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Masoud Rahimi,Elham Mohamadian,Soheil Dadari,Mohammad Moein Arbab,Naser Karimi 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.4
Microalgae are considered the biological drug factories of the future. To benefit from these microfactories, the intracellular metabolite of algae should be extracted. One of the most economically competitive methods is the ultrasound technique. This study was concerned with ultrasound-assisted extractions of useful substances from microalgae by comparing direct and indirect irradiation methods with respect to the extraction rate and yields. It is most likely that the direct and indirect irradiations had different irradiation powers. The systems were exposed to ultrasound wave (1.7 MHz) for 240min. For each system, the changes of optical density, concentration and biovolume of Chlorella were estimated. In addition, the concentration of extracted chlorophylls (a, b and a+b), carotenoid and lipid were measured. The factors were studied after 30, 60, 120, 180 and 240 min of exposure to ultrasound irradiation. Both direct and indirect irradiation systems produced cavitation in the cell membrane, and they reduced the concentration and biovolume of the Chlorella cells. The amount of lipids and chlorophylls was greater in the direct irradiation as compared to the indirect one, and it caused more cell disruption. However, the extraction of the carotenoid was less effective because direct irradiation produced more transmitted power of ultrasound, resulting in degradation of carotenoid. The results and analysis presented in this research showed that selection of the best method of irradiation is an important step, and it depends on the biomaterials to be extracted.
Masoud Rahimi,Soheil Dadari,Sirus Zeinaddini,Elham Mohamadian 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.5
Polyethersulfone (PES) nanofiltration (NF) membranes were prepared by blending of synthesized hydrophilic adipate ferroxane nanoparticles (AFNPs) as a novel multifunctional nanofiller via the phase inversion method. The water contact angle measurement indicated the higher hydrophilicity of the NF membranes. The water flux of the membranes improved significantly after the addition of AFNPs, from 10.4 to 32.2 kg/m2h. Antifouling characteristics of AFNPs/PES membranes were improved by increased hydrophilicity and decreased membrane surface roughness. The 0.6 wt% AFNPs/PES membrane exhibited the highest FRR (96%) and the lowest irreversible fouling resistance (6%). The nanofiltration performance of the prepared membranes was evaluated by dye removal and salt retention. The results proved the high dye removal capability of modified membranes (98% rejection) compared with the unfilled PES membrane (89% rejection). The salt retention sequence for membrane with 0.2 wt% of nanoparticles was Na2SO4 (70%)>MgSO4 (60%)>NaCl (18%).