Catalyst Weight Ratio Research Articles

Molybdenum disulfide decorated palm oil waste activated carbon as an efficient catalyst for hydrogen generation by sodium borohydride hydrolysis

Development of cost-effective catalyst material with enhanced activity for hydrogen generation is highly desirable for hydrogen powered portable applications. In this work, molybdenum disulfide (MoS2) incorporated on palm oil waste activated carbon (POAC) was used as a novel catalyst for enhanced hydrogen production by sodium borohydride (NaBH4) hydrolysis. Hydrothermally synthesized MoS2/POAC catalyst composite was characterized by SEM, EDX, XRD, FTIR, Raman, TGA and Surface area analysis. Characterization studies revealed the uniform and complete synthesis of MoS2 nanoparticles on the POAC surface with crystallite size of 18.2 nm. The catalyst composite showed enhancement in thermal stability and reduction in specific surface area as compared with POAC. Hydrogen generation investigations showed ideal weight ratio of composite catalyst as 10:1 (w/w of POAC: MoS2) and optimal catalyst to feed weight ratio as 0.07. MoS2/POAC catalyst with 10 wt% of POAC loading recorded the maximum catalytic activity of 1170.66 mL/g min with lower activation energy of 39.1 kJ/mol. The catalyst composite exhibited virtuous reusability with a 28% loss in activity for nine cycle regeneration run. Thus, MoS2/POAC catalyst system is highly attractive for commercial applicability and is a potential candidate for enhanced hydrogen production through NaBH4 hydrolysis.

Effective catalysts derived from waste ostrich eggshells for glycolysis of post-consumer PET bottles

Herein, we report an effective chemical recycling of poly(ethylene terephthalate) (PET) using sustainable sources of catalysts, calcium oxide (CaO) derived from ostrich eggshells. The active catalysts were demonstrated in the chemical depolymerization of post-consumer PET bottles. Beverage bottles were proceeded with 1 wt% catalyst derived from ostrich eggshells in the presence of ethylene glycol at 192 °C under atmospheric pressure to give the major product as bis(2-hydroxyethyl terephthalate) (BHET) which was confirmed by melting point, IR spectroscopy, 1H-, 13C-NMR spectroscopy and mass spectrum. The catalyst could fully depolymerize PET within 2 h, producing a good yield of highly pure BHET monomer. The catalysts were successfully characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy with energy dispersive X-ray spectroscopy analysis (FE-SEM), and thermo-gravimetric analysis (TGA). Furthermore, catalysts derived from chicken eggshells, geloina, mussel, and oyster shells were run to compare the catalytic activities. For better understanding of catalytic parameters, effects of calcination temperatures of catalyst, weight ratio of catalyst, ratio of weight of solvent, and time of depolymerization for the ostrich eggshells catalyst were also investigated.

Production of biodiesel by electrolysis method from waste cooking oil using heterogeneous MgO-NaOH nano catalyst

ABSTRACTBiodiesel production was made by the electrolysis of the waste cooking oil by using heterogeneous nano catalysts. Seven types of catalysts (MgO-KOH, MgO-NaOH, CaO-KOH, CaO-NaOH, and combination of them) were prepared and the effects of different catalyst amount were investigated. The results showed that using MgO-NaOH nano catalyst weight ratios to oil (3 and 5) produced biodiesel with 94–98% yield. The prepared biodiesel was in accordance with the world standard of fuel ASTM and EN. Scanning electron microscopy images and X-Ray diffraction patterns of the prepared nano catalyst showed that the average mean crystal size of the particles was 66.77 nm.

The Effects of Catalyst Weight and Mole Ratio of Oil-Methanol on Crude Palm Oil (CPO) Esterification using H2SO4 (3M) / Clay Catalyst

This study aimed to synthesize biodiesel from CPO using heterogeneous clay catalyst activated with H2SO4 (3M) in the esterification step. The catalyst was synthesized by the method of reflux at a temperature of 85 °C. The catalyst was characterized using XRD and XRF. The synthesized catalyst was used to make biodiesel from CPO by esterification process with the variations of catalyst weight and the mole ratio of oil to methanol. The purity of biodiesel was analyzed using GC. The XRD results showed that sulfuric acid activated clay consisted of sharp intensities of silica and this was supported by XRF results in which the silica content was 87.05% while Al2O3 was 11.90%. Heterogeneous acid catalyst of H2SO4 / clay with 3M H2SO4 concentration could reduce a free fatty acid content of the oil as much as 85.2%, ie from 6.61% to 0.98%. The maximum Biodiesel yield after the process of transesterification using CaO catalyst from shells of blood cockle (anadara granosa) was 71.90%. The maximum Biodiesel yield was obtained at the optimum esterification reaction conditions that were the weight of the catalyst of 2%, the mole ratio (oil: methanol) 1:18 with a reaction temperature of 65 ± 2 °C for 3 hours.

