Types Of Mixed Matrix Membranes Research Articles

Pine cone derived polyethersulfone/biochar-Fe3O4 mixed matrix membranes for removal of arsenic from acid mine drainage

In this study novel type of mixed matrix membranes (MMMs) were prepared through phase inversion. This fabricated MMMs were impregnated with biochar (BC) and biochar-Fe3O4 (FBC) composites for selective removal of As(V) ions from acid mine drainage through the adsorptive-filtration processes. Scanning electron microscopy (SEM) images revealed that the BC and FBC adsorbents had heterogeneous surface morphologies with varying particle diameters. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the existence of polar functional groups, which aided the improvements in the adsorptive removal of As(V) ions. BET surface area increased from 8.32 m2/g of pristine BC adsorbent to 19.90 m2/g for the FBC adsorbents. Pure water flux increased from 239.9 L/m2.h (M0) to 359.4 L/m2.h (M6), and the water contact angle decreased from 70.7° (M0) to 51.4° (M6). The maximum adsorption capacity achieved was 34.92 mg/g and 49.54 mg/g for BC and FBC MMMs, respectively, at pH 10. The adsorption isotherms and kinetics were analyzed using the Freundlich model and Pseudo-first-order model, respectively, which provided the best-fit to the experimental data. Consequently, the adsorption isotherm data indicated that the removal of As(V) ions was influenced by electrostatic interaction, hydrogen bonding, diffusion (pore filling), and inner-sphere complexation mechanisms. Furthermore, the leaching rate of FBC from membrane labelled M6 was investigated at various pH levels, showing rates of 2.01 µg/m2.h, 0.09 µg/m2.h, and 0.08 µg/m2.h at pH 2, pH 7 and pH 10, respectively. The decrease in leaching rate observed under neutral (pH 7) and basic (pH 10) conditions is ascribed to the improved stability of Fe3O4 NPs within the membranes. The membrane containing 1.5 wt% of FBC demonstrated enhanced effectiveness in removing toxic metals not only for As (99.9 %) but also Cr (99.8 %). These findings indicate that the membrane has great potential towards the treatment of acid mine drainage.

Utilization and performance evaluation of mixed matrix membranes for the treatment of produced water: A review

Produced water (PW) has been generated in a huge amount representing the largest volume waste stream. Membrane technology has found a leading ability in treating PW due to its significant advantages, such as lower cost, easy installation, and being environmentally friendly. Mixed matrix membranes (MMMs) have received significant research interest due to their flexibility, multifunctionality enhances the membrane performance with increasing selectivity, permeability, robustness, mechanical strength, and resistance to fouling. This mini-review paper identifies the utilization of different membranes for treating PW. It also gives a holistic review of different types of MMMs with specific fillers for the application of PW treatment. Lastly, some methods to enhance the performance of mixed matrix membranes have been highlighted. The issues and challenges in membranes are also discussed.

Mixed-matrix membranes containing zero-dimension porphyrin-based complex for propylene/propane separation

The membrane-based technology for propylene/propane (C3H6/C3H8) separation is very promising due to its low-energy separation process with high effectiveness. Herein, we propose a new type of mixed-matrix membranes (MMMs) containing zero-dimension non-porous porphyrin-based complex (M-TMCPP, M = Zn2+, Cd2+, Ni2+) with coordinatively unsaturated metal sites. Density functional theory calculation results show that M-TMCPP can form π complexation with C3H6 and facilitate C3H6 molecule through membranes. Different from porous nanofillers, M-TMCPP exhibits zero-dimension non-porous molecular structure and can be dissolved in solvent at molecular lever under low concentration. Benefiting from the favorable interaction between C3H6 with metal sites and the uniform distribution of M-TMCPP particles and/or even independent M-TMCPP molecules in polymer, the porphyrin-based complexes are used as nanofillers in fluorinated polyimide (6FDA-DAM). The prepared MMMs exhibit an extraordinary C3H6/C3H8 ideal selectivity of up to 45.6 with a high C3H6 permeability of 70.3 Barrer, far surpassing the previously reported 6FDA-based polyimide MMMs and polymeric membranes. Membrane performances of three different M-TMCPP MMM were studied and the gas transportation mechanism was evaluated. This work provides a new conceptual approach of using non-porous zero-dimensional complexes with coordinatively unsaturated sites as fillers in mixed matrix membranes, which not only can accomplish olefin/alkane separation with ultrahigh performance, but also indicates its high potential for feasible usage.

