Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,...Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,amidoximebased radiation grafted adsorbents have been identified as effective for iron removal.In this study,an amidoximefunctionalized,radiation-grafted adsorbent synthesized from polypropylene waste(PPw-g-AO-10)was employed to remove iron from leached geological samples.The adsorption process was systematically optimized by investigating the effects of pH,contact time,adsorbent dosage,and initial ferric ion concentration.Under optimal conditions-pH1.4,a contact time of 90 min,and an initial ferric ion concentration of 4500 mg/L-the adsorbent exhibited a maximum iron adsorption capacity of 269.02 mg/g.After optimizing the critical adsorption parameters,the adsorbent was applied to the leached geological samples,achieving a 91%removal of the iron content.The adsorbent was regenerated through two consecutive cycles using 0.2 N HNO_(3),achieving a regeneration efficiency of 65%.These findings confirm the efficacy of the synthesized PPw-g-AO-10 as a cost-effective and eco-friendly adsorbent for successfully removing iron from leached geological matrices while maintaining a reasonable degree of reusability.展开更多
The thermodynamic analysis of the reaction between the main phase in magnesium slag and NH_(4)Cl solutions was carried out,and the ions leaching behaviors of Ca,Mg,Fe,and Al in magnesium slag under room temperature an...The thermodynamic analysis of the reaction between the main phase in magnesium slag and NH_(4)Cl solutions was carried out,and the ions leaching behaviors of Ca,Mg,Fe,and Al in magnesium slag under room temperature and microwave conditions were compared.Meanwhile,the effects of parameters on the leaching rate of Ca and Mg were investigated under the microwave heating conditions.The experimental results show that,in 273.15-373.15 K,Ca_(2)SiO_(4),CaSiO_(3),Ca_(2)Fe_(2)O_(5),and Mg_(2)SiO_(4)might react with NH_(4)Cl solution,while MgSiO_(3),MgO,Fe_(2)O_(3),and Al_(2)O_(3)are difficult to be leached.The leaching rates of Ca and Mg are 70.29%and 24.64%,respectively,when the conditions are 300 W of microwave power,1:20 of solid-liquid ratio,400 mL of 2 mol/L NH_(4)Cl solutions,and 90 min of leaching time.In addition,in the non-isothermal stage,the leaching process of Ca is changed from chemical reaction control to diffusion control,and the leaching rate of Ca gradually increases.However,the leaching process of Mg is always controlled by chemical reaction,and the leaching rate of Mg remains unchanged after the reaction reached equilibrium.展开更多
Cr leaching is anticipated to extensively advance the activity of Cr-containing catalysts towards the oxygen evolution reaction(OER),but the underlying catalytic enhancement mechanism requires further investigation.He...Cr leaching is anticipated to extensively advance the activity of Cr-containing catalysts towards the oxygen evolution reaction(OER),but the underlying catalytic enhancement mechanism requires further investigation.Herein,NiFeCr layered double hydroxide(NiFeCr-LDH)is proposed as a proof-of-concept catalyst to elucidate the evolution of Cr species and its enhancement mechanism in OER.The incorporation of Cr(Ⅲ)ions into the lattice of NiFe-LDH is achieved through a meticulously controlled electrodeposition process,which not only promotes Cr leaching but also deepens surface reconstruction.More importantly,experimental and theoretical results demonstrate that protogenetic CrO_(4)^(2-)anions,derived from the oxidation of leached Cr ions,adsorb onto the surface NiFeCr-LDH under the anodic potential to create a CrO_(4)^(2-)-rich electrical double layer(CrO_(4)^(2-)-rich EDL)and function as co-catalyst to trigger OER.CrO_(4)^(2-)-rich EDL integrated with vacancies balances the Gibbs free energies of the reconstructed NiFeCr-LDH for oxygen-containing intermediates,resulting in an exceptionally low overpotential of 286 mV at 500 mA cm^(−2),which outperforms most state-of-the-art metallic catalysts.Additionally,the anion exchange membrane water electrolysis system assembled with NiFeCr-LDH and Pt/C demonstrates 1000-h stability at a current density of 1.0 A cm^(−2)under a voltage of 1.74 V(at 70°C),highlighting its promising potential for practical,large-scale and sustainable applications.展开更多
Leached Pt-Fe and Pt-Co catalysts were prepared by acid leaching the reduced catalysts in acid solution. Oxidation treatments of leached catalysts produced the structure o f metal oxides decorat-ing the surface of...Leached Pt-Fe and Pt-Co catalysts were prepared by acid leaching the reduced catalysts in acid solution. Oxidation treatments of leached catalysts produced the structure o f metal oxides decorat-ing the surface of nanoparticles. The fully oxidized Fe2O3 and Co3O4 species on Pt nanoparticle sur-faces result in the low performance of the CO complete oxidation （COOX） reaction. In contrast, un-saturated FeO and CoO surface species can be formed during exposure to the CO preferential oxida-tion （CO-PROX） reaction with an excess of H2, leading to a high O2 activation ability and enhancing the CO-PROX activity. The FeOx surface structures can be transformed between these two states by varying the reactive gas environments, exhibiting oscillating activity in these two reactions. Con-versely, the CoO surface structure formed in the H2 -rich atmosphere is stable when exposed to the COOX reaction and exhibits similar activity in these two reactions. It is hoped that this work may assist in understanding the important role of surface oxides in real reactions.展开更多
Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil wa...Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil was flood-ed with penetration rate controlled at approxi-mate 3 mm per day in duration of double-riceseason and laid fallow and natural in winterand spring.Results showed that nitrate was the mainform of nitrogen in percolates.The change of展开更多
This paper compares the efficiency of D2EHPA and Cyanex 272 to extract the divalent manganese cation from an actual leaching solution obtained by reductive leaching of a low-grade pyrolusite ore, using SO2 gas. The st...This paper compares the efficiency of D2EHPA and Cyanex 272 to extract the divalent manganese cation from an actual leaching solution obtained by reductive leaching of a low-grade pyrolusite ore, using SO2 gas. The studied variables were the extractant concentration in the organic phase, the pH of the leached liquor and the volume ratio between organic phase and leached liquor. It was observed that D2EHPA is a better extractant than Cyanex272. Therefore, with the best experimental conditions found, both extractants reach a manganese recovery around 95% with five extraction stages conducted under the following conditions: 25?C, O/A = 2, 10% volume of extractant concentration in the organic phase, pH of the leached liquor before the mixing between 8 and 8.5, and one minute of mixing time for each extraction stage.展开更多
