Synthesis and characterization of mordenite zeolite from metakaolin and rice husk ash as a source of aluminium and silicon

Mordenite zeolite is considered a molecular sieve because of its adsorbent material characteristics used in the industry as a gas separator. High Si/Al ratios of this zeolitic material in its crystal lattice provide high thermal stability in the structure. To minimize the production costs, this work synthesized the mordenite zeolite in absence organic template (high costs of production). For this purpose, rice husk ash (silicon source) was used from a thermoelectric plant that uses biomass for power generation under the “Moving Grade Reactor” method and metakaolin (aluminium source) derived from the construction. To obtain the zeolitic material, an alkaline treatment with sodium hydroxide and deionized water was required. Different Si/Al ratios (5, 10, 15, and 20) were used to evaluate the highest efficiency in adsorption capacity. The textural properties of mordenite as a function of specific surface area ranged from 314 to 347 m2/g, with micropore volume 0.198–0.279 cm3/g with average pore diameter ranging from 5.9 to 6.2 A. N2 adsorption/desorption isotherms obtained for mordenite presented type IV hysteresis, characteristic of microporous materials. X-ray diffraction showed crystalline phases of mordenite zeolite, mostly. The FTIR reinforces the success of mordenite synthesis by the vibration bands corresponding to the zeolitic material. TGA revealed water desorption and absence of an organic director. The mean cation-exchange capacity values ranged from 1.10 to 1.78 meq/g indicating a 62% increase of 20-mordenite zeolite compared to 5-mordenite in the zeolitization process. This result is satisfactory and promising for the use of mordenite as adsorbent material.