Студенттер мен жас ғалымдардың «фараби әлемі» атты халықаралық ғылыми конференциясы
MODIFIED BETA ZEOLITE SYNTHESIS AND APPLICATIONS
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Сборник конф Фараби Әлемі 2023 химфак-печать
| MODIFIED BETA ZEOLITE SYNTHESIS AND APPLICATIONS
Seitova D. A. 1,2 , Rymzhanova Z. K. 1,2 , Omirzakova A.T. 2,3 Research supervisor: Vassilina G.K. 1,2 1 Al-Farabi Kazakh National University, 2 Society of Petroleum Engineers International, 3 Nazarbayev University A dual-template strategy with monoethylene glycol (MEG) and tetraethyl ammonium hydroxide (TEAOH) was employed to synthesize the β-zeolite nanocrystal aggregates with ultrafine and hierarchical structure micropores combined with intramesopores and intermesopores), and the particle size of aggregates and the nanocrystal size of β-zeolite can be systematically tailored by tuning the molar ratios of TEAOH/MEG on the non -templating route → the controlled crystallization process → the dry-gel method. In the nitrates reduction reaction, the applied β-zeolite nanocrystal aggregates synthesized in the presence of MEG exhibited outstanding activity and resistance to deactivation under acidic reaction conditions, and the lifetime of BEA-MEG-5 was extended by 10 times compared with the beta zeolite without modification, indicating that the additional MEG played the role of crystal growth inhibitors to reduce the size of nanocrystals, which increased the amount of accessible external Bronsted acid sites and effectively enhanced the diffusion properties. In addition, the resultant β-zeolite nanocrystal aggregates also demonstrated robust regeneration performance which identified a facile and effective route to directly prepare β-zeolite nano-crystal aggregates with excellent catalytic properties in the nitrate’s reduction in aqueous medium. The dual-template strategy by MEG and TEAOH allowed to keep hydrophilicity of β-zeolite for the application in the nitrates remediation in aqueous phase by metals impregnation on the surface of synthesized β-zeolite. The Bronsted acid sites defined the selectivity of nitrates reduction to the nitrogen gas release which is nitrates remediation, the nitrogen selectivity was 99.8% over the 0.2% of ammonium selectivity. The zeolite structures ratio was SiO 2 :0.06Na 2 O:0.01Al 2 O 3 :0.25TEA 2 O:4C 2 H 5 OH:80H 2 O:xMEG where the Si/Al=100 and H 2 O/Si=80, x – variated in the range of 0-9. Secondly, the β-zeolite synthesis time was shorted from 9 days into 20 hours totally. During the synthesis time reduction, the b-zeolite characteristics were kept. Synthesized BEA-MEG-4,5,6 were also nanocrystals as BEA when other forms were amorphous by XRD analysis results. The particle size was decreased before BEA-MEG-5 and after жүктеу/скачать 2,6 Mb. Достарыңызбен бөлісу:
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