Mixed matrix membranes comprising dual-facilitated bio-inspired filler for enhancing CO2 separation

In this work, a novel dual-facilitated bio-inspired zeolitic imidazolate framework (Bio-ZIF) was proposed to simulate the structure and function of carbonic anhydrase (CA), because it can overcome the low stability and high price of the CA. A novel type of mixed matrix membrane (MMM)-composed of Bio-ZIF and Pebax® MH 1657 (Pebax) was fabricated and used to enhance CO2 separation performance. The bio-inspired active sites of Bio-ZIF can catalyze the reversible hydration of CO2 in the form of bicarbonate to facilitate the quick transport of CO2 across the MMMs, increasing CO2 permeability. Furthermore, the amino groups of Bio-ZIF reacted with CO2 to produce zwitterion as an intermediate during the reversible reaction, facilitating CO2 permeation in the MMMs. It can be concluded that Bio-ZIF performed the dual-facilitated functions in the MMMs by reversible hydration and reversible reaction with CO2 molecules. Thus, the as-prepared MMMs exhibited an excellent CO2 separation performance. Particularly, Pebax/Bio-ZIF-12 MMM presented an optimal CO2 permselectivity with CO2 permeability of 542 ± 6.0 Barrer and CO2/CH4 separation factor of 40 ± 0.4, surpassing the 2008 upper bound. This work provided an ingenious strategy to design bio-inspired fillers to achieve dual-facilitated functions in MMMs for enhancing CO2 separation.

Hydrogen-bonded polyamide 6/Zr-MOF mixed matrix membranes for efficient natural gas dehydration

New types of mixed matrix membranes (MMMs) were fabricated by incorporating Zr-MOF (UiO-66-NH2 and UiO-66-NH3+Cl-) filler into polyamide 6 (PA 6) polymer, enabling efficient natural gas dehydration. All membranes were characterized and applied for H2O/CH4 mixtures separation at 1 bar pressure difference at 30 °C. It was found that the Zr-MOF nanoparticles in a size range of 0.4–0.5 μm were successfully incorporated into the high permeability polymer PA 6 to obtain MMMs with 10–30 wt% particle loadings. MMMs loaded with 25 wt% of UiO-66-NH3+Cl- and 20 wt% of UiO-66-NH2 demonstrated ultrahigh H2O/CH4 selectivity of 747.7 and 687.4, respectively, and enhanced H2O permeability as well as H2O/CH4 selectivity compared with the pure PA 6 polymer. The excellent membrane performance attributed to direct and extensive hydrogen bonds between the polymer and MOFs. This type of MMMs could be an alternative for further research in H2O/CH4 separation at industrial scale.

Enhancement of CO2 permeation properties of polymeric membrane by incorporating metal organic framework

This research work focuses on the fabrication of mixed matrix membranes (MMMs) for the enhancement of CO2 removal from CH4. Zeolitic imidazolate framework (ZIF-8) with a framework of 0.34 nm pore size which favours CO2 adsorption is used as filler in this work. Different loadings of ZIF-8 filler were incorporated into polysulfone (PSf) polymer matrix. From the EDX mapping, the morphology of the ZIF-8/PSf MMMs has shown compatibility between the polymer and filler phases. The MMMs demonstrated an increment of 8°C in glass transition temperature, Tg compared to the pure PSf. Based on the permeation results, MMM loaded with 1 wt% of ZIF-8 showed the highest performance with CO2 and CH4 permeability of 33.12 Barrer and 0.85 Barrer respectively, and CO2/CH4 ideal selectivity of 38.8. The development of this new type of MMM has great potential to be utilized in CO2/CH4 separation process.

Ferrous sulfide and carboxyl-functionalized ferroferric oxide incorporated PVDF-based nanocomposite membranes for simultaneous removal of highly toxic heavy-metal ions from industrial ground water

The deterioration of the aquatic environment by the heavy metal ions contamination causes serious threat to environment and human beings. However, the treatment of complex industrial wastewater by simultaneous removal of multiple heavy metal ions via a one-step method is still extremely challenging. To this end, we synthesize ferrous sulfide (FeS) and carboxyl-functionalized ferroferric oxide (CFFO) nanoparticles, which were introduced into polyvinylidene fluoride (PVDF) matrix (individually/mixed together in an optimum ratio) through phase inversion technique. Three types of mixed matrix membranes (MMMs) were developed, viz. FeS/PVDF, CFFO/PVDF and FeS/CFFO/PVDF. The prepared membranes were characterized by SEM, TEM, AFM, FTIR, XRD, BET, and XPS techniques. The properties of the membranes were also examined for pure water flux, hydrophilicity, water uptake capacity, mechanical and thermal property, salt separation and simultaneous separation of toxic heavy metal ions such as lead, (Pb), cadmium (Cd), and chromium (Cr) from industrial ground water. The resultant membranes exhibited relatively high water flux (340–1266 L/m2h) than the unmodified PVDF membrane, due to changes in the porosity and hydrophilicity of the membranes. FeS/CFFO/PVDF membrane showed that it could effectively treat Pb, Cd, Cr and As contaminated industrial ground water, simultaneously with a high removal efficiency of about 88% for Cr(VI), 99% for Cd2+, 99% for Pb2+ and 95% for As in a single filtration process. In addition, the developed membranes conspicuously reduce their concentrations below the maximum contaminant level of WHO and BIS (India). The probable mechanism of separation of heavy metal ions through MMMs could be understood through FTIR and XPS techniques. The results of this study inferred that FeS/CFFO/PVDF membrane is a potential candidate for the simultaneous separation of Pb, Cd, Cr, and As.

