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The use of renewable energy sources has become a solution for the global energy and environment issues caused by the depletion of crude oil and emission of greenhouse gases. Biodiesel is categorized as a renewable energy source and is frequently blended with petroleum diesel to decrease the usage of crude oil. During the production of biodiesel via transesterification reaction, glycerol is generated as a by-product which must be separated from the biodiesel through a separation process. This research involved the development and evaluation of a ceramic microfiltration membrane for separating glycerol from biodiesel. A blend of alumina and kaolin was employed as the material for the membrane that was prepared through a slip casting method of the alumina-kaolin suspension, and then followed by a drying and sintering process. To evaluate the separation performance of the membrane, a microfiltration experiment was conducted at various transmembrane pressures of 0.25, 0.5 and 0.75 kg cm-2 using a feed solution of biodiesel that contained glycerol The result of the microfiltration experiment at a pressure of 0.5 kg cm-2 showed that the membrane exhibited a permeate flux of 41 to 70 L m-2 h-1 with a glycerol rejection value of 91%. Increasing the pressure led to an increment in the permeate flux with an average permeability of 81.5 L m-2 h-1 bar-1, while the rejection of glycerol was still high at 91%. Over time, a reduction in the permeate flux was observed due to membrane fouling, resulting in a flux decline ratio of 29-39.2%. However, after flushing the membrane with pure biodiesel the permeate flux increased again with a flux recovery ratio of 74.6 – 83.9%. This result showed that the membrane developed in this work exhibited a good separation and antifouling performance for the biodiesel purification process. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the antioxidant properties of an ethanolic extract of Sargassum polycystum C.A. Agardh. (EES) harvested from Lange coastal area (Aceh Besar). The bioactivity was estimated by conducting 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay followed by phenolic content measurement and infrared (IR) spectroscopy analysis to characterise the possible phytochemicals of the crude extract. The EES demonstrated a stronger free radical scavenging activity expressed in IC50 value of 2.178±0.117 µg/mL compared to other studies in the same species. Furthermore, the phenolic-related component was confirmed based on its phenolic content of 18.572±0.106 mg GAE/g and IR spectroscopy wavenumber of 3367.71 and 1624.06 cm−1 reflecting hydroxyl groups and aromatic rings, respectively. According to the finding, the brown algae from Lange could fairly be considered as a natural resource of antioxidants and phenolic bioactivities. [ABSTRACT FROM AUTHOR]

The preparation and characterization of tubular ceramic membranes aiming to do microfiltration using alumina and kaolin powders as raw materials were carried out. The membranes were obtained by doing slip casting of the suspensions. The suspensions consisted of alumina-kaolin powders, water, and 0.9 wt.% of dolapix CE64 as deflocculant. The variations made during suspension preparation includes the use of different ratios between alumina-kaolin powder and distilled water of 60 wt.% : 40 wt.% and 65 wt.% : 35 wt.%, and also the use of addition of different percentage of starch of 0.5, 1, 2, and 3 wt.% as pore former into the suspension. Upon casting, the manufacture was then followed by sintering process in a furnace, which was also varied into up to 1000°C, 1100°C, and 1200°C. The procedure was then completed by doing subsequent characterizations of the sintered membranes by determining their microstructure using SEM (Scanning Electron Microscopy) and pure water permeability and E. coli bacteria rejection experiment with McFarland turbid solution that were executed in a customized microfiltration module. All of the membrane samples succeeded to have 100% E. coli rejection. However, out of all the membrane samples, membrane with powder to distilled water ratio of 65 wt.% : 35 wt.% with 0.9 wt.% dolapix sintered at 1100°C gave results to the highest water permeate flux. [ABSTRACT FROM AUTHOR]