Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determini...Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determining an optimal chlorination scheme are the different responses of crops to the chloride added into the soil through chlorination. During two seasons in 2008 and 2009, field experiments were conducted in a solar-heated greenhouse with drip irrigation systems applying secondary sewage effluent to tomato plants to investigate the influences of chlorine injection intervals and levels on plant growth, yield, fruit quality, and emitter clogging. Injection intervals ranging from 2 to 8 wk and injection concentrations ranging 2-50 mg L-1 of free chlorine residual at the end of the laterals were used. For the 2008 experiments, the yield from the treatments of sewage application with chlorination was 7.5% lower than the yield from the treatment of sewage application without chlorination, while the yields for the treatments with and without chlorination were similar for the 2009 experiments. The statistical tests indicated that neither the chlorine injection intervals and concentrations nor the interactions between the two significantly influenced plant height, leaf area, or tomato yield for both years. The qualities of the fruit in response to chlorination were parameter-dependent. Chlorination did not significantly influence the quality of ascorbic acid, soluble sugar, or soluble acids, but the interaction between the chlorine injection interval and the chlorine concentration significantly influenced the levels of soluble solids. It was also confirmed that chlorination was an effective method for reducing biological clogging. These results suggested that chlorination is safe for a crop that has a moderate sensitivity to chlorine, like tomato, and can maintain a high level of performance in drip irrigation systems applying sewage effluent.展开更多
Bormate (BrO3^-) is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the format...Bormate (BrO3^-) is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions, particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet (UV)/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards (10 μg/L). UV irradiation enhanced the decay of free chlorine, and, simultaneously, 6.6%-32% of Br^- was oxidized to BrO3^-. And the formation of bromate exhibited three stages: rapid stage, slow stage and plateau. Under the experimental conditions (pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L), low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.展开更多
The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results ...The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process,various process parameters were studied,including the roasting temperature,the addition of NH_4 Cl,the roasting time,the leaching time,and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition,95% of Ni,98% of Cu,and 88% of Co were recovered. In addition,the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores.展开更多
The chlorination-volatilization process has been adopted to make full use of gold-bearing and iron-rich pyrite cinder. However, problems of low recovery rate, pulverization of pellets, and ring formation have been enc...The chlorination-volatilization process has been adopted to make full use of gold-bearing and iron-rich pyrite cinder. However, problems of low recovery rate, pulverization of pellets, and ring formation have been encountered during the industrialization of this process. The effects of various parameters on the volatilization rates of valuable metals and on the compressive strength of roasted pellets were investigated in this paper. The parameters include the CaCl_2 dosage, heating temperature, and holding time. The results show that heating temperature is the most important parameter for the recovery of target metals. More CaCl_2 was needed for the recovery of zinc than for the recovery of gold, silver, and lead. CaCl_2 started to react with sulfides/SO_2/SiO_2 at temperatures below the melting point of CaCl_2 to generate Cl_2/HCl. Gaseous CaCl_2 was formed at higher temperatures and could react with any of the components. The compressive strength of roasted CaCl_2-bearing pellets first decreased slowly with increasing temperature at temperatures lower than 873 K, which could result in the pulverization of pellets during heating. Their compressive strength increased dramatically with increasing temperature at temperatures greater than 1273 K. Certain quantities of CaCl_2 and Fe(Ⅱ) could improve the compressive strength of the roasted pellets; however, the addition of excessive CaCl_2 decreased the compressive strength of pellets.展开更多
Bulk heterojunction(BHJ)polymer solar cells(PSCs)are promising candidates for next-generation solar cells.Benefitting from the persistent efforts in material design and synthesis,systematic device engineering and fund...Bulk heterojunction(BHJ)polymer solar cells(PSCs)are promising candidates for next-generation solar cells.Benefitting from the persistent efforts in material design and synthesis,systematic device engineering and fundamental understanding of the device physics,the power conversion efficiency(PCE)of single PSC has been pushed to surpass 15%,and that of the tandem PSCs is over 17%.Recently,chlorination has drawn much interest and the chlorinated PSCs have been frequently reported in donor-acceptor(D-A)type conjugated polymers.This review summarizes the recent progress of the chlorinated strategy for highly efficient photovoltaic applications.We firstly discuss the chlorination on the acceptor units in D-A type donor polymers,emphasizing the 4 widely used acceptor units with their improved PCE.secondly,the chlorination on the donor units will be discussed,mainly focusing on the chlorination of benzo[1,2-b:4,b]dithiophene(BDT)unit and 2,2-bithiophene unit.Remarkably,the PCE of the chlorinated BDT-based device has been improved to over 14%.Overall,this review discusses the structure-property correlations of these chlorinated polymers in photovoltaic study,which could further provide guidance on the chlorinated strategy and the molecular design for high-performance photovoltaic devices.展开更多
