The characteristics of fungal responses to uranium mining activities and analysis of their tolerance to uranium.

The influence of uranium (U) mining on the fungal diversity (FD) and communities (FC) structure was investigated in this work. Our results revealed that soil FC richness and FD indicators obviously decreased due to U, such as Chao1, observed OTUs and Shannon index (P<0.05). Moreover, the abundances of Mortierella, Gibberella, and Tetracladium were notably reduced in soil samples owing to U mining activities (P<0.05). In contrast, the abundances of Cadophora, Pseudogymnoascus, Mucor, and Sporormiella increased in all soil samples after U mining (P<0.05). Furthermore, U mining not only dramatically influenced the Plant_Pathogen guild and Saprotroph and Pathotroph modes (P<0.05), but also induced the differentiation of soil FC and the enrichment of the Animal_Pathogen-Soil_Saprotroph and Endophyte guilds and Symbiotroph and Pathotroph Saprotroph trophic modes. In addition, various fungal populations and guilds were enriched to deal with the external stresses caused by U mining in different U mining areas and soil depths (P<0.05). Finally, nine U-tolerant fungi were isolated and identified with a minimum inhibitory concentration range of 400-600 mg/L, and their adsorption efficiency for U ranged from 11.6% to 37.9%. This study provides insights into the impact of U mining on soil fungal stability and the response of fungi to U mining activities, as well as aids in the screening of fungal strains that can be used to promote remediation of U mining sites on plateaus.

Modeling competitive biosorption for methylene blue removal on rape straw powders using response surface methodology in a ternary dye aqueous solution.

The improvement of biosorption efficiency for selective dye removal in a multi-dye aqueous system has become an increasingly significant research topic. However, the competitive effects of coexisting dyes and the target dye in such systems remain uncertain due to complex interactions between adsorbent and coexisting dyes. Therefore, in this research, response surface methodology (RSM) model was effectively employed to investigate the competitive effects of allura red (AR) and malachite green (MG) on methylene blue (MB) removal in a ternary dye aqueous system using three different parts of rape straw powders. In the current design of RSM, the initial concentrations of AR and MG dyes ranging from 0 mg·L-1 to 500 mg·L-1 were considered as influencing factors, while the removal rates of MB on adsorbents at an initial concentration of 500 mg·L-1 were established as response values. The RSM models exhibited high correlation coefficients with adjusted R2 values of 0.9908 (pith core), 0.9870 (seedpods), and 0.9902 (shells), respectively, indicating a close fitted between predicted and actual values. The proposed models indicated that the perturbation effects of initial AR and MG concentrations were observed on the removal rates of MB by three types of rape straw powders in a ternary dye aqueous system, resulting in a decrease in MB removal rates, particularly at higher initial AR concentration due to stronger competitive effects compared to initial MG concentration. The structures of rape straw powders, including pith core, seedpods and shell, were analyzed using scanning eletron microscoe (SEM), energy dispersive spectroscopy (EDS), N2 physisorption isotherm, frourier transform infared spectroscopy (FTIR), Zeta potential classes and fluorescence spectrum before and after adsorption of MB in various dye aqueous systems. The characteristics of rape straw powders suggested that similar adsorption mechanisms, such as electrostatic attraction, pore diffusion, and group complex formation for MB, AR, and MG, respectively, occurred on the surfaces of adsorbents during their respective adsorption processes. This leads to significant competitive effects on the removal rates of MB in a ternary dye aqueous system, which are particularly influenced by initial AR concentrations as confirmed through fluorescence spectrum analysis.

Impact of AR and MG on MB removal was analyzed using simple methodologies.Competitive behaviors between AR, MG and MB were understood through RSM.Intense restrain effects on MB removal were revealed by AR concentration.

Hydrogel immobilized bacteria@MOFs composite towards Bisphenol A degradation and the interconnection mechanism elucidation.