Aluminium(Al)foil can leach metals into fish during roasting,potentially creating health implications,which informed this study.The roasted(using Al foil)and unroasted fish(control)samples(n=48)were analysed for metal...Aluminium(Al)foil can leach metals into fish during roasting,potentially creating health implications,which informed this study.The roasted(using Al foil)and unroasted fish(control)samples(n=48)were analysed for metals(Al,Co,Pb,Ni,Cr,Cd,and As)using ICP-AES.The following ranges were recorded for Al(5.51-6.35 mg/kg),Co(0.25-0.35 mg/kg),Pb(0.48-0.65 mg/kg),Ni(2.37-4.70 mg/kg),Cr(0.25-0.43 mg/kg),Cd(0.05-0.07 mg/kg),As(0.32-0.45 mg/kg).According to redundancy analysis,foil area had the most influence on metal leaching.The percentage weight loss of the foil after fish roasting indicates leaching of its metal contents into the fish.The EDI and THQ of As,and HI of metals indicate potential risk over time,as a result,roasting of fish with foil should be discontinued.展开更多
NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsi...NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsic activity limitations and poor stability,primarily due to the asymmetric adsorption of oxygen intermediates.To overcome this,the binding strength must be synergistically tuned to a moderate level to optimize catalytic performance.Here,we engineered NiFeCoCr LDH through Co doping to enhance electrical conductivity and controlled Cr leaching to introduce cationic vacancies for modulating intermediate binding strength in NiFe LDH.X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses reveal that NiFe-LDH with Co doping and Cr vacancies modulates the Ni oxidation state and local coordination environment,leading to a balanced electronic structure and enhanced structural complexity around the Ni sites.Additionally,these vacancies can trap OH^(-)/H_(2)O species,which can serve as a reservoir for OH^(-) transfer,facilitating the rapid formation of OER intermediates and enhancing catalytic performance at high current densities.As a result,V_(Cr)-NiFeCo LDH achieves 1.6 A cm^(-2)current density at 1.7 V vs.RHE while maintaining stable operation for over 1000 h at 500 mA cm^(-2).Density functional theory(DFT)calculations validate the synergistic effects of Co doping and Cr-induced vacancies on intermediate binding energies and improved OER kinetics.Overall,this work presents a rational design strategy to simultaneously enhance the activity and durability of NiFe-based OER catalysts for their application in high-performance alkaline water electrolysis.展开更多
The efficient extraction and separation of valuable metal elements from coal gasification fine slag(CGFS)are crucial for the comprehensive high-value utilization of its constituents.This study focused on the carbon-ri...The efficient extraction and separation of valuable metal elements from coal gasification fine slag(CGFS)are crucial for the comprehensive high-value utilization of its constituents.This study focused on the carbon-rich components of CGFS(CGFS-H)and systematically investigates the selective leaching behavior of Fe^(3+),Al^(3+)and Ca^(2+)using three organic acid extractants,i.e.,citric acid,tartaric acid,and tetrasodium iminodisuccinate.Additionally,the stepwise leaching of iron,aluminum and calcium from CGFS-H is explored.The selective dissolution mechanisms of these metals by different organic acids are elucidated through X-ray diffraction(XRD),X-ray fluorescence(XRF),and scanning electron microscopy(SEM)analyses.The results indicate that tetrasodium iminodisuccinate exhibits the highest leaching selectivity for Fe^(3+),while tartaric acid demonstrateds a comparable affinity for both Fe^(3+)and Al^(3+).In contrast citric acid shows superior selectivity toward Ca^(2+).The leaching yield of Fe^(3+),Al^(3+)and Ca^(2+)after sequential leaching with the three organic acids were 79.8%,65.08%and 78.6%,respectively.These findings confirm that effective and selective separation of Fe^(3+),Al^(3+)and Ca^(2+)from CGFS-H can be achieved via optimized organic acid-based leaching strategies.This advancement provides a critical foundation for developing Ca/Fe/Al hydrotalcite materials using CGFS-H as a sustainable feedstock,thereby facilitating the transformation of waste residue into high-value functional materials and promoting resourceefficient utilization of coal gasification fine slag.展开更多
Phosphogypsum,an industrial solid waste,is an effective binder for partially replacing cement in stabilizing dredged sediments.Acid rain,as a worldwide ecological problem,also affects the long-term stability and susta...Phosphogypsum,an industrial solid waste,is an effective binder for partially replacing cement in stabilizing dredged sediments.Acid rain,as a worldwide ecological problem,also affects the long-term stability and sustainability of geotechnical materials and structures.However,the research on leaching effects and long-term durability of phosphogypsum-stabilized soils under acid rain conditions is limited and remains a significant challenge for practical applications.This study investigates the leaching effects and long-term durability of phosphogypsum-stabilized soils by simulating acid rain erosion through semi-dynamic leaching tests.Key parameters,including leached Ca^(2+)concentration,leachate pH,and unconfined compressive strength after leaching,were evaluated.Microscopic analyses with X-ray diffraction(XRD)and scanning electron microscopy(SEM)were also conducted to explore the underlying mechanisms.The results indicate that the presence of phosphogypsum in stabilized soil with high water content shows a significant improvement in leaching resistance subjected to acid ions,evidencing a lower Ca^(2+)concentration and pH value in the leachate,and a higher strength after leaching compared to those samples without phosphogypsum.SEM images and XRD analysis revealed that samples with higher phosphogypsum content possess denser structures due to more needle-shaped ettringite and other minerals in the soil matrix,contributing to improved strength and leaching resistance.The enhanced strength and leaching resistance of phosphogypsum-stabilized soil can be attributed to additional gel formation,a rise in swelling potential,ettringite bridging,and a denser microstructure,which reduces Ca^(2+)availability for leaching in acidic environments.展开更多
The leaching mechanism of gallium(Ga)and germanium(Ge)from zinc powder replacement residue(ZPRR)was investigated through ultrasonic-assisted sulfuric acid leaching.Characterization via XRD,SEM,XPS,and FT-IR revealed t...The leaching mechanism of gallium(Ga)and germanium(Ge)from zinc powder replacement residue(ZPRR)was investigated through ultrasonic-assisted sulfuric acid leaching.Characterization via XRD,SEM,XPS,and FT-IR revealed that ultrasonic treatment promotes the dehydration of H_(4)SiO_(4)colloids,thereby reducing their adsorption capacities for Ga and Ge complexes.Additionally,ultrasound enhances the dissolution of CaS in H_(2)SO_(4),increasing H_(2)S production,which aids in the reduction of Fe^(3+)and mitigates iron precipitate formation.Process parameters including ultrasonic power(0-450 W),temperature(100-120℃),and leaching time(30-120 min)were systematically optimized,achieving optimal leaching efficiencies of Ga and Ge at 95.7%and 94.5%,respectively.展开更多
