Artificial neural network（ANN） and full factorial design assisted atrazine（AT） multiple regression adsorption model（AT-MRAM） were developed to analyze the adsorption capability of the main components in the surf...Artificial neural network（ANN） and full factorial design assisted atrazine（AT） multiple regression adsorption model（AT-MRAM） were developed to analyze the adsorption capability of the main components in the surficial sediments（SSs）. Artificial neural network was used to build a model（the determination coefficient square r2 is 0.9977） to describe the process of atrazine adsorption onto SSs, and then to predict responses of the full factorial design. Based on the results of the full factorial design, the interactions of the main components in SSs on AT adsorption were investigated through the analysis of variance（ANOVA）, F-test and t-test. The adsorption capability of the main components in SSs for AT was calculated via a multiple regression adsorption model（MRAM）. The results show that the greatest contribution to the adsorption of AT on a molar basis was attributed to Fe/Mn（–1.993 μmol/mol）. Organic materials（OMs） and Fe oxides in SSs are the important adsorption sites for AT, and the adsorption capabilities are 1.944 and 0.418 μmol/mol, respectively. The interaction among the non-residual components（Fe, Mn oxides and OMs） in SSs interferes in the adsorption of AT that shouldn’t be neglected, revealing the significant contribution of the interaction among non-residual components to controlling the behavior of AT in aquatic environments.展开更多
Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation...Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II)and Mn(II)by Pseudomonas taiwanensis(marked as P4)and Pseudomonas plecoglossicida(marked as G1)contains rich reactive oxygen functional groups,which play critical roles in the removal efficiency and immobilization of heavymetal(loid)s in co-contamination system.The isolated strains P4 and G1 can growwell in the following environments:pH 5-9,NaCl 0-4%,and temperature 20-30℃.The removal efficiencies of Fe,Pb,As,Zn,Cd,Cu,and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system(the initial concentrations of heavy metal(loid)were 1 mg/L),approximately reaching 96%,92%,85%,67%,70%,54%and 15%,respectively.The exchangeable and carbonate bound As,Cd,Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil,thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s.This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.展开更多
Bisphenol A(BPA)is a pervasive endocrine disruptor that enters the environment through anthropogenic activities,posing significant risks to ecosystems and human health.Advanced oxidation processes(AOPs)are promising m...Bisphenol A(BPA)is a pervasive endocrine disruptor that enters the environment through anthropogenic activities,posing significant risks to ecosystems and human health.Advanced oxidation processes(AOPs)are promising methods for the removal of organic microcontaminants in the environment.Biogenic manganese oxides(BMO)are reported as catalysts due to their transitionmetal nature,and are also readily generated bymanganeseoxidizing microorganisms in the natural environment,and therefore their roles and effects in AOPs-based environmental remediation should be investigated.However,biogenic ironmanganese oxides(BFMO)are actually generated rather than BMO due to the coexistence of ferrous ionswhich can be oxidized to iron oxides.Therefore,this study produced BFMO originating from a highly efficientmanganese-oxidizing fungus Cladosporium sp.XM01 and chose peroxymonosulfate(PMS)as a typical oxidant for the degradation of bisphenol A(BPA),a model organic micropollutant.Characterization results indicate that the formed BFMO was amorphouswith a lowcrystallinity.The BFMO/PMS system achieved a high degradation performance that 85%BPA was rapidly degraded within 60min,and therefore the contribution of BFMO cannot be ignored during PMS-based environmental remediation.Different from the findings of previous studies(mostly radicals and singlet oxygen),the degradationmechanism was first proven as a 100%electron-transfer pathway mediated by high-valence Mn under acidic conditions provided by PMS.The findings of this study provide new insights into the degradation mechanisms of pollutants using biogenic metal oxides in PMS activation and the contribution of their coexistence in AOPs-based environmental remediation.展开更多
