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Papers by Simin Naghizadeh

Research paper thumbnail of Recovery and Purification of Rhamnolipid from fermentation broth, by use of a Nanotechnology Process

New Biotechnology, Sep 1, 2012

Research paper thumbnail of Capability Evaluation of Rhamnolipid Biosurfactant purified by Magnetic Iron Oxide Nanoparticles for Emulsification of Water/n-decane Mixture

New Biotechnology, Sep 1, 2012

This study investigated the emulsification of n-decane in water using rhamnolipid biosurfactant, ... more This study investigated the emulsification of n-decane in water using rhamnolipid biosurfactant, purified by magnetic iron oxide nanoparticles. The emulsions formation at different volume ratios of biosurfactant solution to n-decane (3/1, 1/1, 1/3) and stirring rates (700, 1000, 1500 rpm) were assessed in order to achieve the optimum operational conditions. In addition, the effect of rhamnolipid purification on interfacial tension reduction of oil/water phases (n-decane as the oil phase and biosurfactant solution as the water phase) was also investigated. The results showed that the highest capability of emulsification observed at volume ratio of 1/1 and stirring rates above 1000 rpm. Moreover, under these conditions, by use of impure biosurfactant, the interfacial tension between two phases decreased from 27 mN/m-7 mN/m whereas by purified biosurfactant, the minimum interfacial tension measured as 1 mN/m. So the magnetic iron oxide nanoparticles could sufficiently separate impurities of biosurfactant and also the reduction of interfacial tension by purified biosurfactant in comparison with impure biosurfactant was so considerable.

Research paper thumbnail of 3 Microbial Enhanced Oil Recovery

Nowadays the majority of the world's energy comes from crude oil. A large proportion of this ... more Nowadays the majority of the world's energy comes from crude oil. A large proportion of this valuable and non-renewable resource is left behind in the ground after the application of conventional oil extraction methods. Moreover, there is a dire need to produce more crude oil to meet the worldwide rising energy demand which illustrates the necessity of progressing Enhanced Oil Recovery (EOR) processes. These methods try to overcome the main obstacles in the way of efficient oil recovery such as the low permeability of some reservoirs, the high viscosity of the crude oil, and high oil-water interfacial tensions that may result in high capillary forces retaining the oil in the reservoir rock (Bubela, 1987).

Research paper thumbnail of Capability Evaluation of Rhamnolipid Biosurfactant purified by Magnetic Iron Oxide Nanoparticles for Emulsification of Water/n-decane Mixture

New Biotechnology

This study investigated the emulsification of n-decane in water using rhamnolipid biosurfactant, ... more This study investigated the emulsification of n-decane in water using rhamnolipid biosurfactant, purified by magnetic iron oxide nanoparticles. The emulsions formation at different volume ratios of biosurfactant solution to n-decane (3/1, 1/1, 1/3) and stirring rates (700, 1000, 1500 rpm) were assessed in order to achieve the optimum operational conditions. In addition, the effect of rhamnolipid purification on interfacial tension reduction of oil/water phases (n-decane as the oil phase and biosurfactant solution as the water phase) was also investigated. The results showed that the highest capability of emulsification observed at volume ratio of 1/1 and stirring rates above 1000 rpm. Moreover, under these conditions, by use of impure biosurfactant, the interfacial tension between two phases decreased from 27 mN/m-7 mN/m whereas by purified biosurfactant, the minimum interfacial tension measured as 1 mN/m. So the magnetic iron oxide nanoparticles could sufficiently separate impurities of biosurfactant and also the reduction of interfacial tension by purified biosurfactant in comparison with impure biosurfactant was so considerable.

