Impregnasi Fe/Cu pada Material Mesopori Silika Template Metil Ester Risinoleat sebagai Adsorben-Reduktor Kromium (VI)

Abstract

Chromium is one of the heavy metals that is widely used in industrial activities. Chromium metal (especially hexavalent chromium) has high toxicity. Nowadays, adsorption-reduction technique is the most efficient treatment in the removal of chromium pollution from water. Mesoporous silica templated by methyl ester ricinoleate has a large surface area. Nano Zero Valent Iron (nZVI) has high reactivity with chromium (VI) as it can donate its electrons to reduce Cr6+ to less toxic Cr3+ then precipitate and carry chromium out from solution. The electron transfer process by nZVI is assisted by the presence of catalytic metals such as copper. Based on the above explanation, researcher interested to loading Fe/Cu metals on mesoporous silica template ricinoleate methyl ester to adsorpt and reduct chromium metal from a solution. The stages of this research were carried out by synthesizing templates from castor oil, synthesizing mesoporous silica, impregnating Fe/Cu into silica pores, and adsorpt chromium (VI) from solutions by variations of concentration are 10, 20, and 30 ppm. GC-MS analysis showed the conversion of ricinoleic acid from castor oil was 89.58% so that it can be used as a template. BET results on mesoporous silica prove that the pores of silica are in the meso range (6.85886 nm) with a surface area is 260.15 m2/g. FT-IR analysis on mesoporous silica showed the presence of silanol groups at wave numbers 3448 cm-1, 1620 cm-1, and 964 cm-1; siloxane groups at wave numbers 1110 cm-1, 802 cm-1, and 462 cm-1. New peaks appear on mesoporous silica after impregnation at 1624 cm-1 and 1335 cm-1 which showed the adsorption bands of nZVI, while Cr-O adsorption bands appears at 493 cm-1 after the mesopores adsorpt chromium. XRD analysis showed the high crystallinity of the adsorbent and the peak at 2θ 44.23° indicated the cubic structure of nZVI. AAS analysis showed that the adsorption of chromium by Fe/Cu-MS-TMR reached 82.78%, making it better than adsorption by mesoporous silica without Fe/Cu.