Carbon cryogel production from lignin, ionic liquid and liquefied oil palm frond as catalyst for esterification of levulinic acid

Carbon cryogel synthesized from lignin, ionic liquid (IL) and mixtures of liquefied oil palm frond-ionic liquid (LOPF-IL), was used as an acid catalyst for esterification of levulinic acid in ethanol. Commercial lignin was reacted with furfural via sol-gel poly-condensation reaction at 90 °C for 30 min and the gel was freeze-dried and finally carbonized or calcined to produce carbon cryogel. Parametric study for the gel preparation was conducted to evaluate the carbon cryogel surface area and acidity. Similar parametric study was also performed on gel synthesis from IL and furfural. The selected gel condition of IL and furfural was applied for gel preparation from LOPF-IL and furfural. Nitrogen physisorption and temperature programmed desorption of ammonia measurements revealed the selected carbon cryogels obtained a large total surface area (>200 m2/g) and high acidity (>10 mmol/g). The selected carbon cryogels from lignin-furfural (CCLF), IL-furfural (CCIL) and liquefied OPF-IL-furfural (CCOPF) were further characterized using thermogravimetric analyzer, Fourier transform infrared spectroscopy, x-ray diffraction and field emission scanning electron microscopy with energy dispersive x-ray spectrometry. The phase structure of the synthesized spherical carbon cryogel was amorphous, has micro structures (microspheres) and thermally stable. The synthesized CCLF, CCIL and CCOPF were tested as catalyst in the esterification of levulinic acid. Carbon cryogels showed high potential as an acid catalyst for levulinic acid esterification with above 70.0 mol.% yield of ethyl levulinate. The kinetic studies using CCLF and CCIL revealed the esterification of levulinic acid followed pseudo-first order kinetics and have low activation energy. Meanwhile, the thermodynamic parameters conferred the reaction was endergonic and more ordered

Preparation and characterization of impregnated magnetic particles on oil palm frond activated carbon for metal ions removal

The magnetic adsorbents i.e. oil palm frond-magnetic particles (OPF-MP) and oil palm frond activated carbon-magnetic particles (OPFAC-MP) have been prepared by impregnation of iron oxide via co-precipitation method. The magnetic adsorbents and their parent materials were characterized using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), Brunauer Emmett Teller (BET), Barrett, Joyner & Halenda (BJH) and t-plot method, x-ray diffraction (XRD) and also using vibrating sample magnetometry (VSM) to study their properties and surface chemistry. The activated carbon magnetic adsorbent confers high surface area of 700 m2/g with amorphous structure and magnetic properties of 2.76 emu/g. The OPF-MP and OPFAC-MP were then applied in adsorption study for ions removal of Pb(II), Zn(II) and Cu(II). OPFAC-MP has shown high removal efficiency of 100 % with adsorption capacity up to 15 mg/g of Pb(II), Zn(II) and Cu(II) ions compared to OPF-MP. In addition, the magnetic adsorbents were also compared with their parent materials to observe the effect of magnetic particles. Accordingly, the impregnation of magnetic particles enhances the metal ions adsorption comparing to their parent materials

Impregnation of magnetic particles on oil palm shell activated carbon for removal of heavy metal ions from aqueous solution

Oil palm shell activated carbon magnetic particle (CAC-MP) was prepared for adsorption of metal ions (Zn2+, Pb2+, Cu2+). Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), surface area and pore analysis (BET, BJH and t-plot method), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), and X-ray diffraction (XRD) were used to characterize CAC-MP. Its properties were compared with the parent activated carbon (CAC). The CACMP, with a high surface area (1007 m2/g), was used to study metal ions removal at different pH, adsorbent dosage, and contact time. The removal efficiency of metal ion increased with increasing pH, dosage, and time until equilibrium was reached. The optimum condition for maximum removal efficiency was at pH 6 and absorbent dosage of 0.5 g. Kineti

One-pot liquefaction of cellulose to ethyl levulinate via 1-sulfonic acid-3-methyl imidazolium trichlorozincate as Brønsted-Lewis catalyst

