Molecular sieve material from liquid–crystal-display waste glass and silicon carbide sludge via hydrothermal process with alkali fusion pretreatment

Abstract

The goal of this paper was to synthesize eco-humidity-conditioned Al-MCM-41 mesoporous molecular sieves (CHCMs) from liquid–crystal-display waste glass (LCDWG) and silicon carbide sludge (SiCS) via an alkali fusion process. LCDWG and SiCS are primarily composed of SiO2 and Al2O3. The characterization of CHCM materials under different synthesis conditions and their humidity regulation effects were compared. The results showed that the CHCM materials exhibit type-IV isotherms and clearly defined capillary phenomena and were composed of hexagonal Al-MCM-41, which is a mesoporous material. When the optimal reaction temperature was 120 °C, and the liquid/solid ratio (L/S) was 15, the highest equilibrium moisture content of the synthesized CHCM sample was 66.84 m3/m3. In addition, the large surface area (1120 m2/g), pore size (5.2 nm), pore volume (0.93 cm3/g) and wall thickness (1.44 nm) of the samples improved the moisture absorption capacity of the equilibrium moisture content. The equilibrium moisture content of the CHCM samples was higher than those of rape straw concrete and hemp concrete (9.8–17.8 m3/m3) and that of a diatomite/ground calcium carbonate composite material (11.7 m3/m3). This study focused on the unique properties of synthesized CHCM samples and the utilization of LCDWG and SiCS to produce samples and thereby solve the disposal problem associated with LCDWG and SiCS. Therefore, CHCMs can be used in several applications, particularly as CHCM materials in construction.