Pembuatan dan Karakterisasi Katalis CaO/Zeolit Alam

Abstract

ABSTRAK
CaO telah banyak digunakan sebagai katalis heterogen dalam reaksi transesterifikasi. Dalam penelitian ini, katalis CaO/zeolit alam telah berhasil disintesis menggunakan metode impregnasi basah. Campuran zeolit alam dan CaO diaduk di dalam refluks selama 90 oC selama 3 jam. Variasi rasio massa CaO/zeolit alam yaitu 5%, 10%, dan 15% yang selanjutnya diberi label CaO/NZ5%, CaO/NZ10%, and CaO/NZ15%, secara berturut-turut. Analisis menggunakan FTIR menunjukkan bahwa gugus-gugus fungsi zeolit alam tidak mengalami perubahan ketika pengembanan CaO dilakukan. Hasil ini didukung oleh hasil pengukuran menggunakan XRD yang menunjukkan kemunculan puncak-puncak difraksi dari mineral-mineral zeolit alam. Luas permukaan katalis yang diukur manggunakan N2 sorption analyzer menunjukkan bahwa semakin banyak jumlah CaO yang diembankan pada zeolit alam, semakin kecil luas permukaan katalis dari 15,201 m2/g sampai 12,928 m2/g. hasil tersebut mengindikasikan bahwa CaO menyusutkan ukuran pori zeolit, sehingga luas permukaan zeolit menurun. Analisis menggunakan metode titrasi asam basa menunjukkan bahwa kebasaan katalis meningkat seiring dengan meningkatnya jumlah CaO yang diembankan pada zeolit alam.
Kata kunci : Katalis, CaO, zeolit alam, impregnasi basah.
ABSTRACT
CaO has been well known as a great heterogenous catalyst in the transesterification reaction to produce biodiesel. In the present study, synthesis of CaO/natural zeolite catalyst has been succesfully conducted using wet impregnation method. Impregnation was done by stirring the mixture of natural zeolite and CaO in reflux apparatus at 90 oC for 3 hours. The amount of CaO impregnated into natural zeolite were 5%wt, 10%wt, and 15%wt. These catalysts were then labeled as CaO/NZ5%, CaO/NZ10%, and CaO/NZ15%, respectively. Analysis using FTIR showed no change in functional groups when CaO was impregnated into the pores of the zeolite. This result was supported by the result of the XRD pattern which shows the appearance of natural zeolite diffraction peaks. Surface area measurement using N2 sorption analyzer showed the greater the amount of CaO impregnated into zeolite, the smaller the surface area of the catalyst from 15.201 m2/g to 12.928 m2/g. This result indicates that the CaO shrinked the pore size of zeolite, thus, the surface area of natural zeolite decreased. Acid-base titration result showed that the basicity of catalyst increased as the amount of CaO impregnated into natural zeolite increased.
Keywords: Catalyst, CaO, natural zeolite, wet impregnation