Chlorinated organic hazardous wastes (COHW) from the chemical industry threaten human health and environment due to persistent toxicity and resistance to degradation. Conventional treatments often suffer from incomplete degradation or poor resource recovery. This work proposed an efficient COHW conversion to ethylene (C2H4) for dual COHW treatment and chemical production. Tetrachloroethylene (C2Cl4), a representative of COHW, was selected to develop a hydrogen thermal plasma pyrolysis reaction kinetic model, which was validated through experiments. The particle evolution in the reactor was investigated, and the cascade reaction pathway of C2Cl4 => acetylene (C2H2) => C2H4 was unveiled, providing a theoretical foundation for product composition regulation. To address the trade-off between low carbon black (C(B)) formation and high C2H4 selectivity in the pyrolysis with conventional single-stage quenching, a novel two-stage quenching strategy was proposed: rapid quenching (above 1300K) suppresses C2H2 to C(B) conversion, followed by appropriate slow quenching (below 1300K) intensifying C2H2 hydrogenation to C2H4. This coupling enhances the C2H4 selectivity and yield. The optimized experiments achieved 100% chlorine removal, a C(B) yield reduction of 94%, a C2H4 selectivity of 43.3%, and a C2H4 yield of 40.2%, making a 110% improvement over single-stage quenching and surpassing all reported COHW-derived C2H4 yields.

The production of medical waste (MW) is a growing concern, particularly in light of the increasing annual generation and the exacerbating effects of the COVID-19 pandemic. Traditional techniques such as incineration and landfilling present significant limitations. In this study, a self-designed 50 kW arc plasma reactor was employed to conduct gasification experiments on nitrile-butadiene rubber (NBR) which served as a model of MW and a mixture of NBR/SiO2 which served as a model of glass-containing MW, using CO2 as the working gas. The CO2 thermal plasma gasification process not only ensures the safe and efficient disposal of MW, but also facilitates its effective conversion into H2 and CO, achieving a carbon conversion efficiency of 94.52%. The yields of H2 and CO reached 98.52% and 81.83%, respectively, and the specific energy consumption was as low as 3.55 kW center dot h center dot kg-1. Furthermore, the addition of SiO2 was found to inhibit the gasification of NBR and cause damage to the reactor. Therefore, it is recommended that glass waste should be removed prior to the treatment of MW. The CO2 thermal plasma gasification technology can not only eliminate environmental and health risks posed by MW, but also convert it into syngas for further utilization. This provides a promising approach to the harmless and resource disposal of MW, while also contributing to the comprehensive utilization of greenhouse gases. (c) 2025 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

AbstractThe efficient removal of low‐concentration components from homologous mixtures is often hampered by the co‐directional effect of traditional thermodynamic regulation approaches, typically leading to a trade‐off between adsorption capacity and selectivity. Focusing this challenge on the critical task of purifying perfluorocarbons in electronics industry, a divergent regulation strategy is reported that significantly improves the separation efficiency of low‐concentration hexafluoroethane (C2F6) from tetrafluoromethane (CF4). This approach involves the selective shielding of open metal sites and the modulation of channel geometry within an electron‐deficient ligand‐based pore environment, thereby facilitating a C2F6 dense‐packing accommodation mode while weakening the CF4 affinity due to the reduced host‐guest interactions. Simultaneously enhanced C2F6 adsorption and reduced CF4 adsorption are achieved, resulting in record‐high low‐pressure C2F6 uptake and C2F6/CF4 selectivity. Comprehensive insights into the unique separation mechanism are illustrated through a combination of solid‐state MAS nuclear magnetic resonance (SSNMR), molecular simulations, and meticulously designed comparative experiments. As a result, benchmark C2F6/CF4 separation performance is achieved, as demonstrated by the unprecedented electronic‐grade (over 99.999%) CF4 productivity (401 L kg−1) obtained from an industrially relevant C2F6/CF4 (3:97) mixture, as well as the excellent water/air/heat stability and recyclability.

