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    Effect of culture age and initial inoculum size on lipid accumulation and productivity in a hybrid cultivation system of Chlorella vulgaris

    , Article Process Safety and Environmental Protection ; Volume 104 , 2016 , Pages 111-122 ; 09575820 (ISSN) Heidari, M ; Kariminia, H. R ; Shayegan, J ; Sharif University of Technology
    Institution of Chemical Engineers 
    Chlorella vulgaris was cultivated in a hybrid (two-stage) system. The effect of the transferring time from nutrient-replete phase with a low light intensity (photobioreactor) to the nutrient deprivation phase (open pond) with a higher light intensity, as well as the effect of initial cell concentration in the deprivation phase, on the growth rate and lipid content of the microalgae was investigated. The microalgae were transferred to the nutrient deprived medium at different intervals with various initial cell concentrations. Transferring the cultivated medium of the 4th day with the initial cell concentration of 66 mg L−1 into the deprivation phase resulted in a highest lipid productivity... 

    Comparison of different trophic cultivations in microalgal membrane bioreactor containing N-riched wastewater for simultaneous nutrient removal and biomass production

    , Article Process Biochemistry ; Volume 51, Issue 10 , 2016 , Pages 1568-1575 ; 13595113 (ISSN) Babaei, A ; Mehrnia, M. R ; Shayegan, J ; Sarrafzadeh, M. H ; Sharif University of Technology
    Elsevier Ltd  2016
    In this study, a submerged membrane was installed in a bioreactor to treat N-riched wastewater and obtain high biomass productivity. Chlorella vulgaris was cultivated under mixotrophic, heterotrophic, and photoautotrophic conditions in different kinds of nitrogen sources (nitrate and ammonium) to compare the microalgae growth and nutrient removal in a membrane bioreactor. Further, the respirometric and photosynthetic activities of microalgae were investigated to evaluate the viability of microalgae in different conditions. The highest biomass productivity was obtained under mixotrophic cultivation in ammonium source (0.230 ± 0.009 gr/L d). Moreover, with this type of cultivation and nitrogen... 

    Removal of Cr(VI) by modified brown algae Sargassum bevanom from aqueous solution and industrial wastewater

    , Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 44, Issue 6 , 2013 , Pages 977-989 ; 18761070 (ISSN) Javadian, H ; Ahmadi, M ; Ghiasvand, M ; Kahrizi, S ; Katal, R ; Sharif University of Technology
    The aim of this research work is to investigate sorption characteristic of acid treated brown algae Sargassum bevanom (acid treated S. bevanom) for the removal of Cr(VI) ions from aqueous solutions. The acid-treated alga was prepared by transferring the S. bevanom into 0.5. M HCl and then stirring the mixture at 300. rpm for 6. h at room temperature. The sorption of Cr(VI) ions by batch method is carried out. The optimum conditions of biosorption were found to be: a biomass dose of 0.7. g in 100. ml of Cr(VI), contact time of 110. min and pH 3, respectively. In optimum condition, removal efficiency was 89.64%. It was found that temperature has a positive effect on the removal efficiency.... 

    Harmful algal blooms (red tide): a review of causes, impacts and approaches to monitoring and prediction

    , Article International Journal of Environmental Science and Technology ; Volume 16, Issue 3 , 2019 , Pages 1789-1806 ; 17351472 (ISSN) Zohdi, E ; Abbaspour, M ; Sharif University of Technology
    Center for Environmental and Energy Research and Studies  2019
    Red tide, an impermanent natural phenomenon including harmful algal blooms, causes changing the color of the sea generally to red or almost brown, and has a serious impact on environment along the coast and aquatic ecosystem. Due to recent extensive steady harmful algal blooms events that cause adverse impacts on human healthsome, aquaculture and tourism industry, and the entire economy of the coastal region, the need of society for realizing these phenomena is much greater than the past. In the recent decades, consideration of algal blooms and determination of bloom-former species and fundamental researches about dynamics of blooms are increased worldwide. Development in technology has... 

