Loading...
Search for:
aqueous-solution
0.005 seconds
Total 128 records
Asphaltene destabilization in the presence of an aqueous phase: The effects of salinity, ion type, and contact time
, Article Journal of Petroleum Science and Engineering ; Volume 208 , 2022 ; 09204105 (ISSN) ; Hosseini, A ; Fatemi, M ; Andersen, S. I ; Ayatollahi, S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
One of the possible fluid-fluid interactions during water-flooding in oil reservoirs, that is still debated, is the effect of injected brine salinity on asphaltene destabilization. If asphaltene precipitation is induced by salinity changes in the oil reservoirs and surface facilities, this could have a massive impact on the economy of a low salinity water-flooding project. Therefore, this study aims to investigate the effect of brine salinity on the amount of asphaltene precipitation and the governing destabilization mechanisms. Direct asphaltene precipitation measurements, along with the analyses of optical microscopy images and ion chromatography (IC), indicate that the asphaltene...
Adsorption of petroleum monoaromatics from aqueous solutions using granulated surface modified natural nanozeolites: Systematic study of equilibrium isotherms
, Article Water, Air, and Soil Pollution ; Volume 217, Issue 1-4 , 2011 , Pages 611-625 ; 00496979 (ISSN) ; Torabian, A ; Kazemian, H ; Bidhendi, G. N ; Azimi, A. A ; Charkhi, A ; Sharif University of Technology
Abstract
Petroleum monoaromatics including benzene, toluene, ethylbenzene, and xylenes (BTEX) are among the notorious volatile organic compounds that contaminate water and soil. In this study, a surfactant- modified natural zeolite and its relevant granulated nanozeolites were evaluated as potential adsorbents for removal of petroleum monoaromatics from aqueous solutions. All experiments performed in batch mode at constant temperature of 20°C and pH of 6.8 for 48 h. The results revealed that the amount of BTEX uptake on granulated zeolites nanoparticles were remarkably higher than the parent micron size natural zeolite (in the order of four times). The isotherms data were analyzed using five models...
Mechanistic study of wettability alteration of oil-wet calcite: The effect of magnesium ions in the presence and absence of cationic surfactant
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 482 , October , 2015 , Pages 403-415 ; 09277757 (ISSN) ; Al Maamari, R. S ; Ayatollahi, S ; Mehranbod, N ; Sharif University of Technology
Elsevier
2015
Abstract
Over 60% of the world's discovered oil reserves are held in carbonate reservoirs, which are mostly naturally fractured. Conventional water flooding results in low oil recovery efficiency in these reservoirs as most of them are oil-wet. On account of negative capillary forces, injected brine cannot penetrate simply into an oil-wet matrix of fractured formations to force the oil out. Wettability alteration of the rock surface to preferentially more water-wet state has been extensively studied using both smart water and surfactants separately. This study aims to study the effects of Mg2+ as one of the most important wettability influencing ions on the wetting properties of oil-wet carbonate...
Resorcinol-formaldehyde xerogel as a micro-solid-phase extraction sorbent for the determination of herbicides in aquatic environmental samples
, Article Journal of Separation Science ; Volume 38, Issue 13 , 2015 , Pages 2305-2311 ; 16159306 (ISSN) ; Zare, M ; Piri Moghadam, H ; Bagheri, H ; Sharif University of Technology
Abstract
In this study, organic aerogels were synthesized by the sol-gel polycondensation of mixed cresol with formaldehyde in a slightly basic aqueous solution. Carbon aerogels and xerogels are generated by pyrolysis of organic aerogels. The novel sol-gel-based micro-solid-phase extraction sorbent, resorcinol-formaldehyde xerogel, was employed for preconcentration of some selected herbicides. Three herbicides of the aryloxyphenoxypropionate group, clodinafop-propargyl, haloxyfop-etotyl, and fenoxaprop-P-ethyl, were extracted from aqueous samples by micro-solid-phase extraction and subsequently determined by gas chromatography with mass spectrometry. The effect of different parameters influencing the...
