Mahdi Pourafshari Chenar

Mahdi Pourafshari Chenar
Ferdowsi University Of Mashhad | FUM · Department of Chemical Engineering

Professor

About

83
Publications
25,152
Reads
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1,455
Citations
Citations since 2017
39 Research Items
1071 Citations
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
Additional affiliations
January 2014 - present
Ferdowsi University Of Mashhad
Position
  • Head of Department

Publications

Publications (83)
Article
Pervaporation (PV) process with the mixed matrix membrane (MMM) is a feasible and cost-effective alternative to conventional volatile organic compounds (VOC) removal methods. In this study, the mesoporous silicate MCM-41 was synthesized by a new and rapid sol-gel method and incorporated into the polyether-block-amide (PEBA-2533) polymer network. Pr...
Article
Porous flat sheet membranes were prepared with a commercial grade of cyclic olefin polymer (COP) for CO2 capture using membrane contactor (MC). The membranes were prepared via non-solvent induced phase separation technique using different types of additives, namely, polyvinylpyrrolidone (PVP), polyethylene glycol (PEG400) and sorbitan monooleate (S...
Conference Paper
Full-text available
One of the desired processes to upgrade conventional activated sludge and effluent quality is Integrated Fixed-film Activated Sludge (IFAS) process. One of the important operational parameters in this process is nitrification control and ammonia removal. Therefore, the process was simulated using GPS-X software. In this simulation, it was assumed t...
Article
In this work, layer by layer (LbL) thin film nanocomposite (TFN) membranes were prepared and used as pervaporation membranes to separate methyl tertiary butyl ether (MTBE)/methanol (MeOH) mixture. TFN membranes, comprising of carbon nanotubes (CNT), were prepared by interfacial polymerization (IP) of m-phenylenediamine (MPD) and trimesoyl chloride...
Conference Paper
Decrease of the cost of water treatment at no detriment of its water quality is a goal-directed objective in the SWRO1 market, which plays a determining role in the success of a bid in a tender. Therefore, a cleaver design to fulfill the market requirements is of practical interest. Herein, using WAVE software (DuPont), a reverse osmosis desalinati...
Article
A first attempt was made to prepare cyclic olefin polymer/copolymer (COP/COC) flat-sheet porous membranes by the well-known non-solvent induced phase separation method. In this study, two solvents (chloroform and 1,2,4-trichlorobenzene), different additives (polyvinylpyrrolidone, PVP, polyethylene glycol, PEG400, polyethylene oxide, PEO, and Sorbit...
Article
The effect of methanol group on absorption of SO2 by diamine compound was investigated via density functional theory. It was observed that the presence of methanol group increases the binding energy of absorption. According to the result of binding energy, the di-methanol-diamine (D-b) structure can be the best diamine for SO2 absorption and the re...
Conference Paper
Full-text available
The A2O process is one of the conventional processes used for nutrient and BOD removal. This process is associated with issues such as high sludge production and low SRT during operation. Also, wastewater treatment plants (WWTP) overloading forces operators to produce more sludge in order to meet effluent quality standards. In this paper, enhancing...
Conference Paper
Full-text available
The A2O process is one of the conventional processes used for nutrient and BOD removal. This process is associated with issues such as high sludge production and low SRT during operation. Also, wastewater treatment plants (WWTP) overloading forces operators to produce more sludge in order to meet effluent quality standards. In this paper, enhancing...
Article
Full-text available
The current experimental and theoretical study proposes a forward osmosis (FO)-reverse osmosis (RO) (FR*) and FO-FO-RO (FFR) hybrid systems to combine concentration of cheese whey and Caspian seawater desalination. The concentrated cheese whey in the first FO unit is collected and sold as a valuable by-product to reduce the cost of Caspian seawater...
Article
Full-text available
In this study, a facile and efficient approach to increase the magnetic property of metal-organic framework-5 (MOF-5) has been investigated. The basis of this approach is the encapsulation of cluster-oxygen composition (i.e. ZnO in MOF-5) during the synthesis process of MOF-5 to form ZnO@MOF-5 nanocrystals. Both MOF-5 and ZnO@MOF-5 were synthesized...
Article
In this study, the effect of solvent type and nanoparticles of silica and zeolite 4A on the gas separation properties of polyimide (PI) membranes were investigated. Gas separation of the membranes based on pure solvents of dimethylformamide (DMF), n‐methyl‐2‐pirrolidone (NMP), dimethylacetamide (DMAc), and dimethylsulfoxide (DMSO) were studied. The...
