I. MATERIALSAND METHODS
A. Materials
Copper sulfate (CuSO4) was used for the preparation of
stock standard solutions of Cu(II) in distilled water. For pH
adjustment throughout the experiment, 0.1 M hydrochloric acid
(HCl) and/or 0.1 M sodium hydroxide (NaOH) were used as
necessary. All chemical used in the present study were of
analytical grade from Merck, Germany. Atomic adsorption
spectrometer (AAS Model HGA 850, USA) was used to
measure the Cu(II) concentration.
B. Preparation of Adsorbent
The chicken eggshells were collected from kitchen waste
and washed by deionized water for several times to remove the
dirt particles. The eggshells were then dried overnight in the
oven at 40°C. The dried eggshells were ground into small
particles and stored in an airtight container for future use.
C. Effect of pH on Cu(II) Adsorption
The effect of solution pH on adsorption of Cu(II) was
studied by mixing 0.5 g of adsorbent with 200 ml of copper
solution of 50 mg/L concentration at different pH value (4 – 8)
under 30°C. The pH was adjusted with 0.1 M NaOH or 0.1 M
HCl solutions and measured by pH meter. Agitation was made
at a constant stirring speed of 150 rpm for 180 minutes. The
remaining concentration of Cu(II) after adsorption was