Improving the gas separation performance of metal-organic frameworks (MOFs) by crystal downsizing is an important but often overlooked issue. Here, we report three different-sized flexible ZUL-520 MOFs (according to the crystal size from large to small, the three samples are, respectively, named ZUL-520-0, ZUL-520-1, and ZUL-520-2) with the same chemical structure for optimizing trace acetylene (C2H2) removal from acetylene/ethylene (C2H2/C2H4) mixture. The three differently sized activated ZUL-520 (denoted as ZUL-520a) exhibited almost identical C2H2 uptake of 4.8 mmol/g at 100 kPa, while the C2H2 uptake at 1 kPa increased with a downsizing crystal. The C2H2 uptake of activated ZUL-520-2 (denoted as ZUL-520-2a) at 1 kPa was similar to 55% higher than that of activated ZUL-520-0 (denoted as ZUL-520-0a). The adsorption isotherms and adsorption kinetics validated that gas adsorptive separation is governed not only by adsorption thermodynamics but also by adsorption kinetics. In addition, all three different-sized ZUL-520a MOFs showed high C2H2/C2H4 selectivity. Grand canonical Monte Carlo (GCMC) simulations and dispersion-corrected density functional theory (DFT-D) computations illustrated a plausible mechanism of C2H2 adsorption in MOFs. Importantly, breakthrough experiments demonstrated that ZUL-520a can effectively separate the C2H2/C2H4 (1/99, v/v) mixture and the C2H4 productivity obtained by ZUL-520-2a was much higher than that by ZUL-520-0a. Our work may provide an easy but powerful strategy for upgrading the performance of gas adsorptive separation in MOFs.

Efficient separation and purification of xenon (Xe) from krypton (Kr) represent an industrially crucial but challenging process. While the adsorption-based separation of these atomic gases represents an energy-efficient process, achieving highly selective adsorbents remains a difficult task. Here, we demonstrate a supramolecular assembly of coordination polymers, termed as M(II)-dhbq (M = Mg, Mn, Co, and Zn; dhbq = 2,5-dihydroxy-1,4-benzoquinone), with high-density open metal sites (5.3 nm-3) and optimal pore size (5.5 Å), which are able to selectively capture Xe among other chemically inert gases including Kr, Ar, N2, and O2. Among M(II)-dhbq materials, Mn-dhbq exhibits the highest Xe uptake capacity of 3.1 mmol/g and a Xe/Kr selectivity of 11.2 at 298 K and 1.0 bar, outperforming many state-of-the-art adsorbents reported so far. Remarkably, the adsorption selectivity of Mn-dhbq for Xe/O2, Xe/N2, and Xe/Ar at ambient conditions reaches as high as 70.0, 139.3, and 64.0, respectively. Direct breakthrough experiments further confirm that all M(II)-dhbq materials can efficiently discriminate Xe atoms from other inert gases. It is revealed from the density functional theory calculations that the strong affinity between Xe and the coordination polymer is mainly attributed to the polarization by open metal sites.

Adsorptive separation of xenon (Xe) and krypton (Kr) is a promising technique but remains a daunting challenge since they are atomic gases without dipole or quadruple moments. Herein we report a strategy for fabricating angular anion-pillared materials featuring shell-like Xe nano-traps, which provide a cooperative effect conferred by the pore confinement and multiple specific interactions. The perfect permanent pore channel (4-5 angstrom) of Ni(4-DPDS)(2)MO4 (M= Cr, Mo, W) can host Xe atoms efficiently even at ultra-low concentration (400 ppm Xe), showing the second-highest selectivity of 30.2 in Ni(4-DPDS)(2)WO4 and excellent Xe adsorption capacity in Ni(4-DPDS)(2)CrO4 (15.0 mmolkg(-1)). Crystallography studies and DFT-D calculations revealed the energy favorable binding sites and angular anions enable the synergism between optimal pore size and polar porosity for boosting Xe affinity. Dynamic breakthrough experiments demonstrated three MOFs as efficient adsorbents for Xe/Kr separation.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Selective capture and separation of methane (CH4) from nitrogen (N-2) is a feasible approach to mitigate the effects of global warming and to improve the heating value of low-quality natural gas. However, the efficient separation of CH4/N-2 is a challenge issue since their very close kinetic diameters and thermodynamic properties. In this work, a new type of two-dimensional (2D) layered metal-organic framework (MOF) with permanent rhomboid pore channels, denoted as Ni(4-DPDS)(2)CrO4, (4-DPDS = 4,4'-dipyridyldisulfide) was synthesized for the first time and used for CH4/N-2 separation. This novel 2D MOF not only performs high stability as outstanding as or even better than previously reported 3D MOFs but also exhibits a relatively high CH4 adsorption capacity of 0.95 mmol/g. Ni(4-DPDS)(2)CrO4 has a high affinity towards CH4 with the highest reported Q(st) value of 28.4 kJ/ mol as well as a high CH4/N-2 selectivity of 7.3, which is comparable to the state-of-the-art MOF materials reported so far. DFT calculations revealed the energy favorable binding sites for methane molecules are located in the middle of the cavity decorated with CrO42- anion. Such an angular inorganic anion provides polar sites and makes guest-host interactions in close proximity, affording tight binding affinity. Breakthrough experiments and regenerability tests suggest it is a promising material in natural gas purification.