Article
Full-text available
The main reason for the lower water flux, than expected, in the forward osmosis (FO) process, is the internal concentration polarization (DICP). Usually, the structural parameter (S) is used as an indicator of the intensity of DICP. Small S value is desirable for the FO membrane due to the low DICP. However, due to design and construction problems,...
Conference Paper
Full-text available
One of the desired processes to upgrade conventional activated sludge and effluent quality is Integrated Fixed-film Activated Sludge (IFAS) process. One of the important operational parameters in this process is nitrification control and ammonia removal. Therefore, the process was simulated using GPS-X software. In this simulation, it was assumed t...
Article
Enhancing the performance of gas separation membranes is one of the major concerns of membrane researchers. Thus, in this study, poly(ether‐block‐amide) (Pebax)/polyetherimide (PEI) thin‐film composite membranes were prepared and their CO2/CH4 gas separation performance was investigated by means of pure and mixed gases permeation tests. To improve...
Article
Physical modification of support layers (SLs) for thin‐film composite (TFC) forward osmosis (FO) membranes is the main goal of this study. Accordingly, the strategy of metal–organic framework (MOF)‐based porous matrix membrane (PMM) was used for the fabrication of controllable SLs. Fourteen different TFC FO membranes were successfully fabricated by...
Article
Full-text available
Physical modification of support layers (SLs) for thin-film composite (TFC) forward osmosis (FO) membranes is the main goal of this study. Accordingly, the strategy of metal-organic framework (MOF)-based porous matrix membrane (PMM) will be used for the fabrication of controllable SLs. Fourteen different TFC FO membranes were successfully fabricate...
Article
The current study focused on the preparation of adsorptive nanocomposite membrane for Cu(II) removal from aqueous solution. TiO2 nanoparticles as adsorbent and Polyaniline (PANi) as a modifier to improve dispersion quality and adsorption capacity of TiO2, were added to the polyethersulfone (PES) casting solution. Adsorptive membranes were prepared...
Article
Herein, to meet the requirement of the stringent sulfur emission and discharge rate standards based on World Health Organization (WHO) and Environmental Protection Agency (EPA), polyamide/titanium dioxide (PA/TiO 2 ) thin film nanocomposite (TFN) membranes were synthesized to remove sulfur compound from sulfur recovery unit (SRU) wastewater. The ex...
Article
In this study, polysulfone/wood sawdust (PSf/WSD) mixed matrix membrane (MMM) was prepared as a novel substrate layer of thin‐film composite (TFC) membrane in water desalination. The main aim was to evaluate how different amounts of WSD (0‐5 wt%) and PSf concentrations (12‐16 wt%) in the porous substrate affect the properties of the final TFC membr...
Article
Full-text available
In this study, we explore the use of hydrophobic (ZIF-8) and hydrophilic (UiO-66) water-stable metal-organic-framework (MOF), as well as their mixture for the fabrication of high performances mixed-matrix membrane (MMM)-based thin film composite (TFC) forward osmosis (FO) membranes for controlling internal concentration polarization (ICP). Accordin...
Article
Full-text available
Herein, the influence of pure and modified polyvinyl chloride (PVC) support layers on the performance of thin-film composite (TFC) membranes was investigated in water desalination. Accordingly, the PVC support was modified using (3-Aminopropyl) triethoxysilane (APTES) through bulk modification. The supports were synthesized at different doses of AP...
Article
Full-text available
The fabrication methods of FO membranes are always ready for a revolution. Here we present an efficient strategy to fabricate a novel integral thin-film based porous matrix membrane (TF-PMM). The goal of this study is to fabricate a TF-PMM by modifying conventional dense film casting method, using magnetic water-unstable MOFs as pore former. The MO...
Article
A comprehensive study was performed on a new application of thin film composite membranes and selecting a stable sublayer for them as pervaporation membranes in organic solvent separation. For this purpose, four different polymeric sublayers of polyethersulfone (PES), cellulose acetate, polyacrylonitrile, and polyetherimide were prepared, and the i...
Article
Full-text available
In this work, a new strategy to increase the stability of humid-unstable MOFs in humid environment has been investigated. Among many known humid-unstable MOFs, MOF-5 has been selected due to its unique properties. The present work quantifies the influence of exposure to humid environment on the properties of MOF-5 as a function of relative humidity...
Poster
Full-text available
has been investigated to improve activated sludge treatment plant to MBBR by simulation in the environment of GPS-X .
Article
Full-text available
Density Functional Theory (DFT) calculations techniques in terms of energetic and electronics properties are used to study CO2 adsorption in NH2-, OH-, COOH-, Br- and Cl-functionalized IRMOF-1. Geometry optimization, density of states (DOS), and energy analysis were performed to investigate the adsorption phenomenon. First, we examined the geometri...
