جستجوی مقالات مرتبط با کلیدواژه « سورفکتانت » در نشریات گروه « شیمی »

In this research, the effect of titanium oxide nanoparticles on the performance of saponin and sodium dodecyl sulfate biosurfactants in cleaning heavy crude oil storage tank was investigated. Also, after the clean up process, sodium dodecyl sulfate, saponin and titanium oxide nanoparticles were used to recover the oil from the residual sludge of crude oil storage tanks on a laboratory scale. The results showed that the optimal amount of HLB for the extraction process was about 24.1 for a mixture of 40% sodium dodecyl sulfate and 60% saponin. The results also showed that the simultaneous use of surfactants and nanoparticles leads to a synergistic effect that significantly increases the efficiency of the extraction process. The maximum residual amount of oil in the sludge under optimal conditions was about 3.6 (HLB value = 24.1 for a mixture of surfactants and 3 g / l titanium oxide nanoparticles). This value was 92.5% and 93.7% for each of the surfactants without the presence of titanium oxide nanoparticles for saponin and sodium dodecyl sulfate. The results of the present study showed that this method has the potential for industrial applications and can be used in oil recycling from petroleum sludge.

The importance of hydrocarbons in the production of various materials, as well as the supply of most part of the world's energy in the last century and the inability to replace renewable energy due to the rapid growth of global energy demand, on the other hand, has led to the extraction of hydrocarbon reserves should not be out of the focus of researchers and experts in this industry. One of the most important methods of Enhanced Oil Recovery (EOR), especially in carbonate reservoirs, is wettability alteration of the rock using chemical flooding, which has recently been considered by many researchers and research centers. Since most of the world's reservoirs, as well as our beloved country, are made of carbonates, changing the wettability of reservoir rock from oil to water wet have a significant effect on increasing the final recovery factor of the reservoir. The present study is an overview of the latest achievements of EOR through chemical flooding in carbonate reservoirs aimed at changing the wettability towards hydrophilicity. Despite extensive research on the mechanism of chemical flooding, not all aspects of it have been clarified so far. Obviously, without a comprehensive and accurate knowledge of the mechanism of this process, it will not be possible to control and improve it.in the work at hand mechanism of chemical flooding using low salinity, surfactants, polymers, nanoparticles or Nano fluids has been reviewed and an attempt is made to investigate the interactions of surface rock minerals, ions in the injection fluid, crude oil and formation brine be reviewed.

Nano-structure of new Cu(II) coordination compound,[Cu(DPC)(H2O)3] was synthesized by sonochemical method. The new nano-structure was characterized by scanning electron microscopy(SEM), X-Ray powder Diffraction (XRD), IR spectroscopy, elemental analyses, and UV-Vis spectroscopy. The thermal stability of the compound has been studied by thermal gravimetric and differential thermal analyses. Copper oxide nanoparticles were obtained by direct calcination of the compound at 450, 500,550, and 600 under air atmospheres have different morphologies of nano-sized CuO. Also, the Nanoparticle of CuO was obtained by thermolysis of nano complexes in 180 with oleic acid as surfactant.

In this study, the micellization behavior of the sodium cholate (SCH) and sodium dodecyl sulfate (SDS), in aqueous solution in pure state, and mixture of them (SCH + SDS) in different mole fractions were investigated by conductometric method at 298.15 K. The obtained data from experimental measurements were used to determination of the critical micelle concentration (CMC) of surfactants in pure and mixed state. Also according to Regular Solution Theory (RST), were calculated the following parameters: the interaction parameter between surfactants in the mixed system (), activity coefficient (،), mole fractions of the components in the mixed micelle (,) and thermodynamic parameters such as Gibbs free energy of micellization () and excess free energy (). The results obtained show that in the anionic-anionic mixture, the interaction parameter is low and the activity coefficients show a small deviation from the ideal state, the standard Gibbs free energy of micellization () are negative values, this shows that the micelle formation process take place spontaneously.

