The effects of long-term moisture changes on the migration,release,and bioavailability of selenium in soil are complex.Due to the lack of effective monitoring methods for precise quantification,its dynamic behavior is...The effects of long-term moisture changes on the migration,release,and bioavailability of selenium in soil are complex.Due to the lack of effective monitoring methods for precise quantification,its dynamic behavior is still unclear.Based on the DGT(Diffusive Gradients in Thin-films)technology,this study sets up three moisture control scenarios:continuous wet,wet-dry alternating,and continuous dry,and carries out a 6-month soil moisture control experiment.In the experiment,the DGT device collected the diffusion gradient data of soil selenium under different scenarios,and analyzed the migration characteristics of selenium in combination with the adsorption isotherm.Meanwhile,the release rate,migration coefficient,and bioavailability parameters of selenium are calculated by fitting the first-order kinetic model,further verifying the reliability and applicability of the DGT data.The experimental results demonstrate that under continuous wet conditions,the release rate of soil selenium reaches 1.85µg·cm^(-2)·h^(-1),with a migration coefficient of 0.012 cm^(2)·h^(-1)and a bioavailability parameter of 0.74;under wet-dry alternating conditions,they are 1.42µg·cm^(-2)·h^(-1),0.01 cm^(2)·h^(-1),and 0.68,respectively;under continuous dry conditions,the release rate of soil selenium is the smallest,at 0.88µg·cm^(-2)·h^(-1),with a migration coefficient of 0.004 cm^(-2)·h^(-1)and a bioavailability parameter of 0.5.The results of this experiment reveal the dynamic behavior of soil selenium under different moisture conditions and reflect the high efficiency of DGT technology in dynamic monitoring and quantitative analysis of soil selenium behavior,providing a scientific basis for the optimal management of rhizosphere soil selenium.展开更多
Curvature-driven diffusion (CDD) principles were used to develop a novel gradient based image restora- tion algorithm. The algorithm fills in blocks of missing data in a wireless image after transmission through the n...Curvature-driven diffusion (CDD) principles were used to develop a novel gradient based image restora- tion algorithm. The algorithm fills in blocks of missing data in a wireless image after transmission through the network. When images are transmitted over fading channels, especially in the severe circum- stances of a coal mine, blocks of the image may be destroyed by the effects of noise. Instead of using com- mon retransmission query protocols the lost data is reconstructed by using the adaptive curvature-driven diffusion (ACDD) image restoration algorithm in the gradient domain of the destroyed image. Missing blocks are restored by the method in two steps: In step one, the missing blocks are filled in the gradient domain by the ACDD algorithm; in step two, and the image is reconstructed from the reformed gradients by solving a Poisson equation. The proposed method eliminates the staircase effect and accelerates the convergence rate. This is demonstrated by experimental results.展开更多
An aqueous solution containing sodium polyacrylate（PAAS） was used in diffusive gradient in thin-films technique（DGT） to measure DGT-labile Ni2＋ concentrations.The DGT devices（PAAS DGT） were validated in four ty...An aqueous solution containing sodium polyacrylate（PAAS） was used in diffusive gradient in thin-films technique（DGT） to measure DGT-labile Ni2＋ concentrations.The DGT devices（PAAS DGT） were validated in four types of solutions,including synthetic river water containing metal ions with complexing EDTA or that without complexing EDTA,natural river water（Ling River,Jinzhou,China） spiked with Ni2＋,and an industrial wastewater （Jinzhou,China）.Results show that only free metal ions were measured by PAAS DGT,recovery=97.36% in the solutions containing only free metal ions,recovery=49.62% in a solution with metal/EDTA molar ratio of 2：1 and recovery=0 in the solutions with metal/EDTA molar ratios of 1：1 and 1：2.These indicated that the complexes of Ni-EDTA were DGT-inert.The DGT performance in spiked river water（recovery=18.24%） and in industrial wastewater（recovery=12.25%） were investigated,which indicated that the measurement of metals by this DGT device did not include the humic substances complexed fractions of metals.The binding properties of PAAS DGT for Ni2＋ were investigated under different conditions of pH value and ionic strength.Conditional stability constants（lgK） of PAAS-Ni complexes were also evaluated.展开更多
Cadmium(Cd)uptake by plants or benthic organisms largely depends on its bioavailability in sediments,so it is necessary to understand Cd bio availability for determining its ecological risks in riverine sediments.Pore...Cadmium(Cd)uptake by plants or benthic organisms largely depends on its bioavailability in sediments,so it is necessary to understand Cd bio availability for determining its ecological risks in riverine sediments.Pore water is easily disturbed during sample collection,indicating that there was a shortage of traditional methods for investigating Cd bio availability.Here,sediment cores were collected from rivers,after which sequential extraction and diffusive gradients in thin films(DGT)method were employed to determine Cd potential bio availability in the sediments and pore water.We found that Cd concentrations measured by DGT were lower than that in pore water profiles,and Cd distribution in various fractions changed remarkably.Pearson correlation analysis showed significant positive correlations between Cd concentrations measured by DGT and total Cd concentrations(r^2=0.76),exchangeable and weak acid soluble fraction(r^2=0.68),ferromanganese fraction(r^2=0.72)and bound organic matter or oxidizable fraction(r^2=0.54).However,the correlation was relatively low between Cd concentrations measured by DGT and that in pore water profiles(r^2=0.26).These results demonstrated that DGT method could provide more accurate information of Cd bio availability in sediment profiles than traditional methods.展开更多
In situ NMR measurements of the diffusion coefficients,including an estimate of signal strength,of lithium ion conductor using diffusion-weighting pulse sequence are performed in this study.A cascade bilinear model is...In situ NMR measurements of the diffusion coefficients,including an estimate of signal strength,of lithium ion conductor using diffusion-weighting pulse sequence are performed in this study.A cascade bilinear model is proposed to estimate the diffusion sensitivity factors of pulsed-field gradient using prior information of the electrochemical performance and Arrhenius constraint.The model postulates that the active lithium nuclei participating electrochemical reaction are relevant to the NMR signal intensity,when discharge rate or temperature condition is varying.The electrochemical data and the NMR signal strength show a highly fit with the proposed model according our simulation and experiments.Furthermore,the diffusion time is constrained by temperature based on Arrhenius equation of reaction rates dependence.An experimental calculation of Li_4Ti_5O_（12）（LTO）/carbon nanotubes（CNTs） with the electrolyte evaluating at 20 ℃ is presented,which the b factor is estimated by the discharge rate.展开更多