塑料产量增加以及废弃塑料的不合理处置造成了白色污染等环境问题.开发废弃塑料的新型转化途径,实现塑料的升级利用是解决目前危机的关键.通过化学手段选择性断裂聚烯烃塑料中的C—C键,实现向燃油等高附加值产品的转化是一种非常有潜力的方案.本文重点汇总归纳了将聚烯烃塑料催化裂化为高附加值燃料的主要方法,包括催化热解、加氢催化、光催化,着重探讨了催化剂种类,催化剂活性位点、结构对产物碳数分布的影响.鉴于塑料裂解发展现状以及当前存在的反应条件严苛、产物选择性不可控、催化剂昂贵等问题,提出未来应致力于开发新型催化剂和反应机理研究.

己烷异构体的高效分离是石化行业生产高辛烷值汽油的关键过程之一.己烷异构体分子的化学性质不活泼,极化率、沸点相近,分离极具挑战.目前,基于5A分子筛的吸附分离技术在工业上得到了广泛应用,但5A分子筛的吸附容量较低,且无法实现单支链异构体与双支链异构体的选择性分离,限制了汽油辛烷值的进一步提高.金属-有机框架材料等新型多孔材料的结构多样性和高度可设计性使其可以精准识别异构体分子在形状和性质上的微小差异,展现出良好的分离性能和应用前景.重点综述了金属-有机框架材料在己烷异构体分离中的研究进展,归纳了分离机理和影响因素,并对该领域中存在的问题和未来发展方向进行了探讨.

Abstract Various toxic metal ions were successfully removed from solid matrix into supercritical CO2 (scCO2) by open-chain crown ether bridged diphosphates at 313.15 K and 20 MPa, these diphosphates with different ester side chains and different length of ethylene oxide bridge group are highly soluble in supercritical CO2. The extraction efficiency (E%) of heavy metals is between 55 and 89%. Mulliken charge distribution of ligand’s P=O coordination group was calculated to indicate the stability of metal complex. The ligand structure effects and the rationale for different selectivity were discussed. In addition, binding property of these diphosphates towards the alkaline earth metals was further studied following the same extraction procedures. Alkaline earth metal ions Ca2+, Sr2+ and Ba2+ were extracted with E% at 49–74%, 50–73% and 16–64%, respectively. DFT calculations were performed to investigate the interaction energy of the complexes and the correlation with the E% was discussed.

生物质气化过程中副产的焦油不仅有腐蚀设备、堵塞管道等危害,而且会降低生物质气化效率,传统的物理处理与热裂解处理方法存在诸多不足.本文基于旋转弧热等离子体反应装置,以二氧化碳作为等离子介质,选取苯及苯萘混合物作为生物质焦油的模型化合物进行了气化实验,实现了向合成气的高效转化(碳收率可达到90％以上),初步显示了该路线的可行性.进一步分析了真实生物质焦油的物质组成,考察了二氧化碳等离子体对焦油的气化性能,焦油内的水分可作为气化剂,调节合成气中H2/CO的比例(0.3～1).上述结果为生物质焦油无害化、资源化利用技术的发展提供了新的思路.

