Angstrom-level pore regulation in a triazolate-based MOF is achieved through a reorientation of triazolate rings induced by amino functionalization. The resulting pore contraction effectively suppresses CH4 diffusion while preserving CO2 transport, leading to markedly enhanced CO2/CH4 selectivity.

The efficient separation and enrichment of methane (CH4) from low-concentration coalbed methane (CBM) are of great significance for enhancing CBM utilization efficiency and promoting the development of low-carbon clean energy. To address this practical need, this study synthesized a tailored chlorinated metal-organic framework (MOF), PCP-IPA-Cl, and systematically evaluated its CH4/N2 separation performance through a combination of static adsorption measurements, density functional theory (DFT) calculations, dynamic breakthrough experiments, and multiple adsorption-desorption cycling tests. Endowed with its optimized pore structure and chlorinated channel environment, PCP-IPA-Cl exhibits excellent CH4/N2 separation performance and regeneration stability: at 298 K and 1 bar, it achieves a high CH4 adsorption capacity of 21.27 cm3/g with a low N2 uptake of only 5.29 cm3/g, and compared with its unchlorinated analog PCP-IPA, the CH4/N2 selectivity is markedly improved from 5.4 to 9.0. DFT calculations reveal that the introduction of–Cl groups creates additional preferential adsorption sites for CH4 molecules, strengthening host-guest interactions and thus enhancing separation efficiency. Furthermore, breakthrough experiments confirm its excellent dynamic separation ability, and cyclic tests demonstrate that PCP-IPA-Cl can be fully regenerated via helium purging within just 5 min. These findings collectively demonstrate that PCP-IPA-Cl is a promising and regenerable adsorbent for the efficient enrichment and utilization of low-concentration CBM.

Achieving low-energy and high-efficiency sieving of nitrogen rejection from methane in natural gas purification processes requires precise control of material pore size with a resolution of 0.1-0.2 Å, which is highly challenging. Here, we report a novel adsorbent (MOR-Cu), a mordenite with copper introduced in situ via high-temperature crystallization, enabling precise sieving of nitrogen and methane by the appropriate pore size and pore geometry. Refinement of the crystal structure shows that the higher crystallization temperature changes the position of the copper component, increasing pore volume and enhancing nitrogen adsorption capacity and kinetics. MOR-Cu-210 obtained by crystallization at 210 °C exhibits a record nitrogen adsorption capacity (0.74 mmol g-1) and nitrogen/methane uptake ratio (62.1) at 298 K and 1 bar, breaking the bottleneck of adsorption capacity and selectivity. Cyclic gas adsorption tests and column breakthrough experiments confirm high separation performance and stable recyclability.

A mmonia nitrogen contamination poses severe threats to aquatic ecosystems and human health, with its induced eutrophication requiring urgent and efficient remediation. Adsorbents are effective in removing aqueous ammonia nitrogen, but existing adsorbents are costly and inefficient. It is important to develop a low-cost and efficient adsorbent. Corn straw is a kind of cheap and easy-to-obtain material. In this study, biochar prepared from corn straw was used as an adsorbent for ammonia nitrogen. In order to explore biochar with high adsorption ability, sodium carbonate, magnesium chloride, and potassium hydroxide were used as additives. The results show that the magnesium chloride-modified biochar (MBC) demonstrates remarkable advantages: a carbon yield of 51.901 ΔH^0 value confirms the endothermic nature of the adsorption process. Both pseudo-second-order kinetic (R2 0.992–0.999) and Langmuir isotherm (R2 0.936–0.996) models effectively describe the adsorption kinetics and equilibrium, respectively, indicating predominant monolayer chemisorption on homogeneous surfaces. Mechanistic analyses through characterization demonstrate that ammonia nitrogen removal is governed by pore filling, complexation, cation-π interactions, cation exchange, and electrostatic attraction.

Efficient nitrogen removal from aquaculture wastewater is crucial for environmental sustainability. A novel strain, Marinobacterium maritimum 5-JS, exhibiting HN-AD capabilities, was isolated from a sea cucumber aquaculture pond. This strain demonstrated remarkable nitrogen removal efficiencies, achieving nearly 100% elimination of NH4+-N, NO3--N and NO2--N within 18 h. Strain 5-JS preferentially utilizes NH4+-N in simultaneous nitrification and denitrification processes, with optimal removal achieved using sodium citrate as a carbon source, a C/N ratio of 11, pH 8.0, and at a temperature of 30 °C. The metabolic pathway of strain 5-JS was elucidated, indicating its adaptability to high concentrations of Mg2+, Fe2+, and Mn2+ (up to 50 mg/L). When introduced into mariculture wastewater, strain 5-JS rapidly reduced concentrations of all three nitrogen compounds to undetectable levels within 8 h. These findings highlight the exceptional nitrogen removal capabilities of strain 5-JS and its potential for application in the biological treatment of aquaculture wastewater.

