scholarly journals Direct catalytic effect of nitrogen functional groups exposed on graphenic materials when acting cooperatively with Ru nanoparticles

RSC Advances ◽  
2017 ◽  
Vol 7 (70) ◽  
pp. 44568-44577 ◽  
Author(s):  
Carolina Ramirez-Barria ◽  
Cristina López-Olmos ◽  
Antonio Guerrero-Ruiz ◽  
Inmaculada Rodríguez-Ramos
Keyword(s):  
Functional Groups ◽  
Aqueous Phase ◽  
Catalytic Effect ◽  
Carbon Materials ◽  
Ru Nanoparticles ◽  
Phase Oxidation ◽  
Furandicarboxylic Acid ◽  
Catalytic Effects

Various carbon materials (including doped graphenic materials) have been used as supports of Ru nanoparticles to determine their catalytic effects in the base-free aqueous-phase oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid.

Aqueous-phase oxidation of 5-hydroxymethylfurfural over Pt/ZrO2 catalysts: exploiting the alkalinity of the reaction medium and catalyst basicity

2016 ◽  
Vol 5 (4) ◽  
Author(s):  
Erica Daniele da Silva ◽  
Wilma A. Gonzalez ◽  
Marco A. Fraga
Keyword(s):  
Selective Oxidation ◽  
Aqueous Phase ◽  
Reaction Medium ◽  
Phase Oxidation ◽  
Furandicarboxylic Acid

AbstractThe basicity required for the aqueous-phase selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid (FDCA) is explored through different approaches. Homogeneous hydroxides were tested along with a Pt/ZrO

scholarly journals Effect of Air Oxidation on Texture, Surface Properties and Dye Adsorption of Wood-Derived Porous Carbon Materials

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1675 ◽  
Author(s):  
Suhong Ren ◽  
Liping Deng ◽  
Bo Zhang ◽  
Yafang Lei ◽  
Haiqing Ren ◽  
...  
Keyword(s):  
Surface Area ◽  
Functional Groups ◽  
Porous Carbon ◽  
Carbon Materials ◽  
Dye Adsorption ◽  
Carbon Surface ◽  
Air Oxidation ◽  
Activation Temperature ◽  
Porous Carbon Materials ◽  
Hierarchical Porous

Hierarchical porous carbon materials made from cork were fabricated using a facile and green method combined with air activation, without any templates and chemical agents. The influence of air activation on the texture and other surface characteristics of the carbon materials were evaluated by various characterization techniques. Results indicate that air oxidation can effectively improve the surface area and the hierarchical porous structure of carbon materials, as well as increase the number of oxygen-containing functional groups on the carbon surface. The specific surface area and the pore volume of the carbon material activated by air at 450 °C (C800-M450) can reach 580 m2/g and 0.379 cm3/g, respectively. These values are considerably higher than those for the non-activated material (C800, 376 m2/g, 0.201 cm3/g). The contents of the functional groups (C–O, C=O and O–H) increased with rising activation temperature. After air activation, the adsorption capacity of the carbon materials for methylene blue (MB) and methyl orange (MO) was increased from 7.7 and 6.4 mg/g for C800 to 312.5 and 97.1 mg/g for C800-M450, respectively. The excellent dye removal of the materials suggests that the porous carbon obtained from biomass can be potentially used for wastewater treatment.

Effect of the ionizing radiation on the catalytic activity of the BASF K-3-10 catalyst in the low-temperature conversion of carbon monoxide by water vapour. Stability of the radiation catalytic effects

1986 ◽  
Vol 51 (8) ◽  
pp. 1571-1578 ◽  
Author(s):  
Alois Motl
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Low Temperature ◽  
Catalytic Effect ◽  
Catalytic Properties ◽  
Beta Radiation ◽  
Fast Neutrons ◽  
Time Interval ◽  
The Stability ◽  
Catalytic Effects

The radiation catalytic properties of the BASF K-3-10 catalyst were studied, namely the dependence of these effects on the time interval between the catalyst irradiation and the reaction itself and also on the length of the catalyst use. The catalytic effects decrease exponentially with the interval between the irradiation and the reaction if the catalyst is kept in the presence of air. The stability of effects induced by various types of radiations increases in the sequence beta radiation - gamma radiation - fast neutrons. The radiation catalytic effect stability in the reaction increases in the same sequence.

scholarly journals Hydrophilic modification of polypropylene membranes and films by catalytic ozonation

2021 ◽  
Author(s):  
Hong Bin Gu
Keyword(s):  
Contact Angle ◽  
Functional Groups ◽  
Aqueous Phase ◽  
Gaseous Phase ◽  
Graft Polymerization ◽  
Copper Catalyst ◽  
Catalytic Ozonation ◽  
Sem Images ◽  
Hydrophilic Modification ◽  
Gaseous Media

