Sharif Digital Repository

Evidently, environment contamination by water insoluble chemicals present at the industrial wastes could bring about catastrophic consequences to the biosphere. Biological based cleaning technologies are commonly considered as a practical remedy to remove these contaminations. In fact, these techniques are founded on the ability of certain microorganisms to degrade the contaminants. It is crystal clear that the availability of contaminants to the microorganisms is an essential parameter determining the final efficiency of the biodegradation process. In practice, the limited solubility of the contaminants in the aqueous phase leads to mass transfer constraints which consequently, decrease the... 

In this research, the behavior of surfactin at the presence of water, decane, and asphaltene is investigated. Decane is chosen instead of crude oil to simplify the model. In the first chapter, basic molecular structures are introduced. Furthermore, in the second chapter molecular dynamics simulation, as the main tool in these simulations, is introduced. In the third chapter, one of the most important quantities in chemical engineering, diffusion coefficient, is chosen to investigate the efficiency and accuracy of molecular dynamics simulation method to calculate such a quantity and results show that molecular dynamics simulation can present accurate quantities, more accurate than common... 

To investigate the role of biological processes in bacterial transport through poroud media, six rod shaped and motile bacteria were isolated from a crude oil sample. A multi stage screening procedure was utilized to select the most appropriate isolate in microbial enhanced oil recovery applications (MEOR). It was identified and registered as Bacillus licheniformis MS3 in GenBank database. After that, the physical properties and chemical structure of its biosurfactant were determined and it was proved to be a new lipopeptide biosurfactant which was called licheniformin. Power law logistic model was utilized to investigate the kinetics growth of the MS3 strain on insoluble carbon sources ... 

The effects of biosurfactants on sandstone rocks are known in the literature. However, there are few examples of experimental works in Iranian carbonate reservoirs dealing with the effects of biosurfactants under reservoir conditions. This thesis discusses the effect of an efficient biosurfactant produced from Pseudomonas aeroginosa MRo1, a bacterial strain isolated from oil excavation areas in southern Iran, on the recovery of residual oil trapped within carbonate rocks was investigated. The MRO1 could reduce surface tension from 72 to 28 dyne/cm. It also could reduce Interfacial tension from 18.382 to 5.646 dyne/cm.
In a core holder set-up bearing four limestone- and... 

Biosurfactants are surface active compounds capable of reducing surface tension and interfacial surface tension. Biosurfactants are produced by a variety of microorganisms. They are promising replacements for chemical surfactants because of biodegradability, non-toxicity and being able to produce from renewable sources. However a major problem of producing biosurfactant in industrial level is their production cost. In this research, by using corn steep liquor as low-cost nitrogen source besides other nitrogen sources, not only production cost reduced but also a higher efficiency achieved. Therefore optimization of biosurfactant production was done by RSM and Box- Behnken method. Results... 

Polyaromatic hydrocarbons are toxic compounds generally produced by combustion of explosives and petroleum materials. They cause soil and ground water contamination. PAHs are carcinogenic and lead to serious health problems for human and other living things; hence they should be removed from the environment. Soil washing technique has been one of methods applied for soil treatment during the years and surface active compounds like emulsifiers and surfactants have been introduced into washing process to improve the removal efficiency. On the other hand, synthetic surfactants made of chemicals and petroleum materials are not degradable and remain in the environment. To void this secondary... 

This research was done for feasibility evaluation and understanding correct microbial enhanced oil recovery(MEOR) procedure for carbonate reservoirs. With the aim of cost reduction and possible activation of smart water mechanisms, sea water used as a base for MEOR process. Two biosurfactant producing strains were isolated from oil contaminated water and soil, and one halotolerant strain, from sea water. Optimization of biosurfactant yield was conducted and two new definitions for optimum point, by considering economical and technical facts, were proposed. Partial characterization of produced biosurfactant was carried out through FTIR and NMR analysis and the produced biosurfactant was... 

As fossil fuels are still the world's most important source of energy, as well as the maturity of most of the world's oil reservoirs, there is a need for enhanced oil recovery methods to meet the world's increasing oil demands. MEOR methods are new and promising methods that are still in the research and development stage. One of the MEOR methods is the use of biosurfactants, which increase the oil recovery by two mechanisms: 1) reducing the interfacial tension between water and oil and 2) changing the wettability of the rock. In this study, the performance of two glycolipid biosurfactants, rhamnolipid and sophorolipid, in increasing oil recovery has been investigated. Initially, surface...