was characterized by using the infrared spectra, X-ray diffractometer, and scanning electron microscopy. The batch experiments were conducted to study the optimal adsorption condition of adsorption trace Pb（Ⅱ） from aqueous solutions on Pb（Ⅱ）-imprinted polymer. The equilibrium was achieved in approximately 4,0 h, and the experimental kinetic data were fitted the pseudo second-order model better. The maximum adsorption capacity was 22.7 mg/g, and the Langmuir equation fitted the adsorption isotherm data. The results of selectivity experiment showed that selectively adsorbed rate of Pb（Ⅱ） on Pb（Ⅱ）-imprinted polymer was higher than all other studied ions. Desorption conditions of the adsorbed Pb（Ⅱ） from the Pb（Ⅱ）-imprinted polymer were also studied in batch experiments. The prepared Pb（Ⅱ）-imprinted polymer was shown to be promising for the separation and enrichment of trace Pb（Ⅱ） from water samples. The adsorption and desorption mechanisms were proposed.
文摘Feldspar and Pb（NO3）2 were mixed and reacted at T=380℃ to synthesize Pb-feldspar. In the XRD （X-ray diffraction） pattern of the product, the d values （crystal lattice spacing） of the five peaks are 0.654, 0.342, 0.332, 0.327 and 0.257 nm. The XPS analysis results show that the binding energy of Pb 4f（7/2） in the feldspar was between 137.81-138.03 eV. Pb^2＋ can replace alkali and alkali earth cations in the feldspar structure through ion exchange reaction to form Pb-feldspar.
基金supported by the Ministry of Land and Resources of the Peoples’ Republic of China (1212010711815, 1212010811033) and the Beijing SHRIMP Center
文摘This paper reports sensitive high resolution ion micro-probe U-Pb zircon ages for the ＂Huoqiu Group＂ and granitoids of the Early Precambrian basement in the Huoqiu area, southeastern margin of the North China Craton. The ＂Huoqiu Group＂ is similar in rock association and metamorphism to the khondalite series, apart from it containing considerable amounts of banded iron formation. All detrital zircons from the ＂Huoqiu Group＂ meta-sedimentary rocks are 3.0 Ga and 2.75 Ga, without any 2.5 Ga and younger ones, as is commonly found in Paleoproterozoic khondalite series in other areas of the North China Craton. In the Huoqiu area, 2.75 Ga and 2.56 Ga granitoids have also been identified. This basement assemblage underwent strong metamorphism during the late Paleoproterozoic （-1.84 Ga） tectonothermal event that is widely developed in the North China Craton. Thus the formation time of the ＂Huoqiu Group＂ can be constrained between 2.75 and 1.84 Ga in terms of detrital and metamorphic zircon ages. It is considered, combined with regional data, that there may be a Paleoproterozoic collision orogen extending in a NWW-SEE direction to the southern margin of the North China Craton.
基金supported by the National Natural Science Foundation of China grant(40073013)
文摘This paper focused on the zircon sensitive high resolution ion micro-probeU-Pb geochronology of the tourmalinites from boron-bearing series of borate deposits in Eastern Liaoning. The zircons commonly have core-rim structures, most cores show oscillatory zoning in cathodoluminescence and plane polarized light images, suggesting a magmatic detrital origin. Ages of the magmatic detrital zircons from the hyalotonrmalite samples （N13） and （N14） are 2175 ± 5 Ma and 2171 ± 9 Ma, respectively. Moreover, metamorphic zircon from the sample （N13） shows an age of 1906 ± 4 Ma. Zircon core and rim from the hyalotourmalite sample （N02） record ages of 2171 ± 6 Ma and 1889± 62 Ma, which are explained as indicating the formation and metamorphic ages. Combined with the geological and geochemical studies, it can be concluded that the tourmalinites are formed during sedimentary exhalative mineralizations in the mid-Paleoproterozoic （-170 Ma） and underwent the metamorphism in the late-Paleoproterozoic （-1900 Ma）. The tourmalinites are the products of submarine acid volcanism in the extension rifting phase of the Liaoji Paleoproterozoic Rift, the rockforming materials of which are derived from the mantle sources with recycling crustal contamination. The emergence of tourmalinites not only indicates the mid-Paleoproterozoic tectonic-magmatic processes, but also provides impetus, heat and material sources for the mineralization of borate deposits in Eastern Liaoning.
文摘Influence of Hg(II) and Pb(II) ions on C-Phycocyanin (C-PC) from cyanobacteria Spirulina platensis was investigated using Fluorescence spectroscopy. Fluorescence measurements demonstrate quenching of C-PC emission by Hg(II) and Pb(II), and blue shifts in the fluorescence spectra. The effect of DNA on the fluorescence of Hg(II)-and Pb(II)-C-PC (from Spirulina platensis) complexes was also studied. It was shown that the fluorescence intensity of Hg-C-PC after addition of DNA gave rise to the fluorescence buildup. At the same time, addition of DNA to the Pb(II)-C-PC complexes showed no such effect. In the case of Hg(II)-C-PC, fluorescence intensity significantly decreases in time, while for Pb(II)-C-PC, decrease of the fluorescence intensity is not significant, but blue shift of the peak takes place.
文摘Chitosan and chitosan membranes with Pb(Ⅱ) ion as template were studied. The adsorption isotherms were correlated by dc/dt=-kcn at the temperature of 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃. By means of linear correlation, the shapes of the isotherm curves were similar to the kinetic function of 2/C=-kt and the apparent activation energy for with chitosan(123.8 kJ·moL-1) was larger than that of membrane with Pb(Ⅱ) ion(92.3 kJ·moL-1). The chitosan membrane with Pb(Ⅱ) ion template was better "memory" function. The adsorption mechanism of chitosan with Pb(Ⅱ) was studied by IR and XPS. The results indicated that the nitrogen in-NH2 and the oxygen in C3-OH of chitosan were coordination atoms.
