D. Effect of Agitation Rate on Cu(II) Adsorption
The effect of agitation rate on Cu(II) adsorption was
investigated by adding 0.5 g of adsorbent into 200 ml of copper
solution of 50 mg/L concentration at optimum pH determined
previously. The solution was agitated using water bath shaker
at different stirring rates (150 – 350 rpm) under constant
temperature of 30°C. The remaining concentration of Cu(II)
after adsorption was measured using AAS.
E. Equilibrium Studies of Cu(II) Adsorption
A series of solutions containing different initial
concentrations of Cu(II) ions (in the range of 50 – 350 mg/L)
was prepared and employed for the batch adsorption studies at
30°C to check the applicability of the Langmuir and Freundlich
adsorption isotherms under optimum conditions obtained
previously. The remaining concentration of Cu(II) after
adsorption was measured using AAS and the amount of
adsorption at equilibrium, qe (mg/g) was calculated by: