Microecological characteristics of water bodies/sediments and microbial remediation strategies after 50 years of pollution exposure in ammunition destruction sites in China.

The effects of long-term ammunition pollution on microecological characteristics were analyzed to formulate microbial remediation strategies. Specifically, the response of enzyme systems, N/O stable isotopes, ion networks, and microbial community structure/function levels were analyzed in long-term (50 years) ammunition-contaminated water/sediments from a contamination site, and a compound bacterial agent capable of efficiently degrading trinitrotoluene (TNT) while tolerating many heavy metals was selected to remediate the ammunition-contaminated soil. The basic physical and chemical properties of the water/sediment (pH (up: 0.57-0.64), nitrate (up: 1.31-4.28 times), nitrite (up: 1.51-5.03 times), and ammonium (up: 7.06-70.93 times)) were changed significantly, and the significant differences in stable isotope ratios of N and O (nitrate nitrogen) confirmed the degradability of TNT by indigenous microorganisms exposed to long-term pollution. Heavy metals, such as Pb, Zn, Cu, Cd, Cs, and Sb, have synergistic toxic effects in ammunition-contaminated sites, and significantly decreased the microbial diversity and richness in the core pollution area. However, long-term exposure in the edge pollution area induced microorganisms to use TNT as a carbon and nitrogen sources for life activities and growth and development. The Bacteroidales microbial group was significantly inhibited by ammunition contamination, whereas microorganisms such as Proteobacteria, Acidobacteriota, and Comamonadaceae gradually adapted to this environmental stress by regulating their development and stress responses. Ammunition pollution significantly affected DNA replication and gene regulation in the microecological genetic networks and increased the risk to human health. Mg and K were significantly involved in the internal mechanism of microbial transport, enrichment, and metabolism of TNT. Nine strains of TNT-utilizing microbes were screened for efficient TNT degradation and tolerance to typical heavy metals (copper, zinc and lead) found in contaminated sites, and a compound bacterial agent prepared for effective repair of ammunition-contaminated soil significantly improved the soil ecological environment.

Heuristics in vaccination Decision-Making for newly developed Vaccines: Understanding the public's imitative behavior.

This study aims to investigate the extent to which the public engages in imitative behavior in their vaccination decisions for newly developed vaccines in the Chinese context. Given the crucial role of newly developed vaccines in preventing and controlling the COVID-19 pandemic, a better understanding of how people make decisions about vaccination with new vaccines is important for overcoming vaccine hesitation and promoting widespread adoption of the vaccines. Our results indicate that the public's decision-making about the newly developed vaccine is influenced by a range of heuristics, including a privileged information heuristic, competence heuristic, and consensus heuristic. Specifically, individuals are more likely to imitate the vaccination behavior of those with privileged information, such as insiders, and those with perceived competence in the field, such as experts. Our findings also demonstrate the impact of majority influence, as the popularity of new vaccines leads to an increase in vaccination uptake through herd behavior. Our data highlights the importance of the first movers who are insiders with privileged information or experts with competence, as their behavior can significantly shape the vaccination decisions of others. Our study provides valuable insights into the complex interplay of heuristics and imitative behavior in vaccination decision-making for newly developed vaccines.

Rheological and radioactive decontamination properties of ethyl cellulose sols in green solvents at a temperature below 0 °C.

Strippable film decontamination has been considered one of the best prospects for radioactive surface decontamination due to its high decontamination effect and less secondary pollution. However, research into strippable films has until now focused on radioactive decontamination at room temperature. Therefore, it is vital to seek a suitable degradable material for preparing strippable films in removing contaminants in an extremely cold region, as it will face the problem of the freezing of the detergent. Ethyl cellulose (EC) is a kind of degradable biopolymer which is easily dissolved in volatile green organic solvents to form a sol below 0 °C which is advantageous for forming a film. Therefore, it would be the best choice for preparing a strippable film detergent. In this study, EC sols were obtained by placing EC powder into the green solvents anhydrous ethanol and ethyl acetate. The steady and dynamic rheological behavior of EC sols was investigated with a rotary rheometer with the temperature ranging from -10 °C to 0 °C to disclose their spraying performance. Moreover, the radioactive decontamination effect of EC sols and the mechanism were also investigated. The results showed that the EC sols were pseudoplastic fluids which obeyed the Ostwald-de Waele power law below 0 °C. Furthermore, the viscosity of EC sols could be reduced by stirring, which is convenient for large-area spraying during decontamination below 0 °C. At -10 °C, the comprehensive decontamination rates of all plates were over 85%. Therefore, EC sols could be used as a basic material for strippable film decontamination below 0 °C.

