Mohamad Azmi Bustam

Dissolution and Delignification of Bamboo Biomass Using Amino Acid-Based Ionic Liquid

In the present work, the dissolution of bamboo biomass was tested using a number of ionic liquids synthesized in laboratory. It was observed that one of the synthesized amino acid-based ionic liquids, namely 1-ethyl-3-methylimidazolium glycinate, was capable of dissolving the biomass completely. The dissolved biomass was then regenerated using a reconstitute solvent (acetone/water) and was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results were compared to preconditioned bamboo biomass. The regenerated biomass was found to have a more homogenous macrostructure, which indicates that the crystalline form and structure of its cellulose has changed from type Ι to type ΙΙ during the dissolution and regeneration process.

Effect of sulfonate-based anions on the physicochemical properties of 1-alkyl-3-propanenitrile imidazolium ionic liquids

In this paper, the physicochemical properties of a new series of ionic liquids (ILs) based on nitrile-functionalised imidazolium cations ([C2CN Cnim]+) with sulfonate-based anions were studied. The ILs were prepared by reacting imidazole with acrylonitrile, followed by butyl- and decyl bromide. The anions of the resulting bromide salts exchanged by metathesis to dioctylsulfosuccinate (DOSS), dodecylsulfate (DDS), benzenesulfonate (BS) and trifluoromethanesulfonate (TFMS). The densities of these ILs are lower compared to the those of other reported nitrile-functionalised ILs, while on the other hand, the viscosities of the ILs are higher due to the effects of the large anions and the long alkyl chain of the cations.

Some Studies on the Synthesis and Characterization of Carbon Aerogel

Porous carbon aerogels were synthesized from resorcinol-formaldehyde monomers using acetic acid, sodium carbonate and sodium hydroxide catalysts. The synthesized aerogels were characterized by XRD, TGA, SEM, BET and FTIR. The carbon aerogel developed by acetic acid catalyst produced a very high surface area (619.26 m2.g−1). All the different catalysis resulted in different surface morphology of the aerogels. The synthesized carbon aerogels contained significant amount of hydroxyl, carboxyl groups and different types of C-C linkages. These aerogels exhibited potential as adsorbents for removal of toxic materials and heavy metals.

Efficient conversion of lignocellulosic biomass to levulinic acid using acidic ionic liquids

In the present research work, dicationic ionic liquids, containing 1,4-bis(3-methylimidazolium-1-yl) butane ([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 levulinic acid (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 110°C for 60min, 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 LA from agro-waste will open new opportunity for the conversion of sustainable biomass resources into valuable chemicals.

Photocatalytic Degradation of DIPA Using Bimetallic Cu-Ni/TiO2 Photocatalyst under Visible Light Irradiation

Bimetallic Cu-Ni/TiO2 photocatalysts were synthesized using wet impregnation (WI) method with TiO2 (Degussa-P25) as support and calcined at different temperatures (180, 200, and 300°C) for the photodegradation of DIPA under visible light. The photocatalysts were characterized using TGA, FESEM, UV-Vis diffuse reflectance spectroscopy, fourier transform infrared spectroscopy (FTIR) and temperature programmed reduction (TPR). The results from the photodegradation experiments revealed that the Cu-Ni/TiO2 photocatalysts exhibited much higher photocatalytic activities compared to bare TiO2. It was found that photocatalyst calcined at 200°C had the highest photocatalyst activities with highest chemical oxygen demand (COD) removal (86.82%). According to the structural and surface analysis, the enhanced photocatalytic activity could be attributed to its strong absorption into the visible region and high metal dispersion.

