Xiaochun Chen

Developing efficient and recyclable catalysts is crucial for advancing the chemical recycling of polyethylene terephthalate (PET). In this study, a series of ionic liquids derived from methylpiperidine (MP) with adjustable structures were constructed, and their application in PET glycolysis was evaluated. By adjusting the substitution positions on the MP framework, introducing alkyl chains, and changing the coordinating metal center, the catalytic system was optimized to enhance reaction activity and durability. The optimized catalyst (1‐C ₆ ‐2MP/Zn(OAc) ₃ ) enabled PET to degrade rapidly, achieving a BHET yield of 93.27% within 60 min at 185°C using 4 wt% catalyst. Moreover, this system demonstrated excellent reusability, maintaining a BHET yield above 90% after 10 consecutive cycles. Kinetic analysis indicated that the reaction followed a pseudo‐first‐order model, with an apparent activation energy of 79.59 kJ mol ⁻¹ , suggesting a relatively low energy barrier. The catalyst also showed good applicability in commercial PET glycolysis. Overall, this study revealed clear structure‐performance relationships and provided guidance for the rational design of robust ionic liquid catalysts for sustainable PET recycling.

Triethyl methyl ammonium ionic liquid as an electrolyte additive is designed to inhibit the growth of zinc dendrites and the shuttling effect of I ₃ ⁻ ions for zinc–iodide batteries.

In this work, FeS supported SBA-15 mesoporous silica catalyst (FeS@SBA-15) was synthesized successfully, characterized and first applied to persulfate (PS) activation for the degradation of imidacloprid in wastewater. The as-prepared 3.5-FeS@SBA-15 presented an impressive imidacloprid removal efficiency of 93.1% and reaction stoichiometric efficiency (RSE) of 1.82% after 5 min, ascribed to the synergetic effects of improved FeS dispersion and abundant surface sites by SBA-15. Electron paramagnetic resonance spectra and quenching experiments proved that both SO₄^·- and ·OH were produced in FeS@SBA-15/PS system, and SO₄^·- played a dominant role in the degradation process. The S^2- can accelerate the cycling of Fe(III)/Fe(II) during activation and increase the steady-state concentration of Fe(II). More importantly, the constructed heterogeneous system exhibited an efficient and stable catalytic activity over a wide range of pH (3.0-9.0), temperature (283K-313K), inorganic ion (NO₃^-) and humic acid (1-20 mg/L). Moreover, the density functional theory calculations were conducted to predict the potential reaction sites of imidacloprid. Based on eighteen identified intermediates, four main degradation pathways were proposed: hydroxylation, dechlorination, hydrolysis, and the ring cleavage of the imidazolidine. ECOSAR analysis indicated hydroxylation and dechlorination played a key role in the detoxification of the formed compounds. These findings would provide new insights into the application of FeS@SBA-15 catalyst in wastewater treatment and the removal mechanism of imidacloprid from wastewater.

China is the largest producer and exporter of coke globally, which means that it is very important to understand the characteristics of air pollutants and carbon emissions from China’s independent coking industry. This study was the first to establish a bottom-up inventory of the air pollutants and carbon emissions of China’s independent coking industry during 2001–2018 based on continuous emission monitoring system online monitoring data and unit-based corporate information. Based on the developed emission inventory, four scenarios were established to analyze potential emissions reduction of air pollutants and carbon dioxide (CO₂) in future. The emissions of particulate matter (PM₁₀ and PM_2.5), sulfur dioxide (SO₂), black carbon (BC) and organic carbon (OC) decreased by 62.11%, 63.41%, 72.85%, 63.41% and 63.41%, respectively. CO₂, carbon monoxide (CO), volatile organic compounds (VOCs) and nitrogen oxides (NO_X) emissions increased by 355.51%, 355.51%, 355.51% and 99.74%, respectively. In 2018, PM₁₀, PM_2.5, SO₂, NOx, BC, OC, CO, VOCs and CO₂ emissions were, respectively. 45.20, 16.91, 63.84, 117.71, 5.07, 5.92, 554.91, 1026.58 Gg, and 176.88 Tg. Shanxi province made the greatest contributions to the total emissions of air pollutants and CO₂ from this industry by 25.01%. The emission source that contributed most to PM_2.5 (SO₂ and NO_X) emissions was coke pushing (quenching and the coke oven chimney respectively) in 2018. Under the ULE scenario (2018–2035), PM_2.5 and SO₂ emissions will reduce by more than 30%. Under the PCP scenario, PM_2.5 and SO₂ emissions will reduce by more than 55%. Under the CBP scenario, CO₂ emissions will peak at 197.99 Tg in 2025 and decrease to 70% of the peak in 2035. The results showed the emission characteristics of air pollutants and CO₂, future emission with several scenarios and cooperative reduction potential in China’s independent coking industry, which provides scientific support for the development of pollution control strategies.