Antimony（Sb）, which can be toxic at relatively low concentrations, may co-exist with Mn（Ⅱ）and/or Fe（Ⅱ） in some groundwater and surface water bodies. Here we investigated the potential oxidation and adsorption ...Antimony（Sb）, which can be toxic at relatively low concentrations, may co-exist with Mn（Ⅱ）and/or Fe（Ⅱ） in some groundwater and surface water bodies. Here we investigated the potential oxidation and adsorption pathways of Sb（Ⅲ and V） species in the presence of Mn（Ⅱ） and Mn-oxidizing bacteria, with or without Fe（Ⅱ）. Batch experiments were conducted to determine the oxidation and adsorption characteristics of Sb species in the presence of biogenic Mn oxides（BMOs）, which were formed in-situ via the oxidation of Mn（Ⅱ） by a Mn-oxidizing bacterium（Pseudomonas sp. QJX-1）. Results indicated that Sb（Ⅲ） ions could be oxidized to Sb（V） ions by BMO, but only Sb（V） originating from Sb（Ⅲ） oxidation was adsorbed effectively by BMO. Introduced Fe（Ⅱ） was chemically oxidized to Fe OOH, the precipitates of which mixed with BMO to form a new compound, biogenic Fe–Mn oxides（BFMO）. The BMO part of the BFMO mainly oxidized and the Fe OOH of the BFMO mainly adsorbed the Sb species. In aquatic solutions containing both As（Ⅲ） and Sb（Ⅲ）, the BFMO that formed in-situ preferentially oxidized Sb over As but adsorbed As more efficiently. Chemical analysis and reverse transcription real-time polymerase chain reaction revealed that the presence of Fe（Ⅱ）, As（Ⅲ） and Sb（Ⅲ） accelerated the oxidation of Mn（Ⅱ） but inhibited the activity of Mn-oxidizing bacteria. These results provide significant insights into the biogeochemical pathways of Sb, Mn（Ⅱ） in aquatic ecosystems, with or without Fe（Ⅱ）.展开更多
Cadmium (Cd) and arsenic (As) are two of the most toxic elements.However,the chemical behaviors of these two elements are different,making it challenging to utilize a single adsorbent with high adsorption capacity for...Cadmium (Cd) and arsenic (As) are two of the most toxic elements.However,the chemical behaviors of these two elements are different,making it challenging to utilize a single adsorbent with high adsorption capacity for both Cd(Ⅱ) and As(Ⅴ) removal.To solve this problem,we synthesized HA/Fe-Mn oxides-loaded biochar (HFMB),a novel ternary material,to perform this task,wherein scanning electron microscopy (SEM) combined with EDS (SEM-EDS) was used to characterize its morphological and physicochemical properties.The maximum adsorption capacity of HFMB was 67.11 mg/g for Cd(Ⅱ) and 35.59 mg/g for As(Ⅴ),which is much higher compared to pristine biochar (11.06 mg/g,0 mg/g for Cd(Ⅱ) and As(Ⅴ),respectively).The adsorption characteristics were investigated by adsorption kinetics and the effects of the ionic strength and pH of solutions.X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) revealed that chelation and deposition were the adsorption mechanisms that bound Cd(Ⅱ) to HFMB,while ligand exchange was the adsorption mechanism that bound As(Ⅴ).展开更多
Anaerobic digestion(AD),as an eco-friendly biological process,shows potential for the decomposition of leachate produced by waste incineration power plants.In this study,the effects of Fe oxides nano-modified pumice(F...Anaerobic digestion(AD),as an eco-friendly biological process,shows potential for the decomposition of leachate produced by waste incineration power plants.In this study,the effects of Fe oxides nano-modified pumice(FNP)were investigated on the fresh leachate AD process.Firstly,a simple hydrothermal method was used to prepare FNP,then introduced into the UASB reactor to evaluate its AD efficiency.Results showed that the inclusion of FNP could shorten the lag phase by 10 days compared to the control group.Furthermore,cumulative methane production in the FNP group was enhanced by 20.11%.Mechanistic studies suggested that hydrogenotrophic methanogenesis in the FNP group was more pronounced due to the influence of key enzymes(i.e.,dehydrogenase and coenzyme F420).Microbial community analysis demonstrated that FNP could enhance the abundance of Methanosarcina,Proteobacteria,Sytrophomonas,and Limnobacter,which might elevate enzyme activity involved in methane production.These findings suggest that FNP might mediate interspecies electron transfer among these microorganisms,which is essential for efficient leachate treatment.展开更多
The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. ...The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. The molar ratio of Fe and Mn in the synthetic Fe-Mn binary oxides was 4 ： 3. The FM-1 and FM-2（prepared at different activation temperatures） having high specific surface areas（358.87 and 128.58 m^2/g, respectively） were amorphous and of nano particle types. The amount of arsenic adsorbed on FM-1 was higher than that adsorbed on FM-2 particles. After adsorption by FM-1, residual arsenic concentration decreased to less than 10 μg/L. The adsorption kinetics data were analyzed using different kinetic models including pseudo first-order model, pseudo second-order model, Elovich model and intraparticle diffusion model. Pseudo second-order kinetic model was the most appropriate model to describe the adsorption kinetics. The adsorption percentage of As（Ⅲ） increased in the p H range of 2–3 while it decreased with the increase of pH（ 3〈pH〈10）. The effects of coexisting anions on As（Ⅲ） removal using FM-1 and FM-2 were also studied and the order of the effects is as follows： NO_3^-, Cl-, F-〈SO_4^（2-）, HCO_3-〈H_2PO_4^-, indicating that H_2PO_4^- is the major competitor with As（Ⅲ） for adsorptive sites on the surface of the adsorbents. The higher adsorption capacity of FM-1 makes it potentially attractive adsorbent for the removal of As（Ⅲ） from groundwater.展开更多
