The solid-liquid interfacial tensions of Cu(solid)-Pb(liquid)andCu(solid)-Bi(liquid)binary systems have been determined by the dihedral angle method.The results show that at 850℃ the interfacial tensions are 368±...The solid-liquid interfacial tensions of Cu(solid)-Pb(liquid)andCu(solid)-Bi(liquid)binary systems have been determined by the dihedral angle method.The results show that at 850℃ the interfacial tensions are 368±55mN/m for Cu-Pb sys-tem and 336±35mN/m for Cu-Bi systa,respectively,the error ranges of which aremore narrow than those found in some papers published abroad.In addition,there is nodetective segregation of other solute atoms or compounds in the vicinity of the tip of cop-per grain boundary where dihedral angles formed.展开更多
A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) wa...A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD) defined as 3Sbl was determined to be 8.1 μg L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD %) of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.展开更多
The study evaluates the associated environmental risk of two industrial solid waste dumpsites. The Toxicity Characteristic Leaching Procedure (TCLP) and American Society for Testing and Materials (ASTM) extraction tes...The study evaluates the associated environmental risk of two industrial solid waste dumpsites. The Toxicity Characteristic Leaching Procedure (TCLP) and American Society for Testing and Materials (ASTM) extraction test were used to characterize leachate quality on six solid waste samples obtained in July 2005, March 2006 and July 2006. Solid waste compositions varied with 58% metal scraps, 30% vegetation matter, 10% plastics and 2% paper materials. Statistical T-test (95% confidence limit) showed no significance difference in physico-chemical quality of the leachates obtained by both methods from both sites. Leachates obtained by the TCLP extraction accounted for a total of 92.4% of the overall metal load as against 6.01% for the ASTM method. This disparity is due to the acidic nature of the TCLP procedure which enhances more efficient extraction of metals than the ASTM method. Solid waste deposits at SITE-1 were considered hazardous to the environment, given that the upper 90% UCL values for lead exceeded the TCLP characteristic regulatory levels. These may pose a risk to vegetations and ground water reserve within the vicinity of the dumpsite on the long run. The risk may be such as bioaccumulation of lead in the food chain. Therefore, constant monitoring and possible remediation measures should be carried out to contained contamination.展开更多
One new three-dimensional polymeric PbⅡ complex,[Pb3(CTA)2(H2 O)2]n·nH2O(1),(H3 CTA = cis,cis-1,3,5-cyclohexanetricarboxylic acid), has been synthesized. Single-crystal X-ray diffraction analyses reveal that com...One new three-dimensional polymeric PbⅡ complex,[Pb3(CTA)2(H2 O)2]n·nH2O(1),(H3 CTA = cis,cis-1,3,5-cyclohexanetricarboxylic acid), has been synthesized. Single-crystal X-ray diffraction analyses reveal that complex 1 has a three-dimensional architecture consisting of Pb2O2 dimeric building units, which shows two types of PbⅡ centers(eight-coordinated Pb(1),six-coordinated Pb(2) and Pb(3)). The eight-coordinated Pb(1) center possesses a stereochemically ‘inactive’ electron lone pair, and the coordination sphere is holodirected. However, the arrangement of oxygen atoms around Pb(2) and Pb(3) suggests a gap or hole in the coordination geometry. The stereo-chemically ‘active’ electron lone pairs of Pb(2) and Pb(3) possibly occupy these ‘holes’ and their coordination spheres are hemidirected. Its properties have been determined by FT-IR spectra, elemental analyses and thermogravimetric analyses(TGA). Solid-state luminescent properties of 1 also have been determined, indicating strong fluorescent emissions.展开更多
The solid solution characteristics of Pb（B1/3Nb2/3）O3-based （B=Zn^2＋, Mg^2＋, Ni^2＋） composite ceramics prepared by two-phase mixed-sintering method were developed based on dielectric measurements. Results show ...The solid solution characteristics of Pb（B1/3Nb2/3）O3-based （B=Zn^2＋, Mg^2＋, Ni^2＋） composite ceramics prepared by two-phase mixed-sintering method were developed based on dielectric measurements. Results show that there are double dielectric peaks for PZN-based composite ceramic, implying two phases coexist. However single dielectric peak was presented in PMN- and PNN-based composite ceramics, respectively. It is indicated that obvious solid solution reaction exists during the sintering process of these two systems. The effects of B-site ion difference on the solid solution characteristics were discussed by crystal chemistry. SEM was employed to investigated the microstructures of composite ceramics. The influences of solid solution reaction on grain growth were discussed.展开更多
基金The project supported by the State Education Committee of China
文摘The solid-liquid interfacial tensions of Cu(solid)-Pb(liquid)andCu(solid)-Bi(liquid)binary systems have been determined by the dihedral angle method.The results show that at 850℃ the interfacial tensions are 368±55mN/m for Cu-Pb sys-tem and 336±35mN/m for Cu-Bi systa,respectively,the error ranges of which aremore narrow than those found in some papers published abroad.In addition,there is nodetective segregation of other solute atoms or compounds in the vicinity of the tip of cop-per grain boundary where dihedral angles formed.