Commercial polypropylene microfiltration membranes (PPMM) and biaxial oriented polypropylene (BOPP) films were ozonated in aqueous and gaseous media, respectively, followed by graft polymerization of acryl amide (AAm), hydroxyethyl methacrylate (HEMA), and polyethylene glycol (PEG) to improve their surface hydrophilicity. The efficiency of ozonation conducted in the gaseous and aqueous phases was compared, the gaseous phase ozonation was found slightly more effective in generating peroxide groups, while the aqueous phase ozonation was found more effective in grafting polymerization. Scavengers were added to the aqueous phase ozonation, results indicated that both the radical groups and the molecule ozone contributed to the peroxide generation. The free radical groups contributed maximum 25% and 32% for ozonation of PPMM and BOPP, respectively, and the molecule ozone contributed the percentage remaining. Results also showed that the concentration of peroxides generated on the surfaces of PPMM or BOPP increased with the applied ozone dose and ozonation time in both phases. Copper sulfate hydrate (CuSO4·5H2O) and ferric chloride hydrate (FeCl3·6H2O) were added in the aqueous phase ozonation as homogenous catalysts, results showed that the peroxide generation rate of PPMM and BOPP was improved comparing to that of ozonation without catalyst. The peroxide generation of PPMM showed 17% increase by adding copper catalyst, and 16% increase in peroxide generation was observed in ferric catalyzed ozonation of BOPP. The mechanism of the aqueous phase ozonation was investigated, along with that of catalytic ozonation. An enhanced radical process was found for catalytic ozonation in this study. The hydrophilicity of PPMM and BOPP was improved by graft polymerization of AAm, HEMA and PEG initiated by the peroxides. The aqueous phase ozonation was found more effective in grafting. A washing test was conducted using distilled water blending with 10% isopropyl alcohol. When the ozonated membranes and films were washed and compared to the non-washed ones, it was found that the gaseous phase ozonated PPMM or BOPP lost more peroxides than their aqueous phase counterpart after washing. The washing tests showed that the aqueous phase ozonation could induce a better graft polymerization, because part of the tested peroxides from the gaseous ozonation was washed away in the cleaning and grafting process. The improved hydrophilicity of PPMM was indicated by the contact angle reduction from 129° to 91° for AAm grafting; from 126° to 74° for HEMA grafting; and from 126° to 88° for PEG grafting; Fourier Transform Infrared (FTIR) measurements showed additional peaks of functional groups, such as amine (N-H) and amide (–N-C=O) functional groups from the grafted AAm (CH2=CH-CO-NH2); and the Scanning Electron Microscope (SEM) images confirmed amorphicity changes of the graft polymerization. X-ray Diffraction (XRD) diffractogram revealed the crystallinity changes of ozonated and grafted PPMM. Bovine serum albumin (BSA) was used to test the filtration performance of virgin and grafted membranes, the filtration tests demonstrated the improvement in anti-fouling effect of the modified PPMM; and the SEM images of the fouled and washed membranes revealed the pore blockage and recovering on the surface. The hydrophilicity of the grafted BOPP was also improved, indicated by the contact angle reduction of AAm grafted film from 80° to 56°. The FTIR showed additional peaks of N-H and –N-C=O functional groups of grafted AAm. SEM images indicated amorphicity changes of the graft polymerization. The film modified by the aqueous phase ozonation showed its advantages of better graft polymerization, hydrophilicity, and protein adsorption. The results of this study positively impacted the industrial using of PPMM to elongate its duration time of filtration, and improved the applications of BOPP in biomedical areas

scholarly journals 5-Hydroxymethylfurfural Oxidation Over Platinum Supported on Açaí Seed Coal for Synthesis of 2,5-Furandicarboxylic Acid

2021 ◽  
Vol 12 (5) ◽  
pp. 6632-6650
Keyword(s):  
Functional Groups ◽  
Renewable Resources ◽  
Activated Carbons ◽  
High Dispersion ◽  
Pt Catalysts ◽  
N2 Adsorption ◽  
Anchoring Effect ◽  
Furandicarboxylic Acid ◽  
Oxygenated Functional Groups ◽  
Petrochemical Industries

2,5-furandicarboxylic acid (FDCA) is produced from the selective oxidation of 5-hydroxymethylfurfural (HMF) and is an important platform molecule applied in the pharmaceutical and petrochemical industries. Activated carbons produced from renewable resources are useful materials due to their physicochemical properties, defined mainly by the oxygenated functional groups on their surface. This work studies the oxidation of HMF to FDCA over Pt catalysts supported on açaí coal. The catalysts were characterized by N2 adsorption, XPS, ToF-SIMS, FTIR, XRD, Raman, TEM, SEM, TPR-H2, and TGA/DTA. The conversion of HMF to FDCA in an alkaline medium occurred via hydroxymethyl-2-furancarboxylic acid (HMFCA), which was oxidized to 5-formylfurancarboxylic acid (FFCA) and FDCA. The catalytic tests showed a high conversion of HMF with a 93.6% yield of FDCA. The excellent results were attributed to the high dispersion of Pt on the support and the presence of oxygenated functional groups on the coal surface. The functional groups increased the interaction between Pt-HMF and Pt-furan intermediates and favored a higher dispersion of platinum (53.3%) due to an anchoring effect.

