Hydroxyapatite Catalysts Research Articles

An efficient and sustainable synthesis of morpholino-1,4-dihydropyridine-2,3-dicarboxylates using recyclable SeO2/HAp catalyst

• Excellent yields (95 to 98%) in short reaction times (less than10 min). • Superb reusable (8 times) catalyst 2.5 %SeO 2 /HAp. • Synthesis of novel morpholino-1,4-dihydropyridine-2,3-dicarboxylates analogues. • One-pot/four-component green solvent (ethanol) protocol. • Easy recovery catalyst and cost effective reagents. A novel, facile, incredibly stable, and environmentally benign Selenia-loaded hydroxyapatite (SeO 2 /HAp) catalysts have effectively synthesized. The catalyst material is characterized by different spectroscopic analyses like BET, TEM, SEM, P-XRD, and SEM-EDS. The nanomaterial catalytic activity was used to synthesize morpholino-1,4-dihydropyridine-2,3-dicarboxylates under mild reaction conditions. This greener approach exhibits several advantages: simplicity, low-cost, eco-friendly, simple work-up procedure, short reaction time (less than 10 min), minimizing wastes, greener safe solvent, simple purification, and excellent product yields (95–98%). Notably, the material could be detached from the reaction mixture using simple filtration and recycled for several periods without activity loss.

Decarbonization of Polluted Air by Solar‐Driven CO2 Conversion into Ethanol Using Polarized Animal Solid Waste as Catalyst

AbstractCO2 conversion to added value products using green processes in terms of source of energy, energy consumption, and/or management of raw materials obtained from waste materials are very attractive approaches for a modern sustainable society. In this work, such approaches are integrated, converting CO2 into ethanol by using polluted air as feeding gas. More specifically, recycled permanently polarized hydroxyapatite catalysts are prepared by applying a thermally stimulated polarization process to pork, beef, and chicken scrapped bones. The recycled bone catalysts are used to perform a series of reactions fed with polluted air and only powered with solar energy using a solar furnace. Reactions are conducted for 5 days and 1 month. Results demonstrate significant decarbonization, converting CO2 into valuable chemical products with high selectivity toward ethanol (up to 99.6%).

Suitability of different supported Ru, Pt and Ni catalysts for the hydrogenolysis of sorbitol

In this article, the results of sorbitol hydrogenolysis (15% aq. solution), done in an autoclave reactor, over Ru, Pt and Ni loaded on SBA15, carbon coated SBA15 (SBA15C), activated carbon (AcC), Na–Y, Fly Ash (FA) and hydroxyapatite (HAP) catalysts by our group, were compared to find the best metal-support combinations. The metal loading was 1 wt% for Ru and Pt, 6 wt% for Ni and the catalysts' preparations were carried out by impregnation of respective salts. The catalysts were characterized with nitrogen and hydrogen adsorption measurements and X-ray diffraction. Addition of a base (Calcium hydroxide) to the reactants' mixture increased the overall conversion and selectivities of the glycols, ethylene glycol (EG) and 1,2-propylene glycol (PG). The catalysts’ performance at 60 bar and 220 °C with the presence of base (B), evaluated by the yield of glycols (PG + EG), showed the following order:Ni/Na–Y > Ru/AcC ∼ Ru/SBA15C > Ni/HAP ∼ Ru/SBA15 > Ni/SBA15 > Ru/Na–Y > Ni/FA ∼ Ni/AcC and the yields were 57, 40, 39, 33, 31, 29, 26, 22 and 21 wt%, respectively.Na–Y appeared to be the best support, especially for Ni metal; AcC and SBA15C were good supports for Ru and Pt respectively. Reusability studies revealed that Ni on HAP was the best catalyst and exhibited only a small deactivation during four runs of loading it.

