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The Silk Road Economic Belt has become a pivotal region for China's sustainable development, focusing on the balance between carbon emissions and ecological resilience. Understanding the coordination between these factors is crucial for advancing China's westward economic shift and optimizing urban and demographic structures. This study investigates the coupling and coordination dynamics between carbon emissions and ecological resilience across 15 key cities in the Silk Road Economic Belt, using data from 2008 to 2018. By applying a ''pressure-state-response'' framework, the ecological resilience of the region is quantitatively assessed. Spatial disparities and the dynamic evolution of coupling coordination are analyzed through the Gini coefficient and kernel density estimation. The findings reveal significant regional variations in ecological resilience and a decline in coupling coordination over time. Shifts in the patterns of coordination indicate opportunities for enhancing resource utilization and environmental management. This research provides theoretical insights for policymakers to improve green development strategies, optimize industrial structures, and plan urban green spaces more effectively within the Silk Road Economic Belt.

China’s rapid urbanization has significantly impacted carbon emissions in rural areas, driving the need for region-specific carbon management strategies to achieve the country’s dual carbon goals. However, previous research has primarily focused on large urban centers, leaving a gap in understanding the spatial and temporal patterns of carbon emissions at the county level in rural regions. This study focuses on the Guanzhong region of Shaanxi Province and develops a county-level carbon emission accounting system based on geographic, socio-economic, and land-use data. The carbon emissions are categorized into energy, industrial processes, agriculture, and waste management. Key findings indicate that industrial and residential sectors are the primary contributors to carbon emissions, with Xi’an being the largest emitter. Carbon emission intensity follows a ranking of Xi’an < Weinan < Baoji < Xianyang < Tongchuan. Spatial patterns show a “core-edge” distribution, with higher emissions in urban centers and lower emissions in rural areas. The study also highlights the carbon sink potential in the southern Qinling National Park. This research provides a valuable framework for rural low-carbon development and offers critical insights for policymakers aiming to balance carbon reduction and economic growth in rural China.

Abstract The potential for toxic elements to contaminate soil has been extensively studied. Therefore, the development of cost-effective methods and materials to prevent toxic element residues in the soil from entering the food chain is of great significance. Industrial and agricultural wastes such as wood vinegar (WV), sodium humate (NaHA) and biochar (BC) were used as raw materials in this study. HA was obtained by acidizing NaHA with WV and then loaded onto BC, which successfully prepared a highly efficient modification agent for nickel-contaminated soil, namely biochar-humic acid material (BC-HA). The characteristics and parameters of BC-HA were obtained by FTIR, SEM, EDS, BET and XPS. The chemisorption of Ni(II) ions by BC-HA conforms to the quasi-second-order kinetic model. Ni(II) ions are distributed on the heterogeneous surface of BC-HA by multimolecular layer adsorption, which accords with the Freundlich isotherm model. WV promotes better binding of HA and BC by introducing more active sites, thus increasing the adsorption capacity of Ni(II) ions on BC-HA. Ni(II) ions in soil are anchored to BC-HA by physical and chemical adsorption, electrostatic interaction, ion exchange and synergy.

Antibiotic residues may be very harmful in aquatic environments, because of limited treatment efficiency of traditional treatment methods. An electrochemical system with a Ti-based SnO2–Sb–Ni anode was developed to degrade a typical antibiotic chloramphenicol (CAP) in water. The electrode was prepared using a sol–gel method. The performance of electrode materials, impact factors and dynamic characteristics were evaluated. The Ti-based SnO2–Sb–Ni electrode was compact and uniform as shown by characterization using SEM and XRD. The electrocatalytic oxidation of CAP was carried out in a single-chamber reactor by using a Ti-based SnO2–Sb–Ni electrode. For 100 mg L−1 CAP, the CAP removal ratio of 100% and the TOC removal ratio of 60% were obtained at the current density of 20 mA cm−2 and in a neutral electrolyte at 300 min. Kinetic investigation has shown that the electro-oxidation of CAP on a Ti-based SnO2–Sb–Ni electrode displayed a pseudo-first-order kinetic model. Free radical quenching experiments presented that the oxidation of CAP on Ti-based SnO2–Sb–Ni electrode resulted from the synergistic effect of direct oxidation and indirect oxidation (·OH and ·SO4−). Doping Ni on the Ti/SnO2–Sb electrode for CAP degradation was presented in this paper, showing its great application potential in the area of antibiotic and halogenated organic pollutant degradation. HIGHLIGHTS Ti/SnO2–Sb–Ni anodes were first applied to remove CAP by electrocatalytic oxidation.; The removal ratios of CAP and TOC by anodic oxidation and cathodic reduction were first compared.; The degradation of CAP on the Ti/SnO2–Sb–Ni electrode results from the synergistic effect of direct oxidation and indirect oxidation (·OH and ·SO4−). ·SO4− and direct oxidation contributed much to the degradation of CAP.;

