A treatability study of industrial wastewater containing chlorinated nitroaromatic compounds （CNACs） by a catalytic ozonation process （COP） with a modified Mn/Co ceramic catalyst and an aerobic sequencing batch re...A treatability study of industrial wastewater containing chlorinated nitroaromatic compounds （CNACs） by a catalytic ozonation process （COP） with a modified Mn/Co ceramic catalyst and an aerobic sequencing batch reactor （SBR） was investigated. A preliminary attempt to treat the diluted wastewater with a single SBR resulted in ineffective removal of the color, ammonia, total organic carbon （TOC） and chemical oxygen demand （COD）. Next, COP was applied as a pretreatment in order to obtain a bio-compatible wastewater for SBR treatment in a second step. The effectiveness of the COP pretreatment was assessed by evaluating wastewater biodegradability enhancement （the ratio of biology oxygen demand after 5 d （BOD5） to COD）, as well as monitoring the evolution of TOC, carbon oxidation state （COS）, average oxidation state （AOS）, color, and major pollutant concentrations with reaction time. In the COP, the catalyst preserved its catalytic properties even after 70 reuse cycles, exhibiting good durability and stability. The performance of SBR to treat COP effluent was also examined. At an organic loading rate of 2.0 kg COD/（m^3.d）, with hydraulic retention time （HRT）=10 h and temperature （30±2） ℃, the average removal efficiencies of NH3-N, COD, BOD5, TOC, and color in a coupled COP/SBR process were about 80%, 95.8%, 93.8%, 97.6% and 99.3%, respectively, with average effluent concentrations of 10 mg/L, 128 mg/L, 27.5 mg/L, 25.0 mg/L, and 20 multiples, respectively, which were all consistent with the national standards for secondary discharge of industrial wastewater into a public sewerage system （GB 8978-1996）. The results indicated that the coupling of COP with a biological process was proved to be a technically and economically effective method for treating industrial wastewater containing recalcitrant CNACs.展开更多
Micro-scale Al-Zn-Mg/Fe composite powders (MAF) with high reactivity and good storage properties were prepared by reducing iron onto the surface of Al-Zn-Mg alloy powders. Experimental results show that MAF as advance...Micro-scale Al-Zn-Mg/Fe composite powders (MAF) with high reactivity and good storage properties were prepared by reducing iron onto the surface of Al-Zn-Mg alloy powders. Experimental results show that MAF as advanced zero-valent iron are highly effective for degradation of chlorinated organic compounds. The efficiency of degradation for carbon tetrachloride and perchloroethylene is higher than 99% within a period of 2 h. The efficiency of degradation for trichloroethylene by MAF after storing for one month is equivalent to that by freshly prepared nano-size zero-valent iron particles.展开更多
Polyaniline doped with rare earth chloride was synthesized in organic solvent and identified by elemental analysis and infrared spectroscopy. The experimental results show that there exists both doping and complexatio...Polyaniline doped with rare earth chloride was synthesized in organic solvent and identified by elemental analysis and infrared spectroscopy. The experimental results show that there exists both doping and complexation at the same time in the resulting product. When pH4. Moreover, polyaniline doped with rare earth chloride exhibits better thermal stability than that doped with hydrochloric acid.展开更多
The far-IR spectra of ML3·H2O (M=Y, La-Lu; HL=o-chlorobenzoic acid) have been studied, and the wavenumbers of M-O vibrations (νM-O) have been assigned. It is found that ν-O increases as the atomic number o...The far-IR spectra of ML3·H2O (M=Y, La-Lu; HL=o-chlorobenzoic acid) have been studied, and the wavenumbers of M-O vibrations (νM-O) have been assigned. It is found that ν-O increases as the atomic number of lanthanide element increase. Moreover, the plot of νM-O-L (L is the total orbital angular quantum number of lanthanide ion in ground state) shows an inclined W systematics.展开更多
The cyclic voltammetry, electrode potential-time curve after potentiostatic electrolysis, potential-step method and X-ray diffraction were used to study the electrochemical reaction of Dy (III) in NaCl-KCl equimolar m...The cyclic voltammetry, electrode potential-time curve after potentiostatic electrolysis, potential-step method and X-ray diffraction were used to study the electrochemical reaction of Dy (III) in NaCl-KCl equimolar mixture on Ni electrode. The DyNi5 forms at first and then the intermetallic compounds of DyNi containing more Dy form in sequence. The metallic Dy deposits at last. The standard free energy of formation for DyNi5 determined is -125.6 kJ/mol at 973K. The diffusion coefficient of Dy into DyNi5 phase determined is 8×0-10 cm2/s at 1032 K. The diffusion activation energy of Dy atoms in its intermetallic compound is 101.3 kJ/mol at 973K.展开更多
