In order to improve the destruction efficiency of dioxins and also for developing new dioxin control technology, the destruction mechanisms of 2,3,7,8-tetrachlorodihenzo-p-dioxin （2,3,7,8-TCDD） by O3 and NO3, were i...In order to improve the destruction efficiency of dioxins and also for developing new dioxin control technology, the destruction mechanisms of 2,3,7,8-tetrachlorodihenzo-p-dioxin （2,3,7,8-TCDD） by O3 and NO3, were investigated employing quantum chemical calculations. For involved reactions, the microcosmic reaction processes were analyzed and depicted in detail based on geometry optimizations made by the B3LYP/6-31G（d） method. At the same time, the reaction activation energies were also calculated at the MP2/6- 311G（d,p）//B3LYP/6-31G（d） level. Configuration analysis indicated that 2,3,7,8-TCDD could be destroyed by 03 and NO3 in two different ways. The destruction of 2,3,7,8-TCDD by 03 proceeded via the addition of 03 and the cleavage of C=C while the destruction of 2,3,7,8-TCDD by NO3 proceeded via the substitution of chlorine by NO3. Calculated results show that, the activation energy of the destruction reaction of 2,3,7,8-TCDD by NO3 （267.48 kJ/mol） is much larger than that of the destruction reaction of 2,3,7,8-TCDD by O3 （51.20 kJ/mol）. This indicated that the destruction of 2,3,7,8-TCDD by 03 is much more efficient than that of 2,3,7,8-TCDD by NO3. The reason why the activation energy for the destruction reaction of 2,3,7,8-TCDD by NO3 is so large, is also discussed.展开更多
Bacillus mucilaginosus was used in pretreatment ofpyrolusite to facilitate the flotation removal of quartz from pyrolusite minerals. Quartz was activated by B. mucilaginosus, whereas pyrolusite was unaffected at pH 7 ...Bacillus mucilaginosus was used in pretreatment ofpyrolusite to facilitate the flotation removal of quartz from pyrolusite minerals. Quartz was activated by B. mucilaginosus, whereas pyrolusite was unaffected at pH 7 with laurylamine as collector. Flotation recovery of pyrolusite with B. mucilaginosus pretreatment is 73.62%, slightly lower than that of the process without biopretreament, namely 74.70%. The grade of concentrate of recovered pyrolusite is 19.44%, 2.18% higher than that of the recovered pyrolusite without B. mucilaginosus pretreatment （17.26%）. The results of FTIR and SEM showed that no bacteria were adsorbed on the surface of quartz or pyrolusite, indicating that the better selectivity and collectability of flotation resulted from bacterial byproducts. And interaction of bacterial byproducts such as extracellular bacterial polysaccharide, extracellular bacterial protein and acetic acid, on minerals were studied by FTIR and adsorption.展开更多
The collecting performances of N-dodecylethylene-diamine （ND） to quartz and hematite were studied via single mineral flotation. Experimental results show that ND has stronger collecting ability to quartz than hemati...The collecting performances of N-dodecylethylene-diamine （ND） to quartz and hematite were studied via single mineral flotation. Experimental results show that ND has stronger collecting ability to quartz than hematite. Different floatability of quartz and hematite was presented in the existence of depressant. Compared with lauryl amine, ND has stronger collecting performances to quartz. Satisfied separation result of artificially mixed sample was acquired with iron grade of concentrate of 59.92% and iron recovery of 88.85% when pulp pH value was 7.27 with 41.7 mg/L collector and 3.33 mg/L starch. Polar group properties calculation results indicated that ND has stronger collecting capability and better selectivity than lauryl amine. Measurement results of zeta-potentials and infrared spectrum showed that hydrogen bonding adsorption and electrostatic adsorption occur between the surface of ND and quartz.展开更多
With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission c...With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission concentrations of dioxin are 0.287 0.258 and 0.217 ng-TEQ/m3, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 flee of urea. With an increase of the urea content, the concentration of SO2 emission reduces sharply. （NH4）2SO4, formed by the reaction of SO2 and NH3, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO~ emission presents an increasing trend because the reaction of NH3 and 02 at high temperature produces NOx. Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.展开更多
Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (...Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (SPR) chip. By using this chip in a homemade SPR immunosensor, low molecular weight compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) can be detected at a low level of 0.01 ng/mL. There is a good linear relationship(R2 =0.943 1) between the results of SPR biosensor and enzyme-linked immunosorbent assay(ELISA).展开更多
