Mohammadreza omidkhah | Tarbiat Modares University (original) (raw)

Papers by Mohammadreza omidkhah

In Part I a decomposition was suggested which allowed different process structures to be screened... more In Part I a decomposition was suggested which allowed different process structures to be screened for processes not involving selectivity losses without having to search the whole solution space. We have been extended to processes having selectivity losses in the reactor. It has been found that the decomposition is still valid with selectivity losses, providing the alternative structures being compared have the same conversion versus selectivity relationship

علوم و تکنولوژی پلیمر, 2017

Asymmetrically mixed matrix Matrimid-MIL-53 membranes with silicone cover layer were fabricated. ... more Asymmetrically mixed matrix Matrimid-MIL-53 membranes with silicone cover layer were fabricated. For better understanding of membrane fabrication process, three main parameters of fabrication, Matrimid concentration, silicone concentration and weight percentage of metal organic framework (MIL-53) particles, were optimized by an experimental design method. Cross-section SEM images were used to study the membrane structure and polymer-particles interface. Moreover, thermal resistance of the membranes and the existence of various bonds in them were investigated by FTIR and TGA analyses. The results showed that membranes had porous structure with finger-like morphology. At low and moderate percentages of particles, there were no non-selective voids observed at polymer-particles interface. The thermal resistance of membranes increased with the increase of MIL-53 weight percentage and the destruction temperature of polymer increased from 410°C to 450°C. The permeability tests results show...

Journal of Environmental Management, Dec 1, 2020

This work investigates the performance and structure of polyamide thin film nanocomposite (PA-TFN... more This work investigates the performance and structure of polyamide thin film nanocomposite (PA-TFN) membrane incorporated with triethylenetetramine-modified graphene oxide (GO-TETA). The embedment of GO-TETA nanosheets within the structure of PA-TFN membrane was evaluated at different concentrations (0.005, 0.01, 0.03 wt%; in aqueous piperazine (PIP)) through interfacial polymerization (IP). The physicochemical properties of the prepared membrane were investigated by SEM, AFM, water contact angle, and zeta potential as well as ATR-IR spectroscopy. The presence of longer chains of amino groups (in comparison with the directly linked amino ones) among the stacked GO nanosheets was assumed to increase interlayer spacing, resulting in remarkable changes in water permeance and separation behavior of modified polyamide (PA) membrane. It is seen that GO-TETA nanosheets were uniformly distributed in the matrix of PA layer. With increasing the concentration of GO-TETA, the flux of TFN membranes under 6 bar was increased from 49.8 l/m 2 h (no additive) to 73.2 l/m 2 h (TFN comprising 0.03 wt% GO-TETA. In addition, more loading GO-TETA resulted in a significant decrease in the average thickness of the polyamide layer from ~380 to ~150 nm. Furthermore, addition of GO-TETA improved the hydrophilicity of nanocomposite membranes, resulting in superb water flux recovery (antifouling indicator) as high as 95% after filtration of bovine serum albumin solution. Also, the retention capability of the TFN membranes towards some textile dyes increased as high as 99.6%.

A series of γ-alumina-supported cobalt-molybdenum mesoporous catalysts have been provided with va... more A series of γ-alumina-supported cobalt-molybdenum mesoporous catalysts have been provided with various ratios of Co/Mo (0.0, 0.1, 0.3 and 0.5). Cobalt and molybdenum were loaded on a support via an incipient wetness impregnation method. Samples of the catalysts were characterized using XRD, BET and BJH. Then Oxidative desulfurization (ODS) of Benzothiophene (BT) and Dibenzothiophene (DBT) with H 2 O 2 as oxidant was studied. The catalyst with Co/Mo mole ratio 0.1 and Cat/oil ratio 0.03 (g/mL) showed high performance to oxidation of BT and DBT, which has led to about 19% conversion increase for BT and 17% of DBT comparing catalysts without cobalt (Co/Mo 0.0). The various sulfur compounds reactivity was studied which followed the order of DBT >>BT.