Extracting rare earth elements(REEs)from coal refuse is challenging due to their low co ncentrations and poor leachability.Bioleaching has emerged as a sustainable technology to recover REEs from low-grade materials.I...Extracting rare earth elements(REEs)from coal refuse is challenging due to their low co ncentrations and poor leachability.Bioleaching has emerged as a sustainable technology to recover REEs from low-grade materials.In this study,a ferric sulfate bio acid(BA)with an acidity of~0.2 mol/L H^(+),generated through regulated pyrite bio-oxidation,was used to leach REEs and critical metals(CMs)from coal refuse(ground to<1 mm)after 20-min roasting at 600℃.The influences of solid/liquid(S/L)ratio(100-300 g/L)and leaching temperature(25-95℃)on the leaching performance were examined.The leaching mechanisms were investigated by conducting stepwise precipitation tests and spectroscopic characterization.Results show that raising the leaching temperature to≥65℃accelerated the REE leaching kinetics but causes the loss of light REEs(LREEs)after reaching peak values at 30-60 min.Stage precipitation tests reveal that the loss is due to the incorporation of REEs,especially for LREEs,by gypsum and schwertmannite.The peak total REE(TREE)recovery of the BA leaching reaches 24.9%after 30 min of leaching at75℃with a S/L ratio of 200 g/L.Implementing the three-stage counter-current leaching increases the overall TREE recovery to 31.8%by recovering the REEs incorporated in the Fe and Ca precipitates.Meanwhile,promising recovery values of Li(55.5%),Mn(74.6%),Ni(41.6%),and Co(35.3%)are also achieved.This method provides a sustainable approach to extract REEs and critical metals from coal waste materials with a high treatment capacity.展开更多
China has limited acaricide options for tea plantations.Cyetpyrafen,a novel domestic acaricide with high efficacy,low toxicity and a negative temperature coefficient,offers an alternative for tea pest control;however,...China has limited acaricide options for tea plantations.Cyetpyrafen,a novel domestic acaricide with high efficacy,low toxicity and a negative temperature coefficient,offers an alternative for tea pest control;however,its residue fate in tea remains unclear.This study developed a method to simultaneously detect cyetpyrafen and its metabolites(M-309,M-325-1,and M-409-3)in different tea matrices to investigate their fate.Recoveries of compounds ranged from 73.4 to 106.2%with the relative standard deviations(RSDs)below 12.0%.During tea cultivation,the dissipation half-life of cyetpyrafen was 0.59 d,with M-309 as a major metabolite.The residues of cyetpyrafen and M-309 were affected by different processing stages,especially water loss and high temperatures during fixing,drying and withering.The total processing factors ranged from 1.39 to 1.71 for green tea and 1.48 to 2.28 for black tea(processed from fresh tea leaves sampled at 1,5,and 7 d),respectively.The leaching rates of cyetpyrafen from green tea and black tea into tea infusions were 7.4 and 6%,respectively.The risk associated with cyetpyrafen intake from tea consumption was low,with risk quotient values below 100%.However,theoretical calculation indicated potential harm to non-target organisms from its metabolites.This research provides a reference for the safe and efficient use of cyetpyrafen in tea gardens.展开更多
The leaching process and kinetic behavior of lepidolite in hydrochloric acid were explored systematically.The influence of leaching conditions on the leaching efficiency of valuable metals in lepidolite was investigat...The leaching process and kinetic behavior of lepidolite in hydrochloric acid were explored systematically.The influence of leaching conditions on the leaching efficiency of valuable metals in lepidolite was investigated.Under optimized conditions,the leaching efficiencies of Li,K,Rb,Cs and Al are 92.02%,93.31%,88.59%,86.75%and 81.07%,respectively.Kinetics research results show that the leaching process conforms to the shrinking core model that is under the mixed control of chemical reaction and diffusion through the solid product layer.In addition,the contribution of solid product layer diffusion to the leaching gradually expands as the temperature rises,but it is still significantly less than the contribution of chemical reaction.Cost saving in the neutralizing agent and leaching processes makes hydrochloric acid an economical leaching agent for lepidolite.Finally,the Li2CO3 product with a purity of 99.89%was synthesized from the hydrochloric acid leachate.展开更多
Herbicides are indispensable for safeguarding global crop production,yet their effectiveness is often undermined by extensive environmental losses during application.Using herbicide Diuron as a model compound,we devel...Herbicides are indispensable for safeguarding global crop production,yet their effectiveness is often undermined by extensive environmental losses during application.Using herbicide Diuron as a model compound,we developed hierarchical nanoparticles constructed through host-vip molecular recognition followed by electrostatic coassembly,yielding a formulation that unites high delivery efficiency with enhanced environmental compatibility.Relative to conventional wettable powders,these nanoparticles exhibited temperature-responsive release behavior and significantly enhanced foliar adhesion and deposition,increasing leaf retention by more than 241.7%.They also demonstrated strong resistance to rainfall wash-off and a markedly reduced propensity for groundwater leaching,with leaching losses decreased by approximately 18.6%.Greenhouse and field evaluations further confirmed their superior weed control under practical conditions,achieving control efficacies of up to 70.1%against Abutilon theophrasti and 52.9%against Setaria faberi,compared with 53.7%and 39.1%,respectively,for the commercial formulation at the same application rate.Extensive ecotoxicological assessments encompassing seed germination,zebrafish and earthworm assays,in vitro cellular tests,and in vivo rat studies consistently revealed an improved safety profile compared with commercial and technical formulations.Together,these results highlight hierarchical self-assembled nanoparticles as a promising platform for next-generation herbicide delivery that combines high target utilization with lower environmental impact and greater sustainability.展开更多