Biodesulfurization of dibenzothiophene by a newly isolated Rhodococcus erythropolis strain
, Article Bioresource Technology ; Volume 101, Issue 3 , 2010 , Pages 1102-1105 ; 09608524 (ISSN) ; Vosoughi, M ; Ziaee, A. A ; Sharif University of Technology
2010
Abstract
A new dibenzothiophene (DBT) desulfurizing bacterium was isolated from oil-contaminated soils in Iran. HPLC analysis and PCR-based detection of the presence of the DBT desulfurization genes (dszA, dszB and dszC) indicate that this strain converts DBT to 2-hydroxybiphenyl (2-HBP) via the 4S pathway. The strain, identified as Rhodococcus erythropolis SHT87, can utilize DBT, dibenzothiophene sulfone, thiophene, 2-methylthiophene and dimethylsulfoxide as a sole sulfur source for growth at 30 °C. The maximum specific desulfurization activity of strain SHT87 resting cells in aqueous and biphasic organic-aqueous systems at 30 °C was determined to be 0.36 and 0.47 μmol 2-HBP min-1 (g dry cell)-1,...
Two schemes for production of biosurfactant from Pseudomonas aeruginosa MR01: Applying residues from soybean oil industry and silica sol–gel immobilized cells
, Article Colloids and Surfaces B: Biointerfaces ; Volume 152 , 2017 , Pages 159-168 ; 09277765 (ISSN) ; Ebadipour, N ; Roostaazad, R ; Partovi, M ; Bahmaei, M ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Rhamnolipids are the most common biosurfactants and P. aeruginosa strains are the most frequently studied microorganisms for the production of rhamnolipids. Eco-friendly advantages and promising applications of rhamnolipids in various industries are the major reasons for pursuing the economic production of these biosurfactants. This study shows that cultivation of P. aeruginosa MR01 in medium contained inexpensive soybean oil refinery wastes which exhibited similar levels and homologues of rhamnolipids. Mass spectrometry indicated that the Rha-C10-C10 and Rha-Rha-C10-C10 constitute the main rhamnolipids in different cultures of MR01 including one of oil carbon source analogues. Moreover,...
Accelerated full-thickness wound healing via sustained bFGF delivery based on a PVA/chitosan/gelatin hydrogel incorporating PCL microspheres
, Article International Journal of Pharmaceutics ; Volume 537, Issue 1-2 , 2018 , Pages 278-289 ; 03785173 (ISSN) ; Sarmadi, M ; Aghababaie, Z ; Vossoughi, M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Herein, a hybrid hydrogel/microsphere system is introduced for accelerated wound healing by sustained release of basic fibroblast growth factor (bFGF). The hydrogel is composed of a mixture of PVA, gelatin and chitosan. The double-emulsion-solvent-evaporation method was utilized to obtain microspheres composed of PCL, as the organic phase, and PVA, as the aqueous phase. Subsequently, various in-vitro and in-vivo assays were performed to characterize the system. BSA was used to optimize the release mechanism, and encapsulation efficiency in microspheres, where a combination of 3% (w/v) PCL and 1% (w/v) PVA was found to be the optimum microsphere sample. Incorporation of microspheres within...
Kinetics investigation of the photocatalytic degradation of acid blue 92 in aqueous solution using nanocrystalline TiO2 prepared in an ionic liquid
, Article Progress in Reaction Kinetics and Mechanism ; Volume 34, Issue 1 , 2009 , Pages 55-76 ; 14686783 (ISSN) ; Rahimnejad, S ; Rahman Setayesh, S ; Hosseini, M ; Gholami, M. R ; Sharif University of Technology
2009
Abstract
TiO2 nanoparticles were prepared by the sol - gel process using 2-hydroxylethy- lammonium formate as an ionic liquid. Nanoparticles were crystallized at various temperatures (300-700°C). The products were characterized using X-ray diffraction (XRD), nitrogen adsorption - desorption isotherms and scanning electron microscopy (SEM) techniques. It was found that the resulting TiO2 nanoparticles had good thermal stability either to resist collapse or the anatase-to-rutile phase transformation during heat treatment. The photocatalytic activity of the nanocrystalline TiO2 was evaluated by the degradation of Acid Blue 92 (AB92) which is commonly used as a textile dye. The results showed that the...