Analysis of environmental biological effects and OBT accumulation potential of microalgae in freshwater systems exposed to tritium pollution.

The ecological risk of tritiated wastewater into the environment has attracted much attention. Assessing the ecological risk of tritium-containing pollution is crucial by studying low-activity tritium exposure's environmental and biological effects on freshwater micro-environment and the enrichment potential of organically bound tritium (OBT) in microalgae and aquatic plants. The impact of tritium-contaminated wastewater on the microenvironment of freshwater systems was analyzed using microcosm experiments to simulate tritium pollution in freshwater systems. Low activity tritium pollution (105 Bq/L) induced differences in microbial abundance, with Proteobacteria, Bacteroidota, and Desulfobacterota occupying important ecological niches in the water system. Low activity tritium (105-107 Bq/L) did not affect the growth of microalgae and aquatic plants, but OBT was significantly enriched in microalgae and two aquatic plants (Pistia stratiotes, Spirodela polyrrhiza), with the enrichment coefficients of 2.08-3.39 and 1.71-2.13, respectively. At the transcriptional level, low-activity tritium (105 Bq/L) has the risk of interfering with gene expression in aquatic plants. Four dominant cyanobacterial strains (Leptolyngbya sp., Synechococcus elongatus, Nostoc sp., and Anabaena sp.) were isolated and demonstrated good environmental adaptability to tritium pollution. Environmental factors can modify the tritium accumulation potential in cyanobacteria and microalgae, theoretically enhancing food chain transfer.

First Display of Haloalkane Dehalogenase LinB on the Surface of Bacillus subtilis Spore.

BACKGROUND: LinB, as a Haloalkane dehalogenase, has good catalytic activity for many highly toxic and recalcitrant compounds, and can realize the elimination of chemical weapons HD in a green non-toxic mode. OBJECTIVES: In order to display Haloalkane dehalogenase LinB on the surface of Bacillus subtilis spore. METHODS: We have constituted the B. subtilis spore surface display system of halogenated alkanes dehalogenase LinB by gene recombination. RESULTS: Data revealed that LinB can display on spore surface successfully. The hydrolyzing HD analogue 2-chloroethyl ethylsulfide (2-CEES) activity of displayed LinB spores was 4.30±0.09 U/mL, and its specific activity was 0.78±0.03U/mg. Meanwhile, LinB spores showed a stronger stress resistance activity on 2-CEES than free LinB. This study obtained B. subtilis spores of LinB (phingobium japonicum UT26) with enzyme activity that was not reported before. CONCLUSION: Spore surface display technology uses resistance spore as the carrier to guarantee LinB activity, enhances its stability, and reduces the production cost, thus expanding the range of its application.

Effects of Different Types of Stabilizers on the Properties of Foam Detergent Used for Radioactive Surface Contamination.

Compared with high-pressure water and reagent washing decontamination, foam decontamination has a promising application due to its ability to significantly reduce the volume of radioactive waste liquids and effectively decontaminate the inner surface of the pipes, the interior of the large cavities, and the vertical walls. However, the foam is less stable, leading to a low decontamination rate. Currently, three main types of stabilizers with different stabilizing mechanisms, namely nanoparticles, polymers, and cosurfactants, are used to improve foam stability and thus increase the decontamination rate. Nanosilica (NS), xanthan gum (XG), and n-tetradecanol (TD) were used as typical representatives of nanoparticles, polymers, and cosurfactants, respectively, to improve the stability of the foam detergent with pH < 2 and chelating agents. The differences in the effects of these three types of stabilizers on foam properties were investigated. Although NS, XG, and TD all increase the half-life of the foam from 7.2 min to about 40 min, the concentration of TD is much lower than that of NS and XG in the foaming solution, and TD foaming solution has the highest foaming ratio. Moreover, TD can markedly lower the surface tension, resulting in a significant reduction of the wetting contact angle on the surfaces of glass, ceramic tile, stainless steel, and paint, while NS and XG cannot signally change the surface tension and have no obvious effect on the wetting contact angle. At low shear rates, TD can increase the apparent viscosity of foam by two orders of magnitude, and the wall-hanging time of the foam on the vertical wall is more than 30 min. In contrast, NS and XG cause a limited increase in the apparent viscosity of the foam, and the wall-hanging times are both less than 5 min. In addition, TD foaming solution has excellent storage stability, and the storage time has no obvious effect on the performance of the foam. And after only three days of storage, NS undergoes severe agglomeration and precipitation in the foaming solution, resulting in a complete loss of the stabilizing effect. After 90 days of storage, the half-life of XG foam decreases by 26%. For simulated radioactive uranium contamination on both horizontal and vertical surfaces, TD can significantly improve the decontamination rate, especially for vertical surfaces, where TD can increase the single decontamination rate by more than 50%.

