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1.
Environ Sci Pollut Res Int ; 30(55): 117829-117845, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37875756

RESUMO

Global energy demand has drastically increased due to urbanization and industrialization; thus, developing alternative renewable energy sources is urgently required. In the present work, upgrading the pyrolytic oil (PO) derived from fresh palm fruit was performed by the catalytic in situ hydrodeoxygenation (in situ HDO) process. Preparation of nickel-doped HZSM-5 zeolite (SiO2/Al2O3 = 40) was achieved by incipient wetness impregnation techniques using different weight percents of nickel dopant into HZSM-5. Nickel-doped HZSM-5 zeolite (Ni-HZSM-5) was further subjected to chemical reduction for 5 h in the oxygen-free environment (10% H2 and 90% N2) at 550 °C. The structural properties showed a potential reduction of NiO-HZSM-5 to Ni-HZSM-5, enhancing the catalytic potential. The morphological characterizations showed spherical-shaped Ni agglomerated onto HZSM-5. Acidity and oxygen contents in the pyrolytic oil were achieved by catalyst-aided HDO process at 220 °C for 6 h using methanol as a hydrogen donor. The catalytically upgraded pyrolytic oil (UPO) was analyzed for density, HHV, CHNO, and TGA. The best upgrading oil was distilled following ASTM D86 to separate gasoline, kerosene, and diesel. The acidity, density, HHV, and viscosity were measured before and after the upgradation processes. The results showed the potential impact of Ni with 10% doped on HZSM-5 on HDO reaction and illustrated the lowest oxygen content in upgraded pyrolytic oil products. Considerable decrease in viscosity and density level indicated that in situ HDO not only reduced oxygen content but also cracked pyrolytic oil to small molecules. The distilled product of upgrading oil was higher than pyrolytic oil by approximately 15% in volume. The viscosity, density, and HHV were under standard specifications of kerosene and diesel, except for acidity. However, the acidity was reduced by over 60% compared with raw material.


Assuntos
Níquel , Zeolitas , Níquel/química , Querosene , Dióxido de Silício , Oxigênio , Catálise , Biocombustíveis
2.
Int J Biol Macromol ; 225: 899-910, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36403762

RESUMO

Silver nanoparticles (AgNPs)/carboxylated cellulose nanocrystals (Ag-cCNC) from Eucalyptus pulp were prepared using a three-step process. The cCNC were synthesized by oxidation of CNC from Eucalyptus pulp with ammonium persulfate, followed by a hydrothermal reaction to form Ag-cCNC. The Ag-cCNC was then characterized with respect to Ag+ release, flow behavior, and anticancer activity for potential applications in biomedicine and drug delivery. AgNPs with particle sizes in the range of 16.25 ± 7.83 to 21.84 ± 7.21 nm were uniformly embedded on the surface of the cCNC. The Ag-cCNC exhibited a slow and controllable release of Ag+ at a rate of 0.02 % per day for 28 days. Ag+ release was best described by the Korsmeyer-Peppas model based on non-Fickian diffusion. The Ag-cCNC at 200 µg/mL exerted antiproliferative activity in MCF-7 human breast cancer cells with 1.01 % ± 0.35 % cell viability and was non-toxic against normal Vero cells with 90 % viability. In contrast, the chemotherapeutic drug melphalan exhibited cytotoxic effects against both MCF-7 and Vero cells. The Ag-cCNC samples showed shear thinning properties with a pseudoplastic fluid behavior, indicating that Ag-cCNCs are suitable for drug delivery by injection.


Assuntos
Antineoplásicos , Nanopartículas Metálicas , Animais , Chlorocebus aethiops , Humanos , Nanopartículas Metálicas/química , Prata/farmacologia , Prata/química , Células Vero , Celulose/química , Antineoplásicos/farmacologia
3.
Environ Sci Pollut Res Int ; 30(39): 90298-90317, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36357757

RESUMO

Visible-light active La-Fe-SrTiO3 (La0.01Sr0.99Fe0.01Ti0.99O3) photocatalysts were synthesized via a dynamic hydrothermal route under different NaOH concentrations (2, 3, 4, 5, and 6 M). The results showed that altering NaOH concentrations changed the physicochemical characteristics of the materials. Namely, the decrease in particle size was observed when the NaOH levels were increased. The specific surface area of the photocatalysts changed with an increased concentration of NaOH, and the maximum value was 17.10 m2/g in 5 M of NaOH. The crystal structure of all prepared samples remained unaffected when altered the NaOH concentration or when incorporated La and Fe in the lattice of SrTiO3. Namely, all samples synthesized under various NaOH concentrations crystallized and maintained in the standard cubic perovskite structure of SrTiO3. The increased NaOH concentration slightly altered the absorption wavelength towards a longer wavelength region. The La atom, replacing some Sr2+ in the structure of modified SrTiO3, was confirmed to be in the La3+ valence state. Simultaneously, Fe atoms demonstrating oxidation states of Fe3+ can also be incorporated into the SrTiO3 network. The photocatalytic degradation of ciprofloxacin antibiotic revealed that the highest performance was approximately 75% within 9 h over the La0.01Sr0.99Fe0.01Ti0.99O3 sample prepared at 5 M of NaOH via the dynamic hydrothermal process. Meanwhile, this photocatalyst also displayed greater activity than the pristine SrTiO3, the single-doped samples (SrFe0.01Ti0.99O3 and La0.01Sr0.99TiO3), and the La0.01Sr0.99Fe0.01Ti0.99O3 sample prepared through a static hydrothermal technique under the same synthesis condition.


Assuntos
Luz , Óxidos , Hidróxido de Sódio , Catálise , Óxidos/química
4.
Chemosphere ; 292: 133516, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34990721

RESUMO

The thermochemical conversion of abundant renewable resources through pyrolytic catalysis cracking (PCC) is one of the most promising technologies for producing green biofuels. In this study, the pyrolysis of palm oil was investigated over a sustainable CaO-based catalyst derived from waste gypsum. PCC was conducted in a continuous packed-bed reactor under atmospheric pressure without purge gas. The effects of Mg doping and reaction temperature were also examined. A wet ball milling process was used to prepare the well-mixed catalysts and to subsequently form a heterojunction structure between the CaO and MgO particles. CaO was synthesized using the Ca(OH)2 derived from the reaction between gypsum and sodium hydroxide. The pyrolytic oil was separated from the crude oil to remove water and other impurities. The pyrolytic oil was then distilled following ASTM D86, and the three separated products were classified as bio-gasoline, bio-kerosene, and bio-diesel. The highest renewable light fuel volume (bio-gasoline and bio-kerosene) of about 75% (74 %wt.) was obtained at a reaction temperature of 525 °C with 10% MgCO3 content. The percent volume of light fuel increased with increasing reaction temperature. Renewable light fuel production over the Mg-doped CaO-based catalyst was related to both the Mg content and reaction temperature.


Assuntos
Magnésio , Pirólise , Biocombustíveis , Cálcio , Sulfato de Cálcio , Catálise , Temperatura Alta
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