Bifunctional heterogeneous catalysts have a great potential to overcome the shortcomings of homogeneous and enzymatic catalysts and simplify the biodiesel production processes using low-grade, high-free-fatty-acid feedstock. In this study, we developed ZrO2-based bifunctional heterogeneous catalysts for simultaneous esterification and transesterification of microalgae to biodiesel. To avoid the disadvantage of the low surface area of ZrO2, the catalysts were prepared via a surfactant-assisted sol-gel method, followed by hydrothermal treatments. The response surface methodology central composite design was employed to investigate various factors, like the surfactant/Zr molar ratio, pH, aging time, and temperature on the ZrO2 surface area. The data were statistically analyzed to predict the optimal combination of factors, and further experiments were conducted for verification. Bi2O3 was supported on ZrO2 via the incipient wetness impregnation method. The catalysts were characterized by a variety of techniques, which disclosed that the surfactant-assisted ZrO2 nanoparticles possess higher surface area, better acid–base properties, and well-formed pore structures than bare ZrO2. The highest yield of fatty acid methyl esters (73.21%) was achieved using Bi2O3/ZrO2(CTAB), and the catalytic activity of the developed catalysts was linearly correlated with the total densities of the acidic and basic sites. The mechanism of the simultaneous reactions was also discussed.
The unexpected closure of educational institutions as a result of the emergence of COVID-19 prompted the authorities to suggest adopting alternatives to traditional learning methods. E-learning is an innovative approach for delivering electronically mediated, well-designed, learner-centred interactive learning environments by utilizing internet and digital technologies with respect to instructional design principles. This paper presents the implementation and prototyping of an innovative web-based e-learning platform for chemistry course known as Al-Chemy. Al-Chemy was developed for foundation students at Tahmidi Centre, Universiti Sains Islam Malaysia. The rapid application development (RAD) methods have been used in developing Al-Chemy through website wix.com. Al-Chemy was structured with interactive notes, animation, virtual experiment, quizzes, and games. The combination of these activities helps students in learning basic and advanced concepts of chemistry.
A novel approach of dual lipases system was successfully carried out in improving the synthesis of ferulate esters between ethyl ferulate and olive oil. Combination of Novozym 435 and Lipozyme RMIM were used as biocatalyst to improve the reaction performance. Different reaction parameters (ratio of lipases, reaction time, lipase dosage, substrate molar ratio and reaction temperature) were analyzed systematically. A high conversion of ferulate esters (85%) was obtained after 12 hrs of reaction time at optimal conditions of 1:9 w/w (Novozym 435/Lipozyme RMIM), 80 mg of lipase and 1:4 ethyl ferulate:olive oil at 60 oC.
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