Ceramics International, Jul 1, 2023

Journal of Molecular Liquids, Sep 1, 2022

Journal of The Iranian Chemical Society, Jan 3, 2019

This study indicates the importance of statistical analysis and modeling to investigate the synth... more This study indicates the importance of statistical analysis and modeling to investigate the synthesis and optimization of anodized aluminium oxide (AAO) properties for template-assisted synthesis of nanostructure particles. The response surface methodology was used to optimize pore size and porosity of AAO. The impacts of four main parameters including type of acidic electrolyte, concentration of acid, bath temperature and electrical potential of anodization on characterization of AAO were investigated. Statistical analysis showed that the linear and quadratic terms of these variables had significant effects. Based on the statistical analysis, a possible mechanism of the anodization was proposed. The proposed mechanism helped us to develop an analytical model. The analytical model could predict the experimental results with an appropriate accuracy. Results indicated the rate-limiting reaction in anodization process is water dissociation which was conducted at the pore bottom of the AAO. In addition, concentrated electrical field at pore base induced water splitting so that the activation energy of water dissociation decreased ten times and reached to 9898.5 J mol .

ACS Applied Materials & Interfaces, May 7, 2018

Fluid Phase Equilibria, 2010

Accurate representation of the thermodynamic properties of pure compounds is required to increase... more Accurate representation of the thermodynamic properties of pure compounds is required to increase the robustness of an equation of state (EOS) when predicting phase equilibria for mixtures. With this purpose, 23 generalized equations of state (EOSs) have been applied to predict the thermodynamic properties of 102 pure substances (16,107 data points) and to report the average absolute deviations of these

Oily wastewaters pose significant environmental challenges, requiring effective treatment methods... more Oily wastewaters pose significant environmental challenges, requiring effective treatment methods for sustainable development. This study investigates the potential of combining filtration, electrofiltration, and backwashing using a ceramic membrane for the treatment of oily water. A secondary mullite membrane is synthesized, demonstrating favorable characteristics such as high permeate flux (534 LMH), biaxial flexural strength (75.21 MPa), and cost-effectiveness. Experimental investigations were performed for operational parameters, resulting in the selection of a pressure of 2 bar and a cross-flow velocity of 0.727 m/s to achieve desirable permeate flux and oil removal rates. The critical electric field intensity (Ecrit) is determined experimentally and theoretically, ranging from 50 to 55 V, guiding the selection of optimal voltages for electrofiltration. Electrokinetic phenomena, including electrophoresis, electroosmosis, and bubble formation, are harnessed to mitigate fouling. ...

Journal of Cleaner Production

Chemical Papers, 2020

In present study, new visible driven photocatalysts (TiO 2 /4-CNT/20-BiOBr/10-Bi 2 S 3) with vari... more In present study, new visible driven photocatalysts (TiO 2 /4-CNT/20-BiOBr/10-Bi 2 S 3) with various loading of CNT (2, 4, 6 and 8 wt%), (10, 20, 30 and 40 wt%) and Bi 2 S 3 (5, 10, 15 and 20 wt%) were successfully synthesized and characterized by XRD, FTIR, FESEM, PL, and DRS analysis. The DRS and PL analysis confirmed a redshift of modified TiO 2 into a visible light range and the reduction of the recombination rate of electron/hole. The photodegradation results showed the optimum weight percentage of CNT, BiOBr, and Bi 2 S 3 was 4%, 20%, and 10% respectively. Besides, the central composite design (CCD) was applied to model and optimize the photocatalytic activity of nanocatalyst for photodegradation of reactive blue 19 (RB19) and assess the effects of four independent variables including RB19 concentration, catalyst concentration, pH, and irradiation time on the response. The photocatalytic activity performance of TiO 2 /4-CNT/20-BiOBr/10-Bi 2 S 3 under visible light irradiation for RB19 removal showed that 97.2% dye removal efficiency was obtained at optimum conditions of pH 4, catalyst dosage 1 g/L, RB19 concentration 50 mg/L, and contact time 60 min. The investigation of the effect of processing factors on the dye removal efficiency confirmed that increasing the catalyst concentration and time while decreasing pH and dye concentration resulted in the dye removal efficiency in a short time. The reusability of the catalyst was studied under optimum conditions ([RB19] = 50 mg/L, [TiO 2 /4-CNT/20-BiOBr/10-Bi 2 S 3 ] = 1 g/L, pH = 4 and irradiation time = 60 min).

