A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of titanium(IV),based upon the catalytic effect of Ti(IV) on the oxidation of acid chrome blue K (ACBK) by hydrogen perox...A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of titanium(IV),based upon the catalytic effect of Ti(IV) on the oxidation of acid chrome blue K (ACBK) by hydrogen peroxide in 0.002 mol/L sulfuric acid,is described. The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of ACBK at 524 nm. The detection limit of the method is 1.01×10?9 g/mL,and the linear range is 0-0.048 mg/L. The influence of acidity,concentration of reactants,reaction time,reaction temperature and for-eign ions is also discussed. The optimum reaction conditions were established and some kinetic parameters determined. The apparent activation energy of the catalytic reaction is 5.32 kJ/mol. The relative standard deviation for the determi-nation of titanium(IV) at the concentration of 0.048 mg/L is calculated to be 1.31% (n = 11). In combination with sol-vent extraction separation,the method has been successfully applied to the determination of trace titanium(IV) in human hair,plant matter,tea and rock samples. The results are in good agreement with the certified values with the relative standard deviations (RSD) of 1.4%-3.5%.展开更多
[Cyclopentadien-Fe-naphthalene]BF4(CFN) and [cyclopentadien-Fe-anisole]BF4(CFA) as thermal cationic initiators for the curing of epoxide E44 and GGE were investigated. CFN brought out the curing of E44 at 89.1℃ and t...[Cyclopentadien-Fe-naphthalene]BF4(CFN) and [cyclopentadien-Fe-anisole]BF4(CFA) as thermal cationic initiators for the curing of epoxide E44 and GGE were investigated. CFN brought out the curing of E44 at 89.1℃ and that of GGE at 148.7℃. However, CFA had much less thermal initiating activity under 300℃. Under UV radiation for short time, the thermal initiating activities of CFN and CFA were enhanced obviously. It was observed that the initiating onset temperature decreased and the evolved heat of the curing increased. Both CFN and CFA can carry out the polymerization of E44 and GGE near 85℃ and 112℃ by UV radiation.展开更多
The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formatio...The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formation was determined by analyzing the experimental data——either based on the shading ratio data of laser detector or based on the pressure drop data of the flow system. The induction period of CC12F2 (R12) in pure water and that of CH4 in (tetrahydrofuran ＋ water) systems were then measured with the above two methods. Experimental data show that the induction period depends on the driving force exponentially. Flow rate also has a significant influence on the hydrate nucleation. A new induction period model taking the driving force and liquid flow rate into account was proposed. And it is successfully applied to the calculation of the induction period, which is in good agreement with the experimental data obtained in this study.展开更多
To address the environmental and health hazards of nitrate(NO_(3)^(-))in water,a denitrification advanced reduction process(ARP)using only formic acid(HCOOH)activated by ultraviolet(UV)light was proposed.The efficienc...To address the environmental and health hazards of nitrate(NO_(3)^(-))in water,a denitrification advanced reduction process(ARP)using only formic acid(HCOOH)activated by ultraviolet(UV)light was proposed.The efficiency,influencing factors,mechanism,and kinetics of the reduction were investigated through component analysis and radical detection.Results show that,after 90 min of UV illumination,the reduction and gas conversion ratios of 50 mg/L NO_(3)^(-)-N reach 99.9%and 99.8%,respectively,under 9 mM of C_(0)(HCOOH),pH=3.0,and N_(2) aeration.Meanwhile,96.7%of HCOOH is consumed and converted into gas.The NO_(3)^(-)-N conversion process includes the transformation to NO_(2)^(-)-N,followed by a further reduction to gas and a direct conversion into gas,introducing small amounts of nitrite and ammonia.The carbon dioxide anion radical(·CO_(2)^(-))from HCOOH/HCOO^(-)is the principal cause of NO_(3)^(-)-N reduction by UV/HCOOH/N 2 ARP.In contrast,·CO_(2)^(-)production is caused by the hydroxyl radical(·OH).The NO_(3)^(-)-N reduction efficiency is enhanced by the increase in the light intensity,considerably affected by the initial pH,and less affected by inorganic anions,including Cl^(-),H_(2)PO_(4)^(-),and HCO_(3)^(-)/CO_(3)^(2-).The initial HCOOH concentration and light intensity are the main factors that influence the NO_(3)^(-)-N reduction rate.展开更多
Deleterious chlorine fluorescence was found to occur at the same frequency as the Raman scattering of 02 （1 A） and 02 （3 E）, seriously affecting the 02 （1 A） yield measurement in the reaction of chlorine with ba...Deleterious chlorine fluorescence was found to occur at the same frequency as the Raman scattering of 02 （1 A） and 02 （3 E）, seriously affecting the 02 （1 A） yield measurement in the reaction of chlorine with basic hydrogen peroxide by use of the Raman spectroscopy technique. To solve this problem we have taken advantage of the fact that Raman radiation is always strongly polarized while fluorescence is essentially non-polarized in a gaseous medium. When chlorine utilization of a singlet oxygen generator is 88%, 02（1A） yield reaches （42.4±7.4）% with the effect of chlorine fluorescence completely eliminated.展开更多
