Novel carbon nano-fibers (CNF)/polysulfone (PSf) mixed matrix membranes for gas separation

Mohsen Jahanshahi,Ahmad Rahimpour,Mohsen Jahanshahi,Ali Asghar Ghoreyshi 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.22 No.-

Mixedmatrixmembranes (MMM) included of carbon nanofibers (CNFs) fabricated and characterized forgas separation performance. For preparation of MMM, carbon nanofibers content was varied from 0.01 to1 wt% in polysulfone (PSf) casting solution. The fabricated CNFs/PSF MMMs characterized by scanningelectron microscopy (SEM), atomic force microscopy (AFM), ATR–FTIR spectra and pure gas permeationand sorption test. The gas transport properties ofMMMmeasured using single gas permeation set up (N2,O2, CO2, and CH4) at ambient temperature and different feed pressures. Additionally, sorption isothermsformixed matrixmembranesmade for CH4 and CO2. The sorption data were analyzed by the dual-modesorption model. Themorphological studies show that the incorporation of CNFs appreciably changed thesurface properties of membranes. The permeation test showed that the mixed matrix membraneexhibited high permeability. With increasing CNF concentration, CNFs/PSF membrane permeabilityraised from 2.134 to 12.04 Barrer for CO2. The results found that this unique membrane had increasedpermeability and enhanced selectivity. Also it has a great potential to be used practically in gasseparation technology.

Selective CO2 adsorption using N-rich porous carbon derived from KOH-activated polyaniline

Soodabeh Khalili,Mohsen Jahanshahi 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.4

The adsorption of pure gases of carbon dioxide, methane and nitrogen was examined on nitrogen-doped porous carbon (NDC) prepared from polyaniline (PANI) as precursor by chemical activation with KOH (T=650o, IR=2, t=1 h) to determine the potential for the separation of CO2 gas from flue gas or natural gas. Adsorption equilibrium of all gases was determined in a temperature range of 298-318 K and pressure up to 14 bar. Results demonstrated an excellent CO2 adsorption capacity of 3.09mmol·g-1 owing to high CO2 interaction affinity with NDC surface compared to CH4 (1.43mmol·g-1) and N2 (0.64mmol·g-1) under ambient condition (298 K and 1 bar). The ideal adsorbed solution theory (IAST) was used to determine the adsorption selectivity of NDC for CO2/CH4 and CO2/N2 mixtures at different compositions. The NDC had CO2/CH4 (4.42 and 4.08 for CO2/CH4=10/90 and 50/50, respectively) and CO2/ N2 (12.81 and 12.08 for CO2/N2=15/85 and 50/50, respectively) IAST selectivity at temperature of 298 K and pressure of 1bar. The moderate CO2 adsorption enthalpy indicates that N-doped activated carbon is a promising material in gas separation such as natural gas and flue gas processing.

Feasibility of hydrophobized PES membrane in hybrid MD/FO process using magnetic draw solution

Setareh Salehi,Mohsen Jahanshahi,Majid Peyravi 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.6

The feasibility of PES membrane with hydrophobic property, high glass transition temperature, excellentthermal and chemical stability, with good mechanical properties as porous polymeric support was studied in membranedistillation (MD) process. Several strategies were considered and investigated to decrease membrane wetting bykeeping up salt rejection and also to improve the permeate flux of PES membrane in the MD process. From this pointof view, hydrophobic PMHS polymer with different concentrations was used as a surface coating solution. The morphologyand structure of prepared membranes were evaluated by AFM and FESEM analyses. After coating modification,the salt rejection was increased up to 98% and the contact angle was changed from 65.11o to >100.2o. To increasethe water flux, the effect of feed temperature (55 oC and 75 oC) and draw solution utilization containing magneticnanoparticle (Fe3O4) was investigated. Using draw solution provided a driving force from feed solution to permeateside and increased average permeate flux from 2.9 kg/m2·h to 6.9 kg/m2·h in the 0.06 g/l of draw solute concentration. It improved permeate flux and salt rejection simultaneously.