Synthesis of cellulose acetate/chitosan/SWCNT/Fe3O4/TiO2 composite nanofibers for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions
, Article International Journal of Biological Macromolecules ; Volume 140 , 2019 , Pages 1296-1304 ; 01418130 (ISSN) ; Koushkbaghi, S ; Pishnamazi, M ; Askari, A ; Khosravi, R ; Irani, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
The potential of electrospun cellulose acetate/chitosan/single walled carbon nanotubes/ferrite/titanium dioxide (CA/chitosan/SWCNT/Fe3O4/TiO2) nanofibers was investigated for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions via the adsorption and photocatalytic reduction processes. The properties of synthesized SWCNT/Fe3O4/TiO2 and fibers were characterized using TEM, SEM, FTIR, XRD, TGA and BET analysis. In adsorption process, the influence of adsorbent type including SWCNT to Fe3O4 ratio, TiO2 to SWCNT/Fe3O4 ratio and SWCNT/Fe3O4/TiO2 concentration as well as the adsorption parameters including pH, contact time, and initial concentration of adsorbates on...
Laser irradiation for controlling size of TiO2-Zeolite nanocomposite in removal of 2,4-dichlorophenoxyacetic acid herbicide
, Article Water Science and Technology ; Volume 80, Issue 5 , 2019 , Pages 864-873 ; 02731223 (ISSN) ; Borghei, S. M ; Moniri, E ; Kimiagar, S ; Panahi, H. A ; Sharif University of Technology
IWA Publishing
2019
Abstract
This study focused on the synthesis of TiO2-Zeolite nanocomposite through a sol-gel approach. The decrease in the size of the nanocomposite is considered a primary parameter to improve photocatalytic activity. In this regard, fabricated samples were exposed to laser irradiation (532 nm) for four different time intervals in order to investigate the size variation of the nanocomposite. FTIR, UV-Vis, XRD, DLS, SEM and EDX analyses were applied to characterize and determine the size of the products. An optimized nanocomposite sample, in term of the particle size, was used for photodegradation of 2,4-D herbicide from aqueous solution. Photodegradation was carried out under UV irradiation (12 W)...
A novel sol-gel-based amino-functionalized fiber for headspace solid-phase microextraction of phenol and chlorophenols from environmental samples
, Article Analytica Chimica Acta ; Volume 616, Issue 1 , 2008 , Pages 49-55 ; 00032670 (ISSN) ; Babanezhad, E ; Khalilian, F ; Sharif University of Technology
2008
Abstract
A novel amino-functionalized polymer was synthesized using 3-(trimethoxysilyl) propyl amine (TMSPA) as precursor and hydroxy-terminated polydimethylsiloxane (OH-PDMS) by sol-gel technology and coated on fused-silica fiber. The synthesis was designed in a way to impart polar moiety into the coating network. The scanning electron microscopy (SEM) images of this new coating showed the homogeneity and the porous surface structure of the film. The efficiency of new coating was investigated for headspace solid-phase microextraction (SPME) of some environmentally important chlorophenols from aqueous samples followed by gas chromatography-mass spectrometry (GC-MS) analysis. Effect of different...
Removal of bisphenol A in aqueous solution using magnetic cross-linked laccase aggregates from Trametes hirsuta
, Article Bioresource Technology ; Volume 306 , 2020 ; Ghobadi Nejad, Z ; Ghasemi, S ; Khafaji, M ; Borghei, S. M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Enzymatic removal of Bisphenol A (BPA), acknowledged as an environmentally friendly approach, is a promising method to deal with hard degradable contaminants. However, the application of “enzymatic treatment” has been limited due to lower operational stability and practical difficulties associated with recovery and recycling. Enzyme immobilization is an innovative approach which circumvents these drawbacks. In this study, laccase from Trametes hirsuta was used for BPA removal. Amino-functionalized magnetic Fe3O4 nanoparticles were synthesized via the co-precipitation method followed by surface modification with (3-aminopropyl)trimethoxysilane (APTMS). The as-prepared nanoparticles were...
