Synthesis and gas transport performance of MIL-101/Matrimid mixed matrix membranes

Masoomeh Naseri,Toraj Mohammadi,Seyed Foad Mousavi,Omid Bakhtiari 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.29 No.-

Mixed matrix membranes (MMMs) are composites of highly selective fillers within a polymeric matrix,resulting in higher selectivity and/or flux in gas separation applications. In this work, micron sized MIL-101 crystals with potential of gas separation by adsorption were synthesized and used as filler for thepreparation of MMMs for gas separation. Gas adsorption measurements were performed for CO2, CH4and N2 using MIL-101 crystals and the results showed significant adsorption of CO2 compared with thetwo other gases at different pressures. SEM images and XRD analysis were used to characterize the fillerparticles and the synthesized membranes. MIL-101/Matrimid MMMs were synthesized with up to30 wt.% loading of filler particles. SEM images showed good dispersion of the particles in the polymericmatrix and also good adhesion between the filler particles and the polymer. Permeability measurementswere performed for pure gases of CO2, CH4 and N2 and the results showed improved CO2/CH4 and CO2/N2ideal selectivities for the MMMs compared with those for the neat Matrimid membrane. For the MMMswith 10 wt.% loading, permeability of CO2 was found as 6.95 Barrer and ideal selectivities for CO2/CH4and CO2/N2 were as 55.77 and 52.92, respectively.

High performance antibiofouling hollow fiber polyethersulfone nanocomposite membranes incorporated with novel surface-modified silver nanoparticles suitable for membrane bioreactor application

Ali Behboudi,Toraj Mohammadi,Mathias Ulbricht 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-

Surface-modified silver nanoparticles with amine, thiol, carboxyl, and the thiol-polyvinylpyrroldidone(PVP) functional groups were synthesized as functional filler for nanocomposite membranes for membranebioreactor (MBR), with the aims to enhance antimicrobial effect of silver, while immobilizing silvernanoparticles inside the matrix of the membrane. Analyses by fourier transform infrared (FTIR), fieldemission scanning electron microscopy (FESEM), and dynamic light scattering (DLS) proved successfulsurface modification for each type of nanoparticles, with average particle sizes of 69, 20, 33, and34 nm for amine, carboxyl, thiol and thiol-PVP modified silver nanoparticles, respectively. Polyethersulfone (PES) based nanocomposite hollow fiber membranes showed different morphologyand performance in ultrafiltration and MBR experiments. The surface modifications were able to immobilizesilver nanoparticles inside the membrane by providing proper interactions between the nanoparticlesand polymer, reducing silver release compared to the unmodified nanoparticles. Modifiednanoparticles changed the phase inversion, resulting in different morphology and average pore size inthe range of 7.6–28.0 nm. The surface-modified nanoparticles with enhanced antimicrobial activityimproved antifouling properties of the nanocomposite membranes, leading to interesting MBR performanceimprovements, with 122 % increase of flux, 23 % increase of chemical oxygen demand (COD)removal and flux recovery by over 30 %.

Experimental investigation and modeling of industrial oily wastewater treatment using modified polyethersulfone ultrafiltration hollow fiber membranes

Abdolhamid Salahi,Toraj Mohammadi,Reza Mosayebi Behbahani,Mahmood Hemmati 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.6

Hollow fiber membranes were prepared from polyethersulfone/additives/NMP&DMSO system via phase inversion induced by precipitation in non-solvent coagulation bath. The interaction effects of polyethylene-glycol (PEG), propionic-acid (PA), Tween-20, PEG molecular weight and polyvinyl-pyrrolidone (PVP) on morphology and performance of synthesized membranes were investigated. Taguchi method (L16 orthogonal array) was used initially to plan a minimum number of experiments. 32 membranes were synthesized (with two replications) and their permeation flux and TOC rejection properties to oily wastewater treatment were studied. The obtained results indicated that addition of PA to spinning dope decreases flux while it increases TOC rejection of prepared membranes. Also, the result shows that addition of PVP, Tween-20 and PEG content in spinning dope enhances permeation flux while reducing TOC rejection. The obtained results indicated that the synthesized membranes was effective and suitable for treatment of the oily wastewater to achieve up to 92.6, 98.2, and 98.5% removal of TOC, TSS, and OGC, respectively with a flux of 247.19 L/(m2h). Moreover, Hermia’s models were used for permeation flux decline prediction. Experimental data and models predictions were compared. The results showed that there is reasonable agreement between experimental data and the cake layer model followed by the intermediate blocking model.