A series of Mn-Cu mixed oxide catalysts were prepared by precipitation method. The catalysts were characterized by N2 adsorp- tion-desorption, H2-TPR and XPS. When the loading ratio of manganese oxides to copper oxide...A series of Mn-Cu mixed oxide catalysts were prepared by precipitation method. The catalysts were characterized by N2 adsorp- tion-desorption, H2-TPR and XPS. When the loading ratio of manganese oxides to copper oxides was 8：2 or 7：3, the catalysts possessed better catalytic activity, and benzene was converted completely at 558 K. Results of H2-TPR showed that the loading of a small amount of copper oxides decreased the reduction temperature of catalysts. Results of XPS showed that the loading of a small amount of copper oxides increased the proportion of manganese and defective oxygen on the surface of catalysts, and stabilized manganese at higher oxidation state. And the catalyst with the loading ratio 7：3 was a little worse than 8：2, since the interaction between manganese oxides and copper oxides is too strong, copper oxides migrate to the surface of catalysts and manganese oxides in excess are immerged.展开更多
Utilizing Si, Fe and Mn concentrations within the end-member PACMANUS hydrothermal fluid, Si-Fe-Mn-H2O Pourbaix diagrams were constructed at 300℃and 25℃. ThePourbaix diagrams show that the main Si, Fe and Mn oxides ...Utilizing Si, Fe and Mn concentrations within the end-member PACMANUS hydrothermal fluid, Si-Fe-Mn-H2O Pourbaix diagrams were constructed at 300℃and 25℃. ThePourbaix diagrams show that the main Si, Fe and Mn oxides species precipitating from the hydrothermal fluid were SiO2, Fe（OH）3, Fe3（OH）8, Mn3O4, and Mn2O3at 25℃. During mixing of hydrothermal fluid with seawater, SiO2 precipitated earlier than Fe-Mn-oxyhydroxides because of the lower stability boundary. Then Fe（OH）2 precipitated first, followed by Fe3（OH）8 and Fe（OH）3, and last, small amounts of Mn3O4 and Mn2O3 precipitated. Fe（OH）3was readily de-posited in alkaline solution with little influence by Eh. There were many Si-Fe-Mn-concentric particles in the polished sections of the massive precipitates collected from PACMANUS. In the concentric nucleus and ellipsoid, Si oxides precipitated first before the hydrothermal fluid had mixed with seawater. In the concen-tric nucleus, after the precipitation of Si oxides, the increase of pH and Eh promoted the precipitation of Mn oxides around the Si oxides. In the large ellipsoid, the precipitation of Fe was divided into two periods. In the early period, increase of pH value of hydrothermal fluid produced by low-temperature convection and an input of a small volume of seawater promoted a small amount of Fe（OH）3 to precipitate in the Si-rich core. In the late period, after complete mixing with seawater and the resultant fluid was close to neutral or slightly alkaline in pH, Fe（OH）3was easily precipitated from the solution and distributed around the Si-rich core.展开更多
Si-Fe-Mn-oxyhydroxides dredged at the PACMANUS （Papua New Guinea-Australia-Canada-Manus） hydrothermal field, Eastern Manus Basin, have 87Sr/SSSr=0.708 079-0.708 581; eNd=5.149 833-6.534 826; 208pb/204pb=38.245-38.44...Si-Fe-Mn-oxyhydroxides dredged at the PACMANUS （Papua New Guinea-Australia-Canada-Manus） hydrothermal field, Eastern Manus Basin, have 87Sr/SSSr=0.708 079-0.708 581; eNd=5.149 833-6.534 826; 208pb/204pb=38.245-38.440; 207pb/204pb=lS.503-15.560; 206pb/204pb=lS.682-18.783. s7sr/sSSr isotope ratios are relatively homogeneous and close to the value of the surrounding seawater （0.709 16）. The content of Sr in the samples contributed by seawater was estimated to be 76.7%-83.1% of total amount. The mixing temperature of hydrothermal fluids and seawater were ranging from 53.2℃ to 72.2℃ and the hydrothermal activities were unstable when the samples precipitated. The eNd values of all the samples are positive, which differ from the values of ferromanganese nodules （crusts） with hydrogenic origin. Nd was mainly derived from substrate rocks leached by hydrothermal circulation and preserved the hydrothermal signature. Ph isotopic compositions of most samples show minor variability except Sample #9-2 that has relatively high values of Pb isotopes. The Pb may be derived from the Eastern Manus Basin rocks leached by the hydrothermal fluid. The slightly lower 28pb/204pb and 207pb/204pb values of the samples indicated that the hydrothermal circulation in PACMANUS was not entire and sufficient, or that hydrothermal circulation had transient changes in the past. Si-Fe-Mn-oxyhydroxides in the samples preserved the heterogeneities of local rocks.展开更多