Vapor-phase intramolecular aldol condensation of 2,5-hexanedione over calcium hydroxyapatite catalyst

Vapor-phase production of 3-methylcyclopent-2-en-1-one (MCP) via intramolecular aldol condensation of 2,5-hexanedione (HD) was performed over calcium hydroxyapatite (HAP) catalysts aged under various conditions. The aging temperature and time of the as-prepared apatite precipitate significantly affected the catalytic activity of the resulting HAP catalyst by influencing its residual carbonate and nitrate species and specific surface area. The HAP aged at a temperature between 50 and 200 ºC showed the highest catalytic activity with a high MCP selectivity of ca. 95%. However, serious deactivation was observed in an N2 carrier gas flow due to coke formation. The modification of the HAP catalyst with silver and the utilization of H2 as a carrier gas significantly reduced the coke formation and improved the catalytic stability during aldol condensation of HD to MCP.

Highly facile Co2+ and Mn3+ species supported on hydroxyapatite catalyst for carbon monoxide oxidation at a lower temperature

Highly facile Co2+ and Mn3+ species supported on hydroxyapatite catalyst for carbon monoxide oxidation at a lower temperature

Tailorable Nanoporous Hydroxyapatite Scaffolds for Electrothermal Catalysis.

Polarized hydroxyapatite (HAp) scaffolds with customized architecture at the nanoscale have been presented as a green alternative to conventional catalysts used for carbon and dinitrogen fixation. HAp printable inks with controlled nanoporosity and rheological properties have been successfully achieved by incorporating Pluronic hydrogel. Nanoporous scaffolds with good mechanical properties, as demonstrated by means of the nanoindentation technique, have been obtained by a sintering treatment and the posterior thermally induced polarization process. Their catalytic activity has been evaluated by considering three different key reactions (all in the presence of liquid water): (1) the synthesis of amino acids from gas mixtures of N2, CO2, and CH4; (2) the production of ethanol from gas mixtures of CO2 and CH4; and (3) the synthesis of ammonia from N2 gas. Comparison of the yields obtained by using nanoporous and nonporous (conventional) polarized HAp catalysts shows that both the nanoporosity and water absorption capacity of the former represent a drawback when the catalytic reaction requires auxiliary coating layers, as for example for the production of amino acids. This is because the surface nanopores achieved by incorporating Pluronic hydrogel are completely hindered by such auxiliary coating layers. On the contrary, the catalytic activity improves drastically for reactions in which the HAp-based scaffolds with enhanced nanoporosity are used as catalysts. More specifically, the carbon fixation from CO2 and CH4 to yield ethanol improves by more than 3000% when compared with nonporous HAp catalyst. Similarly, the synthesis of ammonia by dinitrogen fixation increases by more than 2000%. Therefore, HAp catalysts based on nanoporous scaffolds exhibit an extraordinary potential for scalability and industrial utilization for many chemical reactions, enabling a feasible green chemistry alternative to catalysts based on heavy metals.

Study on the promotional effect of lanthana addition on the performance of hydroxyapatite-supported Ni catalysts for the CO2 methanation reaction

The performance of nickel supported on lanthana-modified hydroxyapatite (HAP) catalysts is investigated in the CO2 methanation. The addition of La (1–6.6 wt%) leads to a surface enrichment following a sequential multilayer deposition model. Moreover, La addition systematically improves the dispersion of Ni particles and their reducibility, which in turn increases spectacularly the amounts of basic sites and their thermal stability. Such physicochemical changes impact positively on the activity of the catalysts in CO2 methanation. The estimated turnover frequency (TOF) suggest that the small Ni particles are the most efficient. The latter seem to provide a large density of very active defects on Ni-La2O3 interface. The optimized catalyst proves to be highly resistant to deactivation during 100 h time-on-stream (TOS). The samples were also assayed as dual function materials (DFMs) for CO2 adsorption and methanation. A scheme is proposed to describe the different steps involved in a CO2 adsorption/hydrogenation cycle.