A new process of enriching germanium from coal ash was developed. The processinvolves in mixing the coal ash and ammonium chloride and then roasting the mixture to producegermanium chloride that is then absorbed by di...A new process of enriching germanium from coal ash was developed. The processinvolves in mixing the coal ash and ammonium chloride and then roasting the mixture to producegermanium chloride that is then absorbed by dilute hydrochloric acid and hydrolyzed to germaniumoxide. The germanium recovery reached to 80.2% at the optimum condition: mass ratio of NH_4Cl/coalash is 0.15, roasting temperature 400℃ and roasting time 90 min.展开更多
The resources of refractory gold ores are abundant, and their effective treatment can bring good economic benefits. This paper investigated the kinetics of leaching gold from refractory gold ores by ultrasonic-assiste...The resources of refractory gold ores are abundant, and their effective treatment can bring good economic benefits. This paper investigated the kinetics of leaching gold from refractory gold ores by ultrasonic-assisted electro-chlorination. The effects of ultrasound time ratio, initial hydrochloric acid concentration and leaching temperature on the kinetic parameters were discussed. It is found that the leaching ratio goes up with all the factors increasing. The reaction kinetics is controlled by diffusion. When ultrasound improves the diffusion by reducing the diffusion resistance, the activation energy increases to 37.1 kJ/mol.展开更多
Three small-molecule donors based on dithieno [2,3-d:2’,3 ’-d’]-benzo[1,2-b:4,5-b’] dithiophene(DTBDT)unit were designed and synthesized by side chain regulation with chlorinated or/and sulfurated substitutions(na...Three small-molecule donors based on dithieno [2,3-d:2’,3 ’-d’]-benzo[1,2-b:4,5-b’] dithiophene(DTBDT)unit were designed and synthesized by side chain regulation with chlorinated or/and sulfurated substitutions(namely ZR1,ZR1-Cl,and ZR1-S-Cl respectively),along with a crystalline non-fullerene acceptor IDIC-4 Cl with a chlorinated 1,1-dicyanomethylene-3-indanone(IC) end group.Energy levels,molar extinction coefficients and crystallinities of three donor molecules can be effectively altered by combining chlorination and sulfuration strategies.Especially,the ZR1-S-Cl exhibited the best absorption ability,lowest higher occupied molecular orbital(HOMO) energy level and highest crystallinity among three donors,resulting in the corresponding all-small-molecule organic solar cells to produce a high power conversion efficiency(PCE) of 12.05% with IDIC-4 Cl as an acceptor.展开更多
The ion chromatography combined solid phase extraction (SPE) method was developed for the analysis of low concentration haloacetic acids (HAAs), a class of disinfection by-products formed from chlorination of hosp...The ion chromatography combined solid phase extraction (SPE) method was developed for the analysis of low concentration haloacetic acids (HAAs), a class of disinfection by-products formed from chlorination of hospital wastewater. The monitored HAAs included monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, dibromoacetic acid and trichloroacetic acid. The method employed a sodium hydroxide eluent at a flow rate of 0.8 ml/min, electrolytically generated gradients, and suppressed conductivity detection. To analyze the HAAs in real hospital wastewater samples, C18 pretreatment cartridge was utilized to reduce samples' turbidity. Preconcentration with SPE and matrix elimination with treatment cartridges were investigated and found to be able to obtain acceptable detection limits. Linearity, repeatability and detection limits of the above method were evaluated. The detection limits of monobromoacetic acid and dibromoacetic acid were 2.61 μg/L and 1.30 μg/L, respectively, and the other three acids are ranging from 0.48 to 0.82μg/L under 25-fold preconcentration. When the above optimization procedure was applied to three hospital wastewater samples with different treatment processes in Tianjin, it was found that the dichloroacetic acid was the major compound, and the growth ratios of the HAAs after disinfection by sodium hypochlorite were 91.28%, 63.61% and 79.50%, respectively.展开更多