Acid is commonly used to separate phosphorus-containing solid solutions from steelmaking slag.However,the acid leaching solution obtained from this process cannot be directly utilized and thus requires purification.Th...Acid is commonly used to separate phosphorus-containing solid solutions from steelmaking slag.However,the acid leaching solution obtained from this process cannot be directly utilized and thus requires purification.The effect of different conditions on the calcium and iron removal characteristics of modified steelmaking slag leaching solution was investigated.Additionally,the removal mechanism was analyzed by thermodynamic calculations.The results indicated that the addition of soybean straw ash in steelmaking slag modification enabled K_(2)O to enter the phosphorus-containing solid solution,promoting phosphorus enrichment.Valuable elements such as phosphorus and potassium were more easily dissolved in the mixed acid.The oxalic acid concentration had a significant effect on the calcium removal rate,whereas the effects of temperature,stirring rate,and time on the calcium removal rate were minor.The main component of the calcium removal precipitate was CaC_(2)O_(4)·H_(2)O,with a removal rate up to 94.48%.During the iron removal process,when the pH value of the solution was low,Fe^(3+)mainly reacted to form the iron hydroxide precipitate for removal.Increasing the pH value of the solution would cause Fe^(3+)to combine with H_(2)PO_(4)^(-),forming FePO_(4)·2H_(2)O precipitate,leading to a reduction in the phosphorus content of the leaching solution.展开更多
The insufficient performance of Pt and Pd benchmark catalysts remains a significant obstacle to the practical application of direct liquid fuel cells.In this study,we report a synthesis of amorphous PdSe/crystalline P...The insufficient performance of Pt and Pd benchmark catalysts remains a significant obstacle to the practical application of direct liquid fuel cells.In this study,we report a synthesis of amorphous PdSe/crystalline Pt nanoparticles(AC-PdPtSe NPs)by chemical leaching of PdPtSe NPs.AC-PdPtSe NPs display significantly enhanced activity and stability for the electrooxidation of ethylene glycol and glycerol,far surpassing that of amorphous-dominant PdPtSe NPs,commercial Pd/C,and Pt/C catalysts.Notably,the integration of crystalline and amorphous domains leverages the advantages of high electrical conductivity and a wealth of active sites,which can substantially accelerate reaction kinetics.Furthermore,detailed investigations reveal that the boundary between the Pt crystalline and PdSe amorphous phases induces a 3%surface tensile strain.The formation of amorphous-crystalline heterointerfaces optimizes the d-band states,thereby strengthening the adsorption and activation of ethylene glycol and glycerol.This study highlights the advance in phase engineering toward the development of highly active noble-metal nanostructures.展开更多
In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics...In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.展开更多
Phosphorus(P)leaching in alkaline soils,exacerbated by excessive fertilizer application,represents a significant pathway for P loss.While soil pore structure and texture critically regulate P transport,mechanisms gove...Phosphorus(P)leaching in alkaline soils,exacerbated by excessive fertilizer application,represents a significant pathway for P loss.While soil pore structure and texture critically regulate P transport,mechanisms governing P loss in texturally diverse alkaline soils remain unclear.This study investigated P leaching dynamics and transport parameters across four alkaline soil textures(silty clay,clay loam,loam,sandy loam)using a one-dimensional convective-diffusion equation(CDE)based on column experiments.Results indicated that phosphorus leaching kinetics were predominantly governed by diffusion transport,evidenced by low Peclet numbers(P_(e))(ranged from 0.02 to 0.31)across varying textures and initial P concentrations(C_(0)).Comparative analysis of transport parameters revealed significant textural effects on dispersion coefficient(D),retardation factor(R),pore water velocity(V),P_(e),and diffusion coefficient(λ)(F>523.42,p<0.001).Among these,only D,P_(e) andλexhibited substantial differences in response to variations in C_(0)(F>89.47,p<0.001).Saturated hydraulic conductivity(K_(s))(R^(2)=62.9%,p<0.01)and total pore area(A)(R^(2)=12.4%,p<0.01)emerged as primary regulators of P leaching.Enhanced clay content increased total pore area while reducing average pore diameter,concurrently decreasing pore water velocity and saturated infiltration rates.These textural modifications amplified diffusive P transport within soil matrices.The findings provide mechanistic insights into texturedependent P mobility in alkaline environments,informing targeted strategies for agricultural phosphorus management.展开更多
Heavy metal contamination of soil is one of the major challenges to sustainable agriculture.This contamination can be transmitted through the soil food chain and poses a serious threat to human health.In this study,we...Heavy metal contamination of soil is one of the major challenges to sustainable agriculture.This contamination can be transmitted through the soil food chain and poses a serious threat to human health.In this study,we found that freeze-thaw leaching(FTL)effectively complements the low removal rate of chemical leaching,and investigated the effects of different numbers of FTL on Cd contamination,soil chemical properties and microbial communities.The results showed that repeated FTL significantly reduced(P<0.05)the total Cd content in the top soil(19.02%-49.35%)and subsoil(0.41%-21.13%)and promoted the transformation of Cd to a more stable form,mainly through various removal mechanisms such as complexation,ion-exchange,and chemical precipitation.This finding was supported by reductions in several soil properties,including pH,available potassium(AK),and available phosphorus(AP).FTL treatment initially increased the bioavailability of Cd compared to chemical leaching,but bioavailability of Cd progressively decreased as the number of freeze-thaw cycles increased.Additionally,FTL reduced the richness and diversity of bacteria communities,destabilized ecological symbiotic networks,while increasing the richness and diversity of fungi in the soil.Various model analyses indicated that FTL treatment,available Cd,soil pH,AP and AK were the key drivers influencing the changes in microbial community structure.This study provides new insights and scientific bases for the effective management of heavy metal pollution in agricultural soils,the restoration of ecosystem health,and the improvement of soil sustainability.展开更多
文摘Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,amidoximebased radiation grafted adsorbents have been identified as effective for iron removal.In this study,an amidoximefunctionalized,radiation-grafted adsorbent synthesized from polypropylene waste(PPw-g-AO-10)was employed to remove iron from leached geological samples.The adsorption process was systematically optimized by investigating the effects of pH,contact time,adsorbent dosage,and initial ferric ion concentration.Under optimal conditions-pH1.4,a contact time of 90 min,and an initial ferric ion concentration of 4500 mg/L-the adsorbent exhibited a maximum iron adsorption capacity of 269.02 mg/g.After optimizing the critical adsorption parameters,the adsorbent was applied to the leached geological samples,achieving a 91%removal of the iron content.The adsorbent was regenerated through two consecutive cycles using 0.2 N HNO_(3),achieving a regeneration efficiency of 65%.These findings confirm the efficacy of the synthesized PPw-g-AO-10 as a cost-effective and eco-friendly adsorbent for successfully removing iron from leached geological matrices while maintaining a reasonable degree of reusability.
