Bio-oils are an important part of the future energy composition.

N-doped biochars (NPCs) derived from waste biomass are promising materials for the removal of acid gases, while waste biomass is a cheap and sustainable resource. Also, the incorporation of nitrogen (N), especially N-groups in the carbon lattice, has a positive effect on acid gas removal. The doped N improves the basicity of carbon surfaces and forms superoxide radicals, thus enhancing the adsorption and catalytic performance of carbon materials. However, the acid gas removal performance of NPCs is closely related to the resultant N functionalities. Understanding the mechanism of N incorporation is beneficial for the design of NPCs with outstanding performance. In this paper, the preparation of NPCs derived from waste biomass and their application in acid gas removal (i.e., CO₂, H₂S, SO₂, and NO_x) are reviewed. The N species on the NPC surfaces, the effects of synthesis strategies on N configuration and N content, and related N-doping mechanisms are summarized and discussed. Moreover, the application in acid gas treatment of waste biomass-based NPCs is presented in detail. Finally, we propose a prospective investigation into the application of waste biomass-derived NPCs in the acid gas removal and catalysis fields.

In this review, the H ₂ S/CH ₄ separation properties of polymer membranes are presented and a new upper bound is proposed. In view of the existing problems and development prospects of various membranes, the corresponding opinions and advices are given.

Novel biochar was prepared from plant-based biomass by the addition of nitrogen-containing phosphates (NCPs), including ammonia phosphate (AP), ammonia polyphosphate (APP) and urea phosphate (UP). The results demonstrated that with the addition of NCPs, the yield of biochar could be significantly increased from about 30% to up to about 60%. The pore structure of the biochar was significantly improved, and the AP-prepared biochar obtained a higher S_BET and V_tot of 798 m² g⁻¹ and 0.464 cm³ g⁻¹, respectively. Moreover, the surface chemistry of the NCP-prepared biochar was affected, and N heteroatoms could be successfully doped on the surface of biochar, up to 4.16%. Furthermore, through TG-FTIR and XPS analysis, some possible interactions between plant-based biomass and NCPs during the pyrolysis process were proposed to explore the mechanisms of the preparation process, including the P route and N route, in which the H₃PO₄ and NH₃ gradually generated during the heating process played the dominant roles for the high yield N-doped biochar. All the NCP-prepared biochar presented good toluene adsorption capacities from 175.9 to 496.2 mg g⁻¹, which were significantly higher than that of blank char (6.5 mg g⁻¹).