Investigation of low-temperature regeneration of activated carbon

Abstract

Granular activated carbon loaded with aniIine, o-nitroaniline or o-nitrophenol, regenerated at relatively low temperature (450 ~ in No atmosphere), shows losses of cyclic adsorption performances (about 5 % per cycle) comparable to those occurring with standard thermal regeneration (950 ~ in controlled atmosphere). Adsorbate buildups and related surface modifications have been determined.Alternative regeneration techniques (i.e. chemical, biological, etc.) or substantial economic improvements of standard thermal regeneration are required to expand the application of active carbon (AC) in the field of pollution control. With this aim, promising implications have been associated to massive adsorbate release at relatively low temperatures (400-500~ as already evidenced in previous articles of this series [1][2][3]. In the present paper the cyclic performances of AC loaded with aniline (A), o-nitroaniline (ONA) or o-nitrophenol (ONF), thermally regenerated up to 450 ~ in Nz atmosphere, are presented. ExperimentalThe progressive decay of the adsorption capacity of AC thermally regenerated to about 450 ~ was followed by alternately submitting it to several adsorptionthermodesorption steps. About 100 mg of 16-25 (US) mesh dry AC (Filtrasorb 400 from Calgon Corp., Pittsburg, Pa.) was equilibrated with 100 ml of aqueous solution containing 300 ppm of aniline (A) or o-nitroaniline (ONA) or o-nitrophenol (ONF). The adsorbed amount was determined spectrophotometrically by analysis of the aqueous phase. After vacuum filtration, the samples were submitted to thermal analysis up to 450 ~ in a dynamic N~ atmosphere, using a model TA 1 Thermoanalyzer from Mettler AG, Ziirich, Switzerland, with a heating rate of 6~ A new adsorption cycle was then started and the decrease of adsorption capacity of each sample progressively recorded. In order to follow surface and porosity modifications through the cycles, 6 AC samples, equilibrated with each solute and routinely submitted to heating-readsorption treatment, were discharged after the 1st, 2nd, 4th, 5th, 8th and 10th cycle, respectively, *

Thermal analysis of activated carbon obtained from residue after supercritical extraction of hops

“…The waste of this type after specific thermochemical treatment can be a cheap precursor material for carbon absorbents to be applied for removal of pollutants. Obtaining of activated carbons of specific physicochemical properties needs the application of specific parameters of thermal treatment [32][33][34]. A method very useful for optimisation of activated carbons production and establishing thermal stability of the activation products is the thermogravimetric analysis [35,36].…”

Thermogravimetric and spectroscopic study (TG–DTA/FT–IR) of activated carbon from the renewable biomass source Babassu

“…[1][2][3][4][5][6] Such adsorbents may be derived from various sources like minerals and lignocellulosic material, even though the AC production from minerals presents some important disadvantages like high cost, low yields in carbonization and high ash content. [7][8][9][10] Alternatively, lignocellulosic materials from agro--industrial and agricultural wastes such as peels, seeds or bagasse offer great potential to be used as raw carbon precursors due to their high carbon content and already proven high adsorption capacity.…”

Studies of adsorption equilibria and kinetics of o-, m-, p-nitro- and chlorophenols on microporous carbons from aqueous solutions

“…11,12,13 and 14,curves b,c,d). At first up to 100°C we can observe on DTG and DTA curves the process of water removing (Amicarelli et al 1980). In the temperature Fig.…”