Gas-liquid chromatography is an effective method to determine infinite dilution activity coefficients (γ∞). Wall-coated open-tubular (WCOT) column which offers more advantages over packed column should be a preferable column type; however, the small carrier gas flow rate and stationary phase amount in WCOT columns limit its application in the determination of γ∞. Mathematical strategy made some progress to avoid the quantification problem in the determination of γ∞ by static-wall-coated open-tubular (SWCOT) columns. However, the previously reported strategy was based on the assumption that SWCOT column was geometrically an ideal hollow cylinder, which indeed deviates from the reality. In this study, without that assumption, we derived a new microgeometry-independent equation by using the relationship between the hold-up volume (VM) and the volume of stationary phase (VL), and used it to measure the γ∞ of various organic solutes in two ionic liquids (ILs) 1‑butyl‑3-methylimidazolium dicyanamide and 1,3-dibutyronitrile-imidazolium bis((trifluoromethyl)sulfonyl)imide, both of which contain double cyano groups in the anion or cation. Phase loading study was adopted to eliminate the influence of interfacial adsorption to partition. The infinite dilution partial molar excess enthalpy, selectivity and capacity were directly calculated from the experimental γ∞ values, and the linear solvation energy relationship (LSER) model was used to characterize the specific properties of both ILs. This new established equation will promote the application of SWCOT columns in thermodynamic measurement and benefit the fast screening of novel solvents for chemical separation processes.

The pore size of adsorbents plays a vital role in determining the overall separation performance of gas separation and purification by adsorption. In this work, the pore apertures of the coordination pillared layer (CPL) was systematically controlled by adjusting the length of pillared ligands. We used pyrazine, 4,4'-bipyridine, and 1,2-di(4-pyridyl)-ethylene with increased length to synthesize CPL-1 (L = pyrazine), CPL-2 (L = 4,4'-bipyridine), and CPL-5 [L= 1,2-di(4-pyridyl)-ethylene], respectively. The aperture size of these CPLs varies from 4 to 11 angstrom: CPL-1 (4 x 6 angstrom(2)), CPL-2 (9 x 6 angstrom(2) ), and CPL-5 (11 x 6 angstrom(2)). Among the three frameworks, CPL-2 exhibits the highest C2H2 uptake at ambient conditions as it has moderate pore size and porosity. However, CPL-1 has the best separation performance in the breakthrough experiments with binary gas mixture of C2H2/C2H4, thanks to the optimal pore size nearly excluding C2H4, which is only observed in the state-of-the-art UTSA-300a so far. The DFT calculations were carried out to elucidate the specific adsorption sites for both acetylene and ethylene among these frameworks. The modeling results suggest that binding strength is highly related to aperture size and that CPL-1 shows the highest adsorption selectivity owing to the optimal pore size. This work demonstrates that engineering pore size enables us to fabricate the highly efficient metal-organic framework (MOF)-based adsorbents for specific gas separation on the basis of the isoreticular chemistry.

Textile dyeing sludge is complex hazardous material with increasing amount year by year, and the conventional treatment techniques are limited by many drawbacks such as water/soil contamination, incomplete degradation of hazardous organics or inefficient fixation of toxic heavy metals. This work reported the first example of thermal plasma gasification treatment of textile dyeing sludge in a homemade rotating arc plasma reactor, which not only significantly reduced the volume and eliminated the safety risk of textile dyeing sludge, but also produced valuable syngas that can be used for chemical industry. At a feed rate of 36 g/min and a CO2 flow rate of 0.43 Nm(3)/h (14.08 g/min), the carbon conversion efficiency of gasification was 99.9%; and the energy conversion efficiency could reach 71.8%; and the lower heating value of syngas-rich produced gas was 8.91 MJ/Nm(3). At the same time, the volume reduction ratio of sludge was 41.19% and the fixing efficiency of the heavy metals in solid products reached above 99%. Toxicity characteristic leaching procedure confirmed the solid products were harmless in a wide environmental pH range. The proposed method exhibits its great potential of simultaneously realizing harmless, minimization and reclamation of textile dyeing sludge and even other hazardous solid waste. (C) 2019 Published by Elsevier Ltd.