To study the effects of various concentrations of SmCl3 on the morphology and functions of porcine thyroid cells in vitro, the methods of the electron microscope and radioimmunoassay were used. The investigation showe...To study the effects of various concentrations of SmCl3 on the morphology and functions of porcine thyroid cells in vitro, the methods of the electron microscope and radioimmunoassay were used. The investigation showed that when the thyroid cells were cultured in the presence of 0.001 and 0.01 mmol/L SmCl3, the measured levels of tetraiodothyronine (T4) were much higher than those in control cells and iodine uptake by thyroid cells increased, and the cells appeared to be active functional morphology under the electron microscope. When the thyroid cells were cultured in the presence of 0.1 mmol/L SmCl3, the levels of T4 and iodine uptake by cells decreased as compared with those in control cells, and the morphological changes of the cells presented an inactive functional state. From the evidences mentioned above, it demonstrates that very low concentrations (0.001 and 0.01 mmol/L) of SmCl3 promote synthesis and secretion of thyroid hormone, whereas a higher concentration (0.1 mmol/L of SmCl3) inhibits the synthesis and secretion of thyroid hormone.展开更多
A novel biopolymer, deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-HCTAC), is used as the core layer material in optical waveguide, and the cleanroom technology is successfully applied to fabricate the...A novel biopolymer, deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-HCTAC), is used as the core layer material in optical waveguide, and the cleanroom technology is successfully applied to fabricate the single-mode channel waveguides with low propagation loss. The prepared DNA-HCTAC material shows high optical quality at the optical telecommunication wavelengths, such as high transparency, relatively high refractive index and low birefringence. In the fabrication approach, polymethyl methacrylate (PMMA) is used as a barrier layer to protect the DNA-HCTAC material from the corrosive of photoresist developer, and the etching conditions are optimized to form the smooth wall and sharp cross-section of the waveguide. Lastly, the optical characteristics of DNA-HCTAC channel waveguides are measured. The results show that the DNA-HCTAC waveguide operates with single-mode propagation and has a low optical loss.展开更多
High-surface-area mesoprous powders of γ-Al2O3 doped with Cu^2＋, Cr^3＋, and V^3＋ ions were prepared uia a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compoun...High-surface-area mesoprous powders of γ-Al2O3 doped with Cu^2＋, Cr^3＋, and V^3＋ ions were prepared uia a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compounds. The composites retained high surface areas and pore volumes comparable with those of undoped γ-Al2O3 and the presence of the transition metal ions enhanced their surface acidic properties. The catalytic activity of the prepared catalysts in the oxidation of 1,2-dichloroethane （DCE） was studied in the temperature range of 250-400℃. The catalytic activity and product selectivity were strongly dependent on the presence and the type of dopant ion. While Cu^2＋- and Cr^3＋-containing catalysts showed 100% conversion at 300℃ and 350℃, V3＋-containing catalyst showed considerably lower conversion. Furthermore, while the major products of the reactions over γ-alumina were vinyl chloride （C2H3Cl） and hydrogen chloride （HCl） at all temperatures, Cu- and Cr-doped catalysts showed siguiticantly stronger capability for deep oxidation to CO2.展开更多
