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Efficient adsorption of radioactive 137Cs+ and 60Co2+ and their decay products 137Ba2+ and 60Ni2+ bears significance for hazard elimination in case of nuclear emergency, which relies on the adsorption rate enhancement that takes advantages of compositional and structural optimization. Herein, we report a zinc-doped selenidostannate constructed from T2-supertetrahedral clusters, namely K 3.4 (CH 3 NH 3) 0.45 (NH 4) 0.15 Zn 2 Sn 3 Se 10 ·3.4 H 2 O (ZnSnSe‐1K). The soft Se and micro-porosity synergistically endow this material with a binding affinity to Cs+, Ba2+, Co2+, and Ni2+ ions and ultrafast kinetics with R > 97.6% in 2–60 min. In particular, ZnSnSe‐1K can remove 99.34% of Cs+ in 2 min ( K d Cs > 1.5 × 105 mL g−1), contributing to a record rate constant k 2 of 9.240 g mg−1 min−1 that surpasses all metal chalcogenide adsorbents. ZnSnSe‐1K exhibits good acid/base tolerance (pH = 0–12), and the adsorption capacities at neutral are 253.61 ± 9.15, 108.94 ± 25.32, 45.76 ± 14.19 and 38.49 ± 2.99 mg g−1 for Cs+, Ba2+, Co2+, and Ni2+, respectively. The adsorption performances resist well co-existing cations and anions, and the removal rates can keep above or close to 90% even in sea water. ZnSnSe‐1K is employed in continuous column and membrane filtration, both of which shows excellent elimination efficiency (R > 99%) for mixed Cs+, Ba2+, Co2+, and Ni2+. Especially, the membrane with an ultrathin (70 µm) ZnSnSe‐1K layer can remove 97–100% Cs+ in suction filtration with a short contact time of 0.33 s. Combined with the simple synthesis, facile elution and great irradiation resistance, ZnSnSe‐1K emerges as a selenide adsorbent candidate for use in environmental remediation especially that involving nuclear waste disposal. [Display omitted] • Adsorption rate enhancement through construction of microporous selenide ZnSnSe-1K. • Record rate constant k 2 of 9.240 g mg−1 min−1 that surpasses all metal chalcogenides. • Removal of 97–100% Cs+ through an ultrathin (70 µm) membrane of ZnSnSe‐1K under suction filtration. • Good adsorption selectivity in presence of co-existing ions, even in actual sea water. • Great pH (0−12)/irradiation resistance, outstanding column/membrane performances, and facile elution. [ABSTRACT FROM AUTHOR]

Mineral fines act a pivotal part in determining the fate and behavior of oil. In this study, the infiltrations of oil emulsion in simulated sediments and natural shoreline sediments were investigated using a fixed bed experiment. Oil infiltration process was simulated based on fixed-bed dispersion model. The role of mineral fines in oil release was explored using simulated and natural sediments. Although mineral fines exhibited a higher affinity for oil, it was found that increasing fines fractions decreased the flow rate of oil emulsion, thereby decreasing the oil retention in the sediment column. In terms of oil release from the sediment, the highest level of oil mass was observed in the oil-mineral flocculation phase compared to the water column and the water surface compartments. Compared to light crude oil, the release of engine oil from sediment was less. The effects of mineral fines on oil infiltration and release were also confirmed by using natural shoreline sediments. Results of our detailed field studies also showed that current shoreline classification datasets do not characterize the presence and fraction of mineral fines at a level of detail required to accurately predict the significance of oil translocation following spill incidents. [Display omitted] • Shoreline mineral fines act a pivotal part in determining the oil translocation. • Effects of mineral fines in oil infiltration were simulated using fixed-bed model. • Increasing fines fraction decreased the flow velocity and oil retention. • Highest oil mass was observed in the fines-oil flocculation phase. • Shoreline sample analysis underlined the need to explore fine segments for cleanup. [ABSTRACT FROM AUTHOR]

