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Incorporation of a Boron-Nitrogen Covalent Bond Improves the Charge-Transport and Charge-Transfer Characteristics of Organoboron Small-Molecule Acceptors for Organic Solar Cells
No full textAn organoboron small-molecular acceptor (OSMA) M-B <- N containing a boron-nitrogen coordination bond (B <- N) exhibits good light absorption in organic solar cells (OSCs). In this work, based on M-B <- N, OSMA MB-N, with the incorporation of a boron-nitrogen covalent bond (B-N), was designed. We have systematically investigated the charge-transport properties and interfacial charge-transfer characteristics of MB-N, along with M-B <- N, using the density functional theory (DFT) and the time-dependent density functional theory (TD-DFT). Theoretical calculations show that MB-N can simultaneously boost the open-circuit voltage (from 0.78 V to 0.85 V) and the short-circuit current due to its high-lying lowest unoccupied molecular orbital and the reduced energy gap. Moreover, its large dipole shortens stacking and greatly enhances electron mobility by up to 5.91 x 10(-3) cm(2)Greek ano teleiaV(-1)Greek ano teleias(-1). Notably, the excellent interfacial properties of PTB7-Th/MB-N, owing to more charge transfer states generated through the direct excitation process and the intermolecular electric field mechanism, are expected to improve OSCs performance. Together with the excellent properties of MB-N, we demonstrate a new OSMA and develop a new organoboron building block with B-N units. The computations also shed light on the structure-property relationships and provide in-depth theoretical guidance for the application of organoboron photovoltaic materials
CFD simulation of liquid holdup in a three-phase countercurrent turbulent contact absorber
No full textCFD study of a turbulent contact absorber (TCA) for Type I and Type II regimes is performed where Eulerian approach is used with closures from using Kinetic Theory of Granular Flow (KTGF). Liquid holdup (LHU), expanded bed height (EBH) and bed pressure drop were calculated to compare simulation results with experi-mental data. It is found that CFD can be used confidently to calculate these variables. EBH for Type I regime is more than Type II regime with increasing gas velocity. Slight increase in the EBH is noted with increase in liquid velocity for both regimes. LHU and pressure drop is remains almost constant for all gas velocity, but increases with increasing liquid velocity. It is concluded that the results of EBH, pressure drop, and LHU are in close agreement with the experimental findings. Simulation results are in better agreement with experiments as compared to the results predicted by relevant correlations
Porous multi-site ionic liquid composites for superior selective and reversible adsorption of ammonia
No full textIonic liquids (ILs) with low vapor pressure, tunable structures and good NH3 affinity provide an inspiring way to efficiently capture NH3. However, the high viscosity of most ILs limited mass transfer, which incumbers their industrial applications. Besides, how to simultaneously achieve high selectivity, capacity and reversibility of NH3 still face great challenge. Herein, four novel hydroxyl ammonium protic ILs (HAPILs), including methyl-diethanolammonium trifluoromethanesulfonate ([MDEAH][CF3SO3]), triethanolammonium tri-fluoromethanesulfonate ([TEAH][CF3SO3]), dimethylethanolammonium trifluoromethanesulfonate ([DMEAH] [CF3SO3]) and diethylethanolammonium trifluoromethanesulfonate ([DEEAH][CF3SO3]), with multiple hydrogen bonding donors that can interact with more over two NH3 molecules were designed and synthesized, and were further supported onto porous molecular sieves to overcome the above problem. Among the prepared porous HAPIL composites, 50 wt% [TEAH][CF3SO3]@MCM-41 showed the highest NH3/CO2 selectivity of 62 under 313 K and 0.1 MPa compared with the state-of-the-art values, along with high capacity of 114.3 mgNH3/g-adsorbent. The excellent NH3 adsorption performance was attributed to the synergistic interaction of mesoporous effect and multiple hydrogen bonding between NH3 and HAPILs. Furthermore, the porous HAPIL composites exhibited great recyclability after six cycles, revealing great potentials in industrial application of efficient and reversible NH3 separation
Ionic Microporous Polymer Membranes for Advanced Gas Separations
No full textMicroporous polymers are uniquely attractive for membrane-mediated gas separations; however, conventional microporous polymers suffer a ubiquitous trade-off between gas permeability and selectivity, leading to bottlenecks in their practical applications. Functionalization of microporous polymers via molecule engineering is an effective way to enhance their gas separation performance and processability. This review outlines the research progress of ionization to improve the gas separation performance of typical microporous polymers (e.g., polymers of intrinsic microporosity (PIM), perfluorinated polymers, microporous polyimides, etc.) and summarizes the different ionization methods, including carboxylation, sulfonation, quaternization, and other ionization processes. Additionally, the review also explores the research progress of ionization to regulate the processability, microporosity, and gas separation properties of microporous polymers. Specifically, ionization can effectively tailor the microporosity, improve the solubility coefficients of gas molecules, especially CO2, and enhance gas selectivities. In addition, ionization can improve the processability of PIMs and enhance the membrane plasticization resistance. Ionic microporous polymers provide an essential platform for developing energy-efficient and high-performance gas separation membranes
Red mud recycling by Fe and Al recovery through the hydrometallurgy method: a collaborative strategy for aluminum and iron industry
No full textIn this work, a collaborative strategy for the aluminum and iron industry based on red mud recycling through the hydrometallurgy method was proposed. In this method, Fe3+ and Al3+ were firstly separated from the red mud by using H2SO4 as a leaching agent, which was by-produced from the sintering process of an iron and steel industry. Multiple influence factors on the leaching process were investigated, with the H2SO4 addition amount showing the strongest influence on the leaching rates of Al and Fe. The main components of the filter residue were CaSO4, TiO2, and SiO2, which could be reused as additives in the building materials. Subsequently, the final Fe recovery product was obtained through the co-precipitation, Fe/Al separation, and Fe(OH)(3) calcination. In the final product, the content of Fe2O3 reached 82.87%, and the iron grade was 58.01%, meeting the requirement being raw materials for sinter production
Sulfidated microscale zero-valent iron/reduced graphene oxide composite (S-mZVI/rGO) for enhanced degradation of trichloroethylene: The role of hydrogen spillover
No full textAtomic hydrogen (H*) has long been thought to play an important role in the dechlorination of trichloroethylene (TCE) by carbon-supported zero-valent iron (ZVI), which offers an alternative pathway for TCE dechlorination. Herein, we demonstrate that the reductive dechlorination of TCE by sulfidated microscale ZVI (S-mZVI) can be further enhanced by promoting the formation of H* through the introduction of reduced graphene oxide (rGO). The completely degradation of 10 mg/L TCE can be achieved by S-mZVI/rGO within 24 h, which was 3.3 times faster than that of S-mZVI. The change in the distribution of TCE degradation products over time suggests that the introduction of rGO leads to a change in the dechlorination pathway. The percentage of ethane in the final products of TCE degradation by S-mZVI/rGO was 34.3 %, while that of S-mZVI was only 21.9 %. The electrochemical tests confirmed the occurrence of hydrogen spillover in the S-mZVI/rGO composite, which promoted the reductive dechlorination of TCE by H*. Although the S-mZVI/rGO composite had stronger hydrogen evolution propensity than S-mZVI, the S-mZVI/rGO composite still exhibited higher electron utilization efficiency than S-mZVI thanks to the increased utilization of hydrogen