The passive sampling technique, diffusive gradients in thin films(DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per-and polyfluoroalkyl substances(PFAS). However, its...The passive sampling technique, diffusive gradients in thin films(DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per-and polyfluoroalkyl substances(PFAS). However, its effectiveness has been questioned because of the small effective sampling area(3.1 cm^(2)). In this study, we developed a DGT probe for rapid sampling of eight PFAS in waters and applied it to a water-sediment system. It has a much larger sampling area(27 cm^(2)) and as a result lower method quantification limits(0.15 –0.21 ng/L for one-day deployment and 0.02 – 0.03 ng/L for one-week deployment) and much higher(by > 10 factors) sampling rate(100 m L/day) compared to the standard DGT(piston configuration). The sampler could linearly accumulate PFAS from wastewater, was sensitive enough even for a 24 hr deployment with performance comparable to grab sampling(500m L). The DGT probe provided homogeneous sampling performance along the large exposure area. The use of the probe to investigate distributions of dissolved PFAS around the sediment-water interface was demonstrated. This work, for the first time, demonstrated that the DGT probe is a promising monitoring tool for trace levels of PFAS and a research tool for studying their distribution, migration, and fate in aquatic environments including the sediment-water interface.展开更多
Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in re...Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in recent decades.This study evaluated the bioavailability of metals(Cu,Pb,Cd,Cr and Zn)in the sediment of the southern coastal wetland of the Qiangtang Es-tuary using diffusive gradients in thin films(DGT)techniques and compared with several methods based on total metal content.The results showed that the contents of Cr,Pb,Cd and Cu in sediment,as detected using DGT,were considerably correlated with the exchangeable fraction and the content in Phragmites australis roots,while a weak correlation was observed for Zn.Therefore,DGT analysis could be used to evaluate the bioavailability and potential risk of Cr,Cd,Pb and Cu for P.australis.Quantitative indices,such as DGT concentration,bioaccumulation in P.australis,geoaccumulation index(Igeo)and potential ecological risk index(RI),revealed that Cd was a major potential ecological risk factor along the southern coast wetland of the Qiantang Estuary,especially in the upstream region,which is potentially more vulnerable to the anthropogenic pollution.展开更多
The developed technique of diffusive gradients in thin film( DGT) has been suggested as a promising tool for evaluation of cadmium( Cd) availability in soils,but there exists considerable debate on its suitability. In...The developed technique of diffusive gradients in thin film( DGT) has been suggested as a promising tool for evaluation of cadmium( Cd) availability in soils,but there exists considerable debate on its suitability. In this study,Cd bioavailability in soils was systemically investigated by comparing this technique with seven traditional methods, including soil solution concentration and six commonly used extraction methods( HAc,EDTA,Na c,NH4Ac,CaCl2 and MgCl2). Two typical plants( wheat and maize) were examined for Cd uptake. Maize was more sensitive to increasing exposure to Cd in soils than wheat when the added amounts of Cd ranged from 3. 5 to 5. 0 mg · kg-1,accompanied by the significant decreases of shoot and root biomasses. Cd concentrations in shoots and roots of two plants increased continuously with increasing levels of Cd in soils. Cd uptake was higher in wheat than that in maize. The bioavailable concentrations of Cd measured by all methods increased nearly linearly with increasing addition of Cd in soils. Positive correlations were observed between various bioavailable indicators of Cd in soils and Cd concentrations in two plants. The extractable Cd by six chemical extractants was considerably higher for maize than for wheat,while the DGT-measured and soil solution concentrations of Cd were lower for maize than for wheat,following the same trend as plant Cd uptake. The results imply that DGT measurement can effectively predict the bioavailable levels of Cd in soil solutions and that it is an ideal tool for prediction of Cd bioavailability in soils.展开更多
Soil bioaccessible and labile As were extracted using in vitro,diffusive gradients in thin films(DGT)and chemical extraction methods.The results showed that As(Ⅲ)was readily converted to As(Ⅴ)in the soils,which was ...Soil bioaccessible and labile As were extracted using in vitro,diffusive gradients in thin films(DGT)and chemical extraction methods.The results showed that As(Ⅲ)was readily converted to As(Ⅴ)in the soils,which was promoted by alkaline conditions and higher content of easily reducible Mn.As(Ⅴ)was not readily reduced to As(Ⅲ)in these soils.The effect of soil pH on bioaccessible As content by in vitro method and labile As content by DGT methodwere inconsistent among different soils due to the coincidence of As(Ⅲ)and As(Ⅴ),with As(Ⅲ)being more readily mobilized in acidic environment while the opposite was true for As(Ⅴ).The labile As extracted by phosphate was significantly correlated with that extracted by in vitro method,while the labile As extracted by the DGT was correlated with that extracted by the CaCl_(2) method.The labile As extracted by the DGT was much lower than that by the in vitro and phosphate methods.The in vitro and phosphate methods extracted As in soils which is tightly bound to Fe oxides through dissolution,complexation and ion exchange.In contrast,the DGT method relied on the adsorption of soil labile As onto ZrO-based binding layer.The higher contents of soil Fe oxides and greater adsorption capacity for As led to the lower content of As measured by the DGT method.In conclusion,the in vitro and phosphate extraction are potential to be used to predict soil bioaccessible As.The DGT method is more suitable for ecological risk prediction.展开更多
Traditional studies on transforming selenate and selenite are often limited by static measurements and low spatial resolution.They do not fully consider the impact of moisture content.This paper uses the DGT(diffusive...Traditional studies on transforming selenate and selenite are often limited by static measurements and low spatial resolution.They do not fully consider the impact of moisture content.This paper uses the DGT(diffusive gradients in thin films)technique to deeply explore how moisture changes affect the transformation of selenate and selenite in the environment(changes in properties over time).First,representative soil samples(loess)are prepared,and their moisture content is adjusted.Fixed concentrations of selenate and selenite are added,and then the DGT device simulates their migration in the natural environment.The experiment covers drought,moisture,and high moisture environments,and the experiment is repeated under each condition to ensure the accuracy of the data.The sample quality is verified and further analyzed by ion chromatography(IC)and atomic absorption spectroscopy(AAS).This article uses DGT technology to study the influence of moisture content on the migration and transformation of selenate and selenite in soil.Results indicate that increased moisture content leads to higher concentrations,diffusion rates,and DGT capture efficiency of both selenium species,highlighting the importance of moisture in their environmental behavior.When the moisture content increased from 25%to 65%,the coefficient of variation of selenate and selenite increased.The DGT technique proved effective in capturing spatial heterogeneity and providing high-precision measurements,offering robust data to advance research on selenium behavior in soils.展开更多
A pot experiment was conducted with multi-metal （Pb, Cd, Cu, and Zn） contaminated acidic soil to investigate changes in available metal burden resulting from the application of industrial wastes （fly ash and steel ...A pot experiment was conducted with multi-metal （Pb, Cd, Cu, and Zn） contaminated acidic soil to investigate changes in available metal burden resulting from the application of industrial wastes （fly ash and steel slag）. The efficiency of amendments- induced metal stabilization was evaluated by diffusive gradients in thin films （DGT）, sequential extraction, and plant uptake. The stability of remediation was assessed by an acidification test and by chemical equilibrium modeling. Addition of fly ash （20 g kg-1） and steel slag （3 g kg-1） resulted in similar increase in soil pH. Both amendments significantly decreased the concentrations of metals measured with DGT （CDGT） and the metal uptake by Oryza sativa L. Significant correlations were found between CDGT and the concentration of a combination of metal fractions （exchangeable, bound to carbonates, and bound to Fe/Mn oxides）, unraveling the labile species that participate in the flux of metal resupply. The capability of metal resupply, as reflected by the R （ratio of CDGT to pore water metal concentration） values, significantly decreased in the amended soils. The CDGT correlated well with the plant uptake, suggesting that DGT is a good indicator for bioavailability. Acidification raised the extractable metal concentration in amended soil but the concentration did not return to the pre-amendment level. Equilibrium modeling indicated that the soil amendments induced the precipitation of several Fe, A1 and Ca minerals, which may play a positive role in metal stabilization. Chemical stabilization with alkaline amendments could be an effective and stable soil remediation strategy for attenuating metal bioavailability and reducing plant metal uptake.展开更多
Total contents of metals in soil and sediments on the Tibetan Plateau of China have been widely analyzed,but existing information is insufficient to effectively evaluate metal ecological risk because of a lack of meta...Total contents of metals in soil and sediments on the Tibetan Plateau of China have been widely analyzed,but existing information is insufficient to effectively evaluate metal ecological risk because of a lack of metal bioavailability data.In this study,distribution,potential risk,mobility and bioavailability of metals in sediments of Lake Yamdrok Basin in Tibet of China were explored by combined use of total digestion,sequential extraction and the diffusive gradient in thin-films(DGT).Average concentrations of Cr,Ni,Cu,Zn,As,Cd and Pb in surface sediments were 31.25,30.31,22.00,45.04,31.32,0.13 and 13.39 mg/kg,respectively.Higher levels of metals were found near the inflowing rivers.Residual form was dominant in Cr,Ni,Zn,Cd and Pb,and reducible form was dominant in As and Cd.Metals in surface sediments showed a low enrichment degree overall,but Cd and As had higher ecological risk levels than the other metals.Furthermore,there was a larger average proportion of exchangeable form of As(20.4%)and Cd(9.0%)than the other metals(1.7%-3.3%),implying their higher mobility and release risk.Average DGT-labile concentrations of Cr,Ni,Cu,Zn,As,Cd and Pb were 0.5,4.5,0.7,25.1,60.0,0.22 and 1.0μg/L,respectively.The DGT-labile As was significantly correlated with extractable As forms(p<0.01),suggesting that extractable As in sediments acts as a"mobile pool"for bioavailable As.These results suggest potential risks of As and Cd,especially As,deserve further attention in Lake Yamdrok Basin.展开更多
A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed ...A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- （up to 106 g/L）, SO42- （up to 16 g/L）, HCO3- （up to 817 g/L）, and AsO2- and AsO 3 4 （both up to 1 mg As/L） in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH （4.2-9.2）. The lowest capacity （95 μg P/m2 at pH 9.2） was still greater than that of other DGT techniques that are usually used for the measurement of DRP （2-12 μg P/cm2 ）. The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices （6 months）. The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.展开更多
Macrophytes are usually chosen for phytoremediation tools to remove P in eutrophic aquatic ecosystems,but the lack of test methods hinders the understanding of removal mechanism and application.In this study,we used t...Macrophytes are usually chosen for phytoremediation tools to remove P in eutrophic aquatic ecosystems,but the lack of test methods hinders the understanding of removal mechanism and application.In this study,we used the novel technologies combined of Diffusive gradients in thin films(DGT),Planar optode(PO),and Non-invasive micro-test technology(NMT)to explore P dynamics in water-sediment continuum and rhizosphere of Potamogeton crispus over time.Results of the high-resolution in situ measurement showed that labile P(LPDGT)fluxes at the surficial sediment significantly decreased from approximate 120,140,and 200 pg/(cm^(2)·sec)via 30 days incubation period to 17,40,and 56 pg/(cm2•sec)via that of 15 days.Obvious synchronous increase of LPDGT was not detected in overlying water,suggesting the intense assimilation of dissolve reactive P via root over time.PO measurement indicated that O_(2)concentration around the rhizosphere remarkably increased and radially diffused into deeper sediment until 100%saturation along with the root stretch downwards.NMT detection of roots showed the obvious O_(2)inflow into root tissue with the uppermost flux of 30 pmol/(cm2•sec)from surroundings via aerenchyma on different treatment conditions.Different from previous reports,gradually saturating O_(2)concentrations around the rhizosphere was principally driven by O_(2)penetration through interspace attributing to root stretch downward rather than root O_(2)leakage.Increased O_(2)concentrations in deep sediment over time finally induced the oxidization of labile Fe(II)into Fe(III)bound P and local P immobilization.展开更多
The technique of DGT（diffusive gradients in thin films） using three diffusive gel thicknesses was applied to estimate the mobility and bioavailability of heavy metals in sediments and porewater of Lake Taihu, China....The technique of DGT（diffusive gradients in thin films） using three diffusive gel thicknesses was applied to estimate the mobility and bioavailability of heavy metals in sediments and porewater of Lake Taihu, China. The DGT results showed significantly positive correlations between Co, Pb, Cd and Mn, and Ni and Fe concentrations in porewater. Cu and Zn showed a significantly negative correlation with Mn, due to Cu combination with carbonates and Zn derived from agricultural pollution, respectively. The rank order of average concentrations of Co, Ni and Cd at each station was DGT1.92〉DGT0.78〉 DGT0.39, suggesting stronger resupply from sediments to porewater when using thicker diffusive gels. Comparing centrifugation and DGT measurements, Co, Ni and Cd are highly labile; Mn and Fe are moderately labile; and Cu, Zn and Pb are slightly labile. The variations of AVS concentrations in sediment cores indicate that metal sulfides in deeper layers are easily diffused into surface sediments.展开更多
A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional e...A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass(Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT(CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt(Na2EDTA)- and acetic acid(HOAc)-extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perenne was negatively influenced by p H and positively influenced by organic matter(OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA- and HOAc-extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were p H and OM dependent. For CE, the relationship was p H independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability.展开更多
