Biodiesel production from jatropha oil by catalytic and non-catalytic approaches: an overview

Biodiesel (fatty acids alkyl esters) is a promising alternative fuel to replace petroleum-based diesel that is obtained from renewable sources such as vegetable oil, animal fat and waste cooking oil. Vegetable oils are more suitable source for biodiesel production compared to animal fats and waste cooking since they are renewable in nature. However, there is a concern that biodiesel production from vegetable oil would disturb the food market. Oil from Jatropha curcas is an acceptable choice for biodiesel production because it is non-edible and can be easily grown in a harsh environment. Moreover, alkyl esters of jatropha oil meet the standard of biodiesel in many countries. Thus, the present paper provides a review on the transesterification methods for biodiesel production using jatropha oil as feedstock

Pyrolytic–deoxygenation of triglyceride via natural waste shell derived Ca(OH)2 nanocatalyst

Cracking–Deoxygenation process is one of the important reaction pathways for the production of biofuel with desirable n-C17 hydrocarbon chain via removal of oxygen compounds. Calcium-based catalyst has attracted much attention in deoxygenation process due its relatively high capacity in removing oxygenated compounds in the form of CO2 and CO under decarboxylation and decarbonylation reaction, respectively. In the present study, deoxygenation of triolein was investigated using Ca(OH)2 nanocatalyst derived from low cost natural waste shells. The Ca(OH)2 nanocatalyst was prepared via integration techniques between surfactant treatment (anionic and non-ionic) and wet sonochemical effect. Results showed that sonochemically assisted surfactant treatment has successfully enhanced the physicochemical properties of Ca(OH)2 nanocatalyst in terms of nano-particle sizes (∼50 nm), high surface area (∼130 m2 g−1), large porosity (∼18.6 nm) and strong basic strength. The presence of superior properties from surfactant treated Ca(OH)2 nanocatalysts rendered high deoxygenation degree, which are capable of producing high alkane and alkene selectivity in chain length of n-C17 (high value of C17/(n-C17 + n-C18) ratio = 0.88). Furthermore, both Ca(OH)2–EG and Ca(OH)2–CTAB nanocatalysts showed high reactivity with 47.37% and 44.50%, respectively in total liquid hydrocarbon content of triolein conversion with high H/C and low O/C ratio

Process optimization design for jatropha-based biodiesel production using response surface methodology

Biodiesel of non food vegetal oil origin is gaining attention as a replacement for current fossil fuels as its non-food chain interfering manufacturing processes shall prevent food source competition which is expected to happen with current biodiesel production processes. As a result, non edible Jatropha curcas plant oil is claimed to be a highly potential feedstock for non-food origin biodiesel. CaO–MgO mixed oxide catalyst was employed in transesterification of non-edible J. curcas plant oil in biodiesel production. Response surface methodology (RSM) in conjunction with the central composite design (CCD) was employed to statistically evaluate and optimize the biodiesel production process. It was found that the production of biodiesel achieved an optimum level of 93.55% biodiesel yield at the following reaction conditions: 1) Methanol/oil molar ratio: 38.67, 2) Reaction time: 3.44 h, 3) Catalyst amount: 3.70 wt.%, and 4) Reaction temperature: 115.87 °C. In economic point of view, transesterification of J. curcas plant oil using CaO–MgO mixed oxide catalyst requires less energy which contributed to high production cost in biodiesel production. The incredibly high biodiesel yield of 93.55% was proved to be the synergetic effect of basicity between the active components of CaO–MgO shown in the physicochemical analysis

An Overview: Recent Development of Titanium Oxide Nanotubes as Photocatalyst for Dye Degradation

Today, organic dyes are one of the largest groups of pollutants release into environment especially from textile industry. It is highly toxic and hazardous to the living organism; thus, the removal of these dyes prior to discharge into the environment is essential. Varieties of techniques have been employed to degrade organic dyes and heterogeneous photocatalysis involving titanium dioxide (TiO2) appears to be the most promising technology. In recent years, TiO2 nanotubes have attracted much attention due to their high surface area and extraordinary characteristics. This paper presents a critical review of recent achievements in the modification of TiO2 nanotubes for dye degradation. The photocatalytic activity on dye degradation can be further enhanced by doping with cationic or anionic dopant

