[Spatio-temporal Change in City-level Greenhouse Gas Emissions from Municipal Solid Waste Sector in China During the Last Decade and Its Potential Mitigation].

The waste sector is a significant source of greenhouse gas(GHG) emissions and clarifying its emission trends and characteristics is the premise for formulating GHG emission reduction strategies. Using the IPCC inventory model, the GHG emissions from the municipal solid waste(MSW) sector in China during 2010 to 2020 were estimated. The results showed that GHG emissions increased from 42.5 Mt in 2010 to 75.3 Mt in 2019, then decreased to 72.1 Mt in 2020. MSW landfills were the main source of GHG emissions. Further, with the increase in the proportion of waste incineration, the proportion of GHG incineration increased rapidly from 16.5% in 2010 to 60.1% in 2020. In terms of regional distribution, East and South China were the regions with the highest emissions, and Guangdong, Shandong, Jiangsu, and Zhejiang were the provinces with the largest GHG emissions. Implementing MSW classification, changing the MSW disposal modes from landfilling to incineration, improving the LFG collection efficiency of landfills, and using biological functional materials as the cover soil to strengthen the methane oxidation efficiency are the main measures to achieve GHG emission reduction in waste sectors.

[Influence of the Classification of Municipal Solid Wastes on the Reduction of Greenhouse Gas Emissions: A Case Study of Qingdao City, China].

The municipal solid waste (MSW) sector is an important source of greenhouse gas (GHG) emissions. MSW classification can achieve waste reduction and improve resource utilization. However, few studies have investigated the effects of MSW classification on GHG emission reduction. Therefore, the GHG emissions under different MSW disposal modes before and after classification were studied based on the life cycle assessment method in the four districts of Qingdao City. The results showed that MSW classification could significantly reduce the GHG emissions during the whole MSW treatment process. The net carbon emissions(in CO2/MSW)during the whole process of waste treatment for mode 1 (mixed collection+landfill), mode 2 (mixed collection+incineration), mode 3 (waste classification+anaerobic digestion of food waste and other incineration), and mode 4 (waste classification+anaerobic digestion of food waste, recycling of recyclable waste, and other incineration) were 686.39, -130.12, -61.88, and -230.17 kg·t-1, respectively. Improving the classification efficiency of food waste had no significant impact on carbon emissions. The reduction in carbon emissions increased linearly with the improvement of waste recycling efficiency. For every 10% increase in the recovery efficiency of recyclable waste, the net carbon emission decreased by 26.6%(16.5 kg·t-1). Appropriate separation of food waste, improving the recycling efficiency of recyclable waste, and reducing the leakage rate of biogas from anaerobic digestion are feasible strategies to reduce carbon emissions from MSW disposal units through the classification of MSW.

A molecular crowding thermo-switchable chiral G-quartet hydrogel with circularly polarized luminescence property.

A novel helix hydrogel with a G-quartet structure was synthesized from guanosine (Gua) and its derivative 5'-guanosine monophosphate (5'-GMP) under a molecular crowding environment. The chirality of the hydrogel is adjusted by controlling the gelling speed. The chiral hydrogel can induce an achiral dye Thioflavin T (ThT) to realize circularly polarized fluorescence (CPL). The CPL dissymmetry factor |glum| of the dye-hydrogels can reach 3 × 10-2 and can be switched easily.

Dual Confinement of CoSe2 Nanorods with Polyphosphazene-Derived Heteroatom-Doped Carbon and Reduced Graphene Oxide for Potassium-Ion Batteries.

High-capacity and highly stable anode materials are some of the keys to the realization of the application of potassium-ion batteries (PIBs). Cobalt diselenide (CoSe2) has been regarded as a high-potential anode material for PIBs. However, solving the problems of sluggish kinetics and large volumetric expansion during intercalation/deintercalation of K+ ions is always very challenging in terms of cobalt diselenide-based anode materials. Herein, reduced graphene oxide-encapsulated polyphosphazene-derived S, P, and N codoped carbon (SPNC)-coated CoSe2 nanorods (CoSe2⊂SPNC⊂rGO) were designed as PIB anode materials. CoSe2⊂SPNC⊂rGO delivers an excellent reversible capacity of 287.2 mAh g-1 at 100 mA g-1. Benefiting from the coating of heteroatom-doped carbon and encapsulation of rGO, the CoSe2⊂SPNC⊂rGO anodes exhibit a remarkable rate capability (100-1500 mA g-1 current density) and high stability (208.8 mAh g-1 after 500 cycles at 500 mA g-1). The results demonstrate that S, P, and N codoping in carbon layers provides active sites for K+ ion storage and increases the electrical conductivity. More importantly, the dual confinement of CoSe2 nanorods with carbon layers and rGO significantly reduced the volume expansion and kept the electrode structural integrity with repeating intercalation/deintercalation of K+ ions.

Kinetic control of chirality and circularly polarized luminescence in G-quartet materials.

The formation of chirality of G-quartet materials has been of concern for a long time, however, the helix-handedness of G-quartet materials is still ambiguous, as well as the novel circularly polarized luminescence (CPL) properties. Here, we demonstrated that the handedness of G-quartet materials highly depends on their formation kinetics. By controlling the temperature or the initial concentration of reactants, we found that right-handed helical G-quartet nanostructures were synthesized in the slow process, while left-handed structures were synthesized in the fast process via orderly stacking. The phenomenon can be explained by the theory of kinetic trapping, in which a slow process leads to the thermodynamic equilibrium, while a fast process results in the kinetic trap state. Furthermore, the first kinetic trapping-controlled reversal CPL system was designed in G-quartet materials via chirality transfer, which has potential applications in CPL materials design and application.

Right-/left-handed helical G-quartet nanostructures with full-color and energy transfer circularly polarized luminescence.

Right (R)- and left (L)-handed helical G-quartet nanostructures were synthesized for the first time simultaneously via the self-assembly of 5'-guanosine monophosphate (GMP), the helical handedness of which is well regulated by metal ions. These g-nanostructures were further applied as circularly polarized luminescence (CPL) templates to realize full-color R-/L-CPL and Förster resonance energy transfer CPL. The glum value reached 10-2, indicating their excellent template function for CPL materials design and application.