Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202507081
Coal chemical waste salt, a solid residue from evaporative crystallization of high-salinity wastewater, poses significant environmental risks and challenges for resource utilization due to its complex composition. This study systematically analyzes its composition and environmental hazards, highlighting its typical "mixed salt" nature and the potential threats of organic pollutants and heavy metals to soil, water, and ecosystems. It reviews mainstream treatment pathways, including organic degradation, inorganic impurity removal, and salt separation, with a focus on the resource utilization of sodium chloride and sodium sulfate and their industrial prospects. The current pollution control technical specifications and product quality standards are examined, comparing the scope and technical points of relevant standards such as the "Technical Specification for Pollution Control of Chemical Waste Salt." Finally, countermeasures are proposed to address challenges including difficult treatment of mixed salts, insufficient resource utilization incentives, and incomplete standard systems, emphasizing technological innovation, policy guidance, and standard improvement.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202508021
Coal chemical industry waste salt, generated from high-salinity wastewater treatment, poses a bottleneck for green transformation under the 'dual carbon' strategy due to its low value and high complexity. This study investigated a typical coal chemical industrial park in Northwest China, using principal component analysis (PCA) on actual waste salt samples to identify pollutant characteristics and assess resource utilization potential. Results showed total organic carbon (TOC) ranged from 707.9 to 7,737.9 mg·kg⁻¹, with benzo(a)pyrene concentrations frequently exceeding the limits of the 'Identification Standards for Hazardous Wastes' (GB 5085.3). Hardness ions and metal ions also surpassed relevant product standards. PCA classified the waste salts into three types: sodium sulfate type, sodium chloride type, and high-complexity mixed salt, each corresponding to distinct resource utilization pathways. The study proposes differentiated technical routes based on PCA classification, providing a feasible reference for classified management and technology selection. This research supports the national policy of 'harmless pretreatment + resource utilization' for waste salt, contributing to green and high-quality development of the coal chemical industry.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3897-6
Decoding the nature of catalytically active sites is an essential prerequisite for the rational design of catalysts for electrochemical H2O2 synthesis, but faces significant challenges, particularly for controversial cobalt single-atom catalysts (Co SACs). Herein, we report trace Co single-atom sites embedded within pyridinic N-rich carbon nanospheres (Co1-NNH3-C), synthesized via a self-assembly coupled surface-coating strategy. The Co1-NNH3-C catalyst demonstrates remarkable H2O2 selectivity (99%) and activity at current density of −3.5 mA cm−2 in 0.1 M H2SO4. Through a combined approach of molecular probe experiments, surface modification, and density functional theory (DFT) calculations, we disclose that pyridinic N, rather than Co single atoms, serves as the direct active site for 2e− oxygen reduction reaction (ORR). The trace Co (0.05 wt%) indirectly facilitated pyridinic N formation during pyrolysis but exhibits negligible direct catalytic involvement. DFT reveals pyridinic N sites optimize OOH intermediate adsorption (ΔG*OOH = 4.0 eV) and minimize reaction overpotential of 0.20 V, enabling scalable H2O2 production (907.5 mmol gcat−1 h−1). This work redefines the role of trace metal in SACs, providing a paradigm for designing metal-induced carbon catalysts for sustainable electrosynthesis for H2O2.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3834-x
Lithium metal anodes face critical barriers to practical application due to dendritic growth and interfacial instability, which cause short cycle life and safety hazards. This work introduces a highly stable and ultrahigh-rate lithium metal anode using a lithiophilic Sm2S3-modified carbonaceous host. The in situ formation of a Li2S-reinforced interphase layer enables highly reversible lithium plating/stripping and uniform deposition. The modified anode achieves an ultrahigh rate capability of 20 mA cm−2 and ultralong cycling stability of 7440 cycles with dendrite-free morphology. In a 4.5 V anode-less Li||LiCoO2 cell with an areal capacity of ~1.93 mA h cm−2, the system sustains over 1100 cycles with 87.2% capacity retention under harsh conditions: an ultralow negative-to-positive capacity ratio (N/P) of ~0.26 and lean electrolyte of ~5 g Ah−1. Furthermore, an anode-less pouch cell with an ultrahigh areal capacity of ~6.01 mA h cm−2 delivers superior cycling performance even at an ultra-low N/P ratio of ~0.71 and ultra-lean electrolyte of ~1 g Ah−1, achieving a high energy density of 505 Wh kg−1. This work provides a scalable and effective strategy for advancing reliable, practical lithium metal batteries.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025021805
