| 1. |
- Hamzah, Wan Suzaini Wan, et al.
(författare)
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Microwave-assisted chemistry : parametric optimization for catalytic degradation of lignin model compounds in imidazolium-based ILs
- 2021
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Ingår i: Biomass Conversion and Biorefinery. - : Springer Berlin/Heidelberg. - 2190-6815 .- 2190-6823.
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Tidskriftsartikel (refereegranskat)abstract
- Lignin, a readily available form of biomass with a potential source of aromatic chemical compounds, has not been fully utilized due to its complex structure. Hence, this study aims to elaborate and optimize the effects of parametric microwave conditions for the catalytic degradation of lignin model compounds. In addition to that, 41 types of imidazolium-based Ionic liquids were employed for the conversion of lignin model compounds such as guaiacol and benzyl phenyl ether. The microwave-assisted conversion of lignin model compounds in imidazolium-based ionic liquids was performed at optimum applied microwave power 700 W and 30-min irradiation time. The percentages conversion and yield were quantified using high-performance liquid chromatography (HPLC) analysis. Results revealed that the chloride anion-based ionic liquids exhibited better nucleophilic behavior and catalyzed the cleavage of ether-based compounds efficiently under microwave irradiation. Among the imidazolium-based ionic liquids, 1H-methylimidazolium chloride ([1H-MIM][Cl]) exhibited better performance with guaiacol conversion and catechol yield of 99% and 81%, respectively. Therefore, the microwave-assisted technique was found to be more promising than conventional methods for the ionic liquid-based catalytic degradation of lignin model compounds.
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| 2. |
- Idris, Alamin, et al.
(författare)
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Effect of silane coupling agents on properties and performance of polycarbonate/silica MMMs
- 2019
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Ingår i: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 73, s. 159-170
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Tidskriftsartikel (refereegranskat)abstract
- The choice of amine terminated silanes remain scarce although they have been used as coupling agents to enhance silica dispersion and interaction in polymer matrix. Functionalized silica particles were synthesized by co-condensing tetraethyl-orthosilicate with four types of silane agents in sol-gel process. These particles were characterized and incorporated into polycarbonate polymer matrix. The morphology, structure, thermal stability, mechanical strength and gas (N2, CH4, CO2) permeation properties of mixed matrix membranes (MMMs) were characterized by standard techniques. The functionalized silica particles were of various particle sizes and extent of functionalization. PC/Silica MMM produced by incorporating functionalized silica particles using (3-aminopropyl) trimethoxysilane exhibited better morphology. The corresponding MMM performance has improved (αCO2/N2 = 42.8 and αCO2/CH4 = 38) as compared to pure PC membrane (αCO2/N2 = 20.30 and αCO2/CH4 = 18.5) and other MMMs. Thus, low molecular weight single amine terminated silane agents are potential candidates for the development of PC/silica MMMs.
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| 3. |
- Idris, Alamin, et al.
(författare)
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Effects of Phase Separation Behavior on Morphology and Performance of Polycarbonate Membranes
- 2017
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Ingår i: Membranes. - : MDPI. - 2077-0375. ; 7:2, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- The phase separation behavior of bisphenol-A-polycarbonate (PC), dissolved in N-methyl-2-pyrrolidone and dichloromethane solvents in coagulant water, was studied by the cloud point method. The respective cloud point data were determined by titration against water at room temperature and the characteristic binodal curves for the ternary systems were plotted. Further, the physical properties such as viscosity, refractive index, and density of the solution were measured. The critical polymer concentrations were determined from the viscosity measurements. PC/NMP and PC/DCM membranes were fabricated by the dry-wet phase inversion technique and characterized for their morphology, structure, and thermal stability using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis, respectively. The membranes’ performances were tested for their permeance to CO2, CH4, and N2 gases at 24 ± 0.5 °C with varying feed pressures from 2 to 10 bar. The PC/DCM membranes appeared to be asymmetric dense membrane types with appreciable thermal stability, whereas the PC/NMP membranes were observed to be asymmetric with porous structures exhibiting 4.18% and 9.17% decrease in the initial and maximum degradation temperatures, respectively. The ideal CO2/N2 and CO2/CH4 selectivities of the PC/NMP membrane decreased with the increase in feed pressures, while for the PC/DCM membrane, the average ideal CO2/N2 and CO2/CH4 selectivities were found to be 25.1 ± 0.8 and 21.1 ± 0.6, respectively. Therefore, the PC/DCM membranes with dense morphologies are appropriate for gas separation applications.
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| 4. |
- Idris, Alamin, et al.