Chlorinated organic compounds are emerging pollutants of widespread concern because of their toxicity,bioaccumulation,persistence,and lack of adequate regulatory measures.Their abiotic transformation,facilitated by ir...Chlorinated organic compounds are emerging pollutants of widespread concern because of their toxicity,bioaccumulation,persistence,and lack of adequate regulatory measures.Their abiotic transformation,facilitated by iron-bearing minerals,is critical to their natural dissipation in soils and sediments.However,further exploration is needed to understand their underlying mechanisms and potential engineering applications under different redox conditions.This paper reviews the abiotic transformation behaviors and mechanisms of chlorinated organics at the active surface of iron-bearing minerals under anoxic and oxic conditions and summarizes the strategies for enhancing the abiotic transformation efficiency of chlorinated organics.The abiotic transformation rate under oxic conditions can be a few orders of magnitude higher than that under anoxic conditions.Under anoxic conditions,chlorinated organics undergo reductive dechlorination through reductive elimination,hydrogenolysis,dehydrohalogenation,and nucleophilic substitution.A close relationship between the abiotic transformation of chlorinated organics and the production of hydroxyl radicals by iron-bearing minerals under oxic conditions was discovered.Synthetic active iron-bearing minerals,carbonaceous materials,and biological synergy can facilitate abiotic dechlorination under anoxic conditions.Meanwhile,the regulation of redox conditions,the introduction of ligands,and the utilization of coexisting anions are proposed to enhance oxidative degradation.This study is expected to improve the comprehension of the abiotic degradation of chlorinated organics mediated by iron-bearing minerals and provide the theoretical foundation for developing new approaches aimed at addressing chlorinated organic pollution.展开更多
Sand particles textured with multi-walled carbon nanotubes (MWCNTs) can efficiently control the mobility and bioavailability of contaminants found in aquatic sediments. Adsorption measurements for a wide variety of aq...Sand particles textured with multi-walled carbon nanotubes (MWCNTs) can efficiently control the mobility and bioavailability of contaminants found in aquatic sediments. Adsorption measurements for a wide variety of aquatic contaminants (chlorinated hydrocarbons) on MWCNT-textured sand showed orders of magnitude increase in their sorption coefficients compared to traditional materials (sand) when used for physically separating contaminated sediments from overlying water. Molecular dynamics simulations performed on model experimental systems emphasize that the hydrophobic interactions of the MWCNT surfaces play a crucial role in driving the water molecules away, promoting such enhanced contaminant uptake. The MWCNT-textured sand significantly reduced the migration of contaminants from sediments to overlying water and possesses suitable parameters needed for contaminant sequestration and sediment remediation technologies. The single step and scalable procedure described here for synthesizing robust MWCNT-textured sand surfaces will provide important improvements in the field of remediation/aquatic environment restoration technologies.展开更多
The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degra...The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image. By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then. Gradient- loading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading. Compared with the approach using least square filtering, its peak signal-to-noise ratio （PSNR） is improved from 3.18 to 6.46 dB, while the computing time is reduced to 1/2 - 1/3. Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.展开更多
Electrochemical dechlorination reaction(EDR)is a promising,environmentally friendly,and economically profitable technology for treating chlorinated organic pollutants.For efficient environmental protection,electrocata...Electrochemical dechlorination reaction(EDR)is a promising,environmentally friendly,and economically profitable technology for treating chlorinated organic pollutants.For efficient environmental protection,electrocatalysts with high stability and low cost are of extremely significance to the development of EDR technology.Carbon-based materials have aroused broad interest as electrocatalysts for many electrochemical reactions due to their characteristics including large specific surface area,controllable structure,good conductivity,and chemical stability.For EDR,the carbon-based materials also show many unique superiorities,like strong adsorption capacity to chlorinated organic compounds(COCs),excellent catalytic activity and stability,and environmental compatibility.This review starts with a detailed summary on the mechanisms of electrochemical dechlorination(direct and indirect electron transfer pathway)and factors affecting the effectiveness of EDR.Then the paper comprehensively overviews the current progresses of carbon-based materials for EDR of COCs,following their two major application scenarios,i.e.,directly as electrocatalysts and as advanced supports for other catalysts.Moreover,the formation of different active sites in carbon-based electrocatalysts and their EDR activities are analyzed.Finally,the current challenges and perspectives in this field are discussed.This review will provide an in-depth understanding for the design of advanced carbon-based materials and promote the development of EDR technology.展开更多