Defense mechanisms of alfalfa against cyclic tetramethylene tetranitramine (HMX) stress.

Much attention has been paid to the environmental toxicity and ecological risk caused by cyclic tetramethylene tetranitramine (HMX) pollution in military activity sites. In this study, the response mechanism of alfalfa plants to HMX was analyzed from the aspects of the photosynthetic system, micromorphology, antioxidant enzyme system, mineral metabolism, and secondary metabolism, in order to improve the efficiency of plant restoration. Exposure to 5 mg·L-1 HMX resulted in a significant increase in leaf N content and a significant increase and drift of the Fourier transform infrared protein peak area. Transmission electron microscopy images revealed damage to the root system subcellular morphology, but the plant leaves effectively resisted HMX pressure, and the photosynthetic parameters essentially maintained steady-state levels. The root proline content decreased significantly by 23.1-47.2 %, and the root reactive oxygen species content increased significantly by 1.66-1.80 fold. The roots regulate the transport/absorption of many elements that impart stress resistance, and Cu, Mn, and Na uptake is significantly associated with secondary metabolism. The metabolism of roots was upregulated in general by HMX exposure, with the main differences appearing in the content of lipids and lipid-like molecules, further confirming damage to the root biofilm structure. HMX causes an imbalance in the energy supply from oxidative phosphorylation in roots and generates important biomarkers in the form of pyrophosphate and dihydrogen phosphate. Interestingly, HMX had no significant effect on basic metabolic networks (i.e., glycolysis/gluconeogenesis and the tricarboxylic acid cycle), confirming that alfalfa has good stress resistance. Alfalfa plants apparently regulate multiple network systems to resist/overcome HMX toxicity. These findings provide a scientific basis for improving plant stress tolerance and understanding the HMX toxicity mechanism.

Physiological response mechanism of alfalfa seedlings roots to typical explosive cyclotrimethylene trinitramine (RDX).

This study explored the physiological response mechanism of alfalfa seedlings roots to a typical explosive, cyclotrimethylenetrinitramine (RDX), so as to improve the efficiency of phytoremediation. The response of plants to different levels of RDX were analyzed from the perspectives of mineral nutrition and metabolic networks. Exposure to RDX at 10-40 mg L-1 had no significant effect on root morphology, but the plant roots significantly accumulated RDX in solution (17.6-40.9%). A 40 mg L-1 RDX exposure induced cell gap expansion and disrupted root mineral metabolism, The key response elements, P, Cu, and Mg, were significantly increased by 1.60-1.66, 1.74-1.90, and 1.85-2.50 times, respectively. The 40 mg L-1 RDX exposure also significantly disturbed root basal metabolism, resulting in a total of 197 differentially expressed metabolites (DEMs). The main response metabolites were lipids and lipid-like molecules, and the key physiological response pathways were arginine biosynthesis and aminoacyl-tRNA biosynthesis. A total of 19 DEMs in root metabolic pathways, including L-arginine, L-asparagine, and ornithine, were significantly responsive to RDX exposure. The physiological response mechanism of roots to RDX therefore involve mineral nutrition and metabolic networks and are of great significance for improving phytoremediation efficiency.

Generic detection of organophosphorus nerve agent adducts to butyrylcholinesterase in plasma using liquid chromatography-tandem mass spectrometry combined with an improved procainamide-gel separation and pepsin digestion method.