(författare)
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Grindability and abrasive behavior of coal blends : analysis and prediction
- 2019
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Ingår i: International Journal of Coal Preparation and Utilization. - : Taylor & Francis. - 1939-2699 .- 1939-2702. ; , s. 1-27
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Tidskriftsartikel (refereegranskat)abstract
- Low-grade coals are blended with high-quality coals to meet economic, environmental, and quality specifications. Hence, the grindability and abrasiveness of coal blends are crucial economic and operational parameters. This work evaluates, analyzes, and predicts the grindability and abrasive behavior of coal blends. Three binary coal blends with common low-grade coal were first prepared at various ratios. Blends 1 and 2 were composed of identical and similar ranks, whereas Blend 3 was composed of different ranks. The blends were analyzed using proximate, ultimate analyzers, and a Bomb calorimeter. The grindability and abrasive behavior of the blends were measured using Hardgrove grindability index (HGI) and Yancey, Geer, and Price methods, respectively. Further, the coarser (+75 mu m) and finer (-75 mu m) fractions of HGI experiment were characterized using proximate, ultimate and heating value analyses. The additivity of HGI values was observed for Blend 1 and Blend 2, whereas, the non-additive behavior was observed in Blend 3. Further, the blends' mineral matter contents and abrasiveness index were found to be additive. Several existing models were found to be inaccurate for HGI predictions. Therefore, a new cross-validated model using multi-linear regression was proposed. The model exhibited better HGI predictions of coal blends with a coefficient of determination R-2 = 0.9416.
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| 5. |
- Idris, Alamin, et al.
(författare)
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Investigation on particle properties and extent of functionalization of silica nanoparticles
- 2020
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 506
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Tidskriftsartikel (refereegranskat)abstract
- Quantification of the extent of functionalization on silica nanoparticle surface is crucial in a variety of applications. This work aims to evaluate particle properties and extent of functionalization on silica nanoparticles synthesized under acidic and basic conditions via co-condensation of tetraethyl orthosilicate with 3-aminopropyltrimethoxysilane in the sol-gel process. The silica nanoparticles properties were analyzed via field emission scanning electron microscope, transmission electron microscopy, dynamic light scattering, and Brunauer-Emmett-Teller methods; whereas, the extent of functionalization was evaluated using Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer, and thermogravimetric analyzer. Results showed that the functionalized silica nanoparticles have a lower tendency to agglomerate and highly monodispersed as compared to unfunctionalized. The surface areas of acid and base-catalyzed nanoparticles were obtained as 618.8 and 514.7 m2/g, respectively. FTIR spectra, XPS scans, and TGA curves confirmed the presence of alkyl and amine functional groups on the functionalized surfaces. The extent of functionalization (N/Si) was obtained as 0.296 and 0.196, and the percentages of functional groups attached on the surface were found to be 6.80 and 5.92% for acid and base-catalyzed nanoparticles, respectively. The overall results suggest that acidic catalysis is a better approach for the synthesis of surface-modified or organofunctionalized silica nanoparticles.
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| 6. |
- Idris, Alamin, et al.
(författare)
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Modified Bruggeman models for prediction of CO2 permeance in polycarbonate/silica nanocomposite membranes
- 2017
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Ingår i: The Canadian Journal of Chemical Engineering. - : John Wiley & Sons. - 0008-4034 .- 1939-019X. ; 95:12, s. 2398-2409
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Tidskriftsartikel (refereegranskat)abstract
- Abstract The polycarbonate membranes performances are improved by the incorporation of silica nanoparticles into the polymer matrix. Prepared PC/silica nanocomposite membranes with various silica content are considered and the experimental relative permeance of CO2 gas at 200 kPa (2 bar) feed pressure are used as reference in the predictions using the existing theoretical models such as Maxwell-Wagner-Sillar, Bruggeman, Lewis-Nielsen, Pal, and modified Pal models. TEM and BET analysis were used to characterize the silica nanoparticles; FESEM was used to characterize the morphology of the nanocomposite membranes. The TEM image of the silica nanoparticles reveals that the nanoparticles are mostly spherical. BET results reveal that the surface area and pore diameter of the silica nanoparticles are 618.8 m2/g and 0.28 nm, respectively. The existing models have resulted in poor predictions with errors AARE % of 26.52 to 28.02 %. Observation by FESEM image shows that the dispersed particles are surrounded by interfacial voids and rigidified polymer layer. Modified Bruggeman models that consider the interfacial volume show appreciable prediction with AARE 4.59 % being obtained with the pseudo-two-phase Bruggeman model. Moreover, when the model considered pseudo-three-phase morphology, the AARE % value reduced to 3.92 %. Thus, the contribution due to the interfacial rigidified layer was minimal.
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| 7. |
- Idris, Alamin, et al.
