96 results found
Jiang S, Ladewig B, 2020, Green synthesis of polymeric membranes: recent advances and future prospects, Current Opinion in Green and Sustainable Chemistry, Vol: 21, Pages: 1-8, ISSN: 2452-2236
Polymeric membranes are widely used in gas separations, liquid separations, and other processes such as fuel cells. However, methods and processes for manufacturing these membranes are usually harmful to the environment and/or human health. Although many new materials and synthesis methods are reported every year, green synthesis only makes up a small proportion. Therefore, more efforts are necessary to raise researchers’ awareness to green synthesis of membranes. One popular strategy to greenly synthesize membranes is to avoid toxic organic solvents or use water to replace organic solvents completely. However, many reported green methods could only realize green synthesis partly. The ultimate goal is to synthesize membranes in a completely eco-friendly way, where raw materials, membrane preparation, post-treatment, and other involved procedures are all “green”.
Prasetya N, Himma N, Sutrisna PD, et al., 2019, A review on emerging organic-containing microporous material membranes for carbon capture and separation, Chemical Engineering Journal, ISSN: 1385-8947
Membrane technology has gained great attention as one of the promising strategies for carbon capture and separation. Intended for such application, membrane fabrication from various materials has been attempted. While gas separation membranes based on dense polymeric materials have been long developed, there is a growing interest to use porous materials as the membrane material. This review then focuses on emerging porous materials to be used for the fabrication of membranes that are designed for CO2 separation. Criteria for selecting microporous material are first discussed, including physical and chemical properties, and parameters in membrane fabrication. Membranes based on emerging porous materials, such as metal-organic frameworks, porous organic frameworks, and microporous polymers, are then reviewed. Finally, special attention is given to recent advances, challenges, and perspectives in the development of such membranes for carbon capture and separation.
Xie M, Prasetya N, Ladewig B, 2019, Systematic screening of DMOF-1 with NH2, NO2, Br and azobenzene functionalities for elucidation of carbon dioxide and nitrogen separation properties, Inorganic Chemistry Communications, Vol: 108, Pages: 1-5, ISSN: 1387-7003
In this study, dabco MOF-1 (DMOF-1) with four different functional groups (NH2, NO2, Br and azobenzene) has been successfully synthesized through systematic control of the synthesis conditions. The functionalised DMOF-1 is characterized using various analytical techniques including PXRD, TGA and N2 sorption. The effect of the various functional groups on the performance of the MOFs for post-combustion CO2 capture is evaluated. DMOF-1s with polar functional groups are found to have better affinity with CO2 compared with the parent framework as indicated by higher CO2 heat of adsorption. However, imparting steric hindrance to the framework as in Azo-DMOF-1 enhances CO2/N2 selectivity, potentially as a result of lower N2 affinity for the framework.
Abbasi Z, Cseri L, Zhang X, et al., 2019, Metal-organic frameworks (MOFs) and MOF-derived porous carbon materials for sustainable adsorptive wastewater treatment, Sustainable Nanoscale Engineering: From Materials Design to Chemical Processing, Pages: 163-194, ISBN: 9780128146811
Jiang S, Ladewig B, 2019, High performance cation exchange membranes synthesized via in-situ emulsion polymerization without organic solvents and corrosive acids, Journal of Materials Chemistry A, Vol: 7, Pages: 17400-17411, ISSN: 2050-7496
The synthesis of cation exchange membranes (CEMs) usually involves using organic solvents and/or a sulfonation process. In this study, green and scalable synthesis of high performance CEMs is achieved without organic solvents and sulfonation. The synthesis is carried out via in situ polymerization of lithium styrene sulfonate in a porous support. Different preparation procedures are developed and optimized. Functional sulfonate groups are successfully loaded onto and into the membrane support, as verified by FTIR. Besides, water plays an important role in membrane synthesis. By reducing the amount of water used, the ratio of functional polymers to the membrane support in the synthesized CEMs is increased. Therefore, the synthesized CEMs show increased ion exchange capacity (IEC). This is significant because it means that high IEC can be achieved without introducing cation exchange resins into the membranes. Finally, the synthesized membranes demonstrate high desalination performance. This new methodology may shed new light on preparing CEMs in an efficient and eco-friendly way.