scholarly journals The impact of functional groups of the surface of carbon materials on the efficiency of purification of extraction phosphoric acid from fluorine compounds

2019 ◽  
Vol 2 ◽  
pp. 11-18
Author(s):  
Smirnov N.N. ◽  
Konoval A.V. ◽  
Smirnova D.N. ◽  
Kochetkov S.P.
Keyword(s):  
Phosphoric Acid ◽  
Functional Groups ◽  
Carbon Materials ◽  
Raw Materials ◽  
Carbon Adsorbents ◽  
Joint Stock Company ◽  
Stock Company ◽  
Fluorine Compounds ◽  
The Impact ◽  
Extraction Phosphoric Acid

The environmental problems of the production of extraction phosphoric acid and the effect of fluorine on the human body are discussed in the article. The creation of the industry of phosphoric fertilizers on the basis of processing of fluorine-containing phosphate raw materials and fluorine-containing compounds, the development of their application require the study of environmental consequences arising from this, because fluorine is characterized by high mobility in the biological cycle of metabolism. For the purification of phosphoric acid from fluorine was used carbon adsorbents such as active charcoal brand BAU, natural graphite deposits Kyshtymsky, P514 soot, charcoal. Experiments on the purification was carried out on non-evaporated half-hydrated extraction phosphoric acid which was produced by joint stock company «Apatit» in Cherepovets city in Russia. The following analyses were carried out: IR-Fourier spectrometry, research of acid–base properties of carbon materials by potentiometric titration, potentiometric method of fluorine determination in extraction phosphoric acid. It is mentioned that the carbon black P514 is the most efficient adsorbent for purification of extraction phosphoric acid. The total number of functional groups on its surface is 0.62 mmol/g, the degree of purification from fluorine compounds is 94.8%.

scholarly journals The formation of nitro-aromatic compounds under high NO<sub><i>x</i></sub> and anthropogenic VOC conditions in urban Beijing, China

2019 ◽  
Vol 19 (11) ◽  
pp. 7649-7665 ◽  
Author(s):  
Yujue Wang ◽  
Min Hu ◽  
Yuchen Wang ◽  
Jing Zheng ◽  
Dongjie Shang ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Aromatic Compounds ◽  
Total Concentration ◽  
Fine Particulate Matter ◽  
Oxidation Products ◽  
Urban Atmosphere ◽  
Formation Pathway ◽  
Relative Contribution ◽  
Phase Oxidation ◽  
Nitro Aromatic

Abstract. Nitro-aromatic compounds (NACs), as important contributors to the light absorption by brown carbon, have been widely observed in various ambient atmospheres; however, their formation in the urban atmosphere was little studied. In this work, we report an intensive field study of NACs in summer 2016 at an urban Beijing site, characterized by both high-NOx and anthropogenic VOC dominated conditions. We investigated the factors that influence NAC formation (e.g., NO2, VOC precursors, RH and photolysis) through quantification of eight NACs, along with major components in fine particulate matter, selected volatile organic compounds, and gases. The average total concentration of the quantified NACs was 6.63 ng m−3, higher than those reported in other summertime studies (0.14–6.44 ng m−3). 4-Nitrophenol (4NP, 32.4 %) and 4-nitrocatechol (4NC, 28.5 %) were the top two most abundant NACs, followed by methyl-nitrocatechol (MNC), methyl-nitrophenol (MNP), and dimethyl-nitrophenol (DMNP). The oxidation of toluene and benzene in the presence of NOx was found to be a more dominant source of NACs than primary biomass burning emissions. The NO2 concentration level was found to be an important factor influencing the secondary formation of NACs. A transition from low- to high-NOx regimes coincided with a shift from organic- to inorganic-dominated oxidation products. The transition thresholds were NO2 ∼ 20 ppb for daytime and NO2∼25 ppb for nighttime conditions. Under low-NOx conditions, NACs increased with NO2, while the NO3- concentrations and (NO3-)/NACs ratios were lower, implying organic-dominated products. Under high-NOx conditions, NAC concentrations did not further increase with NO2, while the NO3- concentrations and (NO3-)/NACs ratios showed increasing trends, signaling a shift from organic- to inorganic-dominated products. Nighttime enhancements were observed for 3M4NC and 4M5NC, while daytime enhancements were noted for 4NP, 2M4NP, and DMNP, indicating different formation pathways for these two groups of NACs. Our analysis suggested that the aqueous-phase oxidation was likely the major formation pathway of 4M5NC and 3M5NC, while photo-oxidation of toluene and benzene in the presence of NO2 could be more important for the formation of nitrophenol and its derivatives. Using the (3M4NC+4M5NC) ∕ 4NP ratios as an indicator of the relative contribution of aqueous-phase and gas-phase oxidation pathways to NAC formation, we observed that the relative contribution of aqueous-phase pathways increased at elevated ambient RH and remained constant at RH > 30 %. We also found that the concentrations of VOC precursors (e.g., toluene and benzene) and aerosol surface area acted as important factors in promoting NAC formation, and photolysis as an important loss pathway for nitrophenols.

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