Impact of the specific surface area and active phase on performance of ball-milled CaO-derived catalysts on used cooking oil transesterification
Ilmi Fadhilah Rizki, Frisda Rimbun Panjaitan*, Bagus Giri Yudanto, Brahmani Dewa Bajra, Manda Edy Mulyono, Mulki Salendra Kusumah

Indonesia Oil Palm Research Institute


*frisdapanjaitan[at]iopri.org

Abstract

A novel CaO nanocatalysts was prepared by ball-milling method and applied to fatty acid methyl esters synthesis by used cooking oil transesterification. Two types of solid base catalysts were obtained: CaO and Ca-glyceroxide active phases with moderate specific surface area. In this work, we studied: (i) prepared solid base catalysts with moderate surface area and CaO and Ca-glyceroxide active phases- (ii) compared used cooking oil transesterification using CaO and Ca-glyceroxide active phase with moderate specific surface area and NaOH catalyst at 40oC and 65oC, and (iii) investigated what is the true catalytic active phase because CaO catalyst drastically change its structure during transesterification reaction. Solid base nanocatalysts obtained were characterized by XRD, SEM, FTIR, and BET. Large surface area of catalyst was effective in reducing mass transfer limitation in the beginning of reaction that increasing the initial rate of transesterification. We also found that the real active phase that catalyzed the reaction is Ca-glyceroxide, therefore transformation CaO into Ca-glyceroxide became critical point in CaO catalyzed transesterification. The catalytic tests with low acidic used cooking oil showed that fatty acid methyl ester can be produced over ball-milled CaO-derived catalysts without significant deterioration of the catalytic performances.

Keywords: specific surface area- active phase- ball-milling- fatty acid methyl esters

Topic: Renewable energy and biorefinery