This work is aimed to study in situ upgrading of Shengli lignite pyrolysis vapors over different metal-loaded HZSM-5 in a drop tube reactor. Co/HZSM-5, Mo/HZSM-5 and Ni/HZSM-5 (5.0wt%) were prepared ...by wet impregnation and characterized by N2 adsorption-desorption analyzer, X-ray diffraction, transmission electron microscope, Fourier transform infrared spectrometer and temperature programmed desorption of ammonia. The effects of temperature and catalyst on product yields and tar properties were investigated. The results show that the optimal temperature for liquid product was 600°C and aromatics can be directly produced from solid lignite by catalytic fast pyrolysis over metal-loaded HZSM-5 under such mild condition. Due to the participation of metal and acid sites, the bifunctional metal-loaded HZSM-5 showed comparable catalytic activity for deoxygenation reaction in the valorization of oxygen content below 7.1%. The introduction of metal causes the increase of aromatics and the decrease of organic oxygen species in upgraded tar remarkably. Among the catalysts, Ni/HZSM-5 exhibited the best performance for production of high quality tars with highest aromatics content of 94.2% (area%), which can be used as a potential candidate for catalytic upgrading of pyrolysis oil.
•Metal-loaded HZSM-5 was prepared for conversion of lignite to light aromatics.•The BTEXN formation was enhanced by metal-loaded HZSM-5.•Oxygen content in pyrolysis tar is remarkably decreased by metal-loaded HZSM-5.•Ni-loaded HZSM-5 is a potential candidate in catalytic upgrading of pyrolysis oil.
Supported ionic liquid membranes (SILMs), owing to their capacities in harnessing physicochemical properties of ionic liquid for exceptional CO2 solubility, have emerged as a promising platform for ...CO2 extraction. Despite great achievements, existing SILMs suffer from poor structural and performance stability under high‐pressure or long‐term operations, significantly limiting their applications. Herein, a one‐step and in situ interfacial polymerization strategy is proposed to elaborate a thin, mechanically‐robust, and highly‐permeable polyamide armor on the SILMs to effectively protect ionic liquid within porous supports, allowing for intensifying the overall stability of SILMs without compromising CO2 separation performance. The armored SILMs have a profound increase of breakthrough pressure by 105% compared to conventional counterparts without armor, and display high and stable operating pressure exceeding that of most SILMs previously reported. It is further demonstrated that the armored SILMs exhibit ultrahigh ideal CO2/N2 selectivity of about 200 and excellent CO2 permeation of 78 barrers upon over 150 h operation, as opposed to the full failure of CO2 separation performance within 36 h using conventional SILMs. The design concept of armor provides a flexible and additional dimension in developing high‐performance and durable SILMs, pushing the practical application of ionic liquids in separation processes.
A thin, mechanically‐robust, and highly‐permeable polyamide armor is designed and manufactured on the supported ionic liquid membranes (SILMs) via one‐step and in situ interfacial polymerization, fundamentally resolving poor structural and performance stability of the SILMs. The armored SILMs display high operating pressure exceeding most SILMs, and ultrahigh CO2/N2 selectivity of about 200 and excellent CO2 permeation even upon over 150 h operation.
Designing nanocomposite hydrogels with oriented nanosheets has emerged as a promising toolkit to achieve preferential performances that go beyond their disordered counterparts. Although current ...fabrication strategies via electric/magnetic force fields have made remarkable achievements, they necessitate special properties of nanosheets and suffer from an inferior orientation degree of nanosheets. Herein, a facile and universal approach is discovered to elaborate MXene‐based nanocomposite hydrogels with highly oriented, heterogeneous architecture by virtue of supergravity to replace conventional force fields. The key to such architecture is to leverage bidirectional, force‐tunable attributes of supergravity containing coupled orthogonal shear and centrifugal force field for steering high‐efficient movement, pre‐orientation, and stacking of MXene nanosheets in the bottom. Such a synergetic effect allows for yielding heterogeneous nanocomposite hydrogels with a high‐orientation MXene‐rich layer (orientation degree, f = 0.83) and a polymer‐rich layer. The authors demonstrate that MXene‐based nanocomposite hydrogels leverage their high‐orientation, heterogeneous architecture to deliver an extraordinary electromagnetic interference shielding effectiveness of 55.2 dB at 12.4 GHz yet using a super‐low MXene of 0.3 wt%, surpassing most hydrogels‐based electromagnetic shielding materials. This versatile supergravity‐steered strategy can be further extended to arbitrary nanosheets including MoS2, GO, and C3N4, offering a paradigm in the development of oriented nanocomposites.
