Synthesis and catalytic activity of hydrationdehydration treated clamshell derived CaO for biodiesel production

Biodiesel has gained interest of most researchers recently as an alternative for fossil diesel fuels in promoting environmentally sustainable fuels. With the presence of base catalyst, biodiesel can be easily produced via transesterification of triglyceride with alcohol under mild reaction conditions. Utilization of green catalysts from natural waste shells for biodiesel synthesis is capable of reducing the cost of catalyst which is beneficial to overall production cost. In this study, we have developed a modified CaO catalyst from natural waste clamshell (Meretrix meretrix) via hydration–dehydration treatment for transesterification process. The effects of hydration duration on clamshell were investigated to achieve the most optimum characteristic and catalytic activity. The surface area and the basicity of the treated catalyst increased extensively with prolonged hydration duration technique. By prolonging the water treatment process, it shall allow more formation of Ca(OH)2 which then has promoted the formation of Bronsted base sites for higher basicity. The catalytic activity of hydration–dehydration treated catalysts were found increased in the following order CS-CaO12h > CS-CaO9h > CS-CaO6h > CS-CaO3h > CS-CaO1h. The triglyceride conversion was as high as 98% when utilizing CS-CaO12h under reflux conditions of methanol: oil molar ratio of 9:1, catalyst amount is 1 wt% and 2 h of reaction time

Synthesis of clamshell derived Ca(OH)2 nano-particles via simple surfactant-hydration treatment

Recently, calcium hydroxide (Ca(OH)2) nanoparticles derived from calcium oxide (CaO) has been getting attention from researchers as heterogeneous catalyst for several chemical reaction such as: transesterification, chemisorbents for toxic gases and cracking-decarboxylation process. Ca(OH)2 in nano-crystal structures exhibit superior characteristics which enhance the reaction. In Malaysia, clam species (Meretrix meretrix) are abundantly available in backwater and estuaries along the coast. It is a green material that composed of at least 95% of calcium for CaO production. In the present study, a green solid base Ca(OH)2 nanoparticles was prepared using waste clamshell (M. meretrix) via low cost wet-chemical route. The effects of wet-surfactant treatments (ethylene glycol (EG), diethyl ether (DE) and N-Cetyl-N,N,N-trimethylammonium bromide (CTAB)) on clamshell derived CaO (CS-CaO) were examined. Furthermore, the physicochemical properties of CS-CaO and surfactant treated Ca(OH)2 were analyzed using X-ray fluorescence spectrometer (XRF), X-ray diffraction spectroscopy (XRD), fourier transform spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) technique, temperature program desorption of carbon dioxide (TPD-CO2), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results showed that surfactant treatments are capable of enhancing properties of clamshell derived nano-Ca(OH)2 materials such as particle sizes, surface area and basicity. Among the surfactants, EG rendered the most significant effect on the clamshell-derived material, with surface area of 78.38 m2 g−1, basicity of 4658.8 μmol/g and nanoparticle sizes at 25–42 nm

A new route for the synthesis of La-Ca oxide supported on nano activated carbon via vacuum impregnation method for one pot esterification- transesterification reaction

Advanced carbon nanorod promoted binary CaO-La2O3 system with improved physical properties, tailored surface morphology and chemistry were developed in vacuum-impregnating methods. The nanostructured catalyst (CaO–La2O3/AC nanocatalyst) was prepared to convert high FFA waste cooking oil into biodiesel via one step esterification-transesterification reaction. The novel catalyst was characterized by FTIR, SEM, XRD, TGA, BET, TPD-CO2 and TPD-NH3. The high catalytic activity of the nanocatalyst was mainly depends on the high acid and basic density of active sites that contributed from the synergic effect between mesoporous carbon and binary metallic system, which allowed more occurrence of simultaneous esterification-transesterification process of high FFA waste oil without additional pretreatment step. Result showed maximum 98.6±0.5% with acid value 0.4±0.5 mg KOH/g of triglyceride conversion under optimal condition at 3% of catalyst, methanol:oil ratio of 16:1, 100 °C within 4h of reaction. Furthermore, bi-metallic catalyst with stable carbon nanorod support capable to maintained high reusability with high FAME yield (> 98%) with low acid value (<0.5 mg KOH/g) for 5 cycles

Catalytic hydrothermal liquefaction of empty fruit bunch in subcritical water over bimetallic modified zeolite