    Control of Eutrophication in Anzali Wetland by Artificial Floating Islands

    , M.Sc. Thesis Sharif University of Technology Shahrouz Ebrahimi, Pouneh (Author) ; Abrishamchi, Ahmad (Supervisor)
    Anzali wetland, in the Caspian Sea, northern Iranian province of Gilan, ranges from fresh near the tributary streams to brackish near the mouth into the harbor and the sea. Anzali wetland has faced with the serious levels of eutrophication because on the other hand, the lagoon has decreased in size during current century, to less than a quarter of its former extent and on the other hand, this wetland is faced with entering a huge amount of nutrient elements due to human activities in its watershed. Discharge of industrial wastewater, animal wastes, timber harvesting and the most important entering, rice farms irrigated wastewater are of the considerable causes of eutrophication in wetland.... 

    Evaluation Effects of Mo, Bi &Sn Biocides On the Anti-Fouling Paints

    , M.Sc. Thesis Sharif University of Technology Bayat, Amin (Author) ; Afshar, Abdollah (Supervisor)
    In this research Feasibility of application of oxide compounds of bismuth, molybdenum and tin as biocide was studied. So some epoxy paints with different ratio of these compounds were formulated. Afterward some tests were performed to assessment paints properties such as leaching rate, antifouling activity, adhesion, corrosion resistance and impact resistance. Results of leaching rate test showed that increase in the ratio of bismuth oxide from 10% to 60%, led to increase leaching rate from 0.029mg.day-1.cm-2 to 0.126mg.day-1.cm-2. beside that Microscopic results showed proved that the ratio of bismuth oxide in the cured coating is 25% of the paint formulate. In similar ratio of biocides,... 

    Designing of Integrated Polygeneration System of Heating, Power and Carbon Dioxide in Urban Wastewater Treatment Plants

    , M.Sc. Thesis Sharif University of Technology Movahhed, Paria (Author) ; Avami, Akram (Supervisor)
    With the growing development of urban communities and population, the demand for water and treated sewage water has grown significantly. The environmental damage of polluted water has resulted in passing of new and strict environmental laws on wastewater discharge recently. In the present research, a hybrid system involving a power, heat and cool cogeneration and a carbon dioxide capture system has been designed for a typical wastewater treatment plant. The plant is optimized from economic and environmental criteria. The anaerobic digester is modeled using the ADM1 model. The biogas is directed into the hydrogen sulfide removal filter to remove the impurities and into the heat exchanger to... 

    Development of a Multi Generation Energy System Based on Biotechnologies

    , M.Sc. Thesis Sharif University of Technology Taheri, Neda (Author) ; Roshandel, Ramin (Supervisor)
    In recent years, the issue of sustainability in the energy systems has attracted the attention of energy researchers. Using fossil fuels in common energy conversion systems cause environmental pollution, declining reserves of fossil resources and increase their prices because of the scarcity of fossil resources. Therefore, achieving the goals of sustainability necessitate using high efficiency energy conversion technology. Bio-inspired energy systems are one of the main candidates to improve energy conversion systems. The main target of this study is developing an optimal multi-generation energy system model, dynamically. MFC, Septic tank and Algae culture are integrated and produced power,... 

    Studying the Effective Factors and Optimizing Enzyme (α-amylase) Separation in Multi-Enzyme Systems by Agarose Column Chromatography

    , Ph.D. Dissertation Sharif University of Technology Ataallahi, Elahe (Author) ; Roosta Azad, Reza (Supervisor) ; Soheila Yaghmaee (Supervisor) ; Yeganeh Sarkandi, Shahin (Co-Supervisor)
    In all types of chromatography for the extraction and purification of proteins, a fixed substrate is needed with which the mobile phase containing the proteins interact with them. This fixed bed should contain grains that have characteristics such as sphericity, high surface area, hydrophilicity, binding power to functional groups, chemical stability, low specific absorption, reusability and low cost. Commercially, the most commonly substrates in the ranges of the molecular weight of proteins are agarose and dextran. Agar was extracted from Gracilaria salicornia seaweed and removal of ionic groups was investigated by three methods. In washing with isopropanol, the ionic groups were reduced... 