Fabrication of Graphitic Carbon Spheres via a Hydrothermal Carbonization Combined Catalytic Graphitization Method Using Cobalt as Catalysts

Graphitic carbon spheres (GCS) with an average diameter of 1.6 μm were prepared via a hydrothermal carbonization combined catalytic graphitization method using glucose as carbon source and cobalt nitrate as catalyst precursor. The as-prepared GCS were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. It was found that the optimal weight ratio of Co catalyst for graphitization of amorphous carbonaceous spheres was 2.0 wt%, and the optimal temperature and dwelling time required for graphitization were respectively 1100 °C and 3 h.

High density Polyethylene plastic waste treatment with microwave heating pyrolysis method using coconut-shell activated carbon to produce alternative fuels

Pyrolysis is a technology that could crack polimer such as plastic waste into alternative fuels. This research uses microwave heating methode, which more efficient than conventional heating methode. The plastic waste used is 200 grams of HDPE, with feed to catalyst weight ratio are 1:1, 0.6:1, 0.4:1. Pyrolysis was run at temperatures of 250, 300, 350, & 400 °C for 15, 30 and 45 min. From the experimental result, the best variable of pyrolysis process with microwave method is at 45 minutes, at 400°C, and 1:1 feed to catalyst weight ratio. Result shows that yield of liquid and gas product is 99.22%; yield of residue is 0.78%; value of liquid product’s composition (cycloparaffin and n-paraffin) is 54.09% and concentration of methane gas is 10.2%.

Lewis acidity induced heteropoly tungustate catalysts for the synthesis of 5-ethoxymethyl furfural from fructose and 5-hydroxymethylfurfural

Heteropoly tungstate with tantalum ions in its secondary structure were prepared and subsequently dispersed on tin oxide. The prepared materials physical and chemical properties were estimated by different spectroscopic methods Characterization results indicate that the stable Keggin ion of tantalum heteropoly tungstate was well preserved on support. New Lewis acidic sites were generated with the presence of Ta ions in heteropoly tungstate. These samples were tested for their catalytic performance towards conversion of fructose to 5-ethoxy methyl furfural (EMF) and selective etherification of 5-hydroxymethylfurfural (HMF) with ethanol. The catalyst with 30 wt% of active component on SnO2 exhibited highest HMF etherification activity with 90% of 5-ethoxymethylfurfural yield with in 45 min. The catalysts also able to converted fructose into EMF in one-pot with a yield of 68%. The etherification activity over these catalysts was studied under the influence of different reaction parameters such as reaction temperature, reaction time, catalyst weight and reactants mole ratio.

Direct conversion of glucose to 5-hydroxymethylfurfural using a mixture of niobic acid and niobium phosphate as a solid acid catalyst

The aim of this work was to optimize the acid-catalyzed conversion of glucose into 5-hydroxymethylfurfural (HMF) in an aqueous medium using niobic acid (NbO), niobium phosphate (NbP) and a mixture of both solid acid catalysts. A simplex-centroid mixture design was applied to optimize the mixture ratio between NbO and NbP. A central composite design was applied to process optimization. The studied variables were temperature (T), time (t) and substrate to catalyst weight ratio (RS/C). The mixture design revealed excellent glucose conversion (55%) and HMF selectivity (56%) when the weight ratio between NbO and NbP was equal to 1:1. The experimental results demonstrate that a mixture of both solid acids provides a better combination of Brønsted and Lewis acidity for effective glucose dehydration into HMF than each individual catalyst.

Effect of La2O3 replacement on γ-Al2O3 supported nickel catalysts for acetic acid steam reforming

The effect of replacement of γ-Al2O3 by La2O3 was studied on Ni catalysts for hydrogen production via acetic acid steam reforming. The La/(La + Al) weight ratio ranged from 0 to 1 in the catalyst support prepared by co-precipitation method. Over the Ni/La-3Al catalyst (the La/(La + Al) weight ratio at 0.25), the carbon conversion and hydrogen yield reached 100% and 72.72%, respectively, which was obviously higher than other catalysts at 700 °C, S/C = 1 and LHSV = 10 h−1. The effect of S/C, LHSV and stability test were studied in detail over Ni/La-3Al catalyst, whose high activity maintained for more than 30 h.