Slater B, Wong S-O, Duckworth A, et al., 2019, Upcycling a plastic cup: one-pot synthesis of lactate containing metal organic frameworks from polylactic acid, Chemical Communications, Vol: 55, Pages: 7319-7322, ISSN: 1359-7345
Waste PLA can be upcycled to metal organic frameworks of potential high value in a one-pot synthesis scheme, where PLA depolymerisation occurs in situ. Three homochiral lactate based frameworks were successfully synthesised and characterised from PLA as a feed source, including ZnBLD. The chiral separation ability of ZnBLD was maintained.
Prasetya N, Ladewig BP, 2019, An insight on the effect of azobenzene functionalities studied in UiO-66 framework for low energy CO2 capture and CO2/N2 membrane separation, Journal of Materials Chemistry A, Vol: 7, Pages: 15164-15172, ISSN: 2050-7496
In this paper, a simple approach to study the fundamental aspect of light-responsive metal organic framework (MOF) in UiO-66 topology through mixed-ligand approach is reported. Apart from change in the structural property, the loading of azobenzene linker inside the framework also affects the CO2 light-responsive property and CO2/N2 selectivity which could help to design the future low-energy CO2 adsorbent. Further study to incorporate the MOFs into mixed matrix membranes using PIM-1 as the polymer matrix also indicates the benefits of having higher azobenzene loading in the MOF to enhance the CO2/N2 separation performance since it can improve the separation performance that could not be obtained in non-functionalized fillers.
li S, Prasetya N, Ladewig BP, Investigation of Azo-COP-2 as a photo-responsive low-energy CO2 adsorbent and porous filler in mixed matrix membranes for CO2/N2 separation, Industrial & Engineering Chemistry Research, ISSN: 0888-5885
Azo-COP-2 is a nanoporous polymer with exceptional CO2/N2 separation performance. In this study, we further investigate the application of Azo-COP-2 as a low-energy CO2 adsorbent and porous filler in mixed matrix membranes (MMMs) for CO2/N2 separation. As an adsorbent, the UV-irradiated Azo-COP-2 showed lower CO2 uptake than in the nonirradiated state, and Azo-COP-2 also exhibited highly efficient CO2 photoswitching between the two states. Combined with high CO2/N2 selectivity, this makes Azo-COP-2 an excellent candidate for low-energy CO2 capture and release. Azo-COP-2 is also shown to be a beneficial filler in MMMs. For polysulfone-based MMMs, the CO2 permeability and CO2/N2 selectivity could be increased up to 160% and 66.7%, respectively. The strategy shows the great potential of Azo-COP-2 not only for a low-energy CO2 adsorbent but also to improve the performance of conventional polymeric membranes for CO2 postcombustion capture.
Boer SA, White KF, Slater B, et al., 2019, A multifunctional, charge-neutral, chiral ‘octahedral’ M12L12 cage, Chemistry - A European Journal, ISSN: 0947-6539
A chiral, octahedral M12L12 cage, which is charge neutral and contains an internal void of about 2000 Å3, is reported. The cage was synthesised as an enantiopure complex by virtue of amino‐acid‐based dicarboxylate ligands, which assemble around copper paddlewheels at the vertices of the octahedron. The cage persists in solution with retention of the fluorescence properties of the parent acid. The solid‐state structure contains large pores both within and between the cages, and displays permanent porosity for the sorption of gases with retention of crystallinity. Initial tests show some enantioselectivity of the cage towards guests in solution.