The present paper reports the effective utilization of marble sludge powder(MSP)for the recovery of potash values from waste mica scrap using chlorination roasting-water leaching method.Characterization studies indica...The present paper reports the effective utilization of marble sludge powder(MSP)for the recovery of potash values from waste mica scrap using chlorination roasting-water leaching method.Characterization studies indicated the presence of dolomite as the major mineral phase in MSP,whereas muscovite and quartz were observed in the mica sample.The acid leaching studies suggest a maximum of 22%potash recovery under conditions:4 M H2SO4 acid,particle size of^100μm,stirring speed of 600 r/min,leaching temperature of 75℃,and leaching time of 90 min.The chlorination roasting-water leaching process was adopted to achieve the lowest level of 80%-90%potash recovery.The optimum conditions for the recovery of^93%potash from mica(~8.6wt%K2O)requires 900℃ roasting temperature,30 min roasting time,and 1:1:0.75 mass ratio of mica:MSP:NaCl.The roasting temperature and amount of NaCl are found to be the most important factors for the recovery process.The reaction mechanism suggests the formation of different mineral phases,including sylvite(KCl),wollastonite,kyanite,and enstatite,during roasting,which were confirmed by X-ray diffraction(XRD)analyses and scanning electron microscopy(SEM)morphologies.The MSP-blended NaCl additive is more effective for potash recovery compared with the other reported commercial roasting additives.展开更多
Objective To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Esch...Objective To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.展开更多
Haloacetic acids(HAAs) are formed during the chlorination of drinking water,which are harmful to people′s health due to their carcinogenic and mutagenic effects. In the present study,a detection method combining meth...Haloacetic acids(HAAs) are formed during the chlorination of drinking water,which are harmful to people′s health due to their carcinogenic and mutagenic effects. In the present study,a detection method combining methyl tert -butyl ether(MtBE) extraction with acid catalysis and gas chromatography coupled with an electron capture detector(GC/ECD) was developed for determining HAAs. The detection limit of this method(MDL) and relative standard deviation(RSD) were below 0.37 μg/L and 6.2%,respectively. The laboratory chlorination experiments were conducted with the purpose of investigating the influences of reaction time,temperature,UV_ 254 ,bromide and ammonia-nitrogen on the formation of HAAs. The results show that the formation amount of HAAs increases with increasing reaction time and temperature,respectively;and there exists a linear relationship between the formation of HAAs and UV_ 254 . The formation amount of HAAs decreases first and then increases as the bromide ion concentration increases,and adding NH +_4 is a possible way to control the formation of HAAs.展开更多
Chlorination is usually an economical method for treating clogging in drip emitters during sewage application. Appropriate assessment of the responses of soil and crop is essential for determining an optimal chlorinat...Chlorination is usually an economical method for treating clogging in drip emitters during sewage application. Appropriate assessment of the responses of soil and crop is essential for determining an optimal chlorination scheme. During 2008 to 2009, field experiments were conducted in a solar-heated greenhouse for tomato drip irrigated with secondary sewage effluent, to investigate the influences of chlorine injection intervals and levels on soil chemical properties and nitrogen uptake. Injection intervals ranging from two to eight weeks and injection concentrations ranging from 2 to 50 mg L-1 were used. A salinity factor and a nutrient factor were extracted from the pool of the nine soil chemical constituents using factor analysis method. The results demonstrated that chlorination practices increased the residual Cl in the soil, resulting in an increased salinity factor, especially for the frequent chlorination at a high injection concentration. Chlorination weakened the accumulation of nutrients factor in the upper soil layer. Nitrogen uptake of the tomato plants also was inhibited by the increased salinity in the upper soil layer caused by high chlorination levels. In order to reduce the unfavorable effect on soil chemical properties and nitrogen uptake, chlorination scheme with concentrations of lower than 20 mg L-1 was recommended.展开更多
The use of seawater for industrial cooling is a vital technology that poses some of the most profound environmental impact on the water quality in the Arabian Gulf. Biocide (chlorine) is added to the seawater to contr...The use of seawater for industrial cooling is a vital technology that poses some of the most profound environmental impact on the water quality in the Arabian Gulf. Biocide (chlorine) is added to the seawater to control biofouling of the cooling system. This added chlorine reacts with bromide and other chemicals naturally exist in the water to form a wide range of oxidants. Regrettably, reactions between the residual oxidants and natural organic matter in the water lead to formation of toxic halogenated organic compounds that have detrimental effects on the environment when they are discharged into the Gulf. This paper describes the formation of trihalomethanes (THMs) in seawater cooling systems. Results of kinetic experiments have shown that concentrations of THMs increased rapidly with time during the first half hour. Chlorination of seawater has shown significant increase in total THMs (TTHMs) and in bromoform concentrations. Rapid decrease of UV absorbance at 254 nm was also observed during seawater chlorination which is indicative of natural organic matter degradation into small organic molecules including THMs and other by-products. The increase in chlorine dose was accompanied with an increase in TTHMs and bromoform concentrations. Linear relationships between total chlorine concentration and both final TTHMs and bromoform concentrations were established. First order exponential decay and exponential associate functions were developed to correlate chlorine dose with formed THMs.展开更多