To reveal the relative contribution of the components, Fe, Mn oxides or organic materials（OMs） in the surficial sediments（SSs）, and the natural surface coating samples（NSCSs） to adsorbing atrazine（AT）, a selec...To reveal the relative contribution of the components, Fe, Mn oxides or organic materials（OMs） in the surficial sediments（SSs）, and the natural surface coating samples（NSCSs） to adsorbing atrazine（AT）, a selective chemical extraction technique was employed, to remove the different components, and the adsorption characteristics of AT on the SSs and the NSCSs were investigated. The observed adsorptions of AT on the original and extracted SSs and NSCSs were analyzed by nonlinear least squares fitting（NLSF） to estimate the relative contribution of the components. The results showed that the maximum adsorption of AT on the NSCSs was greater than that in the SSs, before and after extraction treatments, implying that the NSCSs were more dominant than the SSs for organic pollutant adsorption. It was also found that the Fe oxides, OMs, and residues in SSs（NSCSs） facilitated the adsorption of AT, but Mn oxides directly or indirectly restrained the interaction of AT with SSs（NSCSs） particles. The contribution of the Fe oxides to AT adsorption was more than that of OMs; the greatest contribution to AT adsorption on a molar basis was from the Fe oxides in the nonresidual fractions, indicating that the Fe oxides played an important role in controlling the environmental behavior of AT in an aquatic environment.展开更多
A treatment unit packed by granular adsorbent of Fe-Mn binary oxide incorporated into diatomite （FMBO（1：1）-diatomite） was studied to remove arsenic from anaerobic groundwater without any pre-treatment or post-tre...A treatment unit packed by granular adsorbent of Fe-Mn binary oxide incorporated into diatomite （FMBO（1：1）-diatomite） was studied to remove arsenic from anaerobic groundwater without any pre-treatment or post-treatment. The raw anaerobic groundwater containing 35-45 μg/L of arsenic was collected from suburb of Beijing. Arsenic（Ⅲ） constituted roughly 60%-80% of the total arsenic content. Approximately 7,000 bed volumes （ratio of effluent volume to adsorbent volume） treated water with arsenic concentration below 10 μg/L were produced in the operation period of four months. The regeneration of FMBO（1：1）-diatomite had been operated for 15 times. In the first stage, the regeneration process significantly improved the adsorption capacity of FMBO（1：1 ）-diatomite. With increased loading amount of Fe-Mn binary oxide, the adsorption capacity for arsenic decreased 20%-40%. Iron and manganese in anaerobic groundwater were oxidized and adsorptive filtrated by FMBO（1 ： 1）-diatomite efficiently. The final concentrations of iron and manganese in effluents were nearly zero. The continued safe performance of the treatment units proved that adsorbent FMBO（1：1）- diatomite had high oxidation ability and exhibited strong adsorptive filtration.展开更多
基金Supported by the National Natural Science Foundation of China(No.50879025)
文摘Artificial neural network（ANN） and full factorial design assisted atrazine（AT） multiple regression adsorption model（AT-MRAM） were developed to analyze the adsorption capability of the main components in the surficial sediments（SSs）. Artificial neural network was used to build a model（the determination coefficient square r2 is 0.9977） to describe the process of atrazine adsorption onto SSs, and then to predict responses of the full factorial design. Based on the results of the full factorial design, the interactions of the main components in SSs on AT adsorption were investigated through the analysis of variance（ANOVA）, F-test and t-test. The adsorption capability of the main components in SSs for AT was calculated via a multiple regression adsorption model（MRAM）. The results show that the greatest contribution to the adsorption of AT on a molar basis was attributed to Fe/Mn（–1.993 μmol/mol）. Organic materials（OMs） and Fe oxides in SSs are the important adsorption sites for AT, and the adsorption capabilities are 1.944 and 0.418 μmol/mol, respectively. The interaction among the non-residual components（Fe, Mn oxides and OMs） in SSs interferes in the adsorption of AT that shouldn’t be neglected, revealing the significant contribution of the interaction among non-residual components to controlling the behavior of AT in aquatic environments.