Aerobic granular sludge (AGS) systems face challenges in achieving simultaneous nitrification, denitrification, anaerobic ammonium oxidation (anammox), and phosphorus removal (SNDAPR) under low-carbon conditions. The role of aeration strategies in regulating these processes remains unclear. Two sequencing batch reactors (R1: 90-min oxic/DO=2 +/- 0.3 mg/L; R2: 180-min oxic/DO=1 +/- 0.3 mg/L) were operated for 290 days. Granulation dynamics, nutrient removal performance, and microbial community evolution were systematically analyzed using chemical measurements, 3D-EEM, metagenomics, and functional gene prediction. R1 achieved superior total inorganic nitrogen (TIN) removal (81.4 % vs. R2's 77.8 %) with 93.4 % phosphorus removal, attributed to enrichment of denitrifying glycogen-accumulating organisms (Candidatus_Competibacter: 45.23 %) and potential anammox activity (Candidatus_Kuenenia: 0.05 %). Short-aeration/high-DO promoted protein-rich EPS (25.66 mg/g VSS), enhancing granule stability (G ': 15.5 KPa). Long-aeration/low-DO favored dissimilatory nitrate reduction to ammonium (DNRA) via nrfA gene expression. This study demonstrates that short-aeration/ high-DO strategies optimize SNDAPR performance by synergizing DGAOs and anammox bacteria, providing a novel operational framework for low-carbon wastewater treatment.

Heterotrophic nitrification aerobic denitrification represents an exceptionally efficient biological process for nitrogen removal, where nitrate reductase plays a pivotal role as the initial step. Using a crude enzyme solution, AtNR01 was able to degrade 80 % of 1 mg/mL NO3--N within 20 min. Notably, AtNR01 can maintain robust performance over a wide range of temperatures and pH levels. In addition, when AtNR01 and its engineering bacteria are applied to the treatment of aquaculture wastewater, the degradation rate of NO3--N can reach about 85 % within 10 h under the condition of low temperature 10 °C. Molecular docking results indicated that Nitrate binds to mvrA by the amino acid residues Ser 68 A and Phe 81 A and forms hydrogen bonds that help improve the stability of binding. These findings underscore the significant application potential and economic value of AtNR01 and its engineered counterpart in the treatment of low-temperature aquaculture wastewater.

The coupling of DAP (2.9–29 wt%) and pre-carbonization (300 °C, 1 h) of a woody biomass waste (fast growing) was aimed to improve the carbon yield for pyrolysis technology. After the pretreatment, the pyrolysis experiment was performed at 500–900 °C under hypoxic conditions. The introduction of DAP (2.9%) could enhance the solid yields 2 times for biomass, and the calorific value was elevated from 22.57 kJ/kg for the carbonized biomass to 24.67 kJ/kg in carbonization. The further pyrolysis results showed that the comparable solid yield (85%), gas yield (4.1%), and liquid yield (21%) of CPDP were obtained by the above modification of biomass. The phenolic and toluene compounds of the tar were reduced by 37.3% and 7%, the temperature of the main gas precipitation peaks was decreased by 78 °C, and the released of methane was more than 3 times. This work for the first time proves the effectiveness of improving the carbon fixation and deoxidation performance from biomass via the pretreatment by DAP impregnation and the carbonization. Graphical Abstract

