BENTONIT TERPILAR OKSIDA LOGAM Al/Fe SEBAGAI ADSORBEN CAMPURAN ZAT WARNA CONGO RED DAN DIRECT GREEN

The pillarisation process of Al/Fe metal oxide compound in bentonite has been conducted with metal oxide ratios 1 : 2 and 2 : 1. The product of bentonite pillared by Al/Fe metal oxide were characterized by using FT-IR spectrophotometer and XRD analysis. The characterization of using the FT-IR spectrophotometer does not shown optimum pillarisation processes for any metal oxide ratios, while the XRD analysis showed optimum pillarisation processes on 17.1 Ȧ with 5.18 o angular diffraction peak (2θ) at 2 : 1 metal oxide ratio. However, it doesn’t show 3-6 o angular diffraction peak (2θ) as the special characterization of bentonite in 1 : 2 metal oxide ratio. Thus, this optimal pillarisation product was used as adsorbent of congo red, direct green and mixed dyestuffs. The adsorption rate (k) of these processes showed 0.00109 minute-1 for congo red and 0.0012 minute-1 for direct green. The highest adsorption capacity (qe) result happened on 70 oC showed 57.34 mol/g and 72.06 mol/g for direct green, respectively the highest adsorption energy (E) was found on 70 oC were 3.23 kJ/mol for congo red and 4.14 kJ/mol for direct green. The entalphy (ΔH) and entropy (ΔS) values decreased as the increasing of congo red, direct green, and mixed dyestuffs dye concentration.