基金supported d by the National Key Research and Development Program of China(No.2018YFC1802905).
文摘Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II)and Mn(II)by Pseudomonas taiwanensis(marked as P4)and Pseudomonas plecoglossicida(marked as G1)contains rich reactive oxygen functional groups,which play critical roles in the removal efficiency and immobilization of heavymetal(loid)s in co-contamination system.The isolated strains P4 and G1 can growwell in the following environments:pH 5-9,NaCl 0-4%,and temperature 20-30℃.The removal efficiencies of Fe,Pb,As,Zn,Cd,Cu,and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system(the initial concentrations of heavy metal(loid)were 1 mg/L),approximately reaching 96%,92%,85%,67%,70%,54%and 15%,respectively.The exchangeable and carbonate bound As,Cd,Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil,thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s.This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.
基金supported by the National Key Research and Development Program of China(No.2021YFC3200700)the National Natural Science Foundation of China(No.52400010)+1 种基金the Science and Technology Commission of Shanghai Municipality(No.24ZR1472300)the Fundamental Research Funds for the Central Universities.
文摘Bisphenol A(BPA)is a pervasive endocrine disruptor that enters the environment through anthropogenic activities,posing significant risks to ecosystems and human health.Advanced oxidation processes(AOPs)are promising methods for the removal of organic microcontaminants in the environment.Biogenic manganese oxides(BMO)are reported as catalysts due to their transitionmetal nature,and are also readily generated bymanganeseoxidizing microorganisms in the natural environment,and therefore their roles and effects in AOPs-based environmental remediation should be investigated.However,biogenic ironmanganese oxides(BFMO)are actually generated rather than BMO due to the coexistence of ferrous ionswhich can be oxidized to iron oxides.Therefore,this study produced BFMO originating from a highly efficientmanganese-oxidizing fungus Cladosporium sp.XM01 and chose peroxymonosulfate(PMS)as a typical oxidant for the degradation of bisphenol A(BPA),a model organic micropollutant.Characterization results indicate that the formed BFMO was amorphouswith a lowcrystallinity.The BFMO/PMS system achieved a high degradation performance that 85%BPA was rapidly degraded within 60min,and therefore the contribution of BFMO cannot be ignored during PMS-based environmental remediation.Different from the findings of previous studies(mostly radicals and singlet oxygen),the degradationmechanism was first proven as a 100%electron-transfer pathway mediated by high-valence Mn under acidic conditions provided by PMS.The findings of this study provide new insights into the degradation mechanisms of pollutants using biogenic metal oxides in PMS activation and the contribution of their coexistence in AOPs-based environmental remediation.