As a bio-recalcitrant organic pollutant in paper mill effluent, lignin is generally removed by an advanced oxidation process, such as a TiO2/H2O2 photocatalytic technique under irradiation with ultraviolet light, whic...As a bio-recalcitrant organic pollutant in paper mill effluent, lignin is generally removed by an advanced oxidation process, such as a TiO2/H2O2 photocatalytic technique under irradiation with ultraviolet light, which only accounts for less than 5% of sunlight. Herein, we reported a TiO2/H2O2-based thermally-assisted photocatalytic process that allows lignin to be efficiently degraded under visible/near-infrared light at an elevated temperature. Adsorption of H2O2 on TiO2 nanoparticles and an increase of temperature facilitate the production and separation of charge carriers under near-infrared and visible light irradiation, accelerate carrier transfer at the TiO2-electrolyte interface and promote the production of hydroxyl radicals, A higher level of H2O2 addition results in an increased degradation rate of lignin,while the optimal temperature for the thermally-assisted photodegradation of lignin is 70℃. A charge carrier excitation and transfer process was proposed for the TiO2/H2O2, thermally-assisted photocatalytic process. This work describes a new method for the photodegradation of organic pollutants,such as residual lignin in paper mill effluent, using wide band gap semiconductors under visible and near-infrared light irradiation.展开更多
A differential carbon monoxide(CO) concentration sensing device using a self-fabricated spherical mirror(e.g.light-collector) and a multi-pass gas-chamber is presented in this paper.Single-source dual-channel detectio...A differential carbon monoxide(CO) concentration sensing device using a self-fabricated spherical mirror(e.g.light-collector) and a multi-pass gas-chamber is presented in this paper.Single-source dual-channel detection method is adopted to suppress the interferences from light source,optical path and environmental changes.Detection principle of the device is described,and both the optical part and the electrical part are developed.Experiments are carried out to evaluate the sensing performance on CO concentration.The results indicate that at 1.013×10~5 Pa and 298 K,the limit of detection(LoD) is about 11.5 mg/m^3 with an absorption length of 40 cm.As the gas concentration gets larger than115 mg/m^3(1.013×10~5 Pa,298 K),the relative detection error falls into the range of-1.7%—+1.9%.Based on 12 h long-term measurement on the 115 mg/m^3 and 1 150 mg/m^3 CO samples,the maximum detection errors are about0.9%and 5.5%,respectively.Due to the low cost and competitive characteristics,the proposed device shows potential applications in CO detection in the circumstances of coal-mine production and environmental protection.展开更多
基金Project 0520002 supported by the Natural Science Foundation of Jiangxi Province
文摘A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of titanium(IV),based upon the catalytic effect of Ti(IV) on the oxidation of acid chrome blue K (ACBK) by hydrogen peroxide in 0.002 mol/L sulfuric acid,is described. The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of ACBK at 524 nm. The detection limit of the method is 1.01×10?9 g/mL,and the linear range is 0-0.048 mg/L. The influence of acidity,concentration of reactants,reaction time,reaction temperature and for-eign ions is also discussed. The optimum reaction conditions were established and some kinetic parameters determined. The apparent activation energy of the catalytic reaction is 5.32 kJ/mol. The relative standard deviation for the determi-nation of titanium(IV) at the concentration of 0.048 mg/L is calculated to be 1.31% (n = 11). In combination with sol-vent extraction separation,the method has been successfully applied to the determination of trace titanium(IV) in human hair,plant matter,tea and rock samples. The results are in good agreement with the certified values with the relative standard deviations (RSD) of 1.4%-3.5%.
文摘[Cyclopentadien-Fe-naphthalene]BF4(CFN) and [cyclopentadien-Fe-anisole]BF4(CFA) as thermal cationic initiators for the curing of epoxide E44 and GGE were investigated. CFN brought out the curing of E44 at 89.1℃ and that of GGE at 148.7℃. However, CFA had much less thermal initiating activity under 300℃. Under UV radiation for short time, the thermal initiating activities of CFN and CFA were enhanced obviously. It was observed that the initiating onset temperature decreased and the evolved heat of the curing increased. Both CFN and CFA can carry out the polymerization of E44 and GGE near 85℃ and 112℃ by UV radiation.
基金the National 973 Program of China (No. 2001CB209107) the National 863 Project of China (No. 2002AA615120) Huo Yingdong Education Foundation.
文摘The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formation was determined by analyzing the experimental data——either based on the shading ratio data of laser detector or based on the pressure drop data of the flow system. The induction period of CC12F2 (R12) in pure water and that of CH4 in (tetrahydrofuran ＋ water) systems were then measured with the above two methods. Experimental data show that the induction period depends on the driving force exponentially. Flow rate also has a significant influence on the hydrate nucleation. A new induction period model taking the driving force and liquid flow rate into account was proposed. And it is successfully applied to the calculation of the induction period, which is in good agreement with the experimental data obtained in this study.
