R. Farzandi; H. Nayebzadeh; M. Hokmabadi; N. Saghatoleslami
Abstract
The effect of cultivation culture on the biodiesel yield produced from in-situ transesterification of Chlorella vulgaris microalgae was assessed. Firstly, the algae were cultivated in Moh202, sterilized wastewater (SW), unsterilized wastewater (USW) mediums. It was found that around ten days were suitable ...
Read More
The effect of cultivation culture on the biodiesel yield produced from in-situ transesterification of Chlorella vulgaris microalgae was assessed. Firstly, the algae were cultivated in Moh202, sterilized wastewater (SW), unsterilized wastewater (USW) mediums. It was found that around ten days were suitable to receive maximized growth of microalgae; while, maximum and minimum growth was detected in Moh202 and SW media. Before assessment, the effect of cultivation medium on the biodiesel content, the transesterification reaction conditions such as catalyst (NaOH) concentration, reaction time and amount of methanol were investigated by algae cultivated in Moh202 medium via fractional factorial design as statistical methodology. In the range of the study, catalyst concentration and reaction time were the most important effective parameters on the biodiesel yield. Moreover, the interaction between reaction time with catalyst concentration and amount of methanol was also important. In short reaction time and its interaction with catalyst concentration had positive effect, while catalyst concentration, amount of methanol and interaction of reaction time and amount of methanol had negative impact on the biodiesel yield. The yields of the algae cultivated in Moh202, sterilized and unsterilized wastewater media at the optimum conditions of 1 wt.% of catalyst, 9 mL methanol/g biomass and reaction time of 4 hours were 95.5%, 83.9% and 75.5%, respectively. Although the difference between biodiesel yields of Chlorella vulgaris Microalgae cultivated in the wastewater medium compared to sterilized wastewater medium was observed, wastewater can be used as a medium for cultivation of algae for biodiesel production to reduce the biodiesel production costs.
S. Hena; N. Fatihah; H. Awang
Abstract
In this study a simple and rapid harvesting method using electro conductive polymer coated saw dust has been presented as a new coagulant for separating Chlorella vulgaris from a diluted suspension. Polypyrrole (PPy) coated saw dust as a novel coagulant was prepared via in-situ polymerization of pyrrole ...
Read More
In this study a simple and rapid harvesting method using electro conductive polymer coated saw dust has been presented as a new coagulant for separating Chlorella vulgaris from a diluted suspension. Polypyrrole (PPy) coated saw dust as a novel coagulant was prepared via in-situ polymerization of pyrrole (Py) monomer using FeCl3 oxidant in aqueous medium in which saw dust particles were suspended. The zeta potential of coagulant and C. vulgaris and X-ray photoelectron spectroscopic (XPS) analysis of coagulant were characterized. PPy maintain predominantly positive charge over a wide pH range (2-10) with an isoelectric point 10.4 while, C. vulgaris maintained negative surface charge from pH 5 and onward with isoelectric point 3.8. The microalgae showed the highest separation efficiency at pH 10. The maximal recovery efficiency reached more than 90% for microalgae at a stirring speed of 120 rpm within 7 min. The maximal adsorption capacity of C. vulgaris was 28.8 mg dry biomass/mg-saw dust coated PPy. The concentration factor obtained is higher than 32 which save energy and time associated with microalgal harvesting and allows a reduction in the equipment size necessary for biomass dewatering and improves the feasibility of using these microorganisms in biofuel or wastewater processes.
