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With the rapid growth in the number of passenger cars (PCs) in China over the past decades, more than ten million tons of used tires have already become solid wastes and subsequently caused serious environmental issues. Due to the presence of synthetic rubber in PC tires, waste PC tires cannot be disposed through rubber reclaiming technology. Thus, waste PC tires have become one of fastest growing solid wastes in China. First, the current disposal capacity of the pyrolysis method, regarded as a promising technology for the disposal of waste PC tires, is surveyed and compared with other disposal methods mentioned in previous papers. Second, this work establishes a model to predict the total number of waste PC tires in the next five years depending on the rate of PC growth and current waste tire disposal capacity. Moreover, pyrolysis is evaluated on 15 collected waste PC tires selected from the most representative tire brands in the Chinese market. The corresponding results imply that ∼68.5% of S was into oil and ∼44.3% N and large amount of heavy metals resided in solid carbon which severely limit further applications. Finally, a new pyrolysis technology is introduced that may represent a solution to the limits in the application of tire disposal methods and relief for the coming waste tire crisis.

Cu-ZSM-5-IE+CP exhibited excellent catalytic performance as a result of the synergistic effect between CuO and Cu2+ species.

Cu-ZSM-5 was selected as a candidate catalyst to explore the interaction between coal gas components and elucidate the reaction mechanism in the coal-gas-SCR process.

N2O is a greenhouse gas and a candidate oxidant. Volatile organic pollutants (VOCs) have caused great harm to the atmospheric ecological environment. Developing the technique utilizing N2O as the oxidant to oxidize VOCs to realize the collaborative purification has significant importance and practical value for N2O emission control and VOC abatement. Therefore, the study of N2O catalytic oxidation of tert-butanol based on zeolite catalysts was carried out. A series of molecular sieves, including FER, MOR, ZSM-5, Y, and BEA, were selected as the catalyst objects, and the 1.5% wt Fe and Co were, respectively, loaded on the zeolite catalysts via the impregnation method. It was found that the catalytic performance of BEA was the best among the molecular sieves. Comparing the catalytic performance of Fe-BEA under different load gradients (0.25~2%), it was found that 1.5% Fe-BEA possessed the best catalytic activity. A series of characterization methods showed that Fe3+ content in 1.5% Fe-BEA was the highest, and more active sites formed to promote the catalytic reaction. The α-O in the reaction eventually oxidized tert-butanol to CO2 over the active site. The Co mainly existed in the form of Co2+ cations over Co-BEA samples; the 2% Co-BEA possessing higher amounts of Co2+ exhibited the highest activity among the prepared Co-BEA samples.

The crystal plane effects played pivotal roles in the design of catalysts. In this paper, the branched Ni (Ni-BN) catalyst mainly exposed of Ni(322) surface was synthesized in the presence...

Direct oxidation of methane to methanol (DMTM) constitutes a big challenge in C 1 chemistry. Herein, we present a continuous N 2 O-DMTM investigation by simultaneously introducing 10 vol% H 2 O into the reaction system over Cu-BEA zeolites. Combining a D 2 O isotopic tracer technique and ab initio molecular dynamics (AIMD) simulation, we for the first time demonstrate that the H 2 O molecules can participate in the reaction through a proton transfer route, wherein the H 2 O molecules can build a high-speed proton transfer bridge between the generated moieties of CH 3 - and OH - over the evolved mono(μ-oxo) dicopper ([Cu-O-Cu] 2+ ) active site, thereby pronouncedly boosting the CH 3 OH selectivity (3.1 → 71.6%), productivity (16.8 → 242.9 μmol g cat -1 h -1 ) and long-term reaction stability (10 → 70 h) relative to the scenario of absence of H 2 O. Unravelling the proton transfer of H 2 O over the dicopper [Cu-O-Cu] 2+ site would substantially contribute to highly efficient catalyst designs for the continuous DMTM.

The chlorine (Cl2) drying technology using ionic liquids (ILs) as absorbents was proposed for the first time and systematically investigated from the molecular level scaled up to the industrial level. The hygroscopic IL [EMIM][CH3SO3] was screened as a suitable absorbent from 238 potential IL candidates consisting of 14 cations and 17 anions, by calculating the Cl2 and H2O solubility and separation selectivity of Cl2 to H2O in different ILs based on the COSMO-RS model. The microscopic atomic and molecular insights into the separation mechanisms were deeply revealed by using COSMO-RS model analyses (i.e., σ-profiles, σ-potentials, excess enthalpies, entropies, and Gibbs free energies) and quantum chemistry calculation (binding energies and weak interaction analyses). The Cl2 solubility in pure IL and H2O + IL systems were predicted by the COSMO-RS model, and the results agree with the microscopic mechanism identification. Moreover, the strict equilibrium stage model employed with the COSMO-RS model parameters was built to perform the process simulation, and continuous Cl2 drying with ILs was conceptually designed and optimized at industrial scale. It was confirmed that [EMIM][CH3SO3] is a very promising absorbent leading to a less IL amount, a much lower energy consumption than the other IL [EMIM][BF4], which has a very bright industrialization potential used for Cl2 drying technology.