基金supported by the National Natural Science Foundation of China(Nos.51290282,51578537,51420105012)the National Water Pollution Control and Treatment Science and Technology Major Project(No.2014ZX07405003)
文摘Antimony（Sb）, which can be toxic at relatively low concentrations, may co-exist with Mn（Ⅱ）and/or Fe（Ⅱ） in some groundwater and surface water bodies. Here we investigated the potential oxidation and adsorption pathways of Sb（Ⅲ and V） species in the presence of Mn（Ⅱ） and Mn-oxidizing bacteria, with or without Fe（Ⅱ）. Batch experiments were conducted to determine the oxidation and adsorption characteristics of Sb species in the presence of biogenic Mn oxides（BMOs）, which were formed in-situ via the oxidation of Mn（Ⅱ） by a Mn-oxidizing bacterium（Pseudomonas sp. QJX-1）. Results indicated that Sb（Ⅲ） ions could be oxidized to Sb（V） ions by BMO, but only Sb（V） originating from Sb（Ⅲ） oxidation was adsorbed effectively by BMO. Introduced Fe（Ⅱ） was chemically oxidized to Fe OOH, the precipitates of which mixed with BMO to form a new compound, biogenic Fe–Mn oxides（BFMO）. The BMO part of the BFMO mainly oxidized and the Fe OOH of the BFMO mainly adsorbed the Sb species. In aquatic solutions containing both As（Ⅲ） and Sb（Ⅲ）, the BFMO that formed in-situ preferentially oxidized Sb over As but adsorbed As more efficiently. Chemical analysis and reverse transcription real-time polymerase chain reaction revealed that the presence of Fe（Ⅱ）, As（Ⅲ） and Sb（Ⅲ） accelerated the oxidation of Mn（Ⅱ） but inhibited the activity of Mn-oxidizing bacteria. These results provide significant insights into the biogeochemical pathways of Sb, Mn（Ⅱ） in aquatic ecosystems, with or without Fe（Ⅱ）.
基金supported by the National Key Research and Development Project of China(No.2016YFD0800706)the Science and Technology Project of Fujian Province of China(No.2018Y0080)the Science and Technology Project of Xiamen(No.3502Z20172026)
文摘Cadmium (Cd) and arsenic (As) are two of the most toxic elements.However,the chemical behaviors of these two elements are different,making it challenging to utilize a single adsorbent with high adsorption capacity for both Cd(Ⅱ) and As(Ⅴ) removal.To solve this problem,we synthesized HA/Fe-Mn oxides-loaded biochar (HFMB),a novel ternary material,to perform this task,wherein scanning electron microscopy (SEM) combined with EDS (SEM-EDS) was used to characterize its morphological and physicochemical properties.The maximum adsorption capacity of HFMB was 67.11 mg/g for Cd(Ⅱ) and 35.59 mg/g for As(Ⅴ),which is much higher compared to pristine biochar (11.06 mg/g,0 mg/g for Cd(Ⅱ) and As(Ⅴ),respectively).The adsorption characteristics were investigated by adsorption kinetics and the effects of the ionic strength and pH of solutions.X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) revealed that chelation and deposition were the adsorption mechanisms that bound Cd(Ⅱ) to HFMB,while ligand exchange was the adsorption mechanism that bound As(Ⅴ).
基金supported by the National Key Research and Development Program of China(No.2019YFC0408500)the Scientific Research Project of China State Construction Engineering Corporation Limited(CSCEC-2022-K-(36))the Scientific Research Project of CSCEC AECOM Consultants Corporation Limited(XBSZKY2216).
文摘Anaerobic digestion(AD),as an eco-friendly biological process,shows potential for the decomposition of leachate produced by waste incineration power plants.In this study,the effects of Fe oxides nano-modified pumice(FNP)were investigated on the fresh leachate AD process.Firstly,a simple hydrothermal method was used to prepare FNP,then introduced into the UASB reactor to evaluate its AD efficiency.Results showed that the inclusion of FNP could shorten the lag phase by 10 days compared to the control group.Furthermore,cumulative methane production in the FNP group was enhanced by 20.11%.Mechanistic studies suggested that hydrogenotrophic methanogenesis in the FNP group was more pronounced due to the influence of key enzymes(i.e.,dehydrogenase and coenzyme F420).Microbial community analysis demonstrated that FNP could enhance the abundance of Methanosarcina,Proteobacteria,Sytrophomonas,and Limnobacter,which might elevate enzyme activity involved in methane production.These findings suggest that FNP might mediate interspecies electron transfer among these microorganisms,which is essential for efficient leachate treatment.