Preparation of organic-filled compatible nanocomposite membranes for enhanced CO2 permselectivity

Zahra Rezaee,Toraj Mohammadi,Omid Bakhtiari 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-

Ideally structured nanocomposite membranes may possess the maximum desired separation propertiesof both filler particles and the host polymer matrix. To approach this goal in this study, some nanocompositedense membranes were prepared using Pebax 1657 and polyaniline nanofiber (PANI) with closedstructural properties in their different concentrations by applying various ethanol/water solvent mixturesand the solution method casting and solvent evaporation phase inversion. The structural characteristicsof the membranes were evaluated using SEM, FTIR (ATR), and XRD analysis and then their CO2 and CH4permeabilities were measured. The structural analysis revealed that the prepared nanocomposite membraneshave defect-free structures and the amorphous PANI nanofibers were dispersed uniformly withinthe nanocomposite membranes leading to their lower crystallinities. As the nanofiber loading increasedin the continuous phase, both CO2 permeability and selectivity of the nanocomposite membranes wereincreased simultaneously and passed over the 1991 Robeson upper bound limit and approached thatof 2008. CO2 permeability and ideal CO2/CH4 selectivity of the nanocomposite membrane loaded by 10wt. % of the PANI nanofibers were increased to 121.2 Barrer and 33, respectively, revealing 64 and 40% increments.

Water desalination via novel positively charged hybrid nanofiltration membranes filled with hyperbranched polyethyleneimine modified MWCNT

Mohammad Peydayesh,Toraj Mohammadi,Omid Bakhtiari 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-

Novel positively charged hybrid nanofiltration membranes were fabricated via incorporation of hyperbranched polyethyleneimine modified multiwall carbon nanotubes into polyethersulfone matrix. The main aim of this research is induction of positive charge to negatively charged polymeric membrane by means of self-assembly of positively charged nanoparticles via phase inversion technology. The prepared membranes were evaluated in terms of morphology, surface properties, thermal and mechanical stabilities, nanofiltration performance and antifouling property. The best hybrid membrane with loading of 0.6% of nanoparticles, showed high thermal and mechanical stabilities with mean pore size, molecular weight cut off (MWCO) and isoelectric point of 0.81 nm, 600 Da and 10, respectively. Pure water flux (PWF) of the hybrid membrane compared to the neat polyethersulfone membrane was enhanced 109% and reached to 75.7 L/m2 h. Effects of pressure, temperature, feed concentration and feed pH on separation performance of the membranes were also investigated. The hybrid membrane represented superior performance for heavy metals removal in rejection order of Zn (99.06%) > Mg (97.36%) > Cd (96.72%) > Cu (95.84%) > Ca (95.25%) > Ni (94.63%) > Pb (93.39%), indicating domination of Donnan exclusion mechanism. In addition, the hybrid membrane with higher hydrophilicity and lower roughness showed improved antifouling property and life span.

Synthesis and characterization of ceramic/carbon nanotubes composite adsorptive membrane for copper ion removal from water

Maryam Ahmadzadeh Tofighy,Toraj Mohammadi 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.2

We prepared a novel adsorptive membrane by implanting carbon nanotubes (CNTs) in pore channels ofceramic (α-alumina) support via chemical vapor deposition (CVD) method using cyclohexanol and ferrocene as carbonprecursor and catalyst, respectively. Optimization of CNTs growth conditions resulted in uniform distribution ofthe CNTs in the pore channels of the support. The optimized CNTs-ceramic membrane was oxidized with concentratednitric acid, and chitosan was employed for filling intertube-CNT gaps. The modified CNTs-ceramic membranewas used for copper ion removal from water, and the effects of the modification steps (oxidation and filling intertube-CNT gaps with chitosan) and pH on permeation flux and rejection of the prepared adsorptive membrane were investigated. Moreover, static adsorption was also investigated and Langmuir and Freundlich isotherms and two kineticsmodels were used to describe adsorption behavior of copper ions by the prepared adsorptive membrane.