Article
Full-text available
To investigate the adsorption property of H2 and CO2 on the organic ligand of C-MOF-5 (H2BDC) and T-MOF-5 (ZnO-doped H2BDC (ZnO-H2BDC)), Density functional theory (DFT) method was performed. First, the adsorption of ZnO on H2BDC resulted in examining binding energies, the charge transfer, density of states, dipole moments and adsorption geometries...
Article
The influence of amino-grafted nano-silica particles on the CO2/light gases separation performance of Matrimid mixed matrix membrane was evaluated. The aminosilane grafting reaction was performed using (3-aminopropyl) terimethoxysilane (APTMOS) as a silane coupling agent. Prepared membranes were studied through various methods including FTIR, SEM a...
Article
The disposal of polymeric and hazardous materials is an important global issue. Thus, the mechanochemical reclaiming of waste EPDM rubber was carried out using disulfide oil (DSO), oily waste produced in gas refineries, as a reclaiming agent at a specific operation condition. Reclaimed rubber was characterized by crosslink density, sol-gel, and Moo...
Article
PES/Pebax and PEI/Pebax composite membranes were prepared by coating the porous PES and PEI substrate membranes with Pebax-1657. The morphology and performance of the prepared membranes were investigated by SEM and CO2 and CH4 permeation tests. The CO2 permeances of 28 and 52 GPU were achieved for PES/Pebax and PEI/Pebax composite membranes, respec...
Article
In this study, a new application for used reverse osmosis (RO) membranes as gas separation membranes was studied. In this regard, firstly, three pretreatment procedures were used to remove the foulants from the surface of used membrane and then they were coated with polydimethylsiloxane (PDMS). The results indicated that PDMS-coated used RO membran...
Article
Full-text available
In this study, the effects of silica nanoparticles on the permeability of pure CO2, O2, and N2 gases in cellulose acetate (CA) membrane have been studied. Silica particles were prepared via the sol-gel method through the hydrolysis of tetraethyl orthosilicate (TEOS). CA and CA/silica nanocomposite membranes were prepared by thermal phase inversion...
Article
The aim of this study was to investigate the potential of micellar–enhanced ultrafiltration (MEUF) process in the removal of free active chlorine (FAC) from synthetic wastewater using polyethersulfone/titania (PES/TiO2) nanocomposite membrane. To achieve this objective, investigation was done in terms of stable permeate flux (SPF) and hypochlorite...
Article
Thin film composite (TFC) reverse osmosis (RO) membranes are semipermeable membranes that are utilized in water purification or water desalination systems. Discarding these membranes after end-of-life leads to environmental problems. Reusing old TFC-RO membranes is one way to solve this problem. For this reason, in this study, used TFC-RO membranes...
Article
Full-text available
Adsorption of arsenic (III, V) from aqueous solution onto the synthesized α-Fe2O3/MCM-41 nanocomposite adsorbent, as function of contact time, initial concentration of the solution, temperature, pH, and presence of other anionic species, has been investigated. Characterization of adsorbent was performed via XRD, FT-IR, TGA, TEM, and N2 adsorption–d...
Article
In the present research, novel polyether block amide (PEBA)/polyvinyldene fluoride (PVDF) blend pervaporation (PV) membranes were prepared for the removal of isopropyl alcohol (IPA) from the aqueous solution. The membranes obtained at PEBA/PVDF ratios of 100/0, 95/5, and 90/10 were characterized using scanning electron microscopy, thermogravimetric...
Article
The structural properties and gas permeation of a group of copolyimide membranes were investigated. The copolyimides used in this study were prepared using 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and 4,4′-oxydianyline (ODA) as aromatic diaminens and 4,9-dioxa-1,12-dodecanediamine (DODD), 1,13-diamino-4,7,10-trioxatridecane (TODD) a...
Article
The disposal of polymeric and especially rubber materials is an important global issue. In this work we have used disulfide oil (DSO), the oily waste produced in gas refineries, as a chemical agent for mechanochemical reclaiming of waste EPDM rubber at a specific operation condition. The devulcanization reaction was performed using different concen...
Article
This study seeks to address the influence of critical variables including casting thickness, polysulfone (PSf) concentration, m-phenylenediamine soaking time, curing time, curing temperature and interfacial polymerization (IP) time in the preparation of thin film composite (TFC) membrane. To properly track the effects of each parameter as well as t...