Bisphenol A (BPA) degradation efficiency by bacteria or by metal-organic-frameworks (MOFs) catalyzed persulfate (PMS) oxidation have been studied intensively. However, their synergistic effect on BPA degradation was less reported. In this study, we combined previously synthesized CNT-hemin/Mn-MOF with an BPA degrading bacteria SQ-2 to form a composite (SQ-2@MOFs). CNT-hemin/Mn-MOF in the composite catalyzed little PMS to promote the degradation efficiency of SQ-2 on BPA. Results indicated SQ-2@MOFs significantly accelerated BPA degradation rate than SQ-2 alone. Furthermore, SQ-2@MOFs composite was successfully immobilized in hydrogel to achieve better degradation performance. Immobilized SQ-2@MOFs could almost completely degrade 1-20 mg/L BPA within 24 h and completely degrade 5 mg/L BPA at pH 4-8. Besides, degradation byproducts also reduced by immobilized SQ-2@MOFs, which promoted the cleaner biodegradation of BPA. Metabolomics and multiple chemical characterization results revealed the interconnection mechanism between CNT-hemin/Mn-MOFs, SQ-2 and hydrogel. CNT-hemin/Mn-MOF helped SQ-2 degrade BPA into more biodegradable products, promoted electron transfer, and augmented BPA degradation ability of SQ-2 itself. SQ-2 enabled the surface electronegativity of SQ-2@MOFs more suitable for BPA contact. Meanwhile, SQ-2 avoided the loss of Fe and Mn of CNT-hemin/Mn-MOF. Hydrogel augmented the above synergistic effect. This study provided new perspective for the development of biodegradation materials through interdisciplinary integration.

Tunable dual-emission of Sb3+, Ho3+Co-doped Cs2NaScCl6single crystals for light-emitting diodes.

Lead-free halide double perovskites are considered as one of the most promising materials in optoelectronic devices, such as solar cells, photodetectors, and light-emitting diodes (LEDs), due to their environmental friendliness and chemical stability. However, the extremely low photoluminescence quantum yield (PLQY) of self-trapped excitons (STEs) emission from lead-free halide double perovskites impedes their applications. Herein, Sb3+ions were doped into rare-earth-based double perovskite Cs2NaScCl6single crystals (SCs), resulting in a large enhancement of PLQY from 12.57% to 87.37%. Moreover, by co-doping Sb3+and Ho3+into Cs2NaScCl6SCs, the emission color can be tuned from blue to red, due to an efficient energy transfer from STEs to Ho3+ions. Finally, the synthesized sample was used in multicolor LED, which exhibited excellent stability and optical properties. This work not only provides a new strategy for improving the optical properties of Cs2NaScCl6SCs, but also suggests its potential application in multicolor LEDs.

Optimization and mechanisms of methylene blue removal by foxtail millet shell from aqueous water and reuse in biosorption of Pb(II), Cd(II), Cu(II), and Zn(II) for secondary times.

Foxtail millet shell as a raw efficient adsorbent was chosen first to eliminate methylene blue (MB) based on the uneven surface with many micropores, lots of negative charges, various functional groups, and some primary elements. And then the adsorbent-loaded MB was used to remove Pb(II), Cd(II), Cu(II), and Zn(II) from aqueous water for secondary adsorption. The effects of various factors were explored and optimized for removal rates of MB on the surface of the adsorbent using response surface methodology (RSM). After these factors were optimized, the confirmed removal rates of MB by the adsorbents were reached at 92.04, 93.05, and 93.36%, respectively from aqueous water while the solution pH was at 3, 7, and 11, respectively. The behavior of adsorption for MB dye was well-described by Langmuir isotherm (R2 = 0.9951), demonstrating favorable monolayer adsorption of MB on the adsorbent with the maximum capacity of 165.07 mg·L-1 in aqueous water. The data of MB dye removal was better assessed by pseudo-second-order model (R2 ≥ 0.9033), indicating an exchange of electrons has occurred between the adsorbent and MB particles, especially K and Ca ions of the adsorbent. In addition, the adsorbent-loaded MB has still presented better adsorption abilities for Pb(II), Cd(II), Cu(II), and Zn(II), respectively after MB removal in aqueous water. The adsorption mechanisms of adsorption were explored with the characterizations of the adsorbent before and after adsorption for the target pollutants by the methods of TEM, SEM, nitrogen physisorption isotherms, XPS, EDS, IR, and zeta potential classes. In summary, the results presented that the foxtail millet shell could be applied to remove MB dye effectively from aqueous water with the combined effects of electrostatic attraction, ion exchange, functional groups binding, and pore diffusion, but also, the adsorbent loaded with MB can be still applied to eliminate Pb(II), Cd(II), Cu(II), and Zn(II) by effects of electrostatic attraction and functional groups complexation in aqueous water.Novelty Statement In the present work, (a) the raw foxtail millet shell as a new potential adsorbent was used to remove MB dye from aqueous water for the first times, and operational variables of adsorption MB were investigated and optimized using response surface methodology, (b) the foxtail millet shell loaded MB as a disused adsorbent without any chemical reagent added was carried out to remove Pb(II), Cd(II), Cu(II), and Zn(II) ions, respectively in aqueous water for a secondary cycle, (c) adsorption mechanisms of MB removal on the adsorbent and the target heavy metals on the disused adsorbent were explored by the various analytical methods. This work provides evidence for the adsorption of MB on the natural adsorbent and improves the utilization efficiency of the used adsorbent on Pb(II), Cd(II), Cu(II), and Zn(II) removal in aqueous water.