For a chlorinating method at low temperature, the possibility of chlorination of Nd2O3 by a mechanochemical reaction with CCl4 was studied using a planetary ball mill. The mechanochemical experiments were conducted by...For a chlorinating method at low temperature, the possibility of chlorination of Nd2O3 by a mechanochemical reaction with CCl4 was studied using a planetary ball mill. The mechanochemical experiments were conducted by changing the pot materials, milling time, molar ratio of CCl4/Nd2O3, and revolution speed. As the results of obtained products by X-ray diffractometry and Raman spectroscopy, it was confirmed that the chlorination to NdOCl from Nd2O3 with CCl4 was advanced at room temperature in a zirconia or tungsten pot with balls. We found that an extension of the milling time and an increase of the number of ball were effective to the chlorination to NdOCl and that tensile stress remained in the milled powder by using a planetary ball mill.展开更多
Isoindigo(IID)has been widely used as strong acceptor unit(A)to construct narrow bandgap polymers in organic field effect transistors(OFETs)and organic solar cells(OSCs).Combing with IID,we chose benzodithiophene(BDT)...Isoindigo(IID)has been widely used as strong acceptor unit(A)to construct narrow bandgap polymers in organic field effect transistors(OFETs)and organic solar cells(OSCs).Combing with IID,we chose benzodithiophene(BDT)as the donor unit(D)and thieno[3,2-b]thiophene(TT)as theπbridge to construct a new type of D-π-A polymer PE70.Based on PE70,we adopt the chlorination strategy to fine-tune photoelectric characteristics and film morphology,and then developed PE74 and PE75.By blending with non-fullerene acceptor(NFA)Y6,device based on PE74 with chloride substitution on the BDT unit showed increasing photovoltaic performance.In addition,further chlorine substitution on the IID(PE75)would greatly reduce the non-radiative voltage loss(ΔV3),and the distorted molecular conformation also took responsible for the excessive recombination.As results,PE74:Y6-based device achieves a power conversion efficiency(PCE)of 11.06%with open-circuit voltage(VOC)of 0.76 V,which are higher than those of PE70:Y6(PCE of 10.40%and VOC of 0.72 V)and PE75:Y6-based device(PCE of 6.24%and VOC of 0.84 V).This work demonstrates the regularity of the photovoltaic performance caused by chlorination strategy in polymer in the non-fullerene OSC devices,which provide important insights into highperformance photovoltaic materials.展开更多
Through kinetic method, the reaction mechanism and the rate equations of chlorination of polyethylene are suggested in this paper. The rate of chlorination is second order with respect to the concentration of methylen...Through kinetic method, the reaction mechanism and the rate equations of chlorination of polyethylene are suggested in this paper. The rate of chlorination is second order with respect to the concentration of methylene remained and chlorine, respectively. Apparent changes in crystallinity during chlorination processes were determinated by differential scanning calorimetry(DSC). The mathematical model relating crystallinety with kinetic parameters and function of sequence length distribution are derived.展开更多
A convenient method for the chlorination in allylic position was developed by using the aqueous solution of sodium hypochlorite(2%_5% active chlorine) and an acid as chlorination reagent in a diphase system. The metho...A convenient method for the chlorination in allylic position was developed by using the aqueous solution of sodium hypochlorite(2%_5% active chlorine) and an acid as chlorination reagent in a diphase system. The method has the advantage of cheap reagents, mild reaction conditions and good yields. The quantity and the feeding rate of the chlorination reagent can be controlled easily. The method is particularly suitable for the chlorination in laboratories.展开更多
Objective To investigate the reduction of chlorination by-products (CBPs) precursors using the fluidized-bed biofdm reactor (FBBR). Methods Reduction of total organic carbon (TOC), ultraviolet absorbance (UV254...Objective To investigate the reduction of chlorination by-products (CBPs) precursors using the fluidized-bed biofdm reactor (FBBR). Methods Reduction of total organic carbon (TOC), ultraviolet absorbance (UV254), tfihalomethane (THM) formation potential (THMFP), haloacetic acid (HAA) formation potential (HAAFP), and ammonia in FBBR were evaluated in detail. Results The reduction of TOC or UV254 was low, on average 12.6% and 4.7%, respectively, while the reduction of THMFP and HAAFP was significant. The reduction of ammonia was 30%-40% even below 3℃, however, it could quickly rise to over 50% above 3℃. Conclusions The FBBR effectively reduces CBPs and ammonia in drinking water even at low temperature and seems to be a very promising and competitive drinking water reactor for polluted surface source waters, especially in China.展开更多