Feasibility study of a novel copolyamide thin film composite membrane assisted by melamine in terms of acid and thermal stability

Hamzeh Hoseinpour,Mohsen Jahanshahi,Majid Peyravi,Ahmad Nozad 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.46 No.-

A new acid stable copolyamide [PEI-Mel]-PA membrane was developed via interfacial polymerizationassisted by melamine. The physico-chemical properties and separation ability were studied. It wascompared with an acid stable polysulfonamide membrane in terms of acid stability. Melamine improvedthe thermal and acid stability and made the surface of the membrane more positively charged. Thedecreases in MgSO4 rejections were 56% and 31% for [PEI-Mel]-PA membrane after H2SO4 and HNO3treatment, respectively. The stability of [PEI-Mel]-PA improved up to 16% and 48% in H2SO4 and HNO3,respectively in comparison with PEI-PA membrane. It recovered more than 97% of the acid.

Antibacterial dynamic membranes loaded by cephalexin/amine-functionalized SBA_15 for Pb(II) ions removal

Maryam Darzipour,Mohsen Jahanshahi,Majid Peyravi,Soodabeh Khalili 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.12

Novel antibacterial dynamic membranes loaded by cephalexin/amine functionalized SBA_15 were fabricated for heavy metal removal from aqueous solution. The mesoporous CPX/NH2-SBA_15 nanocomposite was formed as a uniform adsorptive and hydrophilic layer on the ultrafiltration polymeric membrane (PVDF). The modified adsorbent and membranes were characterized by SEM, XRD, N2 adsorption-desorption analysis, FT-IR, TGA, DSC and contact angle. A number of qualitative (well diffusion, disk diffusion) antibacterial assays were conducted against grampositive S. aureus and gram-negative E. coli. In addition, to evaluate its anti-biofouling performance, the model concentrated bacteria suspension in liquid medium was used as a feed solution. 100% bacteria mortality for certain concentration and suitable inhibition zones up to 3.5cm were attained. An increment in the flux recovery from 55% (for UF) to 87% (for self-forming dynamic membrane (DM)) and 91% (for pre-coated DM) indicated that the dynamic layer improved the anti-biofouling property of the support membrane. High Pb(II) removal efficiency (99.8%) was achieved for the modified membrane during dynamic filtration test. CPX/NH2/SBA-15 dynamic membrane showed higher Pb2+ rejection than SBA-15 dynamic membrane because of amine groups located on the adsorbent surface. In general, membranes provide good performance like better flux and rejection besides antibacterial and anti-biofouling behavior.

Self-cleaning behavior of nanocomposite membrane induced by photocatalytic WO3 nanoparticles for landfill leachate treatment

Majid Peyravi,Nader Shafaei,Mohsen Jahanshahi,Qasem Najafpour 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.10

Photocatalytic self-cleaning polysulfone (PSf) membranes were fabricated by adding different concentrations of WO3 nanoparticles (0-2 wt%) via phase inversion method for ultrafiltration of landfill leachate. To evaluate the feasibility of self-cleaning property by WO3 nanoparticles, all synthesized membranes were tested with and without UV. After UV irradiation, the value of the contact angle for a membrane with 2wt% WO3 decreased from 67.15o to 37.9o. Results showed that the addition of WO3 affected the pore size, porosity and hydrophilicity of the WO3/PSf membrane, so that the porosity of membrane with 2 wt% WO3 reached 84.86%. The flux of the nanocomposite membrane after irradiation by UV light rose in comparison with the same membrane without UV light, and the flux decline rates also decreased. The flux of the membrane with 2wt% WO3 was also better than the other membranes, which shows the self-cleaning property. The chemical oxygen demand (COD) removal of leachate for modified membranes was also improved by increasing the WO3 nanoparticles. The highest COD removal of the modified membrane with 2 wt% WO3 was 54.91%. This value increased to 77.45% after UV radiation.

A comparative study of CO2 and CH4 adsorption using activated carbon prepared from pine cone by phosphoric acid activation

Behnam Khoshandam,Soodabeh Khalili,Mohsen Jahanshahi 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.10

Adsorption of pure carbon dioxide and methane was examined on activated carbon prepared from pine cone by chemical activation with H3PO4 to determine the potential for the separation of CO2 from CH4. The prepared adsorbent was characterized by N2 adsorption-desorption, elemental analysis, FTIR, SEM and TEM. The equilibrium adsorption of CO2 and CH4 on AC was determined at 298, 308 and 318 K and pressure range of 1-16 bar. The experimental data of both gases were analyzed using Langmuir and Freundlich models. For CO2, the Langmuir isotherm presented a perfect fit, whereas the isotherm of CH4 was well described by Freundlich model. The selectivity of CO2 over CH4 by AC (CO2 : CH4=50 : 50, 298K, 5 bar), predicted by ideal adsorbed solution theory (IAST) model, was achieved at 1.68. These data demonstrated that pine cone-based AC prepared in this study can be successfully used in separation of CO2 from CH4.