Fabrication of Amino-Functionalized CAU-1/Cellulose Acetate Mixed Matrix Membranes for CO<sub>2</sub>/N<sub>2</sub> Separation

In this work, a new type of mixed matrix membranes comprising of amino-functionalized CAU-1 as filler and cellulose acetate as polymer phase were fabricated for CO2 separation from N2. The crystallinity and morphology of the resultant fillers were verified by using X-ray diffraction (XRD) and scanning electron microscope (SEM). The energy-dispersive X-ray (EDX) results showed that, sedimentation and agglomeration of fillers were found at loading of more than 5 wt%. Subsequently, the gases permeation results revealed that, an increase in CO2 permeability and CO2/N2 selectivity of 149% and 81%, respectively, were achieved for the membrane loaded with 5 wt% of CAU-1-NH2, as compared to pure cellulose acetate membrane.

Estimation of interphase properties of various mixed matrix membranes

ABSTRACTA generalized course of action was proposed for determining the separation properties of the interphase between filler and polymer phases in various mixed matrix membranes (MMMs). Accordingly, the permeability and thickness of the interphase were estimated by using the modified form of effective medium theory (EMT) and CO2, N2 and CH4 permeability data at two different filler loadings obtained from the literature. In spite of the sensitivity of the estimations to experimental inconsistencies in the data used, significant information could generally be obtained about the interphase permeability and thickness. It was observed that the interphase in different types of MMMs could have dissimilar separation properties even when the polymer used was the same. The CO2/CH4 ideal selectivities of the interphase between graphene oxide and polyether block amide (Pebax) polymer and the interphase between zeolite Y and a polyimide polymer, Matrimid, were determined to be higher than the selectivities of the pure polymers. Tailoring the interphase by having good knowledge of its properties, is expected to provide significant means for further improvement of the performances of mixed matrix membranes.

Prediction of CO2 Permeability in NH2-MIL-53(Al)/Cellulose Acetate Mixed matrix Membranes using Theoretical Models

Estimation of CO2 permeability of mixed matrix membranes (MMMs) using models has importance for the design of membrane separation system. In the current article, the previously reported models were used for the calculations of CO2 permeability through new type of MMMs, NH2-MIL-53(Al)/CA. It was found that modified Maxwell model demonstrated the absolute average error (AARE %) of 1.66%, which is lower than the AARE% obtained from the other theoretical models. Besides, the results also showed that AARE% of models for the prediction of CO2 permeability was in the order of modified Maxwell model < Lewis-Nielsen model < Fleski model < Bruggeman model < Pal model< modified Fleski model < Maxwell model. Therefore, it can be concluded that modified Maxwell model is more accurate compared to other theoretical models for the prediction of CO2 permeability through NH2-MIL-53(Al)/CA MMMs.

Development of a novel graphene oxide-blended polysulfone mixed matrix membrane with improved hydrophilicity and evaluation of nitrate removal from aqueous solutions

In this study, four types of mixed matrix membranes were fabricated using polysulfone (as the base polymer) and different contents of graphene oxide (GO) nanosheets (as modifier) through wet phase inversion method. Based on the amounts of GO (0, 0.5, 1, and 2 wt%), the synthesized membranes named as M1, M2, M3, and M4, respectively. The membranes characteristics were evaluated using FE-SEM, FT-IR, and water contact angle measurements. In addition, the performance of the prepared membranes was investigated in terms of basic parameters: filtrate water flux, nitrate removal efficiency, and antifouling properties. Results showed significant improvements of the characteristics of modified membranes with GO. Accordingly, the permeability and hydrophilicity were enhanced and water flux was considerably improved. At operating pressure of 4 bar and nitrate concentration of 110 mg/L, the removal efficiency for unmodified membrane (M1) was 15.5% and for modified M2, M3, and M4 membranes were 22.78%, 39.12%, and 41.37%, respectively. In addition, the results of flux recovery ratio (FRR) showed that the anti-fouling properties of the GO modified membranes were improved due to the increase in membrane surface hydrophilicity.

