Role of Surface Oxygen-Containing Functional Groups in Liquid-Phase Adsorption of Nitrogen Compounds on Carbon-Based Adsorbents

Abstract

The carbon-based adsorbents are promising for adsorptive denitrogenation (ADN) of liquid hydrocarbon streams. The objective of the present study is to develop a fundamental understanding of the role of surface oxygen-containing functional groups on carbon-based adsorbents in adsorption of nitrogen compounds that are known to be present in liquid fuels. The adsorption properties of four representative activated carbons were evaluated in a batch adsorption system for removing quinoline and indole respectively from decane. The adsorption was found to obey the Langmuir adsorption isotherm. The adsorption isotherms were obtained and the adsorption parameters (the maximum capacity and adsorption constant) were estimated. The surface chemical properties of the adsorbents were characterized by temperature-programmed desorption (TPD) technique with a mass spectrometer to identify and quantify the type and concentration of the oxygen-containing functional groups on the basis of the CO 2 -and CO-evolution profiles. It was found that both the type and the concentration of surface oxygen-containing functional groups play an important role in determining the ADN performance. Higher concentration of the oxygen-containing functional groups on the adsorbents resulted in higher adsorption capacity for the nitrogen compounds. A fundamental insight was gained on the contributions of different oxygen functional groups by analyzing the changes in the monolayer maximum adsorption capacity q m and the adsorption constant K for nitrogen compounds on different carbon adsorbents. The acidic functional groups, such as carboxyl and carboxylic anhydride groups, appear to contribute more for adsorption of quinoline, whereas the basic oxygen-containing groups such as carbonyl and quinone groups may have more contribution to adsorption of indole.

A microbial fuel cell-coupled constructed wetland promotes degradation of azo dye decolorization products

“…This may because of the anode layer of this study was filled with GAC while the anode of the researches mentioned before were made of carbon paper, carbon fibre or carbon felt, and the anode chamber of these researches were filled with liquid. Studies have confirmed that the surface oxygen-containing groups of activated carbon can affect the catalytic performance and change the oxidation-reduction characteristic and promote the reduction reaction (Almarri et al, 2009). In this study, no 1, 4-Benzenediamine, N-methyl-or PPD were detected in the bottom layer despite there was DMPD existence.…”

Trace Analysis of Carbazole in Commercial Diesel by using Adsorption on Activated Biochar from Rice Husk Pyrolysis

“…Adsorptive denitrogenation and desulphurization is considered promising methodology when compared with the conventional hydrodenitrogenation and hydrodesulphurization process, because it can be run at ambient conditions without using hydrogen and catalysts [32]. The importance of denitrogenation process results from the fact that although nitrogen compounds are present at low concentrations, they play an important role in the quality of oil products.…”

“…In recent years, researchers have explored environmental friendly and low cost materials as precursors to prepare ACs that presented high apparent specific surface areas and good performance when tested as adsorbents for nitrogen compounds [32,38].Examples of these materials are biochars from the pyrolysis or combustion of biomasses. The possibility of producing carbon materials with high specific surface areas and micropore volume allied with a considerable surface reactivity make these materials adequate for a great number of applications.…”

Fluorescence of A100 MOF and Adsorption of Water, Indole, and Naphthalene on A100 by the Spectroscopic, Kinetic, and DFT Studies

“…3 Upon combustion of nitrogen-containing fuels, toxic nitrogen oxides are released that cause air pollution. The adsorption of aromatic N-heterocyclic compounds from liquid fuels was studied on zeolites, activated carbons, 4 and novel sorbents such as ionic liquids. 5 Metal−organic frameworks (MOFs) have a very high surface area and pore volume and are well suited for adsorption.…”