Soil contaminations by heavy metals near oilfields have been widely reported and are causing great concern. Thus, it is highly desirable to develop cost-effective materials and methods to avoid heavy metal residues contaminating soil and food. An effective, environmentally friendly, and inexpensive remediation material for heavy metal-polluted soil was designed and prepared using biochar (BC) combined with humic acid (HA) resulting from sodium humate (NaHA) simply reacting with wood vinegar (BHW). After adding BHW, the chemical fractions of copper and cadmium in the soil undergo larger changes. Meanwhile, the availability of heavy metals decreases. The maximum adsorption capacity of copper and cadmium in the soil using the BHW is larger than that only using biochar. The adsorption kinetics ensures that the adsorption process of Cd2+ and Cu2+ ions on BHW is chemical adsorption, which is best fitted using the pseudo-second-order rate equation. The thermodynamics guarantees that the metal ions adsorb on the heterogeneous surface of BHW in multilayer, which is credited to the enhancement of oxygen-containing groups in the biochar combined with the humic acid. The remediation material BHW holds promise for the immobilization of heavy metal in the soils and could be recommended based on its economic feasibility, high efficacy, and environmental safety.

Biochar (BC) combined with humic acid (HA) and wood vinegar (WV) was designed and prepared as an inexpensive, effective, and environmentally friendly immobilization material (BHW) for metal-polluted soil. The influences of the wood vinegar and humic acid on the immobilization properties and adsorption mechanism of this new material were also investigated. The remediation performance was evaluated using a laboratory-made, nickel-contaminated soil with a Ni2+ concentration of 200 mg per kg surface soil (top 20 cm from agricultural land). The results indicated that the immobilization ratio sequence of nickel (II) in the soil was BC

A permeable reactive barrier (PRB) remediation test trough with coarse sand-supported zero-valent iron (ZVI) composite filler was designed and built. Considering the convection-dispersion and chemical reaction of 2,4-dichlorophenol (2,4-DCP) in groundwater, a coupled model of chemical reaction and solute transport of 2,4-DCP was built. The adsorption kinetics data of 2,4-DCP were fitted, the results showed the pseudo-second-order kinetic model could better describe 2,4-DCP adsorption process than the pseudo-first-order kinetic model. The model parameters were determined by static adsorption test and continuous flow dynamic tracer test. Compared with the linear model and the Langmuir model, the Freundlich model fits better with the adsorption test data, it shows that the adsorption of 2,4-DCP by coarse sand and coarse sand-supported ZVI filler was more in line with the Freundlich model. A Freundlich model showed a satisfactory fit to the equilibrium adsorption data with a correlation coefficient R² = 0.968 for coarse sand and R² = 0.954 for coarse sand-supported ZVI. The adsorption coefficient KF of 2,4-DCP on coarse sand and coarse sand-supported ZVI are 4.456 × 10–6 and 0.00846 respectively, the dispersion coefficient is 0.345 cm²/min, the porosity is 0.38, the specific yield is 0.1, the permeability coefficient is 4.15 × 10–2 cm/s, and the seepage velocity is 1.245 × 10–4 cm/s. The FEMWATER software and the TOUGHREACT software are used to calculate the coupling model to simulate the migration and transformation process of 2,4-DCP in groundwater. The results show that the calculated values by software TOUGHREACT do not agree well with the measured values for the failure zone of composite filler, the values calculated by software FEMWATER has better fitting effect with the measured values. [ABSTRACT FROM AUTHOR]

Cu-Sn-Bi layer coated on Ti substrate was prepared using electrodeposition method and applied as cathode material for electrochemical reduction of nitrate in this research. Linear sweep voltammetry (LSV), chronoamperometry (CA), scanning electron microscope (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) were used to scrutinize the electrochemical performance and the cathode materials. LSV results illustrated that Cu-Sn-Bi cathode possessed the ability for nitrate reduction. Preparation conditions including deposition time, current density, temperature and the content of Bi were optimized based on NO3-N removal and byproducts selectivity. Results showed that the cathode with Bi content of 3.18 at.%, and electrodepositing at current density of 6 mA cm-2, 35 °C for 30 min achieved the best performance during the experiment. The increase of Bi content could improve the electrocatalytic activity and stability of the cathode. Compared with other common researched cathodes (Cu and Fe), Cu-Sn-Bi (3.18 at.%) exhibited better performance, i.e. the highest NO3-N removal of 88.43% and the selectivity of harmless N2 was 77.80%. The kinetic studies showed that the reduction of nitrate on Cu-Sn-Bi followed pseudo-first-order kinetics. [ABSTRACT FROM AUTHOR]