    Characterization of chlorella vulgaris and chlorella protothecoides using multi-pixel photon counters in a 3D focusing optofluidic system

    , Article RSC Advances ; Volume 7, Issue 8 , 2017 , Pages 4402-4408 ; 20462069 (ISSN) Vander Wiel, J. B ; Mikulicz, J. D ; Boysen, M. R ; Hashemi, N ; Kalgren, P ; Nauman, L ; Baetzold, S. J ; Powell, G. G ; He, Q ; Hashemi, N. N ; Sharif University of Technology
    Royal Society of Chemistry  2017
    Analysis of microparticle size and fluorescence intensity can be used to classify microparticles. We designed and fabricated an optofluidic system that characterizes microparticles, including fluorescent microparticles and microalgae. A new type of multi-pixel photon counter (MPPC) was employed to miniaturize the device, lower its power consumption, and make it insensitive to magnetic fields. The system uses a 635 nm laser for excitation of the microparticles' fluorescence. The scattered light from the fluorescent microparticles, as well as Chlorella vulgaris and Chlorella protothecoides, were measured. Additionally, we analyzed the width and height of the measured signals generated as a... 

    Experimental study and thermodynamic modeling for determining the effect of non-polar solvent (hexane)/polar solvent (methanol) ratio and moisture content on the lipid extraction efficiency from Chlorella vulgaris

    , Article Bioresource Technology ; Volume 201 , 2016 , Pages 304-311 ; 09608524 (ISSN) Malekzadeh, M ; Abedini Najafabadi, H ; Hakim, M ; Feilizadeh, M ; Vossoughi, M ; Rashtchian, D ; Sharif University of Technology
    Elsevier Ltd 
    In this research, organic solvent composed of hexane and methanol was used for lipid extraction from dry and wet biomass of Chlorella vulgaris. The results indicated that lipid and fatty acid extraction yield was decreased by increasing the moisture content of biomass. However, the maximum extraction efficiency was attained by applying equivolume mixture of hexane and methanol for both dry and wet biomass. Thermodynamic modeling was employed to estimate the effect of hexane/methanol ratio and moisture content on fatty acid extraction yield. Hansen solubility parameter was used in adjusting the interaction parameters of the model, which led to decrease the number of tuning parameters from 6... 

    Direct transesterification of wet microalgae to biodiesel using phosphonium carboxylate ionic liquid catalysts

    , Article Biomass and Bioenergy ; Volume 150 , 2021 ; 09619534 (ISSN) Malekghasemi, S ; Kariminia, H. R ; Plechkova, N. K ; Ward, V. C. A ; Sharif University of Technology
    Elsevier Ltd  2021
    In this study, four types of tetrabutylphosphonium carboxylate ionic liquids (ILs) were synthesized and used for a one-pot transesterification of wet Chlorella vulgaris (C. vulgaris) microalgae into fatty acid methyl esters (FAME) in the presence of methanol, as well as refined oils (sunflower, canola, and corn oil). The resulting process removed the need for complete drying and lipid extraction steps typically needed for biodiesel production from microalgae. The leading candidate ionic liquid catalyst, tetrabutylphosphonium formate ([P4444][For]), was further optimized using response surface methodology to minimize material consumption, increase water compatibility, reduce processing time... 

