Hosein Ghaedi

Effect of Aging, Antioxidant, and Mono- and Divalent Ions at High Temperature on the Rheology of New Polyacrylamide-Based Co-Polymers

The viscosity of four new polymers was investigated for the effect of aging at high temperature, with varying degrees of salinity and hardness. The four sulfonated based polyacrylamide co-polymers were FLOCOMB C7035; AN132 VHM; SUPERPUSHER SAV55; and THERMOASSOCIATIF copolymers. All polymer samples were aged at 80 °C for varying times (from zero to at least 90 days) with and without isobutyl alcohol (IBA) as an antioxidant. To see the effect of divalent ions on the polymer solution viscosity, parallel experiments were performed in a mixture of CaCl2-NaCl of the same ionic strength as 5 wt % NaCl. The polymers without IBA showed severe viscosity reduction after aging for 90 days in both types of preparation (5 wt % NaCl or CaCl2-NaCl). In the presence of IBA, viscosity was increased when aging time was increased for 5 wt % NaCl. In CaCl2-NaCl, on the other hand, a viscosity reduction was observed as aging time was increased. This behavior was observed for all polymers except AN132 VHM.

Assessment of Polyacrylamide Based Co-Polymers Enhanced by Functional Group Modifications with Regards to Salinity and Hardness

This research aims to test four new polymers for their stability under high salinity/high hardness conditions for their possible use in polymer flooding to improve oil recovery from hydrocarbon reservoirs. The four sulfonated based polyacrylamide co-polymers were FLOCOMB C7035; SUPERPUSHER SAV55; THERMOASSOCIATIF; and AN132 VHM which are basically sulfonated polyacrylamide copolymers of AM (acrylamide) with AMPS (2-Acrylamido-2-Methylpropane Sulfonate). AN132 VHM has a molecular weight of 9–11 million Daltons with 32 mol % degree of sulfonation. SUPERPUSHER SAV55 mainly has about 35 mol % sulfonation degree and a molecular weight of 9–11 million Daltons. FLOCOMB C7035, in addition, has undergone post-hydrolysis step to increase polydispersity and molecular weight above 18 million Daltons but it has a sulfonation degree much lower than 32 mol %. THERMOASSOCIATIF has a molecular weight lower than 12 million Daltons and a medium sulfonation degree of around 32 mol %, and also contains LCST (lower critical solution temperature) type block, which is responsible for its thermoassociative characteristics. This paper discusses the rheological behavior of these polymers in aqueous solutions (100–4500 ppm) with NaCl (0.1–10 wt %) measured at 25 °C. The effect of hardness was investigated by preparing a CaCl2-NaCl solution of same ionic strength as the 5 wt % of NaCl. In summary, it can be concluded that the rheological behavior of the newly modified co-polymers was in general agreement to the existing polymers, except that THERMOASSOCIATIF polymers showed unique behavior, which could possibly make them a better candidate for enhanced oil recovery (EOR) application in high salinity conditions. The other three polymers, on the other hand, are better candidates for EOR applications in reservoirs containing high divalent ions. These results are expected to be helpful in selecting and screening the polymers for an EOR application.

Toxicity of Several Potassium Carbonate and Phosphonium-Based DeepEutectic Solvents towards Escherichia coli and Listeria monocytogenesBacteria

Deep eutectic solvents (DESs) and ternary deep eutectic solvents (TDESs) and are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, the several DESs and a TDES were prepared. Allyltriphenyl phosphonium bromide and potassium carbonated were selected as HBAs to mix with various HBDs such as glycerol (GL), ethylene glycol (EG), diethylene glycol (DEG) and triethylene glycol (TEG) into different molar ratios. Two different groups of bacteria were selected for investigation of toxicity of species, namely Escherichia coli (EC) as a Gram negative bacterium and Listeria monocytogenes (LM) as a Gram positive bacterium. The results revealed that by increasing alkyl chain length on HBD, the toxicity of DESs increases towards EC bacterium. However, there appears to have no direct relationship between effect of alkyl chain length and toxicity DESs towards LM bacterium. Moreover, by studying the effect of molar ratio the toxicity of DESs, it was observed that there is no direct relationship between them. Furthermore, it was found that the type of HBD has a dominant effect on the toxicity of DESs compared to type of salt. By comparing the toxicity of DESs in this work with that of ILs in literature, it was found that DESs are less toxic than ILs. The last interesting result of this work is that TDES exhibited the lowest toxicity on EC and LM bacteria compared with DESs.

The effects of salt, particle and pore size on the process of carbon dioxide hydrate formation: A critical review

Hydration is an alternative method for CO2 capture. In doing so, some researchers use porous media on an experimental scale. This paper tries to gather the researches on the formation of CO2 hydrate in different types of porous media such as silica sand, quartz sand, Toyoura, pumice, and fire hardened red clay. This review has attempted to examine the effects of salt and particle sizes as two major factors on the induction time, water to hydrate conversion, gas uptake (or gas consumption), and the rate of CO2 hydrate formation. By performing a critical assessment of previous research works, it was observed that the figure for the gas uptake (or gas consumption) and water to hydrate conversion in porous media was decreased by increasing the particle size provided that the pore size was constant. Although, salt can play a role in hydrate formation as the thermodynamic inhibitor, the results show that salt can be regarded as the kinetic growth inhibitor and kinetic promoter. Because of the fact that the gas ...