Chen C, Ozcan A, Yazaydin AO, et al., 2019, Gas permeation through single-crystal ZIF-8 membranes, Journal of Membrane Science, Vol: 575, Pages: 209-219, ISSN: 0376-7388
Grain boundaries are an unavoidable microstructural feature in intergrown polycrystalline metal-organic framework (MOF) membranes. They have been suspected to be less size-selective than a MOF's micropores, resulting in suboptimal separation performances – a speculation recently confirmed by transmission electron microscopy of MOF ZIF-8. Single-crystal membranes, without grain boundaries, should confine mass transport to micropores and reflect the intrinsic selectivity of the porous material. Here, we demonstrate the feasibility of fabricating single-crystal MOF membranes and directly measuring gas permeability through such a membrane using ZIF-8 as an exemplary MOF. Our single-crystal ZIF-8 membranes achieved ideal selectivities up to 28.9, 10.0, 40.1 and 3.6 for gas pairs CO2/N2, CO2/CH4, He/CH4 and CH4/N2 respectively, much higher than or reversely selective to over 20 polycrystalline ZIF-8 membranes, unequivocally proving the non-selectivity of grain boundaries. The permeability trend obtained in single-crystal membranes aligned with a force field that had been validated against multiple empirical adsorption isotherms.
Prasetya N, Ladewig B, 2018, A new Azo-DMOF-1 MOF as a photo-responsive low-energy CO2 adsorbent and its exceptional CO2/N2 separation performance in mixed matrix membranes, ACS Applied Materials and Interfaces, Vol: 10, Pages: 34291-34301, ISSN: 1944-8244
A new generation-2 light-responsive metal–organic framework (MOF) has been successfully synthesized using Zn as the metal source and both 2-phenyldiazenyl terephthalic acid and 1,4-diazabicyclo[2.2.2]octane (DABCO) as the ligands. It was found that Zn-azo-dabco MOF (Azo-DMOF-1) exhibited a photoresponsive CO2 adsorption both in static and dynamic condition because of the presence of azobenzene functionalities from the ligand. Further application of this MOF was evaluated by incorporating it as a filler in a mixed matrix membrane for CO2/N2 gas separation. Matrimid and polymer of intrinsic microporosity-1 (PIM-1) were used as the polymer matrix. It was found that Azo-DMOF-1 could enhance both the CO2 permeability and selectivity of the pristine polymer. In particular, the Azo-DMOF-1–PIM-1 composite membranes have shown a promising performance that surpassed the 2008 Robeson Upper Bound.
Prasetya N, Donose B, Ladewig BP, 2018, A new and highly robust light-responsive Azo-UiO-66 for highly selective and low energy post-combustion CO₂ capture and its application in a mixed matrix membrane for CO₂/N₂ separation, Journal of Materials Chemistry A, Vol: 6, Pages: 16390-16402, ISSN: 2050-7496
A new and robust generation-2 light-responsive MOF with UiO-66 topology applicable for post combustion CO2 capture has been successfully synthesized and is described in this article. Azo-UiO-66 shows a satisfactory performance for CO2/N2 separation as observed through high CO2/N2 selectivity. Furthermore, due to the presence of azobenzene groups, Azo-UiO-66 also exhibits a very efficient CO2 photoswitching uptake, a characteristic that has never been observed in any generation-2 light-responsive MOF. Combined together with its robust character, this makes Azo-UiO-66 a promising candidate for highly selective and low energy CO2 capture applications. To further apply this material, Azo-UiO-66 was incorporated in Matrimid to form mixed matrix membranes (MMM). Composites with up to 20 wt% of Azo-UiO-66 were fabricated and tested. The resulting MMM showed increased performance in terms of CO2 permeability and CO2/N2 selectivity compared with the similar MOF-based MMM composites. This then shows another promising application of Azo-UiO-66 as a filler to enhance polymeric membrane performance for CO2 separation.
