Coalbed methane (CBM) is a kind of unconventional gas. CBM often contains a great deal of air when it comes out of the well. So, it must be condensed and purified before it can be applied. In this paper, raw clinoptilolite (Cp) was treated with grinding, gravimetric concentration, and ion-exchange using different aqueous solutions of salts. Then, the modified Cp powder was prepared into particles as adsorbents. Then, the adsorbents were used for nitrogen/methane separation in pressure swing adsorption (PSA) at the same condition of 0.2 MPa and 298 K. Research results indicated that there were micropores and lots of mesopores in the Cp, and the pores were mainly slit holes formed by sheet stacking. The adsorbents of NH₄-Cp, Cs-Cp, and Cu-Cp showed good equilibrium selectivity for CH₄, and the equilibrium separation factors of CH₄ and N₂ were 2.56, 2.31, and 1.95, respectively. The adsorbents of Na-Cp and Ag-Cp showed good equilibrium selectivity for N₂, and the equilibrium separation factors of N₂ and CH₄ were 7.25 and 6.53, respectively. Consequently, the adsorbent of Na-Cp was suitable for nitrogen/methane mixture separation, which could make the concentration of methane concentrated from 19.7% to 30.72%.

Waste management poses escalating threats to environmental sustainability, particularly with municipal solid waste (MSW) growth. Incineration, a widely adopted method for reducing waste volume, produces millions of tons of municipal solid waste incineration fly ash (MSWIFA) each year. Despite its high toxicity and classification as a hazardous solid waste, its ultrafine particle size and pozzolanic activity offer potential for its use in construction materials. In this study, MSWIFA was used to replace 6%, 12%, 18% and 24% of cementitious materials, and the effect of MSWIFA substitution rate on the workability, mechanical properties, microstructure, and durability of UHPC was studied. Furthermore, the study assessed the solidification capacity of the UHPC for heavy metal ions and quantitatively analyzed its eco-economic benefits. The results show that, under standard curing conditions, substituting 12% of cementitious materials with MSWIFA significantly modified UHPC hydration, shortened setting time, reduced fluidity, and increased wet packing density. The 28-day compressive strength reached 134.63 MPa, comparable to the control group. Concurrently, fluidity, durability, and heavy metal leaching all met the required standards, with energy consumption reduced by 14.86%, carbon emissions lowered by 12.76%, and economic costs decreased by 6.41%. This study provides a feasible solution for recycling MSWIFA into non-hazardous concrete, facilitating sustainable hazardous waste management and mitigating heavy metal-related environmental pollution.

Low carbon, low cost and sustainability are important development trends of ultra-high-performance concrete (UHPC). In this study, municipal solid waste incineration bottom ash (MSWIBA) was used to replace 5%, 10%, 20% and 30% of quartz sand (QS), respectively, and the effect of the MSWIBA substitution rate on the workability, wet packing density, mechanical properties, shrinkage, resistance to chloride ion corrosion, and resistance to sulfate corrosion of UHPC was studied. The mechanism analysis was carried out by combining X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM) tests, and UHPC heavy metal leaching tests, environmental impact assessment, and economic analysis were conducted. Results show that the active silicon and aluminum components in MSWIBA reacted with cement hydration products to optimize the matrix density. MSWIBA has an internal curing effect, which is beneficial for reducing the shrinkage of UHPC. When the MSWIBA replacement rate is 10%, the 28-day compressive strength of MSWIBA-UHPC is 128.7 MPa, which is equivalent to the benchmark group. The fluidity, corrosion resistance and heavy metal leaching all meet the requirements. The energy consumption, carbon emissions and costs are reduced by 0.22%, 2.30% and 6.67%, respectively. The research results can provide a reference for the development of ecological UHPC with economic, low-carbon and environmental benefits, as well as the harmless disposal and resource utilization of hazardous wastes such as MSWIBA.