Organophosphorus nerve agent (OPNA) adducts to butyrylcholinesterase (BChE) can be applied to confirm exposure in humans. A sensitive method for generic detection of G- and V-series OPNA adducts to BChE in plasma was developed by combining an improved procainamide-gel separation (PGS) and pepsin digestion protocol with ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Residual matrix interferences from prior PGS purification of OPNA-BChE adducts from plasma were found to be a critical cause of significantly reduced UHPLC-MS/MS detection sensitivity. In our developed on-column PGS approach, the matrix interference was successfully removed by adding an appropriate concentration of NaCl to the washing buffer, and it could capture ≥92.5% of the BChE in plasma. The lower pH value and the longer digestion time in all previous pepsin digestion methods were found to be a key accelerated aging factor of several adducts such as tabun (GA)-, cyclohexylsarin (GF)-, and soman (GD)-BChE nonapeptide adducts, making them difficult to detect. The aging event of several OPNA-BChE nonapeptide adducts was so successfully addressed that the formic acid level in enzymatic buffer and digestion time were lowered to 0.05% (pH 2.67) and 0.5 h, respectively, and the post-digestion reaction was immediately terminated. The improved condition parameters were optimal for pepsin digestion of all types of OPNA-BChE adducts into their individual unaged nonapeptide adducts with the highest yields, expanding the applicability of the method. The method had a nearly one-fold decrease in sample preparation time through the reduction of digestion time and removal of ultrafiltration procedure after digestion. The limit of identification (LOI) were determined respectively as 0.13 ng mL-1, 0.28 ng mL-1, 0.50 ng mL-1, 0.41 ng mL-1 and 0.91 ng mL-1 for VX-, sarin (GB)-, GA-, GF-, and GD-exposed human plasma, being low exposure value compared to previously documented approaches. The approach was utilized to fully characterize the adducted (aged and unaged) BChE levels of five OPNAs in a series of their individual exposed concentration (1.00-400 nM) of plasma sample, and successfully detect OPNA exposure from all unknown plasma samples from OPCW's second and third biomedical proficiency tests. The OPNA-BChE adducts, their aged adducts, and unadducted BChE from OPNA-exposed plasma can simultaneously be measured using the method. The study provides a recommended diagnostic tool for generic verification of any OPNA exposure with high confidence by detecting its corresponding BChE adduct.

Tritium and Carbon-14 Contamination Reshaping the Microbial Community Structure, Metabolic Network, and Element Cycle in the Seawater Environment.

The potential ecological risks caused by entering radioactive wastewater containing tritium and carbon-14 into the sea require careful evaluation. This study simulated seawater's tritium and carbon-14 pollution and analyzed the effects on the seawater and sediment microenvironments. Tritium and carbon-14 pollution primarily altered nitrogen and phosphorus metabolism in the seawater environment. Analysis by 16S rRNA sequencing showed changes in the relative abundance of microorganisms involved in carbon, nitrogen, and phosphorus metabolism and organic matter degradation in response to tritium and carbon-14 exposure. Metabonomics and metagenomic analysis showed that tritium and carbon-14 exposure interfered with gene expression involving nucleotide and amino acid metabolites, in agreement with the results seen for microbial community structure. Tritium and carbon-14 exposure also modulated the abundance of functional genes involved in carbohydrate, phosphorus, sulfur, and nitrogen metabolic pathways in sediments. Tritium and carbon-14 pollution in seawater adversely affected microbial diversity, metabolic processes, and the abundance of nutrient-cycling genes. These results provide valuable information for further evaluating the risks of tritium and carbon-14 in marine environments.

Assessing the ecological risk of tritium and Carbon-14 discharge on cyanobacteria through metabolic profiling.

The ecological risk posed by tritium (T) and carbon-14 (C-14) discharge from nuclear accidents has gained attention. This study evaluated the toxic impact of T and C-14 (at a concentration of 37 kBq/L for 15 days) on the cyanobacteria (Synechococcus elongatus). The results showed that the assimilation efficiency of cyanobacteria was significantly higher for C-14 than T, and the intracellular C-14 activity reached 30.62-40.58 kBq/kg. T and C-14 exposure had no significant effect on cell proliferation but impacted photosynthesis and respiration. T exposure increased the content of Ca, Mg, Na, P, K, and Mn, while C-14 exposure primarily affected trace element absorption in cyanobacteria. 31, 27, and 58 different metabolites (DEMs) were identified under T, C-14, and combined exposure conditions. These DEMs were enriched in the amino acid biosynthesis pathway, and nitrogen assimilation was one of the crucial pathways affected by T and C-14 exposure. The absorption of mineral elements by cyanobacteria was influenced by the variation in metabolites in the ABC transporter pathway caused by T and C-14 exposure. Our findings provide insights into the metabolic response of cyanobacteria to T and C-14 exposure and will help to guide the ecological risk evaluation of nuclear accidents.

Effects of Fatty Alcohols with Different Chain Lengths on the Performance of Low pH Biomass-Based Foams for Radioactive Decontamination.

Compared with polymers and nanoparticles, fatty alcohols can not only increase the stability of foam, but also maintain better foamability at pH < 2, which is beneficial to reduce waste liquid and increase decontamination efficiency for radioactive surface pollution. However, different fatty alcohols have different hydrophobic chain lengths. The effects of fatty alcohols with different chain lengths on the performance of decontamination foam were studied at pH < 2, to assist in the selection of suitable fatty alcohols as foam stabilizers. Combined with betaine surfactant and phytic acid, biomass-based foams were synthesized using fatty alcohols with different chain lengths. When the hydrophobic tail groups of the fatty alcohol and the surfactant were the same, the foam showed the best performance, including the lowest surface tension, the highest liquid film strength, the greatest sag-resistance and the best stability. However, when the hydrophobic tail groups were different, the space between adjacent surface active molecules was increased by thermal motion of the excess terminal tail segments (a tail-wagging effect), and the adsorption density reduced on the gas-liquid interface, leading to increased surface tension and decreased liquid film strength, sag-resistance and stability. The use of decontamination foam stabilized by fatty alcohols with the same hydrophobic group as the surfactant was found to increase the decontamination rate of radioactive uranium pollution from 64 to over 90% on a vertical surface.

Fast and Selective Detection of Trace Chemical Warfare Agents Enabled by an ESIPT-Based Fluorescent Film Sensor.

Reliable detection of airborne chemical warfare agents (CWAs) at the site and in real-time remains a challenge due to the rarity of miniaturized analytical tools. Herein, an o-carborane-functionalized benzothiazole derivative (PCBO) with excited-state intramolecular proton transfer (ESIPT) and AIE characteristics was synthesized. The PCBO-based film sensor showed a highly sensitive response to representative simulants of CWAs, and detection limits were found to be 1.0 mg·m-3 for triphosgene, 6.0 mg·m-3 for chloroethyl ethyl sulfide, and 0.2 mg·m-3 for diethyl chlorophosphite. Moreover, the sensor showed great reusability (>100 cycles) and unprecedented response speed (<0.5 s). The excellent sensing performance was ascribed to the microenvironmental sensitivity of the sensing fluorophore, the porous adlayer structure of the film, and the specific binding of the fluorophore to the analytes. Furthermore, discrimination and identification of the examined CWA simulants were realized via the introduction of another fluorophore (HCBO)-based film. Importantly, a portable fluorescent CWA detector was built with the sensor as the key component, and its applicability was demonstrated by the successful detection of a typical CWA sample (Sarin). The present study indicates that fluorescent film sensors could satisfy reliable onsite and real-time detection of harmful chemicals.

Study on the composition and distribution characteristics of As in As-containing agent contaminated soil.

In recent years, China and Japan are cooperating in the destruction of the Japanese army abandoned chemical weapons in China (JACWs). During the long-term burial of JACWs, As-containing agents leaked into the environment due to the corrosion of the shell, resulting in soil As pollution. This paper studied the fraction, speciation, and composition of As in the soil polluted by the As-containing agent in Jilin, China. The results showed that As was mainly distributed in the forest soil in the study area, with the highest concentration of 110 mg/kg, and had the trend of migration to the downhill farmland soil. As mainly accumulated in the amorphous Fe/Al oxides bounded fraction and residual states, the proportion of potentially risky fractions in the soil of downhill farmland is higher than that of uphill farmland. The speciation of As in the soil is mainly As(V), with an average content of 25.02 mg/kg. The transformation behavior of As in the horizontal migration of topsoil is mainly the oxidation of As (III). The residual organic As in soil mainly includes 2-chlorovinylarsonic acid, triphenylarsine, phenylarsine oxide, and diphenylarsonic acid. Similar to the influence factors of As, both speciation and organic compounds of As are significantly affected by Fe/Al/Mn-oxides, and degradation and transformation reactions such as redox occur during migration.

A Sprayable and Visible Light Rapid-Cured Strippable Film for Surface Radioactive Decontamination.