This study analyzed 75 precipitation samples collected from August 2017 to August 2018 in the Meili Snow Mountain region of the Hengduan Mountains. The chemical characteristics of inorganic ions and their seasonal variations between monsoon and non-monsoon periods were examined. The volume-weighted mean total ion concentration was 246.2 μeq·L–1, with higher concentrations in the non-monsoon season and lower in the monsoon season. The dominant water chemistry type was HCO3–-Ca2+. Principal component and partial correlation analyses indicated that Ca2+, Mg2+, HCO3–, and SO42– mainly originated from local sedimentary rock dust, while Na+ and Cl– were primarily marine during the monsoon, with reduced marine influence in the non-monsoon period. NO3– was largely attributed to South Asian pollution emissions, with significant contributions from biomass burning to K+, Na+, and Cl– in the pre-monsoon phase. PMF source apportionment confirmed that during the monsoon, approximately 70% of Cl– and Na+ were from sea salt, whereas in the non-monsoon, over half came from biomass burning. NO3– was almost entirely from fossil fuel combustion during the monsoon (96%), decreasing to 72% in the non-monsoon. Ca2+ and Mg2+ were mainly from carbonate dust in the monsoon and weathered dust in the non-monsoon. Backward trajectory analysis showed that the non-monsoon period was dominated by westerly transport (60%), while the monsoon was dominated by southwest monsoon transport (81%). These findings provide scientific basis for understanding atmospheric pollution and background values in the region.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3774-3
Lithium-air capacitor batteries (LACBs) integrate the rapid charge-discharge capability of supercapacitors into conventional lithium-oxygen batteries, significantly enhancing power density. However, their cycling stability remains unsatisfactory. In this study, we incorporated redox mediators (RMs) into an LACB featuring a dual-cathode configuration. This design facilitates sustained electron transfer between the electrode and Li2O2/Oxygen, thereby delaying RM deactivation caused by electrode passivation and improving overall electrochemical performance. The RM-enhanced battery achieved over 250 cycles at 2 mA cm−2 with a limited capacity of 0.5 mAh cm−2, while exhibiting a 0.54 V reduction in charging voltage at 0.1 mA cm−2 compared to the RM-free system. Furthermore, application of an aluminum foil sealing technique enabled a power density of 13.8 mW cm−2 at 6 mA cm−2, overcoming mass transport limitations inherent in open-cell configurations. We also investigated the influence of oxygen barrier films with varying barrier capabilities on LACB performance. Results indicate that films with superior oxygen resistance better maintain a clean capacitor electrode surface, thereby providing more stable electron supply to the RMs and enhancing rate capability and cycling performance. These findings underscore the potential of redox mediators in improving the performance and longevity of LACBs, offering a promising strategy for their future development.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202607009
Resource utilization of food waste is a key measure for implementing waste classification and constructing zero-waste cities in China. However, the technical route based on anaerobic digestion currently faces developmental bottlenecks. In this study, engineering-scale facilities located in Northeast, North, Northwest, and Southeast China were selected, and material flow analysis was employed to comprehensively assess the current status of anaerobic digestion of food waste. The results indicated that, during the pretreatment stage, both leachate and organic slurry from all surveyed regions exhibited high COD/TN ratios, and the leachate contained high concentrations of lipids. Following three-phase (oil-water-solid) separation, the oil recovery rate could reach over 98%. Anaerobic digestion of each ton of food waste from the four regions generated approximately 70 to 80 Nm³ of biogas, while simultaneously producing liquid digestate accounting for 69% to 80% of the total mass and solid digestate accounting for 2.7% to 3.6%. However, the annual continuous production of digestate was not aligned with the seasonal demand for land use, thereby restricting the pathway for resource utilization. Converting food waste into an external carbon source can significantly enhance its resource utilization efficiency, with the economic benefits increasing by more than 203% compared to the methanogenesis pathway. The selection of the carbon source production technology route should be comprehensively determined by taking into account factors such as the specific nitrogen removal requirements of the target wastewater treatment process, the quality requirements for the carbon source products, and the substitution rate of commercial carbon sources.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4079-4
