Investigation of heavy metal adsorption of chromium and zinc ions by natural zeolites as adsorbent

7 Thai natural zeolites with classified name, mordenite (A), kaolinite (B), kaolinite
1Md (C), kaolinite(D), clinoptilolite(E), clinoptilolite(F) and clinoptilolite(G), found in
Songkhla province have been applied to investigate the adsorption of Cr3+ and Zn2+
from aqueous solution on laboratory scale by batch adsorption experiment.
The results show that natural zeolites A, B, C and D are successfully use to adsorb
Cr3+ with the adsorption efficiency of 95.60%, 92.73%, 88.90% and 92.49%, respectively.
The adsorption efficiencies of Zn2+ are 82.38%,
57.84%, 48.19% and 60.75% for natural zeolites A, B, C and D, respectively.
The optimum condition for adsorption of Cr3+ is obtained by suspended each 20.0 g/1
of zeolite A and 30.0 g/1 of zeolites B, C and D in 5.00 ppm Cr3ฑsolution at pH 7.0.
While, suspension of each 30.0 g/1 of zeolites A, B, C and D in 5.00 ppm zinc solution
at pH 7.0 are the optimum condition for adsorption of Zn2+. An hour with systematic
perturbation at the time of 30 minutes for 30 seconds was the optimum adsorption
time for both metal ions. Based on the preliminary chromium and zinc adsorption
studies, the obtained isotherm is consistent to the Langmuir isotherm.
The investigated result indicated that the use of Thai natural zeolite is reasonable
for suitably Cr3+ and Zn2+ adsorption in wastewater treatment with low cost and
environmentally friendly chemical process.