Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province...Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province.The results show that soils near sewer outlet,sewer channel and in control area are averaged 2 239.5,995.33 and 104.9 mg/kg,respectively.The total Cr has a relative accumulation in soil depth of 200-400 mm near the sewer outlet,mainly enriches in the surface layer（0-200 mm） near the sewer channel and decreases gradually in unpolluted soils.The differential concentration level of enrichment between layers is little.The results also indicate that the three vegetables of celery,lettuce and Chinese cabbage are able to convert the potentially toxic Cr（Ⅵ） species into the non-toxic Cr（Ⅲ） species,and the chromium contents in the edible parts of the vegetables are averaged 11.95 mg/kg.The transfer factors of the three vegetables follow the order：Chinese cabbage lettuce celery.The estimated total daily intake of chromium substantially exceeds the dietary allowable value,which may pose health risks to local population.展开更多
Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic ...Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr（VI）,Cr（III）,Pb（II） and Cd（II） by algal biomass obtained from algae Sargassum wightii（brown） and Caulerpa racemosa（green）.Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr（VI）,Cr（III）,Pb（II） and Cd（II） ions.C.racemosa exhibited 85% biosorption of Cd（II） and Cr（VI）,and 50% biosorption of Cr（III） and Pb（II）.The results of our study suggest that seaweed biomass can be used efficiently for展开更多
Water samples from chromite mine quarry of Sukinda and its adjacent areas were analyzed for their heavy metal contamination along with physico-chemical and microbial contents. The chromite mine water samples possessed...Water samples from chromite mine quarry of Sukinda and its adjacent areas were analyzed for their heavy metal contamination along with physico-chemical and microbial contents. The chromite mine water samples possessed high concentrations of heavy metals in the order of Cr〉Fe〉Zn〉Ni〉Co〉Mn while ground water did not show any heavy metal contamination except Fe. Physico-chemical parameters of mine water samples showed deviation from those of normal water. Mine water harboured low microbial populations of bacteria, fungi and actinomycetes in comparison with mine adjacent water samples. The correlation of data between metals with physico-chemical parameters showed both positive and negative responses while that of metal and microbial population exhibited negative correlation. Bacterial strains isolated from chromite mine water exhibited high tolerance towards chromium and other heavy metals as well as antibiotics which could be used as an indicator of heavy metal pollution.展开更多
FeCrAl(f)/HA biological functionally gradient materials(FGMs) were successfully fabricated by the hot pressing technique.Scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and bending strength test ...FeCrAl(f)/HA biological functionally gradient materials(FGMs) were successfully fabricated by the hot pressing technique.Scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and bending strength test machine were utilized to characterize the microstructure,component,mechanical properties and the formation of the Ca-deficient apatite on the surface of these materials.The results indicate that an asymmetrical FeCrAl(f)/HA FGM,consolidating powders prepared by mixing HA with 3%–15%(volume fraction) is successfully prepared.Both of the matrix and FeCrAl fiber are integrated very tightly and bite into each other very deeply.And counter diffusion takes place to some extent in two phase interfaces.The elemental compositions of the FeCrAl(f)/HA FGM change progressively.Ca and P contents increase gradually with immersion time increasing,and thereafter approach equilibrium.The bone-like apatite layer forms on the materials surface,which possesses benign bioactivity,and the favorable biocompatibility can provide potential firm fixation between FeCrAl(f)/HA asymmetrical FGM implants and human bone.展开更多
The effectiveness of vitamin C in treating Cr(VI)-contaminated water is being evaluated. Cr(VI) is an identified pollutant of some soils and groundwater. Vitamin C, an important biological reductant in humans and anim...The effectiveness of vitamin C in treating Cr(VI)-contaminated water is being evaluated. Cr(VI) is an identified pollutant of some soils and groundwater. Vitamin C, an important biological reductant in humans and animals, can be used to transform Cr(VI) to essentially nontoxic Cr(III). The removal efficiency was 89% when the mass concentration of vitamin C was 80 mg/L in 60 min, and nearly 100% Cr(VI) was removed when the mass concentration was 100 mg/L. Our data demonstrated that the removal efficiency was affected by vitamin C concentration, the reaction temperature and the dissolved oxygen concentration. The reaction mechanism of Cr(VI) by vitamin C was presented. Our study opens the way to use vitamin C to remediate Cr(VI)-contaminated soils and groundwater.展开更多
A batch experiment was conducted to investigate the adsorption of trivalent chromium （Cr（Ⅲ）） from aqueous solutions by sugarcane pulp residue （SPR） and biochar. The results show that Cr（Ⅲ） adsorption by SPR ...A batch experiment was conducted to investigate the adsorption of trivalent chromium （Cr（Ⅲ）） from aqueous solutions by sugarcane pulp residue （SPR） and biochar. The results show that Cr（Ⅲ） adsorption by SPR and biochar is highly pH-dependent and Cr（Ⅲ） adsorption amount increases with the increase of pH. The adsorption kinetics of Cr（Ⅲ） fits well with the pseudo-second-order model. The maximum Cr（Ⅲ） adsorption capacities of 15.85 mg/g and 3.43 mg/g for biochar and SPR were calculated by Langmuir model. This indicates that biochar has a larger ability for Cr（Ⅲ） adsorption than SPR. The free energy change value （AG） reveals a spontaneous sorption process of Cr（Ⅲ） onto SPR and non-spontaneous sorption process onto biochar. The entropy change （AS） and enthalpy change （AH） are found to be 66.27 J/（mol＇K） and 17.13 kJ/mol for SPR and 91.59 J/（mol-K） and 30.875 kJ/mol for biochar which further reflect an affinity of Cr（Ⅲ） onto SPR and biochar. It is suggested that biochar has potential to be an efficient adsorbent in the removal of Cr（Ⅲ） from industrial wastewater.展开更多
A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Or3+, and the relevant purifying mechanism was also addressed. ...A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Or3+, and the relevant purifying mechanism was also addressed. In detail, organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes. However, for heavy metal ions (Cu2+, Cr3+), part was removed by electrodeposition, and some was adsorbed on biofilm. In order to compare with the combined process of micro electrolysis and biofilm, the experimental data of micro electrolysis process (intermittent) or biofilm process (continuous) were provided, and the kinetic data of C6H12O6 (glucose) biodegradation by cultured microbes or acclimated microbes were also obtained. These experimental results indicated that for wastewater initially consisted of CeH12O6 (500mg-L-1), Cu2+ and Cr3+ (10mg-L-1), after treatment, its concentrations of C6H12O6, Cu2+ and Cr3+ were lowered to the level of 55-65mg.L^1, and less than 1mg-L-1, respectively. And the industrial reused water standards could be met by treated wastewater.展开更多
The biosorption mechanism of Cr （Ⅳ） ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetic...The biosorption mechanism of Cr （Ⅳ） ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetics study shows that the adsorption process of Cr （Ⅳ） consists of a very fast stage in the first several minutes, in which more than half of the saturation adsorption is attained, and a slower stage that approximately follows the first order kinetic model, basically Freundlich isotherm models were observed. Comparative studies of FT-LR spectra of K2Cr2O7, free cells of Synechococcus sp., and Cr-bound cells of Synechococcus sp show that the speciation of chromium that binds to the cells ofSynechococcus sp. is Cr （Ⅲ）, instead of Cr （Ⅳ）, and the carboxylic, alcoholic, amido and amino groups may be involved in the binding of Cr （Ⅲ）. Integrative analyses of the surface electric potential, the effect of pH value on adsorption behavior of Cr （Ⅵ）, and the results of FT-IR show that the biosorption of Cr （Ⅵ） follows two subsequent steps, biosorption of Cr2O7 ^2- by electrostatical force at the protonated active sites and reduction of Cr2O7^2- to Cr^3＋ by the reductive groups on the surface of the biosorbents.展开更多
基金Project (2009ZX07212-001-01) supported by the Key Project of National Natural Science Foundation for Water Pollution Control and RemediationProject (50925417) supported by the National Funds for Distinguished Young Scientists+1 种基金Project (50830301) supported by the National Natural Science Foundation of ChinaProject (51074191) supported by the National Natural Science Foundation of China
文摘Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province.The results show that soils near sewer outlet,sewer channel and in control area are averaged 2 239.5,995.33 and 104.9 mg/kg,respectively.The total Cr has a relative accumulation in soil depth of 200-400 mm near the sewer outlet,mainly enriches in the surface layer（0-200 mm） near the sewer channel and decreases gradually in unpolluted soils.The differential concentration level of enrichment between layers is little.The results also indicate that the three vegetables of celery,lettuce and Chinese cabbage are able to convert the potentially toxic Cr（Ⅵ） species into the non-toxic Cr（Ⅲ） species,and the chromium contents in the edible parts of the vegetables are averaged 11.95 mg/kg.The transfer factors of the three vegetables follow the order：Chinese cabbage lettuce celery.The estimated total daily intake of chromium substantially exceeds the dietary allowable value,which may pose health risks to local population.
文摘Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr（VI）,Cr（III）,Pb（II） and Cd（II） by algal biomass obtained from algae Sargassum wightii（brown） and Caulerpa racemosa（green）.Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr（VI）,Cr（III）,Pb（II） and Cd（II） ions.C.racemosa exhibited 85% biosorption of Cd（II） and Cr（VI）,and 50% biosorption of Cr（III） and Pb（II）.The results of our study suggest that seaweed biomass can be used efficiently for
基金Financial support of the UGC-DAE, Center for Scientific Research, Kolkata Centre
文摘Water samples from chromite mine quarry of Sukinda and its adjacent areas were analyzed for their heavy metal contamination along with physico-chemical and microbial contents. The chromite mine water samples possessed high concentrations of heavy metals in the order of Cr〉Fe〉Zn〉Ni〉Co〉Mn while ground water did not show any heavy metal contamination except Fe. Physico-chemical parameters of mine water samples showed deviation from those of normal water. Mine water harboured low microbial populations of bacteria, fungi and actinomycetes in comparison with mine adjacent water samples. The correlation of data between metals with physico-chemical parameters showed both positive and negative responses while that of metal and microbial population exhibited negative correlation. Bacterial strains isolated from chromite mine water exhibited high tolerance towards chromium and other heavy metals as well as antibiotics which could be used as an indicator of heavy metal pollution.
基金Project(51274247)supported by the National Natural Science Foundation of ChinaProject(2012BAE06B00)supported by the National High Technology Research and Development Program to China+1 种基金Project(2011QNZT046)supported by the Fundamental Research Funds of Central South Universities of ChinaProject supported by Hunan Postdoctoral Scientific Program,China
文摘FeCrAl(f)/HA biological functionally gradient materials(FGMs) were successfully fabricated by the hot pressing technique.Scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and bending strength test machine were utilized to characterize the microstructure,component,mechanical properties and the formation of the Ca-deficient apatite on the surface of these materials.The results indicate that an asymmetrical FeCrAl(f)/HA FGM,consolidating powders prepared by mixing HA with 3%–15%(volume fraction) is successfully prepared.Both of the matrix and FeCrAl fiber are integrated very tightly and bite into each other very deeply.And counter diffusion takes place to some extent in two phase interfaces.The elemental compositions of the FeCrAl(f)/HA FGM change progressively.Ca and P contents increase gradually with immersion time increasing,and thereafter approach equilibrium.The bone-like apatite layer forms on the materials surface,which possesses benign bioactivity,and the favorable biocompatibility can provide potential firm fixation between FeCrAl(f)/HA asymmetrical FGM implants and human bone.
基金Project (No. 20407015) supported by the National Natural ScienceFoundation of China
文摘The effectiveness of vitamin C in treating Cr(VI)-contaminated water is being evaluated. Cr(VI) is an identified pollutant of some soils and groundwater. Vitamin C, an important biological reductant in humans and animals, can be used to transform Cr(VI) to essentially nontoxic Cr(III). The removal efficiency was 89% when the mass concentration of vitamin C was 80 mg/L in 60 min, and nearly 100% Cr(VI) was removed when the mass concentration was 100 mg/L. Our data demonstrated that the removal efficiency was affected by vitamin C concentration, the reaction temperature and the dissolved oxygen concentration. The reaction mechanism of Cr(VI) by vitamin C was presented. Our study opens the way to use vitamin C to remediate Cr(VI)-contaminated soils and groundwater.
