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The enhanced surface mobility in metallic glasses (MGs) has been a constant source of fascination due to its unique mechanical properties. We show experimentally that the mobile surface layer of MGs functions as a lubricating layer in friction experiments, which is evidenced by a reduction of a friction coefficient of 50% or less and suppression of dissipative stick-slip behavior with decreasing scratch depth down to nanoscale in the various MGs. The lubrication mechanism could be attributed to easier shearing of the mobile surface layer induced by homogeneous plastic flow. Importantly, the thickness of the self-lubricating layer is inversely proportional to glass transition temperature with a higher homologous temperature yielding a larger thickness. These results extend the fundamental understanding of the ubiquitous MG surface and present a path for the rational design of self-lubricating materials. [ABSTRACT FROM AUTHOR]

Understanding the ecological relationship of microbial community under external stimulation is crucial for environmental restoration. Black carbon (e.g., biochar) have been widely deemed as a strategy to enhance pollutants removal because of its structure and redox-active property. However, the underlying ecological mechanism of microbial community under black carbon addition is poorly understood. The major purposes of this study were to determine the microbial assemblage and functional patterns via null model test, network analysis, and function prediction. The results showed that the nitrate removal efficiency of modified black carbon system achieved 46.44%. Both deterministic and stochastic processes were significant for mediating the microbial assemblage and the deterministic process dominated (>95%) the assemblage of community. Keystone taxa in the black carbon systems, involving Sulfuricella , Allorhizobium , and Nitrospira , stimulated the shift of community composition regarding the nitrogen removal. The existence of black carbon and the biotic interactions increased biological nitrate utilization and promoted nitrogen removal. Overall, this study presents the mechanism of bacterial community assembly and provides insight into biological nitrogen removal from microbial ecological perspective. Image 1 • Both deterministic and stochastic processes affect community assembly. • Black carbon alters the composition and function of the microbial community. • The maximal information coefficient was used to build co-occurrence network. • The biotic factor keystone taxa influenced nitrogen removal. [ABSTRACT FROM AUTHOR]

• The promotion of graphene derivative on biological nitrogen removal was explored. • The interaction between stochastic assembly and deterministic assembly intensified. • Keystone taxa include S ulfuricella , Rhodobacter, and Comamonadaceae. • Keystone act as drivers in the graphene derivative-mediated community assembly. Understanding the underlying mechanism that drives the microbial community mediated by graphene derivative is crucial for achieving the enhancement of biological nitrogen removal by external stimulation. The main objectives of this study were to identify the bacterial community assembly mechanism via null model test and molecular ecological network analysis in the sediment culture system. Results showed graphene derivative increased biological nitrogen removal efficiency by 125%. The high electron transfer efficiency and denitrifying enzyme activities were achieved. Deterministic assembly is dominate (>90%) in all the community assembly while the stochastic assembly process only existed in graphene derivative system (6.67%). The nitrogen removal was enhanced due to the intensification of the interaction on the microbial community between stochastic assembly and deterministic assembly. Keystone taxa in the graphene derivative systems, including Sulfuricella , Rhodobacter , and Comamonadaceae , drove the alteration of community structure relating to the nitrogen removal. [ABSTRACT FROM AUTHOR]

Static magnetic field (SMF) with the intensity of 15 mT was applied during partial nitrification (PN) process to evaluate the impacts on nitrogen transformation and microbial characteristics. Results showed that the startup period of PN process at ambient temperature was markedly shortened by SMF, and the nitrite accumulation increased by 18% due to SMF exposure. The ammonia oxidizing bacteria (AOB) amoA gene copy numbers in the reactor with SMF exposure were 40% higher than that without SMF exposure, indicating the AOB abundance was enriched by SMF exposure. The characteristics of extracellular polymeric substances (EPS) changed accordingly. The extracellular protein increased by 30% due to SMF exposure, and it favored the aggregation of sludge flocs. The activated sludge with SMF exposure had a more compact structure, which was in favor of partial nitrification. [ABSTRACT FROM AUTHOR]

