Farhad Salimi

Preparation and investigation of the physical and chemical properties of clay-based polyacrylamide/Cr (III) hydrogels as a water shut-off agent in oil reservoirs

The effects of clay (montmorillonite and kaolinite) in the hydrogels were investigated on various properties such as syneresis and strength of thermal and salinity situations in one of the southern Iranian oil reservoirs. The X-ray diffraction (XRD) patterns exhibited a significant increase in interplanar spacing between the montmorillonite clay layers, varying from the initial value of 12.43 °A to 19.45 °A, which evidences the intercalation formation. It was revealed that even increasing of the interlayer spacing due to kaolinite modification had no effect on the clay compositions. Formation water was used to study the strength of the hydrogel in the presence of ions. The results indicated that 15 wt% increase of kaolinite clay (modified and non-modified) leads to 20% decrease of the hydrogels’ syneresis. The diffusion of polymer chains between the clay layers increased the elastic modulus (G′) of the prepared hydrogels with modified kaolinite and montmorillonite, where the maximum value of G’ was observed in 3 wt% of montmorillonite. Finally, the thermogravimetric analysis (TGA) indicated an increase in the thermal stability of the mentioned hydrogels.

Erratum to: Investigation of asphaltene deposition under dynamic flow conditions

Unfortunately, in the original published article the name of the author Mozafar Abdollahifar was spelled incorrectly. It should read as ‘‘Mozaffar Abdollahifar’’. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Investigation of asphaltene deposition under dynamic flow conditions

Asphaltene deposition is one of the most serious problems, which usually occurs in oil wells, petroleum production, oil processing, and transportation facilities. Deposition of heavy organic components, especially asphaltene, can lead to wellbore blockage and impacts well economics due to reduction in oil production. Therefore, it is necessary to pay more attention to finding some solution to overcome this problem. In this study, a pipe-loop apparatus for investigation of oil stability was employed to measure deposition thickness using a thermal method. The effects of many factors such as oil type, oil temperature, oil velocity, inhibitors, and solvents on asphaltene deposition were investigated. The results showed that the deposition increased with the increasing value of the colloidal instability index. Besides, the deposition thickness increased with the decreasing velocity of oil, but did not change with oil temperature. In addition, n-heptane could result in more deposition; however, toluene had no effect on the deposition. Branched dodecyl benzene sulfonic acid (Branched DBSA) and Linear DBSA as inhibitors decreased the rate of asphaltene deposition.

Naked Eye Detection of Cr 3+ and Ni 2+ Ions by Gold Nanoparticles Modified with Ribavirin

This paper reports the synthesis of ribavirin-modified gold nanoparticles (ribavirin-AuNPs) in aqueous media, characterized by FTIR spectroscopy, ultraviolet–visible spectroscopy (UV–vis), and transmission electron microscopy (TEM). Ribavirin-AuNPs were employed as colorimetric probes to detect Cr3+ and Ni2+ in the pH range of 3–8 and 25 ∘C in aqueous solutions by the color change of the system. In the solution, ribavirin-AuNPs were red in color and the surface plasmon absorption band was centered at 530 nm. In the presence of Cr3+ and Ni2+, ribavirin-AuNPs induced the aggregation of nanoparticles, and the surface plasmon absorption changed to 540 nm. Upon aggregation, the surface plasmon absorption band red-shifted and, thus, the nanoparticle solution appeared blue. The sensitivity of ribavirin-AuNPs toward other metal ions, i.e. Mg2+, Mn2+, Cr6+, Na+, Ni2+, Ag+, Al3+, Ca2+, Cd2+, K+, Cd2+, Cu2+, Fe2+, Fe3+, Hg2+, Co3+, Ni2+, Pb2+, and Zn2+, was negligible. This highly selective sensor allowed for the direct quantitative assay of Ni2+ and Cr3+. The limits of detections were found to be 25.2 and 30.5 nM for Ni2+ and Cr3+ on the basis of the signal-to-noise ratio of 3:1 and correlation coefficients (R2) of 0.9813 and 0.99489 for Ni2+ and Cr3+, respectively.