Optimization of biodiesel production from waste cooking oil using α-Fe2O3/HAP catalyst via simultaneous esterification-transesterification reaction

ABSTRACT The study aimed to optimize a waste-cooking oil-based biodiesel production process using α-Fe2O3/Hydroxyapatite (HAP) catalyst from natural iron sand and phosphate rocks. The parameters investigated in this study were reaction temperature, methanol:WCO molar ratio, and catalyst weight. Response surface methodology (RSM) with central composite design (CCD) was used to design the experiment, and a model in the form of a quadratic equation was later generated based on the investigated parameters and the observed biodiesel yield response. The model was subjected to ANOVA analysis to determine its validity and the influence of the investigated parameters on the observed response. The results showed that the catalyst weight was the only parameter significantly influencing the biodiesel yield, although the reaction temperature was concluded to be borderline significant. The optimal reaction condition suggested was 70°C reaction temperature with 3.68%w/w catalyst weight and 10.47 mol/mol methanol:WCO molar ratio to achieve 93.96% biodiesel yield.

Efficient hydrodeoxygenation of lignocellulose derivative oxygenates to aviation fuel range alkanes using Pd-Ru/hydroxyapatite catalysts

Bimetallic Pd-Ru/ hydroxyapatite (HAP) catalysts were developed together with Zirconium phosphate (ZrP) to prepare aviation fuel range hydrocarbons by one-pot HDO from lignocellulose-derived C15 oxygenate. The effects of the catalyst composition, reaction time, initial H2 pressure and reaction temperature on the HDO were explored. 84.24% C8-C15 alkanes could be obtained by Pd0.6-Ru1.8/HAP at 150 °C, 4 MPa H2. The HDO pathway and the stability of the catalyst were also investigated. To explore the synergy of bimetals and the efficiency of the catalysts, a series of characterizations were conducted. The results verified that the bimetallic catalyst had a better adsorption capacity for the substrate, and the ruthenium external electron density raised due to the introduction of palladium, thereby enhancing the hydrodeoxygenation activity of the catalyst.

PO4 3- Coordinated Robust Single-Atom Platinum Catalyst for Selective Polyol Oxidation.

Achieving efficient catalytic conversion over a heterogeneous catalyst with excellent resistance against leaching is still a grand challenge for sustainable chemical synthesis in aqueous solution. Herein, we devised a single-atom Pt1 /hydroxyapatite (HAP) catalyst via a simple hydrothermal strategy. Gratifyingly, this robust Pt1 /HAP catalyst exhibits remarkable catalytic selectivity and catalyst stability for the selective oxidation of C2 -C4 polyols to corresponding primary hydroxy acids. It is found that the Pt-(O-P) linkages with strong electron-withdrawing function of PO4 3- (Pt1 -OPO4 3- pair active site) not only realize the activation of the C-H bond, but also destabilize the transition state from adsorbed hydroxy acids toward the C-C cleavage, resulting in the sharply increased selectivity of hydroxy acids. Moreover, the strong PO4 3- -coordination effect provides electrostatic stabilization for single-atom Pt, ensuring the highly efficient catalysis of Pt1 /HAP for over 160 hours with superior leaching resistance.

Highly dispersed silver nanoparticles supported on a hydroxyapatite catalyst with different morphologies for CO oxidation

The well confinement of nano-Ag NPs not only decreased their agglomeration with the SMSI effect but also significantly improved their dispersion in catalytic reactions.

Au nanoparticles loaded Hydroxyapatite catalyst prepared from waste eggshell: synthesis, characterization and application in VOC removal

Eggshell, which is made almost entirely of calcium carbonate, is among the most abundant waste materials from poultry production. In 2018, the worldwide egg production exceeded 78 million metric tons which contributed to over 8 million metric tons of eggshell waste. However, this waste can be converted into useful materials for several industrial applications. Herein, hydroxyapatite (HAp) of fine particles was prepared using a green synthesis procedure in water medium from eggshell waste. Then, HAp was utilized as support material for loading different contents of Au nanoparticles (0.2 and 0.5 wt%). The materials were characterized by Brunauer-Emmett-Teller (BET) surface area analysis, Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), X-ray diffraction (XRD). The prepared catalysts were used for VOCs oxidation of formaldehyde in continuous flow and humid condition. In this study, Au/HAp (0.2 wt%) exhibited superior catalytic activity with good low-temperature reproducibility and high dispersion of particles on the surface of hydroxyapatite. Hence, hydroxyapatite prepared from eggshell waste is considered as a promising support material for noble metal catalysts for VOCs oxidation.