Electrochemical sensor based on single-walled carbon nanotube/ ZnO photocatalyst nanocomposite modified electrode for the determination of paracetamol

Electrodes modified with single-walled carbon nanotube/zinc oxide were prepared for electrochemical characterization and sensing of paracetamol. The modified electrodes were characterized using cyclic voltammetry, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The single-walled carbon nanotube/zinc oxide-modified glassy carbon electrode allowed an increased oxidative peak current of paracetamol with an enhancement factor of 4, in comparison to the bare electrode. Linear calibration plots of oxidative peak currents against paracetamol concentrations were obtained with a correlation coefficient as high as 0.994. The scan rate study suggested that the electrocatalytic processes were affected by both diffusion and adsorption processes. The effect of pH study indicated that the modified electrodes performed well under acidic conditions. The field emission scanning electron microscopy images showed the surface porosity of the composite with particle size increased after the electroanalysis. The energy dispersive X-ray analysis revealed the presence of carbon, zinc, and oxygen in the composite prior to electroanalysis, and additional phosphorus and potassium elements after electroanalysis. The analytic performance of this modified electrode was evaluated for the detection of paracetamol in commercial drugs with satisfactory results. Ultraviolet-visible spectrophotometry measurements were used to determine the band gap of single-walled carbon nanotube/zinc oxide nanocomposite. An unprecedented band gap of 3.11 eV was estimated. The proposed modified electrode exhibited better electrocatalytic activity in the determination of paracetamol. Potentially, the developed single-walled carbon nanotube/zinc oxide-modified glassy carbon electrode could be used for analytical applications

Synthesis of 2D boron nitride doped polyaniline hybrid nanocomposites for photocatalytic degradation of carcinogenic dyes from aqueous solution

This investigation focused on the photocatalytic treatment of pollutants in waste water using methylene blue (MB) and methyl orange (MO) as the model dyes. In this study, conducting polyaniline (PANI) based nanocomposites doped with 2D hexagonal boron nitride (h-BN) were synthesised using simplistic oxidative in-situ polymerization technique by employing ammonium persulfate as an initiator in acidic medium. The synthesised 2D h-BN doped PANI nanocomposites were comprehensively characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), elemental mapping, X-ray diffraction (XRD), Brunauer-Emmett-Teller analysis (BET), thermogravimetric analysis (TGA), and This investigation focused on the photocatalytic treatment of pollutants in waste water using methylene blue (MB) and methyl orange (MO) as the model dyes. In this study, conducting polyaniline (PANI) based nanocomposites doped with 2D hexagonal boron nitride (h-BN) were synthesised using simplistic oxidative in-situ polymerization technique by employing ammonium persulfate as an initiator in acidic medium. The synthesised 2D h-BN doped PANI nanocomposites were comprehensively characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), elemental mapping, X-ray diffraction (XRD), Brunauer-Emmett-Teller analysis (BET), thermogravimetric analysis (TGA), andform infrared spectroscopy (FTIR). Degradation of MB and MO dyes under UV irradiations was performed to evaluate the photocatalytic performance of the synthesised nanocomposites. The results indicated that the h-BN nanosheets doped nanocomposites demonstrated better photocatalytic activities as compared to bare PANI or h-BN. Moreover, the nanocomposite P-BN-2, with 2 wt% of 2D h-BN nanosheets was found to be an optimal composition with 93% and 95% degradation efficiency for MB and MO within 90 min respectively

Catalytic deoxygenation of triolein to green fuel over mesoporous TiO2 aided by in situ hydrogen production