Organic halogens generated in the chlorlnatlon treatment of wool are proven to be acutely toxic to human beings. Legislation on environmental pollution has become more and more stringent in recent years. So the chlorl...Organic halogens generated in the chlorlnatlon treatment of wool are proven to be acutely toxic to human beings. Legislation on environmental pollution has become more and more stringent in recent years. So the chlorlnation treatment is faced with disuse. Alkaline hydrolysis is adopted to reduce the AOX (Absorbable Organic Halogen) concentrations in the effluents from the chlorlnatlontreatment under 40℃ and pH values 9, 10, 11 and 12. After treatment the reduction of AOX appears approximately 65%.展开更多
基金financially supported by the National Natural Science Foundation of China (50779078)
文摘Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determining an optimal chlorination scheme are the different responses of crops to the chloride added into the soil through chlorination. During two seasons in 2008 and 2009, field experiments were conducted in a solar-heated greenhouse with drip irrigation systems applying secondary sewage effluent to tomato plants to investigate the influences of chlorine injection intervals and levels on plant growth, yield, fruit quality, and emitter clogging. Injection intervals ranging from 2 to 8 wk and injection concentrations ranging 2-50 mg L-1 of free chlorine residual at the end of the laterals were used. For the 2008 experiments, the yield from the treatments of sewage application with chlorination was 7.5% lower than the yield from the treatment of sewage application without chlorination, while the yields for the treatments with and without chlorination were similar for the 2009 experiments. The statistical tests indicated that neither the chlorine injection intervals and concentrations nor the interactions between the two significantly influenced plant height, leaf area, or tomato yield for both years. The qualities of the fruit in response to chlorination were parameter-dependent. Chlorination did not significantly influence the quality of ascorbic acid, soluble sugar, or soluble acids, but the interaction between the chlorine injection interval and the chlorine concentration significantly influenced the levels of soluble solids. It was also confirmed that chlorination was an effective method for reducing biological clogging. These results suggested that chlorination is safe for a crop that has a moderate sensitivity to chlorine, like tomato, and can maintain a high level of performance in drip irrigation systems applying sewage effluent.
文摘Bormate (BrO3^-) is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions, particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet (UV)/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards (10 μg/L). UV irradiation enhanced the decay of free chlorine, and, simultaneously, 6.6%-32% of Br^- was oxidized to BrO3^-. And the formation of bromate exhibited three stages: rapid stage, slow stage and plateau. Under the experimental conditions (pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L), low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.
基金financially supported by the National Key Basic Research Program of China(No.2014CB643403)the National Science Fund for Distinguished Young Scholars(No.51225401)
文摘The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process,various process parameters were studied,including the roasting temperature,the addition of NH_4 Cl,the roasting time,the leaching time,and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition,95% of Ni,98% of Cu,and 88% of Co were recovered. In addition,the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores.
基金financially supported by the National NaturalScience Foundation of China (No. 51202249)the National High-Tech Research and Development Program of China (No. 2011AA06A104)the Projects in the National Science & Technology Pillar Program during the 12th Five-year Plan Period (No. 2012BAB08B04)
文摘The chlorination-volatilization process has been adopted to make full use of gold-bearing and iron-rich pyrite cinder. However, problems of low recovery rate, pulverization of pellets, and ring formation have been encountered during the industrialization of this process. The effects of various parameters on the volatilization rates of valuable metals and on the compressive strength of roasted pellets were investigated in this paper. The parameters include the CaCl_2 dosage, heating temperature, and holding time. The results show that heating temperature is the most important parameter for the recovery of target metals. More CaCl_2 was needed for the recovery of zinc than for the recovery of gold, silver, and lead. CaCl_2 started to react with sulfides/SO_2/SiO_2 at temperatures below the melting point of CaCl_2 to generate Cl_2/HCl. Gaseous CaCl_2 was formed at higher temperatures and could react with any of the components. The compressive strength of roasted CaCl_2-bearing pellets first decreased slowly with increasing temperature at temperatures lower than 873 K, which could result in the pulverization of pellets during heating. Their compressive strength increased dramatically with increasing temperature at temperatures greater than 1273 K. Certain quantities of CaCl_2 and Fe(Ⅱ) could improve the compressive strength of the roasted pellets; however, the addition of excessive CaCl_2 decreased the compressive strength of pellets.