Journal of Industrial and Engineering Chemistry, 2019

Abstract This study focuses on the modification of commercial polyvinylidene fluoride (PVDF) memb... more Abstract This study focuses on the modification of commercial polyvinylidene fluoride (PVDF) membranes using surface-initiated atom transfer radical polymerization (SI-ATRP) method. Poly(N-isopropylacrylamide) (PNIPAAm) was grafted from PVDF surface and then PEGMA was grafted onto the PVDF-g-PNIPAAm membrane. The aim of the research was to prepare membranes that simultaneously have antifouling and self-cleaning properties. PNIPAAm (lower block) was grafted to give the membrane temperature sensitive property and PPEGMA (upper block) was used to improve hydrophilicity. Morphology, topography and chemical composition of the modified membranes were completely characterized. Antifouling and cleaning ability of modified membranes were investigated using synthetic oily water. Moreover, the role of PEGMA polymerization time on the membrane performance was examined. PNIPAAm-b-PPEGMA modified membrane achieved 64% decrease in fouling ratio compared to unmodified PVDF membrane at best condition. The flux recovery was 99.1% for modified membrane at this condition. Furthermore, the unmodified PVDF membrane showed 91.1% oil rejection; while the modified membrane could reject 98.2% oil molecules. The final flux of all modified membranes were higher than unmodified membrane. These results indicated that PNIPAAm-b-PPEGMA modified membranes have excellent fouling resistance and self-cleaning ability.

Journal of Membrane Science, 2018

In this work, poly[1-vinyl-3(2-carboxyethyl) imidazolium betaine] (PVCIB), as a zwitterionic poly... more In this work, poly[1-vinyl-3(2-carboxyethyl) imidazolium betaine] (PVCIB), as a zwitterionic polyelectrolyte, was tethered onto a commercial thin film composite polyamide (TFC PA) membrane. First, polyvinyl imidazole (PVI) was grafted onto the TFC PA membrane surface by free radical graft polymerization method at various grafting times. Afterwards, one of PVImodified membranes was betainised using 3-bromopropionic acid to obtain PVCIB brushes on the membrane surface. Evaluation of membrane performance through desalination process indicated that despite decrease of salt rejection, water flux increased from 73.4 L/m 2 .h in the PA membrane to 91.6 L/m 2 .h in the PA-PVCIB membrane. Antimicrobial assessment using Escherichia coli showed that PVCIB-modified membrane was able to inhibit bacterial growth by about 98.8%. Antifouling and cleaning abilities of membranes were investigated using BSA and lysozyme at various pH values. It was revealed that hydrophilic PVCIB brushes considerably improved protein-resistant property of the TFC PA membrane. However, considering pHdependent behavior of PVCIB (zwitterionic at alkaline pH or polyelectrolyte at acidic pH), hydration repulsion or electrostatic repulsive forces, respectively, made a contribution to fouling mitigation. Accordingly, PA-PVCIB membrane exhibited remarkable antifouling ability to resist non-specific protein adsorption at neutral and alkaline pHs, whereas both PA-PVI and PA-PVCIB membranes exhibited marked resistance to the positively charged lysozyme adhesion at acidic pH.

Zeitschrift für anorganische und allgemeine Chemie, 2018

The sensitivity of an energetic compound gives its vulnerability to accidental detonation, which ... more The sensitivity of an energetic compound gives its vulnerability to accidental detonation, which is caused by an unintended stimulus. Shock and electric spark sensitivities of energetic compounds are two important sensitivity parameters for assessment of their safety in working places. Several correlations are introduced for reliable prediction of shock sensitivities of energetic compounds at 90, 95, and 98 % of theoretical maximum density (TMD) according to NSWC using Navy small-scale gap test through their electric spark sensitivities. For 11 explosives, where experimental data of both shock and electric spark sensitivities were available, the predicted results at 90 % of TMD

Zeitschrift für anorganische und allgemeine Chemie, 2017

Electric spark sensitivity and shock sensitivity based small-scale gap test for nitramine energet... more Electric spark sensitivity and shock sensitivity based small-scale gap test for nitramine energetic compounds are two important sensitivity parameters, which are needed for assessment of their safety in working places. A novel method is introduced for reliable prediction of electric spark or shock sensitivity of a desired nitramine energetic compound when reliable data for one of the sensitivity is available. A novel correlation with a high value of correlation coefficient (R 2 =0.998) is derived between electric spark and shock sensitivities of 20 cyclic and acyclic nitramines. For these nitramines, the predicted results of electric spark sensitivities of the novel model are compared with two of the best available models. The root-mean-square (rms) and maximum deviations of the new model are 0.20 and 0.51 J, respectively, which are much less than two comparative methods. The reliability of the new method for prediction of electric spark sensitivity of further 14 nitramines is also compared with one of the best available methods, where the measured electric spark or shock sensitivities were not available in literature.