Determination of the Adsorption Isotherm of Vapor-Phase Mercury Chloride on Powdered Activated Carbon Using Thermogravimetric Analysis

Abstract

This study investigated the use of thermogravimetric analysis (TGA) to determine the adsorptive capacity and adsorption isotherm of vapor-phase mercury chloride on powdered activated carbon (PAC). The technique is commonly applied to remove mercury-containing air pollutants from gas streams emitted from municipal solid waste incinerators. An alternative form of powdered activated carbon derived from a pyrolyzed tire char was prepared for use herein. The capacity of waste tire-derived PAC to adsorb vapor-phase HgCl 2 was successfully measured using a self-designed TGA adsorption system. Experimental results showed that the maximum adsorptive capacities of HgCl 2 were 1.75, 0.688, and 0.230 mg of HgCl 2 per gram of powdered activated carbon derived from carbon black at 30, 70, and 150°C for 500 g/m 3 of HgCl 2 , respectively. Four adsorption isotherms obtained using the Langmuir, Freundlich, Redlich-Peterson, and BrunauerEmmett-Teller (BET) models were used to simulate the adsorption of HgCl 2 . The comparison of experimental data associated with the four adsorption isotherms indicated that BET fit the experimental results better than did the other isotherms at 30°C, whereas the Freundlich isotherm fit the experimental results better at 70 and 150°C. Furthermore, the calculations of the parameters associated with Langmuir and Freundlich isotherms revealed that the adsorption of HgCl 2 by PAC-derived carbon black favored adsorption at various HgCl 2 concentrations and temperatures.

Removal and recovery of gas-phase element mercury by metal oxide-loaded activated carbon

“…The lost weight fraction of spent AC-Mn between 700 K and 950 K reached 0.521 wt.% (5.21 mg g −1 HgO or 4.824 mg g −1 Hg) which was attributed to adsorbed HgO decomposition. Compared with MnO 2 /Al 2 O 3 's 2.2 mg g −1 (399 K) [18] and AC's 0.23 mg g −1 (423 K) [11], AC-Mn's capacity had been greatly improved even at higher adsorption temperature (523 K). AC-Co had higher capacity than AC-Mn due to its higher Hg 0 capture ability and longer breakthrough time.…”

“…Lin et al used TGA to determine the adsorptive capacity and adsorption isotherm of vapor-phase mercury chloride on powdered activated carbon [11,12]. In this study, we used TGA to analyze the adsorbed mercury species of spent sorbents.…”

“…Virgin activated carbon (AC) showed less Hg 0 capture ability, especially at high temperatures [11,12]. For this reason, chemically treated AC, such as sulfur (S), chlorine (Cl) and iodine (I) impregnated AC [13][14][15], were applied for the mercury emission control.…”

Competition among Mixed Adsorbates Affecting the Adsorption of Gaseous Methyl Ethyl Ketone by Hydrophobic Molecular Sieve

“…where a is mass of adsorbate required to saturate completely a unit mass of adsorbent; and b is the Langmuir adsorption constant (Reynolds and Richards, 1995;Lin et al, 2006). Values of a and b are constants to be determined by performing a series of isothermal continuous-flow column tests (Benefield, et al, 1982).…”

Kinetic Modeling on the Adsorption of Vapor-Phase Mercury Chloride on Activated Carbon by Thermogravimetric Analysis

“…The temperature of flue gas at which PAC is injected into the flue gas of MSW incinerators is 150°C, 19 and 30°C was used because it is close to room temperature. [15][16][17][18] A detailed description of the TGA furnace and reaction chamber has been previously reported in the literature. 16 …”