Kinetic model for the isothermal activation of bentonite by sulfuric acid

Performance of phosphoric acid activated montmorillonite as buffer materials for radioactive waste repository

“…With the progress of activation, these sites transformed from the micropores to mesopores. Finally, with the decomposition of lattice structure at these locations, some of the mesopores disappear, leading to a drop in specific surface area [3].…”

“…The advantage of using chemical activation lies in that it can be carried out under mild conditions, minimizing further separation and regeneration processes. During acidification, the H + attack would induce the leaching of mineral impurities, the disaggregation of clay particles, and the dissolution of the external layers [3]. Also, the H + attack is accompanied with the replacement of exchangeable cations that are originally adsorbed on the clay surface to compensate the negatively charged clay surface.…”

“…For example, the catalytic property of montmorillonite could be greatly altered by replacing the internal Al 3+ or Fe 2+ with H + during acidification [5]. On the other hand, the surface areas of acid activated clay particles are greatly increased due to the decomposition of lamellar structure of montmorillonite [3]. During decomposition stage, octahedral aluminum ions are preferentially released from the clay structure, causing the formation of additional Al-OH and Si-OH vibration bonds without much affecting the original mineral structure [6].…”

Physico-chemical variation in bentonite by sulfuric acid activation

“…The application of bentonites in production of selective adsorbents, bleaching earth, catalyst beds, carbonless copy paper and medication depends on the pore structures of montmorillonite [4]. If the pore diameters are smaller than 2 nm, these are called microspores.…”

Estudo de hidrocarbonetos policíclicos aromáticos nos estuários de Santos e São Vicente/SP utilizando diatomito como material adsorvente

“…Desta forma, para a confecção do amostrador cerâmico foi necessário acrescentar um aditivo de conformação. Para este caso foi escolhida a argila bentonita devido as propriedades favoráveis de plasticidade e de adsorção (Babaki et al, 2008). A bentonita foi acrescentada ao diatomito puro na proporção 75% de diatomito: 25% de bentonita fornecendo assim às esferas de diatomito e ao AC, aumento de plasticidade e a resistência mecânica necessária para os períodos de imersão na água de superfície no monitoramento.…”