Utilization of ultrahigh-nickel LiNi_xCo_yMn_1-x-yO_2 (NCM) (x > 0.97) in Li-ion batteries can distinctively boost energy density through enhanced discharge capacity. However, capacity and thermal stability deteriorate as Ni content approaches the limit. Here, we propose a facile strategy by introducing high-valence tungsten (W) into ultrahigh-nickel polycrystalline LiNi_0.98Co_0.01Mn_0.01O_2 (PCNCM98). W-doped PCNCM98 (W-PCNCM98) exhibits refined, compactly stacked primary particles, whereas PCNCM98 shows equiaxial, non-uniform larger particles. The refined microstructure enhances mechanical strength: average particle hardness of W-PCNCM98 is 104 MPa, 1.5 times higher than PCNCM98 (68 MPa). This improved mechanical property suppresses lattice volume changes and relieves microcrack formation from H2–H3 phase transition. Consequently, cycling performance in pouch-type full cells is significantly enhanced, with capacity retention of 73% after 2000 cycles at 1 C and 25 °C, 54% higher than PCNCM98. Enhanced structural stability and strong electron affinity of W6+ also improve thermal stability: exothermic peak for W-PCNCM98 is postponed to 203 °C with heat generation of 1287 J g−1, versus 190 °C and 1528 J g−1 for PCNCM98. This high-valent doping strategy stabilizes ultrahigh-nickel NCM cathodes, accelerating large-scale EV applications.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.1016/S1872-5813(26)60762-1
The CO2 dry reforming of methane (DRM) is pivotal for CO2 utilization within the dual-carbon framework, offering advantages in carbon reduction and value-added chemical production. However, shaped catalysts suitable for industrial-scale DRM remain limited. This work constructs a monolithic catalyst using honeycomb cordierite as the structural support, systematically investigating the effects of organic and inorganic binders on coating structure and catalytic performance. Comparative studies reveal that the active coating fabricated with inorganic aluminum sol exhibits a continuous uniform morphology and excellent adhesion strength. During high-temperature calcination, elemental diffusion within Al2O3 networks bridges the cordierite surface with active catalyst particles, forming a (Ni-Mg)AlxO4 composite structure. This creates robust metal-support interactions between active sites and the residual alumina matrix. The interconnected mesoporous framework provides superior pore confinement, contributing to strong coating adhesion, enhanced activity, and improved resistance to carbon deposition in the monolithic m-NCM-Al-sol catalyst. In contrast, coatings derived from inorganic silica sol suffer from detachment and activity loss due to heterogeneous surface structures and poor adhesion. Organic binders demonstrate inferior performance in macroscopic coating uniformity, adhesion strength, mesoporous confinement, and localized electronic effects, resulting in the poorest catalytic performance. By optimizing aluminum sol coating parameters—binder content, active component dosage, and coating cycles—a synergistic balance between coating thickness and mass transfer is achieved. The optimized catalyst demonstrates excellent DRM performance, providing insights for constructing high-performance shaped catalysts with cordierite coatings.
SCIENCE CHINA Materials•2025•DOI: 10.1007/s40843-025-3510-0
The activity and stability of single-atom catalysts (SACs) are intimately associated with the structure of supports. Herein, by employing a van der Waals (vdW) heterostructure support, we construct a highly active and durable Pt SAC for hydrogen evolution reaction (HER). The unique support consists of monolayer MoS2 attaching on hierarchical N-doped carbon nanocages (hNCNC), on which Pt presents as individual single atoms on the hNCNC and as island-like single-atom layers on the MoS2. The optimized Pt1-MoS2/hNCNC demonstrates low overpotential (11 mV at 10 mA cm−2) and high mass activity (5.6 A mgPt−1 at −20 mV) in 0.5 M H2SO4 solution, outperforming commercial Pt/C. Impressively, the Pt1-MoS2/hNCNC exhibits improved long-term stability in proton exchange membrane water electrolyzer relative to commercial Pt/C. The excellent HER performance is attributed to the regulated electronic structure, robust interaction of Pt atoms with MoS2/hNCNC and facilitated charge transfer. This study establishes an innovative strategy to develop a highly active and durable Pt SAC using vdW heterostructure supports.