The greenhouse gases contributed by combustion of fossil fuel has urged the need for sustainable green fuel production. Deoxygenation is the most reliable process to convert bio-oil into green fuel. In this study, the deoxygenation of triolein was investigated via mesoporous TiO2 calcined at different temperature in the absence of external H2. The high conversion of fuel-liked hydrocarbons showed the in situ H2 produced from the reaction. The mesoporous TiO2 calcined at 500 °C (M500) demonstrated the highest activity, around 76.9% conversion was achieved with 78.9% selectivity to hydrocarbon. The reaction proceed through second order kinetic with a rate constant of 0.0557 g−1trioleinh−1. The major product of the reaction were diesel range saturated and unsaturated hydrocarbon (60%) further the formation of in situ H2. It is interesting to observe that higher calcination temperature improve crystallinity and remove surface hydroxyls, meanwhile increase the acid density and medium strength acid site. The conversion of triolein increased linearly with the amount of medium strength acid sites. This result suggests that medium-strength acidity of catalyst is a critical factor in determining deoxygenation activities. In addition, the presence of mesopores allow the diffusion of triolein molecules and improve the selectivity. Hence, mesoporous TiO2 with Lewis acidity is a fascinating catalyst and hydrogen donor in high-value green fuel

Promoting deoxygenation of triglycerides via Co-Ca loaded SiO2-Al2O3 catalyst

Triglycerides and fatty acid derivatives can be converted to hydrocarbon-grade green diesel that are entirely fungible to the fossil fuels. In the present study, deoxygenation (DO) process of triolein was studied by using mesoporous SiO2-Al2O3 supported Co-Ca catalyst. The presence of active metals (Co-Ca) showed high DO activity exclusively via decarboxylation/decarbonylation (deCOx) pathways with maximum hydrocarbon n-(C8-C20) yield of 73%, and high selectivity of n-C15 and n-C17 fractions. This results suggested the acid-base active sites of catalyst provide selective deCOx pathway of triglycerides structure. In additional, the presence of high surface area of Co-Ca/ SiO2-Al2O3 enhance the metal dispersion for better accessment of large molecular reactant with catalyst during DO process. An optimum Co metal content (10 wt.%) for deCOx reaction was observed, while an excess Co content is not preferable due to tendency of cracking effect. The efficiency of Co-Ca/SiO2-Al2O3 was investigated by using non-edible feedstock (e.g. Ceiba oil and Sterculia oil) along with catalyst stability study were carried out. Resulst also indicated that degradation of DO activity was due to the formation of coke

Effect of reaction conditions on the lifetime of SAPO-34 catalysts in methanol to olefins process – A review

There is a rising demand for light olefins production to meet the increase in human population, burgeoning transportation network and rapid pace of industrialization. Methanol-to-olefins (MTO) conversion process is the most preferentially-selected route to synthesize olefins even though obtaining the high selectivity remains a challenge to this day. Methanol is industrially-produced via two-steps catalytic routes, viz. gasification of coal to syngas followed by syngas conversion. Due to the abundance of methanol, conversion of methanol to light olefins (ethylene and propylene) or polyolefins (polypropylene and high-density polyethylene) is most desired. Although, natural gas or syngas routes are well established and implemented at industrial level but still direct or indirect transformation of methanol to petrochemicals gained core interest. Significantly, the use of molecular sieves as a catalyst support or directly as a catalyst has been an area of active commercial developments for the past two decades. The engineered molecular sieves possess specialized topographical structure that can efficiently reduce the rate of coke deposition, enhance mass transport and improve the catalytic performance, viz. lifetime and olefins selectivity for methanol to olefins reaction. In this regard, the SAPOs molecular sieves are highly selective for the synthesis of ethylene and propylene. Among them, SAPO-34 molecular sieves exhibit the best performance for the MTO process. The current review highlights the importance of SAPO-34 supported catalysts in terms of lower chain hydrocarbon (C2–C4) selectivity, lower paraffinic and aromatic by-products ratio, catalyst stability, and renderability. In addition, the conditions causing the SAPO-34 catalysts deactivation such as coking, crystal size, water content, pressure metal incorporation, acid site strength, and influence of process conditions on triglyceride-based feeds are also thoroughly reviewed