Article
Chemical devulcanization of sulfur cured natural rubber (NR) was investigated using benzoyl peroxide (BPO) as a devulcanizing agent. The influence of important reclaiming parameters such as reaction time, reaction temperature and concentration of the devulcanizing agent on the devulcanization process and mechanical properties of the resulting produ...
Article
In this study, a new approach to improve antifouling performance of polyacrylonitrile (PAN) hollow fiber membrane has been explained. Firstly, chemical modification with sodium hydroxide (NaOH) solution was performed on PAN membranes in various conditions, so that, as a result of hydrolysis, carboxyl groups emerge on membrane surface. Then, in orde...
Article
Full-text available
In this study, a new method was applied to achieve an efficient surface modification of Polyacrylonitrile (PAN) hollow fiber membrane. The surface modification dealt by immersion of PAN hollow fibers in hydroxylamine solution under various conditions (different solution concentrations and reaction time). The nitrile groups on the surface of the mem...
Article
The aim of this study was to investigate the performance of single and mixed surfactants, both non-ionic and anionic, for the removal of nickel from aqueous solution using micellar-enhanced ultrafiltration (MEUF). To achieve this objective, SDS and four non-ionic surfactants with different ethylene oxide (EO) group length were utilized in this work...
Article
An economic assessment of natural gas dehydration using polymeric membranes was made through modeling and simulation and the results were compared with those conducted through absorption and adsorption. A diagram of the economic boundaries between different natural gas dehydration processes was also introduced. The effects of the membrane propertie...
Conference Paper
Full-text available
Biological fouling (bio-fouling) is one the main troubles in water desalination and wastewater treatment by membrane processes. In the present study, bio-fouling control approach by surface modification of thin film composite (TFC) membrane with nanosilver coating has been investigated. In order to determine the effectiveness of nanosilver coating,...
Article
Micellar-enhanced ultrafiltration (MEUF) is a promising method to remove low molecular weight (LMW) organic contaminants from water. In this work, a series of experiments were conducted in order to evaluate the efficiency of an MEUF process for the removal of aniline (as LMW organic contamination) using a 1 kDa molecular weight cut-off polyethersul...
Article
Full-text available
Researchers have focused on improving the performance of polymeric membranes through various methods, such as adding inorganic nanoparticles into the matrix of the membranes. In the present study, the separation of oxygen, nitrogen, methane and carbon dioxide gases by PVC/silica nanocomposite membranes was investigated. Silica nano-particles were p...
Article
The aim of this study was to evaluate the performance of the micellar-enhanced ultrafiltration (MEUF) process for the simultaneous removal of aniline and nickel from the aqueous phase. A prepared polysulfone (PSf) membrane and two commercially available membranes (NP010 and UFX5) were used to investigate the effects of the molecular weight cut-off...
Article
Full-text available
In this study, the effects of various solvents on the structure and permeation properties of polysulfone–silica nanocomposite membranes were investigated. Silica nanoparticles were prepared by the sol–gel method through the hydrolysis and condensation of tetraethyl orthosilicate (TEOS). Polysulfone–silica nanocomposite membranes were prepared by th...
Article
Full-text available
The effects of preparation parameters on the performance and morphology of polydimethylsiloxane/ polysulfone (PDMS/PSf) membranes were investigated. The PDMS layer is mainly used for sealing the defects of the PSf selective layer. The membrane morphologies were characterized by using scanning electron microscopy (SEM). The CO2/CH4 separation perfor...
Article
The separation of olefin–paraffin mixtures is one of the most important and expensive processes in petrochemical industries. In this research, the performance of cellulose acetate–silica nanocomposite membranes in the separation of ethylene/ethane and propylene/propane has been studied. Silica nanoparticles were prepared via hydrolysis of tetraetho...
Article
In this study, the effect of the structure of polyether-based polyurethane (PU) membranes on their gas separation properties has been investigated. In this regard, a series of polyurethanes based on hexamethylene diisocyanate (HDI) and 1,4-butanediol as hard segments and different soft segments such as poly(tetramethylene glycol) (PTMG, 2000 g/mol)...
Article
Full-text available
In this study, the critical micellar concentration (CMC) of anionic, cationic and nonionic surfactants was determined using the UV–Vis spectroscopic method. Sodium lauryl sulfate (SDS) as anionic, hexadecyl-trimethyl-ammonium bromide as cationic, tert-octylphenol ethoxylates TOPEON (with N = 9.5, 7.5 and 35) and lauryl alcohol ethoxylate (23EO) as...
Article
In a modern day sulfur recovery unit (SRU), hydrogen sulfide (H2S) is converted to elemental sulfur using a modified Claus unit. A process simulator called TSWEET has been used to consider the Claus process. The effect of the H2S concentration, the H2S/CO2 ratio, the input air flow rate, the acid gas flow of the acid gas (AG) splitter and the tempe...
