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

Catalytic deoxygenation by H2-free single-step conversion of free fatty acid feedstock over a Co-Ag carbon-based catalyst for green diesel production

A family of activated carbon-supported Co-Ag catalysts, synthesised through incipient wetness impregnation, have been evaluated for the deoxygenation of palm fatty acid distillate (PFAD) and inedible feedstocks (jatropha oil and waste cooking oil) to green diesel. High deoxygenation efficiency and conversion of PFAD to hydrocarbon liquid products through decarboxylation/decarbonylation (deCOx) is observed, with Co(10wt.%)-Ag(5− 20wt.%)/AC exhibiting the greatest hydrocarbon (C8–C20) fractions yield of 92 % and 95 % (C15+C17) selectivity after 120 min reaction at 350 ◦C. These results suggested the synergistic effect between the active metals, Co-Ag, and the activated carbon support, creating acid-base Bronsted ¨ sites, which significantly facilitated the selective deCOx pathway of the fatty acid. The catalyst Co(10wt.%)-Ag(10wt.%)/AC was capable of deoxygenation the PFAD over eight cycles. Thus, it can be believed a potentially promising catalyst for the production of green diesel, at the same time providing economic opportunities and added value to the palm oil industry

Catalytic deoxygenation of waste cooking oil utilizing nickel oxide catalysts over various supports to produce renewable diesel fuel

The development of renewable diesel fuel from the deoxygenation of non-edible oil is an alternative to non-renewable fuels. Herein, the evaluation of catalytic deoxygenation of waste cooking oil (WCO) over supported Ni-based catalysts was investigated. A series of Ni-based catalysts supported on activated carbon (AC), reduced graphene oxide (rGO), and beta zeolite (Zeo) were prepared via the wet-impregnation method and later carbonised under N2 flow at 550 °C for 4 h. Addition of Ni to AC improves the good physicochemical properties of the catalyst, owing to the high number of acid-base sites, high surface area, smaller crystallite size, and high pore volume of the catalyst. From the catalytic results, Ni20/AC was the most active catalyst by giving 90% hydrocarbon yield and 89% selectivity towards n-(C15 + C17) under H2-free and solvent-free conditions for 3 h at 350 °C and 300 rpm. Furthermore, it was stable up to the fourth cycle with consistent hydrocarbon yield (85–87%) and 66–77% selectively towards n-(C15 + C17). Overall, Ni20/AC shows highly promising catalytic performance due to its good physiochemical properties and high catalyst stability

Kinetics and mechanisms of degradation of selected environmental pharmaceuticals by aqueous chlorination / Wan Nor Adira Wan Khalit

The occurrence of pharmaceuticals as pollutant in the environment has been widely reported across the world. It has been a growing concern due to it negative impacts of these pharmaceuticals on the ecosystem and living organism. During conventional water treatment processes, untreated pharmaceuticals are often exposed to chemical oxidation reaction during disinfection process. Among various disinfection methods, chlorination is one of the most commonly used methods. The reactive species in the chlorination process is hypochlorous acid (HOCl) which is known to react with organic pollutants. The main objectives of this study were to determine the second-order rate constants (kapp) for the reaction between selected pharmaceuticals with free available chlorine (FAC) and identification of the transformation by-products generated from the chlorination of selected pharmaceuticals. According to the identified transformation byproducts, the mechanism of the transformation pathway of selected pharmaceuticals in chlorination was elaborated. The efficiency of chlorination in the removal of selected pharmaceuticals in different matrices was also evaluated. The selected pharmaceuticals for this study were acebutolol and sotalol (β-blockers), mefenamic acid (nonsteroidal anti-inflammatory drugs), sulfacetamide and sulfanilamide (antibiotics). These pharmaceuticals have been frequently detected in the aquatic environment. In the kinetics study, kapp for the reaction between selected pharmaceuticals and FAC were determined at 25 ± 0.1 °C. The result indicated that the degradation of selected pharmaceuticals by free FAC was highly pH dependence at the selected pH range. At pH 6 to 8, it was found that kapp of Abt, Stl, Mfe, Sfa and Sfn was ranged from 0.03 to 0.19 M-1s-1, 0.93 to 0.65 M-1s-1, 16.4 to 4.35 M-1s-1, 4.50 to 4.50 M-1s-1 and 2.20 to 0.97 M-1s-1, respectively. The elimination of the selected pharmaceuticals in different water matrices (lake water, ground water and secondary effluent) showed that the efficiency of chlorination in the pharmaceuticals removal was retarded by high TOC and COD concentrations. Chlorination showed the highest efficiency in the removal of selected pharmaceuticals containing in ground water which has the lowest TOC and COD concentrations. However, in secondary effluent that containing higher concentrations of COD and TOC, the percentage removal of selected pharmaceuticals was relatively poor as compared with other water matrices. Characterization of the transformation by-products formed during the chlorination of selected pharmaceuticals was carried out using liquid chromatography coupled to quadrupole time-of-flight high resolution mass-spectrometry. The transformation by-products were determined after 24 h of FAC exposure. The result indicated that chlorination of pharmaceuticals could produce various transformation byproducts. Overall, 18 transformation by-products were identified for the selected pharmaceuticals. These transformation by-products were mainly formed through the hydroxylation, chlorination, oxidation and dealkylation reactions. In conclusion, this research showed that pharmaceuticals could react with HOCl during disinfection process. The reactivity of the selected pharmaceuticals towards the reaction with HOCl is highly pH dependent at the common pH range of natural water. Chlorination might remove some of the pharmaceuticals however its efficiency was depending on the characteristic of water matrices. Chlorination of pharmaceuticals was also found to form various transformation by-products