基金Funded by the National Key Research and Development Program of China(No.2023YFC2908002)。
文摘The thermodynamic analysis of the reaction between the main phase in magnesium slag and NH_(4)Cl solutions was carried out,and the ions leaching behaviors of Ca,Mg,Fe,and Al in magnesium slag under room temperature and microwave conditions were compared.Meanwhile,the effects of parameters on the leaching rate of Ca and Mg were investigated under the microwave heating conditions.The experimental results show that,in 273.15-373.15 K,Ca_(2)SiO_(4),CaSiO_(3),Ca_(2)Fe_(2)O_(5),and Mg_(2)SiO_(4)might react with NH_(4)Cl solution,while MgSiO_(3),MgO,Fe_(2)O_(3),and Al_(2)O_(3)are difficult to be leached.The leaching rates of Ca and Mg are 70.29%and 24.64%,respectively,when the conditions are 300 W of microwave power,1:20 of solid-liquid ratio,400 mL of 2 mol/L NH_(4)Cl solutions,and 90 min of leaching time.In addition,in the non-isothermal stage,the leaching process of Ca is changed from chemical reaction control to diffusion control,and the leaching rate of Ca gradually increases.However,the leaching process of Mg is always controlled by chemical reaction,and the leaching rate of Mg remains unchanged after the reaction reached equilibrium.
基金the support of this research by the National Key Research and Development Program of China(2024YFB4106400)the National Natural Science Foundation of China(22179035)the Science Fund for Distinguished Young Scholars of Heilongjiang Province(JQ2022B001)。
文摘Cr leaching is anticipated to extensively advance the activity of Cr-containing catalysts towards the oxygen evolution reaction(OER),but the underlying catalytic enhancement mechanism requires further investigation.Herein,NiFeCr layered double hydroxide(NiFeCr-LDH)is proposed as a proof-of-concept catalyst to elucidate the evolution of Cr species and its enhancement mechanism in OER.The incorporation of Cr(Ⅲ)ions into the lattice of NiFe-LDH is achieved through a meticulously controlled electrodeposition process,which not only promotes Cr leaching but also deepens surface reconstruction.More importantly,experimental and theoretical results demonstrate that protogenetic CrO_(4)^(2-)anions,derived from the oxidation of leached Cr ions,adsorb onto the surface NiFeCr-LDH under the anodic potential to create a CrO_(4)^(2-)-rich electrical double layer(CrO_(4)^(2-)-rich EDL)and function as co-catalyst to trigger OER.CrO_(4)^(2-)-rich EDL integrated with vacancies balances the Gibbs free energies of the reconstructed NiFeCr-LDH for oxygen-containing intermediates,resulting in an exceptionally low overpotential of 286 mV at 500 mA cm^(−2),which outperforms most state-of-the-art metallic catalysts.Additionally,the anion exchange membrane water electrolysis system assembled with NiFeCr-LDH and Pt/C demonstrates 1000-h stability at a current density of 1.0 A cm^(−2)under a voltage of 1.74 V(at 70°C),highlighting its promising potential for practical,large-scale and sustainable applications.
基金supported by the National Natural Science Foundation of China(21403004,21403003)~~
文摘Leached Pt-Fe and Pt-Co catalysts were prepared by acid leaching the reduced catalysts in acid solution. Oxidation treatments of leached catalysts produced the structure o f metal oxides decorat-ing the surface of nanoparticles. The fully oxidized Fe2O3 and Co3O4 species on Pt nanoparticle sur-faces result in the low performance of the CO complete oxidation （COOX） reaction. In contrast, un-saturated FeO and CoO surface species can be formed during exposure to the CO preferential oxida-tion （CO-PROX） reaction with an excess of H2, leading to a high O2 activation ability and enhancing the CO-PROX activity. The FeOx surface structures can be transformed between these two states by varying the reactive gas environments, exhibiting oscillating activity in these two reactions. Con-versely, the CoO surface structure formed in the H2 -rich atmosphere is stable when exposed to the COOX reaction and exhibits similar activity in these two reactions. It is hoped that this work may assist in understanding the important role of surface oxides in real reactions.
文摘Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil was flood-ed with penetration rate controlled at approxi-mate 3 mm per day in duration of double-riceseason and laid fallow and natural in winterand spring.Results showed that nitrate was the mainform of nitrogen in percolates.The change of
文摘This paper compares the efficiency of D2EHPA and Cyanex 272 to extract the divalent manganese cation from an actual leaching solution obtained by reductive leaching of a low-grade pyrolusite ore, using SO2 gas. The studied variables were the extractant concentration in the organic phase, the pH of the leached liquor and the volume ratio between organic phase and leached liquor. It was observed that D2EHPA is a better extractant than Cyanex272. Therefore, with the best experimental conditions found, both extractants reach a manganese recovery around 95% with five extraction stages conducted under the following conditions: 25?C, O/A = 2, 10% volume of extractant concentration in the organic phase, pH of the leached liquor before the mixing between 8 and 8.5, and one minute of mixing time for each extraction stage.