Catalytic hydrothermal liquefaction of empty fruit bunch (EFB) with no added H2 effectively produces biomass derived fuel or known as bio-oil. In this study, a bimetallic modified zeolite (BaNi, BaLa and BaCe/CHZSM5) catalyst with a series of dosage ratio (1:1, 1:2 and 2:1) was used for the EFB conversion to bio-oil. Ni, La and Ce addition to the Ba/CHZSM5 showed significant changes on the physicochemical properties of catalysts and exhibited enhanced catalytic performance. The activity-structure correlation revealed that EFB conversion and bio-oil yield were favoured on bimetallic modified CHZSM5 and the most effective catalyst was Ba1La2/CHZSM5. Brunauer–Emmett–Teller (BET) surface area measurement and temperature programmed desorption of ammonia (TPD-NH3) results confirmed that high surface area and rich acidic sites of Ba1La2/CHZSM5 catalyst eventually enhanced the catalytic activity in HTL of EFB. Comparing to other bimetallic modified catalyst, the desirable aromatic and aliphatic hydrocarbon also predominated over Ba1La2/CHZSM5 catalysed reaction which demonstrated that this catalyst have a good ability in produce high quality of bio-oil with less oxygenated compounds

Single-atom catalysts: A review of synthesis strategies and their potential for biofuel production

Biofuels have been derived from various feedstocks by using thermochemical or biochemical procedures. In order to synthesise liquid and gas biofuel efficiently, single-atom catalysts (SACs) and single-atom alloys (SAAs) have been used in the reaction to promote it. SACs are made up of single metal atoms that are anchored or confined to a suitable support to keep them stable, while SAAs are materials generated by bi-and multi-metallic complexes, where one of these metals is atomically distributed in such a material. The structure of SACs and SAAs influences their catalytic performance. The challenge to practically using SACs in biofuel production is to design SACs and SAAs that are stable and able to operate efficiently during reaction. Hence, the present study reviews the system and configuration of SACs and SAAs, stabilisation strategies such as mutual metal support interaction and geometric coordination, and the synthesis strategies. This paper aims to provide useful and informative knowledge about the current synthesis strategies of SACs and SAAs for future development in the field of biofuel production

Effective catalytic deoxygenation of palm fatty acid distillate for green diesel production under hydrogen-free atmosphere over bimetallic catalyst CoMo supported on activated carbon

Palm fatty acid distillate (PFAD) is considered as an inedible and renewable feedstock for the production of green diesel. In the current study, green diesel was successfully synthesised via catalytic deoxygenation of PFAD in an environment free of H2 using a mesoporous activated carbon (AC) supported CoMo catalyst with various molybdenum (Mo) concentrations (5–20 wt%). Based on the study results, bimetallic catalyst Co10Mo10/AC formulation exhibited excellent catalytic performance with 92% hydrocarbon components (C8-C20) yield and 89% selectivity for n-(C15 + C17) with a total acid number of 24 mg KOH mg−1 . Based on a comparison study with various supports (AC, γ-Al2O3, TiO2), the AC-supported CoMo catalyst showed higher deoxygenation activity than both Co10Mo10/γ-Al2O3 and Co10Mo10/TiO2 owing to the super acid-base sites as a result of synergism between the CoMo and AC support. The Co10Mo10/AC catalyst demonstrated excellent stability during the study as it maintained the hydrocarbon components yield and selectivity of n-(C15 + C17) > 80% until the sixth run

Structural and catalytic studies of Mg1-xNixO nanomaterials for gasification of biomass in supercritical water for H2-rich syngas production

Nowadays, catalytic supercritical water gasification (SCWG) is undoubtedly used for production of H2-rich syngas from biomass. The present study reported the synthesis and characterisation of Mg1-xNixO (x ¼ 0.05, 0.10, 0.15, 0.20) nanomaterials that were obtained via self-propagating combustion (SPC) method, and catalysed the SCWG for the first time. It had found that increased the nickel (Ni) content in the catalyst reduced the crystallite size, thus, increased the specific surface area, which influenced the catalytic activity. The specific surface area followed the order of Mg0.95Ni0.05O (36.2 m2 g1 ) < Mg0.90Ni0.10O (58.9 m2 g1 ) < Mg0.85Ni0.15O (63.6 m2 g1 ) < Mg0.80Ni0.20O (67.9 m2 g1 ). From the Rietveld refinement, the Ni that was successfully partial substituted in the cubic crystal structure of MgO resulting in a cell contraction which ascribed the reduction of crystallite size. Increased the amount of Ni also narrowed the pore size distribution ranging between 4.17 nm and 6.23 nm, as well as increased the basicity active site up to 5741.0 mmol g1 at medium basic strength. All the synthesised nanocatalysts were catalysed the SCWG of OPF (oil palm frond) biomass. Among them, the mesoporous Mg0.80Ni0.20O nanocatalyst exhibited the highest total gas volume of 193.5 mL g1 with 361.7% increment of H2 yield than that of the non-catalytic reaction

