The influences of pH, contact time, solid-liquid ratio, temperature and C60(C(COOH)2)n on Th(IV) adsorption onto the magnetic multi-walled carbon nanotubes(MMWCNTs) were studied by batch technique. The dynamic process...The influences of pH, contact time, solid-liquid ratio, temperature and C60(C(COOH)2)n on Th(IV) adsorption onto the magnetic multi-walled carbon nanotubes(MMWCNTs) were studied by batch technique. The dynamic process showed that the adsorption of Th(IV) onto MMWCNTs could reach equilibrium in 40 h and matched the pseudo-second-order kinetics model. The adsorption of Th(IV) onto MMWCNTs was significantly dependent on pH values, the adsorption ratio increased markedly at pH 3.0–5.0, and then maintained a steady state as pH values increased. At low pH, different C60(C(COOH)2)n content could enhance the adsorption content of Th(IV) onto MMWCNTs, but restrained it at higher pH. Through simulating the adsorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich models, it could be seen respectively that the adsorption pattern of Th(IV) onto MMWCNTs was mainly surface complexation, and that the adsorption process was endothermic and irreversible.展开更多
The surface properties of intrinsic and activated attapulgite were studied using potentiometric titration. The sorption mechanisms of Th（IV） on intrinsic and activated attapulgite were investigated by employing surf...The surface properties of intrinsic and activated attapulgite were studied using potentiometric titration. The sorption mechanisms of Th（IV） on intrinsic and activated attapulgite were investigated by employing surface complexation model and FITEQL 3.2 code. The results indicated that the sorption sites of intrinsic attapulgite involved in the sorption process were main ion exchange site （ ≡ XNa/K）, strong site （≡ SsOH） and weak site （ ≡ SwOH）, while only strong site （ ≡SSOH） and weak site （≡SwOH） were predominant for activated attapulgite. At pH 〈 2.5, the species of Th（IV） was main Th4＋ in aqueous solution; then the hydrolysis species of Th（IV） （i.e., Th（OH）22＋, Th（OH）3＋ and Yh（OH）40） gradually formed as pH increasing. For the sorption of Th（IV） on intrinsic attapulgite, both ion exchange species （ ≡ X2Th） and inner-sphere surface complexes （ ≡ SsOTh） were dominant, while only inner-sphere surface complexes （i.e., ≡SSOThOH and ≡ SWOTh） were observed for Th（IV） sorption to activated attapulgite. In the presence of humic acid （HA）, the sorption of Th（IV） on activated attapulgite was obviously enhanced; and both ≡ SsOH-HA-Th and≡ SSOTh were the predominant speciation. It was also interesting to find that the addition of HA obviously provoked the desorption behavior of Th（IV）.展开更多
In acidic medium, thorium(IV) can react with a bisazo dye of chromotropic acids such as arsenazo III (AA III), arsenazo M (AA M), chlorophosphonazo III (CPA III) and chlorosulphonphenol S (CSP S) to form an anionic ch...In acidic medium, thorium(IV) can react with a bisazo dye of chromotropic acids such as arsenazo III (AA III), arsenazo M (AA M), chlorophosphonazo III (CPA III) and chlorosulphonphenol S (CSP S) to form an anionic chelate which further interacts with some proteins to produce a complex. This results in a significant enhancement of intensity of the resonance Rayleigh scattering (RRS) and the appearance of a new RRS spectrum. There are a few obvious RRS peaks in the range of 400-470 nm and the most intensive peak of them is located at 470 nm. The intensity of RRS is directly proportional to the concentration of protein in the range of 0-1.6 μg·mL -1 for Th(IV)-CPA III system, 0-2.8 μg·mL -1 for Th(IV)-AA M system, 0-2.0 μg·mL -1 for Th(IV)-AA III system and 0-0.28 μg·mL -1 for Th(IV)-CSP S system, respectively. The detection limits for BSA (3σ) are 10.7 ng·mL -1 for Th(IV)-CPA III, 6.3 ng·mL -1 for Th(IV)-CSP S, 13.6 ng·mL -1 for Th(IV)-AA III and 22.1 ng·mL -1 for Th(IV)-AA M, respectively. This new RRS method has high sensitivity and fairly good selectivity and can be applied to the direct determination of proteins in human serum with satisfactory results.展开更多
