DE was obtained from Lampang province in northern Thailand.
It had particle size (d4,3) of 73 m, specific surface area by BET of
46.8 m2/g and specific gravity of 2.55. Mineralogical compositions
of DE consisted of quartz, montmorillonite, muscovite, kaolinite,
hematite, some semi-crystalline phase and amorphous phases. Laboratory
grade sodium hydroxide (NaOH) and potassium hydroxide
(KOH) and industrial sodium silicate (Na2SiO3) with 32.39% SiO2,
13.44% Na2O and 54.17% H2O were used.