Delafossite-alumina nanocomposite for enhanced catalytic wet peroxide oxidation of anionic pollutants
, Article Journal of Hazardous Materials ; Volume 417 , 2021 ; 03043894 (ISSN) ; Nouri, O ; Xie, Z ; Setayesh, S. R ; Wei, Z ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Mass transfer efficiency and catalytic reactivity are the two major hurdles for heterogeneous catalytic wet peroxide oxidation (CWPO) technologies. To address these issues, nanocomposite CuFeO2/Al2O3 was synthesized and assessed as a novel catalyst for enhanced adsorption and oxidation of anionic pollutants (catechol and reactive red 195 (RR195)) in waters. With a positive charge on the nanocomposite by introducing Al2O3, the adsorption of anionic pollutants was promoted. The surface complexation reaction on CuFeO2/Al2O3, which fits well to the Langmuir isotherm, has engined the mass transfer of pollutants to the nanocatalyst that demonstrated 96.46% and 99.75% removal of catechol and RR195...
Ethylenediamine-functionalized Zr-based MOF for efficient removal of heavy metal ions from water
, Article Chemosphere ; Volume 264 , 2021 ; 00456535 (ISSN) ; Tajahmadi, S ; Bahi, A ; Molavi, H ; Rezakazemi, M ; Ko, F ; Aminabhavi, T. M ; Arjmand, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Ethylenediamine-functionalized Zr-based metal-organic framework (MOF, UiO-66-EDA) was prepared via Michael addition reaction to investigate its potential for adsorption of heavy metal ions from water. Specifically, the influence of agitation time, solution pH, the dosage of the adsorbent, initial metal ion concentration, temperature, and coexistence of other metal ions was investigated on the removal efficiency of UiO-66-EDA towards Pb(II), Cd(II), and Cu(II) metal ions. The pseudo-second-order kinetic model governed the adsorption of these ions onto the UiO-66-EDA. Langmuir isotherm model matched the experimental isotherm of adsorption with a maximum adsorption capacity of 243.90, 217.39,...
Concurrent photocatalytic degradation and filtration with bi-plasmonic TiO2 for wastewater treatment
, Article Micro and Nano Letters ; Volume 16, Issue 3 , 2021 , Pages 194-202 ; 17500443 (ISSN) ; Amoli Diva, M ; Sadighi Bonabi, R ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
A new photocatalytic filtration membrane was prepared by grafting of Ag–Au bi-plasmonic shell-on TiO2@Fe3O4 nanoparticles as a magnetically-separable heterogeneous photocatalyst to a poly acrylic acid-modified cellulose acetate membrane for decomposition and removal of methyl orange as a model pollutant from textile wastewater samples. Eight photocatalysts including five Au NPs-modified TiO2@Fe3O4 NPs and three Ag-Au bi-plasmonic NPs-decorated TiO2@Fe3O4 NPs with different shell thickness were synthesized and characterized by TEM, UV–vis, and SEM techniques and their photocatalytic activity was assessed using two radiation sources. After selection of optimum photocatalyst and modification of...
Semi-empirical modelling of hydraulic conductivity of clayey soils exposed to deionized and saline environments
, Article Journal of Contaminant Hydrology ; Volume 249 , 2022 ; 01697722 (ISSN) ; Sadeghi, H ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Clay liners are widely used as porous membrane barriers to control solute transport and to prevent the leakage of leachate both in horizontal and vertical flow scenarios, such as the isolated base and ramps of sanitary landfills. Despite the primary importance of saturated hydraulic conductivity in a reliable simulation of fluid flow through clay barriers, there is no model to predict hydraulic conductivity of clayey soils permeated with saline aqueous solutions because most of the current models were developed for pure water. Therefore, the main motivation behind this study is to derive semi-empirical models for simulating the hydraulic conductivity of clayey soils in the presence of...