基金financially supported by the National Natural Science Foundation of China (51773087, 21733005)the Shenzhen Fundamental Research program (JCYJ20160504151731734,JCYJ20170817111214740)the Shenzhen Nobel Prize Scientists Laboratory Project (C17783101)
文摘Bulk heterojunction(BHJ)polymer solar cells(PSCs)are promising candidates for next-generation solar cells.Benefitting from the persistent efforts in material design and synthesis,systematic device engineering and fundamental understanding of the device physics,the power conversion efficiency(PCE)of single PSC has been pushed to surpass 15%,and that of the tandem PSCs is over 17%.Recently,chlorination has drawn much interest and the chlorinated PSCs have been frequently reported in donor-acceptor(D-A)type conjugated polymers.This review summarizes the recent progress of the chlorinated strategy for highly efficient photovoltaic applications.We firstly discuss the chlorination on the acceptor units in D-A type donor polymers,emphasizing the 4 widely used acceptor units with their improved PCE.secondly,the chlorination on the donor units will be discussed,mainly focusing on the chlorination of benzo[1,2-b:4,b]dithiophene(BDT)unit and 2,2-bithiophene unit.Remarkably,the PCE of the chlorinated BDT-based device has been improved to over 14%.Overall,this review discusses the structure-property correlations of these chlorinated polymers in photovoltaic study,which could further provide guidance on the chlorinated strategy and the molecular design for high-performance photovoltaic devices.
基金This project is financially supported by the National Nature Science Foundation of China (No. 59804004) and (No.50274046)
文摘A new process of enriching germanium from coal ash was developed. The processinvolves in mixing the coal ash and ammonium chloride and then roasting the mixture to producegermanium chloride that is then absorbed by dilute hydrochloric acid and hydrolyzed to germaniumoxide. The germanium recovery reached to 80.2% at the optimum condition: mass ratio of NH_4Cl/coalash is 0.15, roasting temperature 400℃ and roasting time 90 min.
基金supported by the Key Subject of Shanghai Municipality (No.S30109)Shanghai Science and Technology Commission (No.10dz1205302)
文摘The resources of refractory gold ores are abundant, and their effective treatment can bring good economic benefits. This paper investigated the kinetics of leaching gold from refractory gold ores by ultrasonic-assisted electro-chlorination. The effects of ultrasound time ratio, initial hydrochloric acid concentration and leaching temperature on the kinetic parameters were discussed. It is found that the leaching ratio goes up with all the factors increasing. The reaction kinetics is controlled by diffusion. When ultrasound improves the diffusion by reducing the diffusion resistance, the activation energy increases to 37.1 kJ/mol.
基金the financial support from the National Natural Science Foundation of China (Grant Nos. 21822503, 51973043, 21534003, 21721002, 51863002 and 51973042)the Ministry of Science and Technology of China (Grant No. 2016YFA0200700)+2 种基金Youth Innovation Promotion AssociationK. C. Wong Education Foundationthe Chinese Academy of Sciences。
文摘Three small-molecule donors based on dithieno [2,3-d:2’,3 ’-d’]-benzo[1,2-b:4,5-b’] dithiophene(DTBDT)unit were designed and synthesized by side chain regulation with chlorinated or/and sulfurated substitutions(namely ZR1,ZR1-Cl,and ZR1-S-Cl respectively),along with a crystalline non-fullerene acceptor IDIC-4 Cl with a chlorinated 1,1-dicyanomethylene-3-indanone(IC) end group.Energy levels,molar extinction coefficients and crystallinities of three donor molecules can be effectively altered by combining chlorination and sulfuration strategies.Especially,the ZR1-S-Cl exhibited the best absorption ability,lowest higher occupied molecular orbital(HOMO) energy level and highest crystallinity among three donors,resulting in the corresponding all-small-molecule organic solar cells to produce a high power conversion efficiency(PCE) of 12.05% with IDIC-4 Cl as an acceptor.
基金Project supported by the Hi-Tech Research and Development Program(863) of China (No. 2003AA601130).
文摘The ion chromatography combined solid phase extraction (SPE) method was developed for the analysis of low concentration haloacetic acids (HAAs), a class of disinfection by-products formed from chlorination of hospital wastewater. The monitored HAAs included monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, dibromoacetic acid and trichloroacetic acid. The method employed a sodium hydroxide eluent at a flow rate of 0.8 ml/min, electrolytically generated gradients, and suppressed conductivity detection. To analyze the HAAs in real hospital wastewater samples, C18 pretreatment cartridge was utilized to reduce samples' turbidity. Preconcentration with SPE and matrix elimination with treatment cartridges were investigated and found to be able to obtain acceptable detection limits. Linearity, repeatability and detection limits of the above method were evaluated. The detection limits of monobromoacetic acid and dibromoacetic acid were 2.61 μg/L and 1.30 μg/L, respectively, and the other three acids are ranging from 0.48 to 0.82μg/L under 25-fold preconcentration. When the above optimization procedure was applied to three hospital wastewater samples with different treatment processes in Tianjin, it was found that the dichloroacetic acid was the major compound, and the growth ratios of the HAAs after disinfection by sodium hypochlorite were 91.28%, 63.61% and 79.50%, respectively.