A field study on the effects of combined biomanipulation on the water quality of a eutrophic lake.

Lake eutrophication has become a serious environmental problem in China. Manipulations covering more elements of trophic pyramid are methods for lakes to obtain clear water state and should be studied in detail. In the present study, Meishan Dongpo Lake was divided into two parts, and a combined biomanipulation project was conducted in one part (RLake), and the other part was used as a control (CLake). Species of submerged-plant, fish, macrobenthos, and zooplankton were screened and a certain number of them were added to adjust the eco-chain in RLake. After restoration, the coverage of submerged macrophytes reached >85%; zooplankton greater than 0.6 mm in size increased in number, and the ratio of zooplankton biomass to chlorophyll-a (Chl-a) concentration increased. The dominant fish species changed, and disturbance of the sediment was reduced. The average density of mollusks in RLake was 111.5 ± 19.8 ind m-2, which was much higher than that in CLake (36.7 ± 2.1 ind m-2). Water quality and clarity were substantially improved, and nutrient concentrations, particularly total phosphorus, total nitrogen, and Chl-a were significantly reduced. The aquatic community parameters were negatively correlated with the nutrient parameters and Chl-a. The ecological restoration have adjusted the aquatic ecosystem in RLake, and many positive feedback effects among the aquatic communities made them remove internal nutrients and Chl-a more efficiently.

Encapsulation of Escherichia coli strain Nissle 1917 in a chitosan-alginate matrix by combining layer-by-layer assembly with CaCl2 cross-linking for an effective treatment of inflammatory bowel diseases.

Escherichia coli strain Nissle 1917 (EcN) has been widely shown to effectively treat inflammatory bowel diseases (IBDs). Unfortunately, after oral administration, EcN viability dramatically decreases due to severe environmental factors, including low gastric pH, temperature and osmotic pressure. To address these challenges and improve oral bio-availability, this study utilized layer-by-layer assembly (LbL) and ionic cross-linking with CaCl2 as a method of EcN encapsulation (GEcN). Upon examination, GEcN cells were shown to maintain their ability to grow and proliferate, but had a slightly longer stationary phase (10 h) relative to free EcN (4 h). When exposed to simulated gastric fluid (SGF), a higher number of GEcN cells survived up to 12 h when compared to the other groups. To assess the therapeutic effect of EcN encapsulation in vivo, a TNBS-induced colitis rat model was established. When compared with the oral administration of free EcN, GEcN exhibited a significantly enhanced anti-inflammatory effect. Furthermore, GEcN treatment showed a lower disease activity index (DAI), decreased pro-inflammatory cytokine expression (MPO, TNF-α, IL-6) and increased anti-inflammatory cytokine expression (IL-10). Additionally, rats that received GEcN had much higher ZO-1 expression levels. These results suggest that EcN encapsulation in a chitosan-alginate matrix when utilizing the LbL assembly with CaCl2 cross-linking can improve probiotic viability in a gastric environmental and thereby offer a more effective treatment for IBDs.

Optimization and mechanisms of biosorption process of Zn(II) on rape straw powders in aqueous solution.

