Oil palm (Elaeis guineensis Jacq.) fronds (OPF) are the most abundant oil palm solid wastes that are generated during oil palm agriculture and harvest. Palm oil and some other palm wastes have been reported to contain high concentrations of carotenoids with vital bioactive properties. However, the extraction and quantification of carotenoids from OPF have not been reported. In this study, ultrasonic‐assisted extraction, HPLC–FLD for quantification, and response surface methodology (RSM) for optimization of β‐carotene, lutein, and zeaxanthin from OPF extracts were investigated. The effects of extraction temperature (X 1: 30–70°C), extraction time (X 2: 10–50 min), and solvent–sample ratio (X 3: 10–50 mL/g) on the recovery of β‐carotene (Y 1), lutein (Y 2), and zeaxanthin (Y 3) were investigated using three‐level Box–Behnken design (BBD) experiment. At a desirability of 1, the optimum extraction conditions for β‐carotene (30.14°C, 37.11 min, and 23.18 mL/g), lutein (30.00°C, 39.09 min, and 19.24 mL/g), and zeaxanthin (30.09°C, 36.76 min, and 22.38 mL/g) yielded carotenoid concentrations of 17.95 μg/g dry weight (DW), 261.99 μg/g DW, and 29.99 μg/g DW, respectively.

The removal of sulfur dioxide (SO 2 ) from simulated flue gas was investigated in a laboratory-scale stainless steel fixed-bed reactor using sorbents prepared from various siliceous materials, i.e., coal fly ash (CFA), oil palm ash (OPA) and rice husk ash (RHA) mixed with lime (CaO) by means of the water hydration method. Experiments were carried out with a flue gas flow rate of 150 mL/min, reaction temperature of 100°C, and SO 2 concentration of 1000 ppm. It was found that sorbents prepared from RHA have high BET surface areas and high SO 2 sorption capacities, based on breakthrough curve analysis. In addition, the SO 2 breakthrough curves were also described in terms of a simple first-order deactivation model containing only two rate constants, one of which, k s , describes the surface reaction rate constant while the other, k d , describes the deactivation rate constant. The values of k s and k d obtained from the deactivation kinetics model were in good agreement with the experimental breakthrough curves and were also compared with those available in the literature.

Biodiesel is currently considered as the most promising substitute for diesel fuel because of its similar properties to diesel. This study presents the use of the supercritical methanol method in the production of biodiesel from Croton megalocarpus oil. The reaction parameters such as methanol-to-oil ratio, reaction temperature and reaction time were varied to obtain the optimal reaction conditions by design of experiment, specifically, response surface methodology based on threevariable central composite design with a = 2. It has been shown that it is possible to achieve methyl ester yields as high as 74.91 % with reaction conditions such as 50:1 methanol-to-oil molar ratio, 330°C reaction temperature and a reaction period of 20 min. However, Croton-based biodiesel did not sustain higher temperatures due to decomposition of polyunsaturated methyl linoleate, which is dominant in biodiesel. Lower yields were observed when higher temperatures were used during the optimization process. The supercritical methanol method showed competitive biodiesel yields when compared with catalytic methods.

This study reported a simplified method to prepare sulfated zirconia loaded on alumina catalyst for transesterification of Jatropha Curcas L. oil with methanol to biodiesel or fatty acid methyl esters. The catalyst was found to have high catalytic activity. X-ray diffraction and Fourier transform infrared spectroscopy analysis showed that the catalyst has the basic characteristic of an acidic catalyst. The catalyst preparation conditions were optimized using design of experiment, specifically response surface methodology and an optimum fatty acid methyl ester yield (91.0 wt%) was obtained using a catalyst prepared with calcination temperature and duration at 329 ı C and 4.7 h, respectively.

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