Hagesteijn KFL, Jiang S, Ladewig BP, 2018, A review of the synthesis and characterization of anion exchange membranes, Journal of Materials Science, Vol: 53, Pages: 11131-11150, ISSN: 0022-2461
This review highlights advancements made in anion exchange membrane (AEM) head groups, polymer structures and membrane synthesis methods. Limitations of current analytical techniques for characterizing AEMs are also discussed. AEM research is primarily driven by the need to develop suitable AEMs for the high-pH and high-temperature environments in anion exchange membrane fuel cells and anion exchange membrane water electrolysis applications. AEM head groups can be broadly classified as nitrogen based (e.g. quaternary ammonium), nitrogen free (e.g. phosphonium) and metal cations (e.g. ruthenium). Metal cation head groups show great promise for AEM due to their high stability and high valency. Through “rational polymer architecture”, it is possible to synthesize AEMs with ion channels and improved chemical stability. Heterogeneous membranes using porous supports or inorganic nanoparticles show great promise due to the ability to tune membrane characteristics based on the ratio of polymer to porous support or nanoparticles. Future research should investigate consolidating advancements in AEM head groups with an optimized polymer structure in heterogeneous membranes to bring together the valuable characteristics gained from using head groups with improved chemical stability, with the benefits of a polymer structure with ion channels and improved membrane properties from using a porous support or nanoparticles.
Jiang S, Hagesteijn K, Ni J, et al., 2018, A scientometric study of the research on ion exchange membranes, RSC Advances, Vol: 8, Pages: 24036-24048, ISSN: 2046-2069
A comprehensive scientometric approach was adopted to study the research on ion exchange membranes. The statistical analysis was conducted based on 21 123 publications which were related to the topic of ion exchange membranes. Specifically, from 2001 to 2016, over 18 000 articles were published on ion exchange membranes, indicating researchers' great interest in this topic. Especially, compared to 2001, the number of articles published in 2016 increased approximately six-fold. This trend continued in 2017 since over 2000 articles were published in the year of 2017. Also, these articles were spread across over 1000 different journals, near 100 countries/regions and over 5000 research institutes, revealing the importance of ion exchange membrane as well as the broad research interest in this field. Besides, the properties and applications of ion exchange membranes were also discussed statistically. Furthermore, keywords analysis indicated that fuel cell and proton exchange membrane had the highest cooccurrence frequency. Finally, research areas analysis revealed that ion exchange membranes had a close relation with chemistry, energy and materials.
Prasetya N, Teck A, Ladewig BP, 2018, Matrimid-JUC-62 and Matrimid-PCN-250 mixed matrix membranes displaying light-responsive gas separation and beneficial ageing characteristics for CO2/N2 separation, Scientific Reports, Vol: 8, ISSN: 2045-2322
The performance of two generation-3 light-responsive metal-organic framework (MOF), namely JUC-62 and PCN-250, was investigated in a mixed matrix membrane (MMM) form. Both of them were incorporated inside the matrimid as the polymer matrix. Using our custom-designed membrane testing cell, it was observed that the MMMs showed up to 9% difference in CO2 permeability between its pristine and UV-irradiated condition. This shows that the light-responsive ability of the light-responsive MOFs could still be maintained. Thus, this finding is applicable in designing a smart material. Apart from that, the MMMs also has the potential to be applied for post-combustion carbon capture. At loadings up to 15 wt%, both CO2 permeability and CO2/N2 ideal selectivity could be significantly improved and surpassed the value exhibited by most of the MOF-matrimid MMM. Lastly the long term performance of the MMM was also evaluated and it was observed that both MMM could maintain their performance up to 1 month with only a slight decrease in CO2 permeability observed for 10 wt% PCN-250-matrimid. This study then opens up the possibility to fabricate a novel anti-aging multifunctional membrane material that is applicable as a smart material and also in post combustion carbon capture applications.
