Abstract:
Maredan natural clay has been used as raw material for zeolite synthesis, but the results
are not satisfying because impurities such as metals are still found. It needs a special
treatment that aims to remove these impurities in the clay, namely carrying out the
leaching process with acid. The zeolite synthesis in this study began with the leaching
process of Maredan natural clay with 1 M H2SO4 at 80 oC for 3 hours. The filtered paste
is washed with mineral-free aqua until pH 2 and 4 variations are reached, then calcined
for 3 hours at a temperature of 650 ºC. After calcination, the samples were mixed with 50
mL of 5 M NaOH and stirred at 300 rpm for 3 hours at 80 ºC. After that, the reflux process
was carried out at a temperature of 100ºC for 8 hours. The zeolite solids obtained were
characterized by the XRF method. The results of the analysis revealed that the
composition of Al and Fe levels decreased due to post-leaching pH adjustments 2 and 4.
However, Si levels increased due to the effect of post-leaching pH. The synthesized
zeolite has Si / Al ratios of 1.7 and 2.02. This research shows that increasing the pH
regulation will increase the Si / Al ratio of zeolites produced.
