SciELO - Scientific Electronic Library Online

 
vol.105 número7-8N,N'-diisopropylthiourea and N,N'-dicyclohexylthiourea zinc(II) complexes as precursors for the synthesis of ZnS nanoparticles índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados

Artigo

Indicadores

Links relacionados

  • Em processo de indexaçãoCitado por Google
  • Em processo de indexaçãoSimilares em Google

Compartilhar


South African Journal of Science

versão On-line ISSN 1996-7489

Resumo

PETRIK, L.. The influence of cation, anion and water content on the rate of formation and pore size distribution of zeolite ZSM-5. S. Afr. j. sci. [online]. 2009, vol.105, n.7-8, pp. 251-257. ISSN 1996-7489.

Rapid synthesis and high mesoporosity of ZSM-5 is promoted by altering a fixed molar regime with respect to anion and cation type and water content only. This study shows that merely changing the cation and anion types, accompanying the hydroxide and alumina (Al) sources, respectively, has an impact on the characteristics of ZSM-5. Under identical and replicated preparation and testing conditions, the synthesis time, Al incorporation, product yield, acidity, morphology, pore size distribution and catalytic activity were affected. An ion pair combination of Na+/NO3- allowed the formation of ZSM-5 with enhanced mesoporosity within 3 h in a high-water environment, whereas ZSM-5 prepared with the Na+/SO42- combination had enhanced n-hexane cracking activity. Use of a K+/NO3- ion pair combination in a high-water environment resulted in slower time of formation and larger ZSM-5 crystals with extra-framework Al, loss of acidity, lower surface areas and reduced n-hexane cracking activity. The sulphate anion inhibited the incorporation of Al in ZSM-5 products in low-water environments. Low-water levels increased the time of formation of ZSM-5.

Palavras-chave : zeolite ZMS-5; synthesis; cation; anion; acidity; porosity; extra-framework aluminium; n-hexane cracking activity; sulphate; nitrate.

        · texto em Inglês     · Inglês ( pdf )

 

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License