ADSORPSI ION Pb2+ DAN SO4 2- PADA BENTONIT TERMODIFIKASI CETILTRIMETILAMMONIUM

Adsorption of Pb 2+ and SO4 2- ions by N-cetyl-N,N,N-trimethylammonium (CTA + ) cationic surfactant modified bentonite has been studied. The research was started by washing bentonite of Thailand using 1.5 M sulfuric acid followed by modification using CTA + surfactant with concentration as much as twice of cation exchange capacity (CEC). The CTA + modified bentonite was then used for adsorption of Pb 2+ and SO4 2- ions. The bentonite samples were characterized by FTIR spectrometry and X-ray diffraction methods, whereas the analysis of Pb 2+ cation was measured by AAS and the analysis of SO4 2- anion was measured by UV-Vis spectrophotometer. Results showed that major mineral component of bentonite was montmorillonite and acid activation process caused dealumination. The adsorption process of Pb 2+ and SO4 2- on CTA-bentonite followed the Langmuir adsorption isotherm. The value of adsorption capacity was 7.42 x 10 -5 mol/g for SO4 2- and 1.38 x 10 -5 mol/g for Pb 2+ . Meanwhile, the adsorption energy was 23.90 kJ/mol for SO 4 2- and 33.28 kJ/mol for Pb 2+ . The adsorption capability of Pb 2+ on natural bentonite > activated bentonite > CTA bentonite and the adsorption capability of SO4 2- on CTA-bentonite > activated bentonite > natural bentonite