基金IHE Delft(the Netherlands)for providing infrastructural support and staff time to collaborate with researchers from Nigeria and China through the project"Support to Society".
文摘Aluminium(Al)foil can leach metals into fish during roasting,potentially creating health implications,which informed this study.The roasted(using Al foil)and unroasted fish(control)samples(n=48)were analysed for metals(Al,Co,Pb,Ni,Cr,Cd,and As)using ICP-AES.The following ranges were recorded for Al(5.51-6.35 mg/kg),Co(0.25-0.35 mg/kg),Pb(0.48-0.65 mg/kg),Ni(2.37-4.70 mg/kg),Cr(0.25-0.43 mg/kg),Cd(0.05-0.07 mg/kg),As(0.32-0.45 mg/kg).According to redundancy analysis,foil area had the most influence on metal leaching.The percentage weight loss of the foil after fish roasting indicates leaching of its metal contents into the fish.The EDI and THQ of As,and HI of metals indicate potential risk over time,as a result,roasting of fish with foil should be discontinued.
基金supported by the Natural Science Foundation of China Grant No.52272289 and 5240223,and JSPS(Japan Society for the Promotion of Science)of Grant No.22K19088,23H00313,24H02202,and 24H02205。
文摘NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsic activity limitations and poor stability,primarily due to the asymmetric adsorption of oxygen intermediates.To overcome this,the binding strength must be synergistically tuned to a moderate level to optimize catalytic performance.Here,we engineered NiFeCoCr LDH through Co doping to enhance electrical conductivity and controlled Cr leaching to introduce cationic vacancies for modulating intermediate binding strength in NiFe LDH.X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses reveal that NiFe-LDH with Co doping and Cr vacancies modulates the Ni oxidation state and local coordination environment,leading to a balanced electronic structure and enhanced structural complexity around the Ni sites.Additionally,these vacancies can trap OH^(-)/H_(2)O species,which can serve as a reservoir for OH^(-) transfer,facilitating the rapid formation of OER intermediates and enhancing catalytic performance at high current densities.As a result,V_(Cr)-NiFeCo LDH achieves 1.6 A cm^(-2)current density at 1.7 V vs.RHE while maintaining stable operation for over 1000 h at 500 mA cm^(-2).Density functional theory(DFT)calculations validate the synergistic effects of Co doping and Cr-induced vacancies on intermediate binding energies and improved OER kinetics.Overall,this work presents a rational design strategy to simultaneously enhance the activity and durability of NiFe-based OER catalysts for their application in high-performance alkaline water electrolysis.
基金Supported by National Natural Science Foundation(52374279)。
文摘The efficient extraction and separation of valuable metal elements from coal gasification fine slag(CGFS)are crucial for the comprehensive high-value utilization of its constituents.This study focused on the carbon-rich components of CGFS(CGFS-H)and systematically investigates the selective leaching behavior of Fe^(3+),Al^(3+)and Ca^(2+)using three organic acid extractants,i.e.,citric acid,tartaric acid,and tetrasodium iminodisuccinate.Additionally,the stepwise leaching of iron,aluminum and calcium from CGFS-H is explored.The selective dissolution mechanisms of these metals by different organic acids are elucidated through X-ray diffraction(XRD),X-ray fluorescence(XRF),and scanning electron microscopy(SEM)analyses.The results indicate that tetrasodium iminodisuccinate exhibits the highest leaching selectivity for Fe^(3+),while tartaric acid demonstrateds a comparable affinity for both Fe^(3+)and Al^(3+).In contrast citric acid shows superior selectivity toward Ca^(2+).The leaching yield of Fe^(3+),Al^(3+)and Ca^(2+)after sequential leaching with the three organic acids were 79.8%,65.08%and 78.6%,respectively.These findings confirm that effective and selective separation of Fe^(3+),Al^(3+)and Ca^(2+)from CGFS-H can be achieved via optimized organic acid-based leaching strategies.This advancement provides a critical foundation for developing Ca/Fe/Al hydrotalcite materials using CGFS-H as a sustainable feedstock,thereby facilitating the transformation of waste residue into high-value functional materials and promoting resourceefficient utilization of coal gasification fine slag.
基金supported by the National Natural Science Foundation of China(Grant Nos.52178361,52178328,and 42377190).
文摘Phosphogypsum,an industrial solid waste,is an effective binder for partially replacing cement in stabilizing dredged sediments.Acid rain,as a worldwide ecological problem,also affects the long-term stability and sustainability of geotechnical materials and structures.However,the research on leaching effects and long-term durability of phosphogypsum-stabilized soils under acid rain conditions is limited and remains a significant challenge for practical applications.This study investigates the leaching effects and long-term durability of phosphogypsum-stabilized soils by simulating acid rain erosion through semi-dynamic leaching tests.Key parameters,including leached Ca^(2+)concentration,leachate pH,and unconfined compressive strength after leaching,were evaluated.Microscopic analyses with X-ray diffraction(XRD)and scanning electron microscopy(SEM)were also conducted to explore the underlying mechanisms.The results indicate that the presence of phosphogypsum in stabilized soil with high water content shows a significant improvement in leaching resistance subjected to acid ions,evidencing a lower Ca^(2+)concentration and pH value in the leachate,and a higher strength after leaching compared to those samples without phosphogypsum.SEM images and XRD analysis revealed that samples with higher phosphogypsum content possess denser structures due to more needle-shaped ettringite and other minerals in the soil matrix,contributing to improved strength and leaching resistance.The enhanced strength and leaching resistance of phosphogypsum-stabilized soil can be attributed to additional gel formation,a rise in swelling potential,ettringite bridging,and a denser microstructure,which reduces Ca^(2+)availability for leaching in acidic environments.