Development of supported nickel-based catalysts for deoxygenation of waste cooking oil to renewable fuel production

The development of renewable diesel fuel from the deoxygenation of non-edible oil is an alternative to non-renewable fuels. This study investigated the catalytic deoxygenation of waste cooking oil (WCO) over supported Ni-based catalysts. The deoxygenation of WCO was conducted using different types of supports: activated carbon (AC), reduced graphene oxide (rGO), and beta zeolite (Zeo). The addition of Ni to AC improves the physicochemical properties of the catalyst, owing to the high number of acid-base sites, high surface area, smaller crystallite size, and high pore volume of the catalyst. Based on the catalytic results, Ni20/AC was the most active catalyst, which achieved 90% hydrocarbon yield and 89% selectivity towards n-(C15+C17). Furthermore, it was stable up to the fourth cycle with consistent hydrocarbon yield (85-87%) and 66- 77% selectively towards n-(C15+C17). Further investigation was conducted to study the effect of bifunctional catalysts (NiLa, NiCe, NiFe, NiMn, NiZn, and NiW) supported on AC. High hydrocarbon yield above 60% with lower oxygenated species was found in the liquid product with the product selectively toward n-(C15+C17)-diesel fractions. The predominance of n-(C15+C17) hydrocarbons with concurrent production of CO and CO2 indicated that the deoxygenation pathway preceded via decarbonylation and decarboxylation mechanisms. For NiLa/AC, high deoxygenation activity with better n- (C15+C17) selectivity was obtained due to great synergistic interaction between La–Ni, and its compatibility of acid-base sites increased the removal of oxygenates. For the effect of La on the deoxygenation performance, it was found that a high percentage of La species would be beneficial in the removal of C-O bonded species. Furthermore, optimum deoxygenation activity of 88% hydrocarbon yield with 75% n-(C15+C17) selectivity was obtained over 20% La, which strongly evinced that La leads to more significant enhancement of deoxygenation activity. The NiLa/AC reusability study showed consistent deoxygenation with 80% hydrocarbon yield and 60% n-(C15+C17) hydrocarbons selectivity within six runs. As the NiZn/AC catalyst also showed high performance in deoxygenation activity, the optimization over a series of Ni20Znx/AC catalysts (X: 5–20 wt.%) was also studied. The Ni20Zn10/AC catalyst exhibited superior deoxygenation activity by yielding 86% hydrocarbons and 79% of n-(C15 + C17) selectivity. High deoxygenation activity is corroborated by the higher acidity and basicity strength of the catalyst and the oxygenate species removal that occurred via decarbonylation pathway. The Ni20Zn10/AC catalyst showed promising catalytic stability and reusability up to four runs with hydrocarbon yield (78 – 87%) and n-(C15 + C17) selectivity within the range of 43 – 70%, respectively. The decrease in the n-(C15 + C17) selectivity in the fourth cycle was due to the active metal species leaching and coking. In conclusion, all Ni-based catalysts demonstrated significant catalytic activity and reusability for green diesel 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