文摘The present paper reports the effective utilization of marble sludge powder(MSP)for the recovery of potash values from waste mica scrap using chlorination roasting-water leaching method.Characterization studies indicated the presence of dolomite as the major mineral phase in MSP,whereas muscovite and quartz were observed in the mica sample.The acid leaching studies suggest a maximum of 22%potash recovery under conditions:4 M H2SO4 acid,particle size of^100μm,stirring speed of 600 r/min,leaching temperature of 75℃,and leaching time of 90 min.The chlorination roasting-water leaching process was adopted to achieve the lowest level of 80%-90%potash recovery.The optimum conditions for the recovery of^93%potash from mica(~8.6wt%K2O)requires 900℃ roasting temperature,30 min roasting time,and 1:1:0.75 mass ratio of mica:MSP:NaCl.The roasting temperature and amount of NaCl are found to be the most important factors for the recovery process.The reaction mechanism suggests the formation of different mineral phases,including sylvite(KCl),wollastonite,kyanite,and enstatite,during roasting,which were confirmed by X-ray diffraction(XRD)analyses and scanning electron microscopy(SEM)morphologies.The MSP-blended NaCl additive is more effective for potash recovery compared with the other reported commercial roasting additives.
基金This work was part of a project (No. 50708050)supported by the National Natural Science Foundation of China.
文摘Objective To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.
文摘Haloacetic acids(HAAs) are formed during the chlorination of drinking water,which are harmful to people′s health due to their carcinogenic and mutagenic effects. In the present study,a detection method combining methyl tert -butyl ether(MtBE) extraction with acid catalysis and gas chromatography coupled with an electron capture detector(GC/ECD) was developed for determining HAAs. The detection limit of this method(MDL) and relative standard deviation(RSD) were below 0.37 μg/L and 6.2%,respectively. The laboratory chlorination experiments were conducted with the purpose of investigating the influences of reaction time,temperature,UV_ 254 ,bromide and ammonia-nitrogen on the formation of HAAs. The results show that the formation amount of HAAs increases with increasing reaction time and temperature,respectively;and there exists a linear relationship between the formation of HAAs and UV_ 254 . The formation amount of HAAs decreases first and then increases as the bromide ion concentration increases,and adding NH +_4 is a possible way to control the formation of HAAs.
基金financially supported by the National Natural Science Foundation of China(50779078 and 50909101)
文摘Chlorination is usually an economical method for treating clogging in drip emitters during sewage application. Appropriate assessment of the responses of soil and crop is essential for determining an optimal chlorination scheme. During 2008 to 2009, field experiments were conducted in a solar-heated greenhouse for tomato drip irrigated with secondary sewage effluent, to investigate the influences of chlorine injection intervals and levels on soil chemical properties and nitrogen uptake. Injection intervals ranging from two to eight weeks and injection concentrations ranging from 2 to 50 mg L-1 were used. A salinity factor and a nutrient factor were extracted from the pool of the nine soil chemical constituents using factor analysis method. The results demonstrated that chlorination practices increased the residual Cl in the soil, resulting in an increased salinity factor, especially for the frequent chlorination at a high injection concentration. Chlorination weakened the accumulation of nutrients factor in the upper soil layer. Nitrogen uptake of the tomato plants also was inhibited by the increased salinity in the upper soil layer caused by high chlorination levels. In order to reduce the unfavorable effect on soil chemical properties and nitrogen uptake, chlorination scheme with concentrations of lower than 20 mg L-1 was recommended.
文摘The use of seawater for industrial cooling is a vital technology that poses some of the most profound environmental impact on the water quality in the Arabian Gulf. Biocide (chlorine) is added to the seawater to control biofouling of the cooling system. This added chlorine reacts with bromide and other chemicals naturally exist in the water to form a wide range of oxidants. Regrettably, reactions between the residual oxidants and natural organic matter in the water lead to formation of toxic halogenated organic compounds that have detrimental effects on the environment when they are discharged into the Gulf. This paper describes the formation of trihalomethanes (THMs) in seawater cooling systems. Results of kinetic experiments have shown that concentrations of THMs increased rapidly with time during the first half hour. Chlorination of seawater has shown significant increase in total THMs (TTHMs) and in bromoform concentrations. Rapid decrease of UV absorbance at 254 nm was also observed during seawater chlorination which is indicative of natural organic matter degradation into small organic molecules including THMs and other by-products. The increase in chlorine dose was accompanied with an increase in TTHMs and bromoform concentrations. Linear relationships between total chlorine concentration and both final TTHMs and bromoform concentrations were established. First order exponential decay and exponential associate functions were developed to correlate chlorine dose with formed THMs.