    Energy efficient cultivation of microalgae using phosphorescence materials and mirrors

    , Article Sustainable Cities and Society ; Volume 41 , 2018 , Pages 449-454 ; 22106707 (ISSN) Helali Esfahani, H ; Shafii, M. B ; Roshandel, R ; Sharif University of Technology
    Elsevier Ltd  2018
    In the present study, two novel annular photobioreactors (PBR) were developed to enhance microalgae growth. One of these photobioreactors used mirrors outside the PBR, while the other one utilized phosphorescence materials inside the PBR. The results of the study suggested that the use of mirrors and phosphorescence materials led to 70% and 30% increase, respectively, in the light intensity without any additional energy consumption. Further, the results revealed that when compared with the base case, the biomass concentration increased by 91% and 24% in PBR with mirrors and phosphorescence materials, respectively. In conclusion, an improvement in PBRs resulted in efficient light to biomass... 

    Synthesis and investigation of swelling behavior of new agar based superabsorbent hydrogel as a candidate for agrochemical delivery

    , Article Journal of Polymer Research ; Volume 16, Issue 6 , 2009 , Pages 655-665 ; 10229760 (ISSN) Pourjavadi, A ; Farhadpour, B ; Seidi, F ; Sharif University of Technology
    In this investigation a new type of superabsorbent hydrogel based on agar was prepared, and the effect of the feed ratio of some components (acrylic acid, MBA, APS and agar) on the swelling capacity of the hydrogel was systematically studied. Maximum water absorbency of the optimized final product was found to be 1,100∈g/g in distilled water. The structure of the hydrogel was characterized by FT-IR method and morphology of the samples was examined by scanning electron microscopy (SEM). Swelling properties of optimized hydrogel sample in different swelling mediums were investigated. The optimum hydrogel were also loaded with potassium nitrate and its potential for controlled release of... 

    Light harvesting and photocurrent generation by nanostructured photoelectrodes sensitized with a photosynthetic pigment: A new application for microalgae

    , Article Bioresource Technology ; Volume 163 , July , 2014 , Pages 1-5 ; ISSN: 09608524 Mohammadpour, R ; Janfaza, S ; Abbaspour Aghdam, F ; Sharif University of Technology
    Here in this study, successful conversion of visible light into electricity has been achieved through utilizing microalgal pigments as a sensitizer of nanostructured photo-electrode of dye-sensitized solar cells (DSSCs). For the first time, photosynthetic pigments extracted from microalgae grown in wastewater is employed to imitate photosynthesis process in bio-molecule-sensitized solar cells. Two designs of photoanode were employed: 10μm nanoparticular TiO2 electrode and 20μm long self-ordered, vertically oriented nanotube arrays of titanium dioxide films. Microalgal photosynthetic pigments are loaded on nanostructured electrodes and their photovoltaic performances have been investigated.... 

    Effect of various carbon sources on biomass and lipid production of Chlorella vulgaris during nutrient sufficient and nitrogen starvation conditions

    , Article Bioresource Technology ; Volume 180 , 2015 , Pages 311-317 ; 09608524 (ISSN) Abedini Najafabadi, H ; Malekzadeh, M ; Jalilian, F ; Vossoughi, M ; Pazuki, G ; Sharif University of Technology
    In this research, a two-stage process consisting of cultivation in nutrient rich and nitrogen starvation conditions was employed to enhance lipid production in Chlorella vulgaris algal biomass. The effect of supplying different organic and inorganic carbon sources on cultivation behavior was investigated. During nutrient sufficient condition (stage I), the highest biomass productivity of 0.158. ±. 0.011. g/L/d was achieved by using sodium bicarbonate followed by 0.130. ±. 0.013, 0.111. ±. 0.005 and 0.098. ±. 0.003. g/L/d for sodium acetate, carbon dioxide and molasses, respectively. Cultivation under nitrogen starvation process (stage II) indicated that the lipid and fatty acid content... 