Localized modes in one-dimensional （1D） media with uniaxial scatterers that are assumed to be order in spatial location but disorder in spatial orientation of their optical axis are investigated. Based on the holist...Localized modes in one-dimensional （1D） media with uniaxial scatterers that are assumed to be order in spatial location but disorder in spatial orientation of their optical axis are investigated. Based on the holistic effect model in random laser, i.e., the random laser is due to the interaction of the complex localized modes in active random media with local aperiodic quasi-structure with appropriate pump light, a physical model on this type of random media is found. Its disorder degree is defined by D = no/ne. Then, the typical transmission spectrum through the random media and the light field intensity distribution corresponding to the defect modes in photonic band-gap are calculated numerically by means of the transfer matrix method, and the condition that the localized mode appears is discussed. Results show that the medium disorder plays an important role in determining the lightwave state. The localized state appears when the medium disorder is strong enough, and a new mechanism creating random laser phenomenon is brought forward.展开更多
Direct mass spectrometric analysis of complex biological samples is very important and challenging. In this paper, nanodiamonds have been successfully used in matrix-assisted laser desorption/ionization mass spectrome...Direct mass spectrometric analysis of complex biological samples is very important and challenging. In this paper, nanodiamonds have been successfully used in matrix-assisted laser desorption/ionization mass spectrometric analysis of human serum and urine. As a practical tool and platform, it can be widely used in the field of humoral proteomics, and it plays a very promising role in clinical diagnosis, including identification of novel disease-associated biomarkers.展开更多
In trace Li analysis with degenerate four-wave mixing （DFWM） method, acid anions and major metallic elements are dominant interferences in Li-eontaining samples. To better use DFWM technique to analyze trace Li in a...In trace Li analysis with degenerate four-wave mixing （DFWM） method, acid anions and major metallic elements are dominant interferences in Li-eontaining samples. To better use DFWM technique to analyze trace Li in actual samples, we study their effects on Li DFWM signal intensity. It is found that K, Cs, and Ni can enhance the Li DFWM signal, SO4^2, PO^34-, Cl-, and Ca can cause significant suppression, and NO3-, Mg, Ba, Sr, and Na almost have no effects. Finally, we use HaBOa to eliminate the depressive effects of chlorides on Li DFWM signal. The result is also of reference in other trace elements analysis with DFWM.展开更多
We use an electrostatic model to study the average kinetic energy of ions ejected from the pure Coulomb explosions of methane clusters （CA4）n （light atom A=H and D）. It is found that the ratio of the average kinet...We use an electrostatic model to study the average kinetic energy of ions ejected from the pure Coulomb explosions of methane clusters （CA4）n （light atom A=H and D）. It is found that the ratio of the average kinetic energy of the ions to their initial average electrostatic potential energy is irrelevant to the cluster size. This finding implies that as long as the ratio is given, the average kinetic energies of the ions can be simply estimated from their initial average electrostatic potential energies, rather than from the timeconsuming simulations. The ratios for the different charge states of carbon ions are presented.展开更多