Abstract Polyvinyl chloride (PVC) is a polymer made by free radical polymerization and is a common plastic raw material in our life. Currently, one of the ways to recycle PVC is to burn and pyrolysis it, and the HCl produced by pyrolysis has adverse effects on the environment and the human body. The objective of this research was to the pyrolysis of PVC during slow pyrolysis in a tubular heating furnace. Moreover, to evaluate the effect of different temperatures with different calcium oxide (CaO) addition ratios on the removal of HCl generated by PVC pyrolysis. In addition, the tar and gas produced by pyrolysis were also analyzed. Firstly, the solid-phase products resulting from the co-pyrolysis of PVC with CaO addition were observed using scanning electron microscopy (SEM) and X-ray energy spectrometry (EDS). Next, the crystalline content of the solid phase products was analyzed using X-ray diffractometry (XRD). FTIR analysis of the liquid-phase products of PVC pyrolysis under CaO addition was performed. The gas phase products were analyzed by GC for common gas compositions. The results showed that more reactive sites were provided at a Ca/Cl addition ratio of 2:1. The peak value of alkaline calcium chloride was highest at 500°C, which indicates that the removal of HCl is best at 500°C. It was observed that the HCl removal efficiency reached 93.4% at a Ca/Cl ratio of 2:1 at a temperature of 550°C. This study provides a new theoretical basis for the pyrolytic removal of HCl from PVC.

As a newly identified nitrogen loss pathway, the nitrate-dependent ferrous oxidation (NDFO) process is emerging as a research hotspot in the field of low carbon to nitrogen ratio (C/N) wastewater treatment. This review article provides an overview of the NDFO process and summarizes the functional microorganisms associated with NDFO from different perspectives. The potential mechanisms by which external factors such as influent pH, influent Fe(II)/N (mol), organic carbon, and chelating agents affect NDFO performance are also thoroughly discussed. As the electron-transfer mechanism of the NDFO process is still largely unknown, the extensive chemical Fe(II)-oxidizing nitrite-reducing pathway (NDFOchem) of the NDFO process is described here, and the potential enzymatic electron transfer mechanisms involved are summarized. On this basis, a three-stage electron transfer pathway applicable to low C/N wastewater is proposed. Furthermore, the impact of Fe(III) mineral products on the NDFO process is revisited, and existing crusting prevention strategies are summarized. Finally, future challenges facing the NDFO process and new research directions are discussed, with the aim of further promoting the development and application of the NDFO process in the field of nitrogen removal.

To be a sustainable development of direct coal liquefaction, the evaluation of hydrogen-donating activity of hydrogen-donor solvents (H-donors) are one of key impacts on determining the distribution and quality of liquids. However, it is hardly to precisely assess the capability of H-donors through experiments alone. The density functional theory calculations and transition state theory were employed quantitatively to analyze the rate constant of hydrogen transfer from H-donors to coal radicals. Results indicated that hyperconjugation and ring strain play important roles in the hydrogen-donating activity of H-donors. Stronger hyperconjugation is from lower hydrogenation depth, the 1-methyl group was substituted at the α position of aromatics, shorter chain length and isomerization of alkyl substituent. Due to bigger ring strain, the hydrogen-donating activity of H-donors containing five-membered saturated rings are lower than that of the hydrogenated aromatics with similar structures. Theoretical analysis is confirmed by experimental data in the literature.

Heterotrophic-autotrophic denitrification reduces the cost of wastewater treatment and the risk of excess chemical oxygen demanded (COD) in the effluent. A mixotrophic denitrification system involving mixed heterotrophic and ferrous autotrophic bacteria was investigated to treat low-C/N ratio (C/N, defined as chemical oxygen demand (COD)/total nitrogen (TN)) wastewater with pyrite and organic carbon as electron donors. The system yielded effluent total nitrogen (TN) of 0.38 mg/L in 48 h due to a synergistic effect when the C/N ratio was 0.5 and influent nitrate nitrogen (NO3--N) was 20 mg/L; this TN value was significantly lower than those of the heterotrophic system (14.08 mg/L) and ferrous autotrophic system (12.00 mg/L). The highest abundance of the narG gene was observed in the mixotrophic denitrification system, along with more abundant microbial species. The dominant denitrification bacteria in each system included Thaurea, Ferritrophicum, Pseudomonas, and Thiobacillus, which varied with the initial inoculum source and the environment. Nevertheless, the abundance of the heterotrophic bacteria Thaurea decreased with prolonged operation of the systems. Together, these results implied that the simultaneous heterotrophic and FeS2-based ferrous autotrophic denitrification process can be an alternative approach for the treatment of low-C/N ratio wastewater.

Based on the national strategy of "new urbanization", from the perspective of urban and rural integration, industrial interaction, economy and intensification, this paper proposes to vigorously promote the industrialization planning of urban and rural housing based on SI system, do a good job in the production of building structural parts from the perspective of building industrialization, extend to the internal filling parts, and do a good job in the internal filling system from the perspective of housing industrialization. At the moment of "Rural Revitalization" strategy, we should first develop the SI system multi-storey industrialized housing to meet the needs of rural areas. At the same time, we put forward the development path of China's urban and rural housing industrialization.