Recent progress of fillers in mixed matrix membranes for CO 2 separation: A review

Abstract Among various CO2-mitigation technologies, membrane-based technology has offered a more energy efficient and eco-friendly process for CO2 separation from large emission sources, in order to reduce CO2 emission level into atmosphere. In general, polymeric and inorganic membranes have been used in gas separation processes, but each has its own pros and cons. Currently, membrane research has addressed the trade-off limitations of membranes in different ways through fabrication of new type of mixed matrix membranes (MMMs) by incorporation of inorganic particles as fillers into polymer matrices. The performance of MMMs depends on textural properties of fillers, molecular sieving effect and membrane–penetrant interactions. The main challenges in the fabrication of MMMs is selection of fillers, which controls the gas separation characteristics of membranes. In this review, the influences of fillers like zeolite, carbon, and metal organic framework in MMMs fabrication and their CO2 permeability and CO2/CH4 and CO2/N2 selectivity were compiled from recent reports. Further, a new protocol is introduced for screening of fillers, which will helps to development of new fillers as well as for fabrication of new MMMs with high CO2 separation capacity.

Novel mixed matrix membranes incorporated with dual-nanofillers for enhanced oil-water separation

Abstract In this work, a new type of mixed matrix membranes (MMMs) composed of dual-nanofillers at different ratios of hydrous manganese oxide (HMO) and titanium dioxide (TiO2) was fabricated with the objective of improving properties of polyethersulfone (PSF)-based membrane for oil-water separation process. The morphology and surface chemistry of the resultant MMMs were characterized by several analytical instruments, i.e., SEM-EDX, contact angle goniometer and FTIR spectrometer prior to separation performance evaluation using oily solution composed of 500 or 2000 ppm. The results showed that the membrane surface hydrophilicity was greatly improved upon addition of hydrophilic nanofillers and HMO in particular showed greater extent of hydrophilicity enhancement owing to the fact that it is associated with higher amount of OH functional groups compared to TiO2. The improved surface hydrophilicity coupled with formation of long finger-like voids in the membrane structure are the main factors leading to greater water flux of MMMs in comparison to control PES membrane. MMM2 (membrane made of HMO:TiO2 ratio of 0.75:0.25) and MMM4 (HMO:TiO2 ratio of 0.25:0.75) in particular were the best two performing nanofillers-incorporated membranes owing to their good balance between water flux and oil removal rate. They achieved 31.73% and 26.41% higher water flux than that of the control membrane without sacrificing oil removal rate. Most importantly, these nanofillers-incorporated membranes showed significantly lower degree of flux decline as a result of improved surface resistance against oil fouling and are of potential for long-term operation with extended lifespan.

Graphitic carbon nitrides modified hollow fiber solid phase microextraction for extraction and determination of uric acid in urine and serum coupled with gas chromatography-mass spectrometry.

An elevated uric acid (UA) in urine or serum can affect renal function and blood pressure, which is an indicator of gout, cardiovascular and renal diseases, hypertension, etc. In this work, a new type of mixed matrix membrane (MMM), based on graphitic carbon nitrides (g-CNs) and hollow fiber (HF), was prepared and combined with solid phase microextraction (SPME) mode to determine UA in urine and serum followed by gas chromatography-mass spectrometry (GC/MS). The porous g-CNs were dispersed in ammonia, and then the exfoliated g-CNs nanosheets were held in the pores of HF by capillary forces and sonification. The prepared g-CNs modified HF (g-CNs-HF) was immersed in biofluid directly to extract UA with SPME mode and the solvent-free mode is convenient for further derivatization and analysis. To achieve the highest extraction efficiency (EF), main extraction and derivatization parameters, such as g-CNs-HF immobilizing time, sonification power and time of extraction, derivatization and desorption time, were optimized. Under the optimum extraction conditions, a favorable linearity of UA was obtained in the range 0.1-200μgmL(-1) with correlation coefficients higher than 0.9990, and the average recoveries at three spiked levels of UA in urine and serum ranged from 80.7% to 121.6%, from 84.7% to 101.1%, respectively. The obtained results demonstrated the developed g-CNs-HF-SPME is a simple, rapid, cost-effective, solvent-free method for the analysis of UA in biofluid.