The different part powders of rape straw as adsorbents were performed to remove zinc ions from aqueous solution in this work. The various factors on influencing removal efficiency of Zn(II) were investigated, and the operational conditions were optimized using the Box-Behnken design of response surface methodology (RSM). Under the optimum conditions obtained, the removal rates of Zn(II) were attained to 100.00%, 78.02%, and 17.00% by straw pith core, seedpods, and shell of rape straw, respectively. Equilibrium and kinetic models were applied to evaluate the adsorption behaviors of Zn(II) on the adsorbents. The equilibrium data were best described by the Langmuir isotherm model, which indicated that the adsorption behaviors were favorably monolayer adsorption processes. The biosorption capacities of Zn(II) were 34.66 mg g-1, 36.41 mg g-1, and 36.74 mg g-1 of rape straw pith core; 23.33 mg g-1, 23.85 mg g-1, and 24.30 mg g-1 of seedpods; and 11.19 mg g-1, 11.23 mg g-1, and 11.27 mg g-1 of shell, respectively, at the various temperatures of 20 °C, 30 °C, and 40 °C based on Langmuir isotherm equation. The pseudo-second-order kinetic model was well to determine the adsorption kinetics, which suggested that ion exchange were occurred during adsorption processes of Zn(II). The characteristics of adsorbents before and after adsorption of Zn(II) were measured using the methods of scanning electron microscope (SEM), zeta potential classes, energy dispersive spectrometer (EDS), and Fourier transform infrared spectroscopy (FT-IR), respectively. The results provided evidences for the adsorption mechanisms of Zn(II) including electrostatic attraction, ion exchange, and functional group involvement on the three part powders of rape straw in aqueous water.

How backfill soil type influencing on Cd and Pb migration in artificial soil on railway rock-cut slopes.

Cadmium (Cd) and lead (Pb) that accumulates in the surface soil of railway rock-cut slopes may migrate to nearby croplands. It is important to determine whether backfill soil type influences the transportation of Cd and Pb in the surface soil. Representative rock-cut slopes, backfill soil of 100% rock fragments, 100% agricultural soil, and 50% agricultural soil and 50% rock fragments (n = 2 for each type) were selected. The pollution and migration levels of Cd and Pb and the soil quality and erodibility were investigated. The soil concentrations of Cd and Pb on the rock-cut slopes were much higher than those of China soil quality standard. Soil erosion was the most important factor that influences the migration of Cd and Pb in the slopes. Increasing the percentage of agricultural soil in the backfill soil resulted in decreasing the diffusion of Cd and Pb by reducing soil erosion. The backfill soil affected the soil quality and erosion durability, which, in turn, affected the transportation of Cd and Pb in the runoff. The soil quality index (SQI) accurately reflects the soil quality and can serve as an indicator of the migration of Cd and Pb on the surface soil of the slopes. Therefore, agricultural soil was more appropriate to use as a backfill soil in slope revegetation practice than was the rock fragment, which was helpful for decreasing the environmental risk of Cd and Pb on the slopes.

Biosorption of copper ions from aqueous solution using rape straw powders: Optimization, equilibrium and kinetic studies.

In this paper, the adsorption behaviors of Cu(II) from the aqueous solution using rape straw powders were studied. The effects of initial Cu(II) concentration, pH range and absorbent dosage on the adsorption efficiency of Cu(II) by rape straw powder were investigated by Box-Behnken Design based on response surface methodology. The values of coefficient constant of the nonlinear models were 0.9997, 0.9984 and 0.9944 for removal Cu(II) from aqueous solution using rape straw shell, seed pods and straw pith core, respectively, which could navigate the design space for various factors on effects of biosorption Cu(II) from aqueous solution. The various factors of pH and biosorbents dosage were the key factors that affecting the removal efficiency of Cu(II) from aqueous solution. The biosorption equilibrium data presented its favorable monolayer adsorption Cu(II) onto shell, seed pods and straw pith core, respectively. The pseudo-second order kinetic model was the proper approach to determine the adsorption kinetics. The biosorption of Cu(II) onto surfaces of rape straw powders were confirmed and ion-exchanged in the adsorption process by energy dispersive spectrometer. The critical groups, -OH, -CH, -NH3+, -CH3, -NH and -C-O, exhibited by the infrared spectra results, changed to suggest that these groups played critical roles, especially -CH3 in the adsorption of copper ions onto rape straw powders. The study provided evidences that rape straw powders can be used for removing Cu(II) from aqueous water.

Effects and mechanisms of revegetation modes on cadmium and lead pollution in artificial soil on railway rock-cut slopes.

