Adsorption of phenolic compounds by activated carbon—a critical review

A review on the preparation of the activated carbon from agricultural waste material is presented. The physical properties such as proximate and ultimate analysis of agricultural waste material were reviewed. The chemical compositions such as cellulose, hemicelluloses and lignin contents were also discussed. The effects of various parameters on the preparation such as carbonization and activation temperature, time, types of activating agents and impregnation ratio were reviewed. Various physical and chemical processes for the activation of the agricultural residues and their effects on the textural properties such as surface area and pore volume were discussed. The low cost, renewable and relatively less expensive of the agricultural waste were found to be efficiently being converted into wealth. The uses of activated carbon derived from agricultural residues in many fields were evidently proven in the review. The reaction kinetic modeling on the pyrolysis and activation of agricultural wastes were also reviewed.

Agricultural bio-waste materials as potential sustainable precursors used for activated carbon production: A review

Effects of activated carbon surface chemistry and pore structure on the adsorption of organic contaminants from aqueous solution

Non-thermal plasmas for non-catalytic and catalytic VOC abatement.

Abstract The objective of this research was to develop activated carbon selection criteria that assure the effective removal of trace organic contaminants from aqueous solution and to base the selection criteria on physical and chemical adsorbent characteristics. To systematically evaluate pore structure and surface chemistry effects, a matrix of activated carbon fibers (ACFs) with three activation levels and four surface chemistry levels was prepared and characterized. In addition, three granular activated carbons (GACs) were studied. Two common drinking water contaminants, relatively polar methyl tertiary-butyl ether (MTBE) and relatively nonpolar trichloroethene (TCE), served as adsorbate probes. TCE adsorbed primarily in micropores in the 7–10 A width range while MTBE adsorbed primarily in micropores in the 8–11 A width range. These results suggest that effective adsorbents should exhibit a large volume of micropores with widths that are about 1.3 to 1.8 times larger than the kinetic diameter of the target adsorbate. Hydrophobic adsorbents more effectively removed both TCE and MTBE from aqueous solution than hydrophilic adsorbents, a result that was explained by enhanced water adsorption on hydrophilic surfaces. To assure sufficient adsorbent hydrophobicity, the oxygen and nitrogen contents of an activated carbon should therefore sum to no more than about 2 to 3 mmol/g.

Effects of activated carbon surface chemistry and pore structure on the adsorption of trace organic contaminants from aqueous solution

Removal of VOCs from humidified gas streams using activated carbon cloth

This research examined the use of activated carbon cloths (ACC) to remove low concentrations of acetaldehyde, acetone, benzene, and methyl ethyl ketone from air. This work has applications in producing filtration systems for indoor air environments, industrial gas streams, and spray paint booths. Adsorption isotherms were measured for volatile organic compound adsorbate concentrations in the 10−1000 ppmv range and for water vapor from 0 to 95% relative humidity. The Dubinin−Radushkevich model was used to predict equilibrium adsorption capacities in the 100 ppbv to 10 000 ppmv concentration range. The adsorption of acetone−benzene mixtures on ACC was experimentally measured and then modeled using ideal adsorbed solution theory.

Gas Phase Adsorption of Volatile Organic Compounds and Water Vapor on Activated Carbon Cloth

The micropore surfaces of activated carbon cloths (ACCs) have been chemically modified by introducing controlled amounts of nitrogen, oxygen, or chlorine on the surface of the micropores. The treatments with ammonia, oxidative reagents, or chlorine produce surfaces that are basic, acidic, and polar, respectively. The modified ACCs were evaluated for removal of several different volatile organic compounds (VOCs) in the 10-1000 ppmv concentration range. VOCs examined included acetaldehyde, acetone, and benzene. Acetaldehyde adsorption capacity increased by 500% with oxidized ACC surfaces as compared to untreated ACC surfaces. Acetone adsorption was also enhanced by 350% on oxidized surfaces. The level of benzene uptake was high with most all of the treated surfaces. Thermal regeneration of the ACCs at 100 °C was sufficient to desorb each of the three VOCs without any decrease in the adsorption capacity of the treated ACCs.

Chemically treated activated carbon cloths for removal of volatile organic carbons from gas streams: evidence for enhanced physical adsorption.

High temperature hydrogen sulfide adsorption on activated carbon. I. Effects of gas composition and metal addition

Volatile organic compounds (VOCs) emitted to the atmosphere can cause adverse effects on human health and participate in photochemical smog formation reactions. Title III of the 1990 Clean Air Act Amendments (CAAA) requires that the U.S. Environmental Protection Agency (EPA) promulgate emission standards for 188 hazardous air pollutants (HAPs) associated with about 300 major source categories. Many industrial facilities throughout the U.S. will need pollution abatement systems for HAPs in order to be in compliance. Non-thermal plasma can be used to generate gas-phase free radicals (O( 1 D), O( 3 P), OH . ) at low temperature (293 K), which can then be used to destroy pollutants, such as benzene. The destruction of benzene was examined in planar dielectric barrier discharge plasma reactors as a function of applied voltage, benzene concentration, residence time and relative humidity. Near complete destruction of benzene (>99%) was achieved in both wet and dry gas streams.

Mark P. Cal

Papers

Removal of VOCs from humidified gas streams using activated carbon cloth

Gas Phase Adsorption of Volatile Organic Compounds and Water Vapor on Activated Carbon Cloth

Chemically treated activated carbon cloths for removal of volatile organic carbons from gas streams: evidence for enhanced physical adsorption.

High temperature hydrogen sulfide adsorption on activated carbon. I. Effects of gas composition and metal addition

Destruction of Benzene with Non-Thermal Plasma in Dielectric Barrier Discharge Reactors