A series of highly CO2-soluble open-chain crown ether bridged diphosphates were designed and prepared as chelating ligands which were used to extract lanthanide ions from cellulose paper into supercritical CO2 (ScCO2). These ligands were designed by introducing different ester side chains and joining the two phosphorus groups with different length of ethylene oxide group which could provide enhanced solubility and complexation ability. The solubility data of these synthesized diphosophates in ScCO2 were measured at 313.15 K and 10.65 MPa-13.69 MPa. Lanthanides metal ions including La3+, Ce3+, Pr3+, Nd3+, Sm3+, Gd3+, Er3+, and Yb3+ were successfully removed from the solid matrix by supercritical fluid extractions using these chelating ligands at 313.15 K and 20 MPa. The extraction efficiency of metal ion was affected by chelating ligands' side chain, which increased from 68% to 94% mainly driven by the increased solubility capability.

A visible-light induced direct amidation of benzoylformic acids with tertiary amines has been explored. Tertiary amines underwent N-dealkylative amidation with alpha-keto acid in the presence of [Ir{dFCF(3)ppy)(2)(bpy)]PF6 and Cs2CO3, affording the corresponding alpha-ketoamides in good yields under mild conditions. This transformation exhibits a wide substrate scope and provides a facile synthetic approach to alpha-ketoamides. (C) 2019 Published by Elsevier Ltd.

Ionic liquid (IL)‐stabilized metal nanoparticles (NPs) have attracted increased attention as novel catalysts for various reactions due to their excellent stability and high activity. However, the high viscosity of ILs limits their applications. Here, for the first time, we reported an NPs@IL‐cosolvent liquid–liquid biphasic system for metal NPs catalysis. The NPs were successfully confined to IL phase, and abundant IL droplets containing NPs were generated under the reactant flow. The NPs@IL droplets served as microreactors for the catalysis; while the low viscosity organic phase enabled the rapid mass transfer of substances. The biphasic system exhibited improved performance for acetylene hydrochlorination than that of the pure IL system. An acetylene conversion of 98% and a selectivity of 99.5% were achieved along with a 90% decrease on IL usage. The tolerable gas hourly space velocity in the biphasic system for a satisfactory conversion was almost double that of the pure IL system. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2536–2544, 2018

Polyethylene terephthalate (PET) is one of the most widely used macromolecule materials, but the treatment of waste PET has been a great challenge to environment safety. In this article, we report for the first time an effective method to produce gaseous products containing acetylene, ethylene and carbon monoxide from PET particles using a rotating direct current arc plasma reactor. Thermodynamic simulation was performed, and the effect of input power, PET feed rate and working gas flow rate on PET pyrolysis was experimentally investigated. An almost complete carbon conversion could be achieved by this method with a product gas containing 42% acetylene, 53% carbon monoxide and 4% ethylene, while the specific energy consumption of product gas was below 20 kWh/kg. These results show that rotating arc plasma is a promising method of improving the conversion of waste PET to valuable hydrocarbons and syngas.

The demand for CO2/C2H2 separation, especially the removal of CO2 impurity, continues to grow because of the high-purity C2H2 required for various industrial applications. The adsorption separation of C2H2 and CO2 via porous materials is gaining a considerable attention as it is more energy-efficient compared with cryogenic distillation. The ideal porous materials are those that preferentially adsorb CO2 over C2H2; however, very few adsorbents meet such requirement. Herein, two isostructural cyclodextrin-based CD-MOFs (CD-MOF-1 and CD-MOF-2) were demonstrated to have an inverse ability to selectively capture CO2 from C2H2 by single-component adsorption isotherms and dynamic breakthrough experiments. These two MOFs showed excellent adsorption capacity and benchmark selectivity (118.7) for CO2/C2H2 mixture at room temperature, enabling the pure C2H2 to be obtained in only one step. This work revealed that these materials were promising adsorbents for obtaining high-purity C2H2 via selectively capturing CO2 from C2H2.