Facile preparation and hardened properties of porous geopolymer-supported zeolite based on swelled bentonite

Porous geopolymer-supported zeolites (PGZs) were successfully prepared by crystallizing bentonite-amended porous geopolymers, to study their synthesis, pore-forming mechanism, pore structure, and hardened properties. The results revealed that geopolymer gel and montmorillonite layers in porous geopolymers could subdivide and refine capillary voids, thereby forming submicron pores. Further, hydrothermal curing resulted in the formation of a zeolite-based matrix. The pores and the zeolite-based matrix caused a considerable reduction in the thermal conductivity of the PGZ. The PGZ pore volume rose steadily from 0.47 cc/g to 0.80 ccig with increasing bentonite slurry from 40% to 60%. The contents of the bentonite slurry were added to the geopolymer paste and then crystalized for 24 h at 90 degrees C, yielding PGZs with a thermal conductivity, compressive strength, and dry density of 0.121-0.167 W/m K, 2.3-8.7 MPa, and 774-930 kg/m(3), respectively. (C) 2019 Elsevier Ltd. All rights reserved.