Diffusive gradients in thin films(DGT)measurements have been shown to outperform other phosphorus(P)tests in soils with strong P sorption,but this has not been confirmed for moderately weathered European soils.We comp...Diffusive gradients in thin films(DGT)measurements have been shown to outperform other phosphorus(P)tests in soils with strong P sorption,but this has not been confirmed for moderately weathered European soils.We compared the performance of DGT in predicting wheat grain yield in Swedish long-term fertility experiments with those of standard intensity(water-extractable P(P-H2O))and quantity(ammonium lactate-extractable P(P-AL))tests.A Mitscherlich-type model was used to fit wheat yield response to P application rates(0,15,30 or 35,and 45 kg P ha-1 year-1)in each individual trial replicate to estimate the maximum yield.For trials with clear plateau-type yield responses and the goodness of fit(R2)>0.75,relative yields(RYs)were calculated for each P treatment and plotted against the soil P test results(n=143).The goodness of the Mitscherlich-type fits decreased in the following order:DGT-measured P(P-DGT)(R2=0.35)>P-H2O(R2=0.18)>P-AL(R2=0.13).When excluding soils with P-AL:P-DGT≥0.1 L g-1,R2 was considerably improved to 0.55 for P-AL,0.46 for P-H2O,and 0.65 for P-DGT(n=61).At 95%of maximum yield,the upper limit of P deficiency for P-DGT was 44.8(the soils with P-AL:P-DGT<0.1 L g-1)and 61.9μg L-1(all soils),falling within the range reported for other European and Australian soils(6.0–142μg L-1).We show that in the investigated Swedish soils,DGT performed better than the quantity and intensity tests,which is attributed to its ability to capture P diffusion and resupply from the soil solid phase,similar to plant roots in the rhizosphere.展开更多
On the basis of the detailed field work, compositions and contents of plagioclase and K - feldspar,determination of ordering degree, statistical analysis of plagioclase elongation index, mass-balance calculation and m...On the basis of the detailed field work, compositions and contents of plagioclase and K - feldspar,determination of ordering degree, statistical analysis of plagioclase elongation index, mass-balance calculation and mineral spatial distribution and geochemistry, it is concluded that the migmatites in the Dabie complex are characterized by the presence of thermocenters. There are regular changes in mineral character in the migmatites from the centers outwards. The dominant genetic mechanism is anatexis and metasomatism, whose intensities decrease from the centers outwards. Finally, according to the simulated experiment on Liesegang' s rings and non-linear dynamics (dissipative structure theory), the dynamic mechanism of migmatization is profoundly expouded as consisting of the early-stage metasomatism induced by the thermal anomaly, the cardinal-stage anatexis induced by the early-stage matasomatism and finally the last-stage post-anatexis metasomatism.展开更多
Urban wastewater is one of main sources for the introduction of antibiotics into the environment.Monitoring the concentrations of antibiotics in wastewater is necessary for estimating the amount of antibiotics dischar...Urban wastewater is one of main sources for the introduction of antibiotics into the environment.Monitoring the concentrations of antibiotics in wastewater is necessary for estimating the amount of antibiotics discharged into the environment through urban wastewater treatment systems.In this study,we report a novel diffusive gradient in thin films(DGT)method based on molecularly imprinted polymers(MIPs)for in situ measurement of two typical antibiotics,fluoroquinolones(FQs)and sulfonamides(SAs)in urban wastewater.MIPs show specific adsorption toward their templates and their structural analogs,resulting in the selective uptake of the two target antibiotics during MIP-DGT deployment.The uptake performance of the MIP-DGTs was evaluated in the laboratory and was relatively independent of solution pH(4.0-9.0),ionic strength(1-750 mmol/L),and dissolved organic matter(DOM,0-20 mg/L).MIP-DGT samplers were tested in the effluent of an urban wastewater treatment plant for field trials,where three SA(sulfamethoxazole,sulfapyridine,and trimethoprim)and one FQ(ofloxacin)antibiotics were detected,with concentrations ranging from 25.50 to 117.58 ng/L,which are consistent with the results measured by grab sampling.The total removal efficiency of the antibiotics was 80.1%by the treatment plant.This study demonstrates that MIP-DGT is an effective tool for in situ monitoring of trace antibiotics in complex urban wastewaters.展开更多
Photoenergy harvesting is promising to power Internet-of-Things(IoT)sensors,freeing the limitations of wired power sources or batteries,enabling bio-integrated devices.However,existing photoenergy harvesting systems a...Photoenergy harvesting is promising to power Internet-of-Things(IoT)sensors,freeing the limitations of wired power sources or batteries,enabling bio-integrated devices.However,existing photoenergy harvesting systems are restricted to solid or liquid configurations—limiting biocompatibility and space utilization—which makes obtaining flexible,biocompatible,light-harvesting devices a significant challenge.In this paper,inspired by natural ion gradient diffusion in organisms,offering an ion-hydrogel drops-based photoenergy harvesting base on ammonium molybdate.Through the photochemical process of ammonium molybdate,the electric potential of the device is regulated by the altered ion gradient and the redox pairs([Mo_(7)O_(24)]^(6-)/[Mo_(1)O_(46)]^(10-)),to generate energy.When exposed to excitation light,a photo driven ammonium molybdate-hydrogel photoenergy harvester(PAPH)can generate an open-circuit potential of~250 mV,and it can still obtain a considerable output power for milliseconds to thousands of seconds after the termination of the initial illumination.The reversible hydrogel droplets network allows for the recovery and fabrication of arbitrary structures of the PAPH.We further demonstrate the scalable PAPH networks can on-demand regulation of cell epithelial growth factor secretion and receptor expression,stimulate the cell proliferation,thereby facilitating biological tissue wound repair.This ionic hydrogel opens a new avenue for flexible,photoenergy harvesting,biocompatible devices.展开更多
文摘The effects of long-term moisture changes on the migration,release,and bioavailability of selenium in soil are complex.Due to the lack of effective monitoring methods for precise quantification,its dynamic behavior is still unclear.Based on the DGT(Diffusive Gradients in Thin-films)technology,this study sets up three moisture control scenarios:continuous wet,wet-dry alternating,and continuous dry,and carries out a 6-month soil moisture control experiment.In the experiment,the DGT device collected the diffusion gradient data of soil selenium under different scenarios,and analyzed the migration characteristics of selenium in combination with the adsorption isotherm.Meanwhile,the release rate,migration coefficient,and bioavailability parameters of selenium are calculated by fitting the first-order kinetic model,further verifying the reliability and applicability of the DGT data.The experimental results demonstrate that under continuous wet conditions,the release rate of soil selenium reaches 1.85µg·cm^(-2)·h^(-1),with a migration coefficient of 0.012 cm^(2)·h^(-1)and a bioavailability parameter of 0.74;under wet-dry alternating conditions,they are 1.42µg·cm^(-2)·h^(-1),0.01 cm^(2)·h^(-1),and 0.68,respectively;under continuous dry conditions,the release rate of soil selenium is the smallest,at 0.88µg·cm^(-2)·h^(-1),with a migration coefficient of 0.004 cm^(-2)·h^(-1)and a bioavailability parameter of 0.5.The results of this experiment reveal the dynamic behavior of soil selenium under different moisture conditions and reflect the high efficiency of DGT technology in dynamic monitoring and quantitative analysis of soil selenium behavior,providing a scientific basis for the optimal management of rhizosphere soil selenium.