Catalytic deoxygenation of waste cooking oil utilizing nickel oxide catalysts over various supports to produce renewable diesel fuel

The development of renewable diesel fuel from the deoxygenation of non-edible oil is an alternative to non-renewable fuels. Herein, the evaluation of catalytic deoxygenation of waste cooking oil (WCO) over supported Ni-based catalysts was investigated. A series of Ni-based catalysts supported on activated carbon (AC), reduced graphene oxide (rGO), and beta zeolite (Zeo) were prepared via the wet-impregnation method and later carbonised under N2 flow at 550 °C for 4 h. Addition of Ni to AC improves the good physicochemical properties of the catalyst, owing to the high number of acid-base sites, high surface area, smaller crystallite size, and high pore volume of the catalyst. From the catalytic results, Ni20/AC was the most active catalyst by giving 90% hydrocarbon yield and 89% selectivity towards n-(C15 + C17) under H2-free and solvent-free conditions for 3 h at 350 °C and 300 rpm. Furthermore, it was stable up to the fourth cycle with consistent hydrocarbon yield (85–87%) and 66–77% selectively towards n-(C15 + C17). Overall, Ni20/AC shows highly promising catalytic performance due to its good physiochemical properties and high catalyst stability

Development of bimetallic nickel-based catalysts supported on activated carbon for green fuel production

In this work, the catalytic deoxygenation of waste cooking oil (WCO) over acid–base bifunctional catalysts (NiLa, NiCe, NiFe, NiMn, NiZn, and NiW) supported on activated carbon (AC) was investigated. A high hydrocarbon yield above 60% with lower oxygenated species was found in the liquid product, with the product being selective toward n-(C15 + C17)-diesel fractions. The predominance of n-(C15 + C17) hydrocarbons with the concurrent production of CO and CO2, indicated that the deoxygenation pathway proceeded via decarbonylation and decarboxylation mechanisms. High deoxygenation activity with better n-(C15 + C17) selectivity over NiLa/AC exposed the great synergistic interaction between La and Ni, and the compatibility of the acid–base sites increased the removal of oxygenated species. The effect of La on the deoxygenation reaction performance was investigated and it was found that a high percentage of La species would be beneficial for the removal of C–O bonded species. The optimum deoxygenation activity of 88% hydrocarbon yield with 75% n-(C15 + C17) selectivity was obtained over 20% of La, which strongly evinced that La leads to a greater enhancement of the deoxygenation activity. The NiLa/AC reusability study showed consistent deoxygenation reactions with 80% hydrocarbon yield and 60% n-(C15 + C17) hydrocarbon selectivity within 6 runs

One-pot decarboxylation and decarbonylation reaction of waste cooking oil over activated carbon supported nickel-zinc catalyst into diesel-like fuels

In this work, green diesel was generated via one-pot decarboxylation/decarbonylation (deoxygenation) reactions over a series of Ni20Znx/AC (X: 5–20 wt%) catalysts. The Ni20Zn10/AC catalyst exhibited superior deoxygenation reaction by yielding 86% hydrocarbons and 79% of n-(C15 + C17) selectivity, with the activity tending to undergo the decarbonylation pathway. Indeed, high deoxygenation activity is correlated with a higher acidity and basicity strength of the catalyst, and the removal of the oxygenates species occurred via decarbonylation pathways. The Ni20Zn10/AC catalyst showed a promising catalytic longevity and recyclability up until four runs, with a hydrocarbon yield of 78–87% and n-(C15 + C17) selectivity within the range of 43–70%. The decrease in the n-(C15 + C17) selectivity at the fourth cycle was due to leaching of active metal and the coking activity. The fuel properties of the green diesel (G100) were investigated, and it was revealed that the green diesel almost exhibited outstanding fuel properties (acid value, kinematic viscosity, flash point, cetane index, and calorific value) in comparison with ultra-low sulfur diesel (ULSD), suggesting that G100 can be used in vehicle engines without modification and has great potential for commercialization