ABSTRACT
Chemical upcycling of waste polyethylene terephthalate (PET) to value-added products can reduce the emission of CO2, microplastics and toxic chemicals. In this work, mesoporous H-type Zeolite Socony Mobil-5 (HZSM-5) supported Ru catalyst (Ru/m-HZSM-5) was synthesized and tested in the hydrogenation of PET degraded chemicals (bis(2-hydroxyethyl) terephthalate, dimethyl terephthalate, diethyl terephthalate, and terephthalic acid). Characterizations disclosed that Ru/m-HZSM-5 catalyst possesses mesopores (a dominant channel of 5.32 nm), enlarged specific surface area (404 m2·g-1), and Ru NPs dispersed highly (40.6 %) compared to that of Ru/HZSM-5. And also, it was found that Ru/m-HZSM-5 was capable for the hydrogenation of benzene rings in these PET degraded chemicals with large sizes (1.09-1.82 nm). In particular, the conversion of BHET and the selectivity of BHCD over Ru/m-HZSM-5 reached 95.5 % and 95.6 % at 120 °C within 2 h. And Ru/m-HZSM-5 could be recycled at least five times without obvious loss of activity and selectivity.
ABSTRACT
Catalytic wet air oxidation (CWAO) is a harmless, cheap and effective technology for the degradation of toxic containments directly to CO2 and H2O. In this work, highly dispersed Cu(II)/Cu(I)-N that embedded in the framework of g-C3N4 (Cux-g-C3N4) were synthesized in a facile thermal polymerization method and used in the CWAO of phenols, antibiotics and vitamins. Characterization results confirmed that g-C3N4 formed in the prepared catalyst and copper was chemically coordinated with N in g-C3N4, which inhibited the aggregation of copper. Meanwhile, Cu(II) or Cu(I) in the framework of g-C3N4 was more effective for the degradation of phenol than Cu(0) and CuO, and more than 23 toxic containments could be degraded under mild conditions. The prominent performance of Cu0.1-g-C3N4 for CWAO reaction was discussed on the base of these experiments and it was disclosed that in-situ formed H2O2 might be contributed to the highly activity.
Subject(s)
Hydrogen Peroxide , Phenol , Catalysis , Copper , Oxidation-ReductionABSTRACT
Oral administration of medicine faces physiological constraints imposed by the gastrointestinal tract (GIT) and simultaneously causes irritation to GI mucosa, which motivates us to pursue the innovation of a GI drug delivery system. Inspired by the mucosa-nutrient functions of Zinc element and smectite clay, a montmorillonite (MMT)-enveloped zeolitic imidazolate framework (M-ZIF-8) is developed in a successive one-pot fabrication of ZIF-8 encapsulated medicine, and followed MMT coating to yield a core-shell nanoplatform for GI drug delivery. ZIF-8 encapsulated medicines can maintain their intrinsic structure, and MMT layer potentiates mucous-adhesion and optimizes medicine release. Validated in gastritis and colitis models, M-ZIF-8 not only achieves efficient GI delivery of nonsteroidal anti-inflammatory drugs (NSAIDs) for inflammation inhibition, but also reduces the NSAIDs-induced GI irritation, promoting mucosal healing in GIT. Coupled with the facile construction and biocompatibility, M-ZIF-8 shows a significant advancement in GI drug delivery.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Bentonite/chemistry , Drug Delivery Systems , Gastrointestinal Agents/pharmacology , Gastrointestinal Tract/drug effects , Metal-Organic Frameworks/chemistry , Administration, Oral , Animals , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Colitis/chemically induced , Colitis/drug therapy , Colitis/metabolism , Dextran Sulfate , Gastrointestinal Agents/administration & dosage , Gastrointestinal Agents/chemistry , Gastrointestinal Tract/metabolism , Humans , Imidazoles/administration & dosage , Imidazoles/chemistry , Inflammation/chemically induced , Inflammation/drug therapy , Inflammation/metabolism , Male , Metal-Organic Frameworks/administration & dosage , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Molecular Structure , Particle Size , Surface Properties , Tumor Cells, Cultured , Zeolites/administration & dosage , Zeolites/chemistryABSTRACT
Decarboxylation of fatty acids over non-noble metal catalysts without added hydrogen was studied. Ni/C catalysts were prepared and exhibited excellent activity and maintenance for decarboxylation. Thereafter, the effects of nickel loading, catalyst loading, temperature, and carbon number on the decarboxylation of fatty acids were investigated. The results indicate that the products of cracking increased with high nickel loading or catalyst loading. Temperature significantly impacted the conversion of stearic acid but did not influence the selectivity. The fatty acids with large carbon numbers tend to be cracked in this reaction system. Stearic acid can be completely converted at 370 °C for 5 h, and the selectivity to heptadecane was around 80%.