基金The National Major Science and Technology Project(No.2017ZX07202-004-005)。
文摘To address the environmental and health hazards of nitrate(NO_(3)^(-))in water,a denitrification advanced reduction process(ARP)using only formic acid(HCOOH)activated by ultraviolet(UV)light was proposed.The efficiency,influencing factors,mechanism,and kinetics of the reduction were investigated through component analysis and radical detection.Results show that,after 90 min of UV illumination,the reduction and gas conversion ratios of 50 mg/L NO_(3)^(-)-N reach 99.9%and 99.8%,respectively,under 9 mM of C_(0)(HCOOH),pH=3.0,and N_(2) aeration.Meanwhile,96.7%of HCOOH is consumed and converted into gas.The NO_(3)^(-)-N conversion process includes the transformation to NO_(2)^(-)-N,followed by a further reduction to gas and a direct conversion into gas,introducing small amounts of nitrite and ammonia.The carbon dioxide anion radical(·CO_(2)^(-))from HCOOH/HCOO^(-)is the principal cause of NO_(3)^(-)-N reduction by UV/HCOOH/N 2 ARP.In contrast,·CO_(2)^(-)production is caused by the hydroxyl radical(·OH).The NO_(3)^(-)-N reduction efficiency is enhanced by the increase in the light intensity,considerably affected by the initial pH,and less affected by inorganic anions,including Cl^(-),H_(2)PO_(4)^(-),and HCO_(3)^(-)/CO_(3)^(2-).The initial HCOOH concentration and light intensity are the main factors that influence the NO_(3)^(-)-N reduction rate.
基金This work was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences （No.K2009F02） and the National Natural Science Foundation of China-Youth Science Foundation （No.20603039）. The authors thank Dr. Jing Leng, Shn-yan Du, Wen-ming Tian, and Jun-hui Wang for their helpful discussions in the experiment.
文摘Deleterious chlorine fluorescence was found to occur at the same frequency as the Raman scattering of 02 （1 A） and 02 （3 E）, seriously affecting the 02 （1 A） yield measurement in the reaction of chlorine with basic hydrogen peroxide by use of the Raman spectroscopy technique. To solve this problem we have taken advantage of the fact that Raman radiation is always strongly polarized while fluorescence is essentially non-polarized in a gaseous medium. When chlorine utilization of a singlet oxygen generator is 88%, 02（1A） yield reaches （42.4±7.4）% with the effect of chlorine fluorescence completely eliminated.
基金funded by the National Natural Science Foundation of China (31270625)
文摘As a bio-recalcitrant organic pollutant in paper mill effluent, lignin is generally removed by an advanced oxidation process, such as a TiO2/H2O2 photocatalytic technique under irradiation with ultraviolet light, which only accounts for less than 5% of sunlight. Herein, we reported a TiO2/H2O2-based thermally-assisted photocatalytic process that allows lignin to be efficiently degraded under visible/near-infrared light at an elevated temperature. Adsorption of H2O2 on TiO2 nanoparticles and an increase of temperature facilitate the production and separation of charge carriers under near-infrared and visible light irradiation, accelerate carrier transfer at the TiO2-electrolyte interface and promote the production of hydroxyl radicals, A higher level of H2O2 addition results in an increased degradation rate of lignin,while the optimal temperature for the thermally-assisted photodegradation of lignin is 70℃. A charge carrier excitation and transfer process was proposed for the TiO2/H2O2, thermally-assisted photocatalytic process. This work describes a new method for the photodegradation of organic pollutants,such as residual lignin in paper mill effluent, using wide band gap semiconductors under visible and near-infrared light irradiation.
基金supported in part by the National Key Technology R&D Program of China(Nos.2013BAK06B04 and 2014BAD08B03)the National Natural Science Foundation of China(Nos.61307124 and 11404129)+2 种基金the Science and Technology Department of Jilin Province of China(Nos.20120707 and 20140307014SF)the Changchun Municipal Science and Technology Bureau(Nos.11GH01 and 14KG022)the State Key Laboratory of Integrated Optoelectronics,Jilin University(No.IOSKL2012ZZ12)
文摘A differential carbon monoxide(CO) concentration sensing device using a self-fabricated spherical mirror(e.g.light-collector) and a multi-pass gas-chamber is presented in this paper.Single-source dual-channel detection method is adopted to suppress the interferences from light source,optical path and environmental changes.Detection principle of the device is described,and both the optical part and the electrical part are developed.Experiments are carried out to evaluate the sensing performance on CO concentration.The results indicate that at 1.013×10~5 Pa and 298 K,the limit of detection(LoD) is about 11.5 mg/m^3 with an absorption length of 40 cm.As the gas concentration gets larger than115 mg/m^3(1.013×10~5 Pa,298 K),the relative detection error falls into the range of-1.7%—+1.9%.Based on 12 h long-term measurement on the 115 mg/m^3 and 1 150 mg/m^3 CO samples,the maximum detection errors are about0.9%and 5.5%,respectively.Due to the low cost and competitive characteristics,the proposed device shows potential applications in CO detection in the circumstances of coal-mine production and environmental protection.