Artificial soil on railway rock-cut slopes may be considerably contaminated with cadmium (Cd) and lead (Pb), which may migrate to nearby croplands and pose substantial risks to human and animal health. We investigate the influence of three types of revegetation modes - herbs (HS); herbs and shrubs (HSS); and herbs, shrubs, and trees (HSTS) - on the transportation of these heavy metals in soils. Six representative rock-cut slopes were chosen, and the vegetation, pollutant concentration, phytostabilization, and simulated rainfall were investigated. The results indicated that Cd posed a considerable ecological risk, while Pb posed a low ecological risk in the artificial soil. The erosion of artificial soil on the slopes played a primary role in the migration of Cd and Pb, because 87-91% of Cd and 85-89% of Pb was lost in sediments. Revegetation modes significantly affected the transportation of Cd and Pb. HSTS controlled a lot of Cd in their dominant plants among the three revegetation modes. HSTS not only decreased enrichment factor (EF) and ecological risk (Er) values of Cd in the soils, but also decreased runoff, sediment and cumulative migrated Cd and Pb. The relationships among multi-factors were analyzed by stepwise mediation effect test and the results indicated that root weight density, aboveground biomass and immobilization of dominant plants for Cd and Pb were important direct factors which influenced the transportation of Cd and Pb. Overall, HSTS has proven to be beneficial in controlling the migration of Cd and Pb to croplands near the slopes and reducing their environmental risk. These results can offer a tested and implementable solution for mitigating the risks posed by these pollutants around the quickly expanding railways in the study region.

The physico-chemical properties and structural characteristics of artificial soil for cut slope restoration in Southwestern China.

Cut slopes are frequently generated by construction work in hilly areas, and artificial soil is often sprayed onto them to promote ecological rehabilitation. The artificial soil properties are very important for effective management of the slopes. This paper uses fractal and moment methods to characterize soil particle size distribution (PSD) and aggregates composition. The fractal dimension (D) showed linear relationships between clay, silt, and sand contents, with coefficients of determination from 0.843 to 0.875, suggesting that using of D to evaluate the PSD of artificial soils is reasonable. The bias (CS) and peak convex (CE) coefficients showed significant correlations with structure failure rate, moisture content, and total porosity, which validated the moment method to quantitatively describe soil structure. Railway slope (RS) soil has lower organic carbon and soil moisture, and higher pH than natural slope soil. Overall, RS exhibited poor soil structure and physicochemical properties, increasing the risk of soil erosion. Hence, more effective management measures should be adopted to promote the restoration of cut slopes.

Impact of Soil Composition and Electrochemistry on Corrosion of Rock-cut Slope Nets along Railway Lines in China.

Taking the slope of Suiyu Railway to study, the research separately studied soil resistivity, soil electrochemistry (corrosion potential, oxidization reduction potential, electric potential gradient and pH), soil anions (total soluble salt, Cl(-), SO4(2-) and ), and soil nutrition (moisture content, organic matter, total nitrogen, alkali-hydrolysable nitrogen, available phosphorus, and available potassium) at different slope levels, and conducted corrosion grade evaluation on artificial soil according to its single index and comprehensive indexes. Compared with other factors, water has the biggest impact on the corrosion of slope protection net, followed by anion content. Total soluble salt has the moderate impact on the corrosion of slope protection net, and stray current has the moderate impact on the corrosion of mid-slope protection net. Comprehensive evaluation on the corrosive degree of soil samples indicates that the corrosion of upper slope is moderate, and the corrosion of mid-slope and lower slope is strong. Organic matter in soil is remarkably relevant to electric potential gradient. Available nitrogen, available potassium and available phosphorus are remarkably relevant to anions. The distribution of soil nutrient is indirectly relevant to slope type.

Distribution and phytoavailability of heavy metal chemical fractions in artificial soil on rock cut slopes alongside railways.