Synthesis and characterization of a novel type of mixed matrix membrane: surface sieving membrane

A novel surface sieving membrane was prepared by attaching zeolite crystals on the polymer membrane surface. The top zeolite layer serves as a pre-screen layer which only allows the permeation of small molecules based on a molecular sieving mechanism. The separation factor of the new membrane was substantially increased by 300% for the pervaporation separation of a methanol–dimethyl carbonate mixture.

Theoretical and experimental studies on the gas transport properties of mixed matrix membranes based on polyvinylidene fluoride

The effects of the impregnation of three types of inorganic fillers into polyvinylidene fluoride (PVDF) polymer membranes on the gas permeability and selectivity of these membranes were studied theoretically and experimentally. Permeabilities of He, CO2, O2, and N2 through three types of mixed matrix membranes (MMMs) based on PVDF, that is, PVDF/SiO2, PVDF/MCM‐41, and PVDF/4A MMMs, were experimentally measured and theoretically predicted using Maxwell, Higuchi, Bruggeman, and Bottcher‐Landauer models. Theoretical permeabilities of the PVDF/SiO2 MMMs using the above four models predicted the results in the following order: Maxwell model&gt;Bruggeman model&gt;Bottcher model&gt;Higuchi model. However, this sequence was reversed for PVDF/MCM‐41 MMMs. The nonporous SiO2, mesoporous MCM‐41 and zeolite 4A inorganic fillers had effects on the permeabilities of the challenge gases for the PVDF/SiO2, PVDF/MCM‐41, and PVDF/4A MMMs but had no effects on the selectivities of the MMMs. The experimental permeabilities of the MMMs showed that there were no significant differences among the three types of MMMs despite that the inorganic fillers, that is, SiO2, MCM‐41, and zeolite 4A, had distinct dissimilar properties such as pore structures and particle sizes. Density measurements indicated that some voids were present in the polymer/particle interfaces. Based on the density measurement results, the void volume fractions of the resulting MMMs were calculated. An equation is derived to determine the void thickness of the MMM in terms of its physical properties and hence this proposed equation can substitute the difficult task of measuring such void thickness through any microscopy techniques. The Maxwell, Higuchi, Bruggeman, and Bottcher‐Landauer models could not predict the actual gas permeabilities of the PVDF MMMs. By taking the effects of crystallinity and immobilization factor on gas permeability into consideration, the extended modified Maxwell model showed good agreement with the experimental gas permeabilities of the resulting MMMs, indicating that the model did capture the essence of the gas transport behaviors through the MMMs. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4715–4726, 2013

Increasing the Performance of PES-CNTs Mixed Matrix Membrane using Carbon Nanotubes (CNTs) Functionalization

A new type of mixed matrix membrane consisting of functionalized carbon nanotubes (CNTs) and polyethersulfone (PES) is prepared for biogas purification. PES mixed matrix membrane with and without modification of carbon nanotubes were prepared by a dry/wet phase inversion technique using a pneumatically flat sheet membrane casting machine system. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using Dynasylan Ameo (DA) silane agent to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties, the productivity and purity of biogas. For PES-modified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO2/CH4 is 36.78

The Uses of Carbon Nanotubes Mixed Matrix Membranes (MMM) for Biogas Purification

A new type of mixed matrix membrane consisting of polyethersulfone (PES) and carbon nanotubes (CNTs) is prepared for biogas purification application. PES mixed matrix membrane with and without modification of carbon nanotubes were prepared by a dry/wet phase inversion technique using a pneumatically membrane casting machine system. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using acid treatment to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties and the permeability of all gases. For PES-modified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO2/CH4 is 23.54.

CO2 Removal from Biogas Using Carbon Nanotubes Mixed Matrix Membranes

A new type of mixed matrix membrane consisting of polyethersulfone (PES) and carbon nanotubes (CNTs) is prepared for biogas purification application. PES mixed matrix membrane with and without modification of carbon nanotubes were prepared by a dry/wet phase inversion technique using a pneumatically membrane casting machine system. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using acid treatment to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties and the permeability of all gases. For PES-modified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO 2/ CH 4 is 23.54

The Effect of Functionalization Carbon Nanotubes (CNTs) on the Performance of PES-CNTs Mixed Matrix Membrane

A new type of mixed matrix membrane consisting of functionalized carbon nanotubes (CNTs) and polyethersulfone (PES) is prepared for biogas purification. PES mixed matrix membrane with and without modification of carbon nanotubes were prepared by a dry/wet phase inversion technique using a pneumatically flat sheet membrane casting machine system. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using Dynasylan Ameo (DA) silane agent to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties, the productivity and purity of biogas. For PES-modified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO 2 /CH 4 is 36.78