A novel simple, sensitive, rapid, direct, and spectrophotometry-based procedure was investigated to determine Th(IV) at trace amounts. The new method is based on Th(IV) chelation with 3,6-dichloro-2,5-dihydroxy-l,4-be...A novel simple, sensitive, rapid, direct, and spectrophotometry-based procedure was investigated to determine Th(IV) at trace amounts. The new method is based on Th(IV) chelation with 3,6-dichloro-2,5-dihydroxy-l,4-benzoquinone(DDBQ). The reagent reacts with Th(IV) in 0.1 M HCl to form an orange 1:2 complex. The stability constant value is 6.62×10~4 for the Th(IV)complex. The Th(IV)-DDBQ obtained shows one peak with a maximum at about 346 nm. The chelate forms immediately and the absorbance remains stable for over24 h. Beer's law was obeyed in the concentration range0–10 μg mL^(-1). The molar absorptivity and Sandell's sensitivity were 4.4×10~4 L mol^(-1)cm^(-1) and 0.0053 μg cm^(-2), respectively. Different analytical parameters were tested in detail. Interfering ion(cations and anions) effects were tested. Methods for Th(IV) determination by second and third-derivative spectrophotometry were also introduced at about 344 and 341 nm, respectively. These two derivative orders offer the feature of sensitivity without the necessity for solvent extraction,heating, or pre-concentration steps. Finally, the methods were successfully utilized for Th(IV) determination in monazite, environmental water, and wastewater samples.展开更多
The BMPPT (4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione)was synthesized from BMPP. Its m.p. is 106-108℃. The results of the element analysis are as follows: C, 68.51%, H, 4.51%, N, 9.26%, S, 11.47%, wh...The BMPPT (4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione)was synthesized from BMPP. Its m.p. is 106-108℃. The results of the element analysis are as follows: C, 68.51%, H, 4.51%, N, 9.26%, S, 11.47%, which are in conformity with the theoretical value (C, 69.15%, H, 4.76%, N, 9.52%, S, 10.90%). The solvent extraction of Th4+ from nitric acid solution by BMPPT in benzene was studied. The extraction ability of BMPPT is not so high as that of its parent (BMPP). The Th4+ distribution ratio (DTh) increases with the increasing pH of the aqueous phase, and pH1/2 for Th4+ was 3.2 ([BMPPT]=0.10 mol/L). When the pH increases, the distribution ratio of Th4+ increases linearly with the slope of 1 .59. When the concentration of BMPPT increases, the distribution ratio of Th4+ increases rapidly. The lgDTh-lg[BMPPT] is linear with the slope of 1.42 and the extraction mechanism is the cation ion-exchange.展开更多
基金supported by the National Natural Science Foundation of China(J1210001)
文摘The influences of pH, contact time, solid-liquid ratio, temperature and C60(C(COOH)2)n on Th(IV) adsorption onto the magnetic multi-walled carbon nanotubes(MMWCNTs) were studied by batch technique. The dynamic process showed that the adsorption of Th(IV) onto MMWCNTs could reach equilibrium in 40 h and matched the pseudo-second-order kinetics model. The adsorption of Th(IV) onto MMWCNTs was significantly dependent on pH values, the adsorption ratio increased markedly at pH 3.0–5.0, and then maintained a steady state as pH values increased. At low pH, different C60(C(COOH)2)n content could enhance the adsorption content of Th(IV) onto MMWCNTs, but restrained it at higher pH. Through simulating the adsorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich models, it could be seen respectively that the adsorption pattern of Th(IV) onto MMWCNTs was mainly surface complexation, and that the adsorption process was endothermic and irreversible.