Successive Vapor-Phase Guerbet Condensation of Ethanol and 1-Butanol to 2-Ethyl-1-hexanol over Hydroxyapatite Catalysts in a Flow Reactor

Successive Vapor-Phase Guerbet Condensation of Ethanol and 1-Butanol to 2-Ethyl-1-hexanol over Hydroxyapatite Catalysts in a Flow Reactor

Removal of Various Hazardous Materials Using a Multifunctional Biomass-Derived Hydroxyapatite (HAP) Catalyst and Its Antibacterial Effects

In the present study, oyster shells, a cause of environmental pollution, were employed effectively to synthesize hydroxyapatite (HAP) by facile oxidation and phosphorylation. The ability of HAP to adsorb various metal cations and inhibit bacterial growth was validated. The biomass-derived HAP catalyst exhibited high metal cation adsorption in water at room temperature and under various acidic conditions (M = Cr, Mn, Ni, Cu, Cd, Ba, and Pb). HAP was demonstrated to have a maximum removal efficiency of 92.8% for the heavy metal Pb. Even under different pH conditions, HAP was demonstrated to be effective for the removal of three harmful heavy metals, Cr, Cd, and Pb, with a particularly high removal efficiency demonstrated for Pb under all conditions (average removal efficiency of Cr: 63.0%, Cd: 59.9%, and Pb: 91.6%). In addition, HAP had a significant influence on phosphate ion adsorption in aqueous solution, eliminating 98.1% after 3 min. Furthermore, biomass-derived HAP was demonstrated to have significant antibacterial activity against E. coli and S. aureus (5 mM: 74% and 78.1%, 10 mM: 89.6% and 96.0%, respectively).

One-Pot Synthesis of a Highly Active and Stable Ni-Embedded Hydroxyapatite Catalyst for Syngas Production via Dry Reforming of Methane

One-Pot Synthesis of a Highly Active and Stable Ni-Embedded Hydroxyapatite Catalyst for Syngas Production via Dry Reforming of Methane

1-08 種々のCa/Pを有するハイドロキシアパタイトを用いたNi担持触媒のバイオマスモデルタール低温分解活性

1-08 種々のCa/Pを有するハイドロキシアパタイトを用いたNi担持触媒のバイオマスモデルタール低温分解活性

Optimasi Kondisi Proses Sintesis Biodiesel Berbasis Reaksi Esterifikasi Palm Fatty Acid Distillate Dengan Katalis Cu-Hidroksiapatit Dari Limbah Tulang Ikan

Biodiesel is an alternative fuel to a diesel engine that can replace or reduce the use of petroleum diesel. PFAD (Palm Fatty Acid Distillate) is a by-product of physical refining of crude palm oil products and is contained of free fatty acid (FFA) more than 85 wt.%. Esterification is a chemical reaction used to produce biodiesel from feedstocks with high FFA. Hydroxyapatite derived from waste fish bones has been effectively utilized as a support for preparation of the heterogeneous copper acid catalyst. The Copper- Hydroxyapatite catalyst has been prepared through wet-impregnation.This study intends to produce biodiesel with Cu- Hydroxyapatite catalyst derived from fishbone waste in esterification of PFAD and methanol. Esterification reaction parameters were varied to obtain the maximum yield of biodiesel. Optimization of esterification reaction parameters such as methanol to PFAD ratio, catalyst loading, and reaction temperature was carried out by Response Surface Methodology-Central Composite Design (RSM-CCD). The optimum yield obtained using regression models were found to be reaction temperature 62oC, catalyst to PFAD weight 1,82 wt.%, and PFAD to methanol molar ratio 1:8,28. The reaction under the optimum condition predicted at 92,52% of biodiesel yield.

