Samarium Promoted Ni/Al2O3 Catalysts for Syngas Production from Glycerol Pyrolysis

The current paper reports on the kinetics of glycerol reforming over the alumina-supported Ni catalyst that was promoted with rare earth elements. The catalysts were synthesized via wet impregnation method with formulations of 3 wt% Sm-20 wt% Ni/77 wt% Al2O3. The characterizations of all the as-synthesized catalysts were carried out, viz.  BET specific surface area measurements, thermogravimetri analysis for temperature-programmed calcination studies, FESEM for surface imaging, XRD to obtain diffraction patterns, XRF for elemental analysis, etc.. Reaction studies were performed in a stainless steel fixed bed reactor with reaction temperatures set at 973, 1023 and 1073 K employing weight hourly space velocity (WHSV) of 4.5×104 mL g-1 h-1. Agilent GC with TCD capillary column was used to analyze gas compositions. Results gathered showed that the BET specific surface area was 2.09 m2.g-1 for the unpromoted Ni catalyst while for the promoted catalysts, was 2.68 m2.g-1. Significantly, the BET results were supported by the FESEM images which showed promoted catalysts exhibit smaller particle size compared to the unpromoted catalyst. It can be deduced that the promoter can increase metal dispersion on alumina support, hence decreasing the size of particles. The TGA analysis consistently showed four peaks which represent water removal at temperature 373-463 K, followed by decomposition of nickel nitrate to produce nickel oxide. From reaction results for Sm promotion showed glycerol conversion, XG of 27% which was 7% higher than unpromoted catalyst. The syngas productions were produced from glycerol decomposition and created H2:CO product ratio which always lower than 2.0. The H2:CO product ratio of 3 wt% Sm promoted Ni/Al2O3 catalyst was 1.70 at reaction temperature of 973 K and glycerol partial pressure of 18 kPa and suitable enough for Fischer-Tropsch synthesis. 

Optimisation of Bioethanol Production from Oil Palm Trunk Sap

This paper presents an optimization of bioethanol production from oil palm trunk sap (OPTS) fermentation. The OPTS was obtained from an old palm tree (30 years old), whereas ethanol fermentation was carried out using Saccharomyces cerevisiae. The sugar content in OPTS and fermentation mother liquor was determined using high-performance liquid chromatography (HPLC). The parameters such as initial pH, temperature, and agitation rate were optimised using response surface methodology (RSM) with rotatable central composite design (CCD). It was found that the highest yield of bioethanol (75.82%) was obtained at the initial pH (5.79), temperature (31.05 ºC), and agitation rate (164.38 rpm). The optimization model of OPTS fermentation to bioethanol developed in this work may provide useful guidance to obtain a high ethanol yield from OPTS

Removal of heavy metals from industrial wastewater using activated carbon

The presence of heavy metals in wastewater is known to cause severe damage to aquatic life, beside the fact that these metals kill microorganism during biological treatment of wastewater with a consequent time delay of the treatment process. Chromium is one of the major heavy metals present in wastewater which has toxic effect and is a strong oxidizing agent capable of being absorbed through the skin. Palm oil mills in Malaysia produce about 4.3 million tones of shell and the significant problems in the palm fruit processing is managing the wastes generated during the process. The palm shell can be converted into useful products such as activated carbon. So, this method will reduce industrial wastewater problem and will bring benefits to society. Hence, this research aims to use activated carbon produced from palm shell to remove Chromium from industrial wastewater. Pyrolysis was applied for the preparation of activated carbon from palm shell using furnace at 600ºC. The treatment of activated carbon was carried out by oxidizing it with sulphuric acid and coating with chitosan. Two adsorbents namely Palm Shell Activated Carbon (PSAC) and Palm Shell Activated Carbon coated with Chitosan (PSACC) were used to remove chromium from aqueous solution. The effects of pH of the solution, adsorbent dosage, agitation speed, and contact time on adsorption of chromium were studied. The experimental results proved that the chromium removal efficiency of PSACC was better compared PSAC. Freundlich and Langmuir isotherms were used to analyze the adsorption of chromium from aqueous solution. The results concluded that Freundlich isotherm captured the adsorption of Chromium better compared to Langmuir isotherm as the former have higher correlation regression coefficient

Synthesis, Characterization and Catalytic Performance of Ceria-Supported Cobalt Catalyst for Methane Dry Reforming To Syngas