Understanding the interactions between oil and other particles in shoreline can help determine the environmental risk and cleanup strategy after oil spill. Nevertheless, far less has been known regarding the impact of aged MPs on oil behavior in the shoreline environment. In this study, the aging course of polyethylene (PE) in shaking seawater and ultraviolet (UV) radiation conditions was investigated. The seawater aging mainly affected the physical properties of MPs, increasing its surface pores and hydrophilicity. UV aging significantly affected both the physical and chemical properties of MPs, which increased its hydrophilicity and crystallinity, decreased its mean particle size and introduced oxygen-containing functional groups onto MPs. The two-dimensional correlation spectroscopy (2D COS) analysis confirmed the evolution of oxygen-containing functional groups from C–O to C O. The effects of aged MPs on oil behavior in water-sand system were further explored. The oil remaining percentages were non-linearly changed with the increasing aging degree of MPs. The particle size of the aqueous phase after washing was inversely related to the oil remaining percentage. Further FTIR analysis revealed that C–O and C–H functional groups played an important role in the process of oil adsorbed on MPs. [Display omitted] • The changes of microplastics under seawater-aging and UV-aging are distinctive. • Aged microplastics can impact the transport of oil in shoreline environments. • A higher amount of oil droplet contributes to the aggregation with microplastics. • C–O and C–H functional groups play an important role in the binding process. • Effects are determined by the trade-offs between oil-microplastic interactions. [ABSTRACT FROM AUTHOR]

Abstract: The composite modified double base (CMDB) propellants (nos. RB0601 and RB0602) containing 3,6-bis (1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz) without and with the ballistic modifier were prepared and their thermal behaviors, nonisothermal decomposition reaction kinetics, thermal safety and burning rates were investigated. The results show that there are three mass-loss stages in TG curve and two exothermic peaks in DSC curve for the BTATz-CMDB propellant. The first two mass-loss stages occur in succession and the temperature ranges are near apart, and the decomposition peaks of the two stages overlap each other, inducing only one visible exothermic peak appear in DSC curve during 350–550K. The reaction mechanisms of the main exothermal decomposition processes of RB0601 and RB0602 are all classified as chemical reaction, the mechanism functions are f(α)=(1− α)2, and the kinetic equations are and . The thermal safety evaluation on the BTATz-CMDB propellants was obtained. With the substitution of 26% RDX by BTATz and with the help of the ballistic modifier in the CMDB propellant formulation, the burning rate can be improved by 89.0% at 8MPa and 47.1% at 22MPa, the pressure exponent can be reduced to 0.353 at 14–20MPa. [Copyright &y& Elsevier]

Abstract: A bismuth 3-nitro-1,2,4-triazol-5-one (Bi-NTO) complex was prepared and characterized, and its effects on the thermal behaviors, non-isothermal decomposition reaction kinetics, and burning rates of the double-base (DB) propellant containing the mixed ester of triethyleneglycol dinitrate (TEGDN) and nitroglycerin (NG) with Bi-NTO complex as a ballistic modifier were investigated by thermogravimetry and derivative thermogravimetry (TG–DTG), and differential scanning calorimetry (DSC). The results show that Bi-NTO complex can increase the decomposition heat by 140Jg−1, and it can change the decomposition reaction mechanism function, the kinetic parameters and kinetic equation of the propellant under 0.1MPa. Combustion experiment shows that Bi-NTO complex can increase the burning rate and reduce the pressure exponent of the NG/TEGDN/NC propellant effectively, with the increase of the catalysis efficiency by 40%. [Copyright &y& Elsevier]

The effects of pressure and triethyleneglycol dinitrate (TEGDN) content on the decomposition reaction mechanism and kinetics of the double-base (DB) gun propellant composed of mixed ester of TEGDN and nitroglycerin (NG), and nitrocellulose (NC) were investigated by high-pressure differential scanning calorimetry (PDSC). The results show that the high pressure can decrease the DSC peak temperature, increase the decomposition heat; with the increase in the content of TEGDN, the decomposition heat decreases below 2MPa and rises at 4MPa. The high pressure can change the decomposition reaction mechanism and the kinetics of the DB gun propellant under 0.1MPa; the high TEGDN content does not change the mechanism functions, and the kinetic equation has a little difference between the sample and the control propellant; the high pressure makes the critical temperature (T be) of thermal explosion of the sample decrease, while the high TEGDN content make it present a increasing trend, and the DB gun propellant containing high content of TEGDN has a better thermal stability. [Copyright &y& Elsevier]