Mathematical modeling of mass transfer in multicomponent gas mixture across the synthesized composite polymeric membrane

Abtin Ebadi Amooghin,Toraj Mohammadi,Pardis Moradi Shehni,Ali Ghadimi,Mohtada Sadrzadeh 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3

This study presents a new mathematical model to investigate the ternary gas mixture permeation across a synthesized composite PDMS/PA membrane. A novel algorithm is introduced for direct determination of diffusion coefficients. It pertains to study gas permeation through concentration dependent systems and comparing with traditional time lag method confirms the precision of this approach. Feature is that this method does not require physical properties of the membrane. Accordingly, it can be used as a general comprehensive model. In addition, molecular pair and molecular trio interactions were taken into account and in order to investigate the deviation of gas mixture from ideality, fugacities were calculated. The results showed that permeabilites of H2 and CH4 increase with increasing feed temperature and fugacity, while that of C3H8 decreases. Moreover, increasing C3H8 concentration improved permeation properties of all components. The results demonstrated that considering the concentration dependent system (CDS) leads to the small deviation of about less than 10%, while the deviation of 50–100% by the concentration independent system (CIS) was acquired. Additionally the results indicated that permeability of the lighter gases is specially affected by diffusivity, while solubility is dominant on permeability of the heavier gases.

Effect of halloysite nanotubes incorporation on morphology and CO2/CH4 separation performance of Pebax-based membranes

Seyed Mohammad Ali Ahmadi,Toraj Mohammadi,Navid Azizi 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.1

Mixed-matrix gas separation membranes were prepared by embedding various content of halloysite nanotubes (HNTs) (0, 0.5, 1, 1.5, and 2 wt%) within poly (ether-block-amide) matrix. XRD, FT-IR, TGA, and SEM analyses were conducted to study crystal structure, chemical bonds changes, thermal resistance, and cross-sectional morphology of the resultant membranes, respectively. Permeability values of pure CH4 and CO2 gases through the synthesized neat and mixed-matrix membranes (MMMs) were experimentally determined at constant temperature (25 oC) and several pressures (4, 6, 8, and 10 bar). The obtained results exhibited improved CO2 permeability of the MMMs comparing with the pristine Pebax membrane. As an example, at a pressure of 4 bar, raising the incorporated HNTs loading from 0 to 2wt% enhanced the permeability of CO2 from 76.50 to 101.23 Barrer.

Synergistic extraction and separation of Dysprosium and Europium by supported liquid membrane

Parisa Zaheri,Hossein Abolghasemi,Toraj Mohammadi,Mohammad Ghannadi-Maragheh 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.8

Synergistic extraction and separation of Dysprosium (Dy) and Europium (Eu) via supported liquid membrane (SLM) were investigated using mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and Bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex272). The results showed that separation of Dy and Eu was highly dependent on the pH of feed solution. Dy can be extracted more than Eu, because the equilibrium constant for Dy using the mixture of D2EHPA and Cyanex272 was greater than that for Eu. Various parameters were optimized to achieve maximum separation factor, namely feed phase pH, carrier concentration and stripping phase concentration. The membrane was stable at six cycles of operation.

Simulation of momentum, heat and mass transfer in direct contact membrane distillation: A computational fluid dynamics approach

Hossein Hayer,Omid Bakhtiari,Toraj Mohammadi 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Membrane distillation is one of the newest methods for water purification. In this study, the behavior ofdirect contact membrane distillation (DCMD) process under various operating conditions wasmathematically modeled using computational fluid dynamics (CFD) method. The effects of differentparameters on transmembrane flux and temperature polarization coefficient (TPC) were measured byglobal sensitivity analysis technique. The sensitivity analysis results indicated that the most affectingdesign parameters in DCMD are membrane thickness and feed temperature.