Ambient-temperature porogen-free method for preparation of silica-based macroporous materials

The presented work focuses on the synthesis of silica-based macroporous aggregates composed of silica nano-particles using a template-free method. To improve the mechanical strength of the prepared fractal-like aggregates, the silica precursor tetraethyl orthosilicate (TEOS) is used during nanoparticle aggregation. The obtained results confirm the possibility to tailor the pore size distribution (PSD) simply by using primary particles of various sizes. The prepared porous materials have a porosity ranging from 60% to 74% with a specific surface area between 10 and 200 m(2)/g and an average pore diameter from 30 to 1300 nm. Functionalization of the aggregate surface was done by replacing part of TEOS with a silica precursor that contained desired functional groups. This was demonstrated by preparing macroporous aggregates with carboxyl, amine and epoxy functional groups. The application of prepared aggregates was demonstrated by immobilization of urease from Canavalia ensiformis resulting in high enzyme activity compare to free enzymes.

Automated summary

The study focuses on synthesizing silica-based macroporous aggregates composed of silica nanoparticles using a template-free method, demonstrating the ability to tailor pore size distribution by varying primary particle size. The prepared aggregates have different pore sizes, porosities, specific surface areas, and functional groups, showing the potential for functionalizing the aggregate surface. The application of the prepared aggregates was demonstrated by immobilizing urease from Canavalia ensiformis, resulting in higher enzyme activity compared to free enzymes.