基金supported by the National High-Tech Research and Development Program of China (No. 2008AA062200)the National Natural Science Foundation of China (No.60802077)the Fundamental Research Funds for the Central Universities (No. 2010QNA43)
文摘Curvature-driven diffusion (CDD) principles were used to develop a novel gradient based image restora- tion algorithm. The algorithm fills in blocks of missing data in a wireless image after transmission through the network. When images are transmitted over fading channels, especially in the severe circum- stances of a coal mine, blocks of the image may be destroyed by the effects of noise. Instead of using com- mon retransmission query protocols the lost data is reconstructed by using the adaptive curvature-driven diffusion (ACDD) image restoration algorithm in the gradient domain of the destroyed image. Missing blocks are restored by the method in two steps: In step one, the missing blocks are filled in the gradient domain by the ACDD algorithm; in step two, and the image is reconstructed from the reformed gradients by solving a Poisson equation. The proposed method eliminates the staircase effect and accelerates the convergence rate. This is demonstrated by experimental results.
文摘An aqueous solution containing sodium polyacrylate（PAAS） was used in diffusive gradient in thin-films technique（DGT） to measure DGT-labile Ni2＋ concentrations.The DGT devices（PAAS DGT） were validated in four types of solutions,including synthetic river water containing metal ions with complexing EDTA or that without complexing EDTA,natural river water（Ling River,Jinzhou,China） spiked with Ni2＋,and an industrial wastewater （Jinzhou,China）.Results show that only free metal ions were measured by PAAS DGT,recovery=97.36% in the solutions containing only free metal ions,recovery=49.62% in a solution with metal/EDTA molar ratio of 2：1 and recovery=0 in the solutions with metal/EDTA molar ratios of 1：1 and 1：2.These indicated that the complexes of Ni-EDTA were DGT-inert.The DGT performance in spiked river water（recovery=18.24%） and in industrial wastewater（recovery=12.25%） were investigated,which indicated that the measurement of metals by this DGT device did not include the humic substances complexed fractions of metals.The binding properties of PAAS DGT for Ni2＋ were investigated under different conditions of pH value and ionic strength.Conditional stability constants（lgK） of PAAS-Ni complexes were also evaluated.
基金supported by the Youth Innovation Promotion Association CAS(Wenzhong Tang,2017059)the National Natural Science Foundation of China(No.41877368)
文摘Cadmium(Cd)uptake by plants or benthic organisms largely depends on its bioavailability in sediments,so it is necessary to understand Cd bio availability for determining its ecological risks in riverine sediments.Pore water is easily disturbed during sample collection,indicating that there was a shortage of traditional methods for investigating Cd bio availability.Here,sediment cores were collected from rivers,after which sequential extraction and diffusive gradients in thin films(DGT)method were employed to determine Cd potential bio availability in the sediments and pore water.We found that Cd concentrations measured by DGT were lower than that in pore water profiles,and Cd distribution in various fractions changed remarkably.Pearson correlation analysis showed significant positive correlations between Cd concentrations measured by DGT and total Cd concentrations(r^2=0.76),exchangeable and weak acid soluble fraction(r^2=0.68),ferromanganese fraction(r^2=0.72)and bound organic matter or oxidizable fraction(r^2=0.54).However,the correlation was relatively low between Cd concentrations measured by DGT and that in pore water profiles(r^2=0.26).These results demonstrated that DGT method could provide more accurate information of Cd bio availability in sediment profiles than traditional methods.
基金supported by the National Major Scientific Equipment R&D Project (No. ZDYZ2010-2)the National Natural Science Foundation of China (No. 51307165)
文摘In situ NMR measurements of the diffusion coefficients,including an estimate of signal strength,of lithium ion conductor using diffusion-weighting pulse sequence are performed in this study.A cascade bilinear model is proposed to estimate the diffusion sensitivity factors of pulsed-field gradient using prior information of the electrochemical performance and Arrhenius constraint.The model postulates that the active lithium nuclei participating electrochemical reaction are relevant to the NMR signal intensity,when discharge rate or temperature condition is varying.The electrochemical data and the NMR signal strength show a highly fit with the proposed model according our simulation and experiments.Furthermore,the diffusion time is constrained by temperature based on Arrhenius equation of reaction rates dependence.An experimental calculation of Li_4Ti_5O_（12）（LTO）/carbon nanotubes（CNTs） with the electrolyte evaluating at 20 ℃ is presented,which the b factor is estimated by the discharge rate.