Artificial soil is often sprayed onto cut slopes alongside railroad tracks to promote revegetation. This study evaluated the heavy metal content and the distribution of heavy metal chemical fractions in the soil, as well as the uptake of heavy metals by plants. The soil at four sites was determined to be considerably contaminated with Cd and Pb. The concentrations of Cd and Pb increased with the length of time the railway had been in use and decreased further away from the railway tracks. Pb primarily existed in reducible form but as residual fractions, whereas Cd was predominantly in exchangeable form. A correlation analysis indicated that pH, organic matter, and total phosphorus levels were important factors affecting the distribution of the heavy metal chemical fractions. The amounts of exchangeable Pb and Cd in the soil were highly correlated with their amounts in the plants sampled, indicating that the exchangeable fraction is a better indication of heavy metal phytoavailability than the total amount of heavy metals in the soil. Bioaccumulation and translocation factors indicated that Indigofera amblyantha had moderate tolerance and bioaccumulation capability for Pb, as did Leucaena leucocephala for Cd. These two plant species can serve as ideal slope remediation plants.

The effects of railway transportation on the enrichment of heavy metals in the artificial soil on railway cut slopes.

Heavy metal contamination in the artificial soils on the railway cut slopes may have great influence on the revegetation of the cut slopes. The purpose of this study was to assess the variation of heavy metal contamination levels with railway operation time and analyze their possible resources. A total of 100 soil samples from four cut slopes, which were affected by railway transportation for different years, were analyzed for metal pollution (Cd, Pb, Cr, Cu, Zn, Fe). The concentrations of Cd, Pb showed increasing trend with increasing operation time of railways, while such trend was not found in Cr, Cu, Zn, Fe. According to the soil quality standard of China, Cd was considered to have considerable contamination, while Pb has less, but Cr, Cu, Zn, Fe have none. Moreover, cadmium exhibited remarkably higher levels rather than those reported in other studies. Enrichment factors and ecological index showed that Cd and Pb showed a moderate enrichment and a considerable ecological risk in most of the soil samples. The results of descriptive statistic, principal component analysis, cluster analysis and correlation analysis were totally consistent with each other. Their results revealed that Cr, Cu, Zn and Fe had common origins, and they may come from natural resources. While Cd and Pb were significantly influenced by railway transportation, leaked cargos, fuel combustion, the use of lubricate oils and sleeper impregnation oils during railway transportation may be their main resources.

[Determination of heavy metals in artificial soil on railway rock-cut slopes by microwave digestion-AAS].

The purpose of this paper is as follows: (1) Optimizing the parameters of microwave digestion-atomic absorption spectroscopy (AAS) and establishing method for the determination of heavy metals in artificial soils. (2) Evaluating heavy metal pollution conditions in artificial soil samples from railway rock-cut slopes. The results showed that the mixture of HNO3-H2O2-HF was found to have the best digestion efficiency; under the optimized conditions, the recoveries of the method ranged from 95% to 105%; the measurement precision and the relative deviation were less than 4% and 5%, respectively; the concentrations of Cd, Pb and Zn were significantly higher in the artificial soil on railway rock-cut slope than in the control soil, and they were 4.7, 1.3 and 1.2 times as much as the control soil, respectively; compared to the contents of Cr, Cu and Fe in control soils, there was no significant difference. This research will provide a reliable method for determining metal elements in artificial soils on rock-cut slopes and a theoretical basis for the management of the railway rock-cut slopes.

[Determination of heavy metal by AAS in railway rock-cut slope soil].

Heavy metal contents in railway rock-cut slope soil have directly influenced ecosystem on rock-cut slope and eco-envi- ronment safety of farmland nearby. In the study heavy metal Pb, Cd, Zn, Cu and Mn was determined by AAS in railway rock-cut slope and control soil samples on Cheng-Da Railway crossing purple soil in Sichuan province. The results showed that Pb and Mn were significantly higher in rock-cut soil than in control soil, that is 29.7%-35.4%, while Cd, Zn and Cu were similar in both soils.

[Isolation of PVA-degrading symbiotic bacteria and examination of degradation characters].

From printing and dyeing actived sludge, PVA- degrading symbiotic bacteria was isolated. The symbiotic bacteria is composed of B1 and B2. During PVA biodegradation, B1 produces a certain growth factor for B2, B2 produces PVA-degrading enzyme. The PVA-degrading characters of the symbiotic bacteria are examined. When the concentration of PVA was 0.1, 0.5, 1g/L respectively,more than 80% of PVA was degradated after 7days. During the treatment of the dyeing and printing wastewater, when the temperature was 30 degree C ,the removal of COD(Cr) was 69.75%, the proper treating time was 12h.