ABSTRACT
A series of fatty acids in microalgae oil, such as stearic acid, palmitic acid, lauric acid, myristic acid, arachidic acid and behenic acid, were selected as the raw materials to produce aviation fuel via hydrothermal decarboxylation over a multi-wall carbon nanotube supported Pt catalyst (Pt/MWCNTs). It was found that Pt/MWCNTs catalysts exhibited higher activity for the hydrothermal decarboxylation of stearic acid with a 97% selectivity toward heptadecane compared to Pt/C and Ru/C under the same conditions. And Pt/MWCNTs is also capable for the decarboxylation of different fatty acids in microalgae oil. The reaction conditions, such as Pt/MWCNTs loading amount, reaction temperature and time were optimized. The activation energy of stearic acid decarboxylation over Pt/MWCNTs was calculated (114 kJ/mol).
Subject(s)
Biofuels , Biomass , Bioreactors , Fatty Acids/chemistry , Microalgae/metabolism , Aircraft , Alkanes/chemistry , Carbon/chemistry , Catalysis , Decarboxylation , Kinetics , Nanotubes, Carbon/chemistry , Stearic Acids/chemistry , Temperature , Time FactorsABSTRACT
Production of 1,2-propanediol (1,2-PDO) from glycerol hydrogenolysis was carried out in bio-ethanol solvent over small amount of Rh-promoted Cu/solid-base catalysts prepared via layered double hydroxide precursors. It was found that glycerol hydrogenolysis proceeded easily on Rh-Cu/solid-base catalysts than separated Rh and Cu/solid-base. The conversion of glycerol and selectivity to 1,2-PDO over Rh(0.02)Cu(0.4)/Mg(5.6)Al(1.98)O(8.57) reached 91.0% and 98.7%, respectively, at 2.0 MPa H(2), 180 °C. And this catalyst was stable in five consecutive hydrogenolysis tests in ethanol.
Subject(s)
Biofuels , Ethanol/chemistry , Glycerol/chemistry , Propylene Glycols/chemical synthesis , Propylene Glycols/isolation & purification , Solvents/chemistry , CatalysisABSTRACT
Hydrogenolysis of biodiesel derived glycerol to 1,2-propanediol (1,2-PDO) has attracted much attention in recent years. In this work, glycerol hydrogenolysis to 1,2-PDO was performed over CuO/MgO catalysts prepared by impregnation and coprecipitation at 180 degrees C and 3.0 MPa H(2). It was found that the Cu(15)/MgO catalyst prepared by coprecipitation had the best activity. The conversion of glycerol and the selectivity of 1,2-PDO over Cu(15)/MgO reached 72.0% and 97.6%, respectively. And the conversion of glycerol was further increased to 82.0% when small amount of NaOH was added in the reaction mixture. Those highly active catalysts were characterized by X-ray diffraction, transmission electron microscopy, N(2)-adsorption and temperature-programmed reduction with H(2). Characterization results revealed that the activity of the prepared catalysts depended strongly on the particle sizes of both Cu and MgO. Catalysts that have smaller sized Cu and MgO particles are more active for glycerol hydrogenolysis.