基金Project(50925417) supported by the National Funds for Distinguished Young Scientist,ChinaProject(50830301) supported by the Key Program of National Natural Science Foundation of ChinaProject(51074191) supported by the National Natural Science Foundation of China
文摘A batch experiment was conducted to investigate the adsorption of trivalent chromium （Cr（Ⅲ）） from aqueous solutions by sugarcane pulp residue （SPR） and biochar. The results show that Cr（Ⅲ） adsorption by SPR and biochar is highly pH-dependent and Cr（Ⅲ） adsorption amount increases with the increase of pH. The adsorption kinetics of Cr（Ⅲ） fits well with the pseudo-second-order model. The maximum Cr（Ⅲ） adsorption capacities of 15.85 mg/g and 3.43 mg/g for biochar and SPR were calculated by Langmuir model. This indicates that biochar has a larger ability for Cr（Ⅲ） adsorption than SPR. The free energy change value （AG） reveals a spontaneous sorption process of Cr（Ⅲ） onto SPR and non-spontaneous sorption process onto biochar. The entropy change （AS） and enthalpy change （AH） are found to be 66.27 J/（mol＇K） and 17.13 kJ/mol for SPR and 91.59 J/（mol-K） and 30.875 kJ/mol for biochar which further reflect an affinity of Cr（Ⅲ） onto SPR and biochar. It is suggested that biochar has potential to be an efficient adsorbent in the removal of Cr（Ⅲ） from industrial wastewater.
基金Supported by the Natural Science Foundation of Tianjin,China(No.013802911).
文摘A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Or3+, and the relevant purifying mechanism was also addressed. In detail, organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes. However, for heavy metal ions (Cu2+, Cr3+), part was removed by electrodeposition, and some was adsorbed on biofilm. In order to compare with the combined process of micro electrolysis and biofilm, the experimental data of micro electrolysis process (intermittent) or biofilm process (continuous) were provided, and the kinetic data of C6H12O6 (glucose) biodegradation by cultured microbes or acclimated microbes were also obtained. These experimental results indicated that for wastewater initially consisted of CeH12O6 (500mg-L-1), Cu2+ and Cr3+ (10mg-L-1), after treatment, its concentrations of C6H12O6, Cu2+ and Cr3+ were lowered to the level of 55-65mg.L^1, and less than 1mg-L-1, respectively. And the industrial reused water standards could be met by treated wastewater.
基金Project(50321402) supported by the National Natural Science Foundation of China
文摘The biosorption mechanism of Cr （Ⅳ） ions on Synechococcus sp. biosorbent was studied by analyzing the biosorption kinetics as well as speciation change and bond formation during the biosorption process. The kinetics study shows that the adsorption process of Cr （Ⅳ） consists of a very fast stage in the first several minutes, in which more than half of the saturation adsorption is attained, and a slower stage that approximately follows the first order kinetic model, basically Freundlich isotherm models were observed. Comparative studies of FT-LR spectra of K2Cr2O7, free cells of Synechococcus sp., and Cr-bound cells of Synechococcus sp show that the speciation of chromium that binds to the cells ofSynechococcus sp. is Cr （Ⅲ）, instead of Cr （Ⅳ）, and the carboxylic, alcoholic, amido and amino groups may be involved in the binding of Cr （Ⅲ）. Integrative analyses of the surface electric potential, the effect of pH value on adsorption behavior of Cr （Ⅵ）, and the results of FT-IR show that the biosorption of Cr （Ⅵ） follows two subsequent steps, biosorption of Cr2O7 ^2- by electrostatical force at the protonated active sites and reduction of Cr2O7^2- to Cr^3＋ by the reductive groups on the surface of the biosorbents.