Synthesis and characterization of PVA/PES thin film composite nanofiltration membrane modified with TiO2 nanoparticles for better performance and surface properties

Sarah Pourjafar,Ahmad Rahimpour,Mohsen Jahanshahi 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4

Novel polyethersulfone (PES)/poly (vinyl alcohol) (PVA)/titanium dioxide (TiO2) composite nanofiltration membranes were prepared by dip-coating of PES membrane in PVA and TiO2 nanoparticles aqueous solution. Glutaraldehyde (GA) was used as a cross-linker for the composite polymer membrane in order to enhance the chemical, thermal as well as mechanical stabilities. TiO2nanoparticles with different concentrations (0, 0.05, 0.1, 0.5 wt.%) were coated on the surface of PVA/PES composite membrane. The morphological study was investigated by atomic force microscopy (AFM), scanning surface microscopy (SEM) and along with X-ray diffraction (XRD). In addition, the membranes performances, in terms of permeate flux, ion rejection and swelling factor were also investigated. It was found that the increase in TiO2 solution concentration can highly affect the surface morphology and filtration performance of coated membranes. The contact angle measurement and XRD studies indicated that the TiO2 nanoparticles successfully were coated on the surface of PVA/PES composite membranes. However, rougher surface was obtained for membranes by TiO2 coating. The filtration performance data showed that the 0.1 wt.% TiO2-modified membrane presents higher performance in terms of flux and NaCl salt rejection. Finally, TiO2 modified membranes demonstrated the lower degree of swelling.

A new electrochemical biosensor for hydrogen peroxide using HRP/AgNPs/cysteamine/p-ABSA/GCE self-assembly modified electrode

Ali Shokuhi Rad,Mohsen Jahanshahi,Mehdi Ardjmand,Ali-Akbar Safekordi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.12

An electrochemical hydrogen peroxide biosensor was designed by immobilizing horseradish peroxidase (HRP) on Ag nanoparticles/cysteamine/p-aminobenzene sulfonic acid/glassy carbon (GC) electrode. Ag nanoparticles can act as tiny conduction centers on electrodes that adsorb redox enzymes, facilitating the transfer of electrons with no requiring any loss of biological activity. The forerunner film was first electropolymerized on the glassy carbon electrode with p-aminobenzene sulfonic acid (p-ABSA) by cyclic voltammetry. The cysteamine (CA) was bound on the surface of the film by electrostatic force, then Ag nanoparticles were immobilized on the cysteamine monolayer, and lastly HRP was adsorbed onto the surfaces of the Ag nanoparticles. A dramatic decrease in the overvoltage of H2O2was observed with improved sensitivity, which makes the modified electrodes of great promise for oxidase-based amperometric biosensors. The biosensor responded to H2O2 in the linear range from 1.2×106 mol/L to 9.8×103 mol/L with a detection limit of 1.1×108 mol/L. Moreover, the obtained biosensor exhibited good accuracy and high sensitivity.

PDADMAC/PAA semi-IPN hydrogel-coated PVDF membrane for robust anti-wetting in membrane distillation

Fatemeh Ardeshiri,Ahmad Akbari,Majid Peyravi,Mohsen Jahanshahi 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.74 No.-

In this study, composite membranes have been developed via deposition of poly(diallyldimethylammo-nium chloride)/poly acrylic acid (PDADMAC/PAA) semi-interpenetrating (semi-IPN) hydrogel on thepolyvinylidenefluoride (PVDF) support to provide an understanding the impacts of membrane surfacesand surfactants properties on wetting behavior in direct contact membrane distillation (DCMD)processes. The PDADMAC/PAA semi-IPN hydrogel membrane showed a wettability and underwateroleophobic properties with underwater oil contact angle over 125 , which favored reduction of oildeposition on the membrane surface. The long-term robustness of the PDADMAC/PAA-coated membranein 3 wt.% NaCl solution containing cationic, ionic and non-ionic surfactants was investigated via DCMDexperiments.