Slater B, Wang Z, Jiang S, et al., 2017, Missing Linker Defects in a Homochiral Metal-Organic Framework: Tuning the Chiral Separation Capacity, Journal of the American Chemical Society, Vol: 139, Pages: 18322-18327, ISSN: 1520-5126
Efficient chiral separation remains a very challenging task due to the identical physical and chemical properties of the enantiomers of a molecule. Enantiomers only behave differently from each other in the presence of other chiral species. Homochiral metal–organic frameworks (MOFs) have received much attention for their promising enantioseparation properties. However, there are still challenges to overcome in this field such as high enantiomeric separation. Structural defects play an important role in the properties of MOFs and can significantly change the pore architecture. In this work, we introduced missing linker defects into a homochiral metal–organic framework [Zn2(bdc)(l-lac)(dmf)] (ZnBLD; bdc = 1,4-benzenedicarboxylic acid, l-lac = l-lactic acid, dmf = N,N′-dimethylformamide) and observed an increase in enantiomeric excess for 1-phenylethanol of 35% with the defective frameworks. We adjusted the concentration of monocarboxylic acid ligand l-lactic acid by varying the ratio of Zn2+ to ligand from 0.5 to 0.85 mmol. Additionally, a defective framework was synthesized with propanoic acid as modulator. In order to elucidate the correlation between defects and enantiomeric excess, five characterization techniques (FTIR, TGA, 1H NMR, ICP, and PXRD) were employed. Full width at half-maximum analysis (fwhm) was performed on the powder X-ray diffraction traces and showed that the higher concentration of monocarboxylic acid MOFs were isostructural but suffered from increased fwhm values.
Ladewig BP, Prasetya N, 2017, Dynamic photo-switching in light-responsive JUC-62 for CO2 capture, Scientific Reports, Vol: 7, ISSN: 2045-2322
In this paper, we demonstrate the highly efcient photo-switching ability of a Cu-azobenzenetetracarboxylate MOF (JUC-62) for low-energy CO2 capture. Under UV light irradiation, both at 273and 298K, JUC-62 showed 51% and 34% lower CO2 uptake, respectively, than when UV light was of.Its dynamic CO2 uptake also matched well with its static condition. Storing it at ambient condition wasalso found not to destroy its framework structure and its dynamic photoswitching property could still bemaintained.
Ladewig BP, jiang S, 2017, High ion-exchange capacity semi-homogeneous cation exchange membranes prepared via a novel polymerization and sulfonation approach in porous polypropylene, ACS Applied Materials and Interfaces, Vol: 9, Pages: 38612-38620, ISSN: 1944-8244
Semi-homogeneous cation exchange membranes with superior ion exchange capacity (IEC) were synthesized via a novel polymerization and sulfonation approach in porous polypropylene support. The IEC of membranes could reach up to 3 mmol/g, due to high mass ratio of functional polymer to membrane support. Especially, theoretical IEC threshold value agreed well with experimental threshold value, indicating that IEC could be specifically designed without carrying out extensive experiments. Also, sulfonate groups were distributed both on membrane surface and across the membranes, which corresponded well with high IEC of the synthesized membranes. Besides, the semi-finished membrane showed hydrophobic property due to formation of polystyrene. In contrast, the final membranes demonstrated super hydrophilic property, indicating the adequate sulfonation of polystyrene. Furthermore, when sulfonation reaction time increased, the conductivity of membranes also showed a tendency to increase, revealing the positive relationship between conductivity and IEC. Finally, the final membranes showed sufficient thermal stability for electrodialysis applications such as water desalination.
Smith SJD, Konstas K, Lau CH, et al., 2017, Post-synthetic annealing: linker self-exchange in UiO-66 and its effect on polymer-MOF interaction, Crystal Growth & Design, Vol: 17, Pages: 4384-4392, ISSN: 1528-7505
Post-synthetic exchange (PSE) and defect engineering have emerged as powerful techniques for tuning the properties and introducing novel functionality to metal organic frameworks (MOFs). Growing evidence suggests that each technique plays a key role in the mechanism of the other: linker coordination chemistry is pivotal to defective frameworks, while defect sites can help initiate PSE. Here, the intersection of these approaches is explored by exchanging an MOF with linkers already present within the framework. Post-synthetic annealing (PSA) modifies an MOF’s properties by redistributing the framework’s mixture of bound linker/modulator species. Using changes to the polymer-additive interactions in poly-1-trimethylsilyl-1-propyne nanocomposites observed through aging, we demonstrate that PSA causes one linker species to preferentially accumulate on the MOF’s crystal surface. Reaction conditions are shown to affect molecular composition of the resulting annealed UiO-66 MOFs, a finding explained through established reaction constants. This work simultaneously reveals intricacies of post-synthetic modification chemistry and presents a facile means of tuning MOFs and MOF nanocomposites.