Thermo- and pH-sensitive dendrosomes as bi-phase drug delivery systems
, Article Nanomedicine: Nanotechnology, Biology, and Medicine ; Volume 9, Issue 8 , 2013 , Pages 1203-1213 ; 15499634 (ISSN) ; Fard, A. K ; Abedi, F ; Chegeni, B. K ; Bani, F ; Sharif University of Technology
2013
Abstract
Fully supramolecular dendrosomes (FSD) as bi-phase drug delivery systems are reported in this work. For preparation of FSD, amphiphilic linear-dendritic supramolecular systems (ALDSS) have been synthesized by host-guest interactions between hyperbranched polyglycerol having β-cyclodextrin core and bi-chain polycaprolactone (BPCL) with a fluorescine focal point. Self-assembly of ALDSS in aqueous solutions led to FSD. They were able to encapsulate paclitaxel with a high loading capacity. The dendrosome-based drug delivery systems were highly sensitive to pH and temperature. They were stable at 20-37. °C and pH7-8, but dissociated and released drug at temperatures lower than 20. °C or higher...
Design of pH-responsive nanoparticles of terpolymer of poly(methacrylic acid), polysorbate 80 and starch for delivery of doxorubicin
, Article Colloids and Surfaces B: Biointerfaces ; Volume 101 , January , 2013 , Pages 405-413 ; 09277765 (ISSN) ; Chan, H. K ; Raval, G ; Abdekhodaie, M. J ; Liu, Q ; Heerklotz, H ; Wu, X. Y ; Sharif University of Technology
2013
Abstract
This work focused on the design of new pH-responsive nanoparticles for controlled delivery of anticancer drug doxorubicin (Dox). Nanoparticles of poly(methacrylic acid)-polysorbate 80-grafted starch (PMAA-PS 80-g-St) were synthesized by using a one-pot method that enabled simultaneous grafting of PMAA and PS 80 onto starch and nanoparticle formation in an aqueous medium. The particles were characterized by FTIR, 1H NMR, TEM, DLS, and potentiometric titration. Dox loading and in vitro release from the nanoparticles were investigated. The FTIR and 1H NMR confirmed the chemical composition of the graft terpolymer. The nanoparticles were relatively spherical with narrow size distribution and...
Novel polyamide-based nanofibers prepared by electrospinning technique for headspace solid-phase microextraction of phenol and chlorophenols from environmental samples
, Article Analytica Chimica Acta ; Volume 716 , 2012 , Pages 34-39 ; 00032670 (ISSN) ; Aghakhani, A ; Baghernejad, M ; Akbarinejad, A ; Sharif University of Technology
2012
Abstract
A novel solid phase microextraction (SPME) fiber was fabricated by electrospinning method in which a polymeric solution was converted to nanofibers using high voltages. A thin stainless steel wire was coated by the network of polymeric nanofibers. The polymeric nanofiber coating on the wire was mechanically stable due to the fine and continuous nanofibers formation around the wire with a three dimensional structure. Polyamide (nylon 6), due to its suitable characteristics was used to prepare the unbreakable SPME nanofiber. The scanning electron microscopy (SEM) images of this new coating showed a diameter range of 100-200nm for polyamide nanofibers with a homogeneous and porous surface...
Assembly of CeO 2-TiO 2 nanoparticles prepared in room temperature ionic liquid on graphene nanosheets for photocatalytic degradation of pollutants
, Article Journal of Hazardous Materials ; Volume 199-200 , 2012 , Pages 170-178 ; 03043894 (ISSN) ; Setayesh, S. R ; Habibi Yangjeh, A ; Hormozi Nezhad, M. R ; Gholami, M. R ; Sharif University of Technology
2012
Abstract
CeO 2-TiO 2 nanoparticles were prepared by the sol-gel process using 2-hydroxylethylammonium formate as room-temperature ionic liquid and calcined at different temperatures (500-700°C). CeO 2-TiO 2-graphene nanocomposites were prepared by hydrothermal reaction of graphene oxide with CeO 2-TiO 2 nanoparticles in aqueous solution of ethanol. The photocatalysts were characterized by X-ray diffraction, BET surface area, diffuse reflectance spectroscopy, scanning electron microscopy, and Fourier transformed infrared techniques. The results demonstrate that the room-temperature ionic liquid inhibits the anatase-rutile phase transformation. This effect was promoted by addition of CeO 2 to TiO 2....