The biosorption characteristics of Cs（I） ions from aqueous solution using exopolymers （PFC02） produced from Pseudomonas fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and in...The biosorption characteristics of Cs（I） ions from aqueous solution using exopolymers （PFC02） produced from Pseudomonas fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and initial concentration. pH played a major role in the adsorption process, and the optimum pH for the removal of Cs（I） was 8.0. Langmuir, Freundlich and Dubinin-Radushkevich （D-R） models were applied to describe the biosorption isotherm of the Cs（I） ions by PFC02. The Lagergren first-order, pseudo second-order kinetic and intraparticle diffusion models were used to test the kinetic data. Langmuir model and D-R model fitted the equilibrium data better than the Freundlich isotherm. The monolayer adsorption capacities of PFC02 as obtained from Langmuir isotherm at 25°C was found to be 32.63 mg/g. From the D-R isotherm model, the mean free energy was calculated as 26.73 kJ/mol, indicating that the biosorption of cesium was chemisorption. The biosorption process was rapid, and the kinetic rates were best fitted to the pseudo second-order model, which indicated the biosorption process operated through chemisorption mechanism. FT-IR analysis of PFC02 showed the possible functional groups responsible for cesium adsorption were hydroxyl, carboxyl, carbonyl and sulphonate groups. SEM analysis showed the porous structure of the material while EDX analysis confirmed the adsorption of Cs（I） on PFC02. Cesium adsorbed onto the PFC02 could be desorbed efficiently using 1 mol/L HNO 3 , and the enrichment factor was 50.0. Furthermore, PFC02 could be reused five times with only about 8.25% regeneration loss. The developed method was successfully utilized for the removal of Cs（I） ions from aqueous solution.展开更多
●Soil pH drives trace element mobility and bioavailability.●Bacterial β-diversity enhances trace element accumulation via functional diversity.●Uncultured bacterial ASVs are key in trace element cycling and plant ...●Soil pH drives trace element mobility and bioavailability.●Bacterial β-diversity enhances trace element accumulation via functional diversity.●Uncultured bacterial ASVs are key in trace element cycling and plant interactions.●Networks analysis showsPseudonocardia-Fe/As andBlastopirellula-Al regulatory nodes.Rice,feeding billions,accumulates both toxic trace elements(Cd,As,Al)and essential micronutrients(Se,Cu,Zn,Mn,Fe),posing food safety challenges.This study explores the interactions among soil properties,bacterial communities,and trace element dynamics across China's major paddy soil types.Our analysis showed that strongly acidic soils(pH≤5.5)had higher total As,Al,and Se,while neutral soils(6.5<pH≤7.5)exhibited greater Cd and Mn bioavailability.Bacterial diversity(alpha and beta)significantly influenced trace element accumulation in rice.Bacterial diversity,soil nutrients,and pH explained a large part of the variance in trace element content in soil(total:35.24%,21.69%,and 13.02%;bioavailable:23.68%,29.63%,and 11.81%)and rice grains(23.09%,10.25%,and 17.42%).Co-occurrence networks identified keystone bacterial ASVs,predominantly uncultured lineages(64%),strongly correlated with specific ASVs(R^(2)=0.53-0.80,P<0.001).Structural Equation Modeling revealed soil type,pH,and nutrients collectively explained 32%of bacterial alpha diversity and 75%of community composition variation,driving subsequent trace element distribution in soil and rice.Our findings underscore complex soil-microbe-element interactions,emphasizing managing soil pH and bacterial diversity to optimize rice nutrition of essential elements and mitigate risks from toxic elements.展开更多
Alum sludge is a typical by-product of drinking water treatment processes.Most sludge is disposed of at landfill sites,and such a disposal method may cause significant environmental concern due to its vast amount.This...Alum sludge is a typical by-product of drinking water treatment processes.Most sludge is disposed of at landfill sites,and such a disposal method may cause significant environmental concern due to its vast amount.This paper assessed the feasibility of reusing sludge as a supplementary cementitious material,which could efficiently exhaust stockpiled sludge.Specifically,the pozzolanic reactivity of sludge at different temperatures,the reaction mechanism of the sludge-cement binder,and the resistance of sludge-derived mortar to microbially induced corrosion were investigated.The obtained results indicated that 800℃ was the optimal calcination temperature for sludge.Mortar containing sludge up to 30%by weight showed comparable physical properties at a curing age of 90 days.Mortar with 10%cement replaced by sludge can significantly improve the resistance to biogenic corrosion due to the formation of Al-bearing phases with high resistance to acidic media,e.g.,Ca_(4)Al_(2)O_(7)·xH_(2)O and strätlingite.展开更多