Direct synthesis of iso-butane from synthesis gas or CO2 over CuZnZrAl/Pd-β hybrid catalyst

The effect of various factors on the catalytic performance of iso-butane formation over CuZnZrAl/Pd-β hybrid catalyst via synthesis gas or CO2 hydrogenation has been deeply investigated in this work. It was interesting to note that the iso-butane/n-butane ratio value was much higher than that of thermodynamic equilibrium (about 1/1), whose value was directly related to the reaction condition using this hybrid catalyst. In order to further clearly clarify this finding, various experimental reaction factors were selected to investigate the formation of iso-butane. The results revealed that increasing temperature, H2/COx, CO2/COx, and/or Pd loading possessed an inhibiting effect on the iso-butane yield. High selectivity of iso-butane could be achieved by increasing the reaction pressure, W/F and the weight ratio of CuZnZrAl methanol catalyst to Pd-β catalyst. It is also noted that the addition of water seriously suppressed the reaction activity, resulting in the low ratio of iso-butane/n-butane. A possible reaction route was elucidated based on the latest results. This might shed light on the development of a high efficient catalyst for iso-butane production from synthesis gas or CO2 hydrogenation.

Enhancement of enzymatic hydrolysis and lignin removal of bagasse using photocatalytic pretreatment

Pretreatment for reduction of biological resistance in a lignocellulosic material, i.e. bagasse, for enzymatic hydrolysis and fermentation was investigated. Photocatalyst (TiO2) was used as an additive composition to assist this pretreatment process. Reaction time was varied (24, 48, and 72 h) to find the optimum condition for the pretreatment, while concentration of solvent (NaOH, H2O2, or NH4OH), biomass to solvent ratio, and weight ratio of catalyst to bagasse were fixed at 2 M, 1:20 g/ml (typically, solvent = 150 ml), and 1:5, respectively. Batch reaction temperature was at 25°C. After the pretreatment, the enzymatic digestibility of pretreated bagasse was carried out to find the sugar yield. Hydrolysis of pretreated bagasse with photocatalyst show higher sugar yields than the conventional reactions without photocatalyst. The maximum yields of sugars (541.03 mg glucose and 192.79 mg pentose) were obtained at the longest reaction time.

Validation of the H2 production stage via SER under relevant conditions for the Ca/Cu reforming process practical application

The joint performance of a CaO-based sorbent and a Ni-based commercial catalyst has been assessed under relevant conditions for the SER stage in the Ca/Cu H2 production process. These conditions comprise processing CH4 space velocities suitable for the scaling up of the process, operation of the system at pressure, and testing materials that had experienced up to 200 oxidation/reduction cycles. The system, catalyst and CaO-based sorbent, was able to fulfil the SER equilibrium composition up to 2.5kgCH4h−1kgcat−1, CH4 space velocity that would allow the scaling up of the process. In this way, a gas stream containing up to 95% vol. H2 was obtained at 923K, steam to carbon ratios of 3.2 and 4, sorbent to catalyst weight ratios from 4 to 15 and for operation pressures between 1 and 9bar. The effect of oxidation/reduction cycles on catalyst performance was assessed, and the mixture sorbent and aged catalyst was able to process up to 2.5kgCH4h−1kgcat−1, corroborating the operational limit determined for the fresh materials.The total operation pressure (from 1 to 9bar) did not have an important influence on H2 yield, and/or materials performance. Sorbent carbonation reaction rates up to 4.42*10−2kmolh−1kgsorb−1 were determined in the experiments, being this parameter responsible of the limit in CH4 space velocity that can be successfully converted through this sorbent/catalyst system. The experimental results have been successfully described by a pseudo-homogeneous reactor model that incorporates the main kinetic expressions of the reactions involved in the SER stage.