    Biodiesel production from Spirulina microalgae feedstock using direct transesterification near supercritical methanol condition

    , Article Bioresource Technology ; Volume 239 , 2017 , Pages 378-386 ; 09608524 (ISSN) Mohamadzadeh Shirazi, H ; Karimi Sabet, J ; Ghotbi, C ; Sharif University of Technology
    Elsevier Ltd  2017
    Microalgae as a candidate for production of biodiesel, possesses a hard cell wall that prevents intracellular lipids leaving out from the cells. Direct or in situ supercritical transesterification has the potential for destruction of microalgae hard cell wall and conversion of extracted lipids to biodiesel that consequently reduces the total energy consumption. Response surface methodology combined with central composite design was applied to investigate process parameters including: Temperature, Time, Methanol-to-dry algae, Hexane-to-dry algae, and Moisture content. Thirty-two experiments were designed and performed in a batch reactor, and biodiesel efficiency between 0.44% and 99.32% was... 

    Inhibitory effects of functionalized indium doped ZnO nanoparticles on algal growth for preservation of adobe mud and earthen-made artworks under humid conditions

    , Article International Biodeterioration and Biodegradation ; Volume 127 , Febraury , 2018 , Pages 209-216 ; 09648305 (ISSN) Shariati, M ; Mallakin, A ; Malekmohammady, F ; Khosravi Nejad, F ; Sharif University of Technology
    Elsevier Ltd  2018
    In this article, indium doped ZnO nanoparticles (alloy nanoparticles) were investigated as inhibitors against algae growth on adobe mud and earthen artworks for surface preservation from destruction caused by micro-organisms under humid conditions, through surface modification and activation run off. Nanoparticles (NPs) were fabricated by physical vapor deposition (PVD) growth mechanism. The fabricated NPs were approximately 20 nm in size. The Chlorella vulgaris and Scenedesmus quadricauda were tested by application of indium doped ZnO nanoparticles (In/ZnO NPs) as inhibitors. As concentrations of NPs increased, the negative impacts of NPs on the algal growth were enhanced and physical... 

    The effect of different light intensities and light/dark regimes on the performance of photosynthetic microalgae microbial fuel cell

    , Article Bioresource Technology ; Volume 261 , 2018 , Pages 350-360 ; 09608524 (ISSN) Bazdar, E ; Roshandel, R ; Yaghmaei, S ; Mardanpour, M. M ; Sharif University of Technology
    Elsevier Ltd  2018
    This study develops a photosynthetic microalgae microbial fuel cell (PMMFC) engaged Chlorella vulgaris microalgae to investigate effect of light intensities and illumination regimes on simultaneous production of bioelectricity, biomass and wastewater treatment. The performance of the system under different light intensity (3500, 5000, 7000 and 10,000 lx) and light/dark regimes (24/00, 12/12, 16/8 h) was investigated. The optimum light intensity and light/dark regimes for achieving maximum yield of PMMFC were obtained. The maximum power density of 126 mW m−3, the coulombic efficiency of 78% and COD removal of 5.47% were achieved. The maximum biomass concentration of 4 g l−1 (or biomass yield... 

    Theoretical investigation on antioxidant activity of bromophenols from the marine red alga Rhodomela confervoides: H-atom vs electron transfer mechanism

    , Article Journal of Agricultural and Food Chemistry ; Volume 61, Issue 7 , 2013 , Pages 1534-1541 ; 00218561 (ISSN) Javan, A. J ; Javan, M. J ; Tehrani, Z. A ; Sharif University of Technology
    Bromophenols are known as antioxidant radical scavengers for some biomolecules such as those in marine red alga. Full understanding of the role played by bromophenols requires detailed knowledge of the radical scavenging activities in probable pathways, a focus of ongoing research. To gain detailed insight into two suggested pathways, H-atom transfer and electron transfer, theoretical studies employing first principle quantum mechanical calculations have been carried out on selected bromophenols. Detailed investigation of the aforementioned routes revealed that upon H-atom abstraction or the electron transfer process, bromophenols cause an increase in radical species in which the unpaired...