基金supported by the National Natural Science Foundation of China (20871062, J1030932)the Fundamental Research Funds for the Central Universities (lzujbky-2010-215)the National Synchrotron Radiation Innovation Foundation of Ministry of Education (20090137S)
文摘The surface properties of intrinsic and activated attapulgite were studied using potentiometric titration. The sorption mechanisms of Th（IV） on intrinsic and activated attapulgite were investigated by employing surface complexation model and FITEQL 3.2 code. The results indicated that the sorption sites of intrinsic attapulgite involved in the sorption process were main ion exchange site （ ≡ XNa/K）, strong site （≡ SsOH） and weak site （ ≡ SwOH）, while only strong site （ ≡SSOH） and weak site （≡SwOH） were predominant for activated attapulgite. At pH 〈 2.5, the species of Th（IV） was main Th4＋ in aqueous solution; then the hydrolysis species of Th（IV） （i.e., Th（OH）22＋, Th（OH）3＋ and Yh（OH）40） gradually formed as pH increasing. For the sorption of Th（IV） on intrinsic attapulgite, both ion exchange species （ ≡ X2Th） and inner-sphere surface complexes （ ≡ SsOTh） were dominant, while only inner-sphere surface complexes （i.e., ≡SSOThOH and ≡ SWOTh） were observed for Th（IV） sorption to activated attapulgite. In the presence of humic acid （HA）, the sorption of Th（IV） on activated attapulgite was obviously enhanced; and both ≡ SsOH-HA-Th and≡ SSOTh were the predominant speciation. It was also interesting to find that the addition of HA obviously provoked the desorption behavior of Th（IV）.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 9875 0 19)
文摘In acidic medium, thorium(IV) can react with a bisazo dye of chromotropic acids such as arsenazo III (AA III), arsenazo M (AA M), chlorophosphonazo III (CPA III) and chlorosulphonphenol S (CSP S) to form an anionic chelate which further interacts with some proteins to produce a complex. This results in a significant enhancement of intensity of the resonance Rayleigh scattering (RRS) and the appearance of a new RRS spectrum. There are a few obvious RRS peaks in the range of 400-470 nm and the most intensive peak of them is located at 470 nm. The intensity of RRS is directly proportional to the concentration of protein in the range of 0-1.6 μg·mL -1 for Th(IV)-CPA III system, 0-2.8 μg·mL -1 for Th(IV)-AA M system, 0-2.0 μg·mL -1 for Th(IV)-AA III system and 0-0.28 μg·mL -1 for Th(IV)-CSP S system, respectively. The detection limits for BSA (3σ) are 10.7 ng·mL -1 for Th(IV)-CPA III, 6.3 ng·mL -1 for Th(IV)-CSP S, 13.6 ng·mL -1 for Th(IV)-AA III and 22.1 ng·mL -1 for Th(IV)-AA M, respectively. This new RRS method has high sensitivity and fairly good selectivity and can be applied to the direct determination of proteins in human serum with satisfactory results.
文摘A novel simple, sensitive, rapid, direct, and spectrophotometry-based procedure was investigated to determine Th(IV) at trace amounts. The new method is based on Th(IV) chelation with 3,6-dichloro-2,5-dihydroxy-l,4-benzoquinone(DDBQ). The reagent reacts with Th(IV) in 0.1 M HCl to form an orange 1:2 complex. The stability constant value is 6.62×10~4 for the Th(IV)complex. The Th(IV)-DDBQ obtained shows one peak with a maximum at about 346 nm. The chelate forms immediately and the absorbance remains stable for over24 h. Beer's law was obeyed in the concentration range0–10 μg mL^(-1). The molar absorptivity and Sandell's sensitivity were 4.4×10~4 L mol^(-1)cm^(-1) and 0.0053 μg cm^(-2), respectively. Different analytical parameters were tested in detail. Interfering ion(cations and anions) effects were tested. Methods for Th(IV) determination by second and third-derivative spectrophotometry were also introduced at about 344 and 341 nm, respectively. These two derivative orders offer the feature of sensitivity without the necessity for solvent extraction,heating, or pre-concentration steps. Finally, the methods were successfully utilized for Th(IV) determination in monazite, environmental water, and wastewater samples.
文摘The BMPPT (4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione)was synthesized from BMPP. Its m.p. is 106-108℃. The results of the element analysis are as follows: C, 68.51%, H, 4.51%, N, 9.26%, S, 11.47%, which are in conformity with the theoretical value (C, 69.15%, H, 4.76%, N, 9.52%, S, 10.90%). The solvent extraction of Th4+ from nitric acid solution by BMPPT in benzene was studied. The extraction ability of BMPPT is not so high as that of its parent (BMPP). The Th4+ distribution ratio (DTh) increases with the increasing pH of the aqueous phase, and pH1/2 for Th4+ was 3.2 ([BMPPT]=0.10 mol/L). When the pH increases, the distribution ratio of Th4+ increases linearly with the slope of 1 .59. When the concentration of BMPPT increases, the distribution ratio of Th4+ increases rapidly. The lgDTh-lg[BMPPT] is linear with the slope of 1.42 and the extraction mechanism is the cation ion-exchange.