Catalytic pyrolysis of coconut copra and rice husk for possible maximum production of bio-oil

The main objective of the present work is to study the effect of the nickel catalyst on pyrolysis of coconut copra and rice husk via thermo gravimetric analysis (TGA). The optimisation of catalyst weight ratio on biomass is also determined. The sample is pyrolysed from 30 °C up to 700 °C at 10 °C/min of heating rate in nitrogen (N2) environment flowing at 150 mL/min. The catalyst (Ni-Ce/Al2O3) was prepared via wet impregnation method, with alumina (Al2O3) as support, while cerium (Ce) and nickel (Ni) act as promoter. The samples were prepared accordingly with biomass to catalyst weight loading ratio and labelled as follows; rice husk as RH-2 (1 : 0.15) and RH-3 (1 : 0.50) including coconut copra as CC-2 (1 : 0.15) and CC-3 (1 : 0.50). For comparison, the pyrolysis of coconut copra and rice husk without catalyst also are conducted at the same operating condition and named as CC-1 (1 : 0) and RH-1 (1 : 0). The TGA-DTG curves show that, the presences of catalyst significantly affect the devolatilisation rate of biomass. The highest volatile matter was achieved by CC-2 at 83.27 % compared to RH-2 at only 46.66 %. Although at similar biomass to catalyst weight ratio of 1 : 0.15, the coconut copra is more favourable to yield a high volatile matter than the rice husk. At the same time, both biomass samples specifically CC-3 and RH-3 have achieved the highest in solid residual yield. Overall, the mass loss of volatile matter decreases in the order of CC-2 > CC-1 > CC-3 > RH-1 > RH-2 > RH-3. In summary, the optimum catalyst loading was at CC-2 and RH-2 that work best to degrade at the highest mass loss of volatile, in which attributes to higher yield of pyrolysis oil.

Enhanced photocatalytic activity of g-C3N4-TiO2 nanocomposites for degradation of Rhodamine B dye

Abstract g-C 3 N 4 -TiO 2 nanocomposites have been synthesized by simple chemical route with high photocatalytic activity under visible light irradiation. Different weight ratio of catalyst were used for the photodegradation of Rhodamine B dye. It was observed that the composite with 2:1 wt ratio of g-C 3 N 4 and TiO 2 respectively shows maximum photocatalytic activity with photocatalytic rate as ∼0.17 min −1 which is ∼10 times higher than pure TiO 2 . At an optimal concentration of g-C 3 N 4 , lifetime of the excited electrons was found to increase from 2.65 to 10.20 ns in the composite compared to TiO 2, suggesting efficient separation of electrons and holes. The favorable band position of g-C 3 N 4 and composite supports the increase in the charge separation rate of electron and hole during photocatalytic reaction. The role of active species involved in the degradation of the organic dye during photocatalysis by g-C 3 N 4 -TiO 2 has been investigated (like radical species).

Effect of CV-ZSM-5, Ni-ZSM-5 and FA-ZSM-5 catalysts for selective aromatic formation from pyrolytic vapors of rubber wastes

A large and increasing amount of polymeric wastes, including plastic, rubber and tyres, are produced each year causing increasing disposal and environmental problems. The recycling of these wastes is an alternative way to solve the problem of polymeric waste management. Thermal/catalytic degradation (pyrolysis) of these wastes is of interest for liquid fuel production. In this work, rubber waste collected from the bicycle brake industry was used as the feedstock for pyrolysis for liquid fuel production. Three HZSM-5 zeolites, synthesized from the conventional hydrothermal method (CV-HZSM-5), Ni loaded HZSM-5 (Ni-HZSM-5) and HZSM-5 derived from fly ash (FA-HZSM-5), were examined for their catalytic performance in the fast pyrolysis of rubber waste using analytical gas chromatography-mass spectrometry. The pyrolysis was performed at 500°C with different rubber: catalyst weight ratios (1:1, 1:5 and 1:10). Increasing the catalyst content remarkably enhanced the formation of aromatic hydrocarbons and decreased the non-aromatic fractions drastically, and was optimal at a rubber: catalyst ratio of 1:5 yielding 80.8–95.9% aromatic and 2.8–18.7% aliphatic hydrocarbon products and only approximately 2% oxygenates and nitrogenates. The aromatic selectivity of the catalysts was ranked in the order of CV-HZSM5>Ni-HZSM-5>FA-HZSM5. Overall, the three HZSM-5 catalysts showed a superior catalytic performance for upgrading pyrolytic vapours from rubber wastes in terms of enhancing the aromatic production, especially benzene, toluene and xylene compounds.