In this work, a mixed absorbent of an ionic liquid (IL) and triethylene glycol (TEG) is first proposed for natural gas (NG) dehydration. The hydrophilic [EMIM][BF4] is selected as an appropriate IL...

1,2-Butene carbonate (BC) is an important five-membered cyclic carbonate with a high commercial value, but its massive production is limited by the lack of raw material 1,2-butanediol (1,2-BDO). 1,...

1-Ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([EMIM][Tf2N]) ionic liquid as a novel absorbent has excellent performance in BTX absorption. However, compared with the traditional ...

Aromatic hydrocarbons are considered a class of extremely hazardous atmospheric pollutants of volatile organic compounds (VOCs). Toluene is a typical aromatic VOC representative, and its removal ha...

SSZ-13, a CHA-type aluminosilicate zeolite, has attracted substantial attention recently due to its extraordinary physicochemical properties, and Cu-modified SSZ-13 has been commercialized as a sel...

Present work systematically investigates the kinetic role played by H2 molecules during Ni surface diffusion and deposition to generate branched Ni nanostructures by employing Density Functional Theory (DFT) calculations and ab initio molecule dynamic (AIMD) simulations, respectively. The Ni surface diffusion results unravel that in comparison to the scenarios of Ni(110) and Ni(100), both the subsurface and surface H hinder the Ni surface diffusion over Ni(111) especially under the surface H coverage of 1.5 ML displaying the lowest Ds values, which greatly favors the trapping of the adatom Ni and subsequent overgrowth along the 〈111〉 direction. The Ni deposition simulations by AIMD further suggest that both the H2 molecule (in solution) and surface dissociatively adsorbed atomic H can promote Ni depositions onto Ni(111) and Ni(110) facets in a liquid solution. Moreover, a cooperation effect between H2 molecules and surface atomic H can be clearly observed, which greatly favors Ni depositions. Additionally, in addition to working as the solvent, the liquid C2H5OH can also interact with the Ni(111) surface to produce the surface atomic H, which then favored the Ni deposition. Finally, the Ni deposition rate predicted using the deposition constant (Ddep) was found to be much higher than its surface diffusion rate predicted using Ds for Ni(111) and Ni(110), which quantitatively verified the overgrowth along the 〈111〉 and 〈110〉 directions to produce the branched Ni nanostructures.

The pyrolysis of passenger-car-waste-tires (PCWT) has recently attracted widespread attention because it is a highly effective disposal method. However, a comprehensive understanding of real tire pyrolytic processes is limited owing to the complicated PCWT pyrolysis reaction system, particularly regarding the reaction mechanism. This study investigated the PCWT pyrolytic processes using a thermogravimetric analyzer coupled with mass spectrometry and analyzed all the pyrolytic products using pyrolysis-gas chromatography coupled with mass spectrometry. The composition and distribution of the PCWT pyrolytic products were investigated under a kinetic regime to eliminate other influences on the intrinsic reaction. The pyrolytic products mainly consisted of chain and cyclic alkenes, and monocylic aromatics. Importantly, an integral pyrolytic mechanism network for the PCWT was established based on the pyrolysis of single rubbers (natural, styrene butadiene, and butadiene rubbers). The reaction routes for the main products were determined according to the mechanism. Moreover, a kinetic study of the PCWT pyrolysis revealed the activation energy for this complicated reaction system.

MFI zeolite characterized by uniform pore size, adjustable acidity, and high-temperature resistance has a broad application prospect in catalytic reactions. However, controlling the product distribution of zeolite as a catalyst is still confronting great challenges and applications. It is considered as an effective way to control the product distribution by developing and improving new zeolites to modulate their shape selective effect. In recent years, researchers have achieved remarkable successes in investigating the shape selective modulation of zeolites on catalytic reaction and molecular diffusion. The microporous channels of MFI zeolite are the main places for the entry and exit of reactants or product molecules. This review provides the research progress of the shape-selective modulation of MFI zeolite channels and its influence on a series of catalytic performances in recent years. The shape-selective modulation of microporous channels of zeolite, encapsulation of micropores to metals, catalysis of mesoporous zeolite, and the distribution of framework Al were all systematically discussed. The development of advanced catalysts still faces great challenges and potential applications. Finally, we discussed the problems to be addressed urgently in the field of zeolite catalysts in the future.

Direct oxidation of methane to methanol (DMTM), constituting a major challenge for C1 chemistry, has aroused significant interest. The present work reports the synergistic effect of neighboring [Fe]--[Cu] cations, which can significantly boost the CH3OH productivity (100.9 and 41.9 → 259.1 μmol∙g−1cat∙h−1) and selectivity (0.28 and 17.6% → 71.7%) of the best performing Fe0.6%Cu0.68%-BEA (relative to monomeric Fe1.28%- and Cu1.28%-BEA) during the continuous H2O-mediated N2O DMTM. The combined experimental (in situ FTIR, D2O isotopic tracer technique) and theoretical (DFT, ab initio molecular dynamics (AIMD)) studies reveal deeper mechanistic insights that the synergistic effect of [Fe]--[Cu] can not only significantly favor active O production (ΔG = 0.18 eV), but also efficiently motivate the reaction following a H2O proton-transfer route (ΔG = 0.07 eV), eventually strikingly promoting CH3OH productivity/selectivity. Generally, the proposed strategy by employing the synergistic effect of bimetallic cations to modify DMTM activity would substantially favor other highly efficient catalyst designs.

Chlorinated volatile organic compounds (VOCs), of which dichloromethane (DCM) has become one of the main components because of its extensive use and strong volatility, are recognized as extremely hazardous and refractory pollutants in the atmosphere. The efficient treatment of DCM is of great significance to the protection of environment and human health. In this work, the strategy of DCM capture with deep eutectic solvents (DESs) with different hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs) was proposed and systematically investigated. The experimental results show that tetrabutylphosphonium chloride: levulinic acid ([P

Small gas molecule such as H2 has been widely reported to be used as the structure-directing agent that assists synthetic processes of diverse structured metal nanocrystals. Herein, we systematical...

The life cycle environmental sustainability of the natural gas (NG) dehydration process using novel dehydrant [EMIM][Tf2N] ionic liquid (IL) has been evaluated using a “cradle to grave” life cycle ...

This work proposed to use the ionic liquid [EMIM][BF4] as absorbent for the absorption of gaseous acetic acid. The feasibility of this technology was investigated from molecular level to industrial scale. The acetic acid absorption experiment was carried out using [EMIM][BF4], and the removal ratio of acetic acid in the gas product can achieve 88.6% at 20 °C under atmospheric pressure at the laboratory scale. Based on the experimental results, a reliable strict equilibrium phase model embedding the parameters of the UNIFAC model was established. On this basis, the conceptual process design and optimization of acetic acid removal by [EMIM][BF4] at an industrial scale was done, and the most suitable design and operation parameters were obtained. For a further step, the binding energy between [EMIM][BF4] and acetic acid was calculated to give some insights into the separation mechanism, and the results indicate that the interaction between acetic acid and IL is much stronger than that between nitrogen and IL. Moreover, hydrogen bond can be formed between the cation-acetic acid as well as the anion-acetic acid. Keywords: Ionic liquid (IL), Gaseous acetic acid, Absorption, Process simulation, Separation mechanism

A series of Pd-La/SiO2/cordierite (cordierite = COR) and Pd-Zn/SiO2/COR bimetallic monolithic catalysts were prepared, characterized, and tested for the hydrogenation of 2-ethylanthraquinone (eAQ) as the key step of anthraquinone method for production of H2O2. It was found that the metal particle size is remarkably dependent on the Pd/M (M = La, and Zn) mass ratio of bimetallic monolithic catalysts. By virtue of its small metal particle size and the strong interaction, the 0.8% Pd-0.4% La/SiO2/COR monolithic catalyst presents the highest H2O2 yield (7.7 g L−1) and selectivity toward active quinones (95%), which is attributed to the addition of La leading to the synergistic effect between Pd and La. Moreover, the density functional theory (DFT) calculations for the adsorption of eAQ over the surface of Pd-La/SiO2/COR and Pd-Zn/SiO2/COR bimetallic monolithic catalysts have been conducted to further understand the mechanism of molecule–surface interactions between eAQ and the PdM(1 1 1) or Pd(1 1 1) surfaces. Detailed studies showed that the high catalytic activity of Pd-La/SiO2/COR bimetallic monolithic catalyst is attributed to the stronger adsorption between Pd3La1 (1 1 1) and the carbonyl group of eAQ.