Research paper thumbnail of Recovery and Purification of Rhamnolipid from fermentation broth, by use of a Nanotechnology Process

Research paper thumbnail of Microbial Enhanced Oil Recovery

This Ph.D. dissertation dealt with microbial enhanced oil recovery focusing on adaptation of bact... more This Ph.D. dissertation dealt with microbial enhanced oil recovery focusing on adaptation of bacteria to some of subsurface conditions and the mechanisms of enhanced oil recovery through the use of microbes and their metabolic products. The core of this thesis consists of eight articles mostly dedicated to combination of different chemical and physical laboratory methods for experimentation, analysis and interpretation. These include flow injection, fermentation process, chromatographic assay, spectroscopy and image analysis to provide new, simple and robust solutions to understanding of processes during microbial enhanced oil recovery. A review of microbial enhanced oil recovery was presented to better comprehend the problem. The importance of mathematical models used in predicting the structural and morphological of bacteria cells during adaptation stages has been qualitatively discussed. The roles of biogenic acids and gases in carbonate rock dissolution and re-pressurization during microbial fluid rock interactions were also highlighted. The adapted bacteria strain were tested in different in formation waters from the North Sea and also, evaluated for improvement in oil recovery from packed columns by injection of bacteria solution to mimic in-situ oil recovery. Paper I and II presents models that explain the relationships between environmental parameters of pH, electrical conductivity, salinity and gas dissolution based on simple empirical models. This is valuable for understanding some of the interactions in the subsurface during the enhance oil recovery. The measured salinity is similar to those found in oil reservoirs. Paper III gives an overview of the adapted strain of Clostridium tyrobutyricum. The main objective of this study was to investigate the growth and metabolic products capability of this adapted strain and the potential to enhance oil recovery at elevated salinity. It was elaborated that quantities of some of the metabolites, gas, acids and biofilms have direct relationships with salinity of the medium and recovery of 38 % from sandstone and 25 % from chalk was achievable. Paper IV-V highlighted the microbial fluid rock interactions. It was found that porosity increase observed in all the rock samples was mainly due to significant dissolution of carbonate by the organic acids produced during microbial metabolism. The patterns of dissolution lead to reduction in the bulk volume of the chalk samples. The pore volumes were slightly reduced or generally remain the same and the release of Ca 2+ ions into microbial medium. v mobilitet i forbindelse med en forøget olieudvinding. Analyseresultater har også vist at alkaner i olien bliver nedbrudt af overfladeaktive stoffer, som bliver fremstillet af bakterier. Resultater af denne afhandling vil forhåbentlig bidrage til den fortsatte udvikling af MEOR og finde anvendelse i både den tekniske, såvel i den industrielle sektor.

Research paper thumbnail of Recovery and Purification of Rhamnolipid from fermentation broth, by use of a Nanotechnology Process

New Biotechnology, Sep 1, 2012

Research paper thumbnail of Capability Evaluation of Rhamnolipid Biosurfactant purified by Magnetic Iron Oxide Nanoparticles for Emulsification of Water/n-decane Mixture

New Biotechnology, Sep 1, 2012

This study investigated the emulsification of n-decane in water using rhamnolipid biosurfactant, ... more This study investigated the emulsification of n-decane in water using rhamnolipid biosurfactant, purified by magnetic iron oxide nanoparticles. The emulsions formation at different volume ratios of biosurfactant solution to n-decane (3/1, 1/1, 1/3) and stirring rates (700, 1000, 1500 rpm) were assessed in order to achieve the optimum operational conditions. In addition, the effect of rhamnolipid purification on interfacial tension reduction of oil/water phases (n-decane as the oil phase and biosurfactant solution as the water phase) was also investigated. The results showed that the highest capability of emulsification observed at volume ratio of 1/1 and stirring rates above 1000 rpm. Moreover, under these conditions, by use of impure biosurfactant, the interfacial tension between two phases decreased from 27 mN/m-7 mN/m whereas by purified biosurfactant, the minimum interfacial tension measured as 1 mN/m. So the magnetic iron oxide nanoparticles could sufficiently separate impurities of biosurfactant and also the reduction of interfacial tension by purified biosurfactant in comparison with impure biosurfactant was so considerable.

Research paper thumbnail of 3 Microbial Enhanced Oil Recovery

Nowadays the majority of the world's energy comes from crude oil. A large proportion of this ... more Nowadays the majority of the world's energy comes from crude oil. A large proportion of this valuable and non-renewable resource is left behind in the ground after the application of conventional oil extraction methods. Moreover, there is a dire need to produce more crude oil to meet the worldwide rising energy demand which illustrates the necessity of progressing Enhanced Oil Recovery (EOR) processes. These methods try to overcome the main obstacles in the way of efficient oil recovery such as the low permeability of some reservoirs, the high viscosity of the crude oil, and high oil-water interfacial tensions that may result in high capillary forces retaining the oil in the reservoir rock (Bubela, 1987).