Single-step catalytic deoxygenation-cracking of tung oil to bio-jet fuel over CoW/silica-alumina catalysts

Bifunctional Co-W catalysts with variable Co-W dosages on silica-alumina (SA) were prepared and tested for the catalytic deoxygenation-cracking of tung oil (TO) for the production of jet fuel (n-(C10-C16)) fractions. The CoW/SA catalyst appeared to be most active (hydrocarbon yield = 69%, jet fuel selectivity = 60%) and outperformed the monometallic Co and W analogues. Based on the effect of metal dosage, Co– and W-rich catalysts do not provide a workable approach in enhancing deoxygenation-cracking of the TO for jet fuel production, and overly cracking can be successfully controlled at lower metal dosages (5 wt% Co, 10 wt% W). The CoW/SA reusability study showed a consistent deoxygenation-cracking ability for four runs with hydrocarbon yields within the range of 77–84% and 64–77% jet fuel selectivity. GCMS analysis and physicochemical properties of TO oil fuel (TO-gasoline, TO-jet, TO diesel) confirmed that rich aromatic species in TO-diesel negatively affected the quality of the fuels. TO-fuels with a short chain had better combustion properties than those with a longer chain hydrocarbon. The TO-jet qualities are complied with standard Jet A-1 in accordance to ASTM D1655 and DEF STAN 91–91 specification standards. The TO-jet also exhibited excellent cold properties and superior combustion characteristic than Jet A-1

Catalytic ketonization of palmitic acid over a series of transition metal oxides supported on zirconia oxide-based catalysts

Modification of a ZrO2 based catalyst with selected transition metals dopants has shown promising improvement in the catalytic activity of palmitic acid ketonization. Small amounts of metal oxide deposition on the surface of the ZrO2 catalyst enhances the yield of palmitone (16-hentriacontanone) as the major product with pentadecane as the largest side product. This investigation explores the effects of addition of carefully chosen metal oxides (Fe2O3, NiO, MnO2, CeO2, CuO, CoO, Cr2O3, La2O3 and ZnO) as dopants on bulk ZrO2. The catalysts are prepared via a deposition–precipitation method followed by calcination at 550 °C and characterized by XRD, BET-surface area, TPD-CO2, TPD-NH3, FESEM, TEM and XPS. The screening of synthesized catalysts was carried out with 5% catalyst loading onto 15 g of pristine palmitic acid and the reaction carried out at 340 °C for 3 h. Preliminary studies show catalytic activity improvement with addition of dopants in the order of La2O3/ZrO2 < CoO/ZrO2 < MnO2/ZrO2 with the highest palmitic acid conversion of 92% and palmitone yield of 27.7% achieved using 5% MnO2/ZrO2 catalyst. Besides, NiO/ZrO2 exhibits high selectivity exclusively for pentadecane compared to other catalysts with maximum yield of 24.9% and conversion of 64.9% is observed. Therefore, the changes in physicochemical properties of the dopant added ZrO2 catalysts and their influence in palmitic acid ketonization reaction is discussed in detail

In-situ operando and ex-situ study on light hydrocarbon-like-diesel and catalyst deactivation kinetic and mechanism study during deoxygenation of sludge oil

Deoxygenation is a highly significant means of generating oxygen-free hydrocarbon fuels from liquid biomass. This study will deoxygenate sludge palm oil (FFA % = 42.35%) in an H2-free atmosphere through a series of Mn-Co supported AC catalysts (MnO0.5CoO0.5/AC, Mn0.5Co0.5S/AC and Mn0.5Co0.5P/AC). The XAS in-situ results confirm that the preparation method of formation the catalyst structure was successful. The catalytic results show that by oligomerizing unsaturated fatty acids produced during Diels-Alder reactions or radical additions, the MnO0.5)CoO0.5/AC can largely enhance the production of heavy products. It is a straightforward process to transform these heavy products into coke species, which enables the rapid deactivation of the catalyst. This study additionally showed that AC-supported sulphide and phosphide Mn-Co catalysts are hugely beneficial for steadily and reliably acquiring an above-average yield of diesel-range hydrocarbons at substantially reduced temperatures whilst simultaneously effectively impeding catalyst deactivation during deoxygenation. The deactivation kinetic study conform that the deactivation happens by the coke formation and flow the second order deactivation