Boyang Xu,Jie Chen,Kai Wang,Pengfei Li,Le Kang,Huiling Du,Qianqian Liu,Xiaoqing Lian
The accumulation of organic pollutants and solid waste is one of the major environmental challenges faced globally. Establishing an efficient recycling system for solid waste and designing cost-effective, high-performance photocatalysts are urgent tasks for the removal of organic pollutants from water. This study utilizes coal gangue as the precursor to synthesize a coal gangue-based phosphorus–silicon–aluminum molecular sieve (SAPO-5) via hydrothermal synthesis. The resulting material was then composited with bismuth oxybromide (BiOBr) to form a novel BiOBr/coal gangue-based SAPO-5 nanocomposite. When the mass ratio of BiOBr to coal gangue-based SAPO-5 molecular sieve is 0.3, the synthesized nanocomposite exhibits excellent adsorption and photocatalytic performance for the removal of methylene blue, achieving a removal rate of 97.8% and the mineralization rate of 57.4% within 30 min. The superior performance can be attributed to the optimal pore size, rapid charge transfer rate, and high photogenerated charge density of the BiOBr/coal gangue-based SAPO-5 nanocomposite. The novel BiOBr/coal gangue-based SAPO-5 molecular sieve nanocomposite catalyst presents a new approach for the harmless treatment of organic dye wastewater and the high-value utilization of coal gangue.
Hierarchically structured SAPO-5 molecular sieve was synthesized by microwave-assisted ionothermal method in eutectic mixture solvent. Their porous texture and acid properties were characterized by nitrogen physisorption, SEM, TEM and NH 3 -TPD. The results show that the mesoporous volume of SAPO-5 can be tuned via simply varying the degree of supersaturation, the type of mineralizer or replacing partly succinic acid with sebacic acid. A lower degree of supersaturation and using ammonium fluoride as a mineralizer favor the synthesis of SAPO-5 with large mesoporous volume. Notably, the introduction of sebacic acid can lead to three-level micro-meso-macroporous structure (sample C1). Five typical samples were selected as catalysts and tested in the alkylation of benzene with benzyl alcohol. Among all catalysts, the sample C1, whose aspect ratio is the lowest, exhibited the best catalytic activity, giving a 91 % benzyl alcohol conversion. The diffraction peak intensity ratio of I 002 /I 100 was proposed to be a good indicator in fabricating a highly active SAPO-5 catalyst for this reaction.
SAPO-5 zeolite supported RuMn was a highly efficient catalyst for the aqueous-phase selective hydrodeoxygenation of guaiacol to cyclohexanol. The optimal catalyst achieved a high cyclohexanol yield of 93.7% at full guaiacol conversion under mild conditions, with a high TOF of 920 h -1 . Moreover, the catalyst displayed remarkable performance for the hydrogenation of phenol to cyclohexanol, where a 100% yield of cyclohexanol was obtained at a phenol-to-Ru molar ratio of about 17900. In particular, the catalyst exhibited excellent recyclability and could be recycled for 20 times without obvious activity loss. The as-prepared RuMn/SAPO-5 catalyst exhibited higher performance than most of the reported Ru-based catalysts.