Direct oxidation of methane to methanol (DMTM) is a big challenge in C

Present work systematically investigates the kinetic role played by H2 molecules during Ni surface diffusion and deposition to generate branched Ni nanostructures by employing Density Functional Theory (DFT) calculations and ab initio molecule dynamic (AIMD) simulations, respectively. The Ni surface diffusion results unravel that in comparison to the scenarios of Ni(110) and Ni(100), both the subsurface and surface H hinder the Ni surface diffusion over Ni(111) especially under the surface H coverage of 1.5 ML displaying the lowest Ds values, which greatly favors the trapping of the adatom Ni and subsequent overgrowth along the 111 direction. The Ni deposition simulations by AIMD further suggest that both the H2 molecule (in solution) and surface dissociatively adsorbed atomic H can promote Ni depositions onto Ni(111) and Ni(110) facets in a liquid solution. Moreover, a cooperation effect between H2 molecules and surface atomic H can be clearly observed, which greatly favors Ni depositions. Additionally, in addition to working as the solvent, the liquid C2H5OH can also interact with the Ni(111) surface to produce the surface atomic H, which then favored the Ni deposition. Finally, the Ni deposition rate predicted using the deposition constant (Ddep) was found to be much higher than its surface diffusion rate predicted using Ds for Ni(111) and Ni(110), which quantitatively verified the overgrowth along the 111 and 110 directions to produce the branched Ni nanostructures.

Surface segregation constitutes an efficient approach to enhance the alkaline hydrogen evolution reaction (HER) activity of the bimetallic PtxNiy nanoalloys. Herein, we propose a new strategy by utilizing the small gas molecule of H2 as the structure directing agent (SDA) to in-situ induce Pt surface segregations over a series of PtNi5-n samples with extremely low Pt dopings (Pt/Ni = 0.2). Impressively, the sample of PtNi5-0.3 synthesized under 0.3 MPa H2 delivers an unprecedentedly low overpotential of 12.8 mV (-10 mA cm-2) and Tafel slop of 14.1 mV dec-1, which is superior than most of previously reported PtxNiy electrocatalyst. This is closely related to the strong in-situ inducing effect of H2 (0.3 MPa) leading to an obvious Pt-rich@Ni-rich core-shell nanostructure which can efficiently reduce the reaction Gibbs free energies. Finally, the specific mechanistic effects of H2 during PtNi5-n synthesis process are well illustrated based on the combined experimental and theoretical studies.

In this work, the technology for absorbing methyl tert-butyl ether (MTBE) with ionic liquids (ILs) is first proposed and systematically investigated from the molecular level to system scale. The imidazolium-based ILs, [BzMIM][Tf2N] and [AMIM][Tf2N] are screened from 272 IL species using the COSMO-RS model. The absorption mechanism at the molecular level is explored by combined characterization techniques (i.e. 1H NMR and FT-IR) with quantum chemical (QC) calculations (i.e. binding energy and weak interaction analyses). The vapour-liquid equilibrium (VLE) of MTBE-IL and MTBE-triethylene glycol (TEG) systems are experimentally determined and predicted through the UNIFAC-Lei model. The results show that the model can well quantitatively predict the VLE of these mixed systems. Moreover, the equilibrium absorption capacities of MTBE in ILs and TEG are measured and the magnitude is in the order of [BzMIM][Tf2N] > [AMIM][Tf2N] > TEG. The equilibrium stage and rate-based models on the basis of the UNIFAC-Lei model is established to perform the process design and optimization for MTBE absorption. When achieving the same separation task (i.e., MTBE content in the product gas less than 500 ppm in mole fraction), the mixed absorbent of [AMIM][Tf2N] + TEG has the lower loss of product gas and the lower energy demands (i.e., heating and cooling energy along with exergy demands) compared with the pure TEG and pure IL processes. This validates that ILs are potential absorbents and IL-based mixed absorbents may be the better strategy for achieving highly efficient absorption of MTBE.

Vapor pressure data for the binary systems (water/methanol/ethanol + 1-ethyl-3-methylimidazolium acetate ([EMIM]+[Ac]−)) and the ternary systems (methanol + water + [EMIM]+[Ac]−, ethanol + water + [EMIM]+[Ac]−, and methanol + ethanol + [EMIM]+[Ac]−) were measured by a modified equilibrium still. For the above systems, the maximum average relative deviation between experimental data and the UNIFAC-Lei model predicted values was 7%, confirming the prediction accuracy of the UNIFAC-Lei model. Thus, this model was further used to predict the isobaric vapor–liquid equilibrium (VLE) data at 101.3 kPa for the methanol + water + [EMIM]+[Ac]−, ethanol + water + [EMIM]+[Ac]−, and methanol + ethanol + [EMIM]+[Ac]− systems at a fixed mole fraction of ionic liquid (IL) (xIL = 0.2). It was demonstrated that the ionic liquid [EMIM]+[Ac]− was an appropriate entrainer to separate the methanol–ethanol–water mixture. On this basis, the extractive distillation process was simulated using the rigorous equilibrium (EQ) stage m...