. RESEARCH METHODOLOGY
Zeolite preparation procedures
Natural zeolite to be used grinded and then sifted
according to the size specified.
Weigh 100 grams of
zeolite then wash it using distilled water, insert the
zeolite into NaCl 1N solution with a ratio of 1 gram of
zeolite in 10 ml solution stirred for 24 hours.
stirring and then filtered and washed with distilled
water to neutral (pH of secondhand washed water
measured with pH paper).
Strain again to be able to
separate the filtrate to residue. Dry the residue in an
oven at temperatures of 110-1200C for 3 hours and the
From Figure 1 shows that the adsorption of
zeolite for the Ca2+ is very depend on processing time,
where the longer time the process result the absorption
of Ca2+ metal will be greater and this is because the
process of absorption of the Ca2+ metal is the physical
processes that are running slowly (takes time), the
longer absorption time mean of the absorbed metals
will be greater or metal left in the seawater will be
smaller but at a certain time a decrease in Ca2+ ion
concentration of this is due to the weakening of zeolite
The best condition was obtained at 75
minutes of stirring time with zeolite size of 100 meshes
with Ca2+ ion concentration of 909.25 mg / l.
From Figure 2 shows that the adsorption of
zeolite for the Ca2+ metal depend on the particle size of
Where the particle size of zeolite is smaller, the
active power of zeolite has greater absorb Ca2+ metal in
seawater so that less and less.
In the zeolite particle
size of 20 meshes, the Ca2+ concentration and
decreased only slightly and this is because the small
surface area of zeolite, while for the zeolite particle
size 100 meshes zeolite the higher absorption due to
the large surface area.
The best condition was obtained
at 75 minutes of stirring time with zeolite size of 100
meshes with Ca2+ ion concentration of 909.25 mg / l.
Based on research that has been done, it can be
1. The bigger the surface area of zeolite particle
the greater the adsorption capacity of Ca2+
2. The longer the stirring time, the greater
absorption of Ca2+ ions occurs so that the
higher the absorbed until it reaches its
saturation point is at 75 minutes.
3. The relatively good conditions of adsorption
for Ca2+ ions occurs on the zeolite particle size
of 100 meshes with a weight of 100 grams of
zeolite, the stirring speed of 200 rpm and
stirring time for 75 minutes the final Ca2+
concentration of 909.25 mg / l.
4. Zeolite can be used as an adsorbent to reduce
the metal content of Ca2+ in seawater but it has
not been able to meet the standardization of
quality standards as clean water for hardness
as CaCO3 with a concentration of 500 mg / l.