In this study the synthesis, characterization and catalytic performance of CeO2 (Ceria) supported Co catalyst was investigated. First, the ceria was synthesized by direct thermal decomposition of Ce(NO3)3.6H2O and subsequently impregnated with 20 wt.% Co using aqueous solution of Co(NO3)2.6H2O as a precursor. The synthesized catalyst was characterized using TGA, N2-adsorption-desorption, X-ray Diffractometry (XRD), Field Emission Scanning Electron Microscope (FESEM-EDX), and Fourier Transformation Infrared (FTIR). The catalytic property of the ceria-supported cobalt catalyst was tested in methane dry reforming using a stainless steel fixed bed reactor. The dry reforming reaction was performed at the temperature range of 923-1023 K under a controlled atmospheric pressure and constant gas hourly space velocity (GHSV) of 30000 h-1. The effects of reactant (CH4 and CO2) feed ratio was investigated on reactants conversion, product yields, and selectivity. The ceria-supported cobalt catalyst recorded highest catalytic activity at a CH4: CO2 ratio of 0.9 and temperature of 1023 K. The highest values of 79.5% and 87.6% were recorded for the CH4 and CO2 conversions respectively. Furthermore, highest yields of 41.98% and 39.76%, as well as selectivity of 19.56% and 20.72%, were obtained for H2 and CO respectively. Syngas ratio of 0.90 was obtained from the dry reforming of methane, making it suitable as feedstock for Fischer-Tropsch synthesis (FTS)

A Study on the Kinetics of Syngas Production from Glycerol over Alumina-Supported Samarium-Nickel Catalyst

The current paper reports on the kinetics of syngas production from glycerol pyrolysis over the alumina-supported nickel catalyst that was promoted with samarium, a rare earth element. The catalysts were synthesized via wet-impregnation method and its physicochemical properties were subsequently characterized. Reaction studies were performed in a 10 mm-ID stainless steel fixed bed reactor with reaction temperatures maintained at 973, 1023 and 1073 K, respectively, employing weight-hourly-space-velocity of 4.5�104 ml g-�1 h-�1. The textural property examination showed that BET specific surface area was 2.09 m2 g-�1 for the unpromoted catalyst while the samarium promoted catalyst has 2.68 m2 g-�1. Interestingly, the results were supported by the FESEM images which showed that the promoted catalyst has smaller particle size compared to the unpromoted catalyst. Furthermore, the NH3- and CO2-TPD analyses proved that the strong and weak acid-basic sites were present. During glycerol pyrolysis, the syngas was produced directly from the glycerol decomposition. This has created H2:CO ratios that were always lower than 2.0, which is suitable for Fischer-Tropsch synthesis. The activation energy based on power law modeling for the unpromoted catalyst was 35.8 kJ mol-�1 and 23.4 kJ mol-�1 for Sm-promoted catalyst with reaction order 1.20 and 1.10, respectively. Experimental data were also fitted to the LangmuireHinshelwood model. Upon subjected to both statistical and thermodynamics consistency criteria, it can be conclusively proved that single-site mechanisms with associative adsorption of glycerol best describe the glycerol pyrolysis over both unpromoted and Sm promoted catalyst in the current work, with regression coefficient values of more than 0.9

Catalytic Pyrolysis of Glycerol Into Syngas Over Ceria-promoted Ni/α-Al2O3 Catalyst

This paper reports on the catalytic pyrolysis of glycerol into syngas over a 3 wt%Ce-20 wt%Ni/77 wt% α-Al2O3 catalyst and at reaction temperatures of 973 K, 1023 K and 1073 K. NH3- and CO2-TPD analyses have revealed that the as-synthesized catalyst was net acidic with acid-to-basic site ratio of 1.24. This provides ideal conditions for chemisorption of glycerol. In addition, the BET specific surface area was 2.89 m2 g−1. The small surface area can be attributed to the thermally stable α-Al2O3 support. In addition, the average crystallite size was 40.22 nm. The catalytic glycerol pyrolysis produced gaseous products that were comprised of H2, CO, CO2 and CH4 only with H2:CO ratios that were consistently less than 2.0. This ratio is suitable for Fischer-Tropsch synthesis. The yields of CO2 and CH4 were several folds lower than the yields of H2 and CO, indicating that the latter were from primary reaction, viz. glycerol decomposition whilst the former were from secondary competing reactions. In addition, the activation energy obtained via Langmuir-Hinshelwood model was 25.34 kJ mol−1. Used catalyst characterization showed that the carbonaceous deposit was in the forms of whisker-type. This type of carbon deposit would not physically deactivate the catalyst

Renewable Syngas Production from Thermal Cracking of Glycerol over Praseodymium-Promoted Ni/Al2O3 Catalyst

