Adsorpsi ion Cr(III) dan Cr(VI) menggunakan bentonit alam termodifikasi oksida besi

Abstract

Speciation of trivalent and hexavalent chromiums is important to do because both have very different characteristics. Hexavalent chromium is toxic meanwhile trivalent chromium is needed in metabolism. The aim of this study is to modify natural bentonite from Cigudeg, Bogor with sodium and iron oxide to increase its performance as an adsorbent for speciation of Cr (VI) and Cr (III). The result showed that the adsorption capacity of Cr(III) and Cr(VI) using Na-bentonite and modified bentonite were higher than that of natural bentonite. Adsorption capacity of Cr(III) for natural bentonite, Na-bentonite, and modified bentonite were 4.49, 6.08, and 8.17 mg/g adsorbent, meanwhile adsorption capacity of Cr(VI) for natural bentonite, Na-bentonite, and modified bentonite were 4.14, 4.97, and 5.85 mg/g adsorbent, respectively. Adsorption of Cr(III) and Cr(VI) by the three types of bentonite followed the Langmuir isotherm pattern. Characterization using X-ray diffractometer showed shifting, broadening, and changing in the number of peaks in the diffractogram of Na-bentonite and modified bentonite compared to that of natural bentonite. Speciation using adsorption column is constrained by the low flow rate.