Extractive denitrification (EDN) of shale oil using ionic liquids (ILs) as the extracting agent has good industrial prospects. In such processes, ILs with higher selectivity to N-compounds and lower solubility in shale oil are desired to improve the EDN efficiency, and reduce the loss of ILs and the contamination of shale oil. In the present study, we employed COSMO-RS to calculate the selectivity of 70 ILs to the typical N-compounds (pyridine, quinoline and indole). The influence of the IL structural characteristics, composition of shale oil and properties of N-compounds are investigated from a micro-level view with the σ-surface and σ-profile. The selectivity strongly depends on anionic species and it is greatly influenced by hydrogen bonding (HB) and π–π interaction between N-compounds and ILs. ILs composed of [H₂PO₄]⁻ and [MeSO₃]⁻ with larger HB donor energy show higher selectivity to the basic N-compounds, while ILs composed of [Ac]⁻ with larger π-electron cloud density show higher selectivity to the non-basic N-compounds. Anions with stronger polarity have lower solubility in shale oil. Moreover, experimental determinations of EDN indicated that [C₄py][H₂PO₄]/[C₄mim][H₂PO₄] and [C₂mim][Ac]/[C₂py][Ac] have good EDN performance for quinoline/pyridine with efficiency of 100% and for indole with efficiency of 91%, respectively. This work presents a theoretical basis to design and select ILs having higher selectivity for N-compounds and lower solubility in shale oil for use in denitrification.

Ethyl acetate is one of typical volatile organic compounds (VOCs) emitting from solvent use, and removing ethyl acetate from exhaust air is vital to VOCs abatement. The mesoporous manganese oxide (MnO_x) samples were sonochemically synthesized by the reduction of KMnO₄ using Mn(NO₃)₂. The characterization shows that γ‐MnO₂, β‐MnO₂, and bixbyite‐like Mn₂O₃ were obtained by calcining the MnO_x samples from 200°C to 500°C. The results show that γ‐MnO₂ and β‐MnO₂ possess more Mn⁴⁺ than bixbyite‐like Mn₂O₃. β‐MnO₂ has the highest contents of surface oxygen species (O_ads) and average oxidation state (AOS) among the MnO_x catalysts. Based on a 7‐day test, β‐MnO₂ performed the highest activity for the catalytic ozonation of ethyl acetate compared with the other MnO_x catalysts. The results show that ethyl acetate is easy to be destroyed but difficult to be completely mineralized by catalytic ozonation. Lower gas hourly space velocity (GHSV) leads to higher CO₂ selectivity and more intermediate products form in the catalytic ozonation of ethyl acetate under higher GHSV. A further study indicates that β‐MnO₂ has a long‐term stability for catalytic ozonation of ethyl acetate because the accumulation and the decomposition of intermediate products are in a dynamic equilibrium during the catalytic ozonation.

1,3-Dimethylimidazolium dimethylphosphate ([C₁mim][DMP]) was observed experimentally to be able to eliminate the atmospheric azeotropic point of acetone and methanol, which is an important azeotrope generally encountered in furfural production and the Fischer-Tropsch process. Here, we employed ab initio calculation to understand the underlying mechanism of [C₁mim][DMP] in eliminating the azeotropic point of acetone and methanol. Structure, energy and interaction in binary-, ternary- and quaternary-clusters composed of methanol, acetone, [C₁mim]⁺ or/and [DMP]‾ were calculated. The σ-hole, AIM and NBO analyses were performed to understand intermolecular interaction with electron density, electron occupancy, charge transfer and molecular orbital interaction. Hydrogen bond interaction plays a key role in azeotropic point elimination; due to the much stronger hydrogen bond interaction between methanol and [C₁mim][DMP] than that between acetone and [C₁mim][DMP], [C₁mim][DMP] prefers to interact with methanol rather than acetone, and the original interaction between methanol and acetone is separated by [C₁mim][DMP]. The hydrogen bond is from the orbital interaction between O lone-pair-electron orbitals of the hydrogen bond acceptor and σ * (C-H) or σ * (O–H) anti-bonding orbitals of the hydrogen bond donor, where remarkable electron or charge transfer occurs. These theoretical calculation results are in agreement with the experimental observation that [C₁mim][DMP] eliminates the azeotropic point of methanol and acetone. This work shows that ab initio calculation may be employed to rationalize the design or synthesis of ionic liquids for separating azeotropes. Elimination of azeotropic point of acetone and methanol by [C₁mim][DMP]

Elimination of nitrogen (N) compounds contained in fuel oils is one of the essential processes for petroleum refinery due of their hindering consequences on the hydrodesulfurization (HDS) process. Traditional hydrodenitrogenation (HDN) techniques have some barriers to produce lower-N or N-free fuel oils, e.g., HDN is less effective to remove some cyclic N-compounds; HDN is expensive because of operating conditions such as high pressure and high temperature, and also requires the presence of an expensive catalyst and hydrogen. Application of ionic liquids (ILs) for the purpose of fuel oil extractive denitrogenation (EDN) has been an important part of research in recent years, and it has shown huge potential as an effective substitute or supplemental technique to HDN. In the present review, we studied research results of EDN using ILs and have discussed widely the diversified factors influencing denitrogenation. This review concludes that EDN employing ILs has a promising future owing to the ideal physical and chemical characteristics of ILs; though for such a new technology there are some challenges, for which a discussion is also given. This review contributes proposals for possible commercial application of ILs in EDN.