Optimized TiO2 Nanocrystallites Aggregates for Enhanced Efficiency in Dye Solar Cells

TiO2 aggregates-based dye solar cells (DSCs) have gained an increasing attention due to their enhanced harvesting of light radiance. The capability of this photoelectrode material is attributed to the submicron spherical aggregates that introduce light scattering effect which can generate more electrons whilst high internal surface area for dye chemisorption is provided by nanocrystallites which made up the aggregates. Here, TiO2 aggregates (0.45-0.20 μm) composing of nanocrystallites (10-28 nm) with desired physicochemical properties for enhanced overall light conversion efficiency of DSC were synthesized by varying the water content in the hydrolysis of titanium alkoxide in ethanol and calcination temperature. TiO2 aggregates obtained were characterized using FESEM, XRD and UV-Vis spectroscopy. The assembled DSCs were then evaluated using solar simulator under AM 1.5 (100 mW/cm2) simulated sunlight. With higher water content in the hydrolysis process, the aggregates reduce in size and lose their spherical shapes resulting in lower absorption intensity indicating the occurrence of low light scattering in the TiO2 film. Nanocrystallites were found to have an increasing size of 12 nm to 28 nm with increasing calcination temperature of 400°C to 700°C. Sample of aggregates calcined at 450°C recorded the highest efficiency (~4%). Highest conversion efficiency was observed for DSC that used well-defined spherical TiO2 aggregates composing of nanocrystallites which were synthesized at optimum synthesis parameter which is by using ethanol with low water content (0.9 vol%) followed by calcination at 450°C. Thus, optimized TiO2 nanocrystallites which form spherical aggregate is critical in order to improve light harvesting efficiency of DSCs.

Solubility Parameters Based on Refractive Index Data of Ionic Liquid

This article reports on the estimation of solubility parameters using refractive index for a series of imidazolium-based ionic liquids (ILs) and their dependencies on the carbon number of alkyl side-chain of cation and anion. Gathering about 35 ILs of refractive indices data from the literature, the solubility parameters estimation fit well with the suggested correlation. The precision of the estimated solubility parameters obtained indicates that the refractive index-solubility parameters correlation can be an alternative tool to estimate solubility parameter value for ILs.

Volumetric properties of binary mixtures of benzene with cyano-based ionic liquids

The objective of this study is to investigate the volumetric properties of the binary mixtures comprised benzene and two ionic liquids, 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) and 1-butyl-3-methyl- imidazolium dicyanamide ([BMIM][N(CN)2](. Densities (ρ) and viscosities (μ) of the binary mixtures were measured over a temperature range of 293.15 to 323.15 K and at atmospheric pressure. Excess molar volumes and viscosity deviations were calculated from the experimental densities and viscosities values. The volumetric properties of the mixtures were changed significantly with the change of compositions and temperatures. It was also found that the value of excess molar volume and viscosity deviations were negative (-ve) over the entire range of compositions. The results have been interpreted in terms of molecular interactions of ILs and benzene.

Electrochemical Performance of Cathode LiVOPO4 Doped with Mo and W

Molybdenum (Mo) and tungsten (W) substituted LiV0.99X0.01OPO4 (X = Mo and W) compounds were synthesized by impregnation method. The structures of samples were characterized by X-ray diffraction, and their electrochemical properties were studied by using charge-discharge in galavanostatic mode versus Li+/Li. The electrical conductivity of the samples was estimated by using impedance spectroscopy measurement with 2 point probe method at room temperature. Phosphates of composition LiV0.99X0.01OPO4 with 1% Mo and W content in the structure exhibits high intercalation potential of 3.95 V versus Li/Li+. It was found that the electrical conductivity of Mo and W substituted samples at room temperature was improved to 4.8 × 10–6 and 1.5 × 10–5 S.cm–1, respectively. Discharge capacity was also observed for the W doped sample with good retention performance up to 20 cycles at high current density of C/5 (0.4 mA.cm–2).

Investigation on Aromaticity Index and Double-Bond Equivalent of Aromatic Compounds and Ionic Liquids for Fuel Desulphurization

Aromaticity index (AI) and double-bond equivalent (DBE) were studied to seek a simpler approach in identifying suitable ionic liquids for the desulphurization process. Manifestation of interaction mechanism by COSMO-RS and Raman spectroscopy is discussed. The findings demonstrate that AI and DBE calculations can be used to analyze and arrogate potential combination of cation and anion for fuel desulphurization purposes.