Triggering the aqueous interparticle association of gamma-Al2O3 hierarchical assemblies using divalent cations and cellulose nanofibers

Understanding aqueous dispersion, rheological properties and colloidal stabilisation mechanisms of hierarchically assembled ceramic powders is important for progress in the fields of catalysis, separation and/or adsorption. The present study was designed to evaluate the rheological and sedimentation behaviour of highly loaded aqueous suspensions (up to phi(A) = 0.126) containing AlN-powder-hydrolysis-derived, micron-sized, mesoporous, gamma alumina (MA) particulates with a high surface area (similar to 180 m(2)/g) dispersed with sodium polyacrylate (NaPAA). The as-prepared suspensions were prone to sedimentation and segregation. However, when divalent cations (Mg2+, Ca2+) or cellulose nanofibers were added, the formation of interparticle association networks in the aqueous suspensions containing MA particles was triggered, facilitating their long-term resistance to sedimentation lasting more than 12 weeks.

Automated summary

This study evaluated the rheological and sedimentation behavior of aqueous suspensions containing micron-sized, mesoporous, gamma alumina (MA) particles with high surface area dispersed with sodium polyacrylate. It was found that the addition of divalent cations or cellulose nanofibers triggered the formation of interparticle association networks, leading to long-term resistance to sedimentation lasting more than 12 weeks.