文摘A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD) defined as 3Sbl was determined to be 8.1 μg L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD %) of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.
文摘The study evaluates the associated environmental risk of two industrial solid waste dumpsites. The Toxicity Characteristic Leaching Procedure (TCLP) and American Society for Testing and Materials (ASTM) extraction test were used to characterize leachate quality on six solid waste samples obtained in July 2005, March 2006 and July 2006. Solid waste compositions varied with 58% metal scraps, 30% vegetation matter, 10% plastics and 2% paper materials. Statistical T-test (95% confidence limit) showed no significance difference in physico-chemical quality of the leachates obtained by both methods from both sites. Leachates obtained by the TCLP extraction accounted for a total of 92.4% of the overall metal load as against 6.01% for the ASTM method. This disparity is due to the acidic nature of the TCLP procedure which enhances more efficient extraction of metals than the ASTM method. Solid waste deposits at SITE-1 were considered hazardous to the environment, given that the upper 90% UCL values for lead exceeded the TCLP characteristic regulatory levels. These may pose a risk to vegetations and ground water reserve within the vicinity of the dumpsite on the long run. The risk may be such as bioaccumulation of lead in the food chain. Therefore, constant monitoring and possible remediation measures should be carried out to contained contamination.
基金supported by the Fundamental Research Funds for the Central Universities(No.3122017071)Training Program of Innovation and Entrepreneurship for Undergraduates(No.201710059010)+1 种基金Open Project of Tianjin Key Lab Struct.&Performance Funct Mol(Tianjin Normal Univ.)National Natural Science Foundation of China(No.21501196)
文摘One new three-dimensional polymeric PbⅡ complex,[Pb3(CTA)2(H2 O)2]n·nH2O(1),(H3 CTA = cis,cis-1,3,5-cyclohexanetricarboxylic acid), has been synthesized. Single-crystal X-ray diffraction analyses reveal that complex 1 has a three-dimensional architecture consisting of Pb2O2 dimeric building units, which shows two types of PbⅡ centers(eight-coordinated Pb(1),six-coordinated Pb(2) and Pb(3)). The eight-coordinated Pb(1) center possesses a stereochemically ‘inactive’ electron lone pair, and the coordination sphere is holodirected. However, the arrangement of oxygen atoms around Pb(2) and Pb(3) suggests a gap or hole in the coordination geometry. The stereo-chemically ‘active’ electron lone pairs of Pb(2) and Pb(3) possibly occupy these ‘holes’ and their coordination spheres are hemidirected. Its properties have been determined by FT-IR spectra, elemental analyses and thermogravimetric analyses(TGA). Solid-state luminescent properties of 1 also have been determined, indicating strong fluorescent emissions.
基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(2005)
文摘The solid solution characteristics of Pb（B1/3Nb2/3）O3-based （B=Zn^2＋, Mg^2＋, Ni^2＋） composite ceramics prepared by two-phase mixed-sintering method were developed based on dielectric measurements. Results show that there are double dielectric peaks for PZN-based composite ceramic, implying two phases coexist. However single dielectric peak was presented in PMN- and PNN-based composite ceramics, respectively. It is indicated that obvious solid solution reaction exists during the sintering process of these two systems. The effects of B-site ion difference on the solid solution characteristics were discussed by crystal chemistry. SEM was employed to investigated the microstructures of composite ceramics. The influences of solid solution reaction on grain growth were discussed.
