Modified hierarchical zeolite X derived from riceberry rice husk for propionic acid adsorption

Riceberry rice has gained a lot of attention recently in Thailand because of its high nutrition. Riceberry rice husk can be successfully extracted a silica source for zeolite X synthesis as waste utilization by hydrothermal synthesis method. In addition, the hierarchical zeolite was prepared by two post-synthesis modifications, acid modification and recrystallization. The materials were characterized by X-ray fluorescence, X-ray diffraction, nitrogen adsorption/desorption and scanning electron microscopy. Yield of silica extraction from riceberry rice husk was achieved at 23.43% with high purity 81.36 %wt of silica content. After acid modification, 0.5HCl-X was successfully synthesized with high surface area of 543.8 m(2) g(-1) and monodisperse pore size distribution. All synthesized materials were used as the adsorbents for propionic acid adsorption with 222.26 g L-1 initial concentration of propionic acid. The amount of adsorbed propionic acid for 0.5HCl-X was 516 mg g(-1) at equilibrium time 30 min and fitted to the pseudo-second order kinetic model.

Automated summary

Recently, Riceberry rice has gained attention in Thailand due to its high nutritional value. In this study, silica was successfully extracted from Riceberry rice husk through hydrothermal synthesis for the synthesis of zeolite X. Hierarchical zeolite was prepared through acid modification and recrystallization. The extracted silica had high purity, and the acid-modified 0.5HCl-X showed a high surface area and monodisperse pore size distribution. The synthesized materials were used as adsorbents for propionic acid, and the adsorption capacity of 0.5HCl-X reached a maximum of 516 mg g(-1) at an equilibrium time of 30 minutes, following a pseudo-second order kinetic model.