A new high nitrogen compound hydrazine 3-nitro-1,2,4-triazol-5-one complex (HNTO) was prepared by the reaction of 3-nitro-1,2,4-triazol-5-one with hydrazine hydrate, and its structure was characterized by means of organic elemental analyzer, FT-IR, XRD, 13C NMR and 15N NMR. The non-isothermal reaction kinetics of the main exothermic decomposition reaction of HNTO was investigated by means of DSC. The thermodynamic properties of HNTO were calculated. The results showed that the formation of HNTO is achieved by proton transfer of N(4) atom, and it makes a higher nitrogen content and lower acidity. The reaction mechanism of HNTO is classified as nucleation and growth, and the mechanism function is Avramo–Erofeev equation with n =2/5. The kinetic parameters of the reaction are E a =195.29kJmol−1, lg(A (s−1))=19.37, respectively. The kinetic equation can be expressed as:The safety performances of HNTO were carried out. The critical temperature of thermal explosion are 464.26 and 474.37K, the adiabatic time-to-explosion is 262s, the impact sensitivity H 50 =45.7cm, the friction sensitivity P =20% and the electrostatic spark sensitivity E 50 >5.4J (no ignition). It shows that HNTO has an insensitive nature as RDX and NTO, etc. [Copyright &y& Elsevier]

Abstract: The constant-volume combustion energy, (DNTF, s, 298.15K) and kinetic behavior of the exothermic decomposition reaction of the title compound (DNTF) are determined by a precise rotating bomb calorimeter and DSC, respectively. Its standard enthalpy of combustion, (DNTF, s, 298.15K), standard enthalpy of formation, (DNTF, s, 298.15K) and kinetic parameters of the major exothermic decomposition reaction in a temperature-programmed mode [the apparent activation energy (Ea) and pre-exponential factor (A)] are calculated. The values of (DNTF, s, 298.15K), (DNTF, s, 298.15K), and (DNTF, s, 298.15K) of DNTF are -9733.96 ± 8.59Jg-1, -3018.29 ± 2.68kJmol-1, and 657.23 ± 2.70kJmol-1, respectively. The kinetic model function in integral form and the value of Ea and A of the major exothermic decomposition reaction of DNTF are , 177.03kJmol-1 and 1013.68s-1, respectively. The critical temperature of thermal explosion of DNTF is 240.6°C. [Copyright &y& Elsevier]

Coastal waters are complex and dynamic areas with unique environmental attributes that complicate the vertical migration of microplastics (MPs). The MPs that enter coastal waters from diverse sources, including terrestrial, riverine, oceanic, and shoreline inputs undergo various aging pathways. In this study, the variations in the physiochemical characteristics of MPs undergoing various aging pathways and their vertical migration under dynamic conditions subjected to the effects of different MP characteristics and coastal environmental features were comprehensively explored. Opposite effects of aging on the vertical migration of hydrophobic and hydrophilic MPs were observed, with aging appearing to promote the dispersion of hydrophobic MPs but enhance the vertical migration of hydrophilic ones. The positive role of salinity and the negative role of humic acid (HA) concentrations on MP vertical migration were identified, and the mechanisms driving these effects were analyzed. Notably, intense turbulence not only promoted the floating of positively buoyant MPs but also reversed the migration direction of negatively buoyant MPs from downward to upward. Aging-induced changes in MP characteristics had a limited effect on MP vertical migration. The inherent characteristics of MPs and the surrounding environmental features, however, played major roles in their vertical migration dynamics. Microplastics (MPs) have emerged as a significant global environmental concern and the coastal zones are the hotspots for MP pollution due to their high population density. This study comprehensively investigated the variations in the physiochemical characteristics of MPs undergoing various aging pathways. Their vertical migration patterns under dynamic conditions subjected to the effects of different MP characteristics and coastal environmental features were revealed. The roles of turbulence and MP density in their migration were identified. The findings of this study have important implications for understanding the transport and determining the ecological risks of MPs in coastal waters. [Display omitted] • Aging affected hydrophobic and hydrophilic microplastics' migration differently. • The effect of salinity and humic acid was related to microplastic surface charge. • Intense turbulence inverted the migration path of negatively buoyant microplastics. • Strong turbulence disrupted the effect of density on microplastic migration. • Correlation analyses revealed the key factors affecting microplastic migration. [ABSTRACT FROM AUTHOR]