Research paper thumbnail of Capability Evaluation of Rhamnolipid Biosurfactant purified by Magnetic Iron Oxide Nanoparticles for Emulsification of Water/n-decane Mixture

New Biotechnology

This study investigated the emulsification of n-decane in water using rhamnolipid biosurfactant, ... more This study investigated the emulsification of n-decane in water using rhamnolipid biosurfactant, purified by magnetic iron oxide nanoparticles. The emulsions formation at different volume ratios of biosurfactant solution to n-decane (3/1, 1/1, 1/3) and stirring rates (700, 1000, 1500 rpm) were assessed in order to achieve the optimum operational conditions. In addition, the effect of rhamnolipid purification on interfacial tension reduction of oil/water phases (n-decane as the oil phase and biosurfactant solution as the water phase) was also investigated. The results showed that the highest capability of emulsification observed at volume ratio of 1/1 and stirring rates above 1000 rpm. Moreover, under these conditions, by use of impure biosurfactant, the interfacial tension between two phases decreased from 27 mN/m-7 mN/m whereas by purified biosurfactant, the minimum interfacial tension measured as 1 mN/m. So the magnetic iron oxide nanoparticles could sufficiently separate impurities of biosurfactant and also the reduction of interfacial tension by purified biosurfactant in comparison with impure biosurfactant was so considerable.

Research paper thumbnail of Recovery and Purification of Rhamnolipid from fermentation broth, by use of a Nanotechnology Process

Research paper thumbnail of Microbial Enhanced Oil Recovery

This Ph.D. dissertation dealt with microbial enhanced oil recovery focusing on adaptation of bact... more This Ph.D. dissertation dealt with microbial enhanced oil recovery focusing on adaptation of bacteria to some of subsurface conditions and the mechanisms of enhanced oil recovery through the use of microbes and their metabolic products. The core of this thesis consists of eight articles mostly dedicated to combination of different chemical and physical laboratory methods for experimentation, analysis and interpretation. These include flow injection, fermentation process, chromatographic assay, spectroscopy and image analysis to provide new, simple and robust solutions to understanding of processes during microbial enhanced oil recovery. A review of microbial enhanced oil recovery was presented to better comprehend the problem. The importance of mathematical models used in predicting the structural and morphological of bacteria cells during adaptation stages has been qualitatively discussed. The roles of biogenic acids and gases in carbonate rock dissolution and re-pressurization during microbial fluid rock interactions were also highlighted. The adapted bacteria strain were tested in different in formation waters from the North Sea and also, evaluated for improvement in oil recovery from packed columns by injection of bacteria solution to mimic in-situ oil recovery. Paper I and II presents models that explain the relationships between environmental parameters of pH, electrical conductivity, salinity and gas dissolution based on simple empirical models. This is valuable for understanding some of the interactions in the subsurface during the enhance oil recovery. The measured salinity is similar to those found in oil reservoirs. Paper III gives an overview of the adapted strain of Clostridium tyrobutyricum. The main objective of this study was to investigate the growth and metabolic products capability of this adapted strain and the potential to enhance oil recovery at elevated salinity. It was elaborated that quantities of some of the metabolites, gas, acids and biofilms have direct relationships with salinity of the medium and recovery of 38 % from sandstone and 25 % from chalk was achievable. Paper IV-V highlighted the microbial fluid rock interactions. It was found that porosity increase observed in all the rock samples was mainly due to significant dissolution of carbonate by the organic acids produced during microbial metabolism. The patterns of dissolution lead to reduction in the bulk volume of the chalk samples. The pore volumes were slightly reduced or generally remain the same and the release of Ca 2+ ions into microbial medium. v mobilitet i forbindelse med en forøget olieudvinding. Analyseresultater har også vist at alkaner i olien bliver nedbrudt af overfladeaktive stoffer, som bliver fremstillet af bakterier. Resultater af denne afhandling vil forhåbentlig bidrage til den fortsatte udvikling af MEOR og finde anvendelse i både den tekniske, såvel i den industrielle sektor.