Abbasi Z, Shamsaei E, Fang X-Y, et al., 2017, Simple fabrication of zeolitic imidazolate framework ZIF-8/polymer composite beads by phase inversion method for efficient oil sorption, JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 493, Pages: 150-161, ISSN: 0021-9797
Ladewig BP, Jiang S, Li Y, 2017, A review of reverse osmosis membrane fouling and control strategies, Science of the Total Environment, Vol: 595, Pages: 567-583, ISSN: 0048-9697
Reverse osmosis (RO) membrane technology is one of the most important technologies for water treatment. However, membrane fouling is an inevitable issue. Membrane fouling leads to higher operating pressure, flux decline, frequent chemical cleaning and shorter membrane life. This paper reviews membrane fouling types and fouling control strategies, with a focus on the latest developments. The fundamentals of fouling are discussed in detail, including biofouling, organic fouling, inorganic scaling and colloidal fouling. Furthermore, fouling mitigation technologies are also discussed comprehensively. Pretreatment is widely used in practice to reduce the burden for the following RO operation while real time monitoring of RO has the advantage and potential of providing support for effective and efficient cleaning. Surface modification could slow down membrane fouling by changing surface properties such as surface smoothness and hydrophilicity, while novel membrane materials and synthesis processes build a promising future for the next generation of RO membranes with big advancements in fouling resistance. Especially in this review paper, statistical analysis is conducted where appropriate to reveal the research interests in RO fouling and control.
Saleha WFG, Ramesh R, Nalajala N, et al., 2017, Dielectric relaxations in phosphoric acid-doped poly(2, 5-benzimidazole) and its composite membranes, Journal of Applied Polymer Science, Vol: 134, ISSN: 1097-4628
Poly(2,5-benzimidazole) (ABPBI)—a promising high-temperature polymer electrolyte membrane—is characterized over a wide range of temperature (−50 to 220 °C) using broadband dielectric spectroscopy (BDS) to understand the various relaxation processes. The undoped ABPBI membrane shows two major secondary relaxations and a primary α relaxation. The effect of phosphoric acid (PA) and phosphotungstic acid grafted zirconium dioxide (PWA/ZrO2) nanoparticles on the chain relaxation and the proton conductivity is investigated. The phosphoric acid alters the relaxation trends, increases the number of free ions in the polymer matrix, and therefore the conductivity. The shift in the peak frequencies of different chain relaxation processes in the presence of PA and PWA/ZrO2 is attributed to the increase in free volume and the consequent easy motion of the polymer chains. The Fourier transform infra-red (FTIR) spectroscopy of ABPBI and the acid-doped composites show all the relevant peaks corresponding to C[DOUBLE BOND]C, C[DOUBLE BOND]N stretching, and phosphoric acid/phosphates, confirming the formation of ABPBI and doping with PA. The proton conductivity of the membranes is estimated from electrochemical impedance spectroscopy (EIS). To establish the effect of change in crystallinity on relaxations and proton conductivity, the undoped and PA-doped membranes are characterized using thermogravimetric analysis and in situ XRD at high temperatures.
