Hierarchical zeolite based on multiporous zeolite A and bacterial cellulose: An efficient adsorbent of Pb2+

A multiporous zeolite A (Ab) was obtained by the addition of the organosilane molecule dimethyl octadecyl [3(trimethoxysilyl)propyl]ammonium chloride (TPOAC) in the synthesis gel and successfully dispersed in bacterial cellulose forming aerogels for Pb2+ adsorption. Several characterization techniques such as powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N-2 adsorption-desorption were employed to investigate physical, chemical, and textural properties of the samples. The resulting material is also compared to the conventional microporous zeolite A and shows a positive interaction between zeolite crystals and cellulose nanofibrils, specially when the mesopores are present in the crystal. Improvements are observed for the multiporous samples in both adsorption and ionic exchange processes. The selectivity for Pb2+ in the presence of Cd2+ is enhanced as a result of improved intraparticle diffusion where there is the insertion of mesopores to the structures. From the kinetic models, the pseudo-second order model fits better to the experimental data suggesting chemisorption as the governing process in adsorption and the mesopores seem to have a remarkable role on it. These multiporous materials facilitate the access of Pb2+ to the zeolite inner pores and therefore present high potential to be used for both Pb2+ adsorptive and analytical devices.

Automated summary

Multi-porous zeolite A was successfully synthesized and dispersed in bacterial cellulose aerogels for Pb2+ adsorption. Characterization techniques revealed positive interaction between zeolite crystals and cellulose nanofibrils, with improvements in adsorption and selectivity when mesopores are present in the crystal. This study highlights the potential of these multi-porous materials for Pb2+ adsorption and analytical applications.