Photo-Fenton oxidation is one of the most efficient advanced oxidation process that is used for the treatment of effluents containing recalcitrant compounds. In this research, the removal of an anionic surfactant, sodium dodecyl sulfate, by MnFe2O4/ZnO nanocatalyst using photo-Fenton advanced oxidation process has been investigated. In this study, the MnFe2O4/ZnO nanocomposite was firstly synthesized and characterized, and then applied in the photo-Fenton oxidation process under UV irradiation. The effect of different parameters, such as pH, catalyst dose and the amount of hydrogen peroxide, on the process were investigated. Under the optimum conditions, at pH = 7, with a surfactant concentration of 5 mg/L, at 30 min using 2.24 mL hydrogen peroxide, the surfactant removal efficiency was 100%. The results show that the proposed method using the synthesized nanocatalyst has a high efficiency in the removal of surfactants.

Some of the biological processes, such as mutation, protein misfolding and/or partially unfolding may cause the formation of amyloid fibrils, which have a diameter of nanometer range and a length up to many microns. Extensive studies have demonstrated that the formation of fibrils is associated with a variety of human disorders, such as Alzheimer’s disease, Parkinson’s disease, Huntington’s diseases, type II diabetes, and so on. Therefore, inhibiting fibril formation or disrupting preformed mature fibrils could be beneficial strategies for the treatment of fibril-related diseases. Other investigations have revealed that fibrils feature several fundamental properties, including high structural stability. Thus, they are increasingly exploited for a broad range of applications in Nano biotechnology, such as nanotubes and nanowires. In these cases, materials and compounds that stimulate the in vitro formation of fibrils may contribute to the development of these applications.

So far, various methods have been proposed for the synthesis of hydroxyapatite nanoparticles as the main ingredient in bone and enamel. In each of these methods, by varying initial conditions of synthesis, samples of size and shape, and the ratio of length to diameter can be achieved. In this study, pure hydroxypropyl nanoparticles were prepared using calcium nitrate precursors (Ca (NO3) 2-4H2O) and diammonium hydrogen phosphate ((NH4) 2HPO4) by hydrothermal method. The purpose of this study was to investigate the effects of changes in reaction conditions and the synthesis of this material on the size and shape of the particles. X-ray diffraction (XRD) and scanning electron microscopy (SEM) nanoparticles were investigated. The results of the experiment indicate that the concentration of the raw materials, the method and temperature of calcining, the speed of the addition of materials, the use or non-use of surfactants can have different effects on the size and shape of the hydroxyapatite particles.

In this research, nanoparticles of manganese oxide were prepared nano-complex Poly-diaqua- µ -2,3-pyrazine dicarboxylato manganese(II) dehydrate {[ Mn(pyzdc)(H2O)2]x .2xH2O} With calcination at different temperatures and surfactant oleic acid at 180°C temperatures. Temperature and surfactant has important roles in shape and size of nanoparticles. Manganese oxide nanoparticles by FT-IR spectra and XRD and SEM images were studied.

A considerable quantity of the world’s oil reserve is located in naturally fractured carbonate reservoirs, with very low oil recovery efficiency, due to their wettability abd tightness of matrix. Recovery efficiency can be improved considerably, if the reservoir rock wettability is changed from mostly oil-wet to water-wet, thus enhancing water imbibition into the oil saturated rock. Smart water is able to alter the carbonate rock wetability from oil-wet to intermediate to water-wet, and therefor, water imbibition into the rock matrix is facilitated. In this study, the effect of ions and different surfactants concentration in the smart water on the wettability state of carbonate rocks was investigated by contact angle measurements and spontaneous imbibition experiments. Imbibition experiments were performed at three temperature level(50, 70 and 90 C). The effect of ions, temperature, and surfactant concentration on the wettability alteration of carbonate rocks during spontaneous imbibition process were invistegated. The results showed that the presence of SO42- ions, the strongly affects the wetting state of carbonate rocks, and increasing SO42- concentration from 0.033 mol/l to 0.1 mol/l increased the oil recovery from 19% to 58%. Moreover, by increasing Mg2 concentration the oil recovery increases (from 19% to 23%). Also the presense of cationic surfactant C12TAB, strongly changed the wetting state of carbonate rocks, and also increased the oil recovery from 19% to 78%.