Spatial Structure Reconstruction In article number 2100866, Jiangfeng Yang, Libo Li, and co-workers, through optimized spatial structure reconstruction, build TYUT-96Cr, composed of three kinds of small pore cages using Cr and trimesic acid. Benefitting from the high-density open Cr sites in the structure, this material features record N2 adsorption volume capacity and N2/O2 separation selectivity, and is practically useful for upmarket industrial applications.

In this study, three solid-phase iron sources-FeS, FeCO3, and sponge iron-were used to investigate the autotrophic denitrification efficiency in low-carbon-to-nitrogen (C/N) wastewater. Among these iron sources, FeS obtained the best efficiency, with a nitrate removal of 96% at 120 h under C/N=1 and NO3--N=40mgL-1. Then, batch experiments with FeS as an electron donor were conducted to evaluate the effect of different influent C/N ratios and NO3--N concentrations. According to the results of the experiments, the nitrate removal efficiency of the mixotrophic system was greater than that of the pure autotrophic system under low-C/N ratios, and the TN (total nitrogen) removal efficiency was also enhanced. In the mixotrophic system, the nitrate removal reached 98% in 48 h under a C/N ratio of 1, and NO3--N was in the range of 20mgL-1 to 40mgL-1. Additionally, some accumulation of ammonia was observed in the nitrogen conversion process. According to microbial analysis, the synergistic action of heterotrophic and autotrophic denitrifiers improved nitrate removal.

In the present paper, AlF3-YbF3 : Er3+ was prepared by high temperature solid phase reaction, and the concentration effect of Er3+ on luminous intensity of phosphors was studied. The crystal structures of the phosphors were characterized by means of X-ray diffraction (XRD), and the upconversion luminescence properties of phosphor were studied by fluorescence emission spectra. Upon 980 nm excitation, when the Er3+ concentration was fixed to be 0.7 mol%, the maximum red emission intensities can be obtained in the sample. Furthermore, the research results showed that the fitted slope for red transition emission was 2.24, indicating that red emission is due to a two-photon excitation process.

Lanzhou is one of the seriously polluted cities in Northwest China. Dustfall samples collected in Lanzhou and the countryside Huanghuatan were studied using magnetic methods. The results reveal that the content of magnetic mineral in dustfall samples from Lanzhou is much higher than that of Huanghuatan. At the same time, it has a much higher lever in winter than that of other seasons. The main magnetic minerals in the dustfall from both places are magnetite, maghemite and hematite, and the main magnetic grain sizes in dustfall samples are mainly pseudo single-domain(PSD) and multi-domain(MD). Although the air in Lanzhou is polluted seriously, the air quality has been improved greatly during the past decades and controlled well in recent years. Compared with other cities, air pollution in Lanzhou is affected significantly by urban terrain. This research also reveals that environmental magnetism has become a more and more important method in air pollution study.

Polyvinyl chloride (PVC) is a polymer made by free radical polymerization and is a common plastic raw material in our life. Currently, one of the ways to recycle PVC is to burn and pyrolysis it, and the HCl produced by pyrolysis has adverse effects on the environment and the human body. The objective of this research was to the pyrolysis of PVC during slow pyrolysis in a tubular heating furnace. Moreover, to evaluate the effect of different temperatures with different calcium oxide (CaO) addition ratios on the removal of HCl generated by PVC pyrolysis. In addition, the tar and gas produced by pyrolysis were also analyzed. Firstly, the solid-phase products resulting from the co-pyrolysis of PVC with CaO addition were observed using scanning electron microscopy (SEM) and X-ray energy spectrometry (EDS). Next, the crystalline content of the solid phase products was analyzed using X-ray diffractometry (XRD). FTIR analysis of the liquid-phase products of PVC pyrolysis under CaO addition was performed. The gas phase products were analyzed by GC for common gas compositions. The results showed that more reactive sites were provided at a Ca/Cl addition ratio of 2:1. The peak value of alkaline calcium chloride was highest at 500°C, which indicates that the removal of HCl is best at 500°C. It was observed that the HCl removal eciency reached 93.4% at a Ca/Cl ratio of 2:1 at a temperature of 550°C. This study provides a new theoretical basis for the pyrolytic removal of HCl from PVC.