基金supported by the National Natural Science Foundation of China(No.41120124003)the Ministry of Science and Technology of China(No.2012AA062602)the 111 project and Priority Development Projects of SRFDP of the Ministry of Education of China
文摘The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. The molar ratio of Fe and Mn in the synthetic Fe-Mn binary oxides was 4 ： 3. The FM-1 and FM-2（prepared at different activation temperatures） having high specific surface areas（358.87 and 128.58 m^2/g, respectively） were amorphous and of nano particle types. The amount of arsenic adsorbed on FM-1 was higher than that adsorbed on FM-2 particles. After adsorption by FM-1, residual arsenic concentration decreased to less than 10 μg/L. The adsorption kinetics data were analyzed using different kinetic models including pseudo first-order model, pseudo second-order model, Elovich model and intraparticle diffusion model. Pseudo second-order kinetic model was the most appropriate model to describe the adsorption kinetics. The adsorption percentage of As（Ⅲ） increased in the p H range of 2–3 while it decreased with the increase of pH（ 3〈pH〈10）. The effects of coexisting anions on As（Ⅲ） removal using FM-1 and FM-2 were also studied and the order of the effects is as follows： NO_3^-, Cl-, F-〈SO_4^（2-）, HCO_3-〈H_2PO_4^-, indicating that H_2PO_4^- is the major competitor with As（Ⅲ） for adsorptive sites on the surface of the adsorbents. The higher adsorption capacity of FM-1 makes it potentially attractive adsorbent for the removal of As（Ⅲ） from groundwater.
基金Project supported by National Natural Science Foundation of China (20773090)the National High Technology Research and Development Program of China (863 Program, 2006AA06Z347)the Youth Fund of Sichuan University (2008119)
文摘A series of Mn-Cu mixed oxide catalysts were prepared by precipitation method. The catalysts were characterized by N2 adsorp- tion-desorption, H2-TPR and XPS. When the loading ratio of manganese oxides to copper oxides was 8：2 or 7：3, the catalysts possessed better catalytic activity, and benzene was converted completely at 558 K. Results of H2-TPR showed that the loading of a small amount of copper oxides decreased the reduction temperature of catalysts. Results of XPS showed that the loading of a small amount of copper oxides increased the proportion of manganese and defective oxygen on the surface of catalysts, and stabilized manganese at higher oxidation state. And the catalyst with the loading ratio 7：3 was a little worse than 8：2, since the interaction between manganese oxides and copper oxides is too strong, copper oxides migrate to the surface of catalysts and manganese oxides in excess are immerged.
基金The National Key Basic Research Program of China under contract Nos 2013CB429700the National Special Fund for the 12th Five Year Plan of COMRA under contract Nos DY125-12-R-02 and DY125-12-R-05+3 种基金the National Natural Science Foundation of China under contract Nos 41325021,40830849,40976027 and 41476044the Shandong Province Natural Science Foundation of China for Distinguished Young Scholars under contract Nos JQ200913the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11030302the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘Utilizing Si, Fe and Mn concentrations within the end-member PACMANUS hydrothermal fluid, Si-Fe-Mn-H2O Pourbaix diagrams were constructed at 300℃and 25℃. ThePourbaix diagrams show that the main Si, Fe and Mn oxides species precipitating from the hydrothermal fluid were SiO2, Fe（OH）3, Fe3（OH）8, Mn3O4, and Mn2O3at 25℃. During mixing of hydrothermal fluid with seawater, SiO2 precipitated earlier than Fe-Mn-oxyhydroxides because of the lower stability boundary. Then Fe（OH）2 precipitated first, followed by Fe3（OH）8 and Fe（OH）3, and last, small amounts of Mn3O4 and Mn2O3 precipitated. Fe（OH）3was readily de-posited in alkaline solution with little influence by Eh. There were many Si-Fe-Mn-concentric particles in the polished sections of the massive precipitates collected from PACMANUS. In the concentric nucleus and ellipsoid, Si oxides precipitated first before the hydrothermal fluid had mixed with seawater. In the concen-tric nucleus, after the precipitation of Si oxides, the increase of pH and Eh promoted the precipitation of Mn oxides around the Si oxides. In the large ellipsoid, the precipitation of Fe was divided into two periods. In the early period, increase of pH value of hydrothermal fluid produced by low-temperature convection and an input of a small volume of seawater promoted a small amount of Fe（OH）3 to precipitate in the Si-rich core. In the late period, after complete mixing with seawater and the resultant fluid was close to neutral or slightly alkaline in pH, Fe（OH）3was easily precipitated from the solution and distributed around the Si-rich core.