Methyl hydrazine (MMH) is a key ingredient in rocket fuel as well as an important intermediate and solvent in organic synthesis. However, any remaining MMH in environment could be harmful to both people and the environment. In this work, we proposed a method for treating MMH pollution by supercritical water oxidation (SCWO) technology. Reactive molecular dynamics were used to reveal the microscopic mechanism of the oxidation decomposition of MMH. The results showed that the principle of SCWO is that the OH radicals are formed by the reaction between H 2 O and O 2. It can effectively capture the H both in MMH and its decomposition fragments, thus speeding up the decomposition. At low temperature and low oxygen content, the initial decomposition of MMH has two main pathways: (1) CH 3 NHNH 2 → CH 3 NH + NH 2 (R1), and (2) CH 3 NHNH 2 + OH → CH 3 NNH 2 + H 2 O (R7). N 2 , CO 2 , and H 2 O are the final products. At high temperatures, the intermediate NH 3 can be converted to N 2. The activation energy of MMH decomposition with excess oxygen was also obtained by the Arrhenius equation as 29.3 kcal/mol. [Display omitted] • Methylhydrazine (MMH) is rapidly degraded by supercritical water oxidation. • Main transformation pathways of N atom in MMH are proposed. • Four pathways of OH generation in supercritical water oxidation are proposed. • NH3 can be fully converted to N2 under supercritical water oxidation. [ABSTRACT FROM AUTHOR]

A new high-nitrogen compound [Mn(ATZ)(H2O)4]·2H2O (ATZ=5,5-azotetrazolate) was synthesized. Crystal structure and elemental, IR and thermal analyses were investigated in the present work. It crystallized in triclinic space group P-1 with lattice parameters a =6. 304(2)Å, b =7. 004(2)Å, c =7. 921(3)Å, α =76. 114(5)°, β =74. 023(5)°, γ =69. 254(4)°. TG-DTG and DSC measurements are employed to postulate the thermal decomposition mechanism. The thermal decomposition kinetics of the main exothermic reaction was investigated by non-isothermal method and obtained its enthalpy of decomposition and the probable kinetic mechanism. An attempt was made to incorporate the relation between thermal stability and the structure. [Copyright &y& Elsevier]

Biodegradable mulches (BMs) can be tilled into soils to mitigate disposal and environmental problems. However, the content of biodegradable microplastics (BMPs) would increase with the addition of biodegradable macroplastics (BMaPs). The fragmented particles have a strong affinity to soil pollutants, having the potential to transfer via the terrestrial food web in an agroecosystem. Based on the spectral analysis and particle size analysis, this study explored the physicochemical characteristics of weathered BMaPs and BMP-derived dissolved organic matter (DOM BMP). Ultraviolet (UV) irradiation reduced the mechanical strength of BMaPs and induced oxygenated functional groups, thus increasing surface roughness and hydrophilicity. This promoted the adsorption of aromatic compounds and heavy metals from soils to BMPs. After entering the water environment, the pH of the solution with DOM BMP decreased, whereas the concentration of dissolved organic carbon (DOC) increased. Compared with paper mulch, bioplastic mulch contributed a higher amount of DOM BMP , such as aromatic structure-containing chemicals and carboxylic acids, to the water environment but released fewer and smaller plastic particles. The findings from this study can help manage environmental risks and determine disposal strategies after the use of mulching. [Display omitted] • UV irradiation reduced the mechanical strength of biodegradable mulches. • UV irradiation induced oxygenated functional groups and increased hydrophilicity. • UV irradiation promoted the transport of heavy metals from soils to mulch surfaces. • Weathered mulches released microparticles and acid-dissolved organic matter. • Fragmented particles may transfer via the terrestrial food web in agroecosystems. [ABSTRACT FROM AUTHOR]

