Biomass thermochemical conversion with in situ CO₂ capture is a promising technology in the production of high-quality gas. The adsorption competition mechanism of gas molecules (H₂O, CO₂, CO, CH₄, and H₂) on CaO-based catalyst surfaces was studied using density functional theory (DFT) and experimental methods. The adsorption characteristics of CO₂ on CaO and 10 wt % Ni/CaO (100) surfaces were investigated in a temperature range of 550–700 °C. The adsorption energies were increased and then weakened, reaching their maximum at 650 °C. The simulation results were verified by CO₂ temperature-programmed desorption (CO₂-TPD) experiments. By the density of states and Mulliken population analysis, CaO doped with Ni caused a change in the electronic structure of the O_surf atom and decreased the C–O bond stability. The molecular competition mechanism on the CaO-based catalyst surface was identified by DFT simulation. As a result, the adsorption energies decreased in the following order: H₂O > CO₂ > CO > CH₄ > H₂. The increase of CO₂ adsorption energy on the 10 wt % Ni/CaO surface, compared with the CaO surface, was the largest among those of the studied molecules, and its value increased from 1.45 eV to 1.81 eV. Therefore, the 10 wt % Ni/CaO catalyst is conducive to in situ CO₂ capture in biomass pyrolysis.

This study investigated the hydrochar-based porous carbon prepared by combining the technical route of hydrothermal carbonization (HTC) + chemical activation. The hydrochar morphology was adjusted by changing the activation reaction conditions and adding metal salts. Experiments showed that the activation of KHCO₃ significantly increased the specific surface area and pore size of the hydrochar. Besides, oxygen-rich groups on the surface of the activated hydrochar interacted with heavy metal ions to achieve efficient adsorption. The activated hydrothermal carbon adsorption capacity for Pb²⁺ and Cd²⁺ ions reached 289 and 186 mg/g, respectively. The adsorption mechanism study indicated that the adsorption of Pb²⁺ and Cd²⁺ was related to electrostatic attraction, ion exchange, and complexation reactions. The “HTC + chemical activation” technology was environmentally friendly and effectively implemented antibiotic residues. Carbon materials with high adsorption capacity can be prepared so that biomass resources can be utilized with excessive value, as a consequence presenting technical assistance for the comprehensive disposal of organic waste in the pharmaceutical industry and establishing a green and clean production system.

The use of HZSM-5 and modified catalysts for the pyrolysis of lignin to produce aromatics has been extensively investigated. But certain limitations including catalyst deactivation and high-cost modifications still exist. A magnetic field (MF) was used to assist Fe and HZSM-5 catalytic lignin pyrolysis for aromatics production in this study. Product composition analysis revealed that the monocyclic aromatic hydrocarbon (MAH) and benzene, toluene, ethylbenzene, and xylene (BTEX) contents exhibited an upward trend in correlation with the MF intensity. The introduction of a MF significantly affects the improvement of the BTEX yield. Under the conditions of 80 mT MF intensity, 500 °C temperature and 50 mL min⁻¹ carrier gas flow rate, the MAH and BTEX contents reach 32.94% and 27.19%, while the BTEX yield reaches roughly 19.55 mg g⁻¹. Compared to no MF, these values rose by about 1.28, 1.36, and 1.94 times, respectively. Characterization results from XRD, XPS, TPO, N₂ adsorption–desorption, and NH₃–TPD tests showed that the MF facilitated the deoxidation and fragmentation of macromolecular oxygenates on the surface of Fe, promoting the ingress of smaller molecular compounds into the pores of HZSM-5 and boosting MAH production. Simultaneously, the MF impeded pore blockage in HZSM-5 and kept acidic sites from deactivating due to carbon deposition. This study lays a crucial groundwork for improving advanced technologies aimed at optimizing the utilization of organic solid waste.

The effects of ash and slag from a biomass power plant on the compressive strength, setting time and fluidity of the pastes of Portland cement (P.O) and sulfoaluminate cement (SAC) were studied, and the hydration products and microstructure at the age of 7 days were analyzed via XRD, SEM and other test methods. The results show that the compressive strength of the composite cementitious material decreases, the setting time prolongs and the fluidity increases with the increase in the ash and slag content in the power plant. The microscopic analysis shows that the ash and slag of the biomass power plant can promote the hydration of Portland cement and sulfoaluminate cement paste, and increase the generation of hydration products. The results showed that replacing SAC clinker with 20–30% biomass power plant ash (BPPA) decreased the cement strength, and that an appropriate amount of BPPA (10–15%) could significantly improve the mechanical strength of SAC blended cement. The compressive strength of blended BPPA composite cementitious material in 28 days could reach 60 MPa. This study provided solutions to utilizing the BPPA as a building material admixture to minimize the consumption of energy-intensive cement and to meet the growing needs of the construction industry.

Compound specific isotope analysis (CSIA) provides a valuable tool to identify multiple sources and to elucidate the underlying transformation processes of different organic contaminants in complex environments. Different from conventional isotope ratio mass spectrometry (IRMS) based techniques, a mid-infrared laser based analytical approach is newly developed in this study for gas chromatography (GC) separation and carbon CSIA of aromatic organic pollutants in water. The accuracy and precision of our method are evaluated by determining δ¹³C values of benzene, toluene, ethylbenzene and 1,2,4-trimethylbenzene dissolved in water. Headspace samples at microgram-per-liter aqueous concentrations are analyzed and the obtained precision is higher than 0.3‰ for all the target compounds. The accuracy of our method is cross validated by comparing with the conventional IRMS measurements, where the differences in δ¹³C values of the target compounds are within 0.5‰. The validated approach is applied to monitor the temporal trend of the carbon isotopic composition of 1,2,4-trimethylbenzene in drilling fluids collected during horizontal shale drilling processes. The increasing δ¹³C trend indicates carbon isotope sensitive processes likely caused by subsurface transformations of 1,2,4-trimethylbenzene. To the best of our knowledge, this is the first validated optical carbon CSIA approach proven to be applicable for a wide spectrum of organic compounds.

Helium is a scarce strategic resource. Currently, all economically valuable helium resources are found in natural gas reservoirs. Owing to helium’s different formation and migration processes compared to natural gas’s, the traditional method of collecting wellhead gas to detect helium concentration may miss helium-rich layers in the vertical direction, which will not only cause the waste of helium resources, but also restrict the study of helium migration and accumulation mechanisms. To solve this problem, we designed a helium detector based on a quadrupole mass spectrometer. Through the combination of different inlet valves, we avoided gas mixing between different vertical layers during the inlet process and realized high-spatial-resolution helium concentration detection. We applied the helium detector to the Dongsheng gas field in the northern Ordos Basin, and the instrumental detection results were consistent with the laboratory analysis results of the wellhead gas, which demonstrated the stability of the helium detector in the field environment and the reliability of the data. Meanwhile, the results showed that the distribution of helium in the plane is highly heterogeneous, and the natural gas dessert layers and the helium dessert layers do not coincide in the vertical direction. In addition, we found a good correlation between helium and hydrogen concentrations. Combining our results with previous data, we propose a hydrogen–helium migration and accumulation model, which enriches the understanding of helium accumulation mechanisms and provides a basis for future helium resource exploration.