Oxidation within the system CCl4/CH4/O2/N2 is studied at atmospheric pressure in a tubular flow reactor to investigate the influence of reaction temperature and chlorine content on chlorinated waste combustion and fin...Oxidation within the system CCl4/CH4/O2/N2 is studied at atmospheric pressure in a tubular flow reactor to investigate the influence of reaction temperature and chlorine content on chlorinated waste combustion and find incineration process optimization methods for pollution control.The reaction temperature varies from 700℃to 1000℃and the CCl4/CH4(or Cl/H)mole ratio of the inlet mixture varies from 0.21 to 0.84.Products profiles are measured with FT-IR.It is shown that at the same initial CCl4 concentration and reaction temperature adding CH4 favors CCl4 destruction and CO2 formation.But the destruction and removal efficiency(DRE)of CH4 decreases with lower Cl/H and higher concentrations of toxic products of incomplete combustion such as COCl2 and CH3Cl are formed at the same time.The chlorine in the system favors CH4 decomposition,but it also inhibits further oxidation of CO.Higher temperature assists in both CCl4 destruction and CH4 conversion,and the concentration of toxic combustion intermediates is reduced.Increasing the temperature is the most effective way to enhance CCl4 oxidation.The CO2 concentration increases with temperature.A CO concentration peak is observed around 800℃:with a certain Cl/H,the CO concentration first increases with temperature and then declines.The effect of increasing CH4 concentration on CCl4 destruction becomes mild above 900℃.Rather,it enhances the interaction between chlorine and carbonaceous radicals,which leads to higher concentration of toxic products.展开更多
基金Project supported by the National Natural Science Foundation of China (No.50378082)the Key Project of Science and Technology Plan of Zhejiang Province (No.2004C23021),China
文摘A treatability study of industrial wastewater containing chlorinated nitroaromatic compounds （CNACs） by a catalytic ozonation process （COP） with a modified Mn/Co ceramic catalyst and an aerobic sequencing batch reactor （SBR） was investigated. A preliminary attempt to treat the diluted wastewater with a single SBR resulted in ineffective removal of the color, ammonia, total organic carbon （TOC） and chemical oxygen demand （COD）. Next, COP was applied as a pretreatment in order to obtain a bio-compatible wastewater for SBR treatment in a second step. The effectiveness of the COP pretreatment was assessed by evaluating wastewater biodegradability enhancement （the ratio of biology oxygen demand after 5 d （BOD5） to COD）, as well as monitoring the evolution of TOC, carbon oxidation state （COS）, average oxidation state （AOS）, color, and major pollutant concentrations with reaction time. In the COP, the catalyst preserved its catalytic properties even after 70 reuse cycles, exhibiting good durability and stability. The performance of SBR to treat COP effluent was also examined. At an organic loading rate of 2.0 kg COD/（m^3.d）, with hydraulic retention time （HRT）=10 h and temperature （30±2） ℃, the average removal efficiencies of NH3-N, COD, BOD5, TOC, and color in a coupled COP/SBR process were about 80%, 95.8%, 93.8%, 97.6% and 99.3%, respectively, with average effluent concentrations of 10 mg/L, 128 mg/L, 27.5 mg/L, 25.0 mg/L, and 20 multiples, respectively, which were all consistent with the national standards for secondary discharge of industrial wastewater into a public sewerage system （GB 8978-1996）. The results indicated that the coupling of COP with a biological process was proved to be a technically and economically effective method for treating industrial wastewater containing recalcitrant CNACs.
文摘Micro-scale Al-Zn-Mg/Fe composite powders (MAF) with high reactivity and good storage properties were prepared by reducing iron onto the surface of Al-Zn-Mg alloy powders. Experimental results show that MAF as advanced zero-valent iron are highly effective for degradation of chlorinated organic compounds. The efficiency of degradation for carbon tetrachloride and perchloroethylene is higher than 99% within a period of 2 h. The efficiency of degradation for trichloroethylene by MAF after storing for one month is equivalent to that by freshly prepared nano-size zero-valent iron particles.
文摘Polyaniline doped with rare earth chloride was synthesized in organic solvent and identified by elemental analysis and infrared spectroscopy. The experimental results show that there exists both doping and complexation at the same time in the resulting product. When pH4. Moreover, polyaniline doped with rare earth chloride exhibits better thermal stability than that doped with hydrochloric acid.
文摘The far-IR spectra of ML3·H2O (M=Y, La-Lu; HL=o-chlorobenzoic acid) have been studied, and the wavenumbers of M-O vibrations (νM-O) have been assigned. It is found that ν-O increases as the atomic number of lanthanide element increase. Moreover, the plot of νM-O-L (L is the total orbital angular quantum number of lanthanide ion in ground state) shows an inclined W systematics.
