Controlling the Size and Porosity of Sodalite Nanoparticles from Indonesian Kaolin for Pb 2+ Removal.

Mesoporous sodalite nanoparticles were directly synthesized from Indonesian kaolin with the addition of CTABr as a mesopore template. The studies highlighted the importance of aging time (3-12 h) and temperature (50-80 °C) on increasing surface area and mesoporosity of sodalite. Indonesian kaolin was used without pre-treatment and transformed to sodalite following the initial molar composition of 10 Na 2 O: 2 SiO 2 : Al 2 O 3 : 128 H 2 O. Characterization data revealed the formation of high surface area sodalite with mesoporosity at increasing aging temperatures and times. The presence of CTABr as templates produced sodalites nanoparticles with smaller aggregates than the non-template sodalite. The sodalite sample obtained at 80 °C of crystallization temperature for 9 h (S80H9) displayed the highest mesopore volume (0.07612 cm 3 /g) and the highest adsorption capacity of Pb 2+ (212.24 mg/g). Pb 2+ was suggested to adsorb via ion exchange with the Na + counter cation and physical adsorption.