A novel supergravity‐steered approach is designed to manipulate the assembly of arbitrary nanosheets from MXene to MoS2, GO, and C3N4 for fabricating oriented nanocomposite hydrogels with heterogeneous architecture. The resultant MXene‐based nanocomposite hydrogels showcase an extraordinary electromagnetic interference shielding effectiveness (EMI SE) of 55.2 dB yet using a super‐low MXene of 0.3 wt%, surpassing most hydrogels‐based electromagnetic shielding materials.
It is particularly essential to analyze the complex crosslinked networks within polyamide membranes and their correlation with separation efficiency for the insightful tailoring of desalination ...membranes. However, using the degree of network crosslinking as a descriptor yields abnormal analytical outcomes and limited correlation with desalination performance due to imperfections in segmentation and calculation methods. Herein, we introduce a more rational parameter, denoted as harmonic amide bond density (HABD), to unravel the relationship between the crosslinked networks of polyamide membranes and their desalination performance. HABD quantifies the number of distinct amide bonds per unit mass of polyamide, based on a comprehensive segmentation of polyamide structure and consistent computational protocols derived from X-ray photoelectron spectroscopy data. Compared to its counterpart, HABD overcomes the limitations and offers a more accurate depiction of the crosslinked networks. Empirical data validate that HABD exhibits the expected correlation with the salt rejection and water permeance of reverse osmosis and nanofiltration polyamide membranes. Notably, HABD is applicable for analyzing complex crosslinked polyamide networks formed by highly functional monomers. By offering a powerful toolbox for systematic analysis of crosslinked polyamide networks, HABD facilitates the development of permselective membranes with enhanced performance in desalination applications.
The deepening crisis of freshwater resources has been driving the further development of new types of membrane-based desalination technologies represented by nanofiltration membranes. Solving the ...existing trade-off limitation on enhancing the water permeance and the rejection of salts is currently one of the most concerned research interests. Here, a facile and scalable approach is proposed to tune the interfacial polymerization by constructing a calcium alginate hydrogel layer on the porous substrates. The evenly coated thin hydrogel layer can not only store amine monomers like the aqueous phase but also suppress the diffusion of amine monomers inside, as well as provide a flat and stable interface to implement the interfacial polymerization. The resultant polyamide nanofilms have a relatively smooth morphology, negatively charged surface, and reduced thickness which facilitate a fast water permeation while maintaining rejection efficiency. As a result, the as-prepared composite membranes show improved water permeance (~30 Lm−2h−1bar−1) and comparable rejection of Na2SO4 (>97%) in practical applications. It is proved to be a feasible approach to manufacturing high-performance nanofiltration membranes with the assist of alginate hydrogel regulating interfacial polymerization.
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Directional sweat-wicking by Janus fabrics has gained substantial attention in promoting personal wet-thermal management for optimal human comfort. During intense physical exercise, ...excessive sweating can cause the flooding of fabrics and weaken their wicking capabilities once the inner capillary channels are saturated. To address this issue, we develop a photothermal Janus fabric through a facile polydopamine (PDA) deposition followed by single-sided spray-coating of hydrophobic polydimethylsiloxane (PDMS). Such innovative fabrics enable directional sweat-wicking through a Janus structure and persistent removal of excessive sweat by solar-powered evaporation. Under sunlight, our photothermal Janus fabrics exhibit an enhanced evaporation rate, approximately twice compared with that of conventional Janus fabrics (∼1.143 ± 0.027 kg m-2h−1), making them suitable for high sweating rates during vigorous exercise. Furthermore, these fabrics help to maintain the skin temperature within the normal range, preventing hypothermia caused by profuse sweating. In addition, our photothermal Janus fabrics exhibit excellent washing durability even after multiple washing cycles, ensuring prolonged performance and safety.