基金supported by the Key Deployment Project of Centre for Ocean Mega-Research of Science, Chinese Academy of Sciences (No. COMS2019J08)the Guangzhou Municipal Science and Technology Project (No. 201904010291)+1 种基金National Natural Science Foundation of China (No. 21806042)Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety (No. 2019B030301008)。
文摘The passive sampling technique, diffusive gradients in thin films(DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per-and polyfluoroalkyl substances(PFAS). However, its effectiveness has been questioned because of the small effective sampling area(3.1 cm^(2)). In this study, we developed a DGT probe for rapid sampling of eight PFAS in waters and applied it to a water-sediment system. It has a much larger sampling area(27 cm^(2)) and as a result lower method quantification limits(0.15 –0.21 ng/L for one-day deployment and 0.02 – 0.03 ng/L for one-week deployment) and much higher(by > 10 factors) sampling rate(100 m L/day) compared to the standard DGT(piston configuration). The sampler could linearly accumulate PFAS from wastewater, was sensitive enough even for a 24 hr deployment with performance comparable to grab sampling(500m L). The DGT probe provided homogeneous sampling performance along the large exposure area. The use of the probe to investigate distributions of dissolved PFAS around the sediment-water interface was demonstrated. This work, for the first time, demonstrated that the DGT probe is a promising monitoring tool for trace levels of PFAS and a research tool for studying their distribution, migration, and fate in aquatic environments including the sediment-water interface.
基金the Natural Science Foun-dation of China(No.41776119)Zhejiang Provincial Natural Science Foundation of China(No.LY15D060004)for the financial support.
文摘Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in recent decades.This study evaluated the bioavailability of metals(Cu,Pb,Cd,Cr and Zn)in the sediment of the southern coastal wetland of the Qiangtang Es-tuary using diffusive gradients in thin films(DGT)techniques and compared with several methods based on total metal content.The results showed that the contents of Cr,Pb,Cd and Cu in sediment,as detected using DGT,were considerably correlated with the exchangeable fraction and the content in Phragmites australis roots,while a weak correlation was observed for Zn.Therefore,DGT analysis could be used to evaluate the bioavailability and potential risk of Cr,Cd,Pb and Cu for P.australis.Quantitative indices,such as DGT concentration,bioaccumulation in P.australis,geoaccumulation index(Igeo)and potential ecological risk index(RI),revealed that Cd was a major potential ecological risk factor along the southern coast wetland of the Qiantang Estuary,especially in the upstream region,which is potentially more vulnerable to the anthropogenic pollution.
基金National Natural Science Foundation of China(No.41001334)Fundamental Research Funds for the Central Universities,China(No.2009B00814)+1 种基金the Project of Knowledge Innovation for the 3rd period,the Chinese Academy of Sciences(No.KZCX2-YW-JS304)Project of the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘The developed technique of diffusive gradients in thin film( DGT) has been suggested as a promising tool for evaluation of cadmium( Cd) availability in soils,but there exists considerable debate on its suitability. In this study,Cd bioavailability in soils was systemically investigated by comparing this technique with seven traditional methods, including soil solution concentration and six commonly used extraction methods( HAc,EDTA,Na c,NH4Ac,CaCl2 and MgCl2). Two typical plants( wheat and maize) were examined for Cd uptake. Maize was more sensitive to increasing exposure to Cd in soils than wheat when the added amounts of Cd ranged from 3. 5 to 5. 0 mg · kg-1,accompanied by the significant decreases of shoot and root biomasses. Cd concentrations in shoots and roots of two plants increased continuously with increasing levels of Cd in soils. Cd uptake was higher in wheat than that in maize. The bioavailable concentrations of Cd measured by all methods increased nearly linearly with increasing addition of Cd in soils. Positive correlations were observed between various bioavailable indicators of Cd in soils and Cd concentrations in two plants. The extractable Cd by six chemical extractants was considerably higher for maize than for wheat,while the DGT-measured and soil solution concentrations of Cd were lower for maize than for wheat,following the same trend as plant Cd uptake. The results imply that DGT measurement can effectively predict the bioavailable levels of Cd in soil solutions and that it is an ideal tool for prediction of Cd bioavailability in soils.
基金supported by the National Key R&D Program of China(No.2020YFC1806801).
文摘Soil bioaccessible and labile As were extracted using in vitro,diffusive gradients in thin films(DGT)and chemical extraction methods.The results showed that As(Ⅲ)was readily converted to As(Ⅴ)in the soils,which was promoted by alkaline conditions and higher content of easily reducible Mn.As(Ⅴ)was not readily reduced to As(Ⅲ)in these soils.The effect of soil pH on bioaccessible As content by in vitro method and labile As content by DGT methodwere inconsistent among different soils due to the coincidence of As(Ⅲ)and As(Ⅴ),with As(Ⅲ)being more readily mobilized in acidic environment while the opposite was true for As(Ⅴ).The labile As extracted by phosphate was significantly correlated with that extracted by in vitro method,while the labile As extracted by the DGT was correlated with that extracted by the CaCl_(2) method.The labile As extracted by the DGT was much lower than that by the in vitro and phosphate methods.The in vitro and phosphate methods extracted As in soils which is tightly bound to Fe oxides through dissolution,complexation and ion exchange.In contrast,the DGT method relied on the adsorption of soil labile As onto ZrO-based binding layer.The higher contents of soil Fe oxides and greater adsorption capacity for As led to the lower content of As measured by the DGT method.In conclusion,the in vitro and phosphate extraction are potential to be used to predict soil bioaccessible As.The DGT method is more suitable for ecological risk prediction.
文摘Traditional studies on transforming selenate and selenite are often limited by static measurements and low spatial resolution.They do not fully consider the impact of moisture content.This paper uses the DGT(diffusive gradients in thin films)technique to deeply explore how moisture changes affect the transformation of selenate and selenite in the environment(changes in properties over time).First,representative soil samples(loess)are prepared,and their moisture content is adjusted.Fixed concentrations of selenate and selenite are added,and then the DGT device simulates their migration in the natural environment.The experiment covers drought,moisture,and high moisture environments,and the experiment is repeated under each condition to ensure the accuracy of the data.The sample quality is verified and further analyzed by ion chromatography(IC)and atomic absorption spectroscopy(AAS).This article uses DGT technology to study the influence of moisture content on the migration and transformation of selenate and selenite in soil.Results indicate that increased moisture content leads to higher concentrations,diffusion rates,and DGT capture efficiency of both selenium species,highlighting the importance of moisture in their environmental behavior.When the moisture content increased from 25%to 65%,the coefficient of variation of selenate and selenite increased.The DGT technique proved effective in capturing spatial heterogeneity and providing high-precision measurements,offering robust data to advance research on selenium behavior in soils.