In order to investigate the effect of butanol on quartz flotation when N-dodecyl ethylenediamine(ND)was used as collector, single mineral flotation and artificial mixed mineral(hematite and quartz were mixed at a mass...In order to investigate the effect of butanol on quartz flotation when N-dodecyl ethylenediamine(ND)was used as collector, single mineral flotation and artificial mixed mineral(hematite and quartz were mixed at a mass ratio of 3:2) separation were conducted in the laboratory. Experimental results indicated that addition of butanol could improve the collecting performance of ND on quartz and enhance the floatability of quartz. Best flotation recovery of quartz was obtained when butanol was mixed with ND at a mass ratio of 1:1. Moreover, the molecular structure of alcohols had a significant effect on mineral recovery. Best separation efficiency could be obtained when tert-butanol was added as it had the largest cross-sectional area. Zeta potential measurements indicated that alcohols could strengthen electrostatic adsorption between quartz and collector. Molecular dynamic simulations revealed that co-adsorption of alcohols along with ND had taken place on the quartz surface, and ND/tert-butyl combinations were more easily absorbed on the quartz surface.展开更多
The strong collecting performance of N-laurel-1,3-diaminopropane（ND13） with respect to quartz encouraged us to study its separation of hematite and quartz mixtures in a laboratory cell flotation test The results sho...The strong collecting performance of N-laurel-1,3-diaminopropane（ND13） with respect to quartz encouraged us to study its separation of hematite and quartz mixtures in a laboratory cell flotation test The results show that the best separation results can be achieved when the pulp pH is 7.27 and 58.3 mg/L collector plus 6.67 mg/L depressant are added to the mixture.Products with 58.45%,62.78%and 63.72% iron grades can be achieved respectively when mass ratio of hematite to quartz is 2：3,1：1,and 3：2.The adsorption mechanism of ND13 on a quartz surface was investigated by zeta-potential and X-ray photoelectron spectroscopy measurements.The results reveal that electrostatic and hydrogen bonding adsorption take place between ND13 and the quartz surface,and that ND13 mainly interacts with the oxygen atoms on the quartz surface.展开更多
文摘In order to improve the destruction efficiency of dioxins and also for developing new dioxin control technology, the destruction mechanisms of 2,3,7,8-tetrachlorodihenzo-p-dioxin （2,3,7,8-TCDD） by O3 and NO3, were investigated employing quantum chemical calculations. For involved reactions, the microcosmic reaction processes were analyzed and depicted in detail based on geometry optimizations made by the B3LYP/6-31G（d） method. At the same time, the reaction activation energies were also calculated at the MP2/6- 311G（d,p）//B3LYP/6-31G（d） level. Configuration analysis indicated that 2,3,7,8-TCDD could be destroyed by 03 and NO3 in two different ways. The destruction of 2,3,7,8-TCDD by 03 proceeded via the addition of 03 and the cleavage of C=C while the destruction of 2,3,7,8-TCDD by NO3 proceeded via the substitution of chlorine by NO3. Calculated results show that, the activation energy of the destruction reaction of 2,3,7,8-TCDD by NO3 （267.48 kJ/mol） is much larger than that of the destruction reaction of 2,3,7,8-TCDD by O3 （51.20 kJ/mol）. This indicated that the destruction of 2,3,7,8-TCDD by 03 is much more efficient than that of 2,3,7,8-TCDD by NO3. The reason why the activation energy for the destruction reaction of 2,3,7,8-TCDD by NO3 is so large, is also discussed.
基金Projects(21176026,21176242)supported by the National Natural Science Foundation of ChinaProject(2012AA062401)supported bythe Hi-tech Research and Development Program of China
文摘Bacillus mucilaginosus was used in pretreatment ofpyrolusite to facilitate the flotation removal of quartz from pyrolusite minerals. Quartz was activated by B. mucilaginosus, whereas pyrolusite was unaffected at pH 7 with laurylamine as collector. Flotation recovery of pyrolusite with B. mucilaginosus pretreatment is 73.62%, slightly lower than that of the process without biopretreament, namely 74.70%. The grade of concentrate of recovered pyrolusite is 19.44%, 2.18% higher than that of the recovered pyrolusite without B. mucilaginosus pretreatment （17.26%）. The results of FTIR and SEM showed that no bacteria were adsorbed on the surface of quartz or pyrolusite, indicating that the better selectivity and collectability of flotation resulted from bacterial byproducts. And interaction of bacterial byproducts such as extracellular bacterial polysaccharide, extracellular bacterial protein and acetic acid, on minerals were studied by FTIR and adsorption.
