title: Enhancement of elemental mercury adsorption by silver supported material.
abstract: Mercury, generally found in natural gas, is extremely hazardous. Although average mercury levels are relatively low, they are further reduced to comply with future mercury regulations, which are stringent in order to avoid releasing to the environment. Herein, vapor mercury adsorption was therefore investigated using two kinds of supports, granular activated carbon (GAC) and titanium dioxide (TiO2). Both supports were impregnated by silver (5 and 15 wt.%), before testing against a commercial adsorbent (sulfur-impregnated activated carbon, SAC). The adsorption isotherm, kinetics, and its thermodynamics of mercury adsorption were reported. The results revealed that Langmuir isotherm provided a better fit to the experimental data. Pseudo second-order was applicable to describe adsorption kinetics. The higher uniform Ag dispersion was a key factor for the higher mercury uptake. TiO2 supported silver adsorbent showed higher mercury adsorption than the commercial one by approximately 2 times. Chemisorption of mercury onto silver active sites was confirmed by an amalgam formation found in the spent adsorbents.
authors.affiliation: Department of Chemical Engineering, Thammasat University, Pathumthani 12120, Thailand.
authors.forename: Rattabal
authors.initials: R
authors.lastname: Khunphonoi
authors.affiliation: Environmental Research Institute, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand.
authors.forename: Pummarin
authors.initials: P
authors.lastname: Khamdahsag
authors.affiliation: Division of Environmental Technology, School of Energy, Environment and Materials, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand.
authors.forename: Siriluk
authors.initials: S
authors.lastname: Chiarakorn
authors.affiliation: Department of Chemical Engineering, Thammasat University, Pathumthani 12120, Thailand. Electronic address: gnurak@engr.tu.ac.th.
authors.forename: Nurak
authors.initials: N
authors.lastname: Grisdanurak
authors.affiliation: Division of Environmental Technology, School of Energy, Environment and Materials, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand.
authors.forename: Adjana
authors.initials: A
authors.lastname: Paerungruang
authors.affiliation: Petroleum Authority of Thailand (PTT) Research and Technology Institute, Wong-Noi, Ayutthaya 13170, Thailand.
authors.forename: Somrudee
authors.initials: S
authors.lastname: Predapitakkun
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D008628:Mercury / Q000302:isolation & purification*; D008855:Microscopy, Electron, Scanning; D059206:Natural Gas / Q000032:analysis*; D012834:Silver / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics; D014025:Titanium / Q000737:chemistry*; D014835:Volatilization; D014961:X-Ray Diffraction
chemical_list: D059206:Natural Gas; C009495:titanium dioxide; D002606:Charcoal; D012834:Silver; D014025:Titanium; D008628:Mercury
keywords: Adsorption; Amalgam; Mercury; Natural gas; Silver