基金Supported by the NSFC-Guangdong Joint Foundation of China(No.U0833004)the National Natural Science Foundation of China(No.41101483)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2011),China
文摘A pot experiment was conducted with multi-metal （Pb, Cd, Cu, and Zn） contaminated acidic soil to investigate changes in available metal burden resulting from the application of industrial wastes （fly ash and steel slag）. The efficiency of amendments- induced metal stabilization was evaluated by diffusive gradients in thin films （DGT）, sequential extraction, and plant uptake. The stability of remediation was assessed by an acidification test and by chemical equilibrium modeling. Addition of fly ash （20 g kg-1） and steel slag （3 g kg-1） resulted in similar increase in soil pH. Both amendments significantly decreased the concentrations of metals measured with DGT （CDGT） and the metal uptake by Oryza sativa L. Significant correlations were found between CDGT and the concentration of a combination of metal fractions （exchangeable, bound to carbonates, and bound to Fe/Mn oxides）, unraveling the labile species that participate in the flux of metal resupply. The capability of metal resupply, as reflected by the R （ratio of CDGT to pore water metal concentration） values, significantly decreased in the amended soils. The CDGT correlated well with the plant uptake, suggesting that DGT is a good indicator for bioavailability. Acidification raised the extractable metal concentration in amended soil but the concentration did not return to the pre-amendment level. Equilibrium modeling indicated that the soil amendments induced the precipitation of several Fe, A1 and Ca minerals, which may play a positive role in metal stabilization. Chemical stabilization with alkaline amendments could be an effective and stable soil remediation strategy for attenuating metal bioavailability and reducing plant metal uptake.
基金supported by the National Natural Science Foundation of China(No.42202018027)。
文摘Total contents of metals in soil and sediments on the Tibetan Plateau of China have been widely analyzed,but existing information is insufficient to effectively evaluate metal ecological risk because of a lack of metal bioavailability data.In this study,distribution,potential risk,mobility and bioavailability of metals in sediments of Lake Yamdrok Basin in Tibet of China were explored by combined use of total digestion,sequential extraction and the diffusive gradient in thin-films(DGT).Average concentrations of Cr,Ni,Cu,Zn,As,Cd and Pb in surface sediments were 31.25,30.31,22.00,45.04,31.32,0.13 and 13.39 mg/kg,respectively.Higher levels of metals were found near the inflowing rivers.Residual form was dominant in Cr,Ni,Zn,Cd and Pb,and reducible form was dominant in As and Cd.Metals in surface sediments showed a low enrichment degree overall,but Cd and As had higher ecological risk levels than the other metals.Furthermore,there was a larger average proportion of exchangeable form of As(20.4%)and Cd(9.0%)than the other metals(1.7%-3.3%),implying their higher mobility and release risk.Average DGT-labile concentrations of Cr,Ni,Cu,Zn,As,Cd and Pb were 0.5,4.5,0.7,25.1,60.0,0.22 and 1.0μg/L,respectively.The DGT-labile As was significantly correlated with extractable As forms(p<0.01),suggesting that extractable As in sediments acts as a"mobile pool"for bioavailable As.These results suggest potential risks of As and Cd,especially As,deserve further attention in Lake Yamdrok Basin.
基金sponsored by the National Natural Scientific Foundation of China (No. 41001334, 41001325)the Project of Knowledge Innovation for the 3rd period, the Chinese Academy of Sciences (No. KZCX2-YW-JS304)the Natural Scientific Foundation of Jiangsu Province, China (No. BK2010606)
文摘A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- （up to 106 g/L）, SO42- （up to 16 g/L）, HCO3- （up to 817 g/L）, and AsO2- and AsO 3 4 （both up to 1 mg As/L） in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH （4.2-9.2）. The lowest capacity （95 μg P/m2 at pH 9.2） was still greater than that of other DGT techniques that are usually used for the measurement of DRP （2-12 μg P/cm2 ）. The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices （6 months）. The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.
基金supported by National Natural Science Foundation of China(Nos.41503099,31971476)the CAS Interdisciplinary Innovation Team(No.JCTD-2018-16)the Key Research Program of Frontier Sciences,CAS(No.ZDBS-LYDQC018).
文摘Macrophytes are usually chosen for phytoremediation tools to remove P in eutrophic aquatic ecosystems,but the lack of test methods hinders the understanding of removal mechanism and application.In this study,we used the novel technologies combined of Diffusive gradients in thin films(DGT),Planar optode(PO),and Non-invasive micro-test technology(NMT)to explore P dynamics in water-sediment continuum and rhizosphere of Potamogeton crispus over time.Results of the high-resolution in situ measurement showed that labile P(LPDGT)fluxes at the surficial sediment significantly decreased from approximate 120,140,and 200 pg/(cm^(2)·sec)via 30 days incubation period to 17,40,and 56 pg/(cm2•sec)via that of 15 days.Obvious synchronous increase of LPDGT was not detected in overlying water,suggesting the intense assimilation of dissolve reactive P via root over time.PO measurement indicated that O_(2)concentration around the rhizosphere remarkably increased and radially diffused into deeper sediment until 100%saturation along with the root stretch downwards.NMT detection of roots showed the obvious O_(2)inflow into root tissue with the uppermost flux of 30 pmol/(cm2•sec)from surroundings via aerenchyma on different treatment conditions.Different from previous reports,gradually saturating O_(2)concentrations around the rhizosphere was principally driven by O_(2)penetration through interspace attributing to root stretch downward rather than root O_(2)leakage.Increased O_(2)concentrations in deep sediment over time finally induced the oxidization of labile Fe(II)into Fe(III)bound P and local P immobilization.
基金supported by the Mega-projects of Science Research for Water Environment Improvement (No. 2012ZX07101-002)the National Natural Science Foundation of China (No. 41303085)
文摘The technique of DGT（diffusive gradients in thin films） using three diffusive gel thicknesses was applied to estimate the mobility and bioavailability of heavy metals in sediments and porewater of Lake Taihu, China. The DGT results showed significantly positive correlations between Co, Pb, Cd and Mn, and Ni and Fe concentrations in porewater. Cu and Zn showed a significantly negative correlation with Mn, due to Cu combination with carbonates and Zn derived from agricultural pollution, respectively. The rank order of average concentrations of Co, Ni and Cd at each station was DGT1.92〉DGT0.78〉 DGT0.39, suggesting stronger resupply from sediments to porewater when using thicker diffusive gels. Comparing centrifugation and DGT measurements, Co, Ni and Cd are highly labile; Mn and Fe are moderately labile; and Cu, Zn and Pb are slightly labile. The variations of AVS concentrations in sediment cores indicate that metal sulfides in deeper layers are easily diffused into surface sediments.