基金Projects (2008BAB32B14, 2008BAB31B03) supported by the National Key Technology R&D Program of China Project (51004027) supported by the National Natural Science Foundation of China
文摘The collecting performances of N-dodecylethylene-diamine （ND） to quartz and hematite were studied via single mineral flotation. Experimental results show that ND has stronger collecting ability to quartz than hematite. Different floatability of quartz and hematite was presented in the existence of depressant. Compared with lauryl amine, ND has stronger collecting performances to quartz. Satisfied separation result of artificially mixed sample was acquired with iron grade of concentrate of 59.92% and iron recovery of 88.85% when pulp pH value was 7.27 with 41.7 mg/L collector and 3.33 mg/L starch. Polar group properties calculation results indicated that ND has stronger collecting capability and better selectivity than lauryl amine. Measurement results of zeta-potentials and infrared spectrum showed that hydrogen bonding adsorption and electrostatic adsorption occur between the surface of ND and quartz.
基金Project(50904001) supported by the National Natural Science Foundation of ChinaProject(2010SQRL032D) supported by Anhui Provincial Key Science Foundation for Outstanding Young Talent,ChinaProject(TD200909) supported by Program for Innovative Research Team in Anhui University of Technology,China
文摘With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission concentrations of dioxin are 0.287 0.258 and 0.217 ng-TEQ/m3, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 flee of urea. With an increase of the urea content, the concentration of SO2 emission reduces sharply. （NH4）2SO4, formed by the reaction of SO2 and NH3, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO~ emission presents an increasing trend because the reaction of NH3 and 02 at high temperature produces NOx. Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.
基金Supported by the National Natural Science Foundation of Tianjin (No. 09JCZDJC25700, 12JCZDJC29600 and KJXH2011-11)
文摘Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (SPR) chip. By using this chip in a homemade SPR immunosensor, low molecular weight compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) can be detected at a low level of 0.01 ng/mL. There is a good linear relationship(R2 =0.943 1) between the results of SPR biosensor and enzyme-linked immunosorbent assay(ELISA).
基金financial support of the National Natural Science Foundation of China (No.51374051)the Fundamental Research Fund for the Central Universities (No.N130401008)
文摘In order to investigate the effect of butanol on quartz flotation when N-dodecyl ethylenediamine(ND)was used as collector, single mineral flotation and artificial mixed mineral(hematite and quartz were mixed at a mass ratio of 3:2) separation were conducted in the laboratory. Experimental results indicated that addition of butanol could improve the collecting performance of ND on quartz and enhance the floatability of quartz. Best flotation recovery of quartz was obtained when butanol was mixed with ND at a mass ratio of 1:1. Moreover, the molecular structure of alcohols had a significant effect on mineral recovery. Best separation efficiency could be obtained when tert-butanol was added as it had the largest cross-sectional area. Zeta potential measurements indicated that alcohols could strengthen electrostatic adsorption between quartz and collector. Molecular dynamic simulations revealed that co-adsorption of alcohols along with ND had taken place on the quartz surface, and ND/tert-butyl combinations were more easily absorbed on the quartz surface.
基金Financial support for this research provided by the National Key Technology Development and Research Programs of China(Nos. 2008BAB32B14 and 2008BAB31B03)
文摘The strong collecting performance of N-laurel-1,3-diaminopropane（ND13） with respect to quartz encouraged us to study its separation of hematite and quartz mixtures in a laboratory cell flotation test The results show that the best separation results can be achieved when the pulp pH is 7.27 and 58.3 mg/L collector plus 6.67 mg/L depressant are added to the mixture.Products with 58.45%,62.78%and 63.72% iron grades can be achieved respectively when mass ratio of hematite to quartz is 2：3,1：1,and 3：2.The adsorption mechanism of ND13 on a quartz surface was investigated by zeta-potential and X-ray photoelectron spectroscopy measurements.The results reveal that electrostatic and hydrogen bonding adsorption take place between ND13 and the quartz surface,and that ND13 mainly interacts with the oxygen atoms on the quartz surface.