基金financially supported by the National Key Research and Development Program of China(No.2022YFC2904900)the National Natural Science Foundation of China(Nos.52204392,52274385,52204347)the Young Elite Scientists Sponsorship Program by CAST,China(No.2022QNRC001)。
文摘The leaching mechanism of gallium(Ga)and germanium(Ge)from zinc powder replacement residue(ZPRR)was investigated through ultrasonic-assisted sulfuric acid leaching.Characterization via XRD,SEM,XPS,and FT-IR revealed that ultrasonic treatment promotes the dehydration of H_(4)SiO_(4)colloids,thereby reducing their adsorption capacities for Ga and Ge complexes.Additionally,ultrasound enhances the dissolution of CaS in H_(2)SO_(4),increasing H_(2)S production,which aids in the reduction of Fe^(3+)and mitigates iron precipitate formation.Process parameters including ultrasonic power(0-450 W),temperature(100-120℃),and leaching time(30-120 min)were systematically optimized,achieving optimal leaching efficiencies of Ga and Ge at 95.7%and 94.5%,respectively.
文摘Extracting rare earth elements(REEs)from coal refuse is challenging due to their low co ncentrations and poor leachability.Bioleaching has emerged as a sustainable technology to recover REEs from low-grade materials.In this study,a ferric sulfate bio acid(BA)with an acidity of~0.2 mol/L H^(+),generated through regulated pyrite bio-oxidation,was used to leach REEs and critical metals(CMs)from coal refuse(ground to<1 mm)after 20-min roasting at 600℃.The influences of solid/liquid(S/L)ratio(100-300 g/L)and leaching temperature(25-95℃)on the leaching performance were examined.The leaching mechanisms were investigated by conducting stepwise precipitation tests and spectroscopic characterization.Results show that raising the leaching temperature to≥65℃accelerated the REE leaching kinetics but causes the loss of light REEs(LREEs)after reaching peak values at 30-60 min.Stage precipitation tests reveal that the loss is due to the incorporation of REEs,especially for LREEs,by gypsum and schwertmannite.The peak total REE(TREE)recovery of the BA leaching reaches 24.9%after 30 min of leaching at75℃with a S/L ratio of 200 g/L.Implementing the three-stage counter-current leaching increases the overall TREE recovery to 31.8%by recovering the REEs incorporated in the Fe and Ca precipitates.Meanwhile,promising recovery values of Li(55.5%),Mn(74.6%),Ni(41.6%),and Co(35.3%)are also achieved.This method provides a sustainable approach to extract REEs and critical metals from coal waste materials with a high treatment capacity.
基金financially supported by the National Key Research and Development Program of China(2022YFD1600803)the National Natural Science Foundation of China(31772077)+1 种基金the Yunnan Provincial Tea Industry Technology Innovation Center,China(202505AK340010)the Chinese Academy of Agricultural Sciences for Agricultural Science and Technology Innovation Program of Tea Research Institute(CAAS-ASTIP-2021-TRI)。
文摘China has limited acaricide options for tea plantations.Cyetpyrafen,a novel domestic acaricide with high efficacy,low toxicity and a negative temperature coefficient,offers an alternative for tea pest control;however,its residue fate in tea remains unclear.This study developed a method to simultaneously detect cyetpyrafen and its metabolites(M-309,M-325-1,and M-409-3)in different tea matrices to investigate their fate.Recoveries of compounds ranged from 73.4 to 106.2%with the relative standard deviations(RSDs)below 12.0%.During tea cultivation,the dissipation half-life of cyetpyrafen was 0.59 d,with M-309 as a major metabolite.The residues of cyetpyrafen and M-309 were affected by different processing stages,especially water loss and high temperatures during fixing,drying and withering.The total processing factors ranged from 1.39 to 1.71 for green tea and 1.48 to 2.28 for black tea(processed from fresh tea leaves sampled at 1,5,and 7 d),respectively.The leaching rates of cyetpyrafen from green tea and black tea into tea infusions were 7.4 and 6%,respectively.The risk associated with cyetpyrafen intake from tea consumption was low,with risk quotient values below 100%.However,theoretical calculation indicated potential harm to non-target organisms from its metabolites.This research provides a reference for the safe and efficient use of cyetpyrafen in tea gardens.
基金supported by the National Natural Science Foundation of China(No.52122407)the National Key Research&Development Program of China(No.2022YF2906200)the Science and Technology Innovation Program of Hunan Province,China(No.2022RC3048)。
文摘The leaching process and kinetic behavior of lepidolite in hydrochloric acid were explored systematically.The influence of leaching conditions on the leaching efficiency of valuable metals in lepidolite was investigated.Under optimized conditions,the leaching efficiencies of Li,K,Rb,Cs and Al are 92.02%,93.31%,88.59%,86.75%and 81.07%,respectively.Kinetics research results show that the leaching process conforms to the shrinking core model that is under the mixed control of chemical reaction and diffusion through the solid product layer.In addition,the contribution of solid product layer diffusion to the leaching gradually expands as the temperature rises,but it is still significantly less than the contribution of chemical reaction.Cost saving in the neutralizing agent and leaching processes makes hydrochloric acid an economical leaching agent for lepidolite.Finally,the Li2CO3 product with a purity of 99.89%was synthesized from the hydrochloric acid leachate.
基金supported by the University Synergy Innovation Program of Anhui Province(GXXT-2021-059)the National Key Research and Development Program of China(2023YFD1702102)the Major Natural Science Research Project of Anhui Universities(2023AH040143).
文摘Herbicides are indispensable for safeguarding global crop production,yet their effectiveness is often undermined by extensive environmental losses during application.Using herbicide Diuron as a model compound,we developed hierarchical nanoparticles constructed through host-vip molecular recognition followed by electrostatic coassembly,yielding a formulation that unites high delivery efficiency with enhanced environmental compatibility.Relative to conventional wettable powders,these nanoparticles exhibited temperature-responsive release behavior and significantly enhanced foliar adhesion and deposition,increasing leaf retention by more than 241.7%.They also demonstrated strong resistance to rainfall wash-off and a markedly reduced propensity for groundwater leaching,with leaching losses decreased by approximately 18.6%.Greenhouse and field evaluations further confirmed their superior weed control under practical conditions,achieving control efficacies of up to 70.1%against Abutilon theophrasti and 52.9%against Setaria faberi,compared with 53.7%and 39.1%,respectively,for the commercial formulation at the same application rate.Extensive ecotoxicological assessments encompassing seed germination,zebrafish and earthworm assays,in vitro cellular tests,and in vivo rat studies consistently revealed an improved safety profile compared with commercial and technical formulations.Together,these results highlight hierarchical self-assembled nanoparticles as a promising platform for next-generation herbicide delivery that combines high target utilization with lower environmental impact and greater sustainability.