文摘The cyclic voltammetry, electrode potential-time curve after potentiostatic electrolysis, potential-step method and X-ray diffraction were used to study the electrochemical reaction of Dy (III) in NaCl-KCl equimolar mixture on Ni electrode. The DyNi5 forms at first and then the intermetallic compounds of DyNi containing more Dy form in sequence. The metallic Dy deposits at last. The standard free energy of formation for DyNi5 determined is -125.6 kJ/mol at 973K. The diffusion coefficient of Dy into DyNi5 phase determined is 8×0-10 cm2/s at 1032 K. The diffusion activation energy of Dy atoms in its intermetallic compound is 101.3 kJ/mol at 973K.
文摘To study the effects of various concentrations of SmCl3 on the morphology and functions of porcine thyroid cells in vitro, the methods of the electron microscope and radioimmunoassay were used. The investigation showed that when the thyroid cells were cultured in the presence of 0.001 and 0.01 mmol/L SmCl3, the measured levels of tetraiodothyronine (T4) were much higher than those in control cells and iodine uptake by thyroid cells increased, and the cells appeared to be active functional morphology under the electron microscope. When the thyroid cells were cultured in the presence of 0.1 mmol/L SmCl3, the levels of T4 and iodine uptake by cells decreased as compared with those in control cells, and the morphological changes of the cells presented an inactive functional state. From the evidences mentioned above, it demonstrates that very low concentrations (0.001 and 0.01 mmol/L) of SmCl3 promote synthesis and secretion of thyroid hormone, whereas a higher concentration (0.1 mmol/L of SmCl3) inhibits the synthesis and secretion of thyroid hormone.
基金supported by the International Collaboration Project of Ningbo (No.2010D10018)the Research and Innovation Project of Zhejiang Province (No.2011R405050)the Research Fund of Graduate of Ningbo University (No.G11JA001)
文摘A novel biopolymer, deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-HCTAC), is used as the core layer material in optical waveguide, and the cleanroom technology is successfully applied to fabricate the single-mode channel waveguides with low propagation loss. The prepared DNA-HCTAC material shows high optical quality at the optical telecommunication wavelengths, such as high transparency, relatively high refractive index and low birefringence. In the fabrication approach, polymethyl methacrylate (PMMA) is used as a barrier layer to protect the DNA-HCTAC material from the corrosive of photoresist developer, and the etching conditions are optimized to form the smooth wall and sharp cross-section of the waveguide. Lastly, the optical characteristics of DNA-HCTAC channel waveguides are measured. The results show that the DNA-HCTAC waveguide operates with single-mode propagation and has a low optical loss.
基金United Arab Emirates University through NRF grant, 2011
文摘High-surface-area mesoprous powders of γ-Al2O3 doped with Cu^2＋, Cr^3＋, and V^3＋ ions were prepared uia a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compounds. The composites retained high surface areas and pore volumes comparable with those of undoped γ-Al2O3 and the presence of the transition metal ions enhanced their surface acidic properties. The catalytic activity of the prepared catalysts in the oxidation of 1,2-dichloroethane （DCE） was studied in the temperature range of 250-400℃. The catalytic activity and product selectivity were strongly dependent on the presence and the type of dopant ion. While Cu^2＋- and Cr^3＋-containing catalysts showed 100% conversion at 300℃ and 350℃, V3＋-containing catalyst showed considerably lower conversion. Furthermore, while the major products of the reactions over γ-alumina were vinyl chloride （C2H3Cl） and hydrogen chloride （HCl） at all temperatures, Cu- and Cr-doped catalysts showed siguiticantly stronger capability for deep oxidation to CO2.
基金supported by the National Natural Science Foundation of China(Grant No.52100180)the Fundamental Research Funds for the Central Universities(Grant No.531118010817).