• COSMO-RS is used for screening > 103 ILs with highly efficient in lignin dissolving. • Calculations and experiment prove the dissolving of IL is mainly modulated by H-bond. • [PMpyrr][OAC] ILs with the ability to dissolve lignin strongly. • The solubility of lignin in IL is related to the structure of lignin model. As the second most abundant terrestrial polymer, lignin has emerged as a major sustainable source for the production of fuels, chemicals, and materials. However, efficient screening of solvents for lignin dissolving faces great challenges. In this work, COSMO-RS was used to screen 3886 ionic liquids (ILs) composed of 58 cations and 67 anions, to find out the most effective ones for lignin dissolving by considering the critical items of logarithmic infinite dilution activity coefficient (lnγ∞) and σ-profiles. The substantial improvement of lignin dissolution was achieved in [PMpyrr][OAc] IL by both simulations and experiments validations. Moreover, it was found that the anions dominate the dissolution process and the strongly polar anions exhibit better dissolution ability. Furthermore, the underlying mechanism originated from the hydrogen bond (H-bond) between ILs and lignin was also revealed and systemically analyzed from donor and acceptor ability, indicating that high lignin solubility is reached in the ILs with stronger ability to form H-bond acceptors. This work leads to possible ways toward developing more selective and efficient lignin dissolution methods based on solvent properties. [ABSTRACT FROM AUTHOR]

• Summarizing experimental preparation of two-dimensional ionic liquid membranes. • Clarifying molecular mechanism of CO 2 separation in two-dimensional ionic liquid membranes. • Prospecting challenges and strategies for the two-dimensional nanoconfined ionic liquid membranes. The realization of efficient and stable carbon dioxide (CO 2) separation technology holds profound significance for the development of green chemistry. In comparison with other CO 2 separation technologies, membrane separation technology has the advantages of low energy consumption and simple operation. When used in conjunction with gas separation membranes, ionic liquids are always placed into the nanochannel constructed by two-dimensional nanosheets, forming the nanoconfined ionic liquid membrane (NC-ILM), which has exhibited excellent CO 2 separation performance with high permeation and selectivity. In this review, we have summarized the structure and properties of nanoconfined ILs, the separation mechanism, and investigated methods of NC-ILMs, further discussing the challenges and strategies for the future application of NC-ILMs. Those results on the NC-ILMs not only can deepen the understanding of the molecular mechanism of separating CO 2 but also promote the preparation technology of the related membrane with precise nanochannels. [ABSTRACT FROM AUTHOR]

• Saturated cyclic cations interact more strengthened with anions than unsaturated cations. • Electrostatics effect is the dominated factor in determining ion binding. • H-bond in saturated cations based ILs is stronger than that in unsaturated cations. In this work, we have investigated the intermolecular interaction and hydrogen bond (H-bond) strength of unsaturated and saturated cations of ionic liquids (ILs) ([EMIM]+, [Epy]+, [Epr]+, and [Epp]+) with Cl-, [BF 4 ]-, [DCA]-, and [OAC]- anions, for the aim of determining how is the influence of the unsaturated and saturated cations on the ion binding. Via molecular dynamic simulations and density functional theory calculations, it is found that saturated [Epr]+ and [Epp]+ manifest the strongest binding energies with Cl- and [OAC]-, where electrostatics effect overwhelms the induction and dispersion effects, as the dominant factor determining ion binding. On the other hand, the resolution of H-bond strength in ion-pair implies that it is stronger in [Epr]+ and [Epp]+ based ILs, especially the strongest when they pair with Cl-. Our results verify that saturated heterocycle-based cations serve as stronger anion binding sites and stronger H-bond donors than unsaturated ones, and that such ILs can be potentially applied in areas with specific demanding with strong ion binding. [ABSTRACT FROM AUTHOR]