Removal of Arsenic and Copper from Water Solution Using Magnetic Iron/Bentonite Nanoparticles (Fe3O4/Bentonite)

Heavy metal pollution is one problem in the water purification industry, which causes extreme risk aversion. The purpose of this study was to investigate the removal of arsenic (As) and copper (Cu) from water by nanoparticles of magnetic iron bentonite (Fe3O4/bentonite). Fe3O4/bentonite nanoparticles were prepared by chemical co-precipitation method. The synthesized samples were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction patterns (XRD) techniques. The results of the XRD and FTIR confirmed the successful synthesis of the Fe3O4/bentonite nanoparticles. The results of the SEM showed that the Fe3O4/bentonite nanoparticles had symmetrical, bullet-shaped particles with uniform size. Then, by performing modular experiments, the effect of time, temperature and pH parameters was investigated on the pollutants adsorption rate in an aqueous solution. The results showed that the adsorption capacity for ions increased by increasing the contact time, temperature and adsorbent dosage of the solution The results indicated that the optimum condition was achieved at temperature of 75 ∘C, reaction time of 120 min, the adsorbent dosage of 5 g/l and pH of 6 and 4 for Cu and As, respectively. Langmuir and Freundlich isotherms were employed to modeling of the experimental results. The best results in the modeling prosess for the experiment results were obtained based on the Freundlich isotherm. The kinetic data were also analyzed through pseudo-first-order and pseudo-second-order models. The pseudo-first-order kinetic model well depicted the kinetics of heavy metals ions adsorption on adsorbent.

Prediction of asphaltene deposition during turbulent flow using heat transfer approach

ABSTRACT In this study, asphaltene deposition from crude oil has been studied experimentally using a test loop and prediction using theoretical study under turbulent flow (Reynolds numbers below 5000). The effects of many parameters such as oil velocity, surface temperature and concentration of flocculated asphaltene on the asphaltene deposition were investigated. The results showed that asphaltene deposition thickness increases with increasing both surface temperature and concentration of flocculated asphaltene and decreasing oil velocity. Thermal approach was used to describe the mechanisms involved in this process and the results of data fitting showed that there are good agreements between the results of the proposed model and the measured asphaltene deposition rates.

Removal of methylene blue from water solution by modified nano-boehmite with Bismuth

ABSTRACT In this study, modified nano- boehmite was synthesized with Bismuth and used to adsorb of methylene blue dye solution. Identify the adsorbents synthesized by SEM, FTIR, XRD, TEM and BET have been conducted. The effect of experimental parameters pH, contact time, temperature and initial concentration were studied on adsorption. Results indicated that pH optimum at 25°C is 7 and adsorption reaches equilibrium after 30 minutes. The optimum adsorbent amount is 0.01 g. The results indicated that the equilibrium data were perfectly represented by the Langmuir isotherm and the adsorption behavior can be better described by pseudo-second-order model.

The effect of a TEG additive on hydrate formation

ABSTRACT In gas industry, gas hydrate formation has both advantages and disadvantages. The best advantage of gas hydrate is Persian Gulf water sweetening, carbon dioxide capture, and gas storage, and its drawbacks are pressure drop, plugging, and explosion in pipelines. In recent years, using the inhibitors to prevent hydrate formation is being considered among researchers. In this study, the new equilibrium data for hydrate formation of inlet natural gas to Gachsaran NGL-1200 refinery with addition of Tri ethylene glycol (TEG) with mass concentration of 5% and 15% in distilled and Persian Gulf waters were measured by constant-volume method. The experimental results show that the hydrate formation conditions will be hard with the increase of TEG concentration in distillated and Persian Gulf waters. In other words, TEG addition to Persian Gulf water had more inhibitory effect in hydrate formation than TEG addition to distilled water. The hydrate formation temperature, in pressure range of 28–29 bars, reduced 0.3°C and 2.7°C for distilled water and 2.8°C and 4.6°C for Persian Gulf water in presence of TEG with mass concentration of 5% and 15%, respectively.