Carbons
Mostrando 13-24 de 358 artigos, teses e dissertações.
-
13. Surface modification of activated carbon by corona treatment
Surface modification may lead activated carbon (AC) to take on different properties. This study aimed to promote surface modification of activated carbons using corona treatment (electrical discharge). In this study, powdered commercial activated carbon was used. Activated carbons were subjected to corona treatment at different exposure times (2, 5, 8 and 10
An. Acad. Bras. Ciênc.. Publicado em: 21/03/2019
-
14. Grafting of Quinones on Carbons as Active Electrode Materials in Electrochemical Capacitors
The electrochemical performance of electrochemical capacitors can be improved with electroactive quinone molecules. Systems based on redox active electrolyte as well as physisorbed and chemically grafted molecules have been investigated. In all these cases, carbon materials were used as substrate and electrode material. This short review will mainly describe
J. Braz. Chem. Soc.. Publicado em: 2018-05
-
15. Competitive Adsorption of Dye Species onto Biomass Nanoporous Carbon in Single and Bicomponent Systems
ABSTRACT We first present a cost-effective approach to simultaneously dispose of rutaceae plant waste (the discarded peels of orange, finger citron, pomelo and lemon) to yield biomass nanoporous carbons (BNCs). The adsorption of orange II (OII) and acid chrome blue K (ACBK) from aqueous solutions in single and binary dye systems by four types of BNCs were st
Braz. J. Chem. Eng.. Publicado em: 2018-01
-
16. Synthesis and Impregnation of Copper Oxide Nanoparticles on Activated Carbon through Green Synthesis for Water Pollutant Removal
In this article was developed a green synthesis of CuO nanoparticles on vegetal activated carbon (VAC), using pomegranate leaf extract as reducing and stabilizing agent in the removal of multiple pollutants. The impregnated carbons with CuO nanoparticles were characterized morphologically and structurally. The SEM and XRD analysis, after carbons modification
Mat. Res.. Publicado em: 11/12/2017
-
17. Conformational Analysis, Experimental and GIAO-DFT 13C NMR Chemical Shift Calculation on 2’-Hydroxy-3,4,5-trimethoxy-chalcone
In this paper we investigated the ability of the GIAO-mPW1PW91/6-31G(d)//mPW1PW91/6-31G(d) level of theory to predict the 13C nuclear magnetic resonance (NMR) chemical shifts of the 2’-hydroxy-3,4,5-trimethoxy-chalcone molecule. Two different approaches were used. First: the absolute shieldings σ for all carbon atoms in each geometrically optimized confor
J. Braz. Chem. Soc.. Publicado em: 2017-11
-
18. Effect of Activated Carbons on the Dielectric and Microwave Properties of Natural Rubber Based Composites
The effect of six different types of activated carbons has been studied in view of their applicability as functional fillers upon the dielectric and microwave properties of natural rubber based composites. It is found that the textural characteristics of the studied active carbons exert influence both on the real part of dielectric permittivity and dielectri
Mat. Res.. Publicado em: 06/07/2017
-
19. Thermogravimetric and spectroscopic study (TG–DTA/FT–IR) of activated carbon from the renewable biomass source babassu
Activated carbons (ACs) with well–developed microstructure and high microporosity were obtained from biomass by potassium hydroxide activation. The preparation process consisted in producing carbon materials in the ratios of activating agent to raw material 70:30, 50:50, 30:70 and 25:75 (w/w) characterized by thermal analysis coupled to spectroscopy (TG–
Quím. Nova. Publicado em: 2017-04
-
20. A quantitative relationship between Tgs and chain segment structures of polystyrenes
Abstract The glass transition temperature (Tg) is a fundamental characteristic of an amorphous polymer. A quantitative structure-property relationship (QSPR) based on error back-propagation artificial neural network (ANN) was constructed to predict Tgs of 107 polystyrenes. Stepwise multiple linear regression (MLR) analysis was adopted to select an optimal su
Polímeros. Publicado em: 2017-03
-
21. APROVEITAMENTO DE RESÍDUO DE BIODIESEL PARA PREPARAÇÃO DE CARVÕES ÁCIDOS COM ELEVADA ATIVIDADE CATALÍTICA NA REAÇÃO DE ETERIFICAÇÃO DO GLICEROL
Environmentally friendly acid carbon (CG) catalysts, containing a high amount of sulfonated and oxygenated groups, were prepared from glycerin, a biodiesel waste. CGs were produced by glycerin carbonization in the presence of H2SO4 at 1:3 m:m ratio in a closed autoclave at 180ºC for different times: 0.25; 1; 3 and 6 hours (CG-0.25h; CG-1h; CG-3h and CG-6h,
Quím. Nova. Publicado em: 2015-05
-
22. Upgrade of Biofuels Obtained from Waste Fish Oil Pyrolysis by Reactive Distillation
Bio-oil is classified as second-generation biofuel and it is produced mainly through the pyrolysis of a waste lignocellulosic biomass base. The application of this product is still very limited, due to some of its chemical characteristics. This paper presents a proposal for the reduction of the acidity of bio-oil obtained from waste fish oil, previously prod
J. Braz. Chem. Soc.. Publicado em: 2015-02
-
23. Effect of the length of alkyl side chains in the electronic structure of conjugated polymers
Computational modeling studies of conjugated polymers have been shown to present many challenges. One such challenge is to find ways to reduce the computational cost for these studies without compromising the quality of the results. An approach longly used in the literature for this purpose is replacing long alkyl side chains (with six or more carbons) with
Mat. Res.. Publicado em: 05/08/2014
-
24. Metabolite profiling of Schizochytrium sp. by GC-MS, an oleaginous microbial source of biodiesel
The chemical screening carried out on Schizochytrium sp. biomass led the identification of 24 types of organic compounds belonging to n-alkanes, 1-alkenes, 1-alkanols, free fatty acids, methyl and ethyl esters of saturated and unsaturated fatty acids, saturated tri- and diglycerides, unsaturated monoglycerides, wax esters, sterols, triterpenes, and mono- and
Braz. J. Microbiol.. Publicado em: 2014-06