Optimization of permanently polarized hydroxyapatite catalyst. Implications for the electrophotosynthesis of amino acids by nitrogen and carbon fixation

The enhanced catalytic activity of permanently polarized hydroxyapatite, which is achieved using a thermally stimulated polarization process, largely depends on both the experimental conditions used to prepare crystalline hydroxyapatite from its calcium and phosphate precursors and the polarization process parameters. A mineral similar to brushite, which is an apatitic phase that can evolve to hydroxyapatite, is found at the surface of highly crystalline hydroxyapatite. It appears after chemical precipitation and hydrothermal treatment performed at 150 °C for 24 h followed by a sinterization at 1000 °C and a polarization treatment by applying a voltage of 500 V at high temperature. Both the high crystallinity and the presence of brushite-like phase on the electrophotocatalyst affect the nitrogen and carbon fixation under mild reaction conditions (95 °C and 6 bar) and the synthesis of glycine and alanine from a simple gas mixture containing N2, CO2, CH4 and H2O. Thus, the Gly/Ala ratio can be customized by controlling the presence of brushite on the surface of the catalyst, enabling to develop new strategies to regulate the production of amino acids by nitrogen and carbon fixation.

Exceptional performance of gold supported on fluoridated hydroxyapatite catalysts in CO-cleanup of H2-rich stream: High activity and resistance under PEMFC operation conditions

Proton-exchange-membrane fuel cells (PEMFCs) appear to be the most promising solution for future automotive applications. Facing the lack of efficient hydrogen storage and transportation solutions, current research is focused on the development of on-board catalytic reformers. In this strategy, the purity of hydrogen stream is still an unresolved issue that needs to be addressed in order to avoid poisoning of the Pt electrodes of PEMFC.Here we report the extraordinary performance of gold supported on fluorine-substituted hydroxyapatite (HAP) catalysts in the CO preferential oxidation (COPROX) process. At 80 °C, the optimized catalyst (Au/F-(1)) proves to be highly active, selective (showing a CO conversion (XCO) of 100 % and selectivity towards CO2 production (SCO2) close to 62 %) and very resistant to deactivation, even in the presence of H2O (15 %) and CO2 (20 %). In addition, these results were obtained at relatively high weight hourly space velocity (WHSV: 60,000 cm3 g−1 h−1). It should be highlighted that our catalysts clearly outperform state-of-the-art gold catalysts. Our discovery introduces Au/F(x)-HAP catalysts as a viable solution for an effective elimination of CO to feed PEMFCs with CO-free hydrogen streams.

The Role of the Surface Acid-Base Nature of Nanocrystalline Hydroxyapatite Catalysts in the 1,6-Hexanediol Conversion.

Hydroxyapatite is known to have excellent catalytic properties for ethanol conversion and lactic acid conversion, and their properties are influenced by the elemental composition, such as Ca/P ratio and sodium content. However, few reports have been examined for the surface acid–base nature of hydroxyapatites containing sodium ions. We prepared nanocrystalline hydroxyapatite (Ca-HAP) catalysts with various Ca/P ratios and sodium contents by the hydrothermal method. The adsorption and desorption experiments using NH3 and CO2 molecules and the catalytic reactions for 2-propenol conversion revealed that the surface acid–base natures changed continuously with the bulk Ca/P ratios. Furthermore, the new catalytic properties of hydroxyapatite were exhibited for 1,6-hexanediol conversion. The non-stoichiometric Ca-HAP(1.54) catalyst with sodium ions of 2.3 wt% and a Ca/P molar ratio of 1.54 gave a high 5-hexen-1-ol yield of 68%. In contrast, the Ca-HAP(1.72) catalyst, with a Ca/P molar ratio of 1.72, gave a high cyclopentanemethanol yield of 42%. Both yields were the highest ever reported in the relevant literature. It was shown that hydroxyapatite also has excellent catalytic properties for alkanediol conversion because the surface acid–base properties can be continuously controlled by the elemental compositions, such as bulk Ca/P ratios and sodium contents.