文摘Chlorinated organic compounds are emerging pollutants of widespread concern because of their toxicity,bioaccumulation,persistence,and lack of adequate regulatory measures.Their abiotic transformation,facilitated by iron-bearing minerals,is critical to their natural dissipation in soils and sediments.However,further exploration is needed to understand their underlying mechanisms and potential engineering applications under different redox conditions.This paper reviews the abiotic transformation behaviors and mechanisms of chlorinated organics at the active surface of iron-bearing minerals under anoxic and oxic conditions and summarizes the strategies for enhancing the abiotic transformation efficiency of chlorinated organics.The abiotic transformation rate under oxic conditions can be a few orders of magnitude higher than that under anoxic conditions.Under anoxic conditions,chlorinated organics undergo reductive dechlorination through reductive elimination,hydrogenolysis,dehydrohalogenation,and nucleophilic substitution.A close relationship between the abiotic transformation of chlorinated organics and the production of hydroxyl radicals by iron-bearing minerals under oxic conditions was discovered.Synthetic active iron-bearing minerals,carbonaceous materials,and biological synergy can facilitate abiotic dechlorination under anoxic conditions.Meanwhile,the regulation of redox conditions,the introduction of ligands,and the utilization of coexisting anions are proposed to enhance oxidative degradation.This study is expected to improve the comprehension of the abiotic degradation of chlorinated organics mediated by iron-bearing minerals and provide the theoretical foundation for developing new approaches aimed at addressing chlorinated organic pollution.
基金ST acknowledges Southern Illinois University Car-bondale(SIUC)Office of Research and Development Administration for providing financial support through start-up funds and a seed grant.
文摘Sand particles textured with multi-walled carbon nanotubes (MWCNTs) can efficiently control the mobility and bioavailability of contaminants found in aquatic sediments. Adsorption measurements for a wide variety of aquatic contaminants (chlorinated hydrocarbons) on MWCNT-textured sand showed orders of magnitude increase in their sorption coefficients compared to traditional materials (sand) when used for physically separating contaminated sediments from overlying water. Molecular dynamics simulations performed on model experimental systems emphasize that the hydrophobic interactions of the MWCNT surfaces play a crucial role in driving the water molecules away, promoting such enhanced contaminant uptake. The MWCNT-textured sand significantly reduced the migration of contaminants from sediments to overlying water and possesses suitable parameters needed for contaminant sequestration and sediment remediation technologies. The single step and scalable procedure described here for synthesizing robust MWCNT-textured sand surfaces will provide important improvements in the field of remediation/aquatic environment restoration technologies.
基金the National Key Lab-oratory Scientific Foundation of Optical Signature of Targets and Environments and Cultivation Fund of the Key Scientific and Technical Project,Ministry of Educa-tion of China (No.706022).
文摘The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image. By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then. Gradient- loading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading. Compared with the approach using least square filtering, its peak signal-to-noise ratio （PSNR） is improved from 3.18 to 6.46 dB, while the computing time is reduced to 1/2 - 1/3. Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.
基金supported by the 2021 Hong Kong Scholars Program(No.XJ2021005)the National Natural Science Foundation of China(Nos.52301261,52372229,and 52172241)+2 种基金the General Research Fund of Hong Kong(Nos.CityU 11308321 and CityU 11315622)the Green Tech Fund(No.GTF202220105)the City University of Hong Kong(No.9020002).
文摘Electrochemical dechlorination reaction(EDR)is a promising,environmentally friendly,and economically profitable technology for treating chlorinated organic pollutants.For efficient environmental protection,electrocatalysts with high stability and low cost are of extremely significance to the development of EDR technology.Carbon-based materials have aroused broad interest as electrocatalysts for many electrochemical reactions due to their characteristics including large specific surface area,controllable structure,good conductivity,and chemical stability.For EDR,the carbon-based materials also show many unique superiorities,like strong adsorption capacity to chlorinated organic compounds(COCs),excellent catalytic activity and stability,and environmental compatibility.This review starts with a detailed summary on the mechanisms of electrochemical dechlorination(direct and indirect electron transfer pathway)and factors affecting the effectiveness of EDR.Then the paper comprehensively overviews the current progresses of carbon-based materials for EDR of COCs,following their two major application scenarios,i.e.,directly as electrocatalysts and as advanced supports for other catalysts.Moreover,the formation of different active sites in carbon-based electrocatalysts and their EDR activities are analyzed.Finally,the current challenges and perspectives in this field are discussed.This review will provide an in-depth understanding for the design of advanced carbon-based materials and promote the development of EDR technology.