Supported ionic liquid membranes (SILMs), owing to their capacities in harnessing physicochemical properties of ionic liquid for exceptional CO
solubility, have emerged as a promising platform for CO
...extraction. Despite great achievements, existing SILMs suffer from poor structural and performance stability under high-pressure or long-term operations, significantly limiting their applications. Herein, a one-step and in situ interfacial polymerization strategy is proposed to elaborate a thin, mechanically-robust, and highly-permeable polyamide armor on the SILMs to effectively protect ionic liquid within porous supports, allowing for intensifying the overall stability of SILMs without compromising CO
separation performance. The armored SILMs have a profound increase of breakthrough pressure by 105% compared to conventional counterparts without armor, and display high and stable operating pressure exceeding that of most SILMs previously reported. It is further demonstrated that the armored SILMs exhibit ultrahigh ideal CO
/N
selectivity of about 200 and excellent CO
permeation of 78 barrers upon over 150 h operation, as opposed to the full failure of CO
separation performance within 36 h using conventional SILMs. The design concept of armor provides a flexible and additional dimension in developing high-performance and durable SILMs, pushing the practical application of ionic liquids in separation processes.
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•Polyamide nanofilms around 10 nm are facilely synthesized by a scalable process.•A sequential process of coating-spraying-interfacial polymerization is developed.•Organic solvent ...consumption reduces by 99 % compared with conventional process.•The polyamide nanofilms represent high performance as desalination membranes.
Thin film composite (TFC) membranes composed of polyamide nanofilms and porous substrates have received enhancing attention to desalination for overcoming the nexus of serious scarcity and huge demand for fresh water. Up to now, it is still a big challenge to avoid the complex interference of the porous substrates on the interfacial polymerization of amine and acyl chloride monomers for synthesizing polyamide nanofilms at lower carbon footprint. Herein, we report a sequential process of blade coating–spraying–interfacial polymerization for scalable preparation of polyamide nanofilms that shine in high-performance desalination. Our sequential process consists of 1) blade coating the viscous solution of water/glycerol/m-phenylenediamine (MPD) to form an anti-interference aqueous film, 2) spaying the organic solution of Isopar H/trimesoyl chloride (TMC) under a controlled and economical way onto the water/glycerol/MPD film, and 3) conducting the interfacial polymerization of MPD and TMC at the constructed organic-aqueous interface. The whole process highly reduces the utilization of organic solvents to meet the demands of lower carbon footprint. The synthesized polyamide nanofilms exhibit extremely low roughness and 10 nm thickness in an area larger than 200 cm2, which can be composited with various porous substrates. The as-prepared TFC membranes represent a high desalination performance of water permeance of 1.89 L m−2 h−1 bar−1 with 97.4% NaCl rejection. Our strategy broadens the way to large-scale synthesis of polyamide nanofilms for high-efficiency desalination membranes.
HZSM-5 was modified via alkaline treatment and wet impregnation method which loading transition metals (Co, Mo–Co and Ni–Co). The performance of catalysts for the catalytic fast pyrolysis of lignite ...was tested in a drop tube reactor at 600 °C. In comparison to non-catalytic experiment, the chemical composition of upgrading tar was obviously simplified, which mainly contains light aromatics such as benzene, toluene, ethylbenzene, xylene and naphthalene (BTEXN). The yield of BTEXN was significantly increased from 12.9 to 26.4 mg/g when Ni/Co-H-5 was used. Meanwhile, the Ni/Co-H-5 treated by NaOH solution achieved considerable deoxygenation performance (86.6%) than other ones. The addition of bimetallic Mo–Co or Ni–Co significantly enhanced the BTEXN selectivity of HZSM-5. Ni promoted H2 formation in gaseous product and caused the decrease of naphthalenes yield. Whereas the yields of toluene and o-xylene increased after the pyrolysis vapors pass through Mo/Co-H-5. The zeolite treated by NaOH solution (AT-HZSM-5) favors the generation of aromatics and phenolics, conversely naphthalene derivatives. Moreover, AT-Mo/Co-H-5 and AT-Ni/Co-H-5 inhibited the coke formation. A catalytic pathway was also proposed to describe the diffusion process of pyrolysis vapors on the active site of catalyst.
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