New Carbon Materials•2026•DOI: 10.1016/S1872-5805(25)61036-5
Large graphene oxide (LGO) sheets offer significant advantages over smaller ones in various applications, yet their production via Hummers-type oxidation of large natural graphite flakes remains challenging due to difficulties in achieving full oxidation and avoiding fragmentation. This study provides the first direct evidence that large graphite flakes (up to 1 mm) can be completely oxidized without fragmentation under static conditions, as revealed by in-situ monitoring. The oxidation process is governed by diffusion of the oxidizer between layers, described by Fick's law, where a high oxidizer concentration gradient increases the diffusion rate. By minimizing the amount of concentrated H2SO4 solvent, we achieved a semi-solid state that elevates oxidizer concentration, facilitating Mn(VII) diffusion and enabling complete oxidation of gram-scale large flakes with significantly reduced reagent consumption. Reaction temperature was optimized to balance graphite oxidation and Mn(VII) self-decomposition. Using this approach, 200-, 100-, and 50-mesh natural graphite were fully oxidized with reduced H2SO4 and KMnO4 usage. After exfoliation, LGO with average lateral sizes of 27.3, 58.7, and 116.2 μm were obtained, respectively, with 100% conversion and yield over 165%. This work not only provides a scalable, cost-effective strategy for LGO production but also advances the fundamental understanding of Hummers-type oxidation.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202506064
To address the challenges of high salinity, recalcitrance, limited mass transfer, and coating detachment in traditional anodes for textile wastewater treatment, a porous RuO2@r-TiO2 nanotube array (NTA) anode was fabricated via anodic oxidation, electrochemical reduction, and thermal decomposition. A flow-through electrochemical oxidation system was constructed using this anode and a graphite felt cathode. The material's morphology and physicochemical properties were characterized by SEM, XRD, and XPS. Congo red (CR) was used as a model pollutant to evaluate degradation performance under various conditions. Optimal conditions were identified as current density 5 mA·cm−2, permeate flux 480 L·(m2·h)−1, initial CR concentration 0.15 mmol·L−1, and NaCl concentration 75 mmol·L−1. Under these conditions, the system achieved 91% decolorization within 20 min and 82% mineralization within 60 min. Mass transfer tests showed a rate constant of 2.23×10−4 m·s−1 in flow-through mode, three times higher than conventional mode, with active chlorine and H2O2 production increased by 32.8% and 66.7%, respectively. Radical quenching experiments indicated that singlet oxygen (1O2) was the primary reactive species. The degradation mechanism was proposed based on quenching and UV spectral analysis. The system achieved >90% decolorization for five typical dye pollutants with an energy consumption of only 0.16 kWh·m−3. Cyclic voltammetry confirmed long-term stability. These findings provide theoretical support for applying electrochemical advanced oxidation to high-salinity textile wastewater.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202509053
The escalating global generation of waste plastics necessitates robust recycling strategies to mitigate environmental impact and advance low-carbon development. This study employs life cycle assessment (LCA) and emission factor methodologies to quantify the carbon footprints of six distinct waste plastic valorization pathways: mechanical recycling, pyrolysis, alcoholysis, co-coking, solid fuel production, and direct incineration. The functional unit is one tonne of waste plastic, with system boundaries encompassing transportation, pretreatment, and resource utilization. The model accounts for indirect emissions from energy consumption, direct emissions from plastic decomposition, and carbon offsets from material or energy recovery. Results indicate that pyrolysis yields the highest carbon offset of approximately -3,024 kgCO2e per tonne, while mechanical recycling achieves an 88% material recovery rate and a net carbon offset of -991.4 kgCO2e. Net carbon emissions per tonne of waste plastic rank as follows: direct incineration (1,104 kgCO2e) > co-coking (185.8 kgCO2e) > solid fuel (115.4 kgCO2e) > alcoholysis (-259.5 kgCO2e) > mechanical recycling (-991.4 kgCO2e) > pyrolysis (-2,592 kgCO2e). These findings demonstrate that pyrolysis offers superior carbon reduction benefits compared to incineration, exhibiting a net-negative carbon footprint across its life cycle. The study provides a scientific basis for selecting low-carbon waste plastic valorization routes and informs carbon trading and emission reduction strategies in the solid waste sector.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.1016/S1872-5813(26)60690-1
Methane cracking driven by electric power holds significant promise in the context of the rapid development of renewable energy. The effects of carrier gas ratio, input power, and inlet gas flow rate on CH4 cracking performance were systematically investigated in a dielectric barrier discharge (DBD) reactor. The variation of temperature distribution and reaction energy intensity were also examined. The experimental results indicate that CH4 conversion and gaseous product formation are promoted by increasing the DBD input power or decreasing the inlet gas flow rate. At an input power of 90 W and an inlet gas flow rate of 200 mL/min, the single-pass CH4 conversion reaches 46.6%, with an H2 yield of 23.3%, demonstrating that CH4 cracking is governed by electron induced reactions. While the Joule heating from the inner and outer electrodes is relatively limited. The reaction energy intensity increases as the CH4 conversion decreases. When the inlet gas flow rate increases from 200 to 800 mL/min, the energy intensity rises by approximately 2.8 times, indicating that higher inlet gas flow rates enhance the convective heat transfer and shorten the gas residence time, thereby suppressing deep CH4 cracking. Moreover, BOLSIG+ calculations further reveal that CH4 activation is dominated by electron induced vibrational excitation, in which stepwise energy accumulation drives C–H bond dissociation. The energy transfer and species transformation pathways of overall CH4 cracking process, which comprises electron energy injection, vibrational excitation, stepwise dissociation, radical chain extension, and final product formation, can be summarized into three stages, i.e. methane activation, radical evolution, and product formation.