Article
a b s t r a c t In this study, the effect of silica nanoparticles on the gas permeation properties of polyether-based polyurethane membrane was investigated. Polyether-based polyurethane was synthesized by bulk two-step polymerization of polypropylene glycol/hexamethylenediisocyanate (HMDI)/1,4-butanediol (BDO) in mole ratios of 1:3:2. Silica nanop...
Article
SBA-15 nanoparticles were prepared by in situ assembly of inorganic precursors and CTAB. The structure of nanoparticles was characterized by X-ray diffraction, transmission electron microscopy, particle size analysis, and N 2 adsorption techniques. The surface modification of particles in order to perfect dispersion in PSF matrix was performed by D...
Article
In this sulfur recovery unit (SRU), hydrogen sulfide (H 2 S) is converted to elemental sulfur using modified sulfur recovery unit. In the present study, first the simulation of Claus process has been considered using a process simulator called TSWEET then the effect of H 2 S concentration, H 2 S/CO 2 ratio and acid gas flow of AG splitter in three...
Article
In this study the effects of water/solvent mixture as coagulation medium with different solvent content, coagulation bath temperature (CBT) and coagulant type on the performance, morphology and thermal stability of polysulfone membranes were investigated. SEM and TGA techniques were used to characterize the fabricated membranes. Based on the obtain...
Article
In this study, the effect of film preparation conditions on the gas permeation properties of polyethylene (PE) and ethylene vinyl acetate (EVA) films (containing 18 & 28 wt% vinyl acetate) was investigated. Film blowing and phase inversion methods were applied to produce PE and EVA films, respectively. The permeation of pure oxygen and carbon dioxi...
Article
In this study, the effect of film preparation conditions on the gas permeation properties of polyethylene (PE) and ethylene vinyl acetate (EVA) films (containing 18 and 28wt% vinyl acetate) was investigated. Film blowing and phase inversion methods were applied in the production of PE and EVA films, respectively. The permeation of pure oxygen and c...
Article
Full-text available
Impurities such as hydrogen sulfide, water vapor and heavy hydrocarbons in natural gas have considerable effects on the membrane performance. Small amounts of condensable and polymer soluble components in the feed gas cause swelling or plasticization of glassy membranes, leading to a reduction in membrane selectivity. In the present research the in...
Article
Full-text available
The performance of commercially available poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) and Cardotype polyimide (PI) hollow fiber membranes was investigated in removing hydrogen sulfide from methane in a series of bench-scale experiments. It was observed that in the concentration range of hydrogen sulfide in methane from 101 to 401 ppm, the methane...
Article
In this study, a two-stage membrane system for the separation of CH4/CO2 was designed based on a series of laboratory-scale experiments obtained using two types of commercial hollow fiber membranes including polyphenylene oxide (PPO) and Cardo-type polyimide (PI). The former showed high permeability and low to moderate selectivity, while the latter...
Article
Full-text available
In this study, the effect of the molecular weight of polyethyleneglycol (PEG) on the gas permeability and selectivity of a series of polyvinylchloride/polyethyleneglycol (PVC/PEG) blend membranes was investigated. The molecular weight of polyethylene glycol ranged from 400 to 4000. PVC/PEG blend membranes were prepared via thermal phase inversion o...
Article
The gas separation properties of ethylene vinyl acetate (EVA) membranes containing 18 and 28wt% of vinyl acetate (VA) were investigated in this study. The effects of membrane preparation conditions, such as thermal and thermal/wet phase inversion, and the type of solvent on the gas separation properties of EVA membranes were investigated. The perme...
Article
In this research, the effects of preparation conditions, including the coagulation bath temperature, polymer solution composition, preliminary drying time, and thickness of cast polymeric films, on the morphology of ethylene/vinyl acetate copolymer membranes were investigated with scanning electron microscopy and nitrogen gas permeability tests. Fl...
Article
Generalization performances of two different neural networks are compared with a conventional software for prediction of hollow fiber permeances and the corresponding separation factors. Two experimental data sets were used as the training data for separation of carbon dioxide from methane. Both Radial Basis Function (RBF) and Multi-layer Perceptro...
Article
Full-text available
The effects of water vapor on CO2/CH4 separation using commercially available poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and Cardo-type polyimide hollow fiber membranes were investigated. Pure methane and CO2/CH4 mixture permeation experiments were carried out in the absence and presence of water vapor (60% RH). Pure methane permeance decreased i...