The direct conversions of cellulose to ethyl levulinate (EL) via Brønsted acidic ionic liquid (BAIL), Lewis acidic ionic liquid (LAIL), and Brønsted-Lewis acidic ionic liquid (BLAIL) conducted in this study is a sustainable approach. Initially, BAIL 1-sulfonic acid-3-methyl imidazolium chloride [SMIM][Cl] was prepared by the mixing of 1-methylimidazole, dry dichloromethane, and chlorosulfonic acid. Then, Lewis acidic site was provided to the BAIL by the addition of zinc chloride (ZnCl2), to synthetize BLAIL 1-sulfonic acid-3-methyl imidazolium trichlorozincate, [SMIM][ZnCl3]. Meanwhile, LAIL 1-butyl-3-methyl imidazolium trichlorozincate [BMIM][ZnCl3] was prepared by the addition of ZnCl2 to a neutral 1-butyl-3-methyl imidazolium chloride [BMIM][Cl]. These three catalysts were then characterized and employed in the one-pot liquefaction process that was conducted in a stainless-steel batch reactor at 180 °C for 10 hr, by charging 0.6 g of cellulose, 40 mL of ethanol and 3 g of catalyst. A parameter study, mainly temperature (120-200) °C, time (2-10) hr, and cellulose loading (0.2-1.0) g, were then conducted to determine the selected parameters to obtain high EL yield. Among the employed ionic liquids (ILs), BLAIL [SMIM][ZnCl3] exhibited the highest catalytic activity, which was contributed mainly by its co-existence of Brønsted and Lewis acidic sites as detected in Fourier-Transform Infrared (FTIR) analysis, and its high acidic value. The maximum EL yield (20.27 wt%) was obtained under conditions of 180 °C, 6 hr, 0.6 of cellulose, and 3 g of [SMIM][ZnCl3]. The outcome of this study provides an insight on the potential of novel [SMIM][ZnCl3] in facilitating the direct cellulose ethanolysis to EL

Synthesis and characterization of porous microspherical ionic liquid carbon cryogel catalyst for ethyl levulinate production

A new type of carbon cryogel was synthesized from ionic liquid, a green solvent, and furfural mixtures. Initially, the gel, formed via sol-gel polycondensation reaction, was freeze-dried, calcined and denoted as CCIL. The effect of furfural to IL (F/IL) ratio, water to IL (W/IL) ratio and sulfuric acid loading on the synthesis of gel was investigated. In addition, the effect of calcination temperature and time were also studied for CCIL preparation. The physical and chemical properties were evaluated with nitrogen physisorption, temperature programmed desorption of ammonia (NH 3 -TPD), and thermogravimetric analyzer (TGA). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive X-ray spectrometry (FESEM-EDX), CHNS analysis, total organic carbon (TOC) and nuclear magnetic resonance spectroscopy (NMR) results were also analyzed. Catalytic testing, conducted to evaluate the performance of CCIL in esterification of levulinic acid with ethanol, inferred large total surface area and high acidity corroborated with good activity. The selected CCIL registered ethyl levulinate yield of 66.9 mol%. The experimental results demonstrated the catalyst, derived from new feedstocks, is a potential solid acid catalyst for biomass conversion

Synthesis and characterization of carbon cryogel microspheres from lignin-furfural mixtures for biodiesel production

The aim of this work was to study the potential of biofuel and biomass processing industry side-products as acid catalyst. The synthesis of carbon cryogel from lignin–furfural mixture, prepared via sol–gel polycondensation at 90 °C for 0.5 h, has been investigated for biodiesel production. The effect of lignin to furfural (L/F) ratios, lignin to water (L/W) ratios and acid concentration on carbon cryogel synthesis was studied. The carbon cryogels were characterized and tested for oleic acid conversion. The thermally stable amorphous spherical carbon cryogel has a large total surface area with high acidity. Experimental results revealed the optimum FAME yield and oleic acid conversion of 91.3 wt.% and 98.1 wt.%, respectively were attained at 65 °C for 5 h with 5 wt.% catalyst loading and 20:1 methanol to oleic acid molar ratio. Therefore, carbon cryogel is highly potential for heterogeneous esterification of free fatty acid to biodiesel

Synthesis and characterization of carboxymethyl cellulose derived from empty fruit bunch

Oil palm empty fruit bunch (EFB), a cellulose rich lignocellulosic biomass has huge potential to be utilised as a raw material for the synthesis of carboxymethyl cellulose (CMC). In this study, CMC was synthesised from EFB extracted cellulose at the optimum carboxymethylation reaction conditions. The extracted cellulose yield obtained by alkaline treatment followed by bleaching with hydrogen peroxide was 45.5 wt.%. The cellulose structure was elucidated using thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) patterns. Meanwhile, the synthesised CMC was characterised with FT-IR, XRD and scanning electron microscopy (SEM). The maximum degree of substitution (DS) obtained was 1.30 with the yield of 177.51 wt.% and purity 89% determined using chemical methods at the optimum conditions of 30 wt.% of NaOH, 18 g of SMCA, 65 °C, 3 h reaction time and less than 75 μm of EFB-cellulose particle size. XRD analysis inferred low crystallinity while FTIR spectra verified the CMC structure and presence of different functional groups. The results for DS and EFB CMC yield obtained from this work were considerably higher than those reported in the literature. The synthesised EFB CMC can be further utilised in various industries such as detergent, mining, flotation, and oil and gas drilling muds applications