Saleha WFG, Ramesh R, Naresh N, et al., 2017, Broadband dielectric spectroscopy of Nafion-117, sulfonated polysulfone (sPSF) and sulfonated polyether ketone (sPEK) membranes, Journal of Applied Polymer Science, Vol: 134, ISSN: 1097-4628
Nafion®-117, sulfonated polysulfone (sPSF) and sulfonated polyetherketone (sPEK) arecharacterized using broadband dielectric spectroscopy in the frequency range of 10 MHz–100mHz. Overall, there are 4-5 relaxation processes in these sulfonated membranes and acomparison of their spectral features allows assigning the relaxation processes. At an optimumamplitude of ~100 mVrms, all the relaxations are clearly defined as the electrode polarization isminimized. At low temperatures (-130°C), these membranes show a broad relaxation peak in themid-frequency region, which quickly shifts towards the high-frequency region as the temperatureis increased to -90°C. This peak is observed in proton exchange membranes for the first time dueto the use of low ac amplitude, and it is assigned to the relaxation of the confined water in themicro-pores. With all the membranes, the peak associated with -SO3H group relaxation isobserved in the same frequency range at a temperature of ~-80°C.
Al-Shaeli M, Smith SJD, Shamsaei E, et al., Highly fouling-resistant brominated poly (phenylene oxide) membranes using surface grafted diethylenetriamine, RSC Advances, Vol: 7, Pages: 37324-37330, ISSN: 2046-2069
Hydrophilic bromomethylated poly(phenylene oxide) (BPPO) ultrafiltration membranes were prepared via a single-step reaction with diethylenetriamine (DETA). The resulting DETA modified BPPO membranes are characterised using FTIR-ATR, SEM, fouling resistance, filtration test and contact angle measurements. Although permeation flux was adversely affected, the chemically bound DETA leads to a significant increase in surface hydrophilicity and anti-fouling properties of BPPO/DETA membranes. The composite BPPO/DETA membranes show a considerable reduction in membrane fouling and enhanced BSA rejection, with foulants easily removed by normal cleaning methods. Herein, a facile surface modification with DETA is shown to be an effective means of enhancing the flux recovery ratio and anti-fouling properties of BPPO membranes.
Abbasi Z, Shamsaei E, Leong SK, et al., 2016, Effect of carbonization temperature on adsorption property of ZIF-8 derived nanoporous carbon for water treatment, Microporous and Mesoporous Materials, Vol: 236, Pages: 28-37, ISSN: 1387-1811
The heat treatment effect on the adsorption capabilities of nanoporous carbon particlesderived from Zeolitic Imidazolate Framework-8 (ZIF-8) was investigated at 600, 1000 and1200 ̊C in this study. The results showed that heat treatment at 1000 ̊C had a significant effecton the adsorption capacity of ZIF-8 (almost 10 times) for the removal of methylene blue(MB) dye from water. Nanoporous carbons were synthesized by direct carbonization of ZIF-8. SEM and TEM images showed that the carbon resulting from ZIF-8 carbonization atvarious temperatures retained the original structure and morphology of ZIF-8. The carbonnanoparticles carbonized at 1000 ̊C exhibited outstanding adsorption capacities (186.3 mg/g)compared to nanoparticles carbonized at 600 ̊C (49.5 mg/g) and 1200 ̊C (36.7 mg/g) as wellas ZIF-8 (19.5 mg/g) due to the change in surface charge and pore size distribution. Thesurface functionalities of materials were also characterized by Raman Spectroscopy, N2 adsorption-desorption, FTIR and TGA. The surface charge of the carbon particles changedfrom positive (ZIF-8) to negative as a result of conversion to carbon confirmed by zetapotential of the samples. The ZIF-8 derived carbon nanoparticles were found to be efficientadsorbents for water treatment purposes due to the satisfactory adsorption properties such ashigh adsorption capacity and good wettability.
