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

MAISARI UTAMI, Dr. Sutarno, M.Si.

2014 | Skripsi | KIMIA

Telah dilakukan penelitian tentang adsorpsi ion Pb 2+ dan SO4 2- menggunakan bentonit termodifikasi surfaktan kationik N-cetil-N,N,N trimetilammonium (CTA + ). Penelitian ini diawali dengan pencucian bentonit Thailand menggunakan asam sulfat 1,5 M kemudian dimodifikasi menggunakan CTA + dengan konsentrasi sebesar dua kali kapasitas tukar kation (KTK). Bentonit termodifikasi CTA + kemudian digunakan untuk adsorpsi terhadap ion Pb 2+ dan SO4 2- . Karakterisasi material dilakukan dengan metode spektrometri FTIR dan difraksi sinar-X, sedangkan analisis kation Pb 2+ dikaji dengan AAS dan analisis anion SO4 2- dikaji dengan spektrofotometer UV-Vis. Hasil penelitian menunjukkan bahwa komponen mineral utama bentonit adalah montmorillonit dan proses aktivasi asam menyebabkan dealuminasi. Proses adsorpsi CTA bentonit terhadap Pb 2+ dan SO4 2- mengikuti isoterm adsorpsi Langmuir. Nilai kapasitas adsorpsi adalah sebesar 7,42 x 10 -5 mol/g untuk SO4 2- dan 1,38 x 10 -5 mol/g untuk Pb 2+ . Sedangkan energi adsorpsi adalah sebesar 23,90 kJ/mol untuk SO4 2- dan 33,28 kJ/mol untuk Pb 2+ . Kemampuan adsorpsi Pb 2+ pada bentonit alam > bentonit teraktivasi > CTA-bentonit dan kemampuan adsorpsi SO4 2- pada CTA-bentonit > bentonit teraktivasi > bentonit alam.

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.

Kata Kunci : modifikasi bentonit, adsorpsi, Pb 2+ dan SO4 2