Kinetics and thermodynamic analysis of levulinic acid esterification using lignin-furfural carbon cryogel catalyst

The synthesis of ethyl levulinate, a fuel additive, by catalytic esterification of levulinic acid with ethanol over carbon cryogel has been investigated. The carbon cryogel catalyst, coupled with a large surface area and strong acidity, has been identified as an effective carbon-based catalyst for obtaining high ethyl levulinate yield of 86.5 mol%. The pseudo-homogeneous kinetic model is adopted to evaluate the different reaction orders. The first-order pseudo-homogeneous model is considered most suitable (R2 > 0.98) while the selection of kinetic model is also clarified and supported by the linearity of the parity plot. The activation energy of the esterification reaction is estimated to be 20.2 kJ/mol. Based on the thermodynamic activation parameters, the reaction is classified as endergonic and more ordered. The results from this study could provide valuable information for reactor modeling and simulation purposes in the future

Synthesis and characterization of carboxymethyl cellulose derived from empty fruit bunch

Oil palm empty fruit bunch (EFB), a cellulose rich lignocellulosic biomass has huge potential to be utilised as a raw material for the synthesis of carboxymethyl cellulose (CMC). In this study, CMC was synthesised from EFB extracted cellulose at the optimum carboxymethylation reaction conditions. The extracted cellulose yield obtained by alkaline treatment followed by bleaching with hydrogen peroxide was 45.5 wt.%. The cellulose structure was elucidated using thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) patterns. Meanwhile, the synthesised CMC was characterised with FT-IR, XRD and scanning electron microscopy (SEM). The maximum degree of substitution (DS) obtained was 1.30 with the yield of 177.51 wt.% and purity 89% determined using chemical methods at the optimum conditions of 30 wt.% of NaOH, 18 g of SMCA, 65 °C, 3 h reaction time and less than 75 µm of EFB-cellulose particle size. XRD analysis inferred low crystallinity while FTIR spectra verified the CMC structure and presence of different functional groups. The results for DS and EFB CMC yield obtained from this work were considerably higher than those reported in the literature. The synthesised EFB CMC can be further utilised in various industries such as detergent, mining, flotation, and oil and gas drilling muds applications

Glucose-derived bio-fuel additive via ethanolysis catalyzed by zinc modified sulfonated carbon

The transformation of biomass derivative components such as glucose to levulinate esters via direct conversion in alcohol with acid catalyst has attracted great attention. In this study, the sulfonate urea-furfural carbon cryogel doped with zinc (UFCS-Zn) has been applied as an acid catalyst for the glucose ethanolysis reaction. Initially, the carbon cryogel was prepared via a mixing process of urea and furfural in an acidic medium followed by freeze-drying and calcination steps. Then, the urea-furfural carbon cryogel (UFC) was sulfonated before modification with zinc via impregnation of zinc (II) nitrate to provide the Bronsted and Lewis acid catalyst which is required for reaction conversion. The effects of reaction parameters on the ethanolysis of glucose have been conducted to determine the selected condition in obtaining high ethyl levulinate yield. The parameters studied include the glucose feed (0.2 to 0.5 g), catalyst loading (0.15 to 1.2 g), and reaction temperature (140 to 190 °C). The catalyst was characterized using TGA-DTG, FTIR, and SEM-EDX techniques to study the surface chemistry and thermal stability. The glucose ethanolysis reaction with UFCS-Zn catalyst has provided maximum ethyl levulinate yield of 27.4 mol% at selected condition of 180 °C, 6 h, 0.8 g (1:2) of catalyst and 0.4 g of glucose. Based on characterization of UFCS-Zn, the presence of sulfonate group and Zn element on the catalyst through the sulfonation and impregnation steps have been verified. This result has been confirmed through the detection of SO3H functional group and Zn-O bonding from the FTIR, and elements of S, O, and Zn from the EDX. High thermal stability of the UFCS-Zn (via TGA-DTG curves) allows the catalyst to assist the reaction at setting temperature without degradation in mass during the reaction. The UFCS-Zn catalyst has drafted its potential as catalyst for further conversion of biomass components