Strippable film is effective for removing radioactive contamination. However, it still has some limitations, such as the long curing time (about 30 min~24 h) and the requirement of organic solvents. To address these issues, we report a simple protocol to prepare strippable decontamination films using liquid polybutadiene (LPB) and tert-butyl acrylate (TBA) as the raw materials without solvent and using camphorquinone/ethyl 4-dimethylaminobenzoate (CQ/EDB) as a photoinitiator, where the film was formed under household LED panel light or daylight irradiation for about 540 s. After a thorough study of viscosity, real-time Fourier transform infrared (RT-FTIR spectra), gel and volatile organic compound (VOC) contents, mechanical properties and decontamination efficiency, the optimum composition and curing conditions were determined for the decontamination strippable film. VOC content is as low as 12.7 ± 0.7% and the resultant strippable film exhibits good mechanical performances with a tensile strength of up to 5.4 ± 0.4 MPa and elongation of up to 66.6 ± 13%. Most important, the decontamination efficiencies of this strippable film for 133CsCl on glass, ceramic and metal surfaces reach up to 98.1%, 94.3% and 97.6%, respectively.

Arsenic in soils contaminated by arsenic-containing chemical weapons in a site of Jilin, China: fraction and bioaccessibility.

At the end of World War II, the Japanese abandoned arsenic (As)-containing chemical weapons (CWs) in China. During the long-term burial process, the As-containing agents leaked into the environment due to the corrosion of weapon shells. This study explored the surface distribution, fraction composition, and bioaccessibility of As in the soil contaminated by chemical weapons in a site of Jilin Province, China. Results showed that As was enriched in the soil of CWs buried and the maximum concentration of As in this area was 110 mg/kg (dry weight). In terms of fraction, As primarily accumulated in amorphous Fe/Al-oxides bound and residual fractions. Moreover, from the perspective of fractions with potential environmental risks, As accounted for 45.6-82.0% and 61.0-80.7% of the fractions extracted by Wenzel and Shiowatana sequential extraction procedure (SEP), respectively. Bioaccessibility can also be used to assess environmental risks. The mean values of As bioaccessibility were as follows: gastric phase (15.0%) > colon phase (14.8%) > small intestinal phase (13.3%), and the As bioaccessibility was closely related to the Fe/Al oxide bound fraction. Compared with the surrounding farmland, the potential environmental risk of soil pollution was more significant in the CW burial areas. This study provided support for remediation of As-containing agent-contaminated soil in China.

Plasma-assisted in-situ preparation of graphene-Ag nanofiltration membranes for efficient removal of heavy metal ions.

Graphene-based membranes have been considered as promising separation membranes for water treatments due to their unique two-dimensional confined channels. However, subject to the preparation technology, the effective construction of graphene-based filtration membranes with suitable separation ability on heavy metal ions still face considerable challenges. Herein, we have successfully constructed a kind of graphene-based (reduced graphene oxide, rGO) nanofiltration membranes by adopting a plasma-assisted in-situ photocatalytic reduction method. Graphene oxide-Ag (GO-Ag) composite sheets are prepared firstly and then assembled into membranes by vacuum filtration. With the use of Ag nanoparticles as plasmonic photocatalyst, GO-Ag films can be in-situ reduced, leading to the formation of rGO-based composite membranes. Thanks to the mild in-situ reduction process, the filtration ability on heavy metal ions (Cr(VI), Cr3+, Cu2+ and Pb2+) caused by lamellar structure is well retained in the as-formed rGO-Ag membranes. Especially, when treating the typical toxic Cr(VI) solution, the retention capacity, water flux and stability of rGO-Ag membranes are all improved compared with that of the original GO-Ag ones. In addition, the effectively rejection of Cr(VI) from mixed solutions containing both Cr(VI) and Cr(III) also suggests the good applicability of such rGO-Ag membranes in a complex wastewater system.

Hierarchically porous metal hydroxide/metal-organic framework composite nanoarchitectures as broad-spectrum adsorbents for toxic chemical filtration.