基金supported by the National Nat- ural Science Foundation of China (No. 30970309)the Natural Science Foundation of He'nan Province (No. 082102220009)the Natural Science Foundation of He'nan Province Education Department (No. 2009A610001)
文摘The biosorption characteristics of Cs（I） ions from aqueous solution using exopolymers （PFC02） produced from Pseudomonas fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and initial concentration. pH played a major role in the adsorption process, and the optimum pH for the removal of Cs（I） was 8.0. Langmuir, Freundlich and Dubinin-Radushkevich （D-R） models were applied to describe the biosorption isotherm of the Cs（I） ions by PFC02. The Lagergren first-order, pseudo second-order kinetic and intraparticle diffusion models were used to test the kinetic data. Langmuir model and D-R model fitted the equilibrium data better than the Freundlich isotherm. The monolayer adsorption capacities of PFC02 as obtained from Langmuir isotherm at 25°C was found to be 32.63 mg/g. From the D-R isotherm model, the mean free energy was calculated as 26.73 kJ/mol, indicating that the biosorption of cesium was chemisorption. The biosorption process was rapid, and the kinetic rates were best fitted to the pseudo second-order model, which indicated the biosorption process operated through chemisorption mechanism. FT-IR analysis of PFC02 showed the possible functional groups responsible for cesium adsorption were hydroxyl, carboxyl, carbonyl and sulphonate groups. SEM analysis showed the porous structure of the material while EDX analysis confirmed the adsorption of Cs（I） on PFC02. Cesium adsorbed onto the PFC02 could be desorbed efficiently using 1 mol/L HNO 3 , and the enrichment factor was 50.0. Furthermore, PFC02 could be reused five times with only about 8.25% regeneration loss. The developed method was successfully utilized for the removal of Cs（I） ions from aqueous solution.
基金supported by the Major Program of the Natural Science Foundation of China(Grant Nos.22494680,22494682).
文摘●Soil pH drives trace element mobility and bioavailability.●Bacterial β-diversity enhances trace element accumulation via functional diversity.●Uncultured bacterial ASVs are key in trace element cycling and plant interactions.●Networks analysis showsPseudonocardia-Fe/As andBlastopirellula-Al regulatory nodes.Rice,feeding billions,accumulates both toxic trace elements(Cd,As,Al)and essential micronutrients(Se,Cu,Zn,Mn,Fe),posing food safety challenges.This study explores the interactions among soil properties,bacterial communities,and trace element dynamics across China's major paddy soil types.Our analysis showed that strongly acidic soils(pH≤5.5)had higher total As,Al,and Se,while neutral soils(6.5<pH≤7.5)exhibited greater Cd and Mn bioavailability.Bacterial diversity(alpha and beta)significantly influenced trace element accumulation in rice.Bacterial diversity,soil nutrients,and pH explained a large part of the variance in trace element content in soil(total:35.24%,21.69%,and 13.02%;bioavailable:23.68%,29.63%,and 11.81%)and rice grains(23.09%,10.25%,and 17.42%).Co-occurrence networks identified keystone bacterial ASVs,predominantly uncultured lineages(64%),strongly correlated with specific ASVs(R^(2)=0.53-0.80,P<0.001).Structural Equation Modeling revealed soil type,pH,and nutrients collectively explained 32%of bacterial alpha diversity and 75%of community composition variation,driving subsequent trace element distribution in soil and rice.Our findings underscore complex soil-microbe-element interactions,emphasizing managing soil pH and bacterial diversity to optimize rice nutrition of essential elements and mitigate risks from toxic elements.
基金funded by ARC Research Hub for Nanoscience-based Construction Material Manufacturing,Grant No.IH150100006General Project of National Natural Science Foundation of China (No.51778523)SA Water for the research scholarship and financial support for this project.
文摘Alum sludge is a typical by-product of drinking water treatment processes.Most sludge is disposed of at landfill sites,and such a disposal method may cause significant environmental concern due to its vast amount.This paper assessed the feasibility of reusing sludge as a supplementary cementitious material,which could efficiently exhaust stockpiled sludge.Specifically,the pozzolanic reactivity of sludge at different temperatures,the reaction mechanism of the sludge-cement binder,and the resistance of sludge-derived mortar to microbially induced corrosion were investigated.The obtained results indicated that 800℃ was the optimal calcination temperature for sludge.Mortar containing sludge up to 30%by weight showed comparable physical properties at a curing age of 90 days.Mortar with 10%cement replaced by sludge can significantly improve the resistance to biogenic corrosion due to the formation of Al-bearing phases with high resistance to acidic media,e.g.,Ca_(4)Al_(2)O_(7)·xH_(2)O and strätlingite.