文摘For a chlorinating method at low temperature, the possibility of chlorination of Nd2O3 by a mechanochemical reaction with CCl4 was studied using a planetary ball mill. The mechanochemical experiments were conducted by changing the pot materials, milling time, molar ratio of CCl4/Nd2O3, and revolution speed. As the results of obtained products by X-ray diffractometry and Raman spectroscopy, it was confirmed that the chlorination to NdOCl from Nd2O3 with CCl4 was advanced at room temperature in a zirconia or tungsten pot with balls. We found that an extension of the milling time and an increase of the number of ball were effective to the chlorination to NdOCl and that tensile stress remained in the milled powder by using a planetary ball mill.
基金the National Key Research and Development Program of China(2017YFA0206600)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDB-SSW-SLH033)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB36000000)the National Natural Science Foundation of China(NSFC,Nos.21875052,51873044,52073067).
文摘Isoindigo(IID)has been widely used as strong acceptor unit(A)to construct narrow bandgap polymers in organic field effect transistors(OFETs)and organic solar cells(OSCs).Combing with IID,we chose benzodithiophene(BDT)as the donor unit(D)and thieno[3,2-b]thiophene(TT)as theπbridge to construct a new type of D-π-A polymer PE70.Based on PE70,we adopt the chlorination strategy to fine-tune photoelectric characteristics and film morphology,and then developed PE74 and PE75.By blending with non-fullerene acceptor(NFA)Y6,device based on PE74 with chloride substitution on the BDT unit showed increasing photovoltaic performance.In addition,further chlorine substitution on the IID(PE75)would greatly reduce the non-radiative voltage loss(ΔV3),and the distorted molecular conformation also took responsible for the excessive recombination.As results,PE74:Y6-based device achieves a power conversion efficiency(PCE)of 11.06%with open-circuit voltage(VOC)of 0.76 V,which are higher than those of PE70:Y6(PCE of 10.40%and VOC of 0.72 V)and PE75:Y6-based device(PCE of 6.24%and VOC of 0.84 V).This work demonstrates the regularity of the photovoltaic performance caused by chlorination strategy in polymer in the non-fullerene OSC devices,which provide important insights into highperformance photovoltaic materials.
文摘Through kinetic method, the reaction mechanism and the rate equations of chlorination of polyethylene are suggested in this paper. The rate of chlorination is second order with respect to the concentration of methylene remained and chlorine, respectively. Apparent changes in crystallinity during chlorination processes were determinated by differential scanning calorimetry(DSC). The mathematical model relating crystallinety with kinetic parameters and function of sequence length distribution are derived.
文摘A convenient method for the chlorination in allylic position was developed by using the aqueous solution of sodium hypochlorite(2%_5% active chlorine) and an acid as chlorination reagent in a diphase system. The method has the advantage of cheap reagents, mild reaction conditions and good yields. The quantity and the feeding rate of the chlorination reagent can be controlled easily. The method is particularly suitable for the chlorination in laboratories.
基金This work was supported by National Natural Science Foundation of China (No. 50408006).
文摘Objective To investigate the reduction of chlorination by-products (CBPs) precursors using the fluidized-bed biofdm reactor (FBBR). Methods Reduction of total organic carbon (TOC), ultraviolet absorbance (UV254), tfihalomethane (THM) formation potential (THMFP), haloacetic acid (HAA) formation potential (HAAFP), and ammonia in FBBR were evaluated in detail. Results The reduction of TOC or UV254 was low, on average 12.6% and 4.7%, respectively, while the reduction of THMFP and HAAFP was significant. The reduction of ammonia was 30%-40% even below 3℃, however, it could quickly rise to over 50% above 3℃. Conclusions The FBBR effectively reduces CBPs and ammonia in drinking water even at low temperature and seems to be a very promising and competitive drinking water reactor for polluted surface source waters, especially in China.
文摘Organic halogens generated in the chlorlnatlon treatment of wool are proven to be acutely toxic to human beings. Legislation on environmental pollution has become more and more stringent in recent years. So the chlorlnation treatment is faced with disuse. Alkaline hydrolysis is adopted to reduce the AOX (Absorbable Organic Halogen) concentrations in the effluents from the chlorlnatlontreatment under 40℃ and pH values 9, 10, 11 and 12. After treatment the reduction of AOX appears approximately 65%.