We demonstrate that the hierarchically porous metal hydroxide/metal-organic framework composite nanoarchitectures exhibit broad-spectrum removal activity for three chemically distinct toxic gases, viz. acid gases, base gases, and nitrogen oxides. A facile and general in-situ hydrolysis strategy combined with gentle ambient pressure drying (APD) was utilized to integrate both Zr(OH)4 and Ti(OH)4 with the amino-functionalized MOF-808 xerogel (G808-NH2). The M(OH)4/G808-NH2 xerogel composites manifested 3D crystalline porous networks and substantially hierarchical porosity, with controllable amounts of amorphous M(OH)4 nanoparticles residing at the edge of xerogel particles. Microbreakthrough tests were performed under both dry and moist conditions to evaluate the filtration capabilities of the composites against three representative compounds: SO2, NH3, and NO2. Compared with the pristine G808-NH2 xerogel, the incorporation of M(OH)4 effectively enhanced the broad-spectrum toxic chemical mitigation ability of the material, with the highest SO2, NH3, and NO2 breakthrough uptake reaching 74.5, 55.3, and 394.0 mg/g, respectively. Post-breakthrough characterization confirmed the abundant M-OH groups with diverse binding configurations, alongside the unsaturated M (IV) centers on the surface of M(OH)4 provided extra adsorption sites for irreversible toxic chemical capture besides Van der Waals driven physisorption. The ability to achieve high-capacity adsorption and strong retention for multiple contaminants is of great significance for real-world filtration applications.

Enhanced Adsorption and Mass Transfer of Hierarchically Porous Zr-MOF Nanoarchitectures toward Toxic Chemical Removal.

Zirconium-based metal-organic frameworks (Zr-MOFs) have shown tremendous prospects as highly efficient adsorbents against toxic chemicals under ambient conditions. Here, we report for the first time the enhanced toxic chemical adsorption and mass transfer properties of hierarchically porous Zr-MOF nanoarchitectures. A general and scalable sol-gel-based strategy combined with facile ambient pressure drying (APD) was utilized to construct MOF-808, MOF-808-NH2, and UiO-66-NH2 xerogel monoliths, denoted as G808, G808-NH2, and G66-NH2, respectively. The resulting Zr-MOF xerogels demonstrated 3D porous networks assembled by nanocrystal aggregates, with substantially higher mesoporosities than the precipitate analogues. Microbreakthrough tests on powders and tube breakthrough experiments on engineered granules were conducted at different relative humidities to comprehensively evaluate the NO2 adsorption capabilities. The Zr-MOF xerogels showed considerably better NO2 removal abilities than the precipitates, whether intrinsically or under simulated respirator canister/protection filter environment conditions. Multiple physicochemical characterizations were conducted to illuminate the NO2 filtration mechanisms. Analysis on adsorption kinetics and mass transfer patterns in Zr-MOF xerogels was further performed to visualize the underlying structure-activity relationship using the gravimetric uptake and zero length column methods with cyclohexane and acetaldehyde as probes. The results revealed that the synergy of hierarchical porosities and nanosized crystals could effectively expedite the intracrystalline diffusion for the G66-NH2 xerogel as well as alleviate the surface resistance for the G808-NH2 xerogel, which led to accelerated overall adsorption uptake and thus enhanced performance toward toxic chemical removal.

Co-remediation of PTEs contaminated soil in mining area by heat modified sawdust and herb.

Exploring efficient remediation technologies to remediate potentially toxic element (PTE) in soil around the mining area has become a trendy research topic. This study conducted material composed of sawdust ash (SA) and sawdust biochar (SB) with mass ratio of SA:SB = 1:2 in combination with Medicago sativa L. and Festuca arundinacea to remediate soil contaminated by zinc (Zn), cadmium (Cd), and arsenic (As) in a mining area. The result showed that the removal rates of Zn, Cd, and As were the highest under the treatment of Festuca arundinacea combined with 5% material with values of 22.15%, 22.05%, and 12.47%, respectively. Festuca arundinacea had the most potent ability to absorb and tolerate composite PTEs, and the co-remediation process could remarkably improve soil enzyme environment and microbial community diversity. The distribution of PTEs in plant subcellular showed that the accumulation of Zn, Cd, and As in the cell wall of Festuca arundinacea root was significantly increased by adding 2% materials. The concentrations of Zn, Cd, and As in the cell wall were 4486.25, 33.59, and 124.15 mg/kg, respectively. The combination of 2% material and Festuca arundinacea could effectively remove PTEs in soil and enhance the detoxification ability of the plant, thus effectively improving the soil environment and remediating PTEs pollution. This study provided insights into the remediation of PTE-contaminated soil in mining area by combining materials and plants.