title: Arsenic removal by modified activated carbons with iron hydro(oxide) nanoparticles.
abstract: Different activated carbons modified with iron hydro(oxide) nanoparticles were tested for their ability to adsorb arsenic from water. Adsorption isotherms were determined at As (V) concentrations < 1 ppm, with varying pH (6, 7, 8) and temperature (25 and 35 °C). Also, competition effect of anions on the As (V) adsorption capacity was evaluated using groundwater. The surface areas of the modified activated carbons ranged from 632 m(2) g(-1) to 1101 m(2) g(-1), and their maximum arsenic adsorption capacity varied from 370 μg g(-1) to 1250 μg g(-1). Temperature had no significant effect on arsenic adsorption; however, arsenic adsorption decreased 32% when the solution pH increased from 6 to 8. In addition, when groundwater was used in the experiments, the arsenic adsorption considerably decreased due to the presence of competing anions (mainly SO(4)(2-), Cl(-) and F(-)) for active sites. The data from kinetic studies fitted well to the pseudo-second-order model (r(2) = 0.98-0.99). The results indicated that sample CAZ-M had faster kinetics than the other two materials in the first 10 min. However, sample F400-M was only 5.5% slower than CAZ-M. The results of this study show that iron modified activated carbons are efficient adsorbents for arsenic at concentrations lower than 300 μg L(-1).
authors.affiliation: Division of Environmental Sciences, Instituto Potosino de Investigación Científica y Tecnológica, A.C. Camino a la Presa San José 2055, Col. Lomas 4ta. Sección, C.P. 78216 San Luis Potosí, S.L.P., Mexico.
authors.forename: Alma Veronica
authors.initials: AV
authors.lastname: Vitela-Rodriguez
authors.forename: Jose Rene
authors.initials: JR
authors.lastname: Rangel-Mendez
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000302:isolation & purification*; D002606:Charcoal / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D008956:Models, Chemical; D013696:Temperature; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D005290:Ferric Compounds; D014874:Water Pollutants, Chemical; D002606:Charcoal; C021024:ferric hydroxide; D001151:Arsenic