基金The National Key Basic Research Program of China under contract No.2013CB429700the National Special Fund for the 12th Five Year Plan of COMRA under contract No.DY125-12-R-05+3 种基金the National Special Fund for the 12th Five Year Plan of COMRA under contract Nos DY125-12-R-02 and DY125-11-R-05the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11030302the National Natural Science Foundation of China under contract Nos 41325021,40830849 and 40976027Shandong Province Natural Science Foundation of China for Distinguished Young Scholars under contract No.JQ200913
文摘Si-Fe-Mn-oxyhydroxides dredged at the PACMANUS （Papua New Guinea-Australia-Canada-Manus） hydrothermal field, Eastern Manus Basin, have 87Sr/SSSr=0.708 079-0.708 581; eNd=5.149 833-6.534 826; 208pb/204pb=38.245-38.440; 207pb/204pb=lS.503-15.560; 206pb/204pb=lS.682-18.783. s7sr/sSSr isotope ratios are relatively homogeneous and close to the value of the surrounding seawater （0.709 16）. The content of Sr in the samples contributed by seawater was estimated to be 76.7%-83.1% of total amount. The mixing temperature of hydrothermal fluids and seawater were ranging from 53.2℃ to 72.2℃ and the hydrothermal activities were unstable when the samples precipitated. The eNd values of all the samples are positive, which differ from the values of ferromanganese nodules （crusts） with hydrogenic origin. Nd was mainly derived from substrate rocks leached by hydrothermal circulation and preserved the hydrothermal signature. Ph isotopic compositions of most samples show minor variability except Sample #9-2 that has relatively high values of Pb isotopes. The Pb may be derived from the Eastern Manus Basin rocks leached by the hydrothermal fluid. The slightly lower 28pb/204pb and 207pb/204pb values of the samples indicated that the hydrothermal circulation in PACMANUS was not entire and sufficient, or that hydrothermal circulation had transient changes in the past. Si-Fe-Mn-oxyhydroxides in the samples preserved the heterogeneities of local rocks.
基金Supported by the National Natural Science Foundation of China(No.50879025)the Scientific Start-up Fund from North China Electric Power University, China(No.X60218)the National Basic Research Program of China(No.2004CB3418501).
文摘To reveal the relative contribution of the components, Fe, Mn oxides or organic materials（OMs） in the surficial sediments（SSs）, and the natural surface coating samples（NSCSs） to adsorbing atrazine（AT）, a selective chemical extraction technique was employed, to remove the different components, and the adsorption characteristics of AT on the SSs and the NSCSs were investigated. The observed adsorptions of AT on the original and extracted SSs and NSCSs were analyzed by nonlinear least squares fitting（NLSF） to estimate the relative contribution of the components. The results showed that the maximum adsorption of AT on the NSCSs was greater than that in the SSs, before and after extraction treatments, implying that the NSCSs were more dominant than the SSs for organic pollutant adsorption. It was also found that the Fe oxides, OMs, and residues in SSs（NSCSs） facilitated the adsorption of AT, but Mn oxides directly or indirectly restrained the interaction of AT with SSs（NSCSs） particles. The contribution of the Fe oxides to AT adsorption was more than that of OMs; the greatest contribution to AT adsorption on a molar basis was from the Fe oxides in the nonresidual fractions, indicating that the Fe oxides played an important role in controlling the environmental behavior of AT in an aquatic environment.
基金supported by the National Natural Science Foundation of China (No.50608067)the Foundation for Creative Research Groups of China (No.50621804)
文摘A treatment unit packed by granular adsorbent of Fe-Mn binary oxide incorporated into diatomite （FMBO（1：1）-diatomite） was studied to remove arsenic from anaerobic groundwater without any pre-treatment or post-treatment. The raw anaerobic groundwater containing 35-45 μg/L of arsenic was collected from suburb of Beijing. Arsenic（Ⅲ） constituted roughly 60%-80% of the total arsenic content. Approximately 7,000 bed volumes （ratio of effluent volume to adsorbent volume） treated water with arsenic concentration below 10 μg/L were produced in the operation period of four months. The regeneration of FMBO（1：1）-diatomite had been operated for 15 times. In the first stage, the regeneration process significantly improved the adsorption capacity of FMBO（1：1 ）-diatomite. With increased loading amount of Fe-Mn binary oxide, the adsorption capacity for arsenic decreased 20%-40%. Iron and manganese in anaerobic groundwater were oxidized and adsorptive filtrated by FMBO（1 ： 1）-diatomite efficiently. The final concentrations of iron and manganese in effluents were nearly zero. The continued safe performance of the treatment units proved that adsorbent FMBO（1：1）- diatomite had high oxidation ability and exhibited strong adsorptive filtration.