(författare)
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Modified Higuchi Model Applied to Permeation Prediction of Nanocomposite Membranes
- 2016
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Ingår i: Proceeding of 4th international conference on process engineering and advanced materials (ICPEAM 2016). - : Elsevier. ; , s. 208-214
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Konferensbidrag (refereegranskat)abstract
- In this work, the existing Higuchi models were used for the prediction of gas permeability through the nanocomposite membranes. Predicted values were compared with experimental results of permeability for polycarbonate/silica nanocomposite membranes. Based on the critical analysis of the models predictions and its deviations, the parameter that influences the permeation behavior has been identified. The results revealed that for any particular gas, the change of empirical Higuchi parameter exhibited a direct impact on the accuracy the model. Thus, a modified parameter was incorporated on the modified Higuchi model relating to the intrinsic properties of the penetrant gas. With the new proposed Higuchi model, appreciable predictions of gas permeability through polycarbonate/silica nanocomposite membranes were achieved. The calculated absolute average relative error for CO2, N2 and CH4 gas permeability were found to be 7.18%, 6.07%, and 6.14%, respectively. Their corresponding standard deviations were obtained as 2.53, 1.53 and 0.73 Comparing the existing Higuchi models predictions, the new proposed Higuchi model has resulted to a reduction in relative errors by 6.3% for CO2, 70.66% for N2, and 65.25% for CH4.
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| 8. |
- Idris, Alamin, et al.
(författare)
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Polycarbonate/silica nanocomposite membranes : Fabrication, characterization, and performance evaluation
- 2017
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Ingår i: Journal of Applied Polymer Science. - : John Wiley & Sons. - 0021-8995 .- 1097-4628. ; 134:38, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT Polycarbonate/silica nanocomposite membranes at low silica loading were fabricated by solution blending and solvent evaporation technique. The functionalized silica nanoparticles used were synthesized by co-condensing hydrolyzed tetraethylorthosilicate with 3-aminopropyl trimethoxysilane in the sol–gel process. The membranes morphology, composition, surface, structure, thermal and mechanical properties were analyzed by the standard characterization techniques. The gas permeation tests were conducted in four-channel permeation cells. Field emission scanning electron microscopy results reveal that membranes above 3 wt % silica content formed distinguishable voids and agglomerates. Fair distribution of silica nanoparticles and absence of residual solvents were observed by energy dispersive X-ray and thermogravimetric analysis. Fourier transform infrared spectroscopy spectra confirmed the presence of new functional groups (NH) and (OH) bonds. The X-ray diffraction pattern revealed the polymer-particle interactions, the formation of rigidified polymer chain, and nanostructured silicon crystals. Further, the thermogravimetric analysis results revealed thermal stability enhancement while differential scanning calorimetry results of increased glass transition temperatures confirmed the presence of rigidified polymer chain. Furthermore, enhancements in mechanical strength of the membranes were observed. Moreover, at all feed pressures, increased CO2, N2, and CH4 gas permeation was observed. At 6 bar feed pressure, the CO2/N2 and CO2/CH4 ideal selectivities of PC membranes with 3 wt % silica loading have increased from 19.2 to 38.0 and 29.2, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45310.
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| 9. |
- Khan, Amir Sada, et al.
(författare)
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Chapter 1 - Conversion of biomass to chemicals using ionic liquids
- 2020
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Ingår i: Green Sustainable Process for Chemical and Environmental Engineering and Science. - : Elsevier. ; , s. 1-30
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- From the conversion of lignocellulosic biomass to platform chemicals using ionic liquids (ILs), it was concluded that ILs have dual functions and can be used as catalyst and solvent for the synthesis of 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) from lignocellulosic biomass. The conversion of lignocellulosic biomass to chemicals depends upon the nature of feedstocks and structure of ILs. The yield of 5-HMF and LA from fructose and glucose is higher than cellulose and lignocellulose. Among the various available ILs, the acidic ionic liquids (AILs) such as [C3SO3Hmim][HSO4], [C4SO3Hmim][HSO4], [C3SO3Hmim][CH3SO3], [C3SO3Hmim][Cl], [C3SO3Hmim][CF3SO3], and [C3SO3HPy][HSO4] showed better yield of 5-HMF and LA. The imidazolium-based ILs that contain acidic functional group such HSO4 and Cl anion resulted in higher yield of LA and 5-5-HMF, respectively. Therefore it is essential to synthesize such ILs that have acidic functional group in their structure for the direct conversion of cellulose and lignocellulosic biomass to 5-HMF and LA.
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| 10. |
- Khan, Amir Sada, et al.
(författare)
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Efficient Conversion of Lignocellulosic Biomass to Levulinic Acid Using Acidic Ionic Liquids
- 2018
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 181, s. 208-214
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Tidskriftsartikel (refereegranskat)abstract
- In the present research work, dicationic ionic liquids, containing 1,1-Bis(3-methylimidazolium-1-yl) butylene ([C4(Mim)2]) cation with counter anions [(2HSO4)(H2SO4)0], [(2HSO4)(H2SO4)2] and [(2HSO4)(H2SO4)4] were synthesised. ILs structures were confirmed using 1H NMR spectroscopy. Thermal stability, Hammett acidity, density and viscosity of ILs were determined. Various types of lignocellulosic biomass such as rubber wood, palm oil frond, bamboo and rice husk were converted into LA. Among the synthesized ionic liquids, [C4(Mim)2][(2HSO4)(H2SO4)4] showed higher % yield of LA up to 47.52 from bamboo biomass at 100 °C for 60 min, which is the better yield at low temperature and short time compared to previous reports. Surface morphology, surface functional groups and thermal stability of bamboo before and after conversion into LA were studied using SEM, FTIR and TGA analysis, respectively. This one-pot production of levulinic acid from agro-waste will open new opportunity for the conversion of sustainable biomass resources into valuable chemicals.
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| 11. |
- Sarwono, Ariyanti, et al.
(författare)
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Alkyd paint removal : Ionic liquid vs volatile organic compound (VOC)
- 2018
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Ingår i: Progress in organic coatings. - : Elsevier. - 0300-9440 .- 1873-331X. ; 122, s. 79-87
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Tidskriftsartikel (refereegranskat)abstract
- The drive towards safer technology in removing paint from substrate requires switching from hazardous volatile organic compounds to greener alternative solvents. Ionic liquids (ILs) have been considered as relatively green solvents and employed in many applications. This study focusses on investigation of ILs as alternative green solvents for paint removal. In this regard, five imdazolium based ILs were studied for alkyd paint removal on coated wooden substrate. The effect of various anions such as dicyanamide [DCA], bis (trifluoromethanesulfonyl) imide [NTf2], hydrogen sulphate [HSO4], acetate [OAc] and chloride [Cl] was investigated. For benchmarking and comparison, three volatile organic solvents such as toluene, acetonitrile, and ethanol were used. Microscopic images showed that [DCA] anion gave significant impact on alkyd removal. In addition, [Bmim][DCA] gave highest swelling percentage of 23% whereas the other ILs did not show significant swelling. Viscosity, anion size and alkyd paint-IL interactions played important roles in removal efficacy. The prolonged immersion time in [Bmim][DCA] decreased the pull off adhesion strength up to 83.3% and consecutively promoted paint detachment from substrate. Similar infrared pattern of bare wooden stick and [Bmim][DCA] treated coated wooden stick indicates significant removal of paint by IL. The experimental results demonstrate promising application of IL as a green solvent for paint removal.
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| 12. |
- Sarwono, Ariyanti, et al.
(författare)
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Optimization of ionic liquid assisted sugar conversion and nanofiltration membrane separation for 5-hydroxymethylfurfural
- 2019
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Ingår i: Journal of Industrial and Engineering Chemistry. - : Elsevier. - 1226-086X .- 1876-794X. ; 69, s. 171-178
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides complete loop of ionic liquid (IL) assisted glucose conversion to 5-hydroxymethylfurfural (HMF), nanofiltration membrane (NF) based separation and recyclability. The optimum HMF yield of 65.6% was obtained with 8wt.% catalyst loading at 125°C reaction temperature in 120min reaction time. Ea for conversion was found to be 120kJ/mol. NF was adopted first time to separate IL and HMF. The percentage of recovered HMF using NF for 1st, 2nd and 3rd batches are 94.87, 84.35 and 71.65 respectively. The structures of regenerated IL and HMF, obtained from NF and liquid–liquid extraction, were confirmed by NMR.
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| 13. |
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| 14. |
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| 15. |
- Shafie, Siti Nur Alwani, et al.
(författare)
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[EMIM][Tf2N]-Modified Silica as Filler in Mixed Matrix Membrane for Carbon Dioxide Separation
- 2021
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Ingår i: Membranes. - : MDPI. - 2077-0375. ; 11:5, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on the effect of modified silica fillers by [EMIN][Tf2N] via physical adsorption on the CO2 separation performance of a mixed matrix membrane (MMM). The IL-modified silica was successfully synthesized as the presence of fluorine element was observed in both Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometer (XPS) analyses. The prepared MMMs with different loadings of the IL-modified silica were then compared with an unmodified silica counterpart and neat membrane. The morphology of IL-modified MMMs was observed to have insignificant changes, while polymer chains of were found to be slightly more flexible compared to their counterpart. At 2 bar of operating pressure, a significant increase in performance was observed with the incorporation of 3 wt% Sil-IL fillers compared to that of pure polycarbonate (PC). The permeability increased from 353 to 1151 Barrer while the CO2/CH4 selectivity increased from 20 to 76. The aforementioned increment also exceeded the Robeson upper bound. This indicates that the incorporation of fillers surface-modified with ionic liquid in an organic membrane is worth exploring for CO2 separation.
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