In this work, we used co-precipitation method for synthesis of coper chromite(CuCr2O4.CuO). Three mole ratios of Cu2ﰪ (0.4, 0.7 and1.0) was used in order to investigate the effect of these mole ratios on the phase, morphology and size of particles. Precursor samples were calcined at 500, 600 and 700ºC for each mole ratio in order to investigate the effect of calcination temperatures. Furthermore two samples were calcined at 800 and 900 ºC and two samples synthesized in the presence of sodium dodecyl sulphate as surfactant at 700 ºC. All samples were characterized by Xray diffraction (XRD), scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) analysis. XRD patterns of nanoparticles calcined at 500, 600 and 700ºC revealed that, at this range of temperature, nanoparticles have been composed of CuCr2O4 spinel and CuO. Furthermore XRD patterns showed that by changing mole ratio of Cu2ﰪ the amount of CuO remains constant at 500 and 600 ºC calcination temperatures but at higher temperature (700 ºC) the amount of CuO increases by increasing mole ratio of Cu2ﰪ. At 800 and 900 ºC calcination temperatures and Cu2ﰪ =1, CuCr2O4 spinel was not seen, this compound reacts with CuO and produces CuCrO2 at these temperatures.
SEM images of nanoparticles at 500, 600 and 700ºC calcination temperatures showed that the morphology of nanoparticles is almost like nanosheet with a thickness in the range of 20-35 nm. Big aggregation is seen due to small particle size. The best nanoparticle according to uniformity of morphology and small particle size is the sample that Cu2ﰪ is 0.4 and is calcined at 600ºC. With rising temperature and using surfactant, the aggregation reduces and crystallinity improves but the size of nanoparticles becomes large.

The enhanced oil recovery from oil wet carbonate rocks using wettability alteration mechanism by surface active compounds was investigated. The imbibition tests were done by two typical anionic and cationic surfactants, sodium dodecyl sulfate and hexadecyltrimethylammonium bromide, respectively. The experiments were carried out at one of the Iranian oil reservoir condition. The efficiency of oil recovery by anionic surfactant was approximately equal to brine imbibition at reservoir condition. The results showed that the cationic surfactants have the high potential for enhanced oil recovery by spontaneous imbibition.

In this research the effect of three non-ionic surfactants named PEG-1000, KELA-2 and KECA-20 at four levels of 1, 2, 3 and 4 % on CMP pulping of Eucalyptus Camaldulensis, oxidative bleaching of selected pulps and strength of handsheet papers were investigated.The resulting pulps with higher screen yield and lower reject from application of each surfactant as well as the reference CMP pulps (without surfactant) were selected and bleached in two stages with H2O2. The pulping results showed that application of KECA-20 at the level of 1% increased accepted yield by about 2.5%. KECA-20 (1%) and PEG-1000 (4%) at the level of 1% lowered the consumption of bleaching agents and increased brightness and decreased opacity and yellowness of pulp. In addition, application of surfactants increased strength of handsheet papers compared to the paper obtained from the reference CMP pulp.

In order to decrease the Kappa number and bleaching environmental impacts, the effect of several ionic surfactants on delignification and bleachability of bagasse soda pulping were investigated. Results indicated that the applying 1% of some surfactant decreased significantly the Kappa number at the same level of pulp yield. Moreover, addition of surfactant reduced alkali consumption, pulping reject and improved brightness and freeness of pulp. Compared to reference pulp, the pulp obtained with surfactant application produced higher brightness at the same level of chlorine dioxide charge during the bleaching of pulp with DoED1 and DoEpD1 sequences. Resulted pulps had a better Mechanical properties regarding to conventional reference pulp.