In this study, the kinetics of glycerol pyrolysis over a 3wt%Pr-20wt%Ni/77wt%α-Al2O3 catalyst was investigated. The catalyst was synthesized via wet-impregnation method and was characterized using temperature-programmed calcination (TPC), temperature-programmed reduction (TPR), N2-physisorption, FESEM imaging, X-ray diffraction and CO2-/NH3-temperature-programmed desorption (TPD). The catalytic activity of the as-synthesized 3wt% Pr-Ni/α-Al2O3 catalyst was evaluated in a stainless steel fixed bed reactor at temperatures that ranged from 973 K to 1073 K and a weight-hourly-space-velocity (WHSV) of 4.5×104 ml g-1 h-1 under the atmospheric condition. The main gaseous products from catalytic glycerol pyrolysis were H2, CO, CO2 and CH4 (descending ranking) with the highest H2 formation rate and H2 yield of 0.02593 mol g cat−1 s−1 and 29.04%, respectively. The analysis of the kinetic data obtained from the glycerol pyrolysis showed activation energy of 37.36 kJ mol-1. Based on the mechanistic modeling, it can be deduced that the rate determining step of the glycerol pyrolysis was via a single site associative adsorption with molecular surface reaction as the rate-determining step

Influence of Nutrient Addition on the Bioethanol Yield from Oil Palm Trunk Sap Fermented by Saccharomyces Cerevisiae

This paper presents the influence of nutrient addition namely MgSO4, C3H7NO2, (NH4)2SO4 and Na2HPO4 to the bioethanol yield from oil palm trunk saps (OPTS) with fermentation carried out by Saccharomyces cerevisiae. The sugar and ethanol contents in the sample were determined using a high-performance liquid chromatography. Nutrient addition has improved the bioethanol yield markedly, with the average yield ranged from 58.50% to 77.12% compared to about 51.08% without nutrient addition. The highest bioethanol yield (81.89%) was achieved by adding MgSO4. The rank of nutrient influence on improving the bioethanol yield was MgSO4 > C3H7NO2 > (NH4)2SO4 > Na2HPO

Synthesis and characterization of a La Ni/α-Al2O3catalyst and its use in pyrolysis of glycerol to syngas

The current paper reports on the kinetics of syngas production from glycerolcatalytic pyrolysis over Ni/α-Al2O3 catalyst promoted by lanthanum. The 3 wt%La-20 wt%Ni/77 wt%α-Al2O3 catalyst was synthesized and its physiochemical properties were characterized. The BET specific surface area was 2.20 m2.g−1, which was 0.11 m2.g−1 larger than the unpromoted Ni/α-Al2O3 catalyst. Significantly, the BET results were supported by the FESEM image which showed that the promoted catalyst has smaller particle size compared to the unpromoted catalyst. The NH3 and CO2-TPD analyses indicates that the catalyst has net acidity with acid:base ratio of 1.12. Catalytic pyrolysis was performed in a 10 mm-ID stainless steel fixed bed reactor with reaction temperatures set at 973, 1023 and 1073 K, employing a weight-hourly-space-velocity (WHSV) of 4.5 × 104 ml g−1 h−1. From reaction studies, the highest glycerol conversion (XG) value was 36.96% at 1073 K. The resulting syngas has H2:CO ratios always lower than 2.0. Subsequently, mechanistic studies indicate that the catalytic glycerol pyrolysis occurred on single catalytic site via associative adsorption, with molecular surface reaction as the rate-determining step

Synthesis, Characterization and Catalytic Performance of Samarium Sesquioxide supported Cobalt Catalyst for Methane Dry Reforming to Syngas

This study focuses on the synthesis, characterization and performance of 20wt%Co/80wt%Sm2O3 catalyst in methane dry reforming for the production of syngas. The20wt%Co/80wt%Sm2O3 catalyst was synthesized via wetimpregnation method and characterized by TGA, FTIR, XRD, FESEM, EDX, N2 physisorption and H2-TPR. The performance of the catalyst in the methane dry reforming reaction was studied in a stainless steel fixed-bed continuous flow reactor at feed (CH4:CO2) ratio of 1.0, temperature ranged 923-1023K and GHSV of 30000 h-1. The 20wt%Co/80wt%Sm2O3 catalyst showed promising catalytic performance evident from the highest CH4 and CO2 conversion of ~71% and ~72% as well as the highest H2 and CO yield of ~62% and ~73%, respectively. Moreover, the methane dry reforming over the 20wt%Co/80wt%Sm2O3 catalyst produces H2: CO ratio close to unity, hence suitable for use as a chemical intermediate for synthesis of oxygenated fuels. The characterization of the used 20wt%Co/80wt%Sm2O3 catalyst used after 4 h of time-onstream confirmed the presence of amorphous carbon which can easily be gasified