基金supported by the National Natural Science Foundation of China(52074004 and 51604003)Anhui Provincial Natural Science Foundation(2508085Y032).
文摘Acid is commonly used to separate phosphorus-containing solid solutions from steelmaking slag.However,the acid leaching solution obtained from this process cannot be directly utilized and thus requires purification.The effect of different conditions on the calcium and iron removal characteristics of modified steelmaking slag leaching solution was investigated.Additionally,the removal mechanism was analyzed by thermodynamic calculations.The results indicated that the addition of soybean straw ash in steelmaking slag modification enabled K_(2)O to enter the phosphorus-containing solid solution,promoting phosphorus enrichment.Valuable elements such as phosphorus and potassium were more easily dissolved in the mixed acid.The oxalic acid concentration had a significant effect on the calcium removal rate,whereas the effects of temperature,stirring rate,and time on the calcium removal rate were minor.The main component of the calcium removal precipitate was CaC_(2)O_(4)·H_(2)O,with a removal rate up to 94.48%.During the iron removal process,when the pH value of the solution was low,Fe^(3+)mainly reacted to form the iron hydroxide precipitate for removal.Increasing the pH value of the solution would cause Fe^(3+)to combine with H_(2)PO_(4)^(-),forming FePO_(4)·2H_(2)O precipitate,leading to a reduction in the phosphorus content of the leaching solution.
基金supported by the National Natural Science Foundation of China(Nos.52274304,52073199).
文摘The insufficient performance of Pt and Pd benchmark catalysts remains a significant obstacle to the practical application of direct liquid fuel cells.In this study,we report a synthesis of amorphous PdSe/crystalline Pt nanoparticles(AC-PdPtSe NPs)by chemical leaching of PdPtSe NPs.AC-PdPtSe NPs display significantly enhanced activity and stability for the electrooxidation of ethylene glycol and glycerol,far surpassing that of amorphous-dominant PdPtSe NPs,commercial Pd/C,and Pt/C catalysts.Notably,the integration of crystalline and amorphous domains leverages the advantages of high electrical conductivity and a wealth of active sites,which can substantially accelerate reaction kinetics.Furthermore,detailed investigations reveal that the boundary between the Pt crystalline and PdSe amorphous phases induces a 3%surface tensile strain.The formation of amorphous-crystalline heterointerfaces optimizes the d-band states,thereby strengthening the adsorption and activation of ethylene glycol and glycerol.This study highlights the advance in phase engineering toward the development of highly active noble-metal nanostructures.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.
基金supported by the National Natural Science Foundation of China(Nos.42077067,42277329)the Projects of Talents Recruitment of GDUPT(No.XJ2005000301)。
文摘Phosphorus(P)leaching in alkaline soils,exacerbated by excessive fertilizer application,represents a significant pathway for P loss.While soil pore structure and texture critically regulate P transport,mechanisms governing P loss in texturally diverse alkaline soils remain unclear.This study investigated P leaching dynamics and transport parameters across four alkaline soil textures(silty clay,clay loam,loam,sandy loam)using a one-dimensional convective-diffusion equation(CDE)based on column experiments.Results indicated that phosphorus leaching kinetics were predominantly governed by diffusion transport,evidenced by low Peclet numbers(P_(e))(ranged from 0.02 to 0.31)across varying textures and initial P concentrations(C_(0)).Comparative analysis of transport parameters revealed significant textural effects on dispersion coefficient(D),retardation factor(R),pore water velocity(V),P_(e),and diffusion coefficient(λ)(F>523.42,p<0.001).Among these,only D,P_(e) andλexhibited substantial differences in response to variations in C_(0)(F>89.47,p<0.001).Saturated hydraulic conductivity(K_(s))(R^(2)=62.9%,p<0.01)and total pore area(A)(R^(2)=12.4%,p<0.01)emerged as primary regulators of P leaching.Enhanced clay content increased total pore area while reducing average pore diameter,concurrently decreasing pore water velocity and saturated infiltration rates.These textural modifications amplified diffusive P transport within soil matrices.The findings provide mechanistic insights into texturedependent P mobility in alkaline environments,informing targeted strategies for agricultural phosphorus management.
基金supported by the National Natural Science Foundation of China(No.42077135).
文摘Heavy metal contamination of soil is one of the major challenges to sustainable agriculture.This contamination can be transmitted through the soil food chain and poses a serious threat to human health.In this study,we found that freeze-thaw leaching(FTL)effectively complements the low removal rate of chemical leaching,and investigated the effects of different numbers of FTL on Cd contamination,soil chemical properties and microbial communities.The results showed that repeated FTL significantly reduced(P<0.05)the total Cd content in the top soil(19.02%-49.35%)and subsoil(0.41%-21.13%)and promoted the transformation of Cd to a more stable form,mainly through various removal mechanisms such as complexation,ion-exchange,and chemical precipitation.This finding was supported by reductions in several soil properties,including pH,available potassium(AK),and available phosphorus(AP).FTL treatment initially increased the bioavailability of Cd compared to chemical leaching,but bioavailability of Cd progressively decreased as the number of freeze-thaw cycles increased.Additionally,FTL reduced the richness and diversity of bacteria communities,destabilized ecological symbiotic networks,while increasing the richness and diversity of fungi in the soil.Various model analyses indicated that FTL treatment,available Cd,soil pH,AP and AK were the key drivers influencing the changes in microbial community structure.This study provides new insights and scientific bases for the effective management of heavy metal pollution in agricultural soils,the restoration of ecosystem health,and the improvement of soil sustainability.