It is well known that oil stranded on shoreline substrates can be difficult to remove and cause serious environmental effects. To address this issue, a calcium alginate-cellulose nanocrystal (CA-CNC)-based coating with a unique surface structure and superhydrophobic properties was developed to reduce the extent of shoreline oiling. The results of batch washing test showed that not only did the introduction of CNC not reduce the oil removal efficiency; it also improved the environmental stability of the coating to resist the effects associated with seawater immersion and erosion (especially in the case of 0.4 wt% of CNC). The oil-repellent performance of the coated gravels implied that both oscillation time and oil concentration had almost no effects on the amount of adhered oil. Assessment of oiling prevention based on the laboratory shoreline tank simulator proved the coated gravel performed very well as more oil floated and less oil remained on substrates and penetrated into the subsurface. Biotoxicity analysis showed that the coating powders reduced impacts on the toxicity of the oil to algae at low doses. There is a good potential for the use of this CA-CNC based coating technique to improve shoreline oil spill response. [Display omitted] • A calcium alginate-cellulose nanocrystal-based coating approach was developed. • The coated gravels showed good performance of oil removal and repellence. • The coating exhibited environmental stability in immersion and erosion of seawater. • The feasibility of using coating for oiling prevention was proved in tank tests. • Biotoxicity analysis revealed the coating alleviated the toxicity of oil to algae. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nonisothermal decomposition kinetics of RDX and its PBXs has been investigated. [•] The kinetic models are determined by both master plot and combined kinetic analysis methods. [•] The constant rate temperature profiles and isothermal curves are predicted by obtained kinetic triplets. [•] The storage safety parameters are simulated based on thermal explosion theory. [ABSTRACT FROM AUTHOR]

The thermal behavior and decomposition reaction kinetics of 2-nitroimino-5-nitro-hexahydro-1,3,5-triazine (NNHT) were investigated by TG–DTG and DSC under atmospheric pressure and flowing nitrogen gas conditions. The results show that the thermal decomposition process of NNHT has two mass loss stages. The exothermic decomposition reaction mechanism obeys chemical reaction rule. The kinetic parameters of the reaction are E a =131.77kJmol−1, lg(A/s−1)=12.56, respectively. The kinetic equation can be expressed as: . The critical temperature of thermal explosion of NNHT obtained from the peak temperature (T p) is T bp =467.22K. The entropy of activation (ΔS ≠), enthalpy of activation (ΔH ≠), and free energy of activation (ΔG ≠) of the reaction are −7.978Jmol−1 K−1, 127.99kJmol−1 and 131.62kJmol−1, respectively. [Copyright &y& Elsevier]

The COVID-19 pandemic has driven explosive growth in the use of masks has resulted in many issues related to the disposal and management of waste masks. As improperly disposed masks enter the ocean, the risk to the marine ecological system is further aggravated, especially in the shoreline environment. The objective of this study is to explore the changing characteristics and environmental behaviors of disposable masks when exposed to the shoreline environment. The transformation of chain structure and chemical composition of masks as well as the decreased mechanical strength of masks after UV weathering were observed. The melt-blown cloth in the middle layer of masks was found to be particularly sensitive to UV irradiation. A single weathered mask can release more than 1.5 million microplastics to the aqueous environment. The physical abrasion caused by sand further exacerbated the release of microplastic particles from masks, with more than 16 million particles released from just one weathered mask in the presence of sand. The study results indicate that shorelines are not only the main receptor of discarded masks from oceans and lands, but also play host to further transformation of masks to plastic particles. [Display omitted] • Disposable masks are widely observed on shorelines during the pandemic. • Physicochemical features of disposable masks changed dramatically under UV weathering. • The transformation of chain structure and decreased mechanical strength were observed. • Masks can be broken into small pieces, releasing a large quantity of microplastics. • Around 1.5 million particles can be released from a disposable mask after weathering. [ABSTRACT FROM AUTHOR]