基金the National Natural Science Foundation of China under Grant No.10464002 and 60768001.
文摘Localized modes in one-dimensional （1D） media with uniaxial scatterers that are assumed to be order in spatial location but disorder in spatial orientation of their optical axis are investigated. Based on the holistic effect model in random laser, i.e., the random laser is due to the interaction of the complex localized modes in active random media with local aperiodic quasi-structure with appropriate pump light, a physical model on this type of random media is found. Its disorder degree is defined by D = no/ne. Then, the typical transmission spectrum through the random media and the light field intensity distribution corresponding to the defect modes in photonic band-gap are calculated numerically by means of the transfer matrix method, and the condition that the localized mode appears is discussed. Results show that the medium disorder plays an important role in determining the lightwave state. The localized state appears when the medium disorder is strong enough, and a new mechanism creating random laser phenomenon is brought forward.
文摘Direct mass spectrometric analysis of complex biological samples is very important and challenging. In this paper, nanodiamonds have been successfully used in matrix-assisted laser desorption/ionization mass spectrometric analysis of human serum and urine. As a practical tool and platform, it can be widely used in the field of humoral proteomics, and it plays a very promising role in clinical diagnosis, including identification of novel disease-associated biomarkers.
基金supported by the National "973" Plan Preliminary Study Special of China(Nos.2012CB723407 and 2010CB434811)the Northwest University Science Foundation(No.13NW12)the Shaanxi Provincial Department of Education Project(No.12JK0599)
文摘In trace Li analysis with degenerate four-wave mixing （DFWM） method, acid anions and major metallic elements are dominant interferences in Li-eontaining samples. To better use DFWM technique to analyze trace Li in actual samples, we study their effects on Li DFWM signal intensity. It is found that K, Cs, and Ni can enhance the Li DFWM signal, SO4^2, PO^34-, Cl-, and Ca can cause significant suppression, and NO3-, Mg, Ba, Sr, and Na almost have no effects. Finally, we use HaBOa to eliminate the depressive effects of chlorides on Li DFWM signal. The result is also of reference in other trace elements analysis with DFWM.
基金the National Basic Research Program of China(No.2006CB806000)the National Natural Science Foundation of China(No.10535070)
文摘We use an electrostatic model to study the average kinetic energy of ions ejected from the pure Coulomb explosions of methane clusters （CA4）n （light atom A=H and D）. It is found that the ratio of the average kinetic energy of the ions to their initial average electrostatic potential energy is irrelevant to the cluster size. This finding implies that as long as the ratio is given, the average kinetic energies of the ions can be simply estimated from their initial average electrostatic potential energies, rather than from the timeconsuming simulations. The ratios for the different charge states of carbon ions are presented.
文摘Oxidation within the system CCl4/CH4/O2/N2 is studied at atmospheric pressure in a tubular flow reactor to investigate the influence of reaction temperature and chlorine content on chlorinated waste combustion and find incineration process optimization methods for pollution control.The reaction temperature varies from 700℃to 1000℃and the CCl4/CH4(or Cl/H)mole ratio of the inlet mixture varies from 0.21 to 0.84.Products profiles are measured with FT-IR.It is shown that at the same initial CCl4 concentration and reaction temperature adding CH4 favors CCl4 destruction and CO2 formation.But the destruction and removal efficiency(DRE)of CH4 decreases with lower Cl/H and higher concentrations of toxic products of incomplete combustion such as COCl2 and CH3Cl are formed at the same time.The chlorine in the system favors CH4 decomposition,but it also inhibits further oxidation of CO.Higher temperature assists in both CCl4 destruction and CH4 conversion,and the concentration of toxic combustion intermediates is reduced.Increasing the temperature is the most effective way to enhance CCl4 oxidation.The CO2 concentration increases with temperature.A CO concentration peak is observed around 800℃:with a certain Cl/H,the CO concentration first increases with temperature and then declines.The effect of increasing CH4 concentration on CCl4 destruction becomes mild above 900℃.Rather,it enhances the interaction between chlorine and carbonaceous radicals,which leads to higher concentration of toxic products.