Ladewig BP, 2016, Physical aging in glassy mixed matrix membranes; tuning particle interaction for mechanically robust nanocomposite films, Journal of Materials Chemistry A, Vol: 4, Pages: 10627-10634, ISSN: 2050-7496
Despite the exceptional separation performance of modern glassy mixed matrix membranes, these materials are not being utilized to improve the performance of existing membrane technologies. Nano-sized additives can greatly enhance separation performance, and have recently been used to overcome age-related performance loss of high performance MMMs. However nano-additives also compromise the structural integrity of films and little is known on how physical aging affects their mechanical properties over time. A solution for both physical aging and mechanical instability is required before these high performance materials can be utilised in industrial membrane applications. Here, we examine physical aging in mixed matrix membranes through mechanical properties and gas permeation experiments using three glassy polymers, Matrimid® 5218, poly-1-trimethylsilyl-1-propyne (PTMSP), and a Polymer of Intrinsic Microporosity (PIM-1); and a range of nano-scale additives previously shown to enhance gas separation performance. We find polymer-additive interactions strongly influence local physical aging and play a key role in determining the overall material properties of glassy nanocomposite films. Strong interface interactions can slow physical aging, and may not correlate to reinforced or age-stable films. Whereas traditionally ‘incompatible’ nanocomposites exhibit mechanical properties that can improve over time and even outperform their native polymers. Tuning polymer-additive interactions is vital to achieving the physical aging, mechanical stability, and permselectivity requirements of advanced mixed matrix membrane technologies and reducing the enormous global energy cost of separation processes.
Leong J, Tan J, Heitz A, et al., 2016, Use of vibratory shear enhanced processing to treat magnetic ion exchange concentrate: A techno-economic analysis, Desalination, Vol: 383, Pages: 46-52, ISSN: 1873-4464
Disposal of waste generated by inland water treatment technologies is highly expensive. The introduction of vibratory shear enhanced processing (VSEP) to treat waste produced from magnetic ion exchange (MIEX) shows benefits in terms of performance and economics. A small VSEP unit fitted with a nanofiltration (NF) membrane is capable of treating up to 15 kL of MIEX waste per day, is able remove more than 97% of dissolved organic compounds as well as recover over 80% of waste in the form of permeate. The reuse of permeate to makeup brine has seen significant reductions in salt consumption and waste disposal at Wanneroo Groundwater Treatment Plant (GWTP). During the first year of VSEP operation, salt consumption reduced by 42% and waste disposal was projected to reduce by 23.9%. Further improvements in both cost categories were observed in the second year of operation and considering the same trend is followed, the payback period of the project will occur between the 6th and 7th year of operation for discounted analysis and has a positive net present value.
Lyndon R, Konstas K, Thornton AW, et al., 2015, Visible Light-Triggered Capture and Release of CO2 from Stable Metal Organic Frameworks, CHEMISTRY OF MATERIALS, Vol: 27, Pages: 7882-7888, ISSN: 0897-4756
Asquith BM, Meier-Haack J, Ladewig BP, 2015, Poly(arylene ether sulfone) copolymers as binders for capacitive deionization activated carbon electrodes, CHEMICAL ENGINEERING RESEARCH & DESIGN, Vol: 104, Pages: 81-91, ISSN: 0263-8762
Lyndon R, Konstas K, Evans RA, et al., 2015, Tunable Photodynamic Switching of DArE@PAF-1 for Carbon Capture, Advanced Functional Materials, Vol: 25, Pages: 4405-4411, ISSN: 1616-3028
A new type of photodynamic carbon capture material with up to 26 wt% CO2 desorption capacity is synthesized via incorporation of diarylethene (DArE) as guest molecules in porous aromatic framework-1 (PAF-1). In these host–guest complexes, the carboxylic acid groups featured in DArE allow multiple noncovalent interactions to exist. DArE loadings ranging from 1 to 50 wt% are incorporated in PAF-1 and the complexes characterized by UV–vis spectroscopy, FT-IR spectroscopy, CO2, and N2 adsorption. Successful inclusion of DArE in PAF-1 is indicated by the reduction of pore size distributions and an optimum loading of 5 wt% is determined by comparing the percentage photoresponse and CO2 uptake capacity at 1 bar. Mechanistic studies suggest that photoswitching modulates the binding affinity between DArE and CO2 toward the host, triggering carbon capture and release. This is the first known example of photodynamic carbon capture and release in a PAF.
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