Synthesis of carbon nanotubes via Fe-catalyzed pyrolysis of phenolic resin

Carbon nanotubes (CNTs) with 40–100nm in diameter and tens of micrometers in length were prepared via catalytic pyrolysis of phenol resin in Ar at 673–1273K using ferric nitrate as a catalyst precursor. Structure and morphology of pyrolyzed resin were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Ferric nitrate was transformed to Fe3O4 at 673K, and to metallic Fe and FexC carbide at 873–1273K. The optimal weight ratio of Fe catalyst to phenol resin for growing CNTs was 1.00wt%, and the optimal temperature was 1073K. In addition, use of a high pressure increased the yield of CNTs. Density functional theory (DFT) calculations suggest that Fe catalysts facilitate the CNTs growth by increasing the bond length and weakening the bond strength in C2H4 via donating electrons to the C atoms in it.

Synthesis of Carbon Nanotubes from Phenolic Resin Using Nickel Nitrate as a Catalyst Precursor

Carbon nanotubes (CNTs) with 20-40 nm in diameter and several micro-meters in length were prepared through catalytic pyrolysis of phenol resin at 400-1000 °C under Ar atmosphere using nickel nitrate as a catalyst precursor. Microstructure and morphology of pyrolysed resin were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the onset and optimal growth temperatures of CNTs were 400 and 800 °C respectively. Moreover, the optimal weight ratio of Ni catalyst to phenol resin was 0.75%.

Aeration Leaching of Iron from Nitrided Malaysian Ilmenite Reduced by Polystyrene-Coal Reductant

In this study, aeration leaching process of iron (Fe) from titanium oxycarbonitride (TiOxCyNz) produced by carbothermal reduction and nitridation of Malaysian ilmenite, in ammonium chloride (NH4Cl) solution was investigated. The reductant used for this study was a blend of Polystyrene (PS) and Mukah-Balingan coal from Sarawak and reduction temperature was 1200°C. Phase composition of reduced sample was analyzed using X-Ray Diffraction (XRD) and SEM/EDX. The leaching experiment was carried out for 4-6hours. The final solid sample was analyzed by XRD and SEM/EDX analysis while the filtered solution was analyzed by ICP-OES. Design of Experiment (DOE) analysis was used to find out the optimum condition for the leaching of metallic Fe in NH4Cl solution. In this study, a full factorial design model was used to detect the interaction between the three parameters. A fully randomized factorial design, with various combinations of PS/Coal (C) weight ratio, leaching time, and amount of catalyst added was investigated. It was observed that the leaching time was the most important factor affecting the amount of Ti and Fe extracted. The results of the design showed that the percentage of Fe extracted reached up to 76.85% at leaching time of 6hours, at PS/C ratio of 0.18 and using 1wt.% of glucose catalyst.

Kinetics and Mechanism of Ethyl Acetate Production Using Eco-Benign Solid Catalyst

The kinetics and mechanism of an eco-benign clay catalyst employed in the production of ethyl acetate was evaluated. The results obtained revealed that the conversion of acetic acid was dependent on the catalyst weight, reaction time and mole ratio. The maximum conversion of acetic acid was obtained for mole ratio (acid: alcohol) of 2:1 with optimum catalyst weight of 2.0g at a reaction temperature of 363K and 150 minutes time on-stream. Kinetic studies revealed that the esterification reaction was second-order and followed the single step Eley-Rideal reaction mechanism.

Green route to modification of wood waste, cellulose and hemicellulose using reactive extrusion

A large volume of wood waste is produced in timber processing industry which traditionally used in low value applications. Here, value addition to the wood waste (Sander dust) and cellulose, hemicellulose isolated thereof by functionalisation using cyclic anhydrides in a solvent-free and green reactive extrusion process is reported. The effect of extrusion temperature, catalyst and different weight ratios of Sander dust (SD):succinic anhydride (SA) on the esterification reaction is evaluated. The esterified products were characterised by the acid value, degree of substitution (DS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), solid state 13C NMR and thermo-gravimetric analysis (TGA). Under optimum extrusion conditions, mixed esters are formed, with highest acid value obtained for succinylation of cellulose (0.122g/g at DS of 0.350) which is two times higher compared to succinylated SD (0.059g/g at a weight gain of 0.452) and hemicellulose (0.043g/g at DS of 0.290). The reactivity trend for individual anhydride was: (1) SA−Cellulose>SD>hemicellulose; (2) maleic anhydride (MA)−SD>hemicellulose>cellulose and (3) dodecenyl succinic anhydride (DDSA)−SD≈cellulose≫hemicellulose. The pendant free carboxyl groups generated through functionalisation of wood waste, cellulose and hemicellulose without the presence of polymeric carriers will allow more tailored or targeted modification of wood-plastic composites.