基金supported by the China Postdoctoral Science Foundation (No. 2013M530783)the Research Foundation for Advanced Talents of Qingdao Agricultural University, China (No. 6631115029)
文摘A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass(Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT(CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt(Na2EDTA)- and acetic acid(HOAc)-extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perenne was negatively influenced by p H and positively influenced by organic matter(OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA- and HOAc-extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were p H and OM dependent. For CE, the relationship was p H independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability.
基金the Austrian Research Promotion Agency(FFG)through the Research Studio Austria FERTI-MINE(No.844744).
文摘Diffusive gradients in thin films(DGT)measurements have been shown to outperform other phosphorus(P)tests in soils with strong P sorption,but this has not been confirmed for moderately weathered European soils.We compared the performance of DGT in predicting wheat grain yield in Swedish long-term fertility experiments with those of standard intensity(water-extractable P(P-H2O))and quantity(ammonium lactate-extractable P(P-AL))tests.A Mitscherlich-type model was used to fit wheat yield response to P application rates(0,15,30 or 35,and 45 kg P ha-1 year-1)in each individual trial replicate to estimate the maximum yield.For trials with clear plateau-type yield responses and the goodness of fit(R2)>0.75,relative yields(RYs)were calculated for each P treatment and plotted against the soil P test results(n=143).The goodness of the Mitscherlich-type fits decreased in the following order:DGT-measured P(P-DGT)(R2=0.35)>P-H2O(R2=0.18)>P-AL(R2=0.13).When excluding soils with P-AL:P-DGT≥0.1 L g-1,R2 was considerably improved to 0.55 for P-AL,0.46 for P-H2O,and 0.65 for P-DGT(n=61).At 95%of maximum yield,the upper limit of P deficiency for P-DGT was 44.8(the soils with P-AL:P-DGT<0.1 L g-1)and 61.9μg L-1(all soils),falling within the range reported for other European and Australian soils(6.0–142μg L-1).We show that in the investigated Swedish soils,DGT performed better than the quantity and intensity tests,which is attributed to its ability to capture P diffusion and resupply from the soil solid phase,similar to plant roots in the rhizosphere.
基金A project supported by the China National Natural Science Foundation(No.49070079)
文摘On the basis of the detailed field work, compositions and contents of plagioclase and K - feldspar,determination of ordering degree, statistical analysis of plagioclase elongation index, mass-balance calculation and mineral spatial distribution and geochemistry, it is concluded that the migmatites in the Dabie complex are characterized by the presence of thermocenters. There are regular changes in mineral character in the migmatites from the centers outwards. The dominant genetic mechanism is anatexis and metasomatism, whose intensities decrease from the centers outwards. Finally, according to the simulated experiment on Liesegang' s rings and non-linear dynamics (dissipative structure theory), the dynamic mechanism of migmatization is profoundly expouded as consisting of the early-stage metasomatism induced by the thermal anomaly, the cardinal-stage anatexis induced by the early-stage matasomatism and finally the last-stage post-anatexis metasomatism.
基金We thank the financial support of National Natural Science Foundation of China(Grant No.21577010)Dalian Municipal Fund for High-level(Leading)Professionals(No.2015R011)Fundamental Research Funds for the Central Universities(No.DUT18LAB14).
文摘Urban wastewater is one of main sources for the introduction of antibiotics into the environment.Monitoring the concentrations of antibiotics in wastewater is necessary for estimating the amount of antibiotics discharged into the environment through urban wastewater treatment systems.In this study,we report a novel diffusive gradient in thin films(DGT)method based on molecularly imprinted polymers(MIPs)for in situ measurement of two typical antibiotics,fluoroquinolones(FQs)and sulfonamides(SAs)in urban wastewater.MIPs show specific adsorption toward their templates and their structural analogs,resulting in the selective uptake of the two target antibiotics during MIP-DGT deployment.The uptake performance of the MIP-DGTs was evaluated in the laboratory and was relatively independent of solution pH(4.0-9.0),ionic strength(1-750 mmol/L),and dissolved organic matter(DOM,0-20 mg/L).MIP-DGT samplers were tested in the effluent of an urban wastewater treatment plant for field trials,where three SA(sulfamethoxazole,sulfapyridine,and trimethoprim)and one FQ(ofloxacin)antibiotics were detected,with concentrations ranging from 25.50 to 117.58 ng/L,which are consistent with the results measured by grab sampling.The total removal efficiency of the antibiotics was 80.1%by the treatment plant.This study demonstrates that MIP-DGT is an effective tool for in situ monitoring of trace antibiotics in complex urban wastewaters.
基金financial support from the National Natural Science Foundation of China(U23A20481,62275010,62075004 and 62471021)the Beijing Natural Science Foundation(1232027)the Analysis&Testing Center in Beihang University,the Fundamental Research Funds for the Central Universities.
文摘Photoenergy harvesting is promising to power Internet-of-Things(IoT)sensors,freeing the limitations of wired power sources or batteries,enabling bio-integrated devices.However,existing photoenergy harvesting systems are restricted to solid or liquid configurations—limiting biocompatibility and space utilization—which makes obtaining flexible,biocompatible,light-harvesting devices a significant challenge.In this paper,inspired by natural ion gradient diffusion in organisms,offering an ion-hydrogel drops-based photoenergy harvesting base on ammonium molybdate.Through the photochemical process of ammonium molybdate,the electric potential of the device is regulated by the altered ion gradient and the redox pairs([Mo_(7)O_(24)]^(6-)/[Mo_(1)O_(46)]^(10-)),to generate energy.When exposed to excitation light,a photo driven ammonium molybdate-hydrogel photoenergy harvester(PAPH)can generate an open-circuit potential of~250 mV,and it can still obtain a considerable output power for milliseconds to thousands of seconds after the termination of the initial illumination.The reversible hydrogel droplets network allows for the recovery and fabrication of arbitrary structures of the PAPH.We further demonstrate the scalable PAPH networks can on-demand regulation of cell epithelial growth factor secretion and receptor expression,stimulate the cell proliferation,thereby facilitating